REESE LIBRARY L-TUJV UNIVERSITY OF CALIFORNIA., i , i go ^Accession No. 853/-^v" , Class No. HYDRAULIC POWER ENGINEERING OF THK UNIVERSITY ^ NIAGARA FALLS. [ Frontispiece. HYDRAULIC POWER ENGINEERING A PRACTICAL MANUAL ON THE CONCENTRATION AND TRANSMISSION OF POWER BY HYDRAULIC MACHINERY G. CROYDON MARKS \ ASSOCIATE MEMBER OF THE INSTITUTION OF CIVIL ENGINEERS MEMHER OF THE INSTITUTION OF MECHANICAL ENGINEERS FELLOW OF THE CHARTERED INSTITUTE OF PATENT AGENTS TOlitb over "Cwo *un5vc6 Illustrations LONDON CROSBY LOCKWOOD AND SON 7 STATIONERS' HALL COURT, LUDGATE HILL 1900 Printed at THE DARIEN PRESS, Edinburgh. PREFACE. THIS work may be regarded as a successor to a smaller volume by the same Author on " HYDRAULIC MACHINERY," published in 1891, which he prepared with a view to the assistance of engineering students and others who might be practically interested in the subject. In the present volume an attempt is made to give an outline discussion and description of the main points and principles requiring attention by engineers having the responsibility of designing or constructing works and appliances for the utilisation of water for the transmission of power. It would be impossible in any single volume to deal adequately or comprehensively with the many problems arising in the different sections into which the very large subject of Hydraulics and Hydraulic Engineering naturally divides itself. The Author, therefore, has contented himself with giving examples which have special reference to the particular sections in which they occur ; and in addition, he has en- deavoured to lead up to the general subject by a brief examination of the principles underlying the whole study. The development of hydraulic power machinery has been somewhat of a modern movement, but the examples which are to be found in the following pages 85372 VI PREFACE. will possibly lead the engineer and designer to go still further in the realisation of the most convenient form of power transmission available for industrial under- takings and commercial manufactures. In practice it is constantly found that new problems are raised, and new forms of machinery required for their satisfactory solution. The Author wishes to acknowledge here the ser- vices which have been rendered him by Mr E. B. Fenby and Mr A. Suggate, members of his staff, in the preparation of the examples and drawings given in the volume, and in compiling many of the tables now published here for the first time. Free use (it should also be mentioned) has been made of informa- tion published in the " Proceedings of the Institution of Civil Engineers," the permission of the Council of that Institution having been kindly given for that purpose ; and additional information has been obtained from descriptions of works appearing in the Engineer and Engineering, and in CassieSs Magazine. Many of the illustrations have been specially prepared from information kindly placed at the service of the Author by the several engineering firms referred to in the work. The Author would refer students who may seek fuller information on the question of Hydraulic Motors and Turbines to Mr Bodmcr's treatise upon that subject. 1 8 SOUTHAMPTON BUILDINGS, LONDON, W.C. January 1900. : f UNIVERSITY ^A.V CONTENTS PART L HYDRAULICS. CHAPTER I. I'AGE PRINCIPLES OF HYDRAULICS 3 CHAPTER II. THE OBSERVED FLOW OF WATER 21 PART If. PRELIMINARY. CHAPTER III. HYDRAULIC PRESSURES 35 CHAPTER IV. MATERIAL 44 CHAPTER V. TEST LOAD - - - 51 viii CONTENTS. PART II L JOINTS. CHAPTER VI. PAGE PACKINGS FOR SLIDING SURFACES - - 67 CHAPTER VII. PIPE JOINTS - 86 PART IV. VALVES. CHAPTER VIII. CONTROLLING VALVES - in PART V. LIFTING MACHINERY. CHAPTER IX. PLATFORM LIFTS - 131 CHAPTER X. WORKSHOP AND FOUNDRY CRANES - 176 CHAPTER XI WAREHOUSE AND DOCK CRANES 190 CHAPTER XII. HYDRAULIC ACCUMULATORS 197 CONTENTS. IX PART VI. HYDRAULIC PRESSES. CHAPTER XIII. I'AGE PRESSES FOR BALING AND OTHER PURPOSES - - 211 CHAPTER XIV. SHEET METAL WORKING AND FORGING MACHINERY 229 CHAPTER XV. HYDRAULIC RIVETERS - 239 PART VIL- PUMPS. CHAPTER XVI. HAND AND POWER PUMPS - 247 CHAPTER XVII. STEAM PUMPS 254 PART VIII. HYDRAULIC MOTORS. CHAPTER XVIII. TURBINES 263 CHAPTER XIX. IMPULSE TURBINES - - 271 CONTENTS. CHAPTER XX. PAGE REACTION TURBINES 280 CHAPTER XXI. DESIGN OF TURBINES IN DETAIL - 299 CHAPTER XXII. WATER WHEELS - 315 CHAPTER XXIII. HYDRAULIC ENGINES 319 CHAPTER XXIV. RECENT ACHIEVEMENTS 338 APPENDIX. TABLE SHOWING PRESSURE OF WATER IN LBS. PER SQUARE INCH FOR EVERY FOOT IN HEIGHT TO 2JO FEET 355 ACTION OF PUMPS : TABLE OF DIAMETERS, AREAS, AND DISPLACEMENTS IN IMPERIAL GALLONS PER FOOT OF TRAVEL - - - 356 INDEX - - 357 LIST OF TABLES. PAGE I. STRESSES IN HYDRAULIC MACHINERY FOR LOADS APPLIED IN ONE DIRECTION ONLY - 54 II. THICKNESS IN INCHES OF CAST-IRON CYLINDERS FOR TEST PRESSURES OF LBS. AND TONS PER SQUARE INCH - 58 III. THICKNESS OF STEEL CYLINDERS (UNHAM- MERED CASTINGS) FOR TEST PRESSURES OF TONS PER SQUARE INCH 59 IV. COEFFICIENTS OF RAM EFFICIENCIES FOR HEMP OR LEATHER PACKING 85 V. MAXIMUM LOADING FOR WROUGHT-IRON BOLTS 89 VI. DIMENSIONS OF CIRCULAR FLANGES OF CAST- IRON PIPES WITH TONGUED AND GROOVED JOINTS 96 VII. BREAKING WEIGHT OF STEEL WIRE ROPES - 165 VIII. COEFFICIENTS OF EFFICIENCY OF STEEL WIRE ROPE AND SHORT LINK CHAIN - - 169 xii LIST OF TABLES. PAGE IX. COEFFICIENTS OF EFFICIENCY OF PULLEY WHEELS TURNING ON PINS - - - - 170 X. PRESSES FOR BALING : PRESSURE IN TONS PER SQUARE FOOT OF FLATTEN TO BALE MATE- RIAL TO GIVEN WEIGHTS 212 XL SIZES OF WROUGHT-IRON BARS FOR PRESSES 220 XII. PRESSURE OF WATER IN LBS. PER SQUARE INCH FOR i TO 270 FEET IN HEIGHT - 355 XIII. ACTION OF PUMPS: DIAMETERS, AREAS, AND DISPLACEMENTS IN IMPERIAL GALLONS PER FOOT OF TRAVEL ------ 356 LIST OF ILLUSTRATIONS. FIG. PAGE Niagara Falls Frontispiece i, 2. Diagrams illustrating Equal Pressure on Surfaces - 9, 10 3. Diagram illustrating Principle of Archimedes 11 4. Hydraulic Ram 17 5-9. Appliances and Arrangements for Observing Flow of Water - 21-28 10. Diagram illustrating Flow of Water in Bends 30 11-13. Hydraulic Cylinders - - 41,42 14. Diagram illustrating Extension of Metal - 48 15. Cylinder in cross-section, showing Thickness of Walls - 55 16-24. Construction and Casting of Cylinders 60-63 25-28. Leather Packing for Plungers 67 29-33. Leather Cup Packings 68-70 34, 35. Leather Hat Packings 74 36-46. Leather U Packings - 75-79 47. Pipe Flange - 87 48, 49. Pipe Joints 91, 93 50-59. Do. 98-103 60-64. Pipe Swivelling Joints 104-107 65,66. Stop Valve - - - - 112,114 XIV LIST OF ILLUSTRATIONS. FIG. 67-69. Shock Valve - 70, 72. Slide Valve 71. Piston Valve - 73. Armstrong Valve 74. Spindle Valve 75, 76. Balanced Valve 77. Multiple Ram Lift 78, 79. Meacock's Valve 80-82. Ram Platform Lift 83. Intensifier 84, 85. Ellington's Lift 86. Multiple Chain Lift 87, 88. Suspended Passenger Lift 89. Safety Gear - 90. Otis Safety Gear 91, 92. Rope and Chain Wheels 93. Chain Pulleys 94, 95. Hydraulic Jack 96. Wall Crane - 97, 98. Foundry Crane 99. Travelling Lifting Ram 100. Shop Crane - 101. Direct Puller - 102. Duckham's Weigher 103. Multiple Jigger 104. Warehouse Crane 105. Travelling Wharf Crane 106. Dock Crane - 107-111. Accumulator - 112. Diagram illustrating Baling Pressure 113. Hydraulic Press 114. Bars of Hydraulic Press 1 1 5. Head of do. 1 1 6- 1 1 8. Baling Press 119. Punching Bear 115, 116 117, 121 118 122 123 124 124 126 134-137 148 152 156 158 161 163 1 66 171 177, 178 181 182, 184 185 1 86 187 1 88 191 192 194 195 199-206 214 218 219 221 224-227 230 LIST OF ILLUSTRATIONS. XV FlG. PAGE 120,121. Forging Press 231,233 122. Cylinders and Ram (in section) of Tweddell Punch 234 123,124. Plate Shears - 235,236 125. Plate Bender 237 126. Tube Drawing Bench 238 127. Wheel Press - 238 128-131. Riveters . 240-243 132-135. Hand Pressure Pump 247-250 136. Belt-driven Pumps 251 137, 138. Plunger Plump 252, 253 139-141. Worthington Pumps - 254-256 142. Fly- Wheel Pressure Pump 256 143. Vertical Cylinder Pump 257 144. Fly-Wheel Pump (Berry) 258 145. Diagram Illustrating Velocity of Turbine 264 146, 147. Girard Turbine 266 148. Pelton Wheel 267 149. Axial-flow Turbine 268 150. Thrust Bearing 269 151-156. Diagrams illustrating Impulse Turbines 272-278 157-164. Do. do. Reaction Turbines - 282-294 165-171. Regulations for Turbines 301-307 172. Overshot Water Wheel 316 173. Breast Water Wheel - 317 174. Undershot Water Wheel 318 175-179. Diagrams illustrating Action of Hydraulic Motors - - 322, 326 180-182. Brotherhood Engine 327, 328 183, 184. Armstrong Engine - 329, 330 185, 1 86. Armstrong Capstan - 331, 332 187. Valve of Early Armstrong Engine - 333 188, 189. Rigg Engine 334, 33^ 190. Hydraulic Dock at San Francisco - foc&tg$$& 191-193. Machinery of Tower Bridge on the Thames 340, 342 xvi LIST OF ILLUSTRATIONS. FlG. I'AGE 194. View of the Tower Bridge over the Thames facing 342 195. Water Balance Cliff Railway, in section - 344 196. Rail-gripping Brake for Cliff Railway 345 197. View of Cliff Railway at Lynton - facing $$6 198, 199. Glasgow Harbour Tunnel Lifts - 348, 350 200. 4,ooo-Ton Hydraulic Forging Press (Cammell's Works, Sheffield) - facing 352 201. Bird's-eye View of Hydraulic Power Instal- lation at Niagara Falls - facing 354 PART I. -HYDRAULICS. HYDRAULIC POWER ENGINEERING. CHAPTER I. PRINCIPLES OF HYDRAULICS. General Properties of Water There are certain properties of water which render it particularly suitable to the requirements of the hydraulic power engineer. There are three distinct methods of using water for transmitting power. By the first method the water is placed at some height above a given datum level, and by its descent is caused to turn a water-wheel. In this case the water acts by its large weight and high viscosity; and if either of these two properties were wanting, the water would be of small use for this method. By the second method the water is subjected to great pressure, and is applied to a piston moving in a cylin- der. In this case the water acts by its high viscosity and power to withstand a pressure without serious loss by internal friction. The difference between these two methods is more appa- rent when it is pointed out that whereas in the first case the entire absence of weight would mean absolute inefficiency to perform work, in the second case the weight of the water 4 HYDRAULIC POWER ENGINEERING. becomes a serious obstacle to its use, and requires special care to be taken in designing certain hydraulic machinery to prevent mishaps. Although these two methods appear to be antagonistic, there is the third method requiring the water to have all the properties above enumerated. The water is caused to act by its kinetic energy, and is first subjected to a greater or less pressure, and thus caused to acquire a velocity. This velocity is then abstracted in passing through the machine, and the corresponding energy is thus applied to perform work. This is the principle on which turbines are designed. If water is allowed to flow unconfined it will not come to rest until its upper surface corresponds to a horizontal plane such as the upper surface of a canal at rest. A horizontal surface is not a flat plane, but is curved to the radius of the earth, and may be defined as that surface in which the force of gravity is the same at all points. From the above definition it is apparent that the weight of any body varies according as it is placed nearer to or further above the level of the sea. Thus a water-wheel placed on a mountain, and consuming say 20 cubic feet of water per second, will not be doing the same number of horse-powers as if it were placed at the sea-level, and con- suming the same quantity of water. If, however, the power is expended in lifting, as, for instance, in connection with a vertical mine shaft, this difference of weight is of no im- portance, as the weights to be lifted have been reduced in a like proportion. When the power is expended in crushing ore, or overcoming certain frictional resistances, the wheel will require more water on the mountain than at sea-level to overcome the same resistance. The density of water (i.e., its weight compared to that of come body bulk for bulk) is varied either by a change of temperature or by a change of pressure. In determining specific gravities of bodies distilled water at a temperature PRINCIPLES OF HYDRAULICS. 5 of 62 F. and barometric pressure of 30 inches of mercury is taken as the standard, and called unity. The weight of the body to be compared is observed and compared bulk for bulk to this standard. Thus wrought iron has a specific gravity of 7.8, or i cubic inch of wrought iron weighs the same as 7.8 cubic inches of distilled water, each taken at the standard temperature and pressure. The standard weight of water has been fixed by the Board of Trade at 62.2786 Ibs. per cubic foot at 62 F. and 30 inches barometric pressure. The greatest density of water as affected by change of temperature is found to cor- respond to 39.3 F., and at this temperature i cubic foot weighs 62.425 Ibs. As regards change of density by alteration of pressure, one atmosphere (14.7 Ibs.) of additional pressure is found to cause a reduction of volume of .00005, an< ^ consequent increase of weight of .000050002. If this reduction of volume be assumed to increase directly as the pressure applied, the reductions corresponding to the usually employed hydraulic pressures are : 750 Ibs. (3 ton) per sq. in., .00254= 4.386 in. per cub. ft. 1,500 ,, (| ton) ,, .00508= 8.772 ,, 2,240 ,, (i ton) ,, .00761 = 13.158 ,, 4,480 ,, (2 tons) ,, .01522 = 26.316 ,, 6,720 ,, (3 tons) .02283 = 39.474 Wrought iron subjected to a pressure of i ton per square inch is compressed to the extent of .000077 of its length, hence water is about three times as elastic as iron. The water employed by the hydraulic engineer is either river water or town service water, and in either case foreign substances are carried in solution, thereby altering the density. In unfiltered water small particles of matter are carried in suspension, and as these particles have almost without exception a greater density than the water, a further increase of density is encountered. 6 HYDRAULIC POWER ENGINEERING. The following are the average weights per cubic foot of different samples : River water - 62.5 Ibs. = 1,000 oz. Salt water - 64.0 Dead Sea - 73.0 ,, At a temperature of 32 F., and barometric pressure of 30 inches, water passes into the solid form called ice, and owing to the great change in viscosity is useless in this form for the purposes of the hydraulic engineer. This change of condition from the liquid to the solid is accom- panied by a change of volume and consequent change of density. The weight of i cubic foot of ice is 57.5 Ibs. An increase of pressure delays solidification, as also does absolute rest of the particles of water ; but as reduction of pressure to atmosphere and ag'tation both bring about rapid solidification, this property of retarded solidification is of no moment, as in all hydraulic appliances the water is subject to both atmospheric pressure and agitation during the per- formance of its function. Hydrostatics. The name hydrostatics is given to the study of the principles governing the conditions of equili- brium of a column or quantity of water. Pascal's Principle. Pascal discovered that if water be enclosed in a vessel and a pressure applied, as for instance by pressing on a piston in a cylinder attached to the vessel, that the pressure is transmitted equally in all directions. Thus if small frictionless pistons working in cylinders be attached to the vessel in any position or direction, and each having the same area, say i square inch, then if any one of these be pushed inwards with a force of say 10 Ibs., each of the others must have the same force of 10 Ibs. applied to it to prevent it moving outwards. If, now, two of these small pistons be connected or merged into one, consequently having an area of double the original or 2 inches instead of i, the pressure required PRINCIPLES OF HYDRAULICS, 7 is that of two of the original pistons or 20 Ibs. In the same way, if two pistons be applied to the vessel, one having an area one hundred times that of the other, then the pressure required to prevent motion of the large piston will be one hundred times that of the small piston, and vice versa. If motion is allowed to take place, the small piston will move through a distance one hundred times that of the large piston, or in other words the velocity of the small piston will be one hundred times that of the large piston ; thus, what is gained in force is lost in velocity. This principle was so well understood by Pascal at the time of his discovery (A.D. 1664) that we cannot improve upon his own clear wording. " If a vessel full of water, closed on all sides, has two openings, the one a hundred times as large as the other, and if each be supplied with a piston which fits exactly, a man pushing the small piston will exert a force which will equilibrate that of a hundred men pushing the piston which is a hundred times as large, and will overcome that of ninety-nine. And whatever m'ay be the propordon of these openings, if the forces applied to the pistons are to each other as the openings, they will be in equilibrium. Whence it appears that a vessel full of water is a new principle of mechanics, and a new machine for the multiplication of force to any required degree, since one man will by this means be able to raise any given weight, It is, besides, worthy of admiration that in this new machine we find that constant rule which is met with in all the old ones, such as the lever, wheel and axle, screw, etc , which is that the distance is increased in pioportion to the force ; for it is evident that as one of these openings is a hundred times as large as the other, if the man who pushes the small piston drives it forward i inch, he will drive the large piston backward only one hundredth part of that length." Principle of Surfaces of Equal Pressure. Whereas the above principle is entirely independent of the action of 8 HYDRAULIC POWER ENGINEERING. gravity, the one about to be discussed is a direct conse- quence of gravity. This principle states that in any hori- zontal layer of a liquid at rest the pressure is the same at all points, and the intensity of that pressure is directly propor- tional to the depth of immersion. The demonstration of this principle is very easy, as we may imagine a small cube of some substance having the same weight as water immersed at any depth, then, if this cube is to remain stationary in a horizontal direction, the forces acting upon its opposite faces must be equal. The intensity of the pressure corresponding to any depth is best ascertained by direct experiment. Pascal performed this ex- periment with an apparatus known as Pascal's vases. He used glass vases having detachable bases formed of sheet metal, which were placed in contact with the smooth edges of the vases, thus forming a water-tight joint. The vase was fixed vertically in mid-air, and the base placed in position. A fine string attached to the centre of the base passed upwards and over a pulley, and had a weight attached to its other end. The base was thus pulled upwards with a known force. On carefully admitting water to the vase, the level of the water rose until its weight produced a sufficient down- ward pressure to overbalance the weight, and so allow the escape of the water through the bottom of the vase. By noting the height of the water at the time of overbalancing, it was found that the balance weight has the same weight as a column of water having a horizontal area equal to the opening in the bottom of the vase, and a height repre- sented by the height to which the water rose in the vase. Various shapes of vases were tried, some expanding from the base, and others contracting. The result was always the same, and was entirely independent of the total weight of water in the vase, but directly dependent upon the height to which the water rose. Thus we may have a hole of say 3 inches diameter, containing a diaphragm which is pressed upwards with a sufficient force to balance a column of water PRINCIPLES OF HYDRAULICS. 30 feet high, and the pressure required is the same, whether the hole be in the bottom of a lake or a tube which contracts until its diameter is only i inch or less. Fig. i illustrates this principle. Suppose the small plugs or pistons shown in the tube to be of negligible weight and frictionless, then the pressure in pounds to be exerted on each plug to prevent motion is found by measuring the area of __ Fig. i. the plug in inches and multiplying by the corresponding height h in inches, as shown in the figure, and by the weight of i cubic inch of water. The tubes are all shown of parallel bore, but it matters nothing what shape of tube is used, nor how many contortions it makes before arriving at the plug. Taking the weight of water as 62.5 Ibs. per cubic foot, or IO HYDRAULIC POWER ENGINEERING. .434 Ibs. per 12 cubic inches, we arrive at the following values, in which h represents the height or head in feet : Pressure per sq. foot - - =/ = 62.5 //. . inch =/= -43 J 7 '- Height due to pressure/ per sq. foot = // = .oi6/>. per sq. inch = // = 2.304 /. By the above principle we are also enabled to ascertain the pressure acting against a vertical plane due to water at rest reaching any height up that plane or to some A Fig. 2. height above it. As the pressure is directly proportional in any horizontal plane to the height of water above, that plane, we may calculate the pressure corresponding to the bottom edge of the vertical plane, and represent this pressure by the length of a line p drawn at right angles to the plane as shown in Fig. 2. By now draw- ing a sloping line joining the extremity of this line to the point o, where the surface of the water meets the vertical plane, and measuring the horizontal lengths joining the plane to the sloping line, we have the pressures correspond- PRINCIPLES OF HYDRAULICS. I I ing to any levels. By adding up these pressures ascertained for narrow horizontal strips the total pressure on the plane is obtained. This is the same as finding the immersed area of the plane, say in square feet, and multiplying by the pressure P l ascertained for i square foot at a depth corre- sponding to the depth of immersion of the centre of gravity of the immersed area of the plane Area X I t l = total pressure. Principle of Archimedes. About the year 250 B.C. Archi- medes made the discovery that if bodies are immersed in .water they lose in weight, and the amount of that loss is re- presented by the weight of the water displaced. Thus any body having i cubic foot capacity when immersed in dis- tilled water loses weight to the extent of 62.25 Ibs. When once the body has passed below the surface of the water, the depth to which it is afterwards immersed makes no difference to the truth of the principle, for though by the principle of surfaces of equal pressure there is an increasing upward pressure applied to the body by the water as its immersion 12 HYDRAULIC POWER ENGINEERING. becomes greater, there is also a correspondingly increasing downward pressure. Fig. 3 is a practical illustration of this principle in a form constantly met with in hydraulic machinery. Three bodies, A, B, c, are shown partly immersed in water. A is a solid cylinder of iron, having the weight W 5 when weighed in air. When immersed, as shown, there is an upward pressure P x due to the weight of water displaced, so that if a cord were attached to the iron cylinder A to prevent it sinking, the tension in the cord would be W l - P r The body B represents a hollow cylinder of iron which is immersed to such a depth that it floats. In this case the weight W 2 acting downwards is balanced by the pressure P 2 , due to the water displaced acting upwards ; consequently W 2 - P 2 = O. c re- presents a hollow iron cylinder immersed to a depth such that the upward pressure P 3 , due to the water displaced, is greater than the weight W 8 of the cylinder. In this case W 3 -P 3 =-P 4 , where P 4 represents the magnitude of a downward pressure necessary to prevent the cylinder rising to such height that W 3 = P 3 at which the cylinder would float as in the case of B. A point worthy of consideration in connection with floating bodies is whether the body is in a state of stable or unstable equilibrium. In order to find whether the equilibrium is stable or otherwise, it is necessary to find the centre of gravity G of the floating body and the centre of buoyancy or centre of gravity O of the water displaced. If G is above O as shown in the figure the equilibrium is unstable, whereas if G is below O the equilibrium is stable. In the case shown at A the equilibrium is always stable, while in the case shown at c the equilibrium is always un- stable. The Barometric Column. The phenomenon of the barometric column was first investigated by Galileo, who found that the greatest height to which water will stand in a tube from which the air had been exhausted is about 34 PRINCIPLES OF HYDRAULICS. 13 feet. Torricelli made further experiments and also used mercury. He pointed out that for a tube of any area the height to which a liquid stands is such that the weight of liquid column in the tube is always the same, no matter what liquid is employed, and that this weight represents the pressure of the atmosphere on the area of the tube. The average pressure of the atmosphere ascertained by this method is 14.7 Ibs. per square inch. The heights to which water will stand in a closed tube for various altitudes and atmospheric pressures are : 34 feet corresponding to 14.7 Ibs. = pressure at sea-level. 31.7 13.7 = i, 880 feet. 30.6 ,, ,, 13.2 = 2,870 ,, 29-5 12.7 ,, = ,, 3,900 Theoretical Hydraulics. The first point to be con- sidered under this head is the principle of continuity of flow. If water is flowing through a pipe with any velocity, and the flow is to be continuous, the same quantity Q of water must pass any points we may choose in the tube in the same space of time. If v represents the velocity of flow, and A the cross sectional area of the tube, the quantity Q may be represented as A x v, and this is true for all points in the tube. Hence whenever there is continuity of flow we have the equation Q = Av. Instead of a tube of uniform cross section, a tube of varying cross section may be used, and consequently there will be a change of velocity. A diminution of area causes an increase of velocity and vice versa. Q = Av = A 1 v l = A z v 2) etc. Velocity due to Head. The phenomenon of water flowing when subjected to a head or pressure has been made use of from the earliest times, but the law governing this velocity was investigated by Torricelli in A.D. 1644. Torricelli announced the law that, when water is subjected to a 14 HYDRAULIC TOWER ENGINEERING. head or pressure and allowed to flow unrestrained, the velocity of the water is the same that a body would acquire in falling through a height corresponding to the head of water producing the flow. If the velocity be represented by v feet per second and the height or head of water by h feet, then v= J2gh. ^=32.2. In ascertaining the velocity of flow from an orifice in a vertical plane it is usual to take the height h as measured from the centre of gravity of the plane area of the opening. This method is not strictly correct, but for a head of three times the depth of the opening the error amounts to only i per cent., and for greater heads the error is less. If the velocity is known and it is required to find the head producing the velocity, the above equation may be written The head h is often referred to as the pressure head, and the quantity as the velocity head. 2g Although the above equation is all that is required in reference to velocity of outflow from orifices, it does not state the conditions existing within the vessel containing the water. If the vessel is of larger cross sectional area than the orifice, then the velocity in it will be less than the velocity of outflow, while if at any part the vessel is contracted so as to have a cross sectional area less than the orifice, the velocity at that part becomes greater even than the velocity due to the head. This latter condition was observed by Bernoulli in A.D. 1738. Venturi made further experiments in A.D. 1791, and observed that an increase of velocity was accompanied by a decrease of pressure in the tube or vessel below the pressure of the atmosphere. There is of course a limit to this increase of velocity, that limit being reached PRINCIPLES OF HYDRAULICS. 15 when the pressure in the tube becomes zero, or when a complete vacuum prevails. Experiments conducted on tubes having a gradually changing cross sectional area show that where the tube is large, and the velocity of flow in consequence small, the pressure in the tube rises, until if the tube becomes so large that the velocity of flow is almost ////, the pressure approaches very nearly to that of the head producing the flow through the pipe. On the other hand, when the area of the tube contracts, the pressure falls. If these pressures and the corresponding velocities are noted, it is found that the amount by which the pressure falls below that due to the head is the amount of pressure head necessary to produce the velocity occurring in the tube. Written as an equation h-h , = -1-, mh = h l +^ 2 *S *S As this is true for any part of the tube, the equation may be written // = ^ + *i=J + !!*?, etc., 2g 2g which is known as the hydrodynamic equation. The Energy of Water. There are three ways of expressing the energy of a quantity of water. In the first place, the water may be stored at a height above the level at which it is to be employed to perform work, the energy existing in the potential form. In the same way that, if a heavy body be sustained at some height, its potential energy may be expressed in foot-pounds by multiplying the weight of the body in pounds by the height in feet, so the potential energy of water may be expressed W// = potential energy. Instead of the head being given, it is often stated that the water is at a certain pressure per square inch. In this case the energy per pound may be expressed by multiplying the 16 HYDRAULIC POWER ENGINEERING. pressure per square inch by the length in feet of a column of water weighing i lb., and having a cross sectional area of i inch. Suppose a cylinder of i square inch area to contain a piston which is driven forward by water under a pressure / pounds, when the piston has moved forward 2.304 feet, i lb. of water has passed into the cylinder, and the work done is represented by /x 2. 304 foot-pounds. Thus the pressure energy of i lb. of water is / x 2.304 foot-pounds or for any weight of water W x/ x 2.304 = pressure energy. It has already been pointed out that the height // due to a pressure / pounds per square inch is 2.304^ feet. Therefore Wh =Wx/x2.304. Potential = Pressure energy. energy. The third expression for the energy of water is used in the case of flowing water. It is well known in connection with falling bodies that the energy stored in the body in the kinetic form, due to the body having fallen freely from some known height, is ascertainable from the velocity acquired by the body in falling, and is represented by the equation W = kinetic energy. 2 S It has already been stated that the velocity acquired by water under a head h is the same as that of a body falling freely through the distance //, hence the kinetic energy of a weight of water W is ascertained from its velocity by the above equation. By the principle of the conservation of energy, the potential energy must equal the kinetic energy, or WA = W , # which is easily proved since v 1 = 2gh, as already pointed out under Velocity due to Head, PRINCIPLES OF HYDRAULICS. I/ If an inspection be now made of the hydrodynamic equation, we see that by multiplying each side by W the equation becomes From the equation in this form it is noticed that the Fig. 4. energy may occur partly as potential energy and partly as kinetic energy, or partly as pressure energy and partly as kinetic energy, as \Nh l may be written W/ x x 2.304. It is very important that this fact should be grasped at this stage, as there are very few hydraulic machines in which the energy does not occur in this form while the machine is at work. The relation existing between the different forms in which 13 1 8 HYDRAULIC POWER ENGINEERING. the energy may occur can be rendered more clear by an examination of the working of the hydraulic pump, com- monly known as the hydraulic ram, illustrated in Fig. 4. The object of the apparatus is to pump water to a consider- able height by utilising the potential energy of a supply of water placed at a smaller height. At the joint A connection is made to a length of pipe, usually 10 to 20 feet, leading to the supply of water to be utilised. Connection is made at c to the receiving tank to which the water is to be pumped, so that the air contained in the bell F is com- pressed to a pressure corresponding to the head of water connected to G. When the valve B is shut the water in the pipe A is stationary. The weights c applied to the valve B are sufficient to overcome the pressure in the pipe A and thus cause the opening of the valve. The water now begins to acquire a velocity and escape through the valve B, thus converting the whole or part of its potential energy into kinetic energy. As the water escapes through the valve B it meets the guide D and is deflected, causing an upward pressure on the valve spindle sufficient to overcome the weights c and close the valve. The water in the pipe- A, having a velocity and corresponding kinetic energy, is now entrapped in the pipe, and as this energy cannot be dis- sipated and cannot continue wholly in its present form, as the velocity of the water has been checked, it is evident there must be a conversion of energy to the pressure form. This conversion causes a heavy pressure to be generated in the pipe A, and when this pressure has risen above the pressure in the chamber F the ball valve E will be raised, and water will flow from A to F as long as the pressure is maintained in the pipe A greater than the pressure in F. During the entry of the water from A to F the pressure in F is increased owing to the compression of the air. This increase of pressure overcomes the pressure acting at G, and there is a consequent flow through G to the elevated PRINCIPLES OF HYDRAULICS. 19 tank. On the closing of the valve E the pressure in A again returns to that due to the smaller head, and the valve B is free to be operated by the weights c causing a repeti- tion of the operation. Thus we have converted potential energy to kinetic, kinetic to pressure, and pressure to potential energy. The Reaction of Flowing Water. When water is flowing from an orifice with a velocity due to some head of water, we have noticed that the velocity v is the same that would be acquired if each particle started from the upper surface of the water and fell freely under the influence of gravity. It is possible to calculate the magnitude of a force F which, acting for one second on the weight W of water flowing per second, would cause it to acquire the velocity v. As F acts for one second the distance through which it acts is \v, and the equation may be written tJJ The expression W- will be at once recognised as the usual formula for momentum. As W may be written war, in which w is the unit weight of water and a the area of the orifice, the formula becomes -r. wav' 2 v' 2 v = = 2wa. in which may be substituted by //, so that F= 27i>ah. As wah represents the weight of the column of water producing the velocity, the force F is equal to twice the weight of the column. Several experiments have been performed to demonstrate 2O HYDRAULIC POWER ENGINEERING. the above fact. In one form the jet of water is allowed to meet a plane, when the plane is urged away from the jet with the force F as above calculated. In another form the plane is placed against another orifice subjected to a head of twice that producing the jet, when it is seen that the jet retains the plane in position, thus keeping back the greater pressure by the reaction force F. CHAPTER II. THE OBSERVED FLOW OF WATER. THE remarks upon the flow of water in the last chapter had reference to the theoretical velocities, and no allowance was made for loss by friction and other causes. These losses must now be investigated before the formulae there given can be successfully applied to the design of hydraulic machinery. Fig. 5- The attempt to ascertain the exact quantity of water flow- ing through an orifice has been the cause of a large number of experiments being performed. Fig. 5 shows the orifice as usually arranged, the edges being chamfered off so as to produce a sharp line in contact with the water. The orifice may be cut in a piece of hardwood or in thin metal, As 22 HYDRAULIC POWER ENGINEERING. these orifices are largely employed in accurately measuring the water flowing from a hydraulic machine under trial, and for other similar purposes, it is essential that some standard should be fixed in order that the exact quantity of water flowing per second may be computed from tables compiled from well-authenticated experiments. It is found that if the inner edge of the orifice is rounded off, the flow is subject to alteration for a comparatively small difference of form, hence the sharp edge is always employed. In using an orifice the vessel should be considerably larger than the orifice, in order that the velocity of approach may be small compared to the velocity of discharge. For the same reason the head should not be too small. As the water issues from the orifice a contraction takes place, known as the contracted vein, so that the effective area of the orifice is less than the measured area. The values of the coefficient of con- traction have been assigned by different authorities as ranging between .71 and .60, generally .63, of the measured area. The velocity of flow at the contracted area a, Fig. 5, should be the velocity due to the head, but owing to frictional losses it falls to values of .99 to .97 of the theoretic value. These values are called the coefficients of velocity. The most important point to settle is the coefficient of discharge ; the quantity of water actually flowing can then be ascertained by multiplying the quantity due to the area of the orifice and the theoretic velocity by this coefficient determined the thickness T of the cylinder D Fig. 12. in the ordinary way, and then clapped on the passage d without considering the effect of the addition on the stress 42 HYDRAULIC POWER ENGINEERING. on the metal between the cylinder and passage that is at A. Thus, if P be the water pressure, the stress on the D metal at A is -XP, while at B it is only - X P. 2 T 2 r l Hence if the metal at B be properly proportioned to with- stand the pressure P, the metal at A is decidedly too weak, and its thickness should have been T + /, as indicated in Fig. 12. Fig. 13 similarly illustrates a faulty and a correct method of making the inlet-pipe connection to the side of a high- Fig. 13. pressure cylinder. A is, of course, the correct construction, and B the faulty one. At B a large hole for the reception of the inlet nipple has been drilled and tapped, and only reinforced by a shallow boss, and, in some cases which have come under our notice, by no boss at all. At A only the comparatively small and necessary inlet hole penetrates the barrel of the cylinder, and the strength of the metal thus taken away is amply supplied by the substantial boss into which the inlet nipple is screwed. Such faulty constructions as those illustrated by Figs, n and 13 may stand the test pressure, and work without failure for a considerable time, HYDRAULIC PRESSURES. 43 or, indeed, if there be ample material, may outlive the machine. On the other hand, if the thickness of the metal be originally somewhat inadequate, or the machine over- stressed through some accidental cause, weak points have been provided by the designer at which fracture may com- mence, causing, possibly, groat loss and annoyance, and resulting simply from the want of a few pounds of metal in the right place. The construction illustrated at B is espe- cially faulty owing to the intense stresses liable to occur at the edges of the nipple hole, owing to the break of con- tinuity of the metal and consequent localisation of strain. If, however, cast-iron cylinders be well and properly designed, cast from a suitable blending of metal, and with proper care on the part of the founder, they may be used with confidence for pressures up to 2 tons per square inch ; and for thoroughly steady loads, such as those obtaining in the case of ordinary presses used in the compression of yielding and elastic substances, a pressure of 3 tons per square inch is not inadmissible. CHAPTER IV. MATERIALS. THERE is, in general, no true economy in the employment of inferior metal in the construction of parts of machines in which great strength is required, since the loss of strength due to the inferior quality of the metal is far from com- pensated for by a slightly diminished first cost of the machine. In low-pressure hydraulic machines the thickness of the castings is frequently dictated by the exigencies of manufacture, and not by the working stresses to which they are subjected; but in the case of cylinders of medium pressure, and still more so in the case of the cylinders of high-pressure machines, which are frequently worked up to their full test pressure, or say one-half their probable initial breaking load, metal of first-class quality should invariably be employed. The cast iron for such purposes should be of at least such quality that a test bar i inch square, cast on end, will not break with a tensile load of 9 tons, and a bar i inch by 2 inches, placed on edge and carried by supports 3 feet apart, should sustain 30 cwt. in the centre without fracture. The metal, when cast into the actual shapes in which it is used, will in general have a considerably lower resistance to fracture than that of the test specimens, and it will not be wise to exceed a test stress on the metal of the complete machine of say 3^ tons per square inch. With respect to the working stress and factor of safety, as it is commonly called, we shall have something to say further on, as also as to the peculiar and dubious character of the stress sustained by thick cylinders under internal fluid pressure. MATERIAL. 45 With regard to wrought iron, there is little to be remarked having special reference to hydraulic work. When used for cylinders, it must of course be thoroughly sound, and should not be designed for a higher test stress than 8 tons per square inch distributed, and if the thickness of the metal be considerable a lower stress may be advisable ; a point we intend to discuss further on. For rolled Staffordshire bars of fair quality, a test stress of 10 tons per square inch is not too high, if applied in simple direct tension. Steel is a material which has only lately come into general use for hydraulic cylinders, but the success which has re- warded the efforts of the steel-founder in the production of thoroughly sound and reliable steel castings is causing steel to rapidly replace cast iron in the construction of cylinders for high pressure?. The breaking strength in tension of the metal employed is usually stated at 24 tons per square inch, but this is not probably obtained in the actual cylinder casting, the test stress on which it will be well to limit to 8 tons per square nch for cylinders of moderate thickness. For sound hammered steel cylinders, or hydraulic forged, a test of 10 tons per square inch of metal will not be too high. Solid drawn steel tubes forms an excellent, indeed the best material available for high-pressure hydraulic tubes. For the rams of hydraulic presses and hoists, rolled or hammered steel is frequently used, and sometimes steel castings, but there is a difficulty in getting the latter sufficiently sound on the surface for use in high-pressure work. Indeed, even in the case of hammered steel it is necessary to allow ample metal in the forging to permit of a substantial first cut being taken off over the surface (the rough should be at least f inch larger in diameter than the finished ram), as otherwise it is impossible to eradicate the unsoundness due to the surface blowholes invariably found in the ingot. These, although closed in by the subsequent hammering, which leaves an apparently sound face in the finished use, are not really welded up, but reappear in the 46 HYDRAULIC POWER ENGINEERING, shape of an unsound surface on the first cut being taken off in the lathe. Malleable cast iron, toughened sometimes by the addition of a little scrap steel, is used with success for small short cylinders. Its ultimate strength, i inch thick, does not exceed in general 15 tons per square inch, and for \ inch thick about 20 tons per square inch. The test stress may be taken at 8 tons per square inch, if the metal does not exceed f inch thick. It is, however, a treacherous material, very liable to unsoundness, and should only be used for small and unimportant work. The alloys of copper, tin, and spelter are of the greatest importance to the hydraulic engineer, owing to their freedom from corrosion by water. Hence they are used almost to the exclusion of any other metal for barrel linings, plungers, valves and valve seats, screwed caps and plugs, etc. Brass also forms an excellent sheathing for the outside of rams, and its use for that purpose is highly conducive to the durability of leather packings, while in all cases in which a cylinder is bored to receive a leather-packed piston it should also be lined with brass or gun metal, unless there be special circumstances which militate against their use. For the smaller class of pumps gun-metal castings are almost ex- clusively employed. The castings so used are in general somewhat, but not greatly, tougher and stronger than good cast iron. A test stress of 4 tons per square inch of metal may be permitted for gun -metal pump barrels. For hydraulic pressures exceeding 4 tons per square inch steel should be used in place of gun metal. The portion of the brass foundry occupied in the production of hydraulic castings should be separate from that in which the commoner descriptions of iretal are cast. Very annoying inequalities in the strength and closeness of the metal, due either to carelessness or wilful neglect on the part of the workmen, are otheiwise extremely liable to occur. For pump plungers the rolled alloys, such as Kingston metal MATERIAL. 47 and rolled phosphor bronze, are very reliable. These and similar alloys, in the form of rolled rods and solid drawn tubes, can now be procured of the strength of steel, and at very moderate prices. Phosphor and manganese bronze castings are also used for pump barrels, and are said to have an ultimate breaking weight of about 19 tons per square inch of metal, but as far as the author's experience extends this cannot be depended on in the actual castings. The test stress for phosphor bronze pump castings may be taken at 6 to 7 tons per square inch of metal. Rams are coated with copper by electro-deposition by the Broughton Copper Company, of Manchester, and other firms, at very moderate cost. The finished thickness of copper usually supplied is ^V inch. The durability of the sheeting so formed can be relied on, and its great gain in the first cost, as compared with brass sheathing, has brought this plan into favour. Leather and one or two other materials of special utility for hydraulic work will be dealt with in connection with their applications. Having considered the safe test stresses of the materials employed in hydraulic work, we have now to consider the not less important question as to what proportion the actual working stress should bear to that stress. Very hazy notions on this subject have been held up to recent times, and, indeed, are still held. Great importance used to be attached to the determinations of the so-called "elastic limit" of a material, by which term was intended that stress at which the metal began to take noticeable permanent set. It was demonstrated by Mr Hodgkinson, however, that cast iron had no definite " elastic limit." By expetiments with long cast-iron bars (15 feet long) he showed that cast iron takes a permanent set with small loads, increasing gradually, as the load is increased, up to the breaking point. Ductile wrought iron and mild steel have, however, a definite "elastic limit" of stress, or rather 4 8 HYDRAULIC POWER ENGINEERING. they have a definite "breaking-down" point. This will be better understood by reference to the annexed diagram, Fig. 14, which represents the extension of a mild steel bar, i inch square, 10 inches long, under loads progressing in strain up to the breaking point. The author has carried out a very large number of experiments with mild steel bars, and /A/ Fig. 14. has invariably found the stress and strain diagram (drawn automatically by the bar itself) to have the characteristics illustrated by Fig. 14. From o to A the extensions of the bar are very nearly proportionate to the stress applied ; in other words, they follow Hook's law /// tensio sic vis. A is the true elastic limit. From A to B is a transition stage ; MATERIAL. 49 the extension is no longer proportionate, but increases more and more rapidly. The extension between o and A is a very minute portion of the length of the bar, and is exag- gerated in the diagram so as to make it capable of represen- tation. When the stress reaches the amount indicated by the point B, the bar extends without increase of load a distance of |- inch or more in a specimen 10 inches long it, so to speak, " breaks down." Hence B has been termed the " breaking-down point " of the bar. The " elastic limit," as ordinarily found by the aid of a pair of dividers, may be anywhere between A and B, or even below A. The specimen now extends from B to c without increase of load. In diagrams taken with apparatus of too sensitive a nature in the writer's opinion to be reliable, and also in diagrams taken by apparatus in which the load on the specimen is measured by the water pressure in the hydraulic cylinder of the testing machine, the line B c appears as a jagged line. There can be little doubt, however, that these apparent fluctuations in the load in the specimen are due mainly to imperfections in the recording apparatus, owing to the rapid stretch of the specimen from B to c. With well designed apparatus in which the actual load, as measured by the dead-weight lever, is recorded, the line between B and c is found to be almost, if not quite, straight and horizontal. c is usually a very well marked point, from which the extension of the bar increases very rapidly with increasing load. At D the maximum load which the bar can sustain without immediate fracture is reached. From D to E the load on the bar materially diminishes, until the bar, having stretched to E, suddenly breaks. The whole subject is a very interesting one, but since we are concerned not with the behaviour of metals under test, but with their use in hydraulic machines simply, we must be brief. Our present object is to point out that the so-called " elastic limit " is not in itself a quantity of much importance, D OK TT-M-TVFVRSITT 50 HYDRAULIC POWER ENGINEERING. since it can be raised at pleasure. For instance, if the bar, the behaviour of which under test is illustrated by Fig. 14, had been subjected to a preliminary load of 22 J tons, we know by the results of many experiments that, on being subsequently tested, its "elastic limit," instead of being about 1 8 tons per square inch, would have been found to be more than 22 J tons to the square inch, and no such stage as that between B and c would be observed. Hence a steel or iron master, who has to do with an engineer who has great faith in a high " elastic limit " as a measure of the strength of a bar and there are such engineers has merely to watch his opportunity and apply a stress equal to the proscribed " elastic limit " before the inspector commences his test, and he will be sure of the bar passing the test as far as regards the "elastic limit." Not only can the "elastic limit" be raised; it can also be lowered by manipulation. By compressing a bar of wrought iron endways, powerfully, its " elastic limit " may be reduced to as little as 5 tons per square inch without affecting sensibly its ultimate breaking weight. Hence we must discard the "elastic limit," at any rate taken by itself, as in any way measuring the value of the bar for constructive purposes. In comparing the quality of two bars, it is necessary that the specimens should be of equal length and equal diameter. The important points, then, to be observed, as determined by tests, are the ultimate breaking weight and the ultimate extension. Having thus disposed of the claims of the "elastic limit" to be considered as a basis from which to determine the relation between test straps and working stress, we have next to consider from what sound basis their relations may be determined in the special case which we have to consider, viz., that of hydraulic power machinery. CHAPTER V. TEST LOAD. HAVING disposed of the pretension of the so-called "elastic limit" to be considered an indication of the safe working load of a bar of wrought iron or steel, we have now to point out another fallacy, which has a deep root in the minds of many. It is a common belief that if a piece of metal- or a machine pass its "test" without giving signs of undue strain by taking permanent set for instance, in the case of a bar stressed in tension, or, as in the case of a hook or a punching machine, by a permanent springing open of the jaw that it is quite safe for any number of repetitions of the test load. Some early experiments of Sir Wm. Fairbairn went to show the fallacy of this error in the case of riveted girders, but were too crudely conducted to be conclusive. More re- cently, however, the researches of Wohler and Spangenberg have thrown a flood of light on the subject. It appears from their experiments that the breaking weight of a piece of metal depends not merely on the absolute magni- tude of the stress per square inch, but also on the frequency of repetition and the range of variation of the stress. The experiments, though very extensive and amply conclusive as to the general results, were not conducted with sufficient care to suggest an exact formula ; but the general nature of the results will be readily understood by considering the breaking weights, as determined from them, of a bar of wrought iron loaded either by (i) a steady load applied con- stantly ; (2) a steady load applied and removed alternately an indefinite number of times ; (3) a steady load applied 52 HYDRAULIC POWER ENGINEERING. alternately in opposite directions that is, alternately com- pressing and extending the fibres. The breaking weight in the first case is 20 tons per square inch, in the second 13^ tons, and in the third 6 tons per square inch. Thus the breaking weight in the three cases have the proportions 3 : 2 : i, or i : f : -J. As an example of the first case, we may instance the links which connect the balance-weight chain of a slow-moving hoist to the cage or to the balance weight. As an example of the second, the columns, head, cylinder, etc., of a hydraulic press ; and as an example of the third, the piston rod of a steam engine, or the spindle of an overhead pulley of a hoist. What is known as the Dynamic Theory of Loads is now largely accepted by leading engineers, more especially in connection with bridge design. The theory states that if a load be applied quite suddenly the strain produced is double of that which would result from the application of the same load very gradually ; also if a load be suddenly re- moved, and applied in the opposite sense, the resulting strain is three times that which would result from the removal of the load and application of the reverse load very gradually. In treating of the safe working loads, as determined from the test stress, we shall in all that follows suppose that the metal is stressed in one direction only, but that the stress is applied and removed continually in the ordinary working of the machine. If the stress be alternately applied in oppo- site directions, one-half the working load, as determined by the following considerations, must be taken as the safe working load. We may divide working loads roughly into four classes (i) Perfectly steady loads ; (2) ordinary loads, not perfectly steady, but nearly so, and perfectly steady loads applied to machines in which failure would involve considerable loss or annoyance; (3) loads applied with more or less but not excessive shock ; (4) loads in which failure must result in danger to life or limb. TEST LOAD. 53 As types of the first class of loads may be taken hand- worked hydraulic presses operating on yielding materials. Here we have the class of stress most favourable to the life of the machine, and the working stress may be four-fifths the test stress. Hydraulic punching bears and hydraulic jacks, and similar small tools will also fall under this head, and may be worked up to four-fifths their test stress if otherwise properly proportioned. Indeed, machines of this class are often worked up to their full test load. As types of the second class may be taken large hydraulic baling presses worked rapidly and frequently, high-pressure hydraulic accu- mulators, fitted with safety valves, and high-pressure work in general ; for this class the working load may be two-thirds the test load. Medium-pressure hydraulic work, in which the load is very steady, may also be included in this class. As types of the third class may be taken medium-pressure hydraulic hoists, accumulators, etc., chain hooks and similar parts, and medium-pressure work in general, for which the working load should not exceed one-third to one-half the test load, according to the degree of shock incidental to the working of the machine. For the fourth class, which is in- tended to cover such work as hotel lifts, etc., the working load should not exceed from one-fourth to one-fifth the test load abundant strength being specially provided in all parts liable to deterioration or wear. If frequent skilled supervision cannot be guaranteed, a still larger margin should be allowed. Gun-metal high-pressure hand pumps may be worked up to two-thirds the test pressure. Gun-metal high-pressure pumps driven by steam cylinders direct, or by belt, may be worked up to half the test pressure, or, if of cast iron, up to one-third the test pressure. Table I. gives the test stresses and working stresses suit- able for the materials most frequently used in hydraulic machinery, and the proper proportion of working load to test load. X^uipao aS o 2 CO vo co Th moo t~> vo in ir M vo IN n 3 ^ in *- 4- CO N " ^ UBUIpJO . . . & ' ^ c 3 O ,3.0 N -^- ro - R vO IN vo M M VQ N N * n O * !- C/2 O Z ^ 00 ro VO vo' vo M in ~J ir O HLl .^o ^ VO * O tr* ' ' * > ^HXO OO ^*" '_ in 00 -<1- ro vo csi B O .^o ^ - t " t . VO o " ?" rt co t in -1- ro VO M " ^ m vo 1- ? * ? \ ~ r) - (/ - /j) lesg than the fraction r i ~ r Hence the r + t r tension on the fibres of the external circumference is less than that on those of the internal circumference, and the former do not take their fair proportion of the work of resisting the disruptive effect of the internal pressure.* Lame was the first writer to accurately determine the effect of this inequality of stress throughout the thickness of the cylinder on the supposition of extension being directly proportional to stress. He obtained the formula P ( R^ -I- j'*} f= ~ ', where / is the tension at the internal cir- K." T" cumference, P the internal pressure, R the external radius, and r the internal radius. We have omitted from the formula the term involving the external pressure, since, in such cases as we are concerned with, the external pressure will, in general, be comparatively very small. The steps by which this result is arrived at may be consulted in Lame's " Traite de I'Elasticitd," or Ibbetson's "Theory of Elasticity," or Rankine's " Applied Mechanics," the result obtained being the same in each. The formula may also be put in this form :/= -,. T R -r- r where T is the thickness of the cylinder, P and /may be taken in tons or pounds per square inch, and R, r and T in inches, or any other units of length or weight at pleasure, provided the same units be used for P as for/, and the same unit for T as for R and r. * The above must not be taken as an exact statement of the true conditions of stress and strain throughout the metal of the cylinder, as we have not taken account of the effect of the radial compression on the relations of stress and strain, but simply as an approximate illustra- tion of the necessary variation of the strain throughout this thickness. TEST LOAD. 57 If R be nearly equal to ?-, we obtain the usual formula for the tension on the metal of a thin cylinder, viz., Professor Pearson (see footnotes pp. 550 and 552 of Todhunter's " History of Elasticity ") considers that Lame's formula for the strength of a thick cylinder errs on the side of assigning too high a value to the strength of the cylinder. The author does not, however, consider this conclusion to be confirmed by experience. On the contrary, we know that the actual materials in construction do not follow Hooke's law in their extension with precision, and there is, so to speak, a sort of "give-and-take" action, which tends to cause a greater equality of stress throughout the thickness of a cylinder than Lame's formula would indicate. On the other hand, however, the internal circumference of the cylinder in the case of castings is usually the most un- sound, owing to the exterior of the cylinder cooling first, and the inner rings of metal later, while at the same time it is the part most severely stressed in actual work. The plan of circulating water through the core bar, as adopted in America in the casting of ordnance, may be employed with advantage in the case of important hydraulic cylinders, to ensure soundness in the inner layers of cast-iron cylinders. On the whole, the author considers it better to be guided by the results of successful practice in assigning the test pressure for hydraulic cylinders, rather than by a formula based on a defective theory. Tables I. and II. exemplify his own practice, and have been used successfully in fixing the dimensions of many hundreds of hydraulic cylinders. For low-pressure work, the following dimensions may be adopted for pressure (test) not exceeding 500 Ibs. per square inch : Inside diameter in inches .... 3 3\ 4 5 6 7 9 10 ii 12 13 14 1C 16 17 18 20 22 24 2628 1 Thickness in inches 1 A 1 1 i|4i 1 1 I 1; i i I I I I .4 HYDRAULIC POWER ENGINEERING. TABLE II. THICKNESS IN INCHES OF CAST-IRON CYLINDEUS FOR TEST PRESSURES OF Inside Diam. Ins. Lbs. per Square Inch. Tons per Square Inch. 2f 3 800 I OOO I 2OO 1.500 I ii Ii '4 a 2 2i 2i 3 I i i i 1 Ii I| I| ii ii 2 3* & i '2 i 1 3 4 i I I 4 If ii ii 2i 2i 4 i i i 1, I i ii I* ii ii 2i 2| 2g 5 i -A g 2 I ii if ii ii 2i 2j 2i 3i 6 $ 8 i 2 Ii ii if 2 2i *l 3 3^ 32 7 T 9 ,T a 2 i Ii ii ii 2i 25 3 3i 3i 4i 8 T 9 ,T 2 i i If if 2 2* 2.1 3l 3i 4i 4i 9 1 2 x ii 4 ii 2* 2? 3i 3i 4i 4i Si 10 i i ii If 2i 2i 3 3^ 4i j 4i J^ 6 ii I i i 'i If 2k 2| 3i 3i 48 5i 6 68 12 i i ii i| 2 2\ 3 3 4i 5 | 54- 6i 7i 13 5 i T i 1 4 ii 2| 2? 3i 3i 4i 5S 6i 7 72 14 I ii I4 1 4 2 i 23 31 4i 4i 5f 6i 7i 8i 15 I ii 13 ii 2| 3 31 4i 5l 6i 7i 8 83 16 I ii I '2 if 2i 3* 3i 42 5i 6i ?i 8J 94 17 18 Ii I* ii ii Ii ii ii 2 28 2? 3l 38 4i 4g 5 53 Si 6i 7 7i 8 8| 9 9i 10 ioi 20 Ii ii i2 2i 3 3i 42 5i 61 84 9 iog ni 22 If IH : i 2| 3l 4i 51 6f 7i 81 ioi ni I2i 2* If i 2i 2i 3i 4* 5J 7 8i 9'i ni I2| 14 26 I* ii 2i 2| 3-5 Si 6i 7g 8i io| 12 3i i5i 28 I| 2 2| 2i 4i Si 6| 8i 9^ ni 13 148 i6i 30 J 2| 2| 3i 4* Si 7i 8| roi M* iji si i7i TEST LOAD. 59 TABLE III. THICKNESS OF STEEL CYLINDERS (UNHAMMERED CASTINGS) FOR TEST PRESSURES OF Inside Tons per Square Inch. Diam. Ins. 1 '* Ii if 2 21 2.' 2| 3 3i 4 5 3 i ii ii j_ ii ll -i 4 i " n ii 1 ? if 18 T^ c I ii II 4: * 8 2 J 6 I Ii 8 ii ii If ii 7 ... ... i ii Ii ii ii If .ii 2i 28 8 I ii ii ii ii if If 2i 2i 3 9 I ii ii if if if ii 2 2 28 3i 10 ... Ii ii if ii i? ii 2 2i 2i 2| 38 ii i ] ii ii ii if _ 2 2l 2| 2| 3i 4 12 i ii if ig ii 2 2| 2f 22 3 3i 4i 13 ii ! ii ii ii 1 7 1 IS 2i 2f 28 2| 3i 3i 48 14 ii ii if ii 2 2l 2i 2| 2i 3i 4 5 IS ii ii i! 2 2i 2f 2f 2i 3i 3S 4i Si 16 ii ii ii 2 2i 2-V 2? 3 3i 3i 4i si 17 i3 ig i| 2i 2f 21 3 3i 3i 4i 42 6 18 ii if 2 2l 2-i 2< . 38 4f 5 i 61 20 4 ii 2i 2* 23 Si- 3i 3l 4 4i 5i 7 22 I ^ 2 2f 2i 3 Si 31 4 4f Si 6 78" 24 If 2j 2- I 2i 31 38" 4 4i 4-1 5S 64 81 26 Ii 2f 2 : 1 3i 3i 4 4i 4l Si 6i 7i 9 28 2 2$ 2| 3f 35 4i 48 Si Si 6f 78 91 30 2i 28 3i 38 4 4i 5 5 " Si 7 8i ioi 6o HYDRAULIC POWER ENGINEERING. A few remarks may be here appropriately introduced on certain points in the design and construction of high-pres- sure hydraulic cylinders of these materials, non-attention to which will frequently result in failure and disappointment. In the first place, the internal corners at the bottom should be struck to a large radius, as shown by Fig. 16 ; and if the cylinder be cast with a solid bottom, the interior of the bottom should be struck to a radius not exceeding the diameter of the cylinder in length. A good practical rule is to make the corners one-fourth the internal diameter of the +T+ & Fig. i 6. r-V-il llli : = IIS _-=-s'-r;- liil;! i^^^^ Fig. 17. cylinder in radius, and the bottom three-fourths the internal diameter of the cylinder in radius. If these proportions be adopted, the thickness of the bottom of the cylinder will be sufficient if made equal to that of the walls, as illustrated by Fig. 1 6. In the case of long cylinders, in which it is neces- sary to carry the core bar through the bottom in order to provide a support for its end, the same proportions may be adopted, simply inserting the necessary plug for stopping the hole left by the core bar. The necessity of a large rounding of the corners arises from the fact that if they be left nearly square (see />, Fig. 1 7), TEST LOAD. 6l the crystals of the casting arrange themselves during cooling in such a manner as to invite fracture along the line a b (Fig. 17), and unless the cylinder be constructed of a thick- ness unnecessarily great for the pressure to which it is sub- jected, deterioration gradually goes on along the line a /;, until sooner or later failure takes place, as illustrated by Fig. 1 8 ; and a conical piece A breaks away from the end of the cylinder. F'ig. 19 shows the arrangement of crystals in a cylinder with a curved bottom of equal thickness to the sides. Fig. 18. Fig. 19. Fig. 20 illustrates a properly-designed cylinder, and simi- lar to Fig. 1 6, but with a plug inserted by driving from the inside. This method is found amply sufficient for cylinders of diameters ranging to 10 inches or 12 inches inside, or even more. For larger cylinders, the method illustrated by Fig. 21 may be adopted, in which the plug is made tight by means of a U leather and back plate. The sources of weakness to which attention was drawn in Chapter III. should also be carefully avoided, and it is also in general advisable to construct high-pressure hydraulic cylinders in the form of plain cylinders, as the castings are 62 HYDRAULIC POWER ENGINEERING. less likely to suffer from unequal contraction, and the risk of unsoundness due to "drawing" at the junction of ribs, arms, lugs, flanges, etc., is avoided ; also the cylinder is then more readily replaced, and at less cost, if found de- fective. Very considerable deviation from this rule may, however, be made without incurring undue risk, if proper skill be possessed and employed by the designer and founder. In the second place, supposing the cylinder skilfully designed and of adequate proportions, the two great essen- Fig. 20. tials required to ensure soundness in the casting are, firstly, the metal shall be of close texture, otherwise, though amply strong enough to resist the stresses due to internal hydraulic pressure, the casting will fail from its permeability, and under intense pressure the water will ooze through the metal. Also, from the examination of cast-iron cylinders, which have been ruptured in ordinary work, although ap- parently of adequate strength to resist the pressure to which they have been subjected, the author has been led to con- sider it probable that a partial permeation of the metal by the water may result in a higher intensity of stress on the TEST LOAD. internal layers of a cylinder than would be due to the pressure of the water within the cylinder; and hence a cylinder may be erroneously considered to have failed from Fig. 22. Fig. 23. deficient thickness of metal, when the failure has really resulted from porosity in the casting. Thirdly, it is necessary that a " head " of ample dimensions Fig. 24. should be cast on the end of the cylinder which is upper- most in the mould (usually the bottom of the cylinder in actual work). This head should not only be of sufficient 64 HYDRAULIC POWER ENGINEERING. depth to produce adequate fluid pressure on the casting, but also of sufficient bulk, in order that it may remain fluid longer than the body of the cylinder, and thus maintain a pressure on the metal during the whole period of solidi- fication. Hence, to be effective, the head should take the form illustrated by Fig. 22 or 23, and not that illustrated by Fig. 24, which is ineffective and irrational, though not unfrequently adopted. If due attention be paid to the points here briefly dis- cussed, the thicknesses given in Tables II. and III. will be found amply sufficient for the test pressures there stated. Having thus cleared the ground by defining the meaning to be assigned to tests and working pressure and stress, and their proper relative and absolute values for the various mate- rials employed in the construction of hydraulic machinery, we are now at liberty to discuss the proper proportions and design of the details and component parts of such machinery. PART III. JOINTS. CHAPTER VI. PACKINGS FOR SLIDING SURFACES. THE packing by means of which the rams, pistons or plungers of hydraulic machinery are enabled to slide to and fro at the same time that the passage of fluid past the slid- ing surfaces is prevented, may be divided into two classes, viz., firstly, that in which the packing is self-acting that is, Fig. 25. maintained in water-tight contact with the sliding surface by the simple action of the hydraulic pressure itself; and secondly, that in which the tightness of the packing is dependent on mechanical compression by means of glands or junk rings, as in the case of stuffing boxes. Fig. 26. Fig. 27. Fig. 28. Of the first, or self-acting class of packing, the simplest is the spiral leather packing (Figs. 25, 26, 27, and 28). This is a very excellent packing for small plungers and pistons. It consists simply of a strip of supple leather y\ inch or 68 HYDRAULIC POWER ENGINEERING. inch wide, and of sufficient length to wrap round the plunger three, four, or five times (Fig. 25). Fig. 26 repre- sents the plunger without the packing, Fig. 27 the packing in course of being wound on, and Fig. 28 the plunger packed and ready for use. The operation of packing a Figs. 29 and 30. plunger in this manner is apparently very simple, but yet requires a certain amount of skill and practice to perform it with speed and neatness. The strip of leather must first have one end cut with a sharp knife to an acute angle. It must then be tried in the groove of the plunger, and shaved PACKINGS FOR SLIDING SURFACES. 69 if necessary down to the proper thickness to just fill the groove up to the required working diameter which will fit the pump barrel tightly. It is then wrapped round the plunger, and the free end chamfered off to a gradual taper and length to just fill the length of the groove. The free end is then hammered into the unfilled portion of the groove with the handle of a screwdriver or file, and the plunger is ready for use. This description of packing is only suitable for small plungers not exceeding i inch or i| inches diameter, but is Fig. 32. a very simple, cheap and durable packing for such small work, and is perfectly reliable and water-tight at even the highest pressures. The most simple self-acting packing for rams, pistons and plungers, next to the spiral leather packing previously described, is the cup type of packing, which is constructed in three forms, commonly termed cup, hat and U packing respectively. The cup packing is illustrated by FigSc 29 and 30, and simple tools for and the process of manufacture by Figs. 31 and 32. The cup packing is used as a packing for pistons, for 7O HYDRAULIC POWER ENGINEERING. ..< making water-tight joints at the ends of plugs and plungers, and similar purposes, and owes its self acting tightness to the pressure of the water on the internal surface of the cup, which expands the rim of the cup and forces it against the pump barrel or other surface with which water tight con- nection is to be maintained. It might at first sight appear that the whole depth of the cup would be directly useful in forming the joint; or, in other words, that the hydraulic pressure acting on the internal surface of the rim of the cup would press the whole external surface of the rim of the cup against the pump barrel, and that hence the water-tightness of the packing would be enhanced by increasing the depth W/////A Fig. 33- of the cup rim. This is not, however, found to be the case in practice. The effective portion of the cup is merely a narrow ring of surface near the point A, Fig. 29, where the leather touches the piston, and the remaining portion of the cup leather is in a great measure superfluous. This fact is evidenced in several ways in a very convincing manner. For instance, the wear takes place almost entirely at A. Fig. 33 represents a section through a worn-out packing. The indentation B inside the packing is due to the external wear of the packing at A, as the leather is forced out by the internal pressure from the inside of the cup to supply the portions worn away by external friction. The localisation of the wear is so marked as to lead superficial observers to PACKINGS FOR SLIDING SURFACES. 7 1 suppose that the leather has been cut by the pressure of the edge of the piston. The effect is, however, entirely due to fair wear, and is not to be obviated by rounding the edge of the piston or other such expedients occasionally suggested. Another proof is furnished by the fact that the friction of the cup is independent of the depth of the rim, and is the same practically for a packing 2 inches deep as for one an inch or less in depth ; whereas, were the water-tightness of the cup due to the pressure on the whole internal surface of the rim, it would be reasonable to suppose that the friction would increase with the depth of the cup. The manufacture of a cup leather is a very simple opera- tion. A disc F of leather (see Fig. 31) of suitable diameter is soaked in warm water until quite pliable. It is then placed centrally on the hollow mould A, and the plunger B screwed down on it by means of the central screw c (the head D of which may be conveniently held in a vice) and nut E, until it is forced into the mould A. When the leather is dry the edge is trimmed off to an angle of 45, either by means of a sharp knife, or, preferably, in a wood chuck in the lathe. If the leather is required without a central hole, external clamps may be used in place of the central screw c to force the plunger B into the mould. If a number of leathers are to be manufactured, a small hydraulic press, of about 10 tons power, wall be found very convenient, as also a sheet-iron oven heated by steam for drying the packings. The latter, however, requires great care in use, as, if overheated in drying, the leathers rapidly fail in ordinary work. It is poor economy to use inferior material for hydraulic leathers. Sound oak-tanned leather should be selected, cut from the best part of the butt. If the packings are not subject to much wear, indiarubber cups may, however, be used with advantage in all cases where packings are liable to become dry through being used only occasionally. It has been previously remarked that the depth of a cup packing has but little influence on its water-tightness. We 72 HYDRAULIC POWER ENGINEERING. may further add that it is really prejudicial to the efficiency and durability of the packing to make the rim of the leather unduly deep, for the simple reason that the stress on the leather during its manufacture is greatly increased by in- creasing the depth of the cup. This stress is greatest also at the very part (A) of the leather which is subject to the greatest wear in actual work. If the cup be deep, and very great care be not taken in the manufacture, the leather is liable to tear at this point, or, if not actually torn, to suffer great deterioration, which, although it may be disguised and concealed by subsequent dexterous manipulation, never fails to show itself afterwards in an abnormally short life of the leather. There is no advantage whatever in making the cup more than i inch deep, and any greater depth than this is not merely useless, but, for the reason here pointed out, really undesirable as leading to injury to the packing at the very part at which the greatest soundness is required. The barrel in which the cup leather works should, if pos- sible, be lined with gun metal or brass. For medium and high pressures it should invariably be so lined. The attempt to use leather packings under high pressures for pistons working in cast-iron barrels, unlined, always results in great annoyance and frequent delays .from the rapid deterioration of the bore of the cylinder, and consequent constant failure of the packings, which are only durable when they have an absolutely smooth surface unaffected by corrosion to work against. In the case of thick cast-iron cylinders working at high pressures, owing, apparently, to the comparative porosity or looseness of texture of the interior surface of the casting forming the bore, which has already been commented on, the friction of the leathers appears at times to tear away considerable portions of the internal surface, leaving rough places, which destroy the packings after a few passages over them. Steel castings are not free from this defect, and suffer occasionally even more than cast iron. These remarks do not, however, apply so strongly to cast- PACKINGS FOR SLIDING SURFACES. 73 iron rams, the external surface of which is generally very close in texture and capable of receiving a high polish, and can a ] so be readily kept in good condition as regards polish and lubrication. Even in the case of rams, however, it has been found highly conducive to the durability of the leathers to case the lower part of the rams of hydraulic presses, for instance, with gun metal. The rams of hydraulic presses for baling Manchester goods, and for cotton pressing, are invariably so cased by first-class makers. The laws governing the friction of cup and similar leathers were investigated carefully by Mr Hick, of Bolton, and found to be in the main very simple. The author's own experience fully endorses Mr Hick's results, which may be stated in the following form : Let P be the total load on a ram or piston, and D its diameter in inches. The whole friction of the packing of the ram or piston is the leather packing being in the condition as regards lubri- cation usually met with in practice, and the ram and cylinder in first-class condition as regards polish and soundness of surface. For instance, let the ram of a press be 10 inches diameter and the load be 100 tons, corresponding to a hydraulic pressure of 1.27 tons per square inch, then the friction of the packing will be / 4 x 100 /= - - = .4 tons = 8 cwt. ; 100 x 10 or Z per cent, of the whole load. The friction in this case 10 is a very inconsiderable amount compared with the total load, but if the packing be small in diameter the percentage of the whole pressure absorbed by friction becomes very appreciable, and must be taken carefully into account when 74 HYDRAULIC POWER ENGINEERING. designing apparatus involving the use of pistons or plungers packed with leather for determining the intensity of hydraulic pressures. For instance, if the packing be J inch in diameter, the percentage of the whole load absorbed by the friction of the packing will be 44- J= 1 6 per cent., which is a very notable amount. Figs. 34 and 35. It will be observed that the above remarks as to the friction and wear and tear of leather packings apply equally to all leather packings of the cup type, and not merely to cups, but also to hat and U packings. The action of the hat packing (Figs. 34 and 35) and U PACKINGS FOR SLIDING SURFACES. 75 packing (Figs. 36 and 37) is, indeed, identical with that of the cup packing proper. The point of greatest wear and the method of calculating the friction are the same for all three kinds of packing. The tools used in and mode of manu- facture are, however, different, for neither the hat packing nor the U can be made in so simple a manner. F'igs. 38 Figs. 36 and 37. and 39 illustrate the formation of the hat packing from a circular disc of leather. The packing is finished by cutting out the central disc and chamfering the edge to an angle of 45. The pressure employed in forcing the leather into the die may be supplied by means of a central screw and nut, as previously described for the ordinary cup packing (p. 69). 76 HYDRAULIC POWER ENGINEERING. In this case, of course, a small hole must be first cut in the disc of leather for the central screw to pass through. This hole must in any case be small, otherwise it will be found impossible to make a satisfactory packing on account of the tearing and distorting of the leather. If screw clamps, or a small screw, or hydraulic press be employed, however, the central hole may be dispensed with. These remarks apply equally to the manufacture of U leathers, which indeed are frequently made by means of the press in which they are subsequently to be used. The dies used in the production of U leathers are illus- trated by Figs. 40 and 41. Fig. 38- Fig. 39- The pressing is effected in two stages ; first the leather is pressed into a cup shape (see Fig. 40) ; and at a second operation (Fig. 41) the cup is pressed into a hat shape, with a U-shaped rirn, part of the rim of the original cup going to form the internal rim of the U, as will be readily understood from the figures. The central disc is then cut out and the edges chamfered to an angle of 45, as in the case of the hat packing. The discs of leather used in the manufacture of leather packings are very readily and rapidly cut out of the hide by means of a knife-cutter fitted to the end of an ordinary hand- * drill, and adjustable to any radius by a set screw, the discs PACKINGS FOR SLIDING SURFACES. 77 cut out of the centre of large packings being, of course, used for smaller packings. The formula which we have already given for the friction of cup, U and hat packings, viz., where/ is the friction of the leather packing, P the whole load on the ram or piston, and D its diameter in inches, may be conveniently thrown into a form in which the friction is given as a function of the hydraulic pressure per square inch and diameter of the packing. For if/ be the pressure per square inch P =/D 2 x .7854 ; and hence f= .04 x .7854 x/D = .0314 x D/. y/\ V //A T777> 1 1 J V' ^%M$$jffi%$^fa Fig. 40. Fig. 41. In this form the formula is applicable to packings used for other purposes than maintaining rams or pistons tight, the pressure per square inch and diameter of the packing alone being required to be known. From the foregoing brief description of the method of work- ing leather hydraulic packings, the truth of our remarks as to the inadvisability of employing an unnecessarily deep packing will be sufficiently apparent, especially as regards U packings. Fig. 42 illustrates the proportions to be recom- mended for ordinary U packings, which will indeed be found ample for all purposes. The internal diameter of a U pack- ing should be about ^ inch less than that of the ram which 78 HYDRAULIC POWER ENGINEERING. passes through it, and the external diameter about j 1 ^ inch greater than the recess or cylinder in which it fits, the diameter being measured at A and B. This will ensure the tightness of the packing when first inserted. For large Fig. 42. packings a somewhat greater margin may be allowed. It is always best to fit the mouths of cylinders in which U leathers are used with glands (Fig. 43), the mouth of the ram being well rounded, so that the leather can be put in place without any injury to its shape or edges. The ends of rams should Fig- 43- Fig. 44. similarly be well rounded or tapered for a distance of say half an inch, with the same object. For many purposes it is, however, sufficient to simply turn a groove in the mouth of the cylinder to receive the packing, PACKINGS FOR SLIDING SURFACES. 79 as in Fig. 44. The leather, if of large diameter, is easily inserted in the groove by first doubling it into the shape illustrated by Fig. 45, but, if small, practice and care are necessary to avoid injury to the leather. A small leather is usually inserted by first suppling it by letting oil stand in the rim a short time, if the leather be at all harsh ; it is then pushed into the groove as far as it can be got to go, leaving as little remaining out of the groove as possible, and a blow or two from a piece of wood struck by a hammer will then usually suffice to put it in the shape illustrated by Fig. 46, and another blow at H will drive it neatly into the groove. Fig. 46. It is, however, better practice to fit the mouth of the cylinder with a gland. The studs securing the gland should not be subjected to a test stress exceeding 5 tons per square inch, if of wrought iron, and if this maximum be not ex- ceeded, a sufficient margin of strength will be provided to compensate for extra stresses due to unequal tightening of the nuts. The thickness of the flange of the gland, if of cast iron, may be ii- times the__jjanjefrpr of the studs, and ^~ STst Of THE UNIVERSITY 80 HYDRAULIC POWER ENGINEERING. the width of the flange three times the diameter of a stud. The projecting portions of the gland should be ii times the stud in length. If/ be the hydraulic test pressure per square inch, d the diameter of the ram, and c the width of the packing, the whole stress on the studs due to the hydraulic pressure is (d+c)cir p = 3.1416 (d+c)pc. Hence if n be the number of studs, and d l the diameter of a stud at the bottom of a thread, the stress on the studs per square inch is (d + c)c*p + nd**=***( d + c ) 4 nd^f which, as before stated, should not exceed 5 tons, or about 1 1,200 Ibs. We have recommended -| inch as the most suitable dimen- sions for c, but if circumstances render it advisable to reduce the space occupied by the packing to minimum limits, c may be diminished to T 7 g- inch without very greatly subtracting from the efficiency of the packing. There is a difference of practice among manufacturers of hydraulic packing leathers, some preferring to use the grain and some the skin side of the hide for the wearing surface. The latter plan makes the neatest leather in appearance, and is generally to be recommended. Hemp Packing. The first cost of leather hydraulic packings is comparatively high, and if the surfaces against which they work are not carefully looked after, and maintained in a state of perfect polish and well lubricated, the packings will deteriorate rapidly and become no inconsiderable portion of the expense of maintenance of a hydraulic plant. For these reasons hemp packings, which are water-tightened by strong mechanical compression by means of a stuffing box and gland, are used by many engineers wherever possible ; since PACKINGS FOR SLIDING SURFACES. 8 1 the first cost of the hemp packing is comparatively incon- siderable, while at the same time the packing can be renewed more rapidly and with less loss of time. If the rod or plunger which is to be packed is heated, as is necessarily the case with some types of steam pumps, leather packings are altogether inadmissible, and hemp, asbestos, or some similar packing must be used. On the other hand, the friction of the mechanically com- pressed hemp packing is far greater than that of the self- acting leather packing ; also, if the hydraulic pressure for which the packing is used be high (and hemp packing, contrary to the opinion of many, may be employed success- fully for very high pressures, such as 3 tons or more per square inch), there is considerable risk of scoring the surfaces of the ram and plungers in actual work, owing to the neces- sarily intense pressure with which the packing must be forced against the sliding surface in order to secure water-tightness. A further objection to hemp packing is that the packing must be compressed with sufficient force to ensure its being tight under the highest pressure at which the machine in which it is used is intended to work ; hence, although the machine may be frequently working under a comparatively low pressure, the friction of the packing is always that due to the higher pressure, and may amount to a very large percentage of the whole work done by the machine, whereas, if leather packings be used, since the pressure on the packing varies directly with the work which the machine is performing, the percentage of power absorbed by the friction of the packings is, within certain limits, prac- tically constant. It must be left, then, to the judgment of the engineer to decide which description of packing shall be employed in any given case, each type having its own special advantages and defects, which must be duly weighed and taken into consideration before arriving at a decision. The friction of hemp packings cannot be so definitely determined by ex- F 82 HYDRAULIC POWER ENGINEERING. periment for any given conditions of use as that of leather hydraulic packings. We have not merely to consider the intensity of the hydraulic pressure employed, as in the case of leathers, but the depth of the stuffing boxes and diameter of the packing surface, as also the degree of pressure applied by means of the stuffing box gland. Under the same degree of compression there is no doubt that a deep stuffing box will produce more frictional resistance than a short one ; but, on the other hand, the deep stuffing box will not require so in- tense a compression as the short one, and hence in actual practice the friction of the short stuffing box may exceed that of the long one, if the packing is to be water-tight under a given maximum pressure. It is, however, very desirable in practice to have a simple formula by which to determine the probable maximum friction of a hemp packing under given conditions. If the packing be screwed up judiciously, and the stuffing box of fair proportions, the formula may take the form of cpd=f, where c is a constant, to be determined by experiment within assigned limits as to pressure and diameter, / the hydraulic pressure (maximum) per square inch, d the diameter of the ram or rod in inches, and /the total amount of the friction. For many purposes it is suffi- cient to take /as equal to one-tenth the pressure per square inch, multiplied by the diameter of the ram, or/= , and 10 the friction of a hemp packing judiciously used will rarely exceed this amount within very wide limits of pressure and diameter. A very simple method of ascertaining the approximate friction of a ram packing is available when the ram can be loaded and fixed so as to rise and fall vertically. Let the ram be loaded, perfectly centrally, with any weight, the amount of which need not be exactly ascertained, and let the pressure per square inch required to raise the ram at the lowest speed be ascertained by means of an accurate pressure gauge communicating directly with the cylinder, PACKINGS FOR SLIDING SURFACES. 83 and let the pressure be P 1 . Next let the pressure in the cylinder be similarly ascertained when the ram is descend- ing as slowly as possible, and let the pressure be P 2 . It is very important that the motion of the ram should be exceed- ingly slow during the experiment. Then the friction of the P - P packing will be approximately - x area of ram in square inches. It is most necessary in carrying out such an experiment as this, however, to test the accuracy of the pressure gauge employed, since the ordinary commercial pressure gauge is frequently grossly inaccurate, and in the case of high hydraulic pressures as a general rule absolutely unreliable. The following table gives suitable dimensions of the pack- ing space for stuffing boxes of various diameters : Diameter of Ram. Diameter of Stuffing Box Depth of Stuffing Box. Diameter of Ram. Diameter of Stuffing T> Depth of Stuffing Box. Inside. IJOX. Inches. Inches. Inches. Inches. Inches. Inches. I It 2 12 Hi 6 2 2 2f 3 14 i6| 7 3 4* 16 18^ 74 4 5i 4 18 2O| 71 5 6^ 4^ 20 22* 8 6 71 41 22 25 84 8 8| 9! 5| 54 24 26 3 9 9 ii 5S 28 34 9i 10 I2i 6 30 33i 10" The dimensions of the gland studs for stuffing boxes should be proportioned in a similar manner to those for the glands for U leathers, but with a larger margin of strength. 84 HYDRAULIC POWER ENGINEERING. Let, as before, n be the number of studs or bolts /*/! the diameter of a stud at the bottom of the I thread. . ID the diameter of the ram or rod. j Dj the internal diameter of the stuffing box. I P the maximum pressure in pounds per square inch. Then d^~ should not be less than (D 1 -D)(D 1 + D)P 5000 x n The thickness of the flange of the gland should not be less than if times the external diameter of the stud, and its width may be three times the diameter of a stud for cast iron. P in the above formula is to be taken as the maximum working pressure, or one-half the test pressure, the larger of the two values being selected ; that is, if the maximum working pressure be greater than half the test pressure, P must be taken equal to the working pressure ; but if half the test pressure be greater than the maximum working pressure, then P should be taken equal to half the test pressure. Table IV. gives the efficiencies of rams or rods, working with leather or hemp packing. It has been calculated from the preceding rules, and will be found to agree with practice, providing the stuffing box is of fair proportions, and the ram or rod polished and lubricated. Let P = gross power of ram = area of ram multiplied by pressure per square inch. ,, Pj = nett power of ram. ,, c = coefficient, taken from table. Then P^P. PACKINGS FOR SLIDING SURFACES. TABLE IV. COEFFICIENTS OF RAM EFFICIENCIES FOR HEMP OR LEATHER PACKING. Diameter of Ram. Stuffing Box. Leather Packing. Diameter of Ram. Stuffing Box. Leather Packing. Inches. Inches. TV 36 3i .96 .98 A 57 31 .06 .98 i ... .68 4 . 9 6 99 -.', Tfi .78 4i 97 99 * .49 .84 5 97 99 A 59 .87 5 97 99 1 .66 .89 97 99 / .70 .90 61 .98 99 i 74 .92 7 .98 99 A 77 .92 74 .98 99 f 79 93 8 .98 99 H .81 94 84 .98 99 i 83 94 9 .98 99 7 8 .85 95 94 .98 99 I .87 .96 10 .98 99 I* .88 .96 ii .98 99 ii .89 .96 12 .98 99 i| .90 97 13 99 99 if .91 97 H 99 99 i* .92 97 15 99 99 'I .92 97 16 99 99 i! 93 97 18 99 99 2 -93 .98 20 .99 99 2i 94 .98 22 99 99 2* 94 .98 24 99 99 22 95 .98 26 99 99 3 -95 .98 28 99 99 3* .96 .98 30 99 99 CHAPTER VII. PIPE JOINTS. IN our last chapter we described the usual methods of making the joints between sliding surfaces water-tight by means of animal and vegetable packings, in a self-acting manner or by forcible mechanical compression of the packing material by means of glands or bolts, or their equivalents. In the present article we propose to treat similarly of the various methods of making the joints be- tween surfaces, fixed with reference to each other, water- tight. The joints between such surfaces are made either by placing between them suitable sheets or rings of canvas, lead, copper, leather, indiarubber, guttapercha, paper, and various other material, and forcing them tightly together by means of bolts and nuts, or their mechanical equivalents ; or by using U or similar self-acting packings. In designing such a joint we have principally to consider the stress which must be brought upon the metal of the bolts and nuts in order to ensure water-tightness under a given pressure, and the dimensions which it is advisable to give the flanges, in practice, in order that they may be of adequate strength to resist the stress thus brought upon them. The stress upon the bolts, considered as a simple tensile stress, consists of two parts in general one due solely to the hydraulic pres- sure on the surface exposed to it, which may be exactly calculated when the extent of that surface is known, and the pressure per unit of area to which it is subject ; and another part due to the elastic reaction of the surfaces themselves and that of the joint material between them. To make this clear, we will consider a joint such as that nrE JOINTS. 87 illustrated by Fig. 47, in which B may be a valve chest, for instance, and A its cover; the joint being made by truly facing the surfaces, painting them, inserting a sheet of brown paper say between them, and then drawing them forcibly together by screwing up the nuts and bolts which pass through the flanges. If the nuts be screwed up when pres- sure is not admitted to the valve chest B, a complicated stress is brought upon the metal of the bolts mainly a longitudinal tension, but complicated by torsional stress due to the inclination of the helix of the screw-thread and the friction between the thread and nut brought into play by the twisting action of the spanner, and complicated in addition Fig. 4; by possible bending stresses due to inequality or unequal yielding of the joint surfaces and flanges. For true surfaces and faced nuts, we may, however, treat the stress in practice as a simple tension. Let L be the length of the spanner used in inches, and F the force in pounds applied at its end by the workman in screwing up ; then for ordinary bolts, having Whitworth threads, the total stress in tension on the metal of the bolt may be fairly taken at an average value of 6FL. f = in pounds, where T is the whole stress on the bolt in pounds, con- sidered as tensile, and d is the diameter of the bolt over the 88 HYDRAULIC POWER ENGINEERING. thread in inches, the stress on the bolt per square inch at the bottom of the thread may, of course, be found by dividing T by the area of the section at the bottom of the thread. If now water be admitted to the valve box p>, at a pres- sure of / pounds per square inch, and S be the surface of the cover A exposed to the pressure in square inches, the whole upward pressure on the cover A will be /S in pounds, and this pressure may be transmitted to the bolts practically undiminished or increased, in addition to the stress T due to the screwing up, making the whole load on the bolts where n is the number of bolts. We say may be so transmitted advisedly, as the determina- tion of the exact amount which will be added to the initial stress on the bolts in every particular case is highly complex, and indeed hopeless from an engineer's point of view, in very many cases depending, as it does, on the extensibility or compressibility of the various parts forming the joint. In practice we need not, however, enter into such an in- vestigation ; it is sufficient for our purpose to know that the whole load on the bolts of the joint is not likely to exceed the amount stated, viz., 6FL so that if the effective area of the bolt section be pro- portioned to sustain this load safely, the error, if any, will be in general on the side of safety. It is to be remarked that of the two parts of the expression for the whole load on the bolts, the one part, />S, is usually determinable with fair accuracy, whereas the other part, 6FLa , can only be fixed by estimation. In fixing the value to be assigned in any particular case to this latter PIPE JOINTS. 8 9 part, we may take a step towards a simplification of the expression by assuming that L bears a definite relation to d. For instance, let L = ;;/ y.d ; then the load on the bolts will be 6mn +/S = say W. Table V has been calculated from this formula, assuming ;//= 1 6, and F = 5 S Net Test s,+s of Bolt. Screwing up = 6wF. Ud= 2 =i^, where r is the radius in inches, and / the pressure per square inch in tons, so that A _ 2 I2.2X.3 ~ f- x / 2^7 = i. 7". Flat cylinder ends are only suitable for very small sizes and low pressures, owing to their great thickness for mode- rate strength. For large cylinder covers the.dished form is generally employed and shown in Fig. 16 (ante] and Fig. 50. When there is a joint, as in Fig. 50, the rise V should be about one quarter the diameter, and the thickness of the cover the same as the sides of a cylinder of diameter /. The cover and cylinder will then have about equal strength. The question of bolts has been already dealt with. Fig. 51 illustrates the old method of joint for a long hydraulic main, while the more modern method adopted by the London Hydraulic Power Company is shown in side elevation and section in Fig. 52. The joints are of the spigot and faucet type, turned up with a V groove, in which is inserted an indiarubber or guttapercha ring. The pipes are made in about 9-foot lengths, and are held together by the bolts passing through the lugs at the end of each length. In the old form of pipes the face of the lugs was nearly flush with the end of the pipe ; but in this new form shown in Fig. 52 the lugs are set back some distance from the end, G 98 HYDRAULIC POWER ENGINEERING. an improvement which has been found to increase the strength some 35 per cent., very few failures of lugs having occurred since this form was introduced by the Company, Fig. 50- whereas with the old type of lugs failures were not un- common. Fig. 53 is a full size section of the rubber ring when compressed in the V groove. Fig. 54 illustrates the ordinary socket and spigot joint PIPE JOINTS. 99 used in long mains, in which the pressure does not exceed 250 Ibs. per square inch. After placing the spigot end of one length in the socket end of another, and ramming into Fig. 5 1 - the bottom of the socket some greased hemp, the joint is made by pouring in molten lead. The lead by running into the groove A round the inside of the socket prevents the pressure from forcing the plug of lead out. If the main ^ i --- \R 1 3- er KS/nCHfS. | 1 _ a s to AT Fig. 52- is intended for a permanency, the socket may be filled with a rust joint cement in place of lead. A good joint compo- sition is as follows: 2 parts by weight of sal-ammoniac, 100 HYDRAULIC POWER ENGINEERING. i part flour of sulphur, 200 parts iron borings ; the whole made to a paste with water. This mixture makes a lasting cement, although a slowly setting one, and is one not to be used when the pipe is required for immediate service. Fi g- 53- The drawback to a rust-joint is that the pipes must be broken if any alteration to the main is required, as the cement sets harder than cast iron, if properly made, whereas with a joint made with lead the lead can be cut out if the joint is to be broken. In socket and spigot jointed mains it is a good practice to put flange joints every 100 or 150 feet run for the convenience of alterations or repairs. When a pipe main is laid on the surface of the ground, exposed to the varying temperature between day and night, expansion joints (Fig. 55) are sometimes put in the main PIPE JOINTS. 101 at intervals of 400 to 500 feet to obviate the tendency to crack, and to prevent the creeping of the joints, which commonly causes leaks. The expansion joint shown in Fig. 55 is formed by turn- ing the spigot end of one length of pipe to work through a bored gland and stuffing box cast on the socket end of another length of pipe. The gland and stuffing box are bushed with gun metal, and the gland packed with hemp in the usual way. In an exposed main it is necessary to anchor the stuffing box length of pipe firmly to a concrete or stone block to prevent its tendency to creep. Especially is this necessary if the main is on an incline instead of lying horizontally, for gravity will then assist the creep of the pipe down the incline. Fig- 55- An exposed main of cast-iron piping, some 500 feet long, will vary on the average i inch in its length between mid- day and midnight in the summer season ; but this amount of expansion will be reduced to about .3 inch if a stream of cold water be kept rapidly and continuously running through the pipe. It is not always possible or convenient to arrange cast- iron mains or conduits for conveying the hydraulic pressure, in which case it is desirable to be able to attach, at any re- quired position upon the pipe employed, a means of connect- ing one portion with another, or of attaching a branch to the main supply. 102 HYDRAULIC POWER ENGINEERING. Pipes of wrought iron, steel, or copper, under 3 inches diameter, may be very readily jointed together for low pres- sure by means of a right and left hand screw coupling socket nut, which draws the ends together into metallic contact ; Fig. 56. the end of one pipe being turned truly flat, and the other to a truly sharp edge, as shown in Fig. 56. The objection to this mode of coupling arises from the difficulty experienced Fig. 57- in releasing the pipes, it being impossible to undo the joints unless the pipes have room to separate when the nut is un- screwed, which, in many cases, would be quite impracticable. A similar mode of jointing is shown in Fig. 57, in which a PIPE JOINTS. 103 rubber ring is inserted to make the joint, but of course the same objection applies in this case as to the former joint. The more common, although more costly, method of jointing pipes is illustrated at Fig. 58. The end of one pipe is screwed to receive a collar A, and before this collar is placed upon the screwed portion a nut B is passed over the pipe, so that the nut is then made, as it were, a part of the pipe. The end of the junction piece, or T-piece, is also similarly screwed, and a leather washer is inserted between the ends, as shown. The connection of copper pipes is usually effected by the method illustrated at Fig. 59, the socket being brazed on to one and the flange brazed on to the other end, having first been screwed on their respective pipes. 104 HYDRAULIC POWER ENGINEERING. Fig. 60. Fig. 61, PIPE JOINTS. 105 With the application of hydraulic power to cranes, rivet- ing machinery, etc., swivelling or turning joints for the walking pipes are a necessity. Fig. 60 illustrates a gun- Fig. 62. metal right-angle swivelling connection for a pressure of not more than 700 or 800 Ibs. per square inch. It consists of a flanged pipe A turning easily in the elbow piece B, having io6 HYDRAULIC POWER ENGINEERING. the stuffing box c enlarged so that the ring D may seat on the shoulder and relieve the flange of the pipe A from any pressure consequent upon screwing down the gland E. Fig. 6 1 shows the same kind of swivelling connection, but having a hat leather packing in place of a stuffing box. Both these D types answer well, but have the one drawback of the pres- sure acting on the sectional area of the pipe thickness and forcing the flange of the pipe A against the ring D to an extent which prevents this form of connection being used for higher pressures than above stated. To obviate this the joint shown in Fig. 62 is adapted, in which the swivelling PIPE JOINTS 107 piece A is packed by two U leathers B, which are kept apart by the brass ring c, this ring being drilled with holes for the passage of the water. The leathers are secured in their position on the pin D by means of the washer E and nut and cotter F. If due care is taken in its manufacture, this joint is thoroughly reliable, with pressures up to 1,600 Ibs. per square inch, and lasts a long time before requiring renewal of the packing. Fig. 63 illustrates a similar connection, but with plain leather washers for packing in place of the U Fig. 64. leathers, as shown in Fig. 62. The swivelling piece A has a shallow stuffing box B at each end, for which the rings c c act as the glands, these glands being fitted with pegs so as to turn with the piece A, and they can be tightened up by means of the locking nut D. Fig. 64 shows a swivelling joint suitable for a pressure of 3 to 4 tons per square inch, in which hat leather packings are employed. The hollow pin or pipe c has an enlarged end at B round which the joint A revolves, and is secured from sliding endways by the set collar E. Sometimes the 108 HYDRAULIC POWER ENGINEERING. hollow pin or pipe c has the swell B made the whole width of the turning joint A, in which case two set collars are required, one at each side of the turning joint, and close to the gland nuts, to retain the joint A in position. This last arrangement has the advantage that it permits of the in- troduction of fresh leathers without disconnecting the pipe c. PART IV. VALVES. CHAPTER VIII. CONTROLLING VALVES. OF all the auxiliary mechanism employed in hydraulic power works the valves are the most important, for on their efficient working depends the success of the under- taking. The design of valves for hydraulic machinery varies accord- ing to the purposes for which that machinery is intended, and the constant applications for patents in connection with hydraulic valves must be taken as evidence of the import- ance of the subject, and at the same time as a proof of the necessity for the special attention which is necessary in designing any hydraulic valve. In the present chapter it is intended to point out some of the leading features that go to make a successful working valve, and then to describe in detail some of the more common types of valves. Fig. 65 illustrates an ordinary form of stop valve for medium pressures consisting of a cast-iron body A, having lugs for connecting to the pressure pipes forming the hydraulic main, and provided with a cap secured to the valve body by the studs B. A hard gun-metal valve seat is screwed into the body at c, making a tight joint by means of the rubber ring. The cap has a tapped gun-metal bush D, in which works the screwed stalk of the gun-metal valve spindle E ; the bottom of the stuffing box has a gun-metal bush F, and a gland ring G presses upon the packing when the cap is screwed down. If H is the diameter of the bore in the bush, the valve seat of which is angled off at 45, and the end of the valve spindle is level with the bottom of the mitre seat 112 HYDRAULIC POWER ENGINEERING. when the valve is shut, then the required lift of the valve spindle E off its seat so as to have an annular space between it and its seat equal in area to the water passage H is .305!! ; but in order to lessen the loss of head consequent upon the Fig. 65. flow of water through the valve the lift of the spindle E is made from -375H in large valves to .5!! in small ones. For a similar reason the sectional area of the annular space j round the spindle should not be less in width than 375H. In general practice it is better to shut the valve against CONTROLLING VALVES. 113 the flow of water than with it, for the reason that the water pressure on the spindle causes all backlash in the screw-threads and other parts to be taken up before the closing of the valve. To prevent leakage, the pressure of the spindle E upon its mitre seat c per square inch of seat surface requires to be at least equal to the water pressure per square inch. Let H and HJ equal respectively the inner and outer diameter of the mitre turned on the valve seat, also let/ be the water pressure per square inch and P the least total pressure on the valve spindle E to ensure the water not leaking through, then We may now determine the size of a hand-wheel for, say, a ij-inch stop valve for 750 Ibs. pressure per square inch. Let x equal the diameter of hand-wheel, and assume a man can exert a maximum turning effort of 120 Ibs. on the rim of the hand-wheel. For a valve of this size the spindle E would be about i| inches diameter, and the pitch of the i ^-inch screw cut upon the stalk about 6 threads per inch. In this example there are four resistances to be overcome by the hand-wheel, viz., P, the pressure ; the friction of the valve when turning on its seat at the instant of closing, which, taking .3 as the coefficient of friction, equals .3^ (Hj 2 - H 2 )-; 4 the friction of the spindle in its stuffing box, which may be obtained from Table IV., thus (i --93)P ; also the friction of the screw due to the pressure P, the coefficient of friction being in this case .15. For one revolution of the hand-wheel the work done amounts to 120 x x x TT, which must balance the resistances : (i.) Pxl" + = I2O X X X 7T, (4.) .15? x i" x TT H HYDRAULIC POWER ENGINEERING. Solving this equation for x we get the above example, 8.5 inches as the diameter of the hand-wheel. In large stop valves, from about 4 inches and upwards, it is found necessary to attach a balancing arrangement, otherwise one man would not be able to open or close them. Fig. 66 illustrates a similar stop valve to that shown by Fig. 65, but having its valve spindle packed by a leather lace Fig. 66. instead of the ordinary stuffing box. This method of pack- ing answers very well for valve spindles not more than i J inches diameter, but for diameters above ij inches the stuffing box form of packing should be adopted. Where a number of hydraulic tools are at work it is advisable to put in the main a safety valve, for the simul- taneous stopping of several tools will so suddenly check the falling accumulator as to augment the normal pressure to a dangerous extent unless it can find relief. The safety or CONTROLLING VALVES. 5 shock valve shown in Fig. 67 is designed for this purpose, and consists of an ordinary cast-iron T-piece, having flanges for bolting to the pipes forming the hydraulic main, the stalk of the tee piece being provided with a gun-metal mitre valve and seat, while the valve is loaded by a combined adjustable spring and dead-weight lever. The minimum pressure is put on by the spring by adjusting the height of the cross- head and locking the nuts, and the additional pressure above Fig. 67. Fig. 68. that of the accumulator is obtained by adjusting the position of the weight upon the lever. Fig. 68 illustrates a closed-up spring-loaded safety valve, of which the body is made entirely of gun metal with an overflow pipe at A. The point of suspension of the spring- loaded plate is above the plane upon which the spring bears to ensure stable equilibrium. This form of relief valve pre- vents any tampering with it after the spring is set to allow the valve to lift at a given pressure. i6 HYDRAULIC POWER ENGINEERING. Although safety valves relieve the pipe of stress from ex- cess of pressure, they have the disadvantage of allowing the water that flows through the valve to run to waste. To obviate this the arrangement as illustrated by Fig. 69 is em- ployed, which is called a shock or relief valve, and consists of a closed- up spring-loaded small ram working through a stuffing box and gland in a cylinder having branches for con- necting to the pipes of the hydraulic main. The ram is loaded by the spring to the working pressure by the method shown in Fig. 68, and when the pressure through any cause rises above the normal the ram is raised, and thus the pipe is relieved of any excessive stress that would occur if there were no relief. The spring can be either cylindrical or of volute form, but in any case it must be sufficiently long to admit of a large deflection without much increase of pressure. The apparatus is practi- cally a small accumulator. The London Hydraulic Power ?^_ Company place a shock valve on each side of every stop valve in their 6-inch pressure main, and in most hydraulic plants worked by an accumulator it is advisable to put a shock valve in the delivery main close to the accumulator. In most forms of hydraulic machinery worked by pressure energy that part of the mechanism which is acted upon directly by the water pressure consists in some form or other of a ram working in a cylinder rendered water-tight by means Fig. 69. CONTROLLING VALVES. 117 of a hemp or leather packing, such as the ram of a press or lift, and the function of the valve is to admit the water from the pressure pipe to the cylinder, and then to close the admission when the ram has run out sufficiently far, and finally to open the cylinder to exhaust so that the water within the cylinder may run to waste while the ram is returning in - 'o c) ' o o s p n 1 f* -tl-P- t KJLT - o o o J L Fig. 70. most cases without hydraulic aid. The type of valve in common use for low-pressure lifts is shown in Fig. 70, and is termed a rack slide valve. A is the gun-metal valve sliding on a gun-metal face pinned to the cast-iron valve body. The valve is worked by a rack on its upper side engaging a pinion B, which is fast on the axle of the rope wheel F. An u8 HYDRAULIC POWER ENGINEERING. CONTROLLING VALVES. I 19 endless rope engages this wheel, one end of which passes up through the cage or platform of the lift, c is the pressure inlet, E the branch for connection to the lift cylinder, D the outlet or exhaust, G the pressure port, always open, H the port leading to the cylinder, and K the exhaust port. The side of the port H opening to pressure is often cut in the shape of a large V, so that the closing of this port to pressure may be effected more gradually and thereby reduce the chance of any shock. The valve is shown in the posi- tion when the cylinder is fully open to exhaust, and on pulling the rope so as to move the valve A to the right, the exhaust is closed, in which position the valve face should lap at least J inch over each side of the port H to ensure no leak- ing. Upon moving the valve further to the right it uncovers the port H to pressure. This form of valve is particularly convenient for any kind of hydraulic lift or crane, as the rope working the valve can be led away in any direction. Sometimes small shock valves are inserted in the slide valve body, but for low pressures the general practice is to put an air vessel between the valve and the cylinder to reduce the effect of shock. The rack slide valve is seldom used for larger inlets than 3^ to 4 inches, as the friction of the valve on its face is then more than can conveniently be overcome by one man, and the type of valve shown by Fig. 71 is then generally adopted for low-pressure lifts. It consists of a leather packed gun-metal piston valve D 1? and rod D actuated by a rack and pinion E and working in a gun-metal lined cast-iron valve body, having the branches A to pressure, B to cylinder of the lift, and c to exhaust. The gun-metal liner has narrow vertical slots or holes cut round it, opposite the branch B, and these slots are covered by the piston valve D lt when in the middle of its stroke. F is the rope wheel round which a cord is wound and led away to the lift. As the pressure is acting on equal piston valve areas the valve is balanced, permitting the wheel F to be easily revolved. When the piston valve is lowered so as to uncover the top I2O HYDRAULIC POWER ENGINEERING. end of the vertical slots, the pressure passes from A along the branch B to the cylinder, and when the piston valve is raised so as to uncover the bottom end of the slots, the water in the cylinder can pass by the branch B into c, and thus to exhaust. Slide valves cannot be successfully used for pressures exceeding 1,600 or 1,700 Ibs. per square inch, and although many attempts have been made to automatically balance them, failure has invariably been the result, owing to the fact advanced at the beginning of this chapter, viz., that a valve to be tight must be pressed upon its seat with at least an equal pressure per square inch to that of the water. Fig. 72 illustrates a slide valve similar in working to the one shown in Fig. 70, but modified in design, for pressures up to i, 600 Ibs. per square inch. A is the connecting branch to the pressure main or supply, B is the branch to the exhaust, and c is the branch to the cylinder. This valve in the smaller sizes is usually made of gun metal throughout, having a loose face K pinned on to the body. The valve rod L is enlarged in the middle of its length, and has a hole cut in it to receive the stalk of the valve D. The rod works through packed glands at each end, and is so arranged that it can be withdrawn through the stuffing box. The ports F and G, which lead into the branches B and c, are opened and closed by the slide valve D, and the enlarged part of the rod L prevents the valve moving too far either way. Should the lift or crane which is worked by this valve be suddenly checked, when lowering with a heavy load, by moving the valve to close the port G, the pressure in the cylinder would be augmented above the working pressure. This excess pressure then finds relief through the bye pas- sage H and small flap valve E. This small valve E then becomes a shock valve, and is usually made in the form of a weighted leather washer, pinned or screwed to the face of the valve body, as shown in the plan. The advantage CONTROLLING VALVES. 121 in making the ports G circular is the possibility of a more gradual opening and closing of the ports than is obtained with rectangular openings. There are various ways of operating this valve. For in- stance, the valve rod L can be connected to a rack and . . ? . . 1 ! * Fig. 72. worked by a pinion and rope wheel, as in Fig. 70, or it can be readily worked by a combination of levers. When the pressure exceeds 1,600 Ibs. per square inch the valve should be of the design illustrated by Fig. 73, first employed by Lord Armstrong's firm for crane purposes. 122 HYDRAULIC POWER ENGINEERING, The valve can be worked vertically or horizontally as may be desired. A is the pressure inlet, B exhaust outlet, c the passage to the press or lift cylinder ; D and E are the valve Fig. 73- spindles working through stuffing boxes, and closing the ports to A and B respectively. These spindles are kept down on their seats by means of the springs G and H bear- CONTROLLING VALVES. 123 ing against the crossplate j, this latter being secured to the valve body by two bolts. The proportions or sizes of the springs may be determined by the method stated at the beginning of this chapter. The valve spindles are lifted by means of a T-shaped lever F. On pulling the lever to the left or right the spindle valve D or E is raised, and on releas- ing the lever the valves automatically close the ports. The larger sizes of this design of valve are fitted with a small shock relief, as already described. For heavy pressures up to 3 and 4 tons per square inch the simplest and most convenient type of valve is illustrated by Fig. 74. It is usually made entirely of gun metal, the 124 HYDRAULIC POWER ENGINEERING. Fig. 77- CONTROLLING VALVES. 125 valve spindles A and B being packed with leather laces and fitted with handles. In using this valve the spindle A is opened first, admitting pressure to the cylinder of the press ; it is then shut, and the valve spindle B opened, allowing the water from the cylinder to exhaust, care being taken not to have both valves open at once, or the pressure water will run to waste. To obviate the possibility of both valves being opened at one time the author has designed valves with spindles placed side by side, and actuated by means of gearing working right and left hand screwed valve stems. A good example of a partially balanced spindle valve is shown in Figs. 75 and 76. Fig. 75 is a sectional elevation, and Fig. 76 the plan of Meacock's valve for admitting the pressure to the cylinders of the two power jigger or multiple chain lift shown in section by Fig. 77, in which c is the inlet to the cylinder containing the small ram, and c 1 the inlet to the cylinder containing the larger ram. The valve arrangement consists of four plug valves D D 1 , E E 1 , which are held upon their respective seats by the water pressure acting upon the increased area of their spindles F F 1 over the areas of the valve ports G G 1 . The chambers H H 1 above the spindles F F 1 are charged with water. This water has to be displaced during the rising of the plug valves, and they can only automatically return upon their seats as the chambers H H 1 become charged with water through the clearance effected by the diameter of the valve stalks i i 1 being less than the diameter of the passages in which they work, thereby ensuring steady action. The springs j j 1 are for the purpose of keeping the plug valves D D 1 , E E 1 upon their seats when water pressure is shut off from the supply main. The pressure inlet is marked K, and is common to both of the valve plugs D D 1 . The exhaust outlet is marked L, and serves for both the valve plugs E E 1 . The pipe M communicates with the internal ram B through the inlet c, and the pipe N is connected at c 1 to the cylinder A 1 containing the ram A. The valve plugs D D 1 , E E 1 are 126 HYDRAULIC POWER ENGINEERING. Figs. 78 and 79. actuated by the two double cams o o 1 fixed on the spindle p. By partially rotating the spindle P in one direction by means of a wheel or a lever fixed to it, the valve plug D is raised, thereby admitting pressure to the ram B, and by further rotating the spindle p the valve plug D is liberated by means of the slipping link Q, when it automatically seats itself, thereby closing com- munication to the ram B. During this time the cam raises the valve plug D 1 , so that the annular area of the ram A is admitted to pressure. For raising a maximum load a third movement of the cam again raises the valve plug D, at the same time retaining the valve plug D 1 open, both rams now being subjected to pres- sure. If the spindle P is turned in the opposite direction, thus causing the cams to operate upon the exhaust valve plugs E E 1 , either the small cylinder B or large cylinder A 1 may be opened to exhaust, or by a further movement both may be opened. By this means a great economy of pressure water is effected, CONTROLLING VALVES. 12? An arrangement of four slide valves may be used in place of the four spindle valves just described, as shown in sec- tional elevation and plan in Figs. 78 and 79. The slides are made to automatically cover the ports leading to the cylin- ders A 1 B by the pressure acting upon the valve spindles D o 1 , E E 1 , as shown at R R 1 . These slides are caused to open the ports to admit pressure to the cylinders A 1 B, or to put them to exhaust by the action of the pair of double cams o o 1 fixed upon the spindle P, and operating in a similar manner to that described for the opening of the plug valves. The inlet K is connected to the pressure main, and the outlet L to the exhaust, while the pipe M communicates with the inlet c, and the pipe N with the inlet c 1 . Brindley's patent water pressure balanced pilot valve controlling a larger main valve is employed with advantage when a small movement is desirable for the operating lever as in connection with riveting plants and hydraulic presses. PART V. -LIFTING MACHINERY CHAPTER IX. PLATFORM LIFTS. ONE of the most popular applications of hydraulic power is connected with lifting machinery, when passengers or goods are raised from floor to floor of lofty warehouses, or for general manufacturing premises. The question of correct working is greatly misunderstood, and what is far more serious the safety of such lifts is only too often a matter quite ignored by those responsible for the working of the machines. It is said that any person can construct a lift, for the pressure is on the water, and the only thing remaining for the constructor is to make a simple machine to transform this pressure into mechanical power. Then again, too, safety appliances are mentioned as being specially provided to meet any emergency which is likely to arise, so that the possibility of danger or accidental occurrence is a matter to be treated with equanimity by those about to trust their lives in such machines ; whereas the fact is only too painfully advertised that but few persons can properly construct and erect a lift which is at once economical, safe, and simple in principle. There is probably no piece of machinery subject to more unfair usage and more rough and careless handling than the hydraulic lift, for it is to be everybody's assistant, and every one handles it in a manner that he or she considers to be the best way. We' have known valves to be pulled violently backwards and forwards by warehouse and factory lads and girls, causing shocks and strains to be given to all parts of the machinery, which have produced permanent injury and sometimes disaster ; while in many cases fatal accidents, attributed to the lift, and reported as " another 132 HYDRAULIC POWER ENGINEERING. lift accident " in the daily journals, may be clearly traced to reckless and contributory negligence on the part of those injured. Similarly, the so-called safety appliances seldom prove of service in the cheap and common lift, for being always in a stationary or fixed position during the normal working, they get quite stiff, rusty, and clogged up with dirt and grease, and refuse to act when suddenly they are liberated after long standing unused. To be of any practical or real service as safeguards, the appliances which are supposed to arrest the motion of the cage or lift platform when an accident occurs, such as the severing of a cable or chain, or the disconnection of a ram, should always be in actual use or work. They should form the absolute and definite base upon which the motion of the car or platform depends, so that in the event of any failure occurring the gear at once comes into play, and does its part promptly and well. When this condition of con- struction is more fully understood, we shall hear less of such accidents, which have made lift-users tremble in the past, and which have caused the demands to be made for com- pulsory registration of all passenger hoists and lifts. The author considers that every lift should be under the super- vision of the Board of Trade, and licensed before being allowed to carry passengers. There is in many minds a strong prejudice against being pulled up by any mechanical appliance used in connection with hoists and lifts, while the same feeling does not appear to be induced when the persons are pushed up. Thus it is that nervous persons entering a lift, which is suspended by chains or ropes, sometimes reflect as to what will happen to them in the event of such chains or ropes giving way or failing. They do not allow any feeling or question of failure to trouble them when they are unable to see the mechanism which operates the lift ; they simply conclude that it is something they cannot understand, because it is not imme- diate y before their eyes. To this class of person a ram lift PLATFORM LIFTS. 133 is quite safe, and greatly to be preferred to any suspended type ; whereas the fact remains on record that the most serious accident which has happened to any public lift occurred upon a direct-acting or ram lift. There are elements of danger everywhere, but probably the safest place in the world, taking the number of persons carried into account, and the careless handling that controls the working of lifts generally, is a car of a modern high-class suspended elevator. A good lift provides for every contingency which can befall it : excessive speed, overloading, failure of the valve, breakage of the ram or suspending cables all of these are properly anticipated by the high-class maker ; but, as in the case of every refinement, they have to be paid for in the First instance. Here it is that cheap and common lifts come in and secure a market ; they are capable of raising as much load, and at as quick a speed, as the good and safe lift, while they cost about 50 per cent. less. The manufacturer who would scorn to ride in a vehicle which did not possess absolute strength and finish in all its parts, and who would not countenance any suggestion that unlicensed vehicles should ply for public hire, does not hesitate to erect in his manufactory the cheapest lift that he can buy, knowing also at the same time that the elements of safety are not provided for in the common class of lift. Government inspection should protect the workpeople when the indifference of the employer fails to do so. In our description of lifts, we shall divide them into the two before-mentioned classes, viz., direct-acting or ram lifts, and suspended lifts. These two classes are often spoken of according to the kind of balance employed, as a weight- balanced ram lift, or hydraulic-balanced ram lift. There are four leading styles of balancing arrangements in vogue for lifts ; the two styles most often used are known as the dead weight and the hydraulic balance, while the two less frequently used are the combined weight and compensating balance and the combined hydraulic and compensating 134 HYDRAULIC POWER ENGINEERING. Fig. 80. . PLATFORM LIFTS. 135 balance, the word compensating being used to indicate that the balancing arrangement provides for the varying water displacement of the lift ram while moving in or out of the cylinder. The conditions that determine the description or style of lift most economical to adopt to meet given requirements are in themselves of such a varying nature as not to admit of classification, depending as they do upon the weight to be lifted, the nature of the weight, the height of lift, the kind of building it is to work in, the nature of the ground the building stands upon, the water pressure at the base- ment of discharged level, also whether the lift can be worked by an engine and pumps. Generally loads of from 3 tons and upwards are most conveniently dealt with by a ram lift ; for lighter loads a suspended lift may be used. It is not usual to put a compensating balance to suspended lifts or ram lifts of short travel, but they are of great economy in a ram lift of long travel, say from 30 feet and upwards, especially when the working pressure in the lift cylinder is small. Figs. 80 and 81 are a sectional elevation and plan of a dead-weight balanced ram lift for a warehouse consisting of a wooden platform with guard rail upon three of its sides ; the platform is bolted to joist or girder iron, and mounted upon a cast-iron platten A. The platten is strongly bolted to the end of a truly turned and polished ram B, made up in lengths of cast-iron piping joined together by screwed nipples c, the pipe ends being tapped to receive them. A blank flange is bolted to the end of the last length of piping to form the end of the ram. The cylinder is made by bolting together pipe lengths D, with a blank flange at the end, the upper end being bolted to the foundation plate E, which is cast with a recess forming an annular space round the ram in excess of that between the ram and cylinder. The foundation plate is provided with a flange to which is bolted the stuffing box, and it also carries the branch to 1 3 6 HYDRAULIC POWER ENGINEERING. which can be attached, in most cases direct, the valve F. The rope G from the valve wheel parses round pulleys and up each front corner of the well-hole. Clips are attached to the rope at positions near to the highest and lowest positions of the ram against which a striking bar connected to the lift platform can act, so that when the ram nears its extreme position at the top or bottom of its travel the valve is auto- matically closed to pressure or exhaust respectively. The Fig. 81. slippers or runners which work against the guides are generally cast iron, made an easy fit upon the guides H, which may be made of hardwood, planished bar or T-iron, and are firmly secured to the walls of the well-hole. The adjustable balance weights K are placed in cast-iron frames. These frames run upon T-iron or other guides bolted to the wall of the well-hole, and are connected to the lift by means of wire ropes or chains passing over pulleys on opposite sides at the top of the well-hole. It is convenient at this point to call the attention of the PLATFORM LIFTS. 137 reader to a few points in lift design, which materially affect the working arrangements when a load is wheeled on to the platform of the lift ; the weight first comes upon the edge of the platform, tending to tilt it, the ram resists this tilting action by a bending stress on cross-sectional planes, and the resistance of the ram to cross breaking ought to be some T< Fig. 82. six to eight times as much as the stress induced by placing the whole load lifted at the most distant edge of the platform. Assuming the working pressure to be high, and the ram consequently small, the size of the ram would be insufficient to resist the bending stress- induced by the tilting of the platform, and a wrought-iron braced framing L (Fig. 82) 138 HYDRAULIC POWER ENGINEERING. must be provided to carry the platform, having the guides placed close to the top and bottom of the framing. The tilting of the platform is now resisted by the guides, leaving the ram to support the dead load only. When a cage or cabin is used in place of a platform, this braced iron framing is not needed, the bracing in the cage or C,bin being sufficient to prevent bending of the ram. In making a long ram, by jointing together 10 or 12 foot lengths of piping, the connecting nipples should be so screwed as to leave some 3 inches in the middle of their length plain, and the inside thread at the end of the pipe lengths should be turned off for a distance of i j inches from the end, and made a good fit on the unscrewed part of the nipple. After screwing the pipe lengths together, the ends of each length should be drilled, the hole rhymered, and a steel pin driven or screwed in to prevent the nipple from unscrewing. For the purpose of calculation, the diameter of such a ram built up with lengths of pipes, and considered as a long column supporting a load, may be taken very approxi- mately as equal to half the sum of the diameter of the nipple at the bottom of its thread and the out-diameter of the pipe of which the ram is made. In small diameter rams, as shown in Fig. 82, the screwed nipple is turned out of the solid ram, and its diameter may be .66 to .70, the diameter of the ram. If therefore it- is required to ascertain the supporting strength of the ram as shown in Fig. 82, the equivalent diameter of a long solid column of equal strength would be to --' -^- or .83 to .85 times the diameter of the jointed or built up ram. In many ram lifts the pressure or junction pipe from the valve connects direct to the side of the cylinder, and in order that the full waterway of the pipe may be utilised the clearance between the ram and the cylinder should not be less than quarter the diameter of this junction pipe; thus with PLATFORM LIFTS. 139 a 2, 3, and 4 inch junction pipe the clearance between the ram and the cylinder requires to be J, f, and i inch respec- tively. A i-inch clearance makes a very large cylinder, and as | -inch clearance is sufficient for all rams of medium size, and of any run out, it is most economical to cast an enlarge- ment or recess round the bore-hole at the bottom or under- side of the foundation plate, and to connect the pipe from the valve to this recess as in Fig. 80. The size of valve suitable for a medium-pressure ram lift need never exceed one quarter the diameter of the ram, and when the diameter of the junction pipe between the valve and the cylinder is in this proportion the velocity of the water in the pipe is sixteen times the velocity of the ram. In any direct-acting lift when the ram is down, the water pressure acting on the ram is greater than when the ram is up by a column of water equal in amount to the displacement of the ram, and as the ram rises this column lessens by the amount the ram has risen. We will assume an allowance of i foot per second as the speed of the ram in the final part of its up stroke, or when it has nearly completed its run out, the platform being weighted with its full load, and the head of water absorbed in overcoming frictional resist- ances in the pipes and valve, and in imparting the velocity to the water as 1 2 feet. This is most conveniently allowed for by reducing the working pressure by 5 Ibs. per square inch when calculating the size of the ram, therefore in our examples we shall assume 5 Ibs. as equivalent to the head of water absorbed in frictional and other losses. When the high velocity of the water in the pipe joining the valve to the cylinder is considered, it is not surprising that the too sudden closing of the valve to pressure induces vibratory stress in the water, and consequently in the ram, giving the latter jerks or shocks when stopping. It should be the aim of every lift-maker to so construct his lifts as to reduce to a minimum these jerks, especially in lifts for hospitals and hotels. 140 HYDRAULIC POWER ENGINEERING. The best preventative to jerks produced by closing the valve to pressure is to bolt the valve direct on to the cylinder. On the majority of lifts this cannot be done, therefore the connecting pipe between the valve and cylinder should be as large in diameter and as short in length as possible, hence a 2 or 3 inch valve requires a 3 or 4 inch connecting pipe. To further reduce shock, the port-holes in the valve should be made with V-shaped openings so as to admit of very gradual opening or closing as described in Chapter VIII., while in large valves for low pressure it is advantageous to insert in the valve body a bye-pass valve to act as a shock valve to reduce the intensity of the shocks or jerks of the ram. Some designers arrange an air vessel on the con- necting pipe between the valve and cylinder, which will also reduce the intensity of the shocks of the ram, but nothing in the shape of shock valves, or air vessels, is so effective as making the lift valve to give a very gradual opening or closing of the port-holes, while connecting it to the cylinder by a large diameter pipe of very short length. It is not usually considered necessary to apply safety gear to ram lifts, as the only time an unbalanced ram lift could fall at a dangerously rapid pace would be in the unlikely event of the bursting of the cylinder, junction pipe or valve. This contingency should be impossible if the usual liberal margin of strength or factor of safety is adopted, and the pipes so protected that they cannot be damaged by falling weights. Drain cocks to the cylinder, pipe and valve, to drain off all the water in frosty weather, or for repairs, should always be provided. The ram of a direct-acting ram lift, either unbalanced, or with a hydraulic balance, acts as a column in supporting the load, and is in compression, but if we attach to the ram platten or platform, by means of wire rope or chain, balance or counterpoise weights, an altered condition of stress is set up in the ram. For a considerable portion of its length PLATFORM LIFTS. 141 from the top, the ram, instead of supporting the load as a column, is in effect really hanging or suspended from it. Part of the ram is always in tension, and another portion is always in compression, while the neutral or dividing plane, where the tension ends and the compression begins, is con- stantly varying in position according to the pressure on the ram. Should the ram from any cause become cracked, and thus break above the neutral plane, or should the means of connection securing the platform to the ram give way, then the platform would be violently dragged up to the top by the balance weights, and serious damage, of course, would result. An accident of this character happened to a lift at Paris, where several passengers were crushed to death. This accident has had a great deal to do with the move- ments which have been initiated by some inventive engineers to prevent the possibility of such partings of cage and ram ; although it is very much to be doubted whether our English practice of firmly constructing ram lifts could even have given room for such an accident. The application of high pressure to direct-acting lifts is a matter which produces great economy in their working, seeing that but small and slender rams are capable of carrying a comparatively heavy load. These small rams at first give rise to a suspicion of weakness and danger, but from the examples to be seen on every hand working, particularly in London in connection with the London Hydraulic Power Company, we can easily prove their strength, and thus obtain confident assurance of their fitness for the duties they have to perform. Messrs Easton & Anderson supplied a lift for Queen Anne's Mansion, Westminster, where a 5-inch diameter of ram, having a stroke of 101 feet, is working still with a pressure of water due to a column 142 feet high, or about 62 Ibs. per square inch upon the area of the ram. This ram weighs 2,817 Ibs., and raises a load less than its own weight ; thus the upward pressure upon this ram is the pressure per square inch multiplied by the area of the ram 142 HYDRAULIC POWER ENGINEERING. in inches that is, 23.7 square inches x 62 Ibs. = 1,469 Ibs., which is a little more than half the weight of the ram itself. It seems remarkable upon the first glance that such slender rams can safely support a load when standing so far out of the point of rest, as it were, of the ram, which we appear to imagine as a column ; but the fact is the rams are seldom under compression, seeing that they weigh more than the load that they have to lift, together with the surplus weight or preponderance which is necessary to cause them to descend when the cage is empty ; consequently the water pressure only serves to relieve the weight of the ram, and not to support it altogether. In all lifts the ram should be screwed and pinned or otherwise securely fastened to a cast-iron cap to which the joist irons can be firmly bolted, the latter making a support to which the wood forming the platform or cabin can be secured. The wire ropes or chains of the counterpoise weights should be securely attached to the ends of the joist irons, and never in any case to the wood forming the plat- form, nor to the top or sides of the cage or cabin. In the following examples R = run out of ram in feet. / = length of ram in feet. p = nett working pressure in pounds per square inch at top level of cylinder. W = load to be raised. W x = load to be raised including weight of cabin or platform. x = diameter of ram in inches. Then for an unbalanced cast-iron ram lift This is the approximate value of x because, after filling in the valves and solving for x, it must be divided by a suitable PLATFORM LIFTS. 143 coefficient from Table IV. to allow for the stuffing-box friction, and thus the correct value of x is obtained. It should be noted that in the above formula it is assumed that the weight in pounds per foot run of a finished cast-iron ram x 1 does not exceed . Hollow wrought-iron rams are not so 2 common as cast iron ones, and where their finished weight in pounds per foot run does not exceed , as they need not, 4 we have for an unbalanced wrought-iron hollow ram lift / 4\V 1 ~ The value of x thus obtained to be corrected for stuffing- box friction by dividing it by the proper coefficient as in the previous case. If the ram is of small size, and the weight per foot is represented by x 1 Ibs., the formula becomes Wi .78 54 /-/ CASE I. Find the diameter of a cast-iron ram for an unbalanced lift to raise 14 cwt. 50 feet high, water pressure 45 Ibs. per square inch, platform to weigh 8 cwt. Here we have / = say 53 feet, / = 45 - 5 = 40, \V 1 = (i4-f-8) 112 = 2464 Ibs., then 72x2464 V 62.8- 53 =22 ' 42 > for a 22-inch diameter ram the coefficient of efficiency = .99, hence 22 -4 2 _ 22.55, the corrected value for x. As this is \/-99 a little over 22^ inches diameter, we should put in a 23-inch ram. Now this would be an absurdly large ram to employ for only raising 14 cwt. 50 feet high, and our reason for noticing it is to demonstrate the saving of water effected as 144 HYDRAULIC POWER ENGINEERING. this common type of lift gradually approaches in design the more perfect form. A diminution in the size of the ram can be made as some of the platform and ram weight can be balanced, as shown in Fig. 80 ; we cannot balance all the weight, as some weight must be left in the ram in order that it may descend in the cylinder and force the water through the valve to exhaust when the lift is being lowered without any load upon the platform. The size of ram for a balanced lift is given by the following formula W .78 54 (^-.434R) After solving for x its value must be corrected for stuffing- box friction as before. CASE II. Same as Case I., but the ram and platform to have as much as possible of their weight balanced, as in Fig. 80. Here we have R = 50, p 45 - 5 = 40, W = 14 x 112 = 1568 *- /I568 428. V 14-36 On referring to Table IV. we find the efficiency of a lo-inch ram working through a stuffing box = -98, hence the corrected value of x = '7* ( As this is the diameter of the ram on the assumption that there is no friction in the balance ropes and pulleys, the diameter of the ram as found by the above rule must be increased to allow for the packing in the gland being screwed unnecessarily tight and for the friction of the balance-weight ropes, or chains, over their pulleys, for which we will add 20 per cent, to the ram area, giving in round numbers an nj-inch ram. The amount of counterpoise or balance weight required is equal to the weight of the ram and platform, less the weight of the column of water dis- placed by the ram, and the additional allowance to over- PLATFORM LIFTS. H5 come the friction of the stuffing box, etc., during the descent, equivalent to 10 per cent of the balance weights. Ram =3,498 Platform - 896 4,394 water column 2,235 2,159 Less 10 per cent. 215 i,944 Ibs. With the water pressure of 40 Ibs. the ram would refuse to rise right to the top, but as the lift began to slow down this pressure would rise, approaching the maximum of 45 Ibs. A pressure of 42 Ibs. is sufficient to send the ram to the top. Fig. 80 shows a convenient form of balance, as it admits of easy adjustment of the weights. In the case just considered, the weight of the water column displaced by the ram had to be left unbalanced in order that the ram should descend, and in raising the lift the whole of this dead or displacement weight has to be lifted by the pressure water. In order to obviate this, the balance weight is sometimes connected to the platform by heavy link chain, so that as the ram rises the chain in passing over its support- ing pulley at the top of the well-hole gradually increases the weight of the counterpoise, and at the same time reduces the weight to be lifted by an equal amount, and thus balances the water column. The proper weight per foot of these heavy chain con- nections is half the weight of the water column per foot. If P represents the pressure on the ram area, W the useful load to be lifted, and w the weight of the water column displaced by the ram P-W-* K 146 HYDRAULIC POWER ENGINEERING. This result may at first seem paradoxical, as P is evidently less than W, but it is the same as if the pressure acting on the ram is represented by the head acting on the ram at half stroke, thus The diameter x of the ram is given by the following equation W . 7854 (/ + .217 R) The ram area given by the above equation must now be increased by 66 per cent., to allow for stuffing-box friction and the friction of the chains and wheels, and a margin to cause the lift to descend empty. The balance weights must be the same as the total weight of the ram and platform, less the weight of the compensating chains and 10 per cent, for friction and margin to cause the lift to descend empty. CASE III. Same conditions as Case I., but with a com- pensating balance. 1568 Add 66 per cent, to area and x = 8". Balance weights : Ram= 1,700 Platform = 896 2,596 Less compensating chains ( L \ 531 2,065 Less 10 per cent. 206 i, 860 Ibs. These weights leave a margin of 235 Ibs. to overcome friction when ascending with full load, and 205 Ibs. when descending. PLATFORM LIFTS. 147 When the weight to be raised is heavy and the available working pressure small, the size of the ram, balance weights and chains, and overhead wheels or chain pulleys, becomes very large and clumsy. For large weights it is advisable to use an intensifier, and by loading its ram with weights, to convert it into a hydraulic balance. Such a machine is shown in Fig. 83, in which A is a hollow ram, sliding over the fixed ram B, and working in the cylinder c. To the ram A can be attached the adjustable weights F, and the fixed ram B is tied to the cylinder c by the guide bolts G G. The inside of the ram A communicates through the opening D direct with the lift cylinder, and the displacement of the ram B is of sufficient capacity to contain the displacement water when the lift ram is down. The valve is connected to the cylinder c at E, and sufficient weights are placed at F to prevent the lift ram descending too rapidly. When the lift ram is down the displacement water fills the inside of the hollow ram A, which is then quite home in the cylinder c, and upon opening the lift valve the pressure enters the cylinder c, forcing the ram A out, and consequently the ram of the lift. As the balance ram A runs out of the cylinder c, its end pressure gradually increases in proportion to the increased head of water. By suitably proportioning the diameters of the lift ram and ram A, the variation of the load to be lifted, caused by the varying water column in the ram cylinder, may be balanced at all parts of the stroke. The correct diameters for the lift ram and the ram A can be ascertained as follows : Let W = net load to be lifted in pounds. / = water pressure per square inch at level x y. R = run out of ram in feet. R! = run out of ram A in feet. r = ratio of area of ram B to lift ram area. x = diameter of lift ram in inches. y = ratio of area of ram A to area of lift ram. 148 HYDRAULIC POWER ENGINEERING. 4- 11 U 223 Fig. 83. PLATFORM LIFTS. 149 In designing, the top level of the lift ram, lowest level of ram A, and exhaust outlet should all be on line x v. These conditions are assumed in the following equations. The level of the ram A may be varied, but the balance weights F then require readjustment. = / W V .8 7854AT Balance weights = r x (platform + ram -- water column). The balance weight thus found must include the weights F, the cylinder A, and the water contained in the annulus between A and I?, and lying below the line x Y. CASK IV. Same conditions of load and lift as Case I., but to be balanced by the above hydraulic method. W= 1,568 Ibs. Platform = 896. R = 5o feet. / = 45 -5 = 40- Select r=4. Then R x = 12.5 feet. (5o+-i2.5). 43 To find diameter of A, ^10.25 x 19.9 Diameter of B = 2 x 3 J" = 6J". 150 HYDRAULIC POWER ENGINEERING. Allowance must now be made for friction, and diameter of A increased accordingly. Friction of lift ram : W= 1,568 Platform = 896 Ram, 3j" diam. hollow, -J" thick = 760 2,224 4 per cent. = 88.96 Friction of ram B = 2 J / of - = 45 .... r / r 6400 friction of ram A= i / of = . 16 Total 150 Friction of rams descending empty = in Hydraulic friction of descent = 50 Pressure on ram A = 6400, which has to balance 1568 x 4 = 6272, leaving a margin of 128, hence 200 Ibs. must be added, requiring an additional area of - = 5 inches. The ram A 4 must therefore be increased to 14 J inches. Balance weights : Platform = 896 Ram = 760 1,656 Less water column 178 1,478 4 5>9 12 Owing to the increase of the area of the ram A, a dis- crepancy of about 25 Ibs. occurs, which can be rectified by reducing the balance weights. PLATFORM LIFTS. 15! The word efficiency as commonly applied to lift work has a very vague meaning ; its meaning in this chapter is, how- ever, defined as the ratio of the theoretical quantity of water required to raise the load to the actual quantity the lift con- sumes. The following table shows at a glance the efficiency of the direct-acting ram lifts in the cases that have just been considered. The theoretical quantity of water at 45 Ibs. per square inch to raise 14 cwt. 50 feet high is 75.5 gallons. Case. Description. Gals. Efficiency Ideal lift or theoretical - 75-5 I IV. Compensating hydraulic balance 95-7 79 III. Compensating and counterpoise balance - 109.0 .69 It Counterpoise weight only - - - 225.0 339 With higher and more suitable pressures the efficiency of ram lifts averages from .75 to .80 per cent., the latter amount being only met with in lifts of good design and build. Fig. 84 shows Ellington's hydraulic balance, which con- sists of a balancing cylinder M, connected by distance bolts end to end with the larger working cylinder N. There is a piston to each cylinder, fitted with a leather packing, and connected by a common rod D, working through stuffing boxes in the cylinder covers. The lift cylinder is connected by the pipe H to the annular space E F, which, when the piston G is at top of its stroke, is equal in capacity to the displacement of the lift ram. The annular area L of the lower piston is sufficient when subjected to the working pressure to lift the net load and overcome friction of both the up and down strokes, whilst the full area of the upper piston G is calculated when subjected to the working pressure to balance the weight of the cage and ram less the friction 152 HYDRAULIC TOWER ENGINEERING. Fig 84. Fig- 85. PLATFORM LIFTS. 153 of the down stroke. This piston is subjected to the water pressure at all times. If the lift ram is assumed to be at the bottom of its stroke, then, on the starting valve being opened, pressure water is admitted to the cylinder c, and the two pistons G and L commence to descend, forcing the water from E E through the pipe H to the lift cylinder ; the lift ram is thus caused to ascend, and in doing so requires increasing pressure to compensate for the reduced displacement. This increase of pressure is supplied by the head of water accumulating on the two pistons G and L. When the exhaust is opened the water from c c only passes away, the water at B being simply forced back into the pressure mains. To make good the leakage the pressure water can be admitted by F under the lower piston when the lift ram is at the bottom of its stroke ; thus water will flow from B past the leathers into the annular space E E and supply the deficiency. If the parts of this apparatus are properly proportioned, the lift ram and the balance pistons are in equilibrium for every part of the stroke. The only serious criticism to be offered to this form of balance is the use of internal pack- ings, it being a sine qua non in high-class design to use ex- ternal packings wherever possible. If in Fig. 83 two inverted rams had been used, in place of the weights F, always open to pressure, an inspection will show that the two systems are practically identical. The lift ram (Fig. 83) would in this case require to be of altered diameter to allow for the weight of water in the two added rams. When the working pressure is sufficiently high, such as 750 Ibs. per square inch as supplied by the London Hydraulic Power Company, it frequently happens that the size of ram re- quired to overcome the load is too small to sustain the load when considered as a column. The hydraulic balance shown in Fig. 85 is much in favour under these circumstances. The water column is unbalanced in this type. A hollow ram A 154 HYDRAULIC POWER ENGINEERING. works through a stuffing box in the cylinder B. The cylinder B is connected by the tension bolts E E to a crosshead F carrying the fixed ram c, working through a stuffing box in the ram A. The ram A is supplied with a crosshead G carp- ing the weights 11 H, which are proportioned to balance the dead weight of the cage or platform and the ram, less the water column due to the strokes of the lift ram and the ram A and a margin for causing the down stroke. The cylinder B is connected through the port j with the lift cylinder, and has the same displacement volume. The pressure water enters from the lift valve at F. When the lift ram is down the balance ram A is up as shown, and on opening the valve the pressure acting on the area of the ram c forces the ram A into the cylinder B, thus causing the lift ram to run out, and when the valve is opened to exhaust the margin of weight in the lift ram to cause the descent raises the balance ram A to the top of the cylinder B. The area of the ram c must be such that, at the pressure available, the total pressure is sufficient to overcome the useful load together with the column of water of a height represented by the stroke of the lift ram added to the stroke of A, and leave a sufficient margin to overcome the friction of the up and down strokes. When pressure water is not available, cither from want of sufficient height or absence of an existing supply, a ram lift can be worked fairly economically by a steam or gas engine, the engine being employed to drive a small pressure pump which forces water from a tank into a small accumulator which has a pipe connection to the lift valve. A suitable pressure for the accumulator is from 1,000 to 1,200 Ibs. per square inch, and the capacity of the accumulator should be from one and a half to twice the consumption of water for one complete journey of the lift. The pumps should be proportioned to deliver when working continuously a larger amount of water than is required by the intermittent working of the lift, and gear PLATFORM LIFTS. 155 should be fitted such that when the accumulator is fully charged with water the pumps are automatically thrown out of action, thus economising power. A slight fall of the accumulator should bring the pumps again into action. Where steam power is available the Worthington steam pump can be employed to pump the water direct into the ram cylinder, the valve being controlled by the cord passing through the cage. The openings to the lift wells in hotels are guarded with light iron gates which the lift attendant alone can open, while in warehouses a wood guard rail is simply hinged to one side of the lift opening. This rail is lifted up when passing in or out of the lift and then dropped upon its supports. Many attempts have been made to secure the opening and closing of the guard rail or iron gate by the up and down movement of the lift cabin or platform, but it is found that mechanical closing begets carelessness on the part of the attendants. By fixing a vertical balanced sliding door in the opening at the bottom of the lift well, and making a hole in the floor to receive the door, the platform or cabin, in its descent, can be made to depress the door level with the floor, and on the ascent of the plat- form the excess of balance weight will cause the door to rise and guard the well-hole. At the top floor a sliding door can be fixed and partly balanced by means of weights and chains, the top of the cabin or cage being arranged to engage the door in ascending so as to lift it clear of the entrance to the cage, the descent of the cage allowing the door to drop to the floor and guard the well-hole. On the intermediate floors it is most satisfactory to open and close the guard rail or gates by hand. Passing on to consider the second division of our subject, viz., suspended lifts, Fig. 86 illustrates in elevation the more common arrangement of this form of lift. A is an ordinary cabin or cage, well braced and boarded on the three sides, but open in front. To the bottom of the cabin are secured the two girder irons B lying side by side, with sufficient space 156 HYDRAULIC POWER ENGINEERING. Fig. 86. PLATFORM LIFTS. 157 between to receive the safety gear. These girders are secured by tension bolts c c to corresponding girder irons D. At the top of the cabin A, and between the girder irons D, are placed the grooved wheels that convey the wire rope to the safety gear fixed below the cage. Two lifting ropes E are used, one passing to the right hand and the other to the left hand of the cage, and thence to the safety gear. Four slipper guides are fixed to the cage, sliding up and down upon the hardwood guides F F, which are securely attached to the brickwork at the sides of the well-hole. The ropes E pass round the overhead pulleys G G to an ordinary hydraulic multiple hoist shown at H. This hoist is made in exactly the same way as those to be described in Chapter XL, and is bolted to the wall with the ram working downwards. To the crosshead are attached the balance weights j, sufficient to almost balance the weight of the cage. The valve K is placed in the well-hole under the cabin as in the case of ram lifts, and the starting rope passes down through the cage on each side of the well-hole, and is con- nected to the pulley on the valve. Stops are attached to the starting rope, so that the cabin when nearing the termination of its travel operates against these stops and automatically closes the valve. The size of the valve need not, as before stated, exceed one quarter the diameter of the hoist ram, and the weight of the ram, crosshead, pulleys, and balance weights should be such as to admit of the cabin descending when empty at the rate of i foot per second. When the cage or cabin is at the bottom level the ram of the hoist is up in the cylinder H, and on pulling the rope L to open the valve to pressure the ram is forced out of the cylinder and the cage ascends until, on nearing the top of its travel, it operates on the upper stop on the rope, thus closing the cylinder to pressure. If the rope is pulled further the cylinder is opened to exhaust, and the excess of weight in the cage above the balance weights causes it to descend, 158 HYDRAULIC POWER ENGINEERING. Fig. 87. Tig. 88. PLATFORM LIFTS. 159 pulling the ram back into the cylinder. On nearing the bottom the cage operates on the lower stop on the rope, closing the valve to exhaust. To secure the efficient work- ing of this lift, all the precautions mentioned at the com- mencement of this chapter must be observed. The correct size of rope and its friction, together with the necessary size of ram for the pressure available, will be considered at the end of this chapter. Fig. 87 illustrates a high-class passenger lift consisting of a cabin A made of pitch pine, walnut, oak, or mahogany, and having its interior well upholstered and sometimes mirrored. The girder irons B are connected by the bolts c c to the ends of the cross girder D at the top of the cabin. This girder is made in two parts firmly bolted together, and carries the grooved pulleys E, which deflect four supporting wire ropes, two to the right and two to the left of the cage, to the safety gear fixed underneath. The ropes E pass round the overhead pulley G down to the hydraulic multiple hoist shown at H, which is bolted to the wall at the back of the well-hole with the ram working downwards. The starting rope L passes down one side of the well-hole through the cabin to the wheel on the valve K, and returns by the other side of the well-hole between the side of the cabin and the wall. The working of this lift is precisely similar to the one pre- viously described, and the difference in construction of this multiple hoist, viz., placing the rope wheels in line with each other instead of side by side, as shown in Fig. 86, is for the purpose of economising space in the well-hole, and thus allowing a roomy cabin to be used. The type of hydraulic multiple hoist shown for suspended lifts in Figs. 86 and 87 answers well for water pressures vary- ing from 150 to 1,200 Ibs. per square inch; but for less pressures better results are obtained by using the hoist illustrated by Fig. 88, which is largely used. 160 HYDRAULIC POWER ENGINEERING. The arrangement consists of a cylinder A truly bored and fitted with a leather or metallic packed piston B, having two piston rods c c working through hemp packed stuffing boxes in the cylinder cover E, and connected to a crosshead carrying the balance weights D and the pulley F. The cylinder has at each end branches G G. The lower branch connects direct to the valve K, while the upper branch con- nects to the pressure pipe j, and is not controlled by the valve K. This lift cylinder is generally placed on one side of the well-hole on the basement floor level, and the wire lifting ropes pass from the cage round the overhead pulley at the top of well-hole, and descending pass round the pulley F and upwards to the anchorage at top of well-hole. The action is as follows : When the piston is at the bottom of the cylinder, as shown, the cabin is at its highest level, and on the valve being moved by pulling the rope upwards the lower branch G is opened to the pressure pipe j, and the pressure water is admitted to the under side of the piston B. The area of the top side of the piston B is less than the area of the under side by the area of the rods c, hence there is an upward pressure. This pressure, together with the excess weight of the cabin over the balance weights D and piston B causes the cage to descend, lifting the piston B. The water passes from the top of the piston through the valve, and fills the space below the piston. On the cage nearing its lowest position a stop on the valve rope L is operated, causing the valve to be closed. Upon pulling the rope further, the lower branch G is opened to exhaust, and the water pressure acting upon the top side of the piston forces it down, thus raising the cabin. Various kinds of safety gear have from time to time been introduced for suspended lifts, many of which are absolutely worthless. Fig. 89 illustrates a well-known type of safety gear suitable for light weight passenger lifts. The hardwood guide A runs from top to bottom of the well-hole, and is en- PLATFORM LIFTS. 161 gaged by the slipper guides bolted to the sides of the cage. The bracket u is bolted to the under side of the cabin, and carries the tension bolts c c connecting this bracket with the cross girder over the top of cabin. Two bell crank levers D D are pivoted to the angle plate B, their longer arms being joined together by the bar E, which is provided with joggles for engaging the corresponding projections on the eccentric cams F F. These cams are keyed fast upon the ends of two shafts running under the cabin, and supported by bearings formed in the angle bracket B. At the other end of these L 162 HYDRAULIC POWER ENGINEERING. shafts two similar cams are keyed, and the shafts being provided with short levers H, that are linked together by the bar G, any movement of one shaft produces a corre- sponding movement in the other. The cabin should be suspended by four ropes, two of which pass down each side of the cage, as previously described. These two ropes are anchored by means of shackles to the short arm of the bell crank levers D D. The weight of the cabin is thus divided equally between the four ropes, which are adjusted in length so that the long arms of the bell crank levers D D hang vertically. The cams F F are just clear of the guide A ; but upon any one of the ropes stretching or breaking the tension of the adjacent rope pulls the bell crank levers D D out of the vertical, thus pull- ing over the connecting link E, and causing the cams F F to engage the guide A. The frictional resistance of the cams F F on the guide causes the cams to revolve on their shafts, and firmly grip the guide "A, thus supporting the cage. By this arrangement the breaking of any one of the four suspen- sion ropes brings into action the four cams. Fig. 90 illustrates the Otis safety gear. A is the hard- wood guide running from top to bottom of the well-hole. Two rocking levers B are provided, turning on the pins c carried by castings bolted to the wood crossbeams upon which the cabin rests. * To the side of the wood beam is bolted the bracket F, carrying the shaft G running under the cabin, and supported at the other end by a similar bracket bolted to the beam. To each end of this shaft are keyed the strikers E, which are actuated by the rocking levers B through the medium of the set screws H H. The cage is suspended by four ropes, two of which pass down each side of the cage, and are fastened to the suspending eyes of the bolts K K. These bolts connect to the lever B at an equal distance on each side of the pin c, and by adjustment of their nuts the lever B is placed horizontally. Should one of the ropes stretch or break while the cabin is travelling up or PLATFORM LIFTS. I6 3 down, the lever u, being relieved of the pull of the broken rope upon one arm, is tilted up by the pull of the remaining rope upon the other arm. This movement of the lever K actuates the striker E, and causes it to push the wedge D up, 164 HYDRAULIC POWER ENGINEERING. thus preventing the further descent of the cage. The fric- tion of the back of the wedge against the casting being much less than that of the face of the wedge against the guide, the weight of the cabin assists in fixing more securely the wedge against the guide. The two kinds of safety gear described are independent of the elasticity of a spring for their action, and from the fact that they have few and simple parts they are not likely to become clogged with dirt, as often happens with a badly thought out gear. The number of lifting ropes for suspended cabins or cages varies from two to eight, and as the safety gear re- quires four it becomes necessary to either increase or reduce the number. This is easily done by introducing a crosshead having three holes for the attachment of ropes. Two ropes are attached, one at each end, and pass off in one direction ; while a third rope is attached in the middle, and passing off in the opposite direction, resists the tension due to the other two. In order to provide against the possibility of a dangerously rapid descent of the cage, due to the valve being opened too wide for the load being raised or lowered, a centrifugal governor, which is actuated by a light endless wire rope or belt suitably attached to the safety gear and passing over idle pulleys, is used. Should the governor revolve too quickly, the rope is retarded by a friction brake, and by the tension thus produced the rope is caused to operate the safety wedges, and check the descent of the cage. To ensure a long life for the wire ropes of a suspended lift the stress on the wires due to tension, together with the stress due to the wire bending round the smallest pulleys, should not exceed the stress which experience has shown the wire will stand frequently repeated. For steel wire of aver- age quality this stress may be at least 70,000 Ibs. per square inch. Again, when life would be jeopardised by an acci- dent, as in a lift or crane, the working stress should nut exceed one-eighth the breaking stress of the rope. PLATFORM LIFTS. I6 S The latter consideration will enable the size of the rope to be determined, while by the former the correct size of the wire of which the rope is to be made can be ascertained when the diameter of the smallest wheel over which the rope passes is known. Assuming the breaking weight of good plough steel wire rope to be 150 tons per square inch of metallic section, then the ratio of the diameter of the wires of the rope to the diameter of the smallest wheel round which the rope passes should be about T j^. If the ratio is much larger than this, and the steel of which the wires are made be not of good quality, rapid deterioration of the rope commences, and rupture will take place if the rope is not replaced. Table VII. gives the breaking weight in tons of good average quality plough steel wire ropes : TABLE VII. BREAKING WEIGHT OF STEEL WIRE ROPES. Diam. of rope in inches A I -is i A 5 a S 7 8 I Circumference in inches i i A If it if 2 2* 2| 3 Weight in pounds per fathom - ii IT** i A 2* 3 4 Si 7i 'o Breaking weight of rope in tons - 4 5^ rt IO n| i5i 2li 28f 40 When the maximum stress induced in the wires of a rope passing round a pulley does not exceed 70,000 Ibs. per square inch, the power expended in bending the rope on to the pulley is largely given off again upon the rope leaving the pulley. Fig. 91 illustrates part of a grooved rope wheel, and A B is a horizontal line passing through the centre of the wheel, and c c is the centre line of the wire rope passed round the wheel as shown. It is assumed that this centre line does 1 66 HYDRAULIC POWER ENGINEERING. X \ Figs. 91 and 92. PLATFORM LIFTS. 167 not alter in length when the rope is bent round the wheel. This erroneous assumption does not perceptibly affect the results. Thus it is evident that the wires below the centre line c c of the rope must accommodate themselves to a less circumference than the wires in a plane normal to the paper ; whereas those outside of the centre line accommodate them- selves to a larger circumference. The wires accomplish this in the former case by bulging or spreading out laterally and creeping, and in the latter by straightening and draw- ing in to the centre of the rope. Thus the rope circular below A B before it touches the wheel becomes slightly oval above A B, where it lies in the groove, as shown by the full line D. The distance between n and the dotted line E indi- cates the extent to which the rope is distorted out of the true circle. Thus the work lost in bending a rope round a circle is the frictional resistance of the wires sliding upon each other in the act of accommodating themselves to the varying circumferences in which they are forced to lie. Let D = diameter at bottom of the groove of the rope wheel in inches. ,, */-- diameter of the wire rope in inches, and if the coefficient of friction = .2, the efficiency of a rope passed half round a wheel is The efficiency for various sized ropes passing half round pulleys of different diameters calculated by this formula are given in Table VIII. Fig. 92 illustrates a square chain wheel with a chain A B suspended from it. In turning the wheel in the direction of the arrow a quarter of a revolution the links A and n each turn a quarter round on their supporting links c and D. Thus when the wheel makes a complete revolution the fric- tional loss of the chain is the same as that of a link turning 1 68 HYDRAULIC POWER ENGINEERING. twice round an iron rod of circular section equal in diameter to the bar iron of which the chain is made. Now this holds true whatever may be the size of wheel, pitch of chain, or diameter of chain iron, so that we get for the efficiency of a chain lapping half round a wheel the formula The coefficients of efficiencies for different sizes of chain passing half round pulleys of varying diameter calculated by this formula are given in Table VIII. PLATFORM LIFTS. 169 TABLE VIII. COEFFICIENTS OF EFFICIENCY OF STEEL WIRE ROPE AND SHORT LINK CHAIN (FRICTION OF PIN NOT INCLUDED). Centre to Centre of Rope or Chain across Diameter of Pulley. Diameter of Rope or Chain Iron in Inches. i i i i 1 1 1 I i o c CJ | i i tf 1 I c a & G 'J5 i .5 CJ ! c '3 5 c CJ 2 inches - - 3 ., ' - 4 - - 5 ) - - 99 99 99 99 97 .98 .98 99 .98 .98 99 95 .96 97 .98 .98 97 .98 .98 95 .96 .98 95 6 ,, .98 99 97 .98 .96 .98 95 .98 95 .. 8 - - .98 .98 99 97 .98 .96 .98 .96 .98 95 10 ,, - - 99 .98 .98 99 97 .98 97 .98 .96 .98 .96 12 ,, - - .98 .98 97 99 97 . 9 8 97 .98 .96 4 ii .98 .98 .98 97 99 97 .98 97 16 - - 18 ,, 20 ,, - - 99 .98 .98 .98 .98 08 98 08 97 08 99 97 97 c8 08 .98 .98 2 4 .. .. .98 .98 .98 26 3 .. 99 .98 99 .98 .98 .98 .98 .98 08 34 ., 38 - - 4 2 ' - 99 HYDRAULIC POWER ENGINEERING. The formula for the efficiency of a pulley on its axle or pin is the same as for the efficiency of a chain lapping half round a wheel, providing always that the pressure of the wheel upon its axle does not exceed 5 cwt. per square inch (measured on the diameter of the axle), which amount should not be exceeded in lift designing. Table IX. has been calculated by this formula, and for the convenience of readily ascertaining the efficiency of lifts, pulley blocks, etc., the average ratio of the diameter of the pins to diameter of the pulleys is given here : Diameter of Wheels in Inches. I to 1 6 16 24 24 36 Above 36 Average Pin Ratio. i iff i 10 or .125 .10 TABLE IX. COEFFICIENTS OF EFFICIENCY OF PULLEY WHEELS TURNING ON PINS. 1 Ratio Diam. > i of Pin to ! Uiam. of Wheel. | .06 .07 .08 .09 .1 .TI .12 13 .14 '5 .16 T 7 .18 .19 .2 Coefficient I .976 .972 .968 .964 .96 956 .952 .948 944 94 .936 .932 .928 .924 .92 To illustrate the practical application of the Tables, let Fig. 93 represent the pulleys in the ram and cylinder cross- heads of a hydraulic jigger or hoist, the pulleys being spread out to show clearly the varying stresses in the chain. The top circles indicate the chain sheaves or pulleys in the cylinder crosshead, and the chain is anchored to the cylin- der on the right hand, and pays off the left hand top sheave. The bottom circles indicate the pulleys or sheaves PLATFORM LIFTS. 171 in the ram crosshead, which move downwards in the direc- tion of the arrow. Let P = total net power forcing out the ram. / = stress on anchorage chain. M W = weight lifted. N == number of plies of rope or chain. ,, E = efficiency of pin and wheel with rope or chain round half its circumference. 93- When the ram has its full pressure on, but is stationary, p / = , but the instant movement of the ram occurs some of its power is spent in overcoming the friction of the wheel on its pin and the chain on the wheel. Thus in the figure the stress on the anchorage chain would equal /, the stress on the next chain to it would equal E/, again on the next to 1/2 HYDRAULIC TOWER ENGINEERING. that the stress would equal E' 2 /, and so on to the last ply, where the stress would equal E^' 1 ^. Hence W = <->, and /-^ As an example, let the ram of the jigger geared 8 to i exert a pressure of P = 8 tons, then p i ton. The sheaves would be about 14 inches diameter, with about 2 inches diameter pins, so that the efficiency = .94. A chain T 7 g inch diameter would be used, the efficiency of which on a 14- inch sheave = .98, therefore the efficiency of the chain wheel and pin = .94 x .98 = .93 = E. We have W = .93 7 x i, and this equation is easily solved by means of a table of common logarithms- log. .931 = 1.96895 7 1.78265 The corresponding number of which = .6. W = .6 x i =.6 ton. Thus the efficiency of the wheels and chain alone is but .6. Particular attention is directed to the difference in the stresses of the paying-off end and the anchorage end of the chain. The size of the chain or cable should be deter- mined by dividing the total pressure pushing out the ram by the number of chains or rope plies, and not by merely con- sidering the weight lifted. Many breakdowns in hydraulic hoists have occurred through putting in cable or chain of such a size as only to lift the load safely, and omitting to take into account the extra stress induced in the anchorage end of the chain or cable. In an average hydraulic hoist or jigger geared or multiplied up by pulleys 10 to i the stress on the anchorage end of the chain is just twice that on the paying-off end. Many years ago Sir W. (now Lord) Armstrong published the efficiencies of his multiple hoists, which are very con- PLATFORM LIFTS. 1 73 venient for determining approximately the size of cylinder required when the load and working pressure are known. It is advisable to calculate independently the required size of cylinder in each case, only using Armstrong's results given below to aid for first approximation : Direct acting 93 per cent. Geared 2 to JJ 4 5) ,, 6 ,, 10 12 14 16 80 76 72 67 63 59 54 50 CASE V. (see Fig. 86). Required the size of cylinder for a hoist to raise 14 cwt. 50 feet, working pressure 45 Ibs. per square inch. The hoist may be geared 6 to i, and the travel of the ram is then 8 feet - 4 inches. The height of the top of the cylinder H, above the valve K, is nearly 20 feet, corre- sponding to a pressure of 8.5 Ibs., and the working pressure is 45 Ibs. - 5 Ibs. (for speed and valve friction)/ - 8.5 Ibs. = 31.5 Ibs. _ The hoist has to lift the load of 14 cwt. plus the weight left in the cage to bring it down empty, say 2 cwt., and the area of the ram 16x112x6 100 - -- - x ^ =479 square inches, the corresponding diameter of which is 24.75 inches. The size of the rope wheels can now be fixed at 32 inches diameter. Suppose the cabin to weigh 14 cwt., and to be supported by four -inch ropes. The first step in the calcu- lation is to determine the efficiency of the ropes working over five 32-inch wheels upon 2^-inch pins. Consulting Table VIII., we find the efficiency of a f-inch rope on a 174 HYDRAULIC POWER ENGINEERING. 30-inch wheel .99, which is also the efficiency of four ropes on the wheel. The efficiency of the sheave on the pin = .96. Therefore efficiency of the sheaves, rope, and pins of the hoist only = (.96 x .qgy> = ,95^ = .76. The next step is to ascertain how much of the cage weight must be left unbalanced to enable it to overcome the friction to descend empty. The overhead pulleys may be 32 inches diameter, and as the ropes only lap one quarter of the circumference on each, the efficiency of two pulleys is equal to the efficiency of one = .99, and the efficiency of sheaves on pins .96. Therefore, the weight to overcome this = {i-(-99 x .96)} x weight of cage = .05 x 14 x 1 12 = 78 Ibs. Again, the cage has to overcome the friction of the pulley sheaves of the hoist, having an efficiency of .77. Then the weight to overcome this is (i -.77) x weight of cage = .23 x 14 x 112 =360 ,, Finally, the cage has to pull the ram into the cylinder against the friction of its stuffing box, and, from Table IV., this 24 inches diameter ram 90 100 requires 90 Ibs. to move it, so that -> x = 20 Total 458 Ibs. It will be remembered the weight assumed in the trial ram was 2 cwt., whereas we require 458 Ibs. As this is the theoretical amount, we must increase it about 10 per cent., giving say 5 cwt. Then we get for the load to be lifted 14 x 112 - = 1,568 Ibs. Weight left in cage for descent, 112x5 - = 560 Extra pull required to overcome friction of top or overhead pulleys = (load-f weight of cage) x .05 - - = 156 ,, Total weight 2,284 Ibs. PLATFORM LIFTS. 175 Area of ram 2284 x 6 x TOO f . , = sos square inches, 3I-5X77 and correcting this area for the friction of the ram in its stuffing box, * - = 570 square inches, corresponding to a diameter of 27 inches. This would be a very uneconomical arrangement of hoist to adopt under the circumstances, but the case is cited to show how necessary it is to independently calculate the size of cylinder required for each case separately, and not trust to any table of efficiencies, as necessarily such tables can only give average results, thus causing the diameter of the cylinder in some cases to be much larger, and in other cases as, for example, the above much smaller than required. CHAPTER X. WORKSHOP AND FOUNDRY CRANES. HAVING fully discussed the various valves and lifts worked by hydraulic power, we now proceed to examine the hydraulic machinery used for lifting and conveying heavy weights. As a fitting commencement of our discussion, we take the hydraulic jack, as being one of the earliest adaptations of the principle of the hydraulic press to practical use. Fig. 94 is a section of the most common type of hydraulic jack. Water is inserted in the cistern or chamber A through the charging- hole B ; the screw is now replaced in the hole B, and the jack is ready for use. In working the jack, the head c or toe D is placed under the weight to be raised, and the hand lever E is oscillated, causing reciprocation of the pump plunger F. The water in the chamber A passes into the pump barrel through the suction valve G, and is forced out through the valve H into the hydraulic cylinder i, thus causing the ram K to move outwards in relation to the cylinder carrying the head c and toe D. The ram K is prevented from moving too far out by the small hole L, which allows the water to leak from the cylinder i, so giving a signal that the ram has com- pleted its stroke. To lower the ram the thumbscrew M is loosened, letting the water pass back from the cylinder i to the chamber A. A few precautions should be observed in working the jack, If the water has been removed for the purpose of examina- tion or repairs, after refilling, the pumps should be given a few strokes with the screw M loose, to force water into the cylinder i, and so drive the air out. When the ram is in use WORKSHOP AND FOUNDRY CRANES. 177 b HYDRAULIC POWER ENGINEERING. the air screw N must be slacked ; at all other times it should be screwed home. Experiments made at various times to ascertain the effi- ciency of the hydraulic jack give results that agree generally with what might have been anticipated by a theoretical investigation. The accompanying diagram (Fig. 95) shows the general results arrived at by experiment. The ordinates represent the pressures applied to the handle, and the 2 Fig- 95- abscissae the loads to be lifted. The full line or u curve " gives the actual pressures required on the handle of a hydraulic jack, having a mechanical advantage of 64 to i when lifting various loads. The dotted line gives the pres- sures which would be required if there were no friction in the jack. An examination of the diagram shows that a pressure of about 3 Ibs. is required on the handle when there is no load on the jack, showing that this amount WORKSHOP AND FOUNDRY CRANES. 179 of pressure is required to lift the jack and overcome the friction. As the pressure to overcome these resistances will be a con- stant quantity no matter what useful load is being lifted, we can draw the chain line in the diagram parallel to the full line, and indicating the amount of energy lost on this account. It will now be noticed that there is a further loss to be accounted for, which commences at nothing for no load and increases regularly with the increase of load. This extra loss is entirely due to friction in the various parts of the machine due to the increased pressure on the handle, and consequently increased water pressure. The curve in the figure gives an efficiency of 75 per cent, at the full load, which may be taken as a fair average case in designing, though large jacks in very good condition will show an efficiency approaching 80 per cent. When lifting a quarter of the full load the efficiency falls to about 70 per cent, and for smaller loads the jack rapidly becomes an inefficient machine. It must be remembered that the loss of efficiency we have investigated above is not the total loss, as we have neglected the friction on the up stroke of the handle, also the leakage of the pump plunger and valves. We are now in a position to fix the diameter of the ram, length of lever, and diameter of pump barrel, so that the only remaining operation is to ascertain the mass of metal required in the various parts to give sufficient strength. The jack can be damaged by three principal strains, viz. : (i.) The load to be raised by the head may crush the walls of the cistern attached to the jack cylinder. (2.) The load to be raised may shear off the lifting foot at the base of the jack cylinder. (3.) The load may be such that the pressure within the cylinder necessary to raise it may burst the walls of the cylinder. Now Jhe crushing strength of the metal usually employed viz., malleable iron or cast steel is so high that the limits of casting actually ensure that the walls will be strong enough to carry the load. We employ, say, 180 HYDRAULIC POWER ENGINEERING. cast steel, which will have an ultimate crushing strength of 40 tons per square inch, or malleable iron, which will have an ultimate strength of 36 tons per square inch ; and wishing to make the cistern as light as possible for convenience in handling, we find we cannot get walls to be depended upon in castings which are less than T \ inch in thickness. Thus, if we take a 4-ton jack, our cistern is 3! inches diameter, which gives us an area of 3.5x3.1416x^ = 3.4 inches, to carry the load of 4 tons. Other considerations, of course, come in with respect to the arrangement of the metal; but even then the limit of casting ensures us ample margin for safety in working. Similarly, too, the projecting foot, which may be sheared off, is subject to such a light load in proportion to its ultimate strength, that we require to consider chiefly the rough usage which may be given to this projection, and arrange a substantial foot for this, rather than for the actual load to be legitimately lifted by it. The bursting strain in the cylinder, however, we estimate with more care, seeing that the strain is one of tension instead of compression, and that our metal employed may not be equally strong in each case of straining. The diameter of the cylinder being 2 inches, we have a strain of 2 x x pounds per square inch acting to burst the cylinder, while the metal resisting this bursting tendency is the thickness of the wall on each side ; the value of x being that produced by the pump and lever. The load of 8,960 Ibs. has to be raised by the pressure given to the 2-inch ram, This amount we have calculated to be 11,636 Ibs., and as the area of 2 inches = 3. 14 inches, the pressure per square inch becomes 11,636^-3.14 = 3,705 Ibs. per square inch in cylinder; 3,705 x 2 = total bursting pressure within cylinder = 3.3 tons. Assuming the metal to be of steel, moderately good, and with an ultimate tensile strength of 38 tons per square inch, with a factor of safety of 5, we may put 5 \ tons per square inch upon the metal, so that the combined thickness of the walls of the cylinder should equal ^ = .6 of an inch. This WORKSHOP AND FOUNDRY CRANES. iSl would make each wall J inch thick, a dimension which might give trouble in casting in the event of the core slightly shifting, so that | inch is allowed instead. . We will next examine some of the more useful designs of workshop and foundry cranes. Fig. 96 shows a very con- venient form of wall crane. The ram A is fixed to the bottom of the crane post, and has a hole passing up its centre for the entry of the water. The cylinder B carries Fig. 96. the jib c, and moves vertically between the sides of the crane posts so lifting the load, rollers D E being fitted to reduce friction. The crane may be slewed through 180, the water connection having a swivel joint for this purpose. The valves are placed apart from the crane in a position easily accessible to the workman. This type of crane is generally used to serve machine tools, and is made in sizes to lift from 5 cwts. to 10 tons with a rake up to 25 feet. 1 82 HYDRAULIC POWER ENGINEERING. M- ; Fig. 97. WORKSHOP AND FOUNDRY CRANES. 183 Fig. 97 shows a hydraulic foundry crane of a type intro- duced by Messrs Tannett, Walker, & Co. The large central ram A not only acts the part of a crane post, but has a water pressure always acting upon it by means of the difference of area produced by the reduction of the diameter at its lower part. The total upward pressure acting on this ram is sufficient to nearly balance the total weight of the crane. The two side rams B and c are of a sufficient size to lift the total useful load when brought into use simultaneously. For light loads one only of the rams B and c is used, the other being left open to exhaust. The slewing is operated by hand, the top part of the crane swinging round on the roller path D to reduce friction, while a balance weight E is added which reduces the strains in the crane and also the side friction. This type of crane is very much used in foundries and steel-works. Another type of crane used in steel-works has a central ram only which is large enough to lift the load and balance the weight of the crane as well ; this form is not by any means so economical as the one described above. For heavy foundry work, the crane as shown in Fig. 98 is employed, having all motions operated by hydraulic pressure. The drawing represents a lo-ton crane having a vertical lift of 8 feet, with a maximum rake of 20 feet. The rams are all fitted with multiplying chains and wheels, so that a short stroke of the ram gives the necessary lift to the load, or motion to the travelling carriage or crane, as the case may be. When water is admitted to the cylinder A, the ram is lifted, the motion being transmitted through the chain B, the travel of which is multiplied in the ratio of 4 to i by the pulleys c. This motion is, however, halved by the block D, so that the travel of the weight to be lifted is double that of the ram A 1 . The racking motion is performed by two small rams E F, arranged side by side, and having chains attached to the travelling carriage G. These rams are so arranged that when one is fully out the 184 HYDRAULIC POWER ENGINEERING. WORKSHOP AND FOUNDRY CRANES. I8 5 other is in. On admitting water to the one that is in, the carriage is travelled or racked along, the other ram being drawn in at the same time. The slewing motion is per- Fig. 99. formed by two rams H, placed at the back of the crane post, and similarly arranged to the rams E F, but much larger in diameter. These rams travel with the crane and act on a fixed wheel i secured to the floor plate. All the valves are 1 86 HYDRAULIC POWER ENGINEERING. placed on the side of the crane post, and are operated by an attendant from the foot-plate K. The dead weight of the crane and load is supported by live rollers. Other types of shop cranes are simply modifications of those described, arranged to suit special requirements. In auxiliary lifting appliances, the handy tool, shown at Fig. 99, is useful for light work, such as lifting weights into and out of lathes or other machines. The ram A is supported on^ rollers running on channel irons B, which may form the jib of a Fig. 100. crane, or may be fixed over the machine to be served. The water is fed in through the walking pipe c, having swivel connections, the valves being placed near the machine to be served, and handy to the workman. The ram and cylinder are sometimes placed in a horizontal position. This form of lifter is very useful in connection with riveting machines, being used either to support a portable riveter, or the work to be riveted by a fixed riveter. The form shown in Fig. TOO is intended to be supported from a crane, and carries its own valves, the water being fed WORKSHOP AND FOUNDRY CRANES. to the valves by a spiral pipe. By the use of one of these the work can be much more quickly and accurately adjusted for riveting than if the large crane is to be operated each time. Fig. 10 1 shows a form of direct puller without any chain multiplying gear. The principle of water acting upon a ram or piston is so definite and constant, that it has been applied most ingeniously by Mr Duckham to suspended weighing machines. The application is one that has special advantages for crane or dock work, seeing that the amount of rough usage generally extended to such appli- ances is quite sufficient to damage any spring, and to damage any lever or elaborate mechanism. The attention given to this class of machinery is such that the gauges or standards are absolutely accurate. We illustrate the machine in section in Fig. 102. The construction of the machine we will now describe in detail. The cylinder is bored out perfectly true and lapped with emery to a fine dead polish, thus ensuring an absolutely smooth surface ; the piston rod B, with its plates and leathers, is then fitted. A is the hanging strap, B the piston rod, D the cylinder, c the space filled by the liquid. The indicator gauge screws into the Fig. 101. cylinder, and a filling plug is also inserted in the cylinder, so that it may be filled with the liquid when desired. Oil is generally employed, although in cold climates glycerine is sometimes used. Leakage will not affect the correctness of the indicator upon the gauge unless the i88 HYDRAULIC POWER ENGINEERING. piston actually comes into contact with the bottom of the cylinder, when it will, of course, cease to indicate until Fig. i 02. filled. Re-filling is usually necessary about once a month when the machine is in constant use. WORKSHOP AND FOUNDRY CRANES. 189 When a load is suspended from the piston rod of the machine a pressure is communicated to the liquid, which pressure is then transmitted to the indicating gauge for registration on the dial. The gauge is of the ordinary Bourdon type, having an elastic steel tube of a flattened form of transverse section at one end, and bent to present the figure of a circular arc. The effect of the pressure is to flatten the curvature of the tube and to cause the free end to move with an oscillatory motion ; the free end of the tube has connected to it a rod which gives motion to a rack gearing into a pinion working the hand which indicates the pressure. These suspended hydraulic weighing machines are now used for dead weights requiring indication up to within 20 Ibs., such for example as for weighing boilers, heavy goods, and large packages, where they have been found to be invaluable. CHAPTER XL WAREHOUSE AND DOCK CRANES. THE importance of this branch of hydraulic machinery will be appreciated when we state that it was to the wharf crane that Lord Armstrong at first applied the hydraulic principle, the pressure being obtained from an elevated tank. The elevated tank, however, soon had to give way to the dead- weight accumulator. The success of the early Armstrong cranes was such, both from satisfactory working and saving in cost, that the system rapidly spread, until to-day it is almost universally employed for wharf purposes. In some of the original designs internal packing was used in order to provide two powers to the crane ; this practice has now been abandoned, and all packing is external wher- ever possible. Fig. 103 shows a multiplying hydraulic jigger. This very useful and most frequently employed appliance has the advantage that it can be placed in any convenient position either inside or outside of a building, working vertically or horizontally, and the rope or chain can be led off to raise a cage or for use with a crane jib. A ram A works in the cylinder B, and has a set of pulleys attached to its head, a similar set being secured to the base of the cylinder. The lifting rope or chain is anchored to the cylinder^ and passes alternately over the pulleys attached to the ram head and the cylinder base, and finally away to the load, thus multi- plying the stroke of the ram. In the illustration the stroke of the ram is 5 feet, which is multiplied 8 times, giving a lift of 40 feet, while the net load lifted after allowing for friction is i ton, If the ram is placed horizontally a slightly WAREHOUSE AND DOCK CRANES. 191 larger allowance for friction must be made. Guide rods c are pro- vided to direct the ram A in its outward course, also to act as a stop when the ram has made its full stroke. The valve D is automatically closed at the ends of the stroke by the tappet rod E. As the loads to be lifted vary greatly, it is often desirable to have more than one power, and so save pressure water. There are two good ways of effecting this, which we will describe. By the first method the cylinder is made larger in bore than the diameter of the ram to lift light loads, and a second ram is used, made in the form of a tube, and carrying a stuffing box through which the smaller ram works. This tubular ram has no base, so that the water has access to both rams. The outer ram works in a stuffing box on the cylinder in the usual way. Now if both rams be left free to move when the water is applied, the lifting effort will be that due to the combined area of the two rams, or in other words, to the area of a circle having a diameter the same as the ram working through the outer stuffing box. This constitutes the higher power. For lifting light loads the tubular ram is secured in its lower or in -position by a pair of claws which are passed over its upper 192 HYDRAULIC POWER ENGINEERING. edge, so that the water pressure is only free to operate the smaller ram. By the second method three equal-sized rams working in three cylinders placed side by side are all attached to one common head carrying the rope pulleys. By passing pressure water to all three rams, the maximum load is lifted, Fig. 104. whereas if the central ram be opened to exhaust the remain- ing two will lift two-thirds of the maximum load. For very light loads the central ram only is used, the other two being open to exhaust. Fig. 104 is an illustration of a crane suitable for use in railway goods sheds, and for general loading and unloading WAREHOUSE AND DOCK CRANES. 193 purposes. The lifting is performed by a multiple jigger of the type already described, while the slewing is operated by two small rams placed under the floor, which alternately pull a chain which is anchored to a pulley upon the pillar. The valve levers are placed at the back of the crane. Another very common type of warehouse crane is the wall crane used for loading and unloading ships. These cranes are fitted with long jibs having a derricking motion operated by a hydraulic ram, also a slewing motion of 180, so that one of these cranes can serve a wide frontage of the warehouse. It is often convenient to employ a travelling wharf crane, such as shown in Fig. 105, which is of the bridge type, having an opening large enough for a railway truck to pass through. The pressure water is supplied from stand pipes or hydrants by walking pipes. The arrangement will be readily understood from an inspection of the drawing. All valves are contained in the cabin. In another type of travelling wharf crane the base is made short without the bridge, but in all other respects the design is similar to the one illustrated in Fig. 105. These travelling cranes should always be provided with rail clips to grip the rails, and so steady the crane when lifting heavy loads. Screw blocks are also provided on heavy cranes to relieve the axles of the load. Fig. 1 06 illustrates a large dock crane capable of lifting 160 tons through a height of 50 feet, with a direct puller of the type already shown in Fig. 101. For lifting lighter loads of 35 tons a 3 fall chain block is used, operated by a hydraulic motor or ram and cylinder. The chain passes between pocketed or pitched chain rollers on the motor, and is then deposited in a well. The slewing is performed by a hydraulic motor, which drives a vertical shaft carrying a pinion wheel gearing into a large circular rack. When it is intended to use the chain hoist the large hydraulic cylinder is drawn into an in- clined position by a chain attached to a hydraulic capstan. N 194 HYDRAULIC POWER ENGINEERING. The valve of the large cylinder is operated by a man stand- ing on the elevated platform ; all the other movements are operated from the cabin. The pressure water is supplied from a plant of machinery separated from the crane. Fig. 105. We will close our remarks on cranes with a caution respecting shock due to the too sudden closing of valves. If a load is being raised or lowered it has velocity, and there- fore kinetic energy ; now this energy must be absorbed in WAREHOUSE AND DOCK CRANES. 195 doing work before the load can be brought to rest. The only means we have at our disposal is to close the valve, and so cause a rise of pressure in the hydraulic cylinder. As I I I I Fig. 106. water is only very slightly compressible, the load must be almost at rest by the time the valve is closed if there is no relief valve. A knowledge ~of the laws of moving bodies 196 HYDRAULIC POWER ENGINEERING. tells us that the less time taken to arrest motion the greater is the force or pressure required, so that in reducing the time by closing the valve quickly we greatly increase the water pressure, and a cylinder may thus be broken. By inserting a shock valve either opening to the accumulator pressure or controlled by a spring, we ensure that the pressure in the cylinder can never rise above some fixed amount. CHAPTER XII. HYDRAULIC ACCUMULATORS. HYDRAULIC power is generally employed in an intermittent manner, and when the pressure is produced by mechanical means, the demand upon the pumping machinery is fre- quently very great, while at other times it may not be required at all for some period. It is thus evident that if the water were to be used direct from the pumps, they would have to be of sufficient capacity to meet the utmost demand, and to be capable of giving the maximum quantity required at all times and periods ; so that, in fact, an im- mense waste of energy would result, owing to the diminished conditions requiring a diminished supply from the pumps. Thus, supposing for example that a lift and a press are to be supplied with hydraulic pressure by means of a pumping engine, and that the lift requires 100 gallons and the press 60 gallons per minute, a pump must be employed capable of meeting this double demand, and must supply 160 gallons of water per minute. But the lift will not require the water more than once in every five minutes, while the press will require to be supplied once only in every ten minutes, when working at its greatest possible speed. This united demand, then, requires in one minute out of every ten that 160 gallons of water at full pressure shall be supplied with promptitude and certainty ; but for nine minutes out of every ten this amount would be considerably in excess of the actual needs, seeing that during every five minutes an absolute cessation of delivery to the lift and the press is thus secured for a period of four minutes. The average amount of water that could be supplied, provided means 198 HYDRAULIC POWER ENGINEERING. were at hand for storing up the quantity ready for the full demand, we can determine very easily. During every ten minutes the lift will have made two strokes, and in so doing will have consumed each time 100 gallons of water. In the same time the press will have required 60 gallons of water. Thus 260 gallons of water will be required in that time, so that, if the pumps can be allowed to run constantly, they can be set to work with a delivery of 26 gallons per minute theoretically. But to provide for leaks or waste we require, say, 25 per cent, above this amount, and thus supply 32 J gallons per minute for the duty named. The simplest way of storing up this water is to erect a tank at a height sufficient to give the required pressure by the weight or head of the water column alone. This arrange- ment is frequently and generally adopted fcr hydraulic lifts in warehouses, hotels, and lofty buildings. The water used upon such premises for this purpose is usually pumped up over and over again, so that a large amount of water is not required, as the water escaping from the lifts discharges into one common tank, from which the pump draws it again. As soon as the water rises to its determined height within the tank, a ball or other valve closes the delivery pipe, and the pumps stop ; and when the water level falls, they again start automatically. With this kind of demand it is absolutely essential that the pumps should start off without any dead centre to be overcome or met, and it is found that no pump will maintain this supply, stopping and starting even after standing for a length of time, so well and so effectually as the Worthington. The advantage of employing a tank for such work as that of supplying a lift is obvious from the fact that water may be pumped up in the daytime, ready for any demand which may be made during the night, while the pumps are themselves not at work. When pressures such, for instance, as 700 Ibs. to the inch are employed, it becomes quite impracticable to adopt a tank or a water tower, seeing that a column to give that pressure HYDRAULIC ACCUMULATORS. 199 would need to be 1,610 feet high, and pressures as great as 3 tons to the inch of course could not be provided for Fig. 107. at all in this direction. In such cases accumulators are employed, and assume generally the form of a vertical cylinder, fixed at one end, as illustrated in Fig. 107, and 200 HYDRAULIC POWER ENGINEERING, Fig. 1 08. HYDRAULIC ACCUMULATORS. 2OI free at the other, having a ram or plunger working through a stuffing box and gland, or through a gland and leather cup packing, as indicated in Fig. 108. The hempen packing is the best, owing to its being more easily renewed, but great friction is often induced by such glands being too tightly screwed down. The ram or plunger carries a load, which, in the example illustrated, is made up of cast-iron weights of circular form, which are suspended from the head of the ram cap by means of long bolts passing through them. Instead of cast-iron weights, where space is not so valuable, a tank or vessel, as shown in Fig. 109, is carried by the bolts passing down from the ram cap, either in a truly vertical form, or inclined so as to obtain a more central or distributed support for the load. Within the tank all kinds of material in loose form, such as slag, stones, bricks, etc., are thrown to make up the amount necessary to give the required pressure upon the ram, in order that it may store up the work that the pumps are doing. The accumulator should be placed as near to the pumps as possible; and if the system of pipes supplied is very extensive, it is often desirable to place another accumulator in some position where it may be of most service in taking up quickly any sudden demand that may be made upon the pipes. The load of the accumulator is made to strike against a stop when quite up, so that as soon as it is lifted to the full height the water cannot escape from the pumps, and they arc compelled to stop until the reduction of the pressure by the draught of water permits them to start again. "1'he weights are sometimes arranged to act upon a rod which has a collar attached at any desired point, so that when the weights or the tappet oar strikes the collar the valve is closed, the steam supply shut off from the pump, or the belt driving the pumps is thrown on to the loose pulley. When the weights fall away from the collar by reason of the draught of water from the accumulator, the rod controlling the valve or the belt also falls by its own weight, 202 HYDRAULIC POWER ENGINEERING. HYDRAULIC ACCUMULATORS. 203 or under the influence of an added weight. Thus so long as the accumulator ram is not up to its full stroke the pump will continue to supply water, and will stop when the full stroke is reached. When the pressure is very slight, and only a small quantity of water is required, a plain ram, as shown in Fig. 107, would not be suitable, on account of the small diameter that would be required. Again, when only a small quantity of water under high pressure is required, a small ram, heavily loaded, might not be possible. In these cases a differential accumulator, as shown at Fig. 108, is employed. These accumulators are used with great success by Mr Tweddell in connection with his hydraulic riveting machines. The ram in the ordinary accumulator (Fig. 107) is free to rise in the cylinder, and carries with it the weight. The cylinder rests in the bottom or base plate, which is securely bolted to the foundations. There is only one gland, and that at the top end of the cylinder. Assuming the ram to be 6J inches diameter, the area of which is 38.18 inches, and the pressure upon the water to be 700 Ibs. per square inch, then the load, together with the weight of the ram, must exceed 33.18x700 = 23,226 Ibs.; whereas, with the differential accumulator, as illustrated in Fig. 108, the same load of 10 tons 7^ cwts. is acting upon an annular area obtained from the difference of the two diameters, viz., 7^ and 6j inches. Thus 7^ in. diameter = 44. 17 in. area, and Net area, say= u.o in. Pressure per square inch = *-- - =2111 Ibs. Similarly, if only a light pressure of 700 Ibs. per square inch is required from the differential accumulator, then the load must include the weight of the moving cylinder, which 204 HYDRAULIC POWER ENGINEERING. Fig. no. HYDRAULIC ACCUMULATORS. 2O5 has two stuffing glands, one over each part of the ram, as indicated. The weight then upon the column or ring of water within the cylinder will be 700x11 = 7,700 Ibs., as against 23,226 Ibs. in the simple accumulator. The cylinder of the differential accumulator in Fig. 108 is in reality -the load plate in addition to the water cylinder. Chocks of timber are provided for the weight to rest upon when right down and not in use. Fig. 1 1.0 illustrates a fixed cylinder type of differential accumulator, the moving ram working through two packed glands, and a pit being formed beneath the cylinder for the ram end to work within. Spring-loaded accumulators have been adopted in some cases, but their range is too narrow to require our giving any attention to their construction. In hydraulic installations it is frequently desirable to pro- duce a very heavy pressure beyond the ordinary working pressure of the power mains, or beyond the working pressure of the machines, such increased pressure being to give a final squeeze in connection with pressing operations or in connection with riveting plants. A convenient manner of producing this increased pressure is by means of an intensifier which, in its simplest form, is arranged as a piston working within a cylinder, the piston rod passing through a gland-packed cover, and working in a smaller cylinder carried above the main cylinder. The water from the main is admitted underneath the piston in the large cylinder, and the whole pressure upon it is trans- mitted by the piston rod or plunger on to the water within the small cylinder, the difference in area of the main piston and the piston rod or plunger giving the difference in pressure between the supply main in the lower cylinder, and the intensified main delivery from the upper cylinder. After the water has been withdrawn from the intensifier cylinder, and used in giving the final pressure, the main cylinder valve is opened to the exhaust, and the water from the intensifier main connection is returned into TT-NTTVERSITY 206 HYDRAULIC POWER ENGINEERING. the upper cylinder, forcing downwards the main piston in the lower cylinder. Fig. in illustrates an intensifier for use with a water pressure of 750 Ibs., the water from the mains enter- ing the lower cylinder, and forcing upwards the hollow ram work- ing upon the upper fixed hollow plunger. The intensified pres- sure from within the hollow ram and the hollow fixed plunger guide is delivered through the connec- tion shown at the upper end of the fixed ram, while the supply main connec- tion is shown near the base block of the outer cylinder. The ratio of areas of the main ram and the hollow fixed ram or plunger gives the degree of increase of pressure produced. The use of an in- tensifier of this type in London, where HYDRAULIC ACCUMULATORS. 2O? the main ram was 15 J inches diameter, and the fixed ram 6 inches diameter with a stroke of 13 feet, in a manu- factory for making lead pipes, displaced steam of about 15 h.p., and the cost from the public supply mains com- pared favourably with the old system, notwithstanding the fact that steam power was still in use for other purposes in the same manufactory. PART VL HYDRAULIC PRESSES. O CHAPTER XIII. PRESSES FOR BALING AND OTHER PURPOSES. ALTHOUGH the principle of this class of machinery was first stated by Pascal, it was some - one hundred and fifty years later ere Bramah usefully applied it to the construction of a press. Pascal's statement has been given in full in Chapter I., and amounts to saying that the pressure on a piston is directly proportional to its area. Bramah's closed vessel consisted of a pipe having attached to one end a pump barrel, which formed the smaller cylinder, and to the other end a large cylinder containing a ram, and having a cup leather packing, then for the first time used. The large cylinder had four tension bars attached to it which supported a head or table, and the ram carried a similar table or platten. On placing articles on the platten, and operating the pump, a multiplied pressure was given to the article placed on the platten. The modern baling press is a repetition of Bramah's apparatus on an enlarged scale. The very general use of the hydraulic press, in one form or another, warrants special attention being given to the construction and details of the parts required for particular purposes. Presses are employed for compressing fibrous material, as cotton, wool, esparto grass, peat moss, etc., into small bulk for shipment ; for extracting oil and essences from seeds or roots, for embossing paper and printing lino- leum, also for sheet metal working and forging operations. Baling presses are generally provided with a wood or iron box mounted on wheels and having a loose bottom. The 212 HYDRAULIC POWER ENGINEERING. material is packed tight by hand in this box, which is then placed in the press, and the ram pumped out, forcing the loose bottom upwards, and compressing the material. For the greater part of the run out of the ram but little pressure is required, as the material offers only a slight resistance, but after the ram has run out about four-fifths of the height of the box, the pressure rapidly increases owing to the great resistance of the material to further compression. An inspection of Table X., which gives the pressures in tons per square foot of platten or bottom of baling box to bale cotton, wool, hay, and esparto grass to a given weight per cubic foot, reveals the rapid increase of resistance to compression of these materials after the ram has run out four-fifths of the box. TABLE X. PRESSES FOR BALING : PRESSURE IN TONS PER SQ. FT. OF FLATTEN TO BALE MATERIAL TO THE WEIGHTS GIVEN. Cotton. Wool, Slightly Greasy. Hay. Esparto Grass. Weight in Pounds per Cubic Foot. > >> t _> >. | .!; 3 J5 3 \ .HI * *w 5 f ll I tffi Ptfi PH f*Q PH P^Q PH 80 20 35 18.82 250 ... 70 7-5 1 80 16.47 I4O ... 60 15 TOO 14.11 70 12 60 50 12.5 50 11.76 35 IO 31 10 80 40 10 25 9.41 15 8 4 8 30.3 30 7-5 IO 7.05 6 6 5 6 2O 5 3-5 4-7 2.25 4 J-5 4 2.25 15 3-75 1.8 3-5 1-15 3 .67 3 9 10 2-5 i.i 2.37 .6 2 3 2 3 Weight in Pounds per Cubic Foot, 4 4-25 5 5 Hand-packed. The baling box should be ij inches less in length, breadth, and height than the size of bale required. The PRESSES FOR BALING, ETC. 213 pressures in the Table are for the compression only, and an allowance for the friction of the material against the sides of the baling box must be added. For bales of 40 Ibs. per cubic foot and under add 25 per cent, to the above pressures, and for heavier bales add 40 per cent. Large baling presses are usually supplied with hydraulic pressure pumps driven by steam power, and, as the available power is constant, while the work to be performed varies greatly, many arrangements have been tried for saving time, although the one usually adopted consists of a battery of pumps arranged in groups. The pumps are all set to work during the earlier part of the stroke, thus driving out the ram at a rapid rate. When the pressure rises, so that the work done by the pumps is the maximum available from the steam plant, one group of pumps is automatically tripped or put out of action in a manner to be described in Chapter XVI. The remaining pumps continue to work until the further rise of pressure causes the power to reach the maxi- mum, when another group of pumps is tripped. This tripping is continued until the last group of pumps only remain, and these are so proportioned that they trip when the bale is of the required density. By properly proportion- ing the pumps the ram can be driven out in the shortest space of time possible for any number of pump plungers and power available. We will illustrate this fact by first con- sidering the case where only two pump plungers are used. In the case of a pump having two or any other number of plungers, the smallest plunger is fixed in size by causing it to absorb the maximum power available when on the point of tripping. The remaining plunger may be given any size, and must be arranged to trip out when such a pressure is reached that the two plungers working together absorb the maximum power available. There is, however, a size for this larger plunger, which will cause the ram to travel out in the shortest time. As the equations to the curves of pressures for the different materials are unknown, it is im- 214 HYDRAULIC POWER ENGINEERING. possible to give an equation for finding the size of the larger plunger; the graphic method in Fig. 112, however, gives very close approximations to the truth. Fig. 112 represents the curve of pressures for baling hay to a weight of 50 Ibs. per cubic foot, or to a bulk of one-tenth that of hand-packed hay. A B represents the length of the baling box filled with Fig. 112. hay, A c the stroke of the ram. and c B the final depth of the bale of hay. The curve A M F j D is the curve of pres- sures per square inch of pumps drawn out to a scale making c D equal to A c. This curve is ascertainable from Table X. Complete the square A c D E, and join E c, cutting the curve in F, and draw the vertical F G, then F G represents PRESSES FOR BALING, ETC. 21$ the pressure per square inch at which the larger pump must trip. This pressure being known, the combined area of the two pump plungers can be fixed such that the total available power is absorbed at this pressure. The size of the smaller plunger being already fixed, the larger is ascertained by subtraction. If three pump plungers are to be used, the pressures at which the two larger must trip can be found by drawing the diagonals L RI, H j so that the area of the square A c D E is divided into three equal parts, or from which A L may be found. The diagonals L M, H j having been drawn, the verticals M N, j K give the pressures at which the pumps must trip. The sizes of the plungers are now ascertained by finding the combined area of the small and medium plungers, at the pressure j K, to absorb the maximum available power, from which area the size of the medium plunger is found, as before, by subtraction. In the same way the combined area of the three plungers is found for the pressure M N, and the size of the largest ascertained by subtracting the combined area of the other two. An example will render the process more clear. Hay is to be baled to a weight of 50 Ibs. per cubic foot, and the press is to be worked with a maximum pressure of 2 tons per square inch. The maximum available power is 3! horse-power. Referring to Table X., the weight of hand- packed hay is 5 Ibs. per cubic foot. When compressed to 50 Ibs. per foot, the space occupied will be one-tenth, or the ram must travel nine-tenths up the baling box. A B and A c can now be laid down, making c B one-tenth of A B. Construct the square A c D E, and draw the curve of pres- sures, making c D represent 2 tons. Draw the diagonal E c, 2l6 HYDRAULIC TOWER ENGINEERING. and scale off F G, which in this case is .217 ton The sizes of the plungers may now be settled. 3^ h.p. = 33000 x 3.75 = 123,750 foot-lbs. per minute. Efficiency of pumps, say .66. Energy available = 123750 x .66 = 82500 foot-lbs. per minute. The velocity of the plungers may be anything up to 50 feet per minute. In the case under consideration the small plunger may be made i inch diameter, and its travel in feet per minute will then be 82^00 -=23.16 feet. .7854 x 2 x 2240 A i -inch plunger working against a pressure of 2 tons per square inch requires to travel through 23.16 feet to develop 82,500 foot-pounds of energy. As the plungers are only single acting, the actual velocity of the plunger becomes 23.16x2 = 46.32 feet per minute, which is under 50 feet velocity. The stroke and consequent number of revolutions may be settled last. The size of the larger plunger may now be ascertained. Let A be the area in inches of the larger plunger (.7854 + A).2i7 x 2240 x 23.16 = 82500 foot-lbs. A = 6. 68 square inches. 3 inches diameter = 7.07 inches area. Therefore we may use a 3 inches diameter plunger tripping at a pressure of 450 Ibs. per square inch, and a i inch diameter plunger tripping at a pressure of 2 tons. By adopting a stroke of 4 inches, the number of revolu- tions per minute of pump shaft is 23.16 x 3 = 70.08 revolutions. The large ram of the press must be proportioned to give a pressure of 31 tons per square foot of platten, with an addition of 40 per cent, to overcome friction of baling box, PRESSES FOR BALING, ETC. 2 17 and 2 tons for stuffing box friction, making a total of 45 tons per square foot of platten. If three plungers had been desired, the smallest would still be the same size i inch diameter. The two larger ones are found by drawing the two lines L M, H j in Fig. 112, as directed, and scaling M N, j K. JK =.48 tons per square inch. = .o6 2 The area A of the middle plunger is found as before, but for a pressure of .48 tons. (.7854 + A). 48 x 2240 x 23.16 = 82500. A = 2.53 square inches. ij inches diameter = 2.40 inches area. The area B of the large plunger may now be found (B + .7854 -f- 2. 40). 062 x 2240 x 23.16 = 82500. 6 = 22.47 square inches. 5^ inches diameter = 21.64 inches area. The plungers to be used are 5 J inches diameter tripping at 132 Ibs. per square inch, if inches diameter tripping at 1,085 I DS - P er square inch, and i inch diameter tripping at 2 tons per square inch. If in designing the 5 J-inch plunger gives trouble and re- quires a wider spacing of the cranks than is necessary for the strength of the crankshaft, the stroke may be increased to 6 inches, and the diameters of plungers reduced accordingly. 4 inches increased to 6 inches. i in. diam. =.7854 area reduced = .785 4 x = .52 in. area = } in. diam. if ,, =2.40 =2.40 xf=i.6 ,, = 4 Si ,, --=21.64 ,, = 21.64x3 = 14.42 = 4| Fig. 113 represents the usual form of hydraulic press, having a cylinder A of cast iron or steel, the latter being much in request for presses for export, as the weight is then only 2l8 HYDRAULIC POWER ENGINEERING. Fig. 113. PRESSES FOR BALING, ETC. 219 about one-third. The cylinder has a U leather packing B and ram c, and rests on the faced edge of the base plate D. The head E of the press is attached to the base D by bolts, or pillars F, usually four in number. The ram carries a platten G, on which the article to be pressed rests. Water is admitted to the cylinder at H. Instead of the pillars F being made, as shown, with a nut at each end, they are sometimes made with two forged collars at each end, and the bosses of the head and base are split to receive them, and fitted with caps bolted on. The platten is guided by Fig. 114. the bars F, and has its corners curved to fit the bars, or sometimes slipper guides are bolted to the platten to increase the rubbing surface. Suitable thicknesses for the cast-iron rams are given in the following table : Diam. of Ram in Inches. 6 8 10 12 H 16 18 2O Thickness of Ram. in Inches. ii M if 2 2| 2j 2| 2i The pillar F is shown in detail in Fig. 114, and the sizes are given in Table XL (next page). 22O HYDRAULIC POWER ENGINEERING. TABLE XL SIZES OF WROUGIIT-IRON BARS FOR PRESSES. 4 Bars to a Press. J A Press For length of Test Load. i' to 4' 4 to 7 7 to Jo 10 to 13 C. C. D. E. F. G. H. Tons. In. In. In. In. In. In. In. In. In. In. In. 10 Ii I* If ii If 2^ 2 1 :i 4 Ii 2O I* H !? Ti *4 It 2| 2 :s 5 Ii 30 If i| If i :t l ~5 If 2i 2A :s i| 40 H if 2 2| I.T i| 2| 2| i ^ i| 60 I| 2 2* 2* 1 1 2 31 ,VlV s i ii 83 2,i 2| 2| 2? 2* 2i 3i 3VV ^ 2i 100 2f 2* 2| 3 2| 2^ j! ^ > 2| ISO 2| 3 3i 34 2^ 2\ 31 4A i I 2* 200 3* 3i 3i 3* 3i 31 4 4l i I 3i 300 4 4 4 4i 4 4i 5^ 6 i 1 4 Fig. 115 is a plan of the usual form of press head. The stresses occurring in the head vary according to the manner in which the load is distributed, and are worthy of investi- gation. In any manner of loading in which the centre of pressure of the load coincides with the centre of the head, or at the intersection of G H, N O, the load is equally distributed to the four pillars at A B C D, and if \V represents the total load or pressure on the head, each pillar carries a load of W . Whatever share of the load is carried by the ribs EF, 4 GH, IK, and LM, NO, PQ is transmitted to the four side ribs AD, BC, and AB, CD, which in turn transmit the load to the pillars. As the four ribs AD, BC, AB, CD, each carry an equal load, that load is evidently . 4 PRESSES FOR BALING, ETC. 221 Four typical methods of loading have been selected for investigation, and any others may be considered as similar to one or other of these with sufficient accuracy. R i i 1 ____ J ___ 1 M Q Fig. 115- These four methods of loading are : - (i.) Load distributed over the whole press head within the centre lines A B C D. (2.) Distributed over the area bounded by the line R. (3-) ., ., S. (4-) ,, T. 222 HYDRAULIC POWER ENGINEERING. In all these cases the load W may be divided into two W parts ; one of which is supported by the ribs running in one direction, as AB, EF, GH, IK, DC; and the other by the ribs at right angles to these, as AD, LM, NO, PQ, BC. w In (i) the load carried by AB, EF, GH, IK, DC is divided up as follows : W W W W 4 _W = W f6 + ~8 8" ' 76 ~ 7' and a similar load is carried by the remaining bars, so that W AD carries a load of . 16 AD also carries half the loads of EF, GH, IK, so that the total load on AD is W W W W W + __ + + = _ as above stated. 16 16 ID 16 4 The bending moments may now be expressed : for AD -, 128 for EF, GH, or IK- W . 64 The load on AD is not evenly distributed. W In (2) the load is carried by EF, GH, IK as follows : W W W = W ~6 ~6 ~6~~^' Half of these loads are carried by AD, or W W W = W 12 12 12 4 PRESSES FOR BALING, ETC. 223 The bending moments in this case are : for AD = WL 24 forEF, GH, or IK= . 48 In (3) the load is carried by EF, GH, IK, as follows : W , W W = W 8482' Half of these are carried by AD, or w w w = w 16 "8" i6~~^' The bending moments are : for AD = 64 W T for EFor IK= , 64 32 In (4) the load is carried by GH W = \V 2 2 Half of this is carried by AD 4 4 The bending moments are : for AD = , 16 -, 8 for EForIK = 224 HYDRAULIC POWER ENGINEERING. Fig. 1 1 6. PRESSES FOR BALING, ETC. 225 The section of metal required may now be determined. The flat plate of metal forming the face of the head is made of the same thickness of metal as the ribs, and may be included in taking out the sizes. By first neglecting the flat plate each rib may be deter- mined as a rectangular section by equating its bending moment to the moment of resistance of a rectangle. Thus for AD in (i) 128 6 where b is the width of the rib, h the height, and /the stress to which the metal is to be subjected. If L is in feet, b and h must also be in feet, and if w is in tons, / must be in tons. By selecting values for b and f and solving this equation, the value of h can be found ; it is usual to fix values for b and / and if // is unsuited, b must be varied and another value found for //. These values being settled, the correct height // L of the head can be ascertained as follows : Let r be the distance between the ribs. To avoid difficulties in casting it is usual to find the dimensions of the strongest rib, and make the others of the same dimensions. -The formulae have been worked out for square heads with three intermediate ribs. They are, however, applicable to any rectangular head with not less than three intermediate ribs, and having the load distributed over a rectangle having the same ratio of sides as the head. Fig. 116 represents a baling press and box complete. The cylinder A, containing the ram carrying the platten B, is carried by the base c, which in turn is connected to the head D by the bars E. Guide rails F are attached to the bars E and supported at G. The baling box H runs on grooved P 226 HYDRAULIC POWER ENGINEERING. Fig. 117. PRESSES FOR BALING, ETC. 22; wheels resting on the rails F. The bottom of the baling box consists of a piece of grooved hardwood resting on a ledge or fillet. The cotton or other material to be baled is packed in the box H by hand, and the box is then drawn into the press by revolving the handle i which causes the chain K attached to the baling box H to travel, and so move the box H. The front of the box H is cut away at the top to clear the hard- wood block M on the press-head. When the box is central over the ram, the water is pumped into the cylinder A, and the platten B passed up inside the box H carry- ing the hardwood bottom with it. When the baling operation is completed, the hinged doors N and o of the baling box are opened, and the box H withdrawn by turning the handle i. The upper part of the baling box H has three of its sides hinging out- wards to allow of the expansion of the bale on the pressure being released. The box H having been re- moved from the press, the doors N and o are closed and refilling commenced. The bale in the press is at the same time hooped with iron bands which are passed 1 I ! I I 1 i! h 1 T _., K v / / f i i P rii' 1 l -L< 1--- ---.. - - , _Lr ii"*i fl \ . i u F i I '"- r _-_J L V Fig. 1 1 8. through the slots in the hardwood blocks, and secured round the bale by riveting or other suitable means. The ram is now lowered into the cylinder, and the bale removed. 228 HYDRAULIC POWER ENGINEERING. Fig. 117 represents a dumping press which is made in exactly the same way as the hydraulic presses already noticed,, but in place of the baling box it is supplied with steel bars a, a, a, of strong T section. The bars are usually hinged at the base, and fitted with a draw-pin at the head of the press. The material is lightly baled in up-country districts in screw- power presses, and when brought to the quays is pressed or dumped to the requisite size for shipment in a press of this description. Fig. 118 represents one form of hydraulic oil-press suit- able for extracting oils or essences from seed and roots. The press is precisely similar to a baling press in the main features, but has a series of hanging plates or platforms equally spaced as shown. The seeds or roots are placed in flat canvas or horse-hair bags, which are placed on the plates, and the press is then operated. The oil or essence escaping trickles off the edges of the plates, and over the down-turned edge of the platten into the flat tank A, where it is run off by the pipe B into suitable vessels. CHAPTER XIV. SHEET METAL WORKING AND FORGING MACHINERY. IT was about the year 1860 that the hydraulic press was first practically used for the forging of ingots for big guns at Messrs Whitworth's. About the same time the English engineer in charge of the Vienna locomotive shops intro- duced a hydraulic press for forming the various details of locomotives and railway stock. The work done was of a varied nature, including forging in closed dies, punching, and drawing out and dumping operations. Needless to say, there was the usual prejudice to the new tools and methods, but their superiority was evident to lead- ing engineers, so that at the present time the hydraulic press is almost solely used for large work, whilst its popularity for small work is rapidly increasing. Beftfre passing to the hydraulic machine tools proper we will notice a small hand-worked punching bear illustrated in Fig. 119. The punch is attached to a ram A fitted with a cup leather, and working in a cylinder B formed in the main frame of the bear. The cylinder is surmounted by a water cistern c containing a pressure pump worked by a hand lever D. When the pump is worked water is forced into the cylinder B, so driving the ram down and forcing the punch through the metal. To raise the punch clear of the work the thumbscrew E is loosened, and the cam F attached to the lever G is operated, thus driving the water back into the cistern c. We will now consider the usual types of forging presses in 230 HYDRAULIC POWER ENGINEERING. use. Fig. 1 20 gives a general idea of the arrangement of a large forging press. The cylinder A, carrying the ram B, is supported by two or four vertical columns c, secured to the base D, which carries the anvil or bottom die. Two cylinders E F are fixed to the press, and are always open to the pres- sure water, so that when the large cylinder A is open to exhaust, the pressure acting on the rams G H drives the ram Fig. 119. B up, thus the press is controlled by one valve only. In many designs of press the drawback cylinders E F are placed the reverse way up, and are secured to the large head cast- ing, being then provided with tension rods to lift the ram B. Arrangement of minor points must, however, be governed by circumstances, as if the press is too lofty it will interfere probably with the passage of overhead travelling cranes. SHEET METAL WORKING AND FORGING. 231 When four columns are used, they are so disposed as to keep the press as narrow as convenient in one direction, so that the tackle for handling the forging may be brought as close as possible to the dies. Various methods are adopted for securing the head to the columns ; in the press shown the head rests on a collar or neck formed on the column, and is secured by a nut. In another method the column has two collars formed near each end, and the head and base castings have bosses bored out and fitted with caps the column is in- serted and the cap bolted on. In some presses provision is made for altering the depth of the gap or space between the ram and anvil, or "daylight," as it is called. This is generally done by placing the cylinder at the bottom, and the top casting is made adjustable by hav- ing the pillars screwed for a considerable length, and provided with two nuts for locking the casting in the required position. jrj g I2a Different firms have at times produced presses varying in design and claiming special advantages. The Davy press has two cylinders placed side by side, and attached to one common cross- head, the crosshead being provided with a long arm pro- jecting upwards from its centre, and having a turned cylin- drical part at its upper end. This cylindrical part works 232 HYDRAULIC POWER ENGINEERING. in a tubular guide placed between the two cylinders, and together with the guides working on the columns forms a triangular support, giving great steadiness to the top die. Another advantage of this form of press is that the pressure on the dies may be considerably off the centre line of the press without causing severe straining. A multiple power press, designed by Messrs Tweddell, Fielding, & Platt, has three equal-sized rams placed side by side below the floor level, the rams all acting on a common crosshead, connected by strong tension bars, which also act as guides to the head of the press carrying the top die ; whilst the bottom die is supported by a base which also carries the three hydraulic cylinders. Three different powers are obtained by this arrangement, according to the number of rams acted upon by the pressure water. This press also has the advantage that the head room is unobstructed, thus allowing a free passage for travelling cranes. For very large forging presses it is not usual to work with an accumulator, the water being supplied direct from a pump into the cylinder, the idle part of the stroke being performed by the pressure of water contained in an overhead tank. The lifting cylinders are frequently operated by a steam accumulator, or by pressure water from an ordinary accu- mulator. By another method the pressure is applied by a direct steam driver, which consists of a large steam cylinder coupled direct to a plunger, which is connected without the interposition of valves to the press cylinder, the steam cylinder being operated by an ordinary slide valve. It is absolutely necessary to use a high pressure in the cylinders- usually 2 to 3 tons per square inch otherwise the machines become very costly and heavy in weight, or the manufacture is rendered impossible. Fig. 121 shows the usual arrangement of a small open-sided or C press, which can be conveniently made for pressures up to about 150 tons. In the illustration a vertical forging ram SHEET METAL WORKING AND FORGING. 233 A is shown, also a horizontal ram B, each supplied with a drawback ram constantly open to the water pressure. Two valve levers are shown, one to each cylinder. Hydraulic push-back cylinders are supplied to each ram, and are always subjected to the pressure water. Machines of this type may be used for all kinds of stamping and punching as well as general forging. Fig. 122 shows a section of the cylinders and ram of a Tweddell punch. The ram A carrying the punch is formed of two circular parts placed eccentric to each other, thus placing the punch well forward and easily visible. The ram A is packed by a U leather, and works in the gun-metal lined cylinder B. The re- turn motion of the ram is effected by the drawback ram or piston c working in the cylinder D, which is always open to the pressure water. A water-saving ap- pliance is added, which is operated by the lever E, and closes the valve when the punch has penetrated the metal. The working of the water-saving appliance will be better understood by an examination of Fig. 123, which illustrates a manhole punch or flanging press. The only difference between this and the last press lies in the fact that the dies are arranged centrally with the ram. The down stroke of the ram causes an oscillation of the lever F, which by means Fig. 121. 234 HYDRAULIC POWER ENGINEERING. of the adjustable tappets or nuts G causes a movement of the hand lever H, which operates the balanced valve I, cutting off the water pressure. The attendant now gives the valve a Fig. 122. further movement, opening it to exhaust, the ram rises, and in doing so oscillates the lever F in the opposite direction, causing the adjustable nuts K to move the hand lever H SHEET METAL WORKING AND FORGING. 235 and valve i back to the central position, ready to be again operated by the attendant to cause the next down stroke. Fig. 124 shows a shearing machine having the water-saving mechanism so arranged that the valve may be worked by either hand or foot power. In this machine the drawback ram is placed behind the large cylinder in the main casting. Fig. 125 illustrates Tweddell's plate-bender, for forming Fig. 123. the shells of large boilers and for similar work. The plate to be bent is fed through the slot A, water pressure is then applied to the cylinder B, causing the die c to advance towards the die D, so bending the plate. The die c is returned, on the cylinder B being opened to exhaust, by the drawback ram E. The plate is now further advanced and another stroke of the die c given. By this means the plate is bent to the final curve at the rate of 2 to 3 feet per 236 HYDRAULIC POWER ENGINEERING. minute. An adjustable stop is provided which prevents the dies coming too close together, and so forming a circle of less radius than is required. The dies are not made to any radius, but the die D has a central rib, while the die c has two ribs a short distance apart. To remove the work the head F is slewed round. A hinged tie-bolt is, however, some- Fig. 124. times provided to connect the die D to the main frame at its upper end. Fig. 126 shows in plan the general arrangement of a tube- drawing machine. A hydraulic cylinder A is provided, having connected to it two long bars B supported on feet. The tube to be drawn is first slightly reduced at one end, and then, having been threaded on to the mandrel, is placed in the SHEET METAL WORKING AND FORGING. 237 machine with its reduced end passing through the die carried in the holder c. The tail end of the mandrel is now attached to the support D, and the reduced end of the tube is gripped by the jaws E carried by the crosshead F, capable of being drawn along by the water pressure acting on the piston G. The stroke being completed, the tube is removed and the crosshead F returned by water acting on the back of the Fig. 125. piston G, the water in front being returned to the accumu- lator. Fig. 127 shows a hydraulic press arranged for putting on and taking off railway rolling stock wheels. The action will be readily understood from the illustration. The wheels to be operated upon having been suitably adjusted between the tension bars A, the ram B is pumped out by the hand pump c, so forcing on or taking off the wheel, 238 HYDRAULIC POWER ENGINEERING. CHAPTER XV. HYDRAULIC RIVETERS. THE very general use of the hydraulic riveter for ship- building, boiler-making, and girder work is undoubtedly due to the efforts of the late Mr R. H. Tweddell and to Messrs Fielding & Platt. Water power is particularly suitable for riveting, in that the machines consume no energy except when actually at work, and being portable in most cases, can be readily carried to any desired position upon a scaffold or within a structure or frame where ordinary machines having rotating power or shafting could not be employed. The system of laying the hydraulic pipes or mains with union branches at positions likely to be suitable for any special tool, or any part of a building yard or dock, provides, with the use of travelling on telescopic joints, an easily controlled and economical method of mechanical riveting. In Fig. 128 is shown in sectional elevation the motive power end of a portable riveter. The water pressure is used to give three distinct move- ments to the operating members. First, in the cylinder formed within the ram B, the ram D being forced out, carry- ing with it the plate-closing die E, also the ram B and rivet- closing die c. Second, in the cylinder A forcing out the riveting die c, thus closing the rivet. Third, the water always at constant pressure on the ram H, within the draw- back cylinder G, carries back or returns the rams B and D when the other cylinders are opened to exhaust. The water from L enters the cylinder within B by means of the sliding 240 HYDRAULIC POWER ENGINEERING. HYDRAULIC RIVETERS. 241 packed joint at the upper end of the ram B, and the passage shown in dotted lines K admits the pressure from the valve which is usually attached adjacent to the passage. Swivel- ling is provided for by the suspension arm M being formed with a boss for the frame stem N to pass through. Fig. 129 illustrates a portable riveter having a hand worm and wheel for swivelling the frame into any position to suit the work. The hanger is made of cast steel, and by means of a flexible pipe the necessary movement is obtained without difficulty. Variable power is sometimes desirable in connection with fixed or portable machines, so as to obtain the best results without necessitating a constant consumption of water when the duty is not a constant one. Fig. 130 illustrates in elevation a double power and plate-closing riveter of 150 Q 2 4 2 HYDRAULIC POWER ENGINEERING. tons power, and having a gap of 8 feet suitable for marine boiler plate riveting. Fig. 131 illustrates in sectional view the motive power end of a plate-closing riveter, having arranged thereon also water- saving rams whereby an economy of about 60 per cent, is obtained. Three valve levers are employed to control the 11 1" 1 ^""' f three valves A u c, being the water-saving valve, the plate- closing valve, and the main ram valve respectively. Water from a tank having a head of about 20 feet supplies the valve A, which is used to advance the plate-closing ram D, which carries the closing tool d. The water-saving and drawback piston ram E is fed by water on both sides of the piston, the difference of area of the full outer against the inner annular HYDRAULIC RIVETERS. 243 244 HYDRAULIC POWER ENGINEERING. end causing the ram E to advance and with it the rams D and F, so that the plate-closing tool d and the cupping die/ are brought close up to the work, the movement being assisted also by the low-pressure or tank water being at the same time taken into the main cylinder H and the plate-closing cylinder K. Pressure water is then admitted into the main cylinder, the effective area being the difference of the areas of the plate-closing ram K and the main cylinder H, some water escaping from the plate-closing to the main cylinder through the common supply pipe to allow the main cylinder H to move relatively to the plate-closing cylinder K. After the pressure has been kept on the rivet a short time, the water from K and H is exhausted back into the tank, the pressure on the annular drawback piston E causing the return stroke on the other or full area end of the piston being opened to the exhaust. Wherever possible the cylinders should be lined with gun- metal or phosphor bronze, the valves being also of the same metal throughout. PART VIL PUMPS. CHAPTER XVI. HAND AND POWER PUMPS. IN examining briefly the ordinary forms of hand and power driven pressure pumps for transmitting water under pressure to presses, accumulators or other hydraulic machines, we pass over entirely the ordinary suction and bucket and plunger or force pumps used for the domestic supply and delivery water into tanks or reservoirs, and glance Fig. 132. instead at the type of hand pressure pump as shown in sectional elevation in Fig. 132. The pressure pump as shown is suitable for working up to pressures of 2 tons per square inch, and is particularly useful for boiler and other testing purposes, the pump A being fitted with a trip lever H for opening the suction valve upon the set pressure being obtained. The plunger u, Fig. 133, is re- ciprocated in the cylinder A of the pump casting, the water 248 HYDRAULIC TOWER ENGINEERING. entering from the cistern or tank to which the pump is secured through the suction valve c protected by a strainer D to fill the cylinder A. The back stroke of the plunger forces the water through the non-return valve F, closing at the same time the suction valve c, and delivering the water through the end branch E of the pump stem to the pipe attached thereto. To release the pressure the stop spindle G is turned, thereby opening the delivery port to an outlet port allowing the water to flow back into the cistern. Fig. 133- The plunger is reciprocated by a hand lever which is placed on the end of the spindle K, thus giving the desired movement to the tumbler or cam arm L, which works in an opening provided in the central portion of the plunger. The passages for the water are drilled out of the solid metal of the casting, and the ends afterwards plugged by screwed and riveted plugs as shown in Fig. 134. The trip or release valve is described in connection with the vertical plunger pump shown in Figs. 136 and 137. The hand HAND AND POWER PUMPS. 249 pressure pump illustrated in Fig. 135 is provided with a ver- tical plunger A, and has the hand lever balanced and pivoted on to the standard or frame B, a trip or relief valve c is arranged upon the pump, and the stop or release valve D is placed horizontally. The passages and valves of the pump are similar to the valves shown in Fig. 133, the plunger also being of the same type, having its packing formed by a leather lace bound tightly round a groove. Pumps driven by belting or gearing for hydraulic purposes Fig- i34- have much in common with the typical hand pump already examined, and Figs. 136 and 137 show in elevation and in detail a very useful type of belt-power pressure pump. The crank shaft is connected direct to the plungers, which are arranged in varying sizes upon the standard for the purpose of giving a quick run up of water at a low pressure for such a duty as a packing press where, as we have before pointed out, a varying pressure is always required during the travel 250 HYDRAULIC POWER ENGINEERING. of the press to suit the density of the material which is being compressed. Trip levers are connected with each pump, and they are so arranged that the pressure produced upon the water by the resistance of the material between the press platten Fig- and head shall cause a small valve B to raise the loaded lever c, and with it the bottom foot lever D, which then raises the suction valve w off its seat, thus causing the power of the pump to be given to the two remaining plungers, which are of smaller area. When the pressure is further increased HAND AND POWER PUMPS. 251 owing to the material being more densely compressed, the second trip lever is caused to move by its valve being urged to overcome the corresponding weighted lever, and thus Fig. 136. another plunger is thrown out of action, leaving the last plunger of a smaller diameter to give the final pressure to produce the maximum load against which it is set by its trip lever. By this arrangement of trip levers any desired pressure 252 HYDRAULIC POWER ENGINEERING. can be produced upon the final plunger while leaving the early movements of the pump to deliver water at a very much lower pressure, thereby economising the power and water and making the pressing operation a quick one. It should be noted that the trip valve which acts against the loaded lever does not allow any water to escape, but simply moves upwards within its bored port, the leather packing on Fig. 137- the end of the valve keeping the pressure tight within the pump passages. The well-known bucket and plunger pump employed for ordinary water-raising purposes, where a continuous flow of water is required from the single up and down motion of one plunger, has its counterpart arrangement for hydraulic power purposes as shown in Fig. 138. In this pump, which is suitable alike for hand or power, the suction valve A is only HAND AND POWER PUMPS. 253 operated at each alternate stroke, and by proportioning the areas of the plunger half the quantity of water drawn in the suction valve A is delivered through the delivery valve u at each stroke. The non-return valve c, which acts as the check valve to the full end of the piston, is forced upon its seat during the in or suction stroke of the piston by the pressure water travelling from the annular or front end of the pump, the valve B being opened for delivery during this period. During the outward stroke of the piston the suction ob, r ** U/J&/sTB/\ A 1 & k^x^//a%ocjf ' Fig. 138. valve A is forced on to its seat, but the check valve c is raised, allowing the full bore of the pump barrel to be dis- charged through it, half of this quantity going to fill up the annular space in front of the piston, while the other half is delivered through the outlet valve B. This counterbalancing of fluid pressure within the pump barrel renders the arrange- ment particularly suitable for all classes of pumping machinery, as no unequal strains are set up during the working of the pump at any speed. CHAPTER XVII. STEAM PUMPS. THE varieties of steam pumps for hydraulic pressure purposes are almost as numerous as the varieties of the ordinary steam engine, although possibly the pumps have more in common than have the engines produced by various makers. Unquestionably the most satisfactory type for general Fig. 139. purposes of a small installation where steam is available is the duplex pump, first introduced and perfected by H. R. Worthington, of America. The Worthington pump, as illus- trated in Fig. 139, has two steam cylinders side by side, the piston rods of each cylinder being continued to act as the pump rods of the two pumps at the opposite end, the pump STEAM PUMPS. 255 castings being connected to the cylinders by distance pieces, as shown. The valve of each steam cylinder is an ordinary slide valve, but the ports are duplicated at each end. No lap or lead is given to the valve, but a small space or slack is given between the nuts and the jaw of the valve. This lost motion permits the valve rod to travel slightly before moving the valve, thus allowing a slight pause in the motion of the piston at the end of each stroke, thereby giving the water valves time to seat smoothly and without violence. The valve of one cylinder is controlled by the piston rod of the other, the motion being transmitted through the vibrating arm pivoted on the distance piece. The moving parts being Fig. 140. always in contact, the blow which arises with tappet con- trolled valves is avoided. When the piston in its motion covers the first port, which is the exhaust, the steam remain- ing in the cylinder is cushioned in front of the piston, thus causing a gradual arrest of its movement. One or other of the slide valves being always open, trfere is no dead point, and the pump is therefore capable of being stopped and started at any time. This property of constant readiness for full duty enables the Worthington or duplex pump to be employed for working direct on to hydraulic lift cylinders or on to an accumulator, the pump following up the motion of the lift on the rise and fall of the accumulator automatically 256 HYDRAULIC POWER ENGINEERING. when the pressure from the pump delivery main is drawn upon. In connection with pumps it is desirable to employ an air chamber on the suction main as ^yell as on the delivery main, in order to make the flow of water continuous and to ensure that the cylinder shall be filled at each stroke. When an air vessel is not possible on the suction side,, it is an advantage to give the water entering the valve a little head by causing a T branch con- nection with the suction pipe and the pump barrel to be made, the water in the T thus standing above the pump barrel. The flow into the suction pipe should not exceed 150 to 200 feet per minute. The speed of the plunger may be from 65 to 150 feet per minute. The pressure pump shown in section in Fig. 140 is a Worthington packed plunger or double-ram pressure pump. Fig. 141. Fig. 142. The barrel is divided, so that each end is an independent single-acting plunger drawing water at the one end, while the opposite plunger is forcing it out at the other end of the divided barrel. A number of independent pressure valves STEAM PUMPS. 257 258 HYDRAULIC POWER ENGINEERING. are employed, easily accessible, and are contained in small chambers for resisting heavy pressures. These pumps work up to 8,000 Ibs. to the square inch. The plungers are connected by means of yokes and outside rods, so that they move together as one plunger and become double acting by the division of the barrel. Fig. 141 shows a sectional view of the pump barrels and their valves, a common suction and delivery branch being alone required for the two inde- pendent double-acting pump barrels. These pumps work best when the plunger speed does not exceed 50 feet per minute. A fly-wheel double-acting pressure pump, having a hori- zontal steam cylinder, as shown in Fig. 142, is often em- ployed for small hydraulic installations. The valves are arranged at the extreme end of the pump, and being imme- diately above each other, admit of easy examination and renewal. A vertical cylinder engine with expansion valve having direct coupled pumps is shown at Fig. 143. In this example the water is drawn in and forced out at right angles to the line of axis of the pump. The valves are very accessible, and the pump plungers are easily packed. This type of engine is in use at the pumping station of the Hydraulic Power Company, of London. STEAM PUMPS. 259 The pumps illustrated in Fig. 144 were made by Messrs Berry for the London County Council, and have two steam cylinders with direct-acting pumps, 2\ inches diameter by 12 inches stroke, the pump plunger rods being connected through the back ends of the cylinders to 9 inches diameter steam pistons. The pumps supply an accumulator, and work at 750 Ibs. per square inch. PART VI1L HYDRAULIC MOTORS. CHAPTER XVIII. TURBINES. BEFORE proceeding to the detailed examination of the various types of turbines, we will examine the action of a stream of water on a curved vane. If a stream of water having a certain velocity ^ meets a stationary curved vane, the path of the stream will be altered, following the curve of the vane and leaving in the direction which the vane would take if continued. Neglecting losses from friction, the velocity c. 2 of the stream will be the same on leaving the vane as on entering, the only change being one of direction. If now a velocity u\ be given to the vane, an inspection of the diagram (Fig. 145) will show that the water may never touch the vane at all ; for when the stream has reached and w^ or ?/. On entering the vane the stream had an absolute velocity of r, and a corresponding store of energy 264 HYDRAULIC POWER ENGINEERING. On leaving the vane the absolute velocity of the water is u and the corresponding energy Now if u is less than c the energy remaining in the water on leaving the vane must be less than the original energy con- tained in the stream, so that neglecting the losses by friction the difference of energy has been imparted to the vane, and is capable of being applied to perform useful work. Fig. 145- The velocity of entry c is generally fixed by circumstances, and the designer has to convert as large a percentage of the energy contained in the stream at disposal into useful work. This is obtained by keeping the velocity u of discharge as low as possible, and thereby increasing the difference between the energy of the entering stream and that of the leaving stream. The velocity u cannot in practice be made O, as the water would not then flow from the vane at all. It will be noticed that no mention has been made of the exact curve a turbine vane should take, and it may be here TURBINES. 265 stated that there is no particular curve to be followed, the only conditions being that the curve of the vane shall flow gradually from the angle of entry to the angle of exit. There are two distinct classes of turbines, namely, Impulse and Reaction. Each of these classes contains several types, having the flow of the water arranged in different directions. These types may be enumerated as below : IMPULSE. REACTION. No Suction Tube. Radial outward flow. ,, inward ,, Axial flow. Pelton wheel. With or without Suction Tube. Radial outward flow. inward Axial flow. In an impulse turbine the action of the stream follows very closely the explanation already given, and our sub- sequent remarks will relate more to precautions to be observed in designing. The water is directed into the vanes of the wheel in the required direction by fixed guide vanes, so arranged in size that the wheel is never allowed to become filled with water or drowned. The outlet is also above water, so that the stream in passing through the turbine is at all times under atmospheric pressure. Fig. 146 shows a sectional elevation of a Girard impulse turbine, and Fig. 147 shows an end elevation partly in section of the same wheel. The water enters through the pipe A, and passing through the regulator valve B, is directed by the guide vanes c into the wheel vanes or buckets D at the correct angle for preventing shock from impact. After passing through the wheel buckets the water falls away at as low a velocity as circumstances will permit through the open- ing or tail-race E. The supply of water is regulated by the hand-wheel attached to the screw F which operates the lever G, and so causes motion of the slide valve u, which admits the water to the required number of guide passages. This 266 HYDRAULIC POWER ENGINEERING. TURBINES. 267 method of governing is well adapted to impulse turbines, and has no appreciable effect on the efficiency. Fig. 148 illustrates the general arrangement of a Pelton wheel, which is a type of axial flow impulse turbine. The water leaves the jet A at a velocity dependent upon the head of water available, and meets the cups or buckets on Fig. 148. the wheel rim with as little shock as possible. The buckets are in the form of two hemispheres, joined together at the centre by a straight thin rib. The water meets the rib, and is divided into two streams, one going each way and acting on the curved surfaces of the buckets as the stream of water does in any other form of impulse turbine. The speed of the wheel should be such that the water on discharge from the buckets is almost stationary. 268 HYDRAULIC POWER ENGINEERING. Fig. 149 shows an axial flow reaction turbine, which, though much like an impulse turbine in general appearance, is so proportioned and erected that the vanes are always full of water or drowned, and the water is discharged under the water level of the tail-race. The action of the water on Fig. 149. the vanes is similar to that given in the general explanation, but the velocity of the water through the wheel is not necessarily uniform, but depends on the sizes of the open- ings for outlet from the fixed guide vanes, also the outlet from the wheel vanes. Where the openings are narrow, TURBINES. 269 the velocity is correspondingly great, and where wide, corre- spondingly small, as in a pipe of varying diameter. Reaction turbines are frequently fitted with suction tubes which permit of the w r heel being placed at a height above the tail-race level dependent on conditions to be afterwards explained. The suction tube may alter the velocity of flow through the wheel according to its area of outlet and the pressure energy remain- ing in the water at the time of outflow. Fig. 150 shows the usual type of thrust- bearing used in turbines having a vertical shaft. The arrangement will be better understood after an examination of Fig. 149. The vertical shaft A rests on a massive foundation, and carries at its upper end a fixed oil cup which contains the fixed steel block B. The mainshaft c carries a gun -metal block D which rests on the block B. The mainshaft c passes through a plum- mer block not shown in the figures, which pro- vides lateral stability. The turbine wheel is supported by a hollow cast-iron shaft suspended from the main shaft c by the lantern E, which carries a brass bush F for steadying the upper end of the vertical shaft A. The turbine wheel is supported laterally by a brass bush carried by the lower end of the hollow cast-iron shaft, and fitting the vertical shaft A. Fig. 150. 2/O HYDRAULIC POWER ENGINEERING. The nut G allows the turbine wheel to be adjusted vertically to compensate for the wear of the thrust block D. There is an immense variety of turbines, but the more important types are (i) The Fourneyron turbine, in which the water flows from within the wheel outwards, and at right angles to the axis ; (2) the centre vent turbine, in which the water flows from the outside of the wheel towards its centre, also at right angles to its axis ; (3) the Jonval or parallel flow turbine, in which the water flows through the wheel parallel to the axis ; and (4) partial turbines, which may be of either of the other types, but in which the water flows into the wheel only round a portion of the circumference* In all turbines the water is conducted by a set of fixed guide curves or plates into the revolving wheel, where it meets with buckets or curved partitions against which it impinges, causing the wheel to revolve. CHAPTER XIX. IMPULSE TURBINES. IN designing a turbine to utilise the energy of a supply of water under a head or pressure, there must be known the quantity of water flowing, and the head or pressure available. The fullest particulars as to variation of supply, highest flood levels, minimum supply during summer months, should also be ascertained if the proposed turbine is to meet the requirements to the best advantage. Where the fall is great and the quantity of water small, the choice must be in favour of an impulse wheel with partial admission, as a reaction turbine would require to be so small and to work with such a high number of revolutions that the design would become unsuitable if not impossible. If the head or fall is only a few feet, and the water supply fairly regular, as is the case where a reservoir or pound is used, a reaction turbine is very suitable, as it is not affected by change of level in the tail-race caused by flood, provided there is a corresponding rise in the top level ; whereas an impulse turbine would require to be placed at a sufficient height above the level of the tail race as to ensure that the flood shall never reach the wheel. The chief objection to the reaction type as frequently constructed is the inability to economically supply varying power ; so long as the power is the same that the turbine was designed to supply, a very good performance may be expected, but if a greater or less power is required the efficiency falls off rapidly. It will be seen that many reaction wheels are unsuited to a situation where the water supply falls short in dry weather, as if the wheel is designed to give 272 HYDRAULIC POWER ENGINEERING. good results for high powers, the power given out with a limited supply will fall so much as to be practically useless. On the other hand, if the wheel is designed to be economical at low powers, it will never give out large powers, although there may be a large water consumption. Reaction turbines have been used in conjunction with impulse turbines, in which case the reaction wheel is set to work at its most economical power, whilst any alteration in power is obtained by regulating the supply to the impulse wheel. Before commencing the design of an impulse turbine, the actual velocity of the water at the guide passages must be ascertained. If the water enters the guides from a long pipe or open channel and vertical pipe, having already dis- cussed the formulce in a previous chapter, we can calculate the actual effective head //, after allowing for frictional and other losses. This head should be calculated from the outlet level of the guide passages, allowance being made for the height h above the tail level to allow for the buckets of the wheel, as shown in Fig. 151. The velocity c of flow from the guide passages will then be '=-95\/^ (0 .95 being the value of a coefficient taken from actual obser- vation. IMPULSE TURBINES. 273 The next step is to find the total outlet area of the guide passages necessary to pass the maximum quantity of water. If the area were only made large enough to pass the quantity of water flowing with the velocity c, it would be found that the full quantity would not flow, as there is a certain amount of obstruction from the vanes passing across the guide passages. A smaller velocity is assumed in calculating the area of the openings having a value of .89^, so that the formula becomes A=Q - - (2) .89^ in which Q represents the quantity of water in cubic feet per second, and A the required area in square feet. We have now two more dimensions to settle, namely, the width of the buckets and the radius of the wheel ; either of these can be adjusted to requirements by an alteration of the other. Before proceeding further a trial radius should be decided upon, also the angles a and a., (see Fig. 152). The wheel velocity is fixed between narrow limits by the velocity of entry of the water if the turbine is to be a really efficient machine ; as is also the angle a of entry. We will try to explain the reason for this by the aid of the diagrams (Fig. 152). We have already observed in our preliminary remarks that the less the value of ?/, the velocity of exit, the greater the efficiency of the turbine, while the direction of inlet does not of itself affect the efficiency, except that no turbine has yet been designed in which the velocity of u can be regulated without adjusting the angle of inlet a. From the point o draw c, representing to scale the abso- lute velocity and direction of the stream passing through the guide passages of a turbine. Draw c v as shown, and com- plete the parallelogram by drawing w lt the wheel velocity. For the present argument we will assume that the velocity c., of exit is the same as c v and that a/., is equal to w v S 274 HYDRAULIC TOWER ENGINEERING. The direction of w. 2 must of necessity be parallel to 7'j, while the direction of c.j may be altered at will. Select a direction for c. y making any angle a. 2 with the ordinate Oy ; complete the parallelo- gram, and obtain the corresponding value of //. In all the diagrams the angle a. 2 has the same value. In the first dia- gram, by selecting a ver- tical direction for c v and consequent value of aj = o, the value of c l is small, whilst it\ is large, giving u a forward direc- tion and high velocity. In the second diagram c v and u\ have been made equal to each other, and the angle /3 (= 90 - aj) is con- sequently bisected by the line c. c t and w. 2 being the same in value as c l and w v are equal to each other, so that u will have a slightly for- ward direction and small value. In the third diagram c l has a large value, and W-, a small value, so IMPULSE TURBINES. 275 that on drawing out the parallelogram c. 2 w 2 the velocity u is found to have a large value in a backward direction. Now, as we have previously shown that u should be as small as possible, it is evident, without further demon- stration, that ^ should be slightly greater than w lt and consequently c. 2 greater than w. 2 . To what extent this rule may be followed in practice, and the modifications necessary in the various designs of inward, outward, or radial flow turbines, will be further explained. In an axial turbine the value of w^ being the same as w lt it would appear at first sight that the conditions above stated apply without correction ; but this is not so, as, owing to the height h (Fig. 151), the stream of water will increase in velocity in passing through the vanes, the additional velocity being represented by tj2g/i ; but as there is friction be- tween the vanes and the stream, the velocity of the water will be reduced below the theoretical amount, so that the complete formula becomes t* = (e*+,g*.)-L (3) The value of/ is variable between .05 and .1. The value of h cannot yet be fixed, so that in calculating^, an assump- tion must be made, 6 inches to i foot being a suitable dimen- sion. It is scarcely necessary to remark that with high falls, and consequently high velocities, h may be neglected in the preliminary calculations, as its effect becomes scarcely noticeable ; whereas with a low fall the height h forms a considerable portion of the total head. In an inward flow radial turbine W 2 is less than w^ by an amount dependent upon the ratio of the depth of the vane to the radius, and as c. t should be slightly greater than w , the value of c l (greater than c. 2 ) may be temporarily fixed approximately equal to w-^. Fig. 153 will make this clear. Fig. 154 shows the diagram for an outward flow radial turbine, in which >., becomes greater than w^ by an amount 2/6 HYDRAULIC TOWER ENGINEERTNG. dependent upon the ratio of the depth of the vane to the radius, c., must be slightly greater than /.,, and consequently considerably greater than w r Having arrived at suitable values of 278 HYDRAULIC POWER ENGINEERING. parts of the vane are not at the same radial distance, the quantities w l and w. 2 have variable values. The centrifugal effect may be easily counteracted, as will be seen with reference to the diagram (Fig. 155). The values of the angles 04 and a. 2 having been fixed, and the design of the turbine completed in every way, the absolute path of the stream of water through the turbine may be easily found by measuring the length of the turbine vane in terms of ^ : now mark off P l P the same multiple of w. 2 , and the point P indicates where water entering at the point O would leave the vanes. If, for example, the length of vane equals 2 x . By altering the area A. 2 w r e not only alter the velocity c. y but also the velocities c and c v and, whereas the velocity c for impulse turbines has one particular value for any given head of water, the velocity c for reaction wheels may have a comparatively large range of values for any given head. Fig. 158 shows what takes place if the value of e., is the REACTION TURBINES. 28 1 same as e lt or if the vanes are of the same width throughout. In the Figs. 157, 158, 159, we have taken the same values for a and a 2 for the sake of comparison, while a has also been taken equal to a. 2 . In Fig. 158, A 2 will consequently equal A, and c.-, will equal c. Taking the value for w 2t which makes u vertical, we see that ^ enters the vanes in a vertical direction. This diagram is typical of the design of the Jonval turbine as conducted on the European continent. In Fig. 159 the wheel vanes have been contracted, causing diminution of the area A. 2 in relation to A, and consequent increase of the velocity c. 2 above c. Applying the correct value for a/.,, c^ is given a backward direction. Thus we see that for any values of a and a., by altering the ratio of the areas A and A 2 we can produce different values of c for the same head of water. In the diagrams the same length of line has been taken to represent the value of c. 2t but it must not be supposed on this account that c. 2 has the same arithmetical value in each case. As we have not yet investigated the formulae for calculating the true value of c under any con- ditions, some value had to be assumed in order that the diagrams could be drawn out, so that, while in each diagram the values of r, f lt c^ w v w. 2 , and u are proportional to the lengths there given, the diagrams must not be compared by measurement. The correct value of c for any conditions must next be in- vestigated. As the turbine is filled with water, and the flow at any point is governed by the formula Q = Av, the energy contained in the water at any point is evidently represented by the hydrodynamic equation already investigated in Chapter I., or, if // represents the useful head of water, the energy of i Ib. of water is If /^ represents the pressure energy of the water on leaving the guide passages, then the total energy of the water on 282 HYDRAULIC POWER ENGINEERING. Figs. 157, 158, and 159. REACTION TURBINES. 283 leaving the guide passages is /^-f . Now this energy, neglecting losses, must balance the energy h m of the total head of the water, measured from its surface to the level of outflow from the buckets, as shown in the diagram Fig. 160, therefore-^- /<,=/,,+ (,) f = Fig. 1 60. As, however, the water level in the tail-race is liable to vary and rise a height /i. 2 above the outflow level, the useful head h is evidently represented by h m - h.^ so that from equation (i) we get - /i = h m -h.^^-h^ - (2) We must now consider what is taking place in the turbine 284 HYDRAULIC POWER ENGINEERING. buckets due to the change of velocity from ^ to c.,. From the hydrodynamic equation therefore 7i 1 - h z = c -- - (4) By substituting this value for h l - h* in equation (2) we get The values of t. 2 and ^ may now be expressed in terms of ^, since c, : c : : A : A, "*--.- - - (5.) similarly c ^~~\~ c ~ (5^) Substituting these values in equation (5) A \ ^~ (6) .'. C= j2gh.V' (7) = K x / 2 ^ (8) The solution of equation (7) will give the value of c for the corresponding values of A, A 15 and A L> . The equation in this form is not suitable for direct use, as, though we may REACTION TURBINES. 285 assume values for A and A. 2 , the value of A x is entirely dependent of the values of A and A. 2 and the angles a and a.,. So that having selected the values of A, A 2 , and a 2 is necessary to draw out a diagram similar to Figs. 157, 158, or 159, and so obtain the corresponding values of A l and a r In drawing out the diagram c., should first be drawn in the correct direction making the angle a 2 with the vertical, and having a length not less than i inch, preferably 2 inches. iv. t must now be drawn so as to give u a vertical direction. The length of c may now be calculated from equation (50) and drawn in a direction making the selected angle with the vertical. On drawing w^ equal to w. 2 for an axial flow turbine and completing the parallelogram the value and direction of ^ are obtained. A l may now be calculated from equation (5^). Equation (7) may now be solved, and the value of c ob- tained, whence the other values, c v c. 2 , w^ w. 2 , may be obtained either graphically or by calculation. This com- pletes the calculation necessary in the case of an axial flow turbine working under the conditions assumed in the Figs. 157, 158, 159. If the value of u resulting is considered too high, then the process must be repeated with an altered ratio of A : A , and if necessary altered values for a and a. 2 . If the calculation has to be made for an outward or inward flow radial wheel the only altered condition is in the value of w lt which will not equal w. 2 , but will have a greater or less value. If r^ and r. 2 be the radii corresponding to it\ and w. 2 respectively, then w l : w. 2 : rrj : r, ..W-MPi-^ - - (9) 2 r, This new value for ii\ must be used in drawing out the diagram, and consequently c and r x will have an altered ratio to c. 2 . This operation may be performed graphically, as in Figs. 153, 154, Chapter XIX. 286 HYDRAULIC POWER ENGINEERING. As it is not always convenient to resort to graphic methods, we may evolve an equation from equation (6) in which AJ is expressed in terms of A, A 2 , sin a and sin a. 2 . Referring to any of the diagrams, Figs. 157, 158, 159, w* may be expressed 7e 2 = ) sin a 2 - - (10) therefore by (9) = -4 a> = > s sm (II) Fig. 161. The whole operation of fixing the values of c, c^ c.# w v w.-> may be performed by the following very simple graphic method : Having selected a and a.,, and the ratio i\ : r.> in the case of inward or outward flow turbines, draw out the diagram to any scale as shown by the light lines in Fig. 161. Set up a vertical OG and draw OF at right angles equal to AB in the diagram, and with the length CD mark off FG completing -REACTION TURBINES. 287 the triangle OFG. From G set off GH at right angles to OG and equal to AE. Join OH. Then OF = f l5 FG = fo, and GH = ^ to any scale. And FG 2 -OF 2 = OG 2 , or c.? -^ = OG,. Again GH 2 + OG 2 = OH 2 , or ^ + ^0-^2 = OH 2 . From equation (5) ti'cf **?-.*&> therefore OH 2 = 2gh = v 2 , where v represents the velocity due to the head //. Extracting the roots The velocity v due to the head h for the case under con- sideration may now be calculated and marked off from OH to any suitable scale (say 20 feet to i inch), as shown by the thick line in the diagram. Draw r, r 19 t. 2 parallel to GH, OF, and FG respectively, and scale off their lengths to the same scale that was used for v. Apply these corrected lengths to the diagram, and measure off ?'j, w. 2 , u, and the investigation is complete. The head h is the total head, less about 15 per cent. allowance for losses by friction. According to the properties of triangles c-f may be ex- pressed r x 2 = c- + '} 2 - 2cw l sin a - - (12) substituting the values for w^ and n^ given by (n) and simplifying but by (5/;) ^ 2 = <: 2 . ( -J , therefore the quantity contained /A \ 2 in the brackets in (13) equals ( ) . \ AT / 288 HYDRAULIC POWER ENGINEERING. /A\ 2 f /rA 2 /A\ 2 . r, A . } , =-^14. -l sin a.,-- 2 - 1 . .sin a. sin a., - (14) VAj/ \rj '\A. 2 J r.,A. 2 substituting this value in equation (6) c 2 -[ i + ( \ - i -f ( - 1 j . ( j sin a., 2 - 2- 1 . . sin a. sin a., (-5) simplifying and extracting the value of c c= ^\ 'I i - (- 1 } 2 . sin a A + 2-1. A. sin a. sin a., A / I VQ/ " ) r A (16) The values of r, r 15 ,, K/J and 7f. 2 , as investigated by the above-described methods, are the theoretical values, and do not take into account the losses caused by friction of the pipes and vanes. There are several separate causes for loss in reaction turbines, namely, friction of vertical supply pipe ; friction of guide vanes ; friction of wheel buckets ; loss by leakage between guide vanes and top of wheel buckets ; loss from energy represented by the velocity u ; and when the wheel is not running at its best speed, loss by impact due to the angle of inflow a t being different to the corresponding angle of the wheel buckets. The first of these losses may be calculated by the formula By making the velocity v small, such as 3 to 5 feet per second, the head lost on this account is very small. Values ofy^ have already been given in Chapter II. The head lost by friction of guide vanes is given by the equation *=/. - - - (18) in which /has the value .u, determined by experiment. REACTION TURBINES. 289 The losses occurring through leakage between the guide vanes and wheel are dependent on the pressure /t l at that point, and on the width of opening between the guides and wheel, usually | inch. As an attempt to calculate this loss would require a good many assumptions to be made, it is advisable to make an allowance as observed from good examples of turbines. The loss by leakage is found to be fairly represented by about 4 to 5 per cent, of the total head, so that we may write the equation //..^.o^-H 10.05 H - (19) It may be here observed that on account of this leakage the velocity c will actually rise by 4 or 5 per cent, above /^ what is required by the ratio . In fact the gap be- 2 tween the guides and wheel is a sort of useless addition to the areas A 1 and A.,. The losses occurring in the wheel buckets may be calcu- lated by a modification of equation (18), for instead of a uniform velocity we have a velocity varying from t\ to r 2 . Assuming that the change from c v to c., takes place by uniform acceleration, then the equation becomes in which /has the same value as before. The energy lost in every pound of the off-flowing water due to the velocity // is represented by the equation *i-g - - - () By combining the above equations the useful head // u , representing the proportion of the total head H, which is converted into useful work, may be found. // u = H - (/^ + /i u -f //! -f // 31 4- /r 41 ) - (22) T 290 HYDRAULIC POWER ENGINEERING. The head h for use in solving the equations (7) and (16) is given by the equation /* = H -(//! + //,! f/^ + 7^) - (23) consequently ^ u = //-// 41 (230) The equations (17) to (23) are not in a form for direet use, as they contain the quantities c, c^ .,, z/, which are unknown until equation (17) or (23) has been solved. They might, however, be worked out in suitable form and included in equations (7) and (16), but there is then the disadvantage that all operations are conducted at once, and it becomes difficult to follow the effect of the various losses. A very near approximation to the value of c, corresponding to the head h, as given by equation (23), is obtained by first calculating c, f lt c. 2 by equation (7) or (16), and then using these values in solving equation (23). This method is, of course, not strictly correct ; but as some of the quantities in the equations (17) to (20) are only approximate, it is useless to be too critical. An example worked out for a head of 10 feet, and A = A.,, a = a 2 = 6o, as shown in Fig. 158, gives a loss of head of 1.66 feet, or h = H - 1.66 = 10 - 1.66 = 8.33, or 83.3 per cent., or a loss of 16.66 per cent, due to friction. Experiments conducted on existing turbines give values of 82 to 86 per cent, for //. There is a further loss of about 12.6 per cent, due to the velocity u of off-flow, so that the useful head // tl given in equation (22) is 4 r H-^(i.66.+ i.a6) = 10 - 2.92 = 7.08, or 70.8 per cent. Allowing 2.8 per cent, for shaft friction leaves 68 per cent, for the brake efficiency of the turbine, which is a good performance for the design under consideration.' By in- creasing a = a 2 to 66 the brake efficiency is improved to REACTION TURBINES. 29 1 73 per cent., and by further enlargement of the angles a. and a. 2 a better efficiency may be expected. The calculations for the velocities being completed, the proportions of the turbine, such as width of guide and wheel passages, diameter, number and depth of buckets and guide passages, may be settled. If the wheel is required to give a certain brake horse-power, the corresponding quantity of water, Q cubic feet, can be calculated from the value // in equation (22). Q _B.H.P. x 33000 , } ^ 60 x 62.27 x// u The area A necessary to pass this quantity is A = -^, so that the width of guide passages e l may now be calculated from the formula A in which r^ represents the mean radius for an axial wheel, and z l the number of guide vanes, and /j their thickness. As, however, the passage of the wheel vanes across the openings of the guide passages the effective area A is diminished below the value above found, so that if z l is the number of wheel vanes, and /., their thickness, the equation becomes A , } In the same way the width e., of the wheel at outflow is found by *-- - 2 ~ (26) 27T;-., cos. a. 2 - z.yt., If the diameter chosen gives unsuitable values for e and ,, a new diameter must be selected, and the calculation repeated. The number z l of guide vanes may be found by making the width of opening of passage, measured at right angles to the direction of flow, equal to about 5 inches. Then HYDRAULIC POWER ENGINEERING. number s., is then given either equal to z l or slightly greater. The depth of the buckets may now be settled so as to give a change of direction to the water not too abrupt. The dimensions satisfying this condition varies from about 8 to 1 2 inches. The depth of guide passages may be from J to i of the depth of the buckets. Instead of discharging the water from the buckets direct into the tail-race, it is evident we may lift the wheel some 4E3 -*- l i I i ^f~" Fig. 162. height above the tail-race level and connect a hermetically sealed pipe, called a suction tube, to the guide passage frame enclosing the wheel from the atmosphere, and having an opening under the tail-water. If this pipe be filled with water, the rate of flow in it, when the turbine is at work, will depend upon its sectional area A 3 , and compared with c the velocity in this pipe will be ~c, and making the outflow area Aq REACTION TURBINES. 293 A 4 , the velocity of off-flow becomes c. If the velocity of 4 off-flow c 4 is the same as //, as it will be if the suction tube is of annular form, as shown in Fig. 162, having a width e. 2 , then the calculation is the same as that for a turbine without suction tube. There will, of course, be greater loss owing to the increased wetted surface of the annular suction tube above that of a plain tube. Fig. 163. If, now, the inner ring be removed, the off-flow area A 4 appears to have the full area of the suction tube, but whether this is so or not depends on several circumstances. The water in flowing from the wheel with the velocity u cannot at once alter its velocity to ^ 3 = ^ 4 to suit the area of the suction tube A 3 = A 4 . The result is that there is a central core of comparatively dead water somewhat of the shape shown in Fig. 163. As the water passes down the suction 294 HYDRAULIC TOWER ENGINEERING. tube the velocity changes from u by values approaching nearer and nearer to r 4 , until, if the tube is sufficiently long in proportion to its diameter, the velocity 4 is reached. If the tube is short and of large diameter, the velocity outflow A c will not be represented by c, but will have some higher 4 value, as the whole area A 4 is not in that case effective. Fig. 164. This uncertainty of the velocity r 4 may be overcome by putting a bottom plate into the suction tube and curving the lower edge outwards to form a lip as shown in Fig. 164. The area A 4 has now a definite value, and if an inner tube is to be used, it should be somewhat similar in shape to the dotted line in Fig. 164. Experiments on turbines prove that if this inner tube is only an approximation to the true REACTION TURBINES. 295 shape, the efficiency of the wheel falls below the efficiency without an inner tube. Generally it is advisable to leave out the inner tube. By altering the area A 4 the velocity r 4 may be altered, but in altering it will have an effect on the other velocities c, f lt c.,, so that a new equation must be evolved before c can be ascertained. Referring to Fig. 164, the useful head h is represented by // m - 7/ 4 , so that as before A= A. ->*,=>*, -4 4 +^ (27) adding //., - //., to each side // - //! - //,, + 7/._, - // 4 + - (28) By equations (3) and (4) 7/j - //., has been shown equal to c 1 c 2 - - 1 -, similarly " therefore ^-^4 = ^- - (30) *g 2g Substituting these values in equation (28) *-P+ = 4 = 1.2 % 17.0% Shaft friction ..... * 5 % 22/, Then 100 : 374 : : 78 : B.H.P. B.H.P. = 291.7, or say 280 H.P. available. The dimensions of guides and buckets may now be settled. A = ^- = = .08 1 square feet. .89;- .89 x 138.4 This is equivalent to an opening 3 inches wide x 4 inches measured at right angles to direction of flow. e l for guides = 3 inches, and using two guide passages, their opening will be 2 inches each, or 4f inches measured on circumference. The pitch of wheel buckets must not be less than 5 inches, and their thickness is J inch. Number of wheel buckets = 5^L x Jjj4*i2 = ^ By scaling the width of inlet to bucket at right angles to c v and outlet at right angles to r>, their values are 3! and 2J- inches respectively e 1 x 3J- x ^ = e% x 2| x c. 2 .'. e. 2 = 4.9 inches, say 5^ inches to give extra clearance. Collecting the values Q = 10 ft. a =74 c =138.4 ft. ^ 3 in. 11 =33 2 >> 0.1 = 61 c l 80 ,, tfj (for buckets) = 3i in. H.P. -374 03=78 c,= 76 ft, - 5? B.H.P. =291 w 1 = 63ft. 1\= 5ft. 5 in. z v =2 Load =280 H.P. w. 2 = 74,, r.,~ 6 ,, 5 ,, z 2 = 38 Regulation as shown in Fig. 147. 310 HYDRAULIC POWER ENGINEERING. Example 2 Quantity of water Q = 30 feet per sec. Head H= 15. 6 feet. Max. 33000 Select a = 68 , = 72 A = = 1.17 square feet. Select mean diameter of wheel for axial flow, 3 feet. As h is a large percentage of the total head, c. 2 may be taken approximately equal to c v Draw out the diagram, Fig. 142, making u vertical, and select w 1 = w, 2 = 15 J for trial. Then for c= 28.88, ^ = 15.5, and c. 2 = 16.5 by measurement. By equation (3), p. 275, ^=16.5. The correct values are therefore ^=15.5, ,= 16.5, The brake H.P. may be found c =28.88 velocity due to 13 ft. . '. head lost 1.5 ft. =9.7 % 'i=i5-5 3-75 \ , 2 / i i n - Depth of buckets 6 inches and guides 6 inches. Regulation by any of the methods shown in Figs. 166, 167, 168. DESIGN OF TURBINES IN DETAIL. 313 Example 4 Design an inward flow radial turbine for the same con- ditions. Q - 30 feet. H-I5.6 feet. Max. H.P.-52.8. Select = = ,666. A, 1.5 =75- ._,= 7 2 - r^ = 2 feet. ^=1-5 feet. Draw out the diagram as in Fig. 157 to any scale, making A c.> = c, and observing ratio i\ : r. 2 . A.) With the dimensions thus formed for c, c^ c. y construct diagram, Fig. 161. Assume a loss of head of 15 / o , and find velocity due to //! = .85H, and mark off this value on the diagram to a suit- able scale, and complete the diagram and scale off values for c, c v c. c =2$ feet. ^1 = 7 55 f. 2 =i6.S w v w.^ u may now be found by graphic methods from c. 2 '! = 21.3 7C>. 2 = 1 6. I - 5-3 a l by measurement = 24. Find brake H.P. By equation (230) h u = h - // 41 = .85!! - 2 S -(.85-.o3)H-.82H .-. Hydraulic losses - 18 / o Shaft friction - 4 / Then 100 : 78 : : 52.8 : B.H.P. B.H.P. = 41.18. Say 40. 3H HYDRAULIC POWER ENGINEERING. The dimensions of the wheel may now be settled. A = -^ = ^=i.2 square feet. ' 2 5 Select z l = 1 8, z 2 = 20, t l = / 2 = .02 feet. Then (by equation 25) *, = _ =.415 f 2 X 3.14 X 2 X .258 -(l8 - .02 + 20 X .02) A., = -i. = _3 = 1.8 square feet. c. 2 1 6. 8 Then (by equation 26) 1.8 2 X 3.14 X 1.5 X .309 - (20 X .02) Revolutions per min. = } - x 60 = 102. 3.14x4 Collecting the values Q -30 ft. a =75 c =25 ft. 2 5 x ^- = .o74QH, where H is the available head 55 measured in feet. The water should have a velocity greater than the cir- cumference of the wheel ; thus if the wheel has a peripheral velocity of 6 feet per second, the water should be flowing at about 10 feet per second. This velocity is obtained by falling through a height iQ 1 =2gh or /= I( - = 1.55 feet, 64.4 or the water should enter the wheel at a position 1.55 feet below the surface level of the head water. To remedy the practical losses arising from the non- clearance of the tail water, and to enable the wheel to be HYDRAULIC POWER ENGINEERING. immersed beyond the i foot extreme limit of immersion for an overshot wheel, the breast wheel, as shown in Fig. 173, is employed. The water acts by weight only, dropping almost vertically into the buckets through the openings in the pen trough, Fig. 172. which is shaped to the circumference of the wheel. The masonry breast or curved edge adjacent to the wheel is not employed in the large wheels of this type where the diameter exceeds 19 feet. The buckets are only partially filled, and the space between the inner edges of the buckets and the wheel shrouding admits of free ventilation during WATER WHEELS. 317 the movement of the wheel. The efficiency of the ordinary breast wheel varies from 70 to 75 per cent. The oldest type of wheels known is that of the undershot, as illustrated in Fig. 174. The efforts of Poncelet led to great improvements in the efficiency of this wheel. It is used for falls up to. 6 feet, acting on the same principle as Fig. 173- the impulse turbine. The stream of water should flow down an incline of i in 10 to impinge upon the curved blades near the bottom of the wheel and leave them with very little velocity and consequent work unabsorbed. The diameter of the wheel should be at least twice the fall, the speed of the periphery between 50 and 60 per cent, of the velocity due to the fall measured to the centre of the inlet HYDRAULIC POWER ENGINEERING. orifice. The depth of the bucket in the radial direction equal at least to one-half the fall. The number of buckets found to be most efficient is 1.6, the diameter of the wheel in feet + 16. Thus with a fall of 3 feet, and for a wheel of 12 horse- power, the diameter will be 6 feet. W///W/MP- Fig. 174. The fall being 3 feet, the velocity due to that height v = % >/3= 13.86 feet per second. Number of revolutions = 22 = 22. 7TO Assuming a duty of 60 per cent., then the cubic feet of water Q required will be which will require a width of 10 feet 6 inches with a depth of stream taken at 7 inches, and a discharge assumed as about 70 per cent, of the theoretical quantity on to the wheel. CHAPTER XXIII. HYDRAULIC ENGINES. UNDER the head of hydraulic engines we propose to discuss the motors in which the hydraulic pressure, acting on a reciprocating piston in a cylinder, causes the revolution of a shaft from which power may be taken for doing work of any kind. Before discussing the best known types in detail, it is advisable to inquire into the causes of loss and means of prevention with a view to the production of an ideal motor. The water pressure available may either be expressed in feet of head or as pressure per square inch, usually the latter for the type of motor under discussion. Whichever form is given, the conversion to the other is very simple. Since a column of water i square inch in section and i foot high weighs .434 Ibs., it is evident that the pressure per square inch in pounds ^.434 will give the corresponding head in feet, or - H, and conversely H x .434 =/. The head 434 H or pressure / being known, the total energy per pound of water can be calculated. According to the hydrodynamic equation the total energy of i Ib. of water is where p represents the actual pressure in pounds per square inch at any point, and* v the velocity of flow at the same point ; while L represents the pressure in pounds per square inch lost from all causes between the source of supply and 320 HYDRAULIC POWER ENGINEERING. the point under consideration. By assuming the source of supply to be close to the cylinder of the hydraulic engine, the quantity L may be taken as equal to o, as by so doing the investigation will be much simplified. We have now two quantities to deal with, namely, -^ , representing the 434 head producing the pressure/ in pounds per square inch of the water passing into the cylinder; and representing the 2^ energy absorbed in producing the velocity v of the flow into the cylinder. We have already (Chapter II.) examined the conditions necessary for the change of velocity of the water without loss of energy on entering the cylinder. In a perfect design of motor the passage from the valve to the cylinder would require to be conical or trumpet-mouthed, allowing a change of velocity to occur without loss by eddy currents. Having arranged for the economical entry of the water to the cylinder, we are now at liberty to examine its action upon the piston, and as the water entering the cylinder must have a velocity corresponding to that of the piston, we must first investigate the true velocity of the piston at each part of its stroke. In the accompanying diagram, Fig. 175, let A p> c D represent the crank path of a hydraulic engine, then A c will represent the length of the piston stroke. When the crank-pin is on the dead centre A the piston has no velocity, whereas when the crank-pin arrives at B, assuming the con- necting rod of infinite length, the forward velocity v of the piston is equal to the circumferential velocity z> c of the crank-pin ; for all intermediate positions of the crank-pin between A and B the piston will have a series of velocities varying between o and v c . The values of v may be ex- pressed as a function of v c . Take any point E in the crank path, and draw a tangent E G to represent the velocity z> c , and resolve the velocity v c into its components EH, H G, in HYDRAULIC ENGINES. 321 which E H represents the horizontal velocity v of the piston corresponding to the point E. Let fall the vertical E F, then the triangle o E F is similar to the triangle of velocities E G H, so that v : v c : : EH : EG : : EF : EO v EF - * iTEO = sm '' therefore v = v c s\n9 - - (2) The velocity v of the piston, therefore, varies as the curve of sines, and its value at any point of the stroke may be found by the aid of a table of sines, or by describing a semi- circle with radius OB = ^ C to any suitable scale, when the ordinates, such as E F, E 1 F 1 , measured to the same scale, will give the velocity v for the corresponding points F F 1 of the stroke. Having obtained the values of v t we can now by the aid of the hydrodynamic equation (i) find the corresponding values of/, as E may be substituted by - - ;/ being the pressure 434 per square inch when the water is at rest. The equation then becomes E= P -=-- + -- (* .434 .434 2g /=A-^ x -434 - (3*) The values of/ thus obtained may be plotted as ordinates (Fig. 176). The curve thus produced will dip from the commencement of the stroke to the centre, when, owing to the decreasing velocity, it will again rise by a similar contour until at the end of the stroke it has the value p Q as at the commencement. If the piston had moved forward through the stroke with a very small velocity, the pressure p Q would have remained constant throughout the stroke, so that the work done per X 322 HYDRAULIC POWER ENGINEERING. square inch of piston area would be/ S foot-pounds, S being the length of stroke in feet. But/ S represents the area of the parallelogram A i L c, which therefore is a measure of the total available energy per square inch of piston area. Figs. 175, 176, and 177. Instead, however, of the pressure p we have the varying pressure /, so that the area of the diagram A i K L c repre- sents the work done per square inch, of piston area by the va-ying pressure /. The difference i K L between the dia- HYDRAULIC ENGINES. 323 grams AILC and A i K L c, therefore, represents the kinetic energy due to the varying velocity of the water, and is a V" function of the quantity in the hydrodynamic equation. 0> The diagram A i K L c gives the curve of pressures acting upon the piston, supposing that the base of the piston is always close up to the valve opening without any intervening water ; this, however, is not the case, because as the piston recedes there is an increasing quantity of water to be ac- celerated. We will now proceed to deduce the curve of pressures necessary to produce this acceleration. It is well known in connection with steam engines that the force / a necessary to produce acceleration of the reciprocating parts is represented by the equation in which R is the radius of crank circle, x the distance travelled by the piston at any moment, and v c the crank-pin velocity, all expressed in feet. Since ~~f>v at the com- mencement and termination of the stroke has the values fr and - B, the equation becomes K K A-B'- - - (5) for those points, the 4- sign representing accelerating force, and the - sign retarding force. Now the column of water to be accelerated may be con- sidered as a piston, and we may assume for the time that its weight w per square inch of piston area is that of a column of water i square inch in area, and having a length equal to the length of the piston stroke. If the calculation be made, we get the straight line curve MN (Fig. 177), of which the vertical ordinates, such as A M, c N, represent the accelerating or retarding force / a at the corresponding point of the stroke 324 HYDRAULIC POWER ENGINEERING. for the assumed weight w. But as the only point of the stroke at which w really represents the weight of the water is at the end B, it is evident that the corresponding value of pi is equal to the true value / b for the varying water column. At the commencement of the stroke, as w = o, so / b = o, and the values of / b for any intermediate point may be found by multiplying the value of / a given by equations (4) and (5) by the ratio ;,, or w vMR-x) x The operation may, however, be more easily performed by graphic method on the diagram (Fig. 177) by dividing AC and CN into a similar number of equal parts, and drawing radial lines from o to c N and A M, and ordinates from A c, when points of intersection will be points on the curve by the principle of similar triangles. A o N in the figure repre- sents the curve thus produced, and the ordinates / b must be subtracted (observing the signs 4- and - ) from the ordinates p in Fig. 176; thus we obtain the ordinates / t in Fig. 178, which may be expressed by the equation (30 and 6 com- bined * The diagram A i K p c thus produced is the diagram of work for the outward stroke of a hydraulic engine satisfying the condition laid down, namely, absence of hydraulic losses from friction between the source of supply and the cylinder. This diagram must accordingly have an area equal to the area of the parallelogram A i L c B, and consequently the area above the line i L must balance the vacant area below that line, or area AONC, Fig. 177, equals area i K L, Fig. 176. That this is so is capable of mathematical proof. So far we have made no mention of the back pressure due to expelling the exhaust water. As the velocity during HYDRAULIC ENGINES. 325 exhaust is the same at each point of the stroke as the velocity during the working stroke, the back pressure will be repre- sented by the ordinates of the diagram Fig. 176, added to the ordinates of the diagram Fig. 177, and the combined area A Q s, Fig. 179, represents the energy lost on this account. Since the area A o N c is equal to the area i K L, the area A c Q s is evidently equal to twice area i K L. The only condition which remains to be investigated is when a length of pipe / of diameter d intervenes between the valve opening and the cylinder, or when a similar pipe of any length and diameter is attached to the exhaust outlet. ,It is evident that the velocity of the water in the pipe must be dependent upon the velocity v of the piston at every point of the stroke. Since Q = A.V, and the areas of the pipes vary as the diameters squared, the velocity 7\ in the pipe varies in relation to v inversely as the squares of the dia- meter d of the pipe and D of the cylinder, or 7' : v : : D' 2 : d' 2 (8) Similarly the weight it\ of the water in unit length of the pipe varies in relation to w the weight of unit length of water in the cylinder directly as their diameters squared, or /! : w : : d- : D 2 wd* * ; i= D T (9) As v is a function of ?' c we may substitute the values i\ and '! for v and w in equation (5), when / x or , ' w ?' and w being taken equal to /x.43^, p c will represent the accelerating force per square inch of piston area at the 326 HYDRAULIC POWER ENGINEERING. commencement of the stroke. As w is a constant quantity throughout the stroke, the diagram of accelerating forces will be bounded by a straight line curve, as M o N in Fig. 177. The diagram so produced must now be subtracted from the diagram A I K P c, Fig. 178, to obtain the true values of / t for these altered conditions. A similar investigation may be made for the exhaust pipe, and the diagram, so pro- duced, added to the dia- gram ACQS, Fig. 179, taking care to observe the -f- and - signs. We do not propose to investigate the energy lost by friction of pipes and bends, as the matter has already been treated in Chapter II., and the for- mulae there given may be applied, so that we are now in a position to examine some of the leading designs of hydraulic engines, and note to what extent it has been found advisable to follow the precise arrange- ment of details demanded by our preliminary investi- gation. Fig. 1 80 shows a sectional elevation of a Brotherhood engine, while Fig. 181 shows a cross section of the same. The design consists essentially of three cylinders A B c, fitted with single acting rams or pistons DE F, and placed at 120 to each other. These three pistons operate by means of connecting rods one common crank-pin G, which imparts circular motion to the shaft H. The pressure water is Figs. 178 and 179. HYDRAULIC ENGINES. 327 admitted from the supply pipe I to each cylinder during the outward stroke of its piston by means of a revolving valve K, which is driven by the plate L attached to the end of the crank-pin G. The valve K is of simple construction, having a passage M ending in a splayed mouth of such dimensions that communication between the supply pipe i and cylinder port M 1 is maintained through 180, or a half revolution of the valve. The alternate half of the valve is cut away, so as to allow free escape of the exhaust water during the other J L Fig. 180. half revolution, thus permitting the exhaust water to flow away by the pipe N. The port face o is composed of lignum vitse. Each piston is operated upon by pressure water during 180 of the revolution of the crank-pin, and, as there are three cylinders, there is no dead centre ; the turning moment applied to the crank -shaft is, moreover, almost uniform, as will be seen by reference to the polar diagram, Fig. 182, in which vectors such as o A, o P>, o E, o F represent the turning moments for the corresponding positions of the 328 HYDRAULIC POWER ENGINEERING. crank- pin. These vectors also represent the velocity of flow in the supply pipe i, which is also very uniform. In our preliminary examination we took the supply as being close to the cylinder, which we now see was justifiable, as the only water which is at rest at the ends of the stroke is the small quantity contained in the port M 1 and the cylinder clearance space. The flow in the pipe i may be rendered practically uniform by placing an air bell or a shock valve similar to Fig. 69, of suitable size, as close as possible to the r i h Fig. 181. D Fig. 182. valve. It may be pointed out that the piston stroke is very short, thus allowing a moderately high number of revolu- tions per minute without excessive velocity of the entering and exhaust water a condition tending, as we have seen, to improve the efficiency of the engine. In the figure the port M 1 is shown entering the cylinder with an abrupt enlarge- ment, thereby causing loss by eddy currents; but owing to the high pressure (700 Ibs. per square inch and upwards) usually applied to these engines, and the comparatively low velocity HYDRAULIC ENGINES. 329 of the entering water, the loss so caused forms a very small percentage of the whole energy imparted to the engine. Of course with low pressure, and the same velocity of entry, the losses are of moment, and the conditions laid down in our preliminary examination require to be rigidly adhered to if Fig. 183. the engine is expected to show a satisfactory efficiency. The energy lost per square inch of piston area from this cause may be ascertained by an application of equations (30) and jj (10). Equation (3^) must of course be multiplied by ^ 330 HYDRAULIC POWER ENGINEERING. if v be taken as the piston velocity as before, when the re- sulting diagram gives the losses per square inch of piston area. In applying equation (10) the second half of the diagram will evidently disappear, causing the energy and pressures represented by the first half to be lost or subtracted from the diagram of work. Fig. 183 shows in plan the general arrangement of a large size Armstrong engine in which three oscillating cylinders A u c are used, placed side by side, and operating a three-throw crank shaft D, having the cranks placed at 120 to each other, so that the turning moment applied to the crank shaft is precisely similar to that already described in reference to the Brotherhood engine. The valves E F G controlling the admission of water to the cylinders are of the reciprocat- ing type, and are operated by connecting links worked from oscillating studs on the gud- geons of the cylinders. The water passes from the valves by pipes H i K connected to the gudgeons by a swivel union of the type shown in Fig. 62, and so through ports in the gudgeons to the cylinders. In the smaller size of these engines, instead of the three reciprocating valves E F G, each cylinder is fitted with a valve of the type shown in Fig. 184, in which the oscillation of the cylinder operates the valve. The pressure water is admitted through the pipe L, and the oscillation of the HYDRAULIC ENGINES. 331 cylinder causes the oscillation of the valve M attached to the cylinder gudgeon, thus opening the port N to the pressure water L. The port N communicates through a port in the gudgeon with the cylinder, thus allowing pressure water to enter the cylinder so long as the port N is open. During the progress of the stroke the oscillation of the piston, and consequently that of the valve M, is reversed, so that when the piston is fully out the valve has again closed, and occu- pies the position shown in the figure. The further oscilla- Fig. 185. tion of the cylinder will cause the port N to open to the space o, which is in direct communication with the exhaust p. Valves of this type are liable to cause serious frictional losses due to the throttling of the water, as the valve, when nearly shut, is in the form of a long narrow slit. Figs. 185 and 186 show in elevation and plan a three- cylinder Armstrong capstan, fitted with valves A B c of the type just described. The capstan is started in the usual manner by the button D, arranged in the floor, being de- pressed by the operator's foot, thus allowing water to pass 332 HYDRAULIC POWER ENGINEERING. through the valve E to the supply pipe F, feeding the cylinders G H i. The exhaust water is conducted away by the waste pipe K. The valve shown in Fig. 187 is interesting, as being the type used on the early designs of Armstrong engines. In these engines the pressure water was allowed to act on both sides of the piston during the outstroke. The piston rod was made of such diameter that its area was half of that of the cylinder, so that the piston was pushed outwards with a Fig. 1 86. total pressure due to half its area, and the water contained in the forward end of the cylinder was returned to the supply pipe. On completing the outstroke the tail end of the cylinder was connected to the exhaust, while the forward end still communicated with the pressure supply. Thus the pressure water acting on the small area of the front of the piston drove back the piston, expelling the water from the large side to exhaust. By this means only half the work was done on the outstroke, the remaining half being performed on the return stroke. The cylinders were of the oscillating HYDRAULIC ENGINES. 333 type, and the valve A was formed solid with the gudgeon. The port B connects to the large side of the piston, and the port c to the small side. The port c is always open to the pressure supply D, while the port B is alternately open to the pressure supply D and exhaust pipe E. A small shock valve F was applied as shown to prevent the pressure in the Fig. 187. cylinder rising above that in the supply pipe, in case of any irregularity in the action of the valve. In all the types of engine we have described up to the present no attempt has been made to economise water when working a light load. Several more or less successful attempts have been made to produce an engine which shall consume pressure water in some proportion to the useful 334 HYDRAULIC POWER ENGINEERING. load. The best known of these engines is the revolving engine of Rigg. Fig. 1 88 shows a sectional elevation of Rigg's engine. The design consists essentially of three or four cylinders such as A B c arranged radially about a pin or gudgeon D. Each cylinder is fitted with a piston or ram EF G, which -is attached at its outer end to a revolving fly-wheel H by the Fig. 1 88. joints i K L. Now, if the axis of the fly-wheel coincides with the centre of the gudgeon D, it is evident that the cylinders and rams will be revolved about the gudgeon when the fly- wheel H is turned, but the rams will not make a reciprocat- ing stroke in the cylinders. If now the centre of the gudgeon D is moved off the axis of the wheel H, as shown in the figure, each ram on arriving at M will project some distance out of the piston, while at N the ram will recede into the HYDRAULIC ENGINES. r 335 piston. Thus in one complete revolution of the wheel H each ram will evidently make an out and return stroke, the length of this stroke being twice the eccentricity of the gudgeon D from the axis of the wheel H. If water pressure now be applied to each cylinder when at N, and the port opened to exhaust at M, the ram will be driven outwards, causing revo- lution of the wheel H and consequent revolution of the pistons and cylinders hence the name revolving engine. The quantity of water used is directly proportional to the length of piston stroke, and consequently to the eccentricity of the gudgeon D which corresponds to the crank-throw in an ordinary engine. By shifting the gudgeon D nearer to, or farther from, the axis of H, the power of the engine is varied and also the consumption of water. The pressure water enters through the ports o operated by a valve of the type shown in Fig. 180. The gudgeon D, which is subject to all the conditions of stress of an ordinary crank-pin, has to be capable of adjustment in position whilst the engine is run- ning. Fig. 189 shows the relay engine for controlling the gudgeon D. The gudgeon is securely attached to the two- ended ram P which passes into the cylinders Q R. By means of the internal plunger s the effective area of the ram P in the cylinder R is reduced to about half of its area in the cylinder Q. The cylinder R is always open to the pressure supply, while the cylinder Q is capable of communication to the pressure supply or exhaust by means of two small valves at T operated by a centrifugal governor not shown in the figure. When the engine is running below its normal speed as in starting, or if overloaded, the governor operates a valve which allows the water in the cylinder Q to escape to exhaust, thus allowing the eccentricity of the gudgeon D to be increased, and consequently the power of the engine augmented. When the power of the engine is abreast of the load the governor will have acquired its normal position and closed the exhaust valve, thus locking the ram P in its new position. 336 HYDRAULIC POWER ENGINEERING. If the load, or some part of it, be now removed, the engine will revolve quicker, thus causing the centrifugal governor to operate a valve connecting the cylinder Q to the cylinder R, and owing to the larger area of the ram p in the cylinder Q, the ram p will travel into the cylinder R, causing less eccen- tricity of the gudgeon D. When the speed of the engine again becomes normal the valve will be closed and the Fig. 189. motion of the plunger p arrested. Thus the water con- sumption is automatically controlled according to the load applied to the engine. There have been several attempts to attain this end, notably that of Hastie, who arranged for the crank-throw of an engine to be altered automatically by the variable turning moment required in the crank-shaft to overcome the load. A pair of hydraulic cylinders were arranged with plungers and HYDRAULIC ENGINES. 337 pitch chain connections to the crank-shaft, so that the load caused the chains to be partly wound round the shaft, thus driving the plungers back into their cylinders against the pressure water. The shaft was of cam form at the parts where the chains operated, so that at some point the turning moment required to overcome the load balanced the water pressure in the cylinders. This apparatus governed the crank throw of the engine, thereby producing economy of pressure water. The arrangement^ though ingenious, has now dropped out of use. The efficiency of hydraulic engines varies from about 50 to 80 per cent. For well-designed engines of the types illustrated, and working with a pressure of 700 Ibs. per square inch and upwards, an efficiency of 70 to 80 per cent, may be expected. The horse-power is then given by the equation RR= _ML R;/xC 33000 in which / = pressure in pounds per square inch. A = area of piston in square inches. L = stroke in feet. R = revolutions per minute. n = number of single-acting cylinders. C = efficiency -.70 to .80. CHAPTER XXIV. RECENT ACHIEVEMENTS. Hydraulic Lifts. Probably the most powerful com- bination of hydraulic lifts is that employed in connection with the hydraulic dock at the Union Iron Works, San Francisco, which is capable of raising a ship of 4,000 tons weight a height of 32 feet. Eighteen hydraulic rams are 'arranged on each side of the dock, which consists of a platform built of cross and longitudinal steel girders 62 feet wide, 440 feet long, provided with keel and sliding bilge blocks for the ship to rest upon. A set of four single- acting hydraulic plunger pumps 3^ inches diameter and 36-inch stroke, working at forty double strokes per minute, transmit water at a pressure of 1,100 Ibs. per square inch to the thirty-six hydraulic rams, each of 30 inches diameter, with a stroke of 16 feet. On the top of each hydraulic ram is a 6-foot pulley over which eight steel cables 2 inches in diameter pass, one end of each cable being anchored to the bed plates supporting the cylinders, while the other is secured to the side girders of the platform. The illustra- tion of the dock in Fig. 190 is from Gassier 's Magazine, and shows a vessel in position on the platform. When a ship is being lifted it sometimes happens that the load is not evenly distributed on the platform. Some rams, therefore, may carry a full load, while others are much underloaded. The platform is kept level by means of specially designed valve gear operated by the moving rams in such a manner that when one ram has a light load it moves ahead of the others, but in doing so lifts a lever and closes its inlet valve, so that the rams are practically stopping and ( UNIVERSITY j RECENT ACHIEVEMENTS. 339 starting dependent upon the load which may come upon them, the valves being opened and closed automatically by the movement of each of the rams. The valve box is secured on the ram itself and moves up and down with it, the inlet and outlet pipes working through stuffing boxes in the usual manner. The application of hydraulic power for effecting the open- ing of the bascules of the Tower Bridge over the Thames at London is shown in Figs. 191, 192, 193, and 194. On each of the outside main moving girders quadrants are arranged having toothed racks bolted thereon. Two racks are placed on each quadrant, the pitch being 5.9 inches, and pinions mounted on two shafts across the bridge gearing to these quadrants. The lower shaft with its pinion is driven from the east end of the pier, and the upper one from the west on the south pier, while on the north pier the lower shaft is driven from the west, and the upper one from the east end. These pinions are actuated from gearing having a ratio of 6 to i by hydraulic engines placed in chambers at the ends of the piers, the machinery at each end of each pier being sufficient for the full require- ments of one bascule, that at the other end of the pier being in reserve. Each set of machinery consists of two three-cylinder hydraulic engines of unequal power, having pinions on their crank-shafts which gear into spur-wheels on an inter- mediate shaft, a pinion on which gears into the spur-wheel on the end of the rack pinion shaft. The hydraulic engines were made of unequal power as a provision against the effect of wind on the large exposed surfaces of the bascules. It has been found, however, that it is not necessary to use more power than that given by one small engine. The engines have three plungers 8J inches diameter, 27-inch stroke in the large engines, and 7^ inches diameter and 24-inch stroke in the small engines. Each cylinder is provided with a separate working valve, separate spindles RECENT ACHIEVEMENTS. 34! being employed for the admission of pressure and the release of exhaust water. On the crank-shaft of each engine there is a brake wheel against which brake blocks attached to levers are thrust. The blocks are kept apart by hydraulic cylinders, and rams placed between the levers. They are drawn together by wire ropes and counter-weights when the bascules are s landing. Before starting the bas- cules, pressure is admitted to the cylinders by releasing the brakes. In ordinary working each bascule is raised and lowered by one hydraulic engine, the other three engines being in gear and running idle, the water circulating through their cylinders and valves. This provision is arranged in order that the power may be varied or the engine changed by the driver without having to leave his cabin. Clutches are provided by which any of the hydraulic engines can be thrown entirely out of gear. The time occupied in raising and lowering the bascule is about ij minutes. At each end of each pier an accumulator is provided with a ram 22 inches in diameter and an 1 8-foot stroke. In the machinery chambers other hydraulic pumps are provided for delivering water to the top cf the main towers for fire and domestic use. Provision is made for two hydraulic hoists having cradles 14 feet 9 inches long, 6 feet 6 inches wide, n feet high, the length of the lift being about no feet, for taking passengers to and from the high- level footways while the bascules are raised. The cradles are lifted and lowered by wire ropes from vertical cylinders, and rams placed in duplicate in the towers, safety gear being provided for gripping the guides and supporting the cradles in case of failure. Inter-locking gear is also arranged upon the cradles to prevent the hoist being started until both inside and outside doors are closed, or to prevent the doors being opened until the proper platform is reached and the hoist stopped. The hydraulic power for the bridge is generated by two '^B: . / RECENT ACHIEVEMENTS. 343 double tandem compound surface condensing engines, each of 360 I.H.P., the cylinders being 19! and 37 inches diameters respectively, while the pumps are yf inches diameter and 38-inch stroke. One engine is sufficient to provide power for the bridge, while the other is held in reserve. The water pressure is 700 Ibs. per square inch. The engines are supplied with steam by four Lancashire boilers, 7 feet 6 inches diameter, 30 feet long, working at 85 Ibs. pressure. In addition to the four accumulators in the piers, there are at the engine-house two accumulators with rams 20 inches diameter having a stroke of 35 feet. The pressure pipes are arranged in duplicate, while the return water pipes are single. The mains are protected from frost by hot-water pipes running alongside them, although a mixture of glycerine and water is employed in connection with the cylinders for the working of the bas- cules forming a small system of its own. Duplicate pumps actuated by hydraulic pressure placed within the south pier supply this subsidiary system. The machinery was designed by Sir W. G. Armstrong & Company in conjunction with and under the direction of Sir J. Wolfe Barry. It has been found by experience that the time required for the bridge to be opened for the passage of vessels at any particular period is so short that it is found unnecessary to use the lifts for conveying passengers from the lower to the higher level. Pedestrians who wish to ascend to the upper footway can do so by means of 205 steps arranged within the towers. The two bascules each weigh 1,070 tons, and they are carried on live ring rollers. Water Balance Railways. The author has intro- duced hydraulic brakes for controlling the motion of cars on cliff or inclined railways, using in connection with the water-balance system brakes which press against the rams under the influence of hydraulic pressure exerted through RECENT ACHIEVEMENTS. 345 rams working in cylinders fed by pumps driven directly from one of the axles of the cars. Fig. 195 is an elevation of such a railway, similar to those constructed and erected by the author in various parts of the country; and Fig. 196 is a sectional elevation of the hydraulic rail-gripping brakes in use upon such cars. The system of working in connection with these railways is to employ water in the form of ballast, which is introduced into the car w r hen at the upper platform to overbalance the weight of the loaded car standing at the low r er platform, and on the arrival of the water-ballasted car at the lower platform it discharges its water into a tank arranged there, from which .-:0.f ia n3T HTrr^H >-til iHRflHI^ SlJba Fig. 196. tank the water is again pumped back to a tank at the upper station, so as to enable the same water to be used over and over again. The tanks are arranged between the girders or framework of the cars, and made of a capacity such as will contain water sufficient to overbalance the bottom car when fully loaded and the upper car having no passengers therein. The advantages of employing hydraulic balance as against hauling by direct driving of the top rope pulley is that the weight of the water introduced is regulated to suit the number of passengers to be carried, the conductor at the 346 HYDRAULIC POWER ENGINEERING. lower station signalling to the brakesman at the top the number of passengers to be carried before the upper car is fully charged with water. It frequently happens that it is unnecessary to employ any water as ballast, owing to the preponderance of passengers for the down over those travel- ling on the up journey. Hydraulic buffers are arranged at the lower platform, so that on the car striking one pair the water or liquid is driven out through a contracted passage into the cylinders of the opposite pair, thus forcing out the rams of the buffers ready for the journey of the next car down. The arrangement of the hydraulic brakes for gripping the rails is shown in Fig. 196. The water or fluid under pres- sure acts behind rams which force outwards the slippers against the rail heads, the rail slippers being shaped to suit the head of the rail, and to thus grip it on the under side of the head, and prevent the car from mounting should any unforeseen contingency arise. A general arrangement of a cliff railway is shown in Fig. 197, one car being on the downward journey, the other in a correspondingly higher position on the other upward track, above the two bridges shown in the illustration, which is a photograph of the Lynton and Lynmouth Cliff Railway, which was constructed under the author's direction. Glasgow Harbour Tunnel Lifts. The hydraulic elevators employed in connection with the Glasgow Harbour Tunnel are more powerful than any yet constructed for a similar purpose, though the height of the lift is not so great as at the Eiffel Tower. The load at Glasgow on each cage is 12,000 Ibs., and the maximum lift 72 feet. The Eiffel Tower lift was for 72 persons, and the height 420 feet. There are six elevators in each shaft, three for raising and three for lowering vehicles. Fig. 198 illustrates three of the multiplying cylinders, and Fig. 199 shows the position of the car and the cylinders in the shaft. The diameter of the Fig. 197. CLIFF RAILWAY AT LYNTON. [To face p. 346. RECENT ACHIEVEMENTS. 347 elevating cylinders is 13 inches, the lowering cylinders being 1 1 \ inches diameter. The stroke of the rams in the cylinders is one-sixth of the car travel, the gearing being by three tandem sheaves, as shown in Fig. 198. The cylinders were tested to a pressure of 1,800 Ibs. per square inch, the work- ing pressure from the accumulators being 750 Ibs. per square inch. The piston is 30 inches long, and the ram is 10 inches in diameter of cast iron ; the piston, stuffing boxes, and gland being all of bronze. The ram is ij inches thick, and through the centre a 3-inch steel rod attached above the piston and passing through the head is arranged so as to rigidly connect the travelling sheave with the piston. The sheaves are respec- tively 52, 56, and 60 inches diameter. Four steel lifting ropes are employed, the ends being attached to adjustment rods, two ropes passing down to each side of the cage. Each rope is |- inch diameter, and is composed of six strands of steel wire wound round a hemp core, the strand itself consisting of eighteen wires, and each rope is tested up to 24 tons. The main valves are bolted directly to the cylinder head. Each valve is 3 inches diameter, and has openings so graduated that the retarding or accelerating effort of the water when closing or opening the valve is constant. The levers from the operating gallery are connected with the pilot valve, which controls the operation of the main valve, so that the travel of the pilot valve lever is only slight in relation to the main valve. The main valve works on the differential principle, the area above being double that below the valve piston. The pressure is constantly below the valve piston, and the valve is moved down by admitting the pres- sure above the piston causing the valve to descend. The valve rises if communication is opened between the top of the valve cylinder and the discharge tank. The lifting cylinders are arranged so that there is a pre- ponderance of weight on the car side with pressure being 3^ LIBR>4^p or THK UNIVERSITY Fig/198- RECENT ACHIEVEMENTS. 349 admitted above the piston to lift the load, or communication is established from above the piston to the discharge tank to lower the load. Water is consumed proportional to the load lifted, there being two powers. For load of 6,000 Ibs. or less the cylinders use 37.8 gallons when lifting the load 74 feet, while for a greater load than 6,000 Ibs., 70.7 gallons are consumed for the same travel. This change of power is rendered automatic by the use of a valve which remains closed with a load of less than 6,000 Ibs., so that the water beneath the main piston lifts a balance check valve and is forced into a pipe connected with the main cylinder head. When lowering the car, however, this balance check valve closes and an unbalanced check valve lifts, thus opening communication from below the piston to the discharge tank. An amount of water equal in volume to the space beneath the piston is drawn in below the piston, and on the reverse stroke when lifting this water is introduced above the piston, so that the actual quantity of water used is that due to the displacement of the plunger only. When lifting loads above 6,000 Ibs. the preponderance of effort is below the piston of the automatic valve which rises and opens communication between the valve and the discharge tank. The lowering cylinders are arranged so that the weight of the car is overbalanced and the tendency of the unloaded car would be to rise, but when loaded to descend thus using no water, the water in this case serving only as a brake. Should a vehicle be too light to overcome the overbalance and friction of the machine, water pressure is introduced into the cylinders. Triple grip safety catches are fitted beneath each car arranged on the Otis Company's system, this Company having carried out and constructed the elevators. Hydraulic Forging" Press. Fig. 200 is an illustration of a 4,ooo-ton hydraulic forging press in use at the works 35O HYDRAULIC POWER ENGINEERING. RECENT ACHIEVEMENTS. 351 of Messrs Charles Cammell & Co. Ltd., Sheffield. This press, although not being by any means the largest of its kind in Sheffield, is probably one of the best examples of the heavy forging press now so generally adopted for dealing with massive forgings. Presses of over 10,000 tons power are working in the most satisfactory manner upon blocks of metal totally beyond the power of any steam hammer. In the 4,ooo-ton Davy Press illustrated, which is from a photograph of Messrs Cammell's forge, two main rams of 36 inches diameter are mounted in the upper frame casting 9 feet 3 inches apart at the centres. Two lifting rams are also arranged thereon each of 9 inches diameter, the stroke of the press being 7 feet. The four columns carrying the head are of steel 20 inches diameter, the centres of the same being 15 feet in one direction, and 6 feet 4 inches in the other. The distance between head and block is 21 feet. The press is supplied with water at 4,500 Ibs. per square inch pressure, by means of three single-acting pump plungers, each 6 inches diameter and 1 2-inch stroke, driven from the crank-shaft of a pair of steam engines having cylinders of 34 inches diameter. The supply water to the pumps is fed from a low-pressure main at 60 Ibs. pressure, this low pressure being also useful in filling the main cylinders when the smaller or lifting rams are working, raising the crosshead and tool. This arrangement for supplying pressure water to the pump barrels admits of small valves being fitted to the pumps. The pumps work at varying speeds up to sixty or more revolutions per minute, the speed of lifting when the low- pressure water is introduced into the main cylinders and the high pressure to the lifting cylinders being 8 inches per revolution, while the speed of descent under the full load is J inch per revolution, the relative areas of the lift- ing and lowering rams being 16 to i. Two levers control the whole movements of the press, one of these being also for starting the pumps. In operation the forging tool is 352 HYDRAULIC POWER ENGINEERING. raised 2 feet per second, this quick motion being necessary to admit of moving the forging readily while hot. The employment of the forging press admits of a much lower building being constructed than would be possible with a steam hammer. This advantage also enables cranes to travel over the entire press, and thus to command the whole forge area. The two travellers shown in Messrs Cammell's forge are respectively of 150 and no tons lifting power. Niagara Power The amount of water power flowing to waste, so far as mechanical energy is concerned, in various parts of the world, is truly appalling in its immensity. The installations, however, at Tivoli (by means of which power developed there is transmitted to Rome, 16 miles distant), at Geneva, SchafThausen, Zurich, Telluride (in Colorado), and other places, are amply sufficient to warrant the asser tion that the trend of commercial utilisation of such water aste is becoming a factor for profitable consideration wherever mechanical power of any kind for any purpose is required. The flow of water at the crest of the Horse Shoe Falls at Niagara has been found to be about 275,000 cubic feet per second, and it has been estimated that over 100,000,000 tons per hour pass over the Fall. The plunge of this immense mass of water from one level to another of 165 feet has enabled the Fall to be harnessed, and energy taken therefrom by the Niagara Falls Power Company. The theoretical horse-power which is available at the Falls has been given by the United States Government engineers as 6,750,000 H.P., an amount which, if produced by steam, would necessitate the consumption of more coal than is at present raised throughout the world. The illustration shown in Fig. 201, by kind permission of Messrs Gassier, gives a bird's-eye view and section of the Niagara installation, from which it will be seen that water is taken from the upper level above the first Fall, and allowed OF THB UNIVERSITY "i I i Fig. 200. AOOO-TON HYDRAULIC Fc m PRESS (Cammell's Works, Sheffield). [ To face i>. OF THB UNIVERSITY RECENT ACHIEVEMENTS. 353 to pass through turbines mounted in a power house and wheel pit, the discharge or tail-race water from the turbines passing through the tunnel leading out into the lower level below the Falls. The wheel pit of the Niagara Falls Power Company is a long slot cut in the rock, instead of a group of small wheel pits, and the tail-race from each wheel or turbine is connected by a short curve to the main tail-race tunnel. The turbines are arranged, some for developing 1,100 H.P. per wheel, others 5,000 H.P. per wheel. The 1,100 H.P. turbines are of the Jonval type, the fall of water being 140 feet on to the wheels, which make 250 revolutions per minute. Various manufacturing establishments have already erected machinery on the ground near to the Niagara Falls installa- tion. But beyond the mere local uses for the power, and the enormous development of industries which must attend this form of producing mechanical energy from one centre, other applications are being made for transmitting the power to a distance, for the purpose of displacing private plants at present employed for electric lighting and for ordinary manu- facturing purposes. Seeing that the transmission of oil by means of a pipe line a distance of over 400 miles, and also the transmission of natural gas by a pipe line a distance of 120 miles, have been found feasible, it is not too much to expect that ere long there will be distributed mechanical power to similar distances, and with results which will be not only economical but advantageous alike to the users and the districts where it is employed, by reason of its displacing private steam or other power-generating motors and leaving the atmosphere free from the products of combustion necessarily attendant upon the use of coal for such power-producing purposes. Turbine for Small Fall. As an example of what is possible under difficult and unpromising conditions, the Z 354 HYDRAULIC POWER ENGINEERING. turbine installed at Strensham Mills, near Worcester, is worthy of notice. Owing to the natural conditions of the River Avon the water head available varies from 4 feet in summer, with a diminished supply, to 2 feet in winter, with an excessive supply. The horse power required was 40, and it became neces- sary to design a turbine adapted to the varying conditions. A Jonval turbine was selected, having a double ring of vanes. The outer ring of vanes is sufficient to supply the power under a 3 foot head, and as the head is diminished by flood, the gates closing the inner ring of guide passages are opened to allow a larger quantity of water to pass. The method of using two rings of vanes allows scope in designing, as the outer vanes can be speeded for correct working under a 3 foot head, and the inner for correct working under a 2 foot head. The turbine is 13 ft. 2 in. in diameter, and makes 14 revolutions per minute. APPENDIX. TABLE XII. PRESSURE OF WATER.* Showing pressure of water in pounds per square inch for every foot in height to 270 feet. By this Table, from the pounds pressure per square inch the feet head is readily obtained, and vice versa. i V *>! 1 u T3 s .i -6 S 43 ^} .5 1 43 *? 1 ll L M $ s ffi $ a % c3 M is ffi u] rt B i 15 ' I cu 3 OJ II aj D tj 1 1 II I 'iJ s *-& = - 2 i 1|| V is i "rt ** 1 1 oi "'S, i j 'o-' c S ol S 5: ^ rt 8 f/: ^ rt V * p^ S j 5 S * 5 5 * fi i .0122 .0005 7! 47- I 7 2.037 I9 , 291.0 12.571 .0490 .0021 8 50.26 2.171 193 298.6 12.900 1 .1104 .0047 81 53-45 2.309 19 * 306.3 13.232 i .1963 .3068 .4417 .6013 7854 .9940 .0084 .0132 .0259 0339 .0429 84 8f 56.74 60.13 63.61 67.20 70.88 74.66 2.451 2-597 2-747 2.903 3.062 3-225 20 20* 21 24 22 330.0 346.3 363-0 380.1 397-6 13-569 14-256 14.960 15.681 16.420 17.176 j i 1.227 OSS 10 78.54 3-393 2 3 415-4 17-945 T s 1.484 .0641 I0 1 82 51 2 3j 433-7 18.735 15 1.767 .0763 io 86.59 3-740 24 452.3 19-539 T f 2.073 .0895 loj 90.76 3.920 245 471.4 20.364 2.405 .1038 II 95-03 4.105 2 5 490.8 2I.2O2 I? 2.761 .1192 III 99.40 4.294 2 5& 510.7 22.O62 2 i 103.8 4.484 26 530-9 22-935 3-546 I53 1 "1 108.4 4.682 26.^ 55^-5 23-824 a I 3-976 4-430 .1717 12 113.0 117.8 4.881 5.088 2?A 572-5 593-9 24-732 25.656 4.908 .2120 I27T 122.7 5.300 28" 615-7 26.598 i 5-4II 5-939 2337 2565 12 J I3 I 127.6 132.7 5-5 12 5-732 28^ 29 637-9 660.5 27.567 28.533 3 34 6.491 7.068 7.669 .2804 .3053 33 T 3 I3l 137-8 I43-I 148.4 5-952 6.182 ' 6.410 29* 30 31 68<. 4 706 8 754-8 29.522 30-533 32.607 3 8.295 8.946 .3583 3864 153-9 J59-4 6.649 6.886 32 33 804.2 855-3 34-741 36.949 34 9.621 .4156 Ill 165.1 7-132 34 907.9 39.221 3f 10.32 .4458 Ml 170.8 7.388 35 962.1 41.562 3J 11.04 .4769 i5 t 176.7 7-633 36 1017.9 43-973 3* 4 11.79 12.56 .5193 182.6 188.6 7.888 8.147 37 38 1075.2 1134.1 46.448 48.993 4i 14.18 .6125 15! 194.8 8.415 39 1194.6 51.607 ? 15.90 17.72 19.63 .6868 7655 .8480 16 i6i i64 201.0 207.3 213.8 8.683 8-955 9.236 40 4 2 1256.6 1320.3 1385-4 54-259 57- 37 59.849 sl 53 21.54 23-75 9348 1.026 i6| 220.3 226.9 9.516 9.802 43 44 1452.2 1520.5 62.735 65.686 25.96 1. 121 233-7 10.095 45 1590.4 63.688 6 4 28.27 1. 221 240.5 10.389 46 1661.9 7 I -794 6i 30.67 L325 247.4 10.687 47 1734-9 74.948 6* 6| 33-i8 35-78 1-433 I -545 18 254-4 261.5 10.990 11.297 48 49 1809.6 1885.7 78.175 81.462 7 38.48 1.662 Ite 268.8 ii. 612 50 1963-5 84.801 7i 41.28 1-783 i8| 276.1 11.927 7* 44.17 1.908 19 283.5 12.247 The Worthington Pumping Engine Company point out that in estimating the capacity of Worthington Pumps (i.e., the delivery in gallons per minute or per hour) a' a given rate of piston speed, it should be noted that the Worthington Pump has two double acting water plungers ; its capacity, therefore, being double that of any ordinary double-acting pump of same size.or four times as large as a single-acting pump. INDEX. A CCUMULATORS, 197- r\ 207 Archimedes, principle of, 1 1 Areas and displacements in pump action, 356 Armstrong valve, 121 Axial flow turbines, 275 BALANCED lifts, 151 Baling press, 224 Barometric column, 12 Bars for presses, 220 Bear punching, 230 Belt power pump, 251 Bolts, maximum loadings for, 85 - for flanges, 95 Brakes, hydraulic, 345 Brarnah, 211 Breast wheel, 317 Bridge machinery, 341 Brindley's valve, 127 Bucket and plunger pump, 253 Buffers, 346 /^AMMELL'S forging press, ^ 349 Capstan, 331 Cars and cages, 140 Cast iron, 40 Cast-iron cylinders, 41, 58 - pipes, 86 Casting, 60, 63 Chain lifts, 155 Circular flanges, 87 of cast-iron pipes, dimensions of, 96 Cliff railways, 345 Clips for lifts, 161 Coefficients of efficiency, 169-170 Compensating balance, 151 Conditions for lifts, 135 Controlling valves, 1 1 1 Copper coating rams, 47 Cotton press, 212 - density, 212 Cranes, 177 Cylinders, cast-iron, 58 - steel, 59 - thickness of, 57, 58, 59 DAVY press, 351 Density of water, 5 - of cotton, 212 Designing lifts, 159 turbines, 299 Direct acting pumps, 254 acting lifts, 173 - puller, 187 358 INDEX. Double-acting pumps, 253, 258 Duckham weigher, 188 Dumping press, 226 EFFICIENCY of jacks, 178 J ' - of balanced lifts, 1 5 1 - of hydraulic motors, 337 - of lifts, 173 Elasticity, limit of, 48 Elevators, Otis, 159, 163, 347 Energy of water, 15 Engines, hydraulic, 319 - pumping, 254 Equal pressure, 7 Extension of metals, 47 FALLS of Niagara, 352 - utilised, 353 Flow of water, 21 Forging press, 235, 349 - Cammell & Co.'s, 350 Foundry cranes, 184 Friction of leathers, 73 GIRARD turbine, 265 Glasgow subway lifts, 347 Grooved pulleys, 167 Gun-metal castings, 46 HAMILTON tables, 22 Hand-power pumps, 247 punch, 230 Head of water, 355 Hemp packing, 80 SMITH'S Hick's formula, 73 High pressure, 37 Hook's law, 48 Hydraulic accumulators, 197 cranes, 177 engines, 319 - intensifies, 206 - lifts, 131 - mains, 97 - packings, 67 - pipe joints, 85 - presses, 229 - ram, 17 - valves, 1 1 1 Hydrostatics, 6 T MPULSE turbines, 271 * Intensifies, 206 Inward flow, 265 JACKS, hydraulic, 177 Jigger, 191 Joints, flanged, 98 - for sliding surfaces, 74, 101 - of pipes, 86, 101 - leather, 67 - swivelling, 104, 107 LEATHER packings, 67 Lifting machinery, 131 Lifts, hydraulic dock, at San Francisco, 338 Glasgow Harbour Tunnel, 348 - Otis, 159, 163, 347 - direct-acting, or ram, 133 - suspended, 157, 191, 347 Tower Bridge, 340 INDEX. 359 Loads, test, 51 Low pressures, 36 Lynton Cliff Railway, 346 MALLEABLE cast iron, 46 Materials, 45 Maximum strains, 54 Meacock's valve, 125 Measuring flow of water, 21 Medium pressure, 36 Multiple povver lift, 157, 159, 191 N l UTS for press bars, 219 /DESERVED flow of water, Oil press, 227 Orifices, wheel, 22 Otis lifts, elevators, 159, 163, 347 Outward flow turbine, 275 Overshot wheel, 315 PACKINGS, 67, 85 Pascal's theory, 6 Pelton wheel, 267-279 Phosphor bronze, 47 Pipe joints, 86 Pipes, 102 Piston value, 118 Platform lift, 132 Portable riveters, 241 Potential energy, 15 Presses, 229 for baling, presses of platten to bale in, 212 - wrought-iron bars for, 220 Pressure of water, 355 Pressures, 36 Principles of equal pressure, 6 - of hydraulics, 3 Properties of water, I Puller, direct, 187 Pulleys, 167 Pumps, 213, 247 - action of, diameters, areas, and displacements, 356 Punching bear, 230 RAIL-GRIPPING brake, 345 Ram lifts, 133 Reaction of flowing water, 19 - turbines, 280 Recent achievements, 338 Regulator, 301 Rigg engines, 334 Riveters, 239 Ropes, wheel, 166 - wire, 165, 169 SAFE loads, 52 Safety wedges, 161 Salt water, 6 Shock valves, 1 1 5 Slide valves, 117, 121 Sliding surfaces, 68 Square orifices, 23 Steady loads, 52 Steam pumps, 254 Steel cylinders, 59 360 INDEX. Steel rope, 168, 169 - breaking weight of, 165 Stop valves, 112, 114 Strensham Mills, turbine at, 353 Stresses in machines, 54 Suspended lifts, 156 Swivelling joints, 104 T EST loads, 51 Theoretical efficiency lifts, Tower Bridge machinery, 340 Turbines, 263, 314, 353 Tweddell's riveter, 239 u LEATHERS, 75 Undershot wheels, 318 V ALVE, piston, 118 shock, 115 Valve, stop, 112, 114 Valves, controlling, 1 1 1 - slide, 117, 121 Velocity of water, 28, 31, 39 - due to head, 13 WAREHOUSE cranes, 192 Water balance railways, 343 - properties of, I - wheels, 315 Waterfalls, utilisation of, 352 Weight of cotton, 212 of water, 6 Wharf cranes, 193 Wheel press, 238 Wheels for ropes or chains, 167 Wire ropes, 165, 169 Workshop cranes, 1 8 1 Worthington pumps, 255 Wrought-iron bars, 220 Printed at THE DARIEN PRESS, Edinburgh, j, STATIONERS' HALL COURT, LONDON, E.G. January, 1901. CROSBY LOCKWOOD & SON'S Catalogue of Scientific, Technical and Industrial Books. MECHANICAL ENGINEERING CIVIL ENGINEERING . . . MARINE ENGINEERING. AC- MINING & METALLURGY COLLIERY WORKING, &c- ELECTRICITY 23 ARCHITECTURE & BUILDING . 25 SANITATION & WATER SUPPLY 27 PAGE 1 10 17 19 21 PAQE CARPENTRY & TIMBER ... 28 DECORATIVE ARTS 80 NATURAL SCIENCE 82 CHEMICAL MANUFACTURES . 84 INDUSTRIAL ARTS 86 COMMERCE, TABLES. &c. . . 41 AGRICULTURE & GARDENING- 48 AUCTIONEERING. VALUING. &c. 48 LAW & MISCELLANEOUS. . . 47 MECHANICAL ENGINEERING, &c. THE MECHANICAL ENGINEER'S POCKET-BOOK. Comprising Tables, Formulae, Rules, and Data : A Handy Book of Reference for Daily Use in Engineering Practice. By D. KINNEAR CLARK, M. Inst. C.E., Fourth Edition. Small 8vo, 700 pp., bound in flexible Leather Cover, rounded corners 6/O SUMMARY OF CONTENTS: MATHEMATICAL TABLES. MEASUREMENT OF SUR- FACES AND SOLIDS. ENGLISH AND FOREIGN WEIGHTS AND MEASURES. MONEYS. SPECIFIC GRAVITY, WEIGHT, AND VOLUME. MANUFACTURED METALS. STEEL PIPES BOLTS AND NUTS. SUNDRY ARTICLES IN WROUGHT AND CAST IRON, COPPER BRASS, LEAD, TIN, ZINC. STRENGTH OF TIMBER. STRENGTH OF CAST IRON. STRENGTH OF WROUGHT IRON. STRENGTH OF STEEL. TENSILE STRENGTH OF COPPER, LEAD, &c. RESISTANCE OF STONES AND OTHER BUILDING MATERIALS. RIVETED JOINTS IN BOILER PLATES. BOILER SHELLS. WIRE ROPES AND HEMP ROPES. CHAINS AND CHAIN CABLES. FRAMING. HARDNESS OF METALS, ALLOYS, AND STONES. LABOUR OF ANIMALS. MECHANICAL PRINCIPLES. GRAVITY AND FALL OF BODIES. ACCELERATING AND RETARDING FORCES. MILL GEARING, SHAFTING, &c. TRANSMISSION OF MOTIVE POWER. HEAT. COMBUSTION: FUELS. WARMING, VENTI- LATION, COOKING STOVES. STEAM. STEAM ENGINES AND BOILERS. RAILWAYS. TRAMWAYS. STEAM SHIPS. PUMPING STEAM ENGINES AND PUMPS. COAL GAS, GAS ENGINES, &c. AIR IN MOTION. COMPRESSED AIR. HOT AIR ENGINES. WATER POWER. SPEED OF CUTTING TOOLS. COLOURS. ELECTRICAL ENGINEERING. " Mr. Clark manifests what is an innate perception of what is likely to be useful in a pocket- book, and he is really unrivalled in the art of condensation. It is very difficult to hit upon any mechanical engineering subject concerning which this work supplies no information, and the excellent index at the end adds to its utility. In one word, it is an exceedingly handy and efficient tool, possessed of which the engineer will be saved many a wearisome calculation, or yet more wearisome hunt through various text-books and treatises, and, as such, we can heartily recommend It to our readers." The Engineer. " It would be found difficult to compress more matter within a similar compass, or produce a book of 650 pages which should be more compact or convenient for pocket reference. ... \\ ill be appreciated by mechanical engineers of all classes." Practical Engineer L. A CROSBY LOCK WOOD & SON'S CATALOGUE. MR. MUTTON'S PRACTICAL HANDBOOKS. THE WORKS' MANAGER'S HANDBOOK. Comprising Modern Rules, Tables, and Data. For Engineers, Millwrights, and Boiler Makers ; Tool Makers, Machinists, and Metal Workers ; Iron and Brass Founders, &c. By W. S. MUTTON, Civil and Mechanical Engineer, Author of "The Practical Engineer's Handbook." Sixth Edition, carefully Revised, with Additions. In One handsome Volume, medium 8vo, strongly bound. [Just Published. 1 5/Q _ The Author haying compiled Rules and Data for his own use in a great variety of modern engineering work, and having found his notes extremely useful, decided to publish them revised to date believing that a practical work, suited to the DAILY REQUIREMENTS OF MODERN ENGINEERS, would be favourably received. " Of this edition we may repeat the appreciative remarks we made upon the first and third. Since the appearance of the latter very considerable modifications have been made, although the total number of pages remains almost the same. It is a very useful collection of rules, tables, and workshop and drawing office data." The Engineer, May 10, 1895. " The author treats every subject from the point of view of one who has collected workshop notes for application in workshop practice, rather than from the theoretical or literary aspect. The volume contains a great deal of that kind of information which is gained only by practical experience, and is seldom written in books." The Engineer, June 5, 1885. " The volume is an exceedingly useful one, brimful with engineer's notes, memoranda, and rules, and well worthy of being on every mechanical engineer's bookshelf." Mechanical World. " The information is precisely that likely to be required in practice. . . . The work forms a desirable addition to the library not only of the works' manager, but of any one connected with general engineering." Mining Journal. " Brimful of useful information, stated in a concise form, Mr. Hutton's books have met a pressing want among engineers. The book must prove extremely useful to every practical man possessing a copy." Practical Engineer. THE PRACTICAL ENGINEER'S HANDBOOK. Comprising a Treatise on Modern Engines and Boilers, Marine, Locomotive, and Stationary. And containing a large collection of Rules and Practical Data relating to Recent Practice in Designing and Constructing all kinds of Engines, Boilers, and other Engineering work. The whole constituting a com- prehensive Key to the Board of Trade and other Examinations for Certificates of Competency in Modern Mechanical Engineering. By WALTER S. HUTTON, Civil and Mechanical Engineer, Author of " The Works' Manager's Handbook for Engineers," &c. With upwards of 370 Illustrations. Fifth Edition, Revised with Additions. Medium 8vo, nearly 500 pp., strongly bound. [Just Published. 1 8/O BflF"~ This Work is designed as a companion Author's "WORKS' MANAGER'S HANDBOOK." It possesses many new and o fe atures, and con- tains, like its predecessor, a quantity of matter not originally ntended for publication, but collected by the A uthor for his own use in the c nstruc on of a great variety of MODERN ENGINEERING WORK. The information is given in a condensed and concise form, and is illustrated by upwards of 370 Woodcuts; and comprises a quantity of tabulated matter of great value to all engaged in designing, constructing, or estimating for ENGINES, BOILERS, and OTHER ENGINEERING WORK. "We have kept it at handler several weeks, referring to it as occasion arose, and we have not on a single occasion consulted its pages without finding the information of which we were in quest." Athenaunt. " A thoroughly good practical handbook, which no engineer can go through without learning something that will be of service to him." Marine Engineer. " An excellent book of reference for engineers, and a valuable text-book for students of engineering. " Scotsman . " This valuable manual embodies the results and experience of the leading authorities on mechanical engineering." Building News. " The author has collected together a surprising quantity of rules and practical data, and has shown much judgment in the selections he has made. . . . There is no doubt that this book is one of the most useful of its kind published, and will be a very popular compendium." Engineer. " A mass of information set down in simple language, and in such a form that it can be easily referred to at any time. The matter is uniformly good and well chosen, and is greatly elucidated by the illustrations. The book will find its way on to most engineers' shelves, where it will rank as one of the most useful books of reference." Practical Engineer " Full of useful information, and should be found on the office shelf of all practical engineers. English Mechanic. MECHANICAL ENGINEERING, &>c. MR. MUTTON'S PRACTICAL HANDBOOK8-conrtmd. STEAM BOILER CONSTRUCTION, A Practical Handbook for Engineers, Boiler-Makers, and Steam Users. Containing a large Collection of Rules and Data relating to Recent Practice in the Design, Construction, and Working of all Kinds of Stationary, Loco- motive, and Marine Steam-Boilers. By WALTER S. HUTTON, Civil and Mechanical Engineer, Author of "The Works' Manager's Handbook," "The Practical Engineer's Handbook," &c. With upwards of 500 Illustrations. Third Edition, Revised and much Enlarged, medium 8vo, cloth . . 1 8/O B9~* THIS WORK is issued in continuation of the Series of Handbooks written by the A uthor, viz. .-"THE WORKS' MANAGER'S HANDBOOK " and" THE PRACTICAL ENGINEER'S HANDBOOK," which are so highly appreciated by engineers for the practical nature of their information ; and is consequently written in the same style as those works. The Author believes that the concentration, in a convenient form for easy reference, of such a large amount of thoroughly practical, information on Steam- Boilers, will be of considerable service to those for whom it is intended, and he trusts the book may be deemed worthy of as favourable a reception as has been accorded to its predecessors. " One of the best, if not the best, books on boilers that has ever been published. The infor- mation is of the right kind, in a simple and accessible form. So far as generation is concerned, this is, undoubtedly, the standard book on steam practice." Electrical Review. " Every detail, both in boiler design and management, is clearly laid before the reader. The volume shows that boiler construction has been reduced to the condition of one of the most exact sciences ; and such a book is of the utmost value to the/?w de si'ecle Engineer and Works Manager.' Marine Engineer. " There has long been room for a modern handbook on steam boilers ; there is not that room now, because Mr. Hutton has filled it. It is a thoroughly practical book for those who are occupied in the construction, design, selection, or use of boilers." Engineer. " The book is of so important and comprehensive a character that it must find its way into the libraries of every one interested in boiler using or boiler manufacture if they wish to be thoroughly informed. We strongly recommend the book for the intrinsic value of its contents." Machinery Market. PRACTICAL MECHANICS' WORKSHOP COMPANION. Comprising a great variety of the most useful Rules and Formulae in Mechanical Science, with numerous Tables of Practical Data and Calculated Results for Facilitating Mechanical Operations. By WILLIAM TEMPLETON, Author of " The Engineer's Practical Assistant," &c., &c. Eighteenth Edition, Revised, Modernised, and considerably Enlarged by WALTER S. HUTTON, C.E., Author of "The Works' Manager's Handbook," "The Practical Engineer's Hand- book," &c. Fcap. 8vo, nearly 500 pp., with 8 Plates and upwards of 250 Illus- trative Diagrams, strongly bound for workshop or pocket wear and tear. 6/O " In its modernised form Mutton's ' Templeton ' should have a wide sale, for it contains much valuable information which the mechanic will often find of use, and not a few tables and notes which he might look for in vain in other works. This modernised edition will be appreciated by all who have learned to value the original editions of 'Templeton.'" English Mechanic. " It has met with great success in the engineering workshop, as we can testify ; and there are a great many men who, in a great measure, owe their rise in life to this little book." Building Nevis. " This familiar text-book well known to all mechanics and engineers is of essential service to the every-day requirements of engineers, millwrights, and the various trades connected with engineering and building. The new modernised edition is worth its weight in gold." Building News. (Second Notice.) " This well-known and largely-used book contains information, brought up to date, of the sort so useful to the foreman and draughtsman. So much fresh information has been introduced as to constitute it practically a new book. It will be largely used in the office and workshop." Mechanical World. " The publishers wisely entrusted the task of revision of this popular, valuable, and usefu book to Mr. Hutton, than whom a more competent man they could not have found." Iron. ENGINEER'S AND MILLWRIGHT'S ASSISTANT. A Collection of Useful Tables, Rules, and Data. By WILLIAM TEMPLETON. Eighth Edition, with Additions. i8mo, cloth ... . 2/6 "Occupies a foremost place among books of this kind. A more suitable present to an apprentice to any of the mechanical trades could not possibly be made." Building News. "A deservedly popular work. It should be in the 'drawer' of every mechanic." English Mechanic. 4 CROSBY LOCK WOOD & SON'S CATALOGUE. THE MECHANICAL ENGINEER'S REFERENCE BOOK. For Machine and Boiler Construction. In Two Parts. Part I. GENERAL ENGINEERING DATA. Part II. BOILER CONSTRUCTION. With 51 Plates and numerous Illustrations. By NELSON FOLEY, M.I.N.A. Second Edition, Revised throughout and much Enlarged. Folio, half-bound, net . 3 3s. PART I. MEASURES. CIRCUMFERENCES AND AREAS, &c., SQUARES, CUBES FOURTH POWERS. SQUARE AND CUBE ROOTS. SURFACE OF TUBES. RECIPROCALS. LOGARITHMS. MENSURATION. SPECIFIC GRAVITIES AND WEIGHTS. WORK AND POWER. HEAT. COMBUSTION. EXPANSION AND CONTRACTION. EXPANSION OF GASES. STEAM. STATIC FORCES. GRAVITATION AND ATTRACTION. MOTION AND COMPUTATION OF RESULTING FORCES. ACCUMULATED WORK. CENTRE AND RADIUS OF GYRATION. MOMENT OF INERTIA. CENTRE OF OSCILLATION. ELECTRICITY. STRENGTH OF MATERIALS. ELASTICITY. TEST SHEETS OF METALS. FRICTION. TRANSMISSION OF POWER. FLOW OF LIQUIDS. FLOW OF GASES. AIR PUMPS, SURFACE CONDENSERS, &c. SPEED OF STEAMSHIPS. PROPELLERS. CUTTING TOOLS. FLANGES. COPPER SHEETS AND TUBES. SCREWS, NUTS, BOLT HEADS, &c. VARIOUS RECIPES AND MISCELLANEOUS MATTER. WITH DIAGRAMS FOR VALVE-GEAR, BELTING AND ROPES, DISCHARGE AND SUCTION PIPES, SCREW PROPELLERS, AND COPPER PIPES. PART II. TREATING OF POWER OF BOILERS. USEFUL RATIOS. NOTES ON CONSTRUCTION. CYLINDRICAL BOILER SHELLS. CIRCULAR FURNACES. FLAT PLATES. STAYS. GIRDERS. SCREWS. HYDRAULIC TESTS. RIVETING. BOILER SETTING, CHIMNEYS, AND MOUNTINGS. FUELS, &c. EXAMPLES OF BOILERS AND SPEEDS OF STEAMSHIPS. NOMINAL AND NORMAL HORSE POWER. WITH DIAGRAMS FOR ALL BOILER CALCULATIONS AND DRAWINGS OF MANY VARIETIES OF BOILERS. "The book is one which every mechanical engineer may, with advantage to himself, add to his library." industries. " Mr. Foley is well fitted to compile such a work. . . . The diagrams are a great feature of the work. . . . Regarding the whole work, it may be very fairly stated that Mr. Foley has produced a volume which will undoubtedly fulfil the desire of the author and become indispensable to all mechanical engineers." Marine Engineer. " We have carefully examined this work, and pronounce it a most excellent reference book for the use of marine engineers." Journal of American Society of Naval Engineers. COAL AND SPEED TABLES. A Pocket Book for Engineers and Steam Users. By NELSON FOLEY, Author of " The Mechanical Engineer's Reference Book." Pocket-size, cloth . 3/6 " These tables are designed to meet the requirements of every-day use ; are of sufficient scope for most practical purposes, and may be commended to engineers and users of steam." Iron. TEXT-BOOK ON THE STEAM ENGINE. With a Supplement on GAS ENGINES, and PART II. on HEAT ENGINES. By T. M. GOODEVE, M.A., Barrister-at-Law, Professor of Mechanics at the Royal College of Science, London ; Author of " The Principles of Mechanics," " The Elements of Mechanism," &c. Fourteenth Edition. Crown 8vo, cloth . 6/O " Professor Goodeve has given us a treatise on the steam engine which will bear comparison with anything written by Huxley or Maxwell, and we can award it no higher praise." Engineer. " Mr. Goodeve's text-book is a work of which every young engineer should possess himself." ^fining Journal. ON GAS ENGINES. With Appendix describing a Recent Engine with Tube Igniter. By T. M. GOODEVE, M.A. Crown 8vo, cloth 2/6 " Like all Mr. Goodeve's writings, the present is no exception in point of general excellence. It is a valuable little volume." Mechanical World. A TREATISE ON STEAM BOILERS. Their Strength, Construction, and Economical Working. By R. WILSON, C.E. Fifth Edition. i2mo, cloth 6/O " The best treatise that has ever been published on steam boilers. Engineer. "The author shows himself perfect master of his subject, and we heartily recommend all employing steam power to possess themselves of the work." Rylancfs Iron Trade Circular. THE MECHANICAL ENGINEER'S COMPANION of Areas, Circumferences, Decimal Equivalents, in inches and feet, millimetres squares, cubes, roots, &c. ; Weights, Measures, and other Data. Also Prac- tical Rules for Modern Engine Proportions. By R. EDWARDS, M.Inst.C.E. Fcap. 8vo, cloth. [Just Published. 3/6 " A very useful little volume. It contains many tables, classified data and memoranda, eneraliy useful to engineers." Engineer. i his small book is what it professes to be, viz. : ' a handy office companion,' giving as it does, in a succinct form, a variety of information likely to be required by mechanical engineers in their everyday office work." Nature. MECHANICAL ENGINEERING, &>c. A HANDBOOK ON THE STEAM ENGINE. With especial Reference to Small and Medium-sized Engines. For the Use of Engine Makers, Mechanical Draughtsmen, Engineering Students, and users of Steam Power. By HERMAN HAEDER, C.E. Translated from the German with considerable additions and alterations, by H. H. P. POWLES, A.M.I.C.E., M.I.M.E. Second Edition, Revised. With nearly 1,100 Illustrations. Crown 8vo, cloth 9/O "A perfect encyclopaedia of the steam engine and its details, and one which must take a per- manent place in English drawing-offices and workshops." A Foreman Pattern-maker. "This is an excellent book, and should be in the hands of all who are interested in the con- struction and design of medium-sized stationary engines. ... A careful study of its contents and the arrangement of the sections leads to the conclusion that there is probably no other book like it In this country. The volume aims at showing the results of practical experience, and it certainly may claim a complete achievement of this idea." Nature. "There can be no question as to its value. We cordially commend it to all concerned in the design and construction of the steam engine." Mechanical World. BOILER AND FACTORY CHIMNEYS. Their Draught-Power and Stability. With a chapter on Lightning Conductors. By ROBERT WILSON, A.I.C.E., Author of "A Treatise on Steam Boilers," &c. Crown 8vo, cloth 3/6 " A valuable contribution to the literature of scientific building." The Builder. BOILER MAKER'S READY RECKONER & ASSISTANT. With Examples of Practical Geometry and Templating, for the Use of Platers, Smiths, and Riveters. By JOHN COURTNEY, Edited by D. K. CLARK, M.I. C.E. Third Edition, 480 pp., with 140 Illustrations. Fcap. 8vo . "7/O " No workman or apprentice should be without this book." Iron Trade Circular. REFRIGERATING & ICE=MAKING MACHINERY. A Descriptive Treatise for the Use of Persons Employing Refrigerating and Ice-Making Installations, and others. By A. J. WALLIS-TAYLER, A.-M. Inst. C.E. Second Edition, Revised and Enlarged. With Illustrations. Crown 8vo, cloth. [Just Published. 7/6 "Practical, explicit, and profusely illustrated." Glasgow Herald. " We recommend the book, which gives the cost of various systems and illustrations showing details of parts of machinery and general arrangements of complete installations." Builder. " May be recommended as a useful description of the machinery, the processes, and of the facts, figures, and tabulated physics of refrigerating. It is one of the best compilations on the subject." Engineer. TEA MACHINERY AND TEA FACTORIES. A Descriptive Treatise on the Mechanical Appliances required in the Cultiva- tion of the Tea Plant and the Preparation of Tea for the Market. By A. J. WALLIS-TAYLER, A.-M. Inst. C.E. Medium 8vo, 468 pp. With 218 Illustrations. [Just Published. Net 25/O SUMMARY OF CONTENTS : MECHANICAL CULTIVATION OR TILLAGE OF THE SOIL. PLUCKING OR GATHERING THE LEAF. TEA FACTORIES. THE DRESSING, MANUFACTURE OR PREPARATION OF TEA BY MECHANICAL MEANS. ARTIFICIAL WITHERING OF THE LEAF. MACHINES FOR ROLLING OR CURLING THE LEAF. FER- MENTING PROCESS. MACHINES FOR THE AUTOMATIC DRYING OR FIRING OF THE LEAF. MACHINES FOR NON-AUTOMATIC DRYING OR FIRING OF THE LEAF. DRYING OR FIRING MACHINES. BREAKING OR CUTTING, AND SORTING MACHINES. PACKING THE TEA. MEANS OF TRANSPORT ON TEA PLANTATIONS. MISCELLANEOUS MACHINERY AND APPARATUS. FINAL TREATMENT OF THE TEA. TABLES AND MEMORANDA. "The subject of tea machinery is now one of the first interest to a large class of people, to whom we strongly commend the volume." Chamber of Commerce Journal. " When tea planting was first introduced into the British possessions little, if any, machinery was employed, but now its use is almost universal. This volume contains a very full account of the machinery necessary for the proper outfit of a factory, and also a description of the processes best carried out by this machinery." Journal Society of Arts. ENGINEERING ESTIMATES, COSTS, AND ACCOUNTS. A Guide to Commercial Engineering. With numerous examples of Estimates and Costs of Millwright Work, Miscellaneous Productions, Steam Engines and Steam Boilers ; and a Section on the Preparation of Costs Accounts. By A GENERAL MANAGER. Second Edition. 8vo, cloth. [Just Published. 1 2/O " This is an excellent and very useful book, covering subject-matter in constant requisition in every factory and workshop. . . . The book is invaluable, not only to the young engineer, but also to the estimate department of every works." Builder. " We accord the work unqualified praise. The information is given in a plain, straightforward manner, and bears throughout evidence of the intimate practical acquaintance of the author with every phase of commercial engineering." Mechanical World. CROSBY LOCK WOOD &> SON'S CATALOGUE. AERIAL OR WIRE=ROPE TRAMWAYS. Their Construction and Management. By A. J.WALLIS-TAYLER, A.M.Inst.C.E. With Si Illustrations. Crown 8vo, cloth. [Just Published. 7/6 "This is in its way an excellent volume. Without going into the minutiae of the subject, it yet lays before its readers a very good exposition of the various systems of rope transmission in use, and gives as well not a little valuable information about their working, repair, and management. We can safely recommend it as a useful general treatise on the subject." The Engineer. " Mr. Tayler has treated the subject as concisely as thoroughness would permit. The book will rank with the best on this useful topic, and we recommend it to those whose business is the transporting of minerals and goods." Mining Joicrnal. MOTOR CARS OR POWER=CARRIAQES FOR COMMON ROADS. By A. J. WALLIS-TAYLER, Assoc. Memb. Inst. C.E., Author of "Modern Cycles," &c. 212 pp., with 76 Illustrations. Crown 8vo, cloth . . 4/6 "Mr. Wallis-Tayler's book is a welcome addition to the literature of the subject, as it is the production of an Engineer, and has not been written with a view to assist in the promotion of companies. . . . The book is clearly expressed throughout, and is just the sort of work that an engineer, thinking of turning his attention to motor-carriage work, would do well to read as a preliminary to starting operations." Engineering. PLATING AND BOILER MAKING. A Practical Handbook for Workshop Operations. By JOSEPH G. HORNER, A.M.I. M.E. 380 pp. with 338 Illustrations. Crown 8vo, cloth . . 7/6 " The latest production from the pen of this writer is characterised by that evidence of close acquaintance with workshop methods which will render the book exceedingly acceptable to the practical hand. We have no hesitation in commending the work as a serviceable and practical handbook on a subject which has not hitherto received much attention from those qualified to deal writh it in a satisfactory manner." Mechanical World. PATTERN MAKING. A Practical Treatise, embracing the Main Types of Engineering Construction, and including Gearing, both Hand and Machine-made, Engine Work, Sheaves and Pulleys, Pipes and Columns, Screws, Machine Parts, Pumps and Cocks, the Moulding of Patterns in Loam and Greensand, &c., together with the methods of estimating the weight of Castings ; with an Appendix of Tables for Workshop Reference. By JOSEPH G. HORNER, A.M. I. M.E. Second Edition, Enlarged. With 450 Illustrations. Crown 8vo, cloth . ... . 7/6 " A well-written technical guide, evidently written by a man who understands and has prac- tised what he has written about. . . . We cordially recommend it to engineering students, young journeymen, and others desirous of being initiated into the mysteries of pattern-making." Builder. "An excellent -vade tnecnm for the apprentice who desires to become master of his trade.' English Mechanic. MECHANICAL ENGINEERING TERMS (Lockwood's Dictionary of). Embracing those current in the Drawing Office, Pattern Shop, Foundry, Fitting, Turning, Smiths', and Boiler Shops, &c., &c. Comprising upwards of 6,000 Definitions. Edited by JOSEPH G. HORNER, A.M. I. M.E. Second Edition, Revised, with Additions. Crown 8vo, cloth 7/6 "Just the sort of handy dictionary required by the various trades engaged in mechanical en- gineering. The practical engineering pupil will find the book of great value in his studies, and every foreman engineer and mechanic should have a copy." Building News. TOOTHED GEARING. A Practical Handbook for Offices and Workshops. By JOSEPH HORNER, A.M.I. M.E. With 184 Illustrations. Crown 8vo, cloth . . . 6/O " We must give the book our unqualified praise for its thoroughness of treatment, and we can heartily recommend it to all interested as the most practical book on the subject yet written." Mechanical World. FIRE PROTECTION. A Complete Manual of the Organisation, Machinery, Discipline and General Working of the Fire Brigade of London. By CAPTAIN EYRE M. SHAW, C.B., Chief Officer, Metropolitan Fire Brigade. New and Revised Edition, Demy 8vo, cloth Net 5/Q FIRES, FIRE=ENGINES, AND FIRE BRIGADES. With a History of Fire-Engines, their Construction, Use, and Manage- ment ; Foreign Fire Systems ; Hints on Fire-Brigades, &c. By CHARLES F. T. YOUNG, C.E. 8vo, cloth 1 4s. " To such of our readers as are interested in the subject of fires and fire apparatus we can most heartily commend this book." Engineering. MECHANICAL ENGiNEERING, STONE-WORKING MACHINERY. A Manual dealing with the Rapid and Economical Conversion of Stone. With Hints on the Arrangement and Management of Stone Works. By M. Powis BALE, M.I. M.E. Second Edition, enlarged. With Illustrations. Crown 8vo, cloth. [Just Published. QIQ " The book should be in the hands of every mason or student of stonework." Colliery Guardian. " A capital handbook for all who manipulate stone for building or ornamental purposes." Machinery Market. PUMPS AND PUMPING. A Handbook for Pump Users. Being Notes on Selection, Construction, and Management. By M. Powis BALE, M.I. M.E. Third Edition, Revised. Crown 8vo, cloth. [Just Published. 2/6 "The matter is set forth as concisely as possible. In fact, condensation rather than diflfiue- ness has been the author's aim throughout ; yet he does not seem to have omitted anything likely to be of use." Journal of Gas Lighting. " Thoroughly practical and simply and clearly written." Glasgow Herald. MILLING MACHINES AND PROCESSES. A Practical Treatise on Shaping Metals by Rotary Cutters. Including Information on Making and Grinding, the Cutters. By PAUL N. HASLUCK, Author of " Lathe-Work." 352 pp. With upwards of 300 Engravings. Large crown 8vo, cloth 1 2/6 " A new departure in engineering literature. . . . We can recommend this work to all in- terested in milling machines ; it is what it professes to be a practical treatise." Engineer. " A capital and reliable book which will no doubt be of considerable service both to those who are already acquainted with the process as well as to those who contemplate its adoption." Industries. LATHE=WORK. A Practical Treatise on the Tools, Appliances, and Processes employed in the Art of Turning. By PAUL N. HASLUCK. Sixth Edition. Crown 8vo, cloth 5/O " Written by a man who knows not only how work ought to be done, but who also knows how to do it, and how to convey his knowledge to others. To allturners this book would be valuable." Engineering. " We can safely recommend the work to young engineers. To the amateur it will simply be invaluable. To the student it will convey a great deal of useful information." Engineer. SCREW=THREADS, And Methods of Producing Them. With numerous Tables and complete Directions for using Screw-Cutting Lathes. By PAUL N. HASLUCK, Author of " Lathe- Work," &c. With Seventy-four Illustrations. Fifth Edition. Waistcoat-pocket size 1/6 " Full of useful information, hints and practical criticism. Taps, dies, and screwing tools generally are illustrated and their actions described." Mechanical H'orld. " It is a complete compendium of all the details of the screw-cutting lathe ; in fact a multum- in-parvo on all the subjects it treats upon." Carpenter and Builder. TABLES AND MEMORANDA FOR ENGINEERS, MECHANICS, ARCHITECTS, BUILDERS, &c. Selected and Arranged by FRANCIS SMITH. Sixth Edition, Revised, including ELECTRICAL TABLES, FORMULA, and MEMORANDA. Waistcoat-pocket size, limp leather. [Just Published. 1/6 " It would, perhaps, be as difficult to make a small pocket-book selection of notes and formulae to suit ALL engineers as it would be to make a universal medicine; but Mr. Smith's waistcoat- pocket collection may be looked upon as a successful attempt." Engineer. " The best example we have ever seen of 270 pages of useful matter packed into the dimen- sions of a card-case." Building News. " A veritable pocket treasury of knowledge." Iron. POCKET GLOSSARY OF TECHNICAL TERMS. English-French, French-English ; with Tables suitable for the Architectural, Engineering, Manufacturing, and Nautical Professions. By JOHN JAMES FLETCHER, Engineer and Surveyor. Second Edition, Revised and Enlarged. 200 pp. Waistcoat -pocket size, limp leather 1/6 " It is a very great advantage for readers and correspondents in France and England to have so large a number of the words relating to engineering and manufacturers collected in a lilliputian volume. The little book will be useful both to students and travellers." Architect. The glossary of terms is very complete, and many of the Tables are new and well arranged. We cordially commend the book." Mechanical World, CROSBY LOCK WOOD & SON'S CATALOGUE. THE ENGINEER'S YEAR BOOK FOR 1900. Comprising Formulae, Rules, Tables, Data and Memoranda in Civil, Mechanical, Electrical, Marine and Mine Engineering. By H. R. KEMPE, A.M. Inst. C.E., M.I.E.E., Technical Officer of the Engineer-in-Chief's Office, General Post Office, London, Author of "A Handbook of Electrical Testing." "The Electrical Engineer's Pocket- Book, "&c. Withabout 1,000 Illustrations, specially Engraved for the work. Crown 8vo, 800 pp., leather. [Just Published. 8/O "Represents an enormous quantity of work, and forms a desirable book of reference." The Engineer. " The volume is distinctly in advance of most similar publications in this country." Engineering. " This valuable and well -designed book of reference meets the demands of all descriptions of engineers." Saturday Review. " Teems with up-to-date information in every branch of engineering and construction." Building- News. " The needs of the engineering profession could hardly be supplied in a more admirable, complete and convenient form. To say that it more than sustains all comparisons is praise of the highest sort, and that may justly be said of it." Mining- Journal. " There is certainly room for the newcomer, which supplies explanations and directions, as well as formulae and tables. It deserves to become one of the most successful of the technical annuals. " A rchitect. " Brings together with great skill all the technical information which an engineer has to use day by day. It is in every way admirably equipped, and is sure to prove successful." Scotsman. " The up-to-dateness of Mr. Kempe's compilation is a quality that will not be lost on the busy people for whom the work is intended." Glasgow Herald. THE PORTABLE ENGINE. A Practical Manual on its Construction and Management. For the use of Owners and Users of Steam Engines generally. By WILLIAM DYSON WANSBROUGH. Crown 8vo, cloth 3/6 " This is a work of value to those who use steam machinery. . . . Should be read by every one who has a steam engine, on a farm or elsewhere." Mark Lane Express. " We cordially commend this work to buyers and owners of steam-engines, and to those who have to do with their construction or use." Timber Trades Journal. " Such a general knowledge of the steam-engine as Mr. Wansbrough furnishes to the reader should be acquired by all intelligent owners and others who use the steam-engine." Building News. "An excellent text-book of this useful form of engine. The ' Hints to Purchasers' contain a good deal of common-sense and practical wisdom." English Mechanic. IRON AND STEEL. A Work for the Forge, Foundry, Factory, and Office. Containing ready, useful, and trustworthy Information for Ironmasters and their Stock-takers ; Managers of Bar, Rail, Plate, and Sheet Rolling Mills; Iron and Metal Founders ; Iron Ship and Bridge Builders ; Mechanical, Mining, and Con- sulting Engineers ; Architects, Contractors, Builders, &c. By CHARLES HOARE, Author of "The Slide Rule," &c. Ninth Edition, samo, leather . 6/O " For comprehensiveness the book has not its equal." Iron. " One of the best of the pocket books." English Mechanic. CONDENSED MECHANICS. A Selection of Formulae, Rules, Tables, and Data or the Use of Engineering Students, Science Classes, &c. In accordance with the Requirements of the Science and Art Department. By W. G. CRAWFORD HUGHES, A.M.I.C.E. Crown 8vo, cloth 2/6 " The book is well fitted or those who are either confronted with practical problems in their work, or are preparing for examination and wish to refresh their knowledge by going through their formulae again." Marine Engineer. " It is well arranged, and meets the wants of those for whom it is intended." Railway News. THE SAFE USE OF STEAM. Containing Rules for Unprofessional Steam Users. By an ENGINEER. Seventh Edition. Sewed ..-. . . . 60. " If steam-users would but learn this little book by heart, boiler explosions would become sensations by their rarity." English Mechanic. HEATING BY HOT WATER. With Information and Suggestions on the best Methods of Heating Public, Private and Horticultural Buildings. By WALTER JONES. Second Edition. With 96 Illustrations, crown 8vo, cloth Net 21 Q "We confidently recommend all interested in heating by hot water to secure a copy of this valuable little treatise/' The Plumber and Decorator. MECHANICAL ENGINEERING, &>c. THE LOCOMOTIVE ENGINE. The Autobiography of an Old Locomotive Engine. By ROBERT WEATHER- BURN, M.I.M.E. With Illustrations and Portraits of GEORGE and ROBERT STEPHENSON. Crown 8vo, cloth. [fust Published. Net 2/6 SUMMARY OF CONTENTS: PROLOGUE. CYLINDERS. MOTIONS. CONNECTING RODS. FRAMES. WHEELS. PUMPS. CLACKS, &c. INJECTORS. BOILERS. SMOKE Box. CHIMNEY. WEATHER BOARD AND AWNING. INTERNAL DISSENSIONS. ENGINE DRIVERS, &c. " It would be difficult to imagine anything more ingeniously planned, more cleverly worked out, and more charmingly written. Readers cannot fail to find the volume most enjoyable." Glasgow Herald. THE LOCOMOTIVE ENGINE AND ITS DEVELOPMENT. A Popular Treatise on the Gradual Improvements made in Railway Engines between 1803 and 1896. By CLEMENT E. STRETTON, C.E. Fifth Edition, Enlarged. With 120 Illustrations. Crown 8vo, cloth. [Just Published. 3/6 " Students of railway history and all who are interested in the evolution of the modem loco- motive will find much to attract and entertain in this volume." The Times. LOCOMOTIVE ENGINE DRIVING. A Practical Manual for Engineers in Charge of Locomotive Engines. By MICHAEL REYNOLDS, Member of the Society of Engineers, formerly Loco- motive Inspector, L. B. & S. C. R. Ninth Edition. Including a KEY TO THE LOCOMOTIVE ENGINE. Crown 8vo, cloth 4/6 " Mr. Reynolds has supplied a want, and has supplied it well. We can confidently recom- mend the book not only to the practical driver, but to everyone who takes an interest in the performance of locomotive engines." The Engineer, "Mr. Reynolds has opened a new chapter in the literature of the day. His treatise is admirable. " A thetuzum, THE MODEL LOCOMOTIVE ENGINEER, Fireman, and Engine-Boy. Comprising a Historical Notice of the Pioneer Locomotive Engines and their Inventors. By MICHAEL REYNOLDS. Second Edition, with Revised Appendix. Crown 8vo, cloth. [Just Published. 4/6 " From the technical knowledge of the author, it will appeal to the railway man of to-day more forcibly than anything written by Dr. Smiles. . . . The volume contains information of a technical kind, and facts that every driver should be familiar with." English Mechanic. " We should be glad to see this book in the possession of everyone in the kingdom who has ever laid, or is to lay, hands on a locomotive engine." Iron. CONTINUOUS RAILWAY BRAKES. A Practical Treatise on the several Systems in Use in the United Kingdom : their Construction and Performance. With copious Illustrations and numerous Tables. By MICHAEL REYNOLDS. 8vo, cloth 9/O " A popular explanation of the different brakes. It will be of great assistance in forming public opinion, and will be studied with benefit by those who take an interest in the brake." English Mechanic. STATIONARY ENGINE DRIVING. A Practical Manual for Engineers in Charge of Stationary Engines. By MICHAEL REYNOLDS. Sixth Edition. Crown 8vo, cloth . . . 4/6 " The author is thoroughly acquainted with his subjects, and his advice on the various points treated is clear and practical. ... He has produced a manual which is an exceedingly useful one for the class for whom it is specially intended." Engineering. " Our author leaves no stone unturned. He is determined that his readers shall not only know something about the stationary engine, but all about it." Engineer. ENGINE-DRIVING LIFE. Stirring Adventure and Incidents in the Lives of Locomotive Engine- Drivers. By MICHAEL REYNOLDS. Third Edition. Crown 8vo, cloth . 1/6 " Perfectly fascinating. Wilkie Collins's most thrilling conceptions are thrown into the shade by true incidents, endless in their variety, related in every page." North British Mail. THE ENGINEMAN'S POCKET COMPANION, And Practical Educator for Enginemen, Boiler Attendants, and Mechanics. By MICHAEL REYNOLDS. With 45 Illustrations and numerous Diagrams. Fourth Edition, Revised. Royal i8mo, strongly bound for pocket wear 3/6 " This admirable work is well suited to accomplish its object, being the honest workmanship of a competent engineer." Glasgow Herald. io CROSBY LOCK WOOD &- SON'S CATALOGUE. CIVIL ENGINEERING, SURVEYING, &c. LIGHT RAILWAYS FOR THE UNITED KINGDOM, INDIA, AND THE COLONIES. A Practical Handbook setting forth the Principles on which Light Railways should be Constructed, Worked, and Financed ; and detailing the Cost of Construction, Equipment, Revenue and Working Expenses of Local Railways already established in the above-mentioned countries, and in Belgium, France, Switzerland, &c. By J. C. MACKAY, F.G.S., A.M. Inst. C.E. Illustrated with Plates and Diagrams. Medium 8vo, cloth. [Just Published. 1 5/Q " Mr. Mackay's volume is clearly and concisely written, admirably arranged, and freely Illustrated. The book is exactly what has been long wanted. We recommend it to all interested in the subject. It is sure to have a wide sale." Rail-way News. ^eneral information concerning almost all the light ly systems in the world will do well to-buy Mr. Mackay's book." Engineer Those who desire to have within reach ger " This work appears very opportunely, when the extension of the system on a large scale to England is at last being mooted. In its pages we find al' the information that the heart of man can desire on the subject. . . . every detail in its story, founded on the experience of other countries and applied to the possibilities of England, is put before us." Spectator. PRACTICAL TUNNELLING. Explaining in detail Setting-out the Works, Shaft-sinking, and Heading-driving, Ranging the Lines and Levelling underground, Sub-Excavating, Timbering and the Construction of the Brickwork of Tunnels, with the amount of Labour required for, and the Cost of, the various portions of the work. By FREDERICK W. SIMMS, M. Inst. C.E. Fourth Edition, Revised and Further Extended, including the most recent (1895) Examples of Sub-aqueous and other Tunnels, by D. KINNEAR CLARK, M. Inst. C.E. Imperial 8vo, with 34 Folding Plates and other Illustrations. Cloth. [Just Published. 2 2s. "The present (1896) edition has been brought right up to date, and is thus rendered a work to which civil engineers generally should have ready access, and to which engineers who have con- struction work can hardly afford to be without, but which to the younger members of the profession is invaluable, as from its pages they can learn the state to which the science of tunnelling has attained." Rail-way Nevis. " The estimation in which Mr. Simms's book has been held for many years cannot be more truly expressed than in the words of the late Prof. Rankine: ' The best source of information on the subject of tunnels is Mr. F. W. Simms's work on Practical Tunnelling." " Architect. THE WATER SUPPLY OF TOWNS AND THE CON- STRUCTION OF WATER-WORKS. A Practical Treatise for the Use of Engineers and Students of Engineering. By W. K. BURTON, A.M. Inst. C.E., Professor of Sanitary Engineering in the Imperial University, Tokyo, Japan, and Consulting Engineer to the Tokyo Water-works. Second Edition, Revised and Extended. With numerous Plates and Illustrations. Super-royal 8vo, buckram. [Just Published. 25/O I. INTRODUCTORY. II. DIFFERENT QUALITIES OF WATER. III. QUANTITY OF WATER TO BE PROVIDED. IV. ON ASCERTAINING WHETHER A PROPOSED SOURCE OF SUPPLY is SUFFICIENT. V. ON ESTIMATING THE STORAGE CAPACITY REQUIRED TO BE PROVIDED. VI. CLASSIFICATION OF WATER-WORKS. VII. IMPOUNDING RESER- VOIRS. VIII. EARTHWORK DAMS. IX. MASONRY DAMS. X. THE PURIFICATION OF WATER. XI. SETTLING RESERVOIRS. XII. SAND FILTRATION. XIII. PURIFICATION OF WATER BY ACTION OF IRON, SOFTENING OF WATER BY ACTION OF LIME, NATURAL FILTRATION. XIV. SERVICE OR CLEAN WATER RESERVOIRS WATER TOWERS STAND PIPES. XV. THE CONNECTION OF SETTLING RESERVOIRS, FILTER BEDS AND SERVICE RESERVOIRS. XVI. PUMPING MACHINERY. XVII. FLOW OF WATER IN CONDUITS- PIPES AND OPEN CHANNELS. XVIII. DISTRIBUTION SYSTEMS. XIX. SPECIAL PRO- VISIONS FOR THE EXTINCTION OF FIRE. XX. PIPES FOR WATER-WORKS. XXI. PRE- VENTION OF WASTE OF WATER. XXII. VARIOUS APPLICATIONS USED IN CONNECTION WITH WATER-WORKS. APPENDIX I. By PROF. JOHN MILNE, F.R.S. CONSIDERATIONS CONCERNING THE PROBABLE EFFECTS OF EARTHQUAKES ON WATER-WORKS, AND THE SPECIAL PRE- CAUTIONS TO BE TAKEN IN EARTHQUAKE COUNTRIES. APPENDIX II. By JOHN DE RIJKE, C.E. ON SAND DUNES AND DUNE SAND AS A SOURCE OF WATER SUPPLY. " The chapter upon filtration of water is very complete, and the details of construction well illustrated. . . . The work should be specially valuable to civil engineers engaged in work in Japan, but the interest is by no means confined to that locality." Engineer. " We congratulate the author upon the practical commonsense shown in the preparation of this work. . . . The plates and diagrams have evidently been prepared with great care, and cannot fail to be of great assistance to the student." Builder. " The whole art of water- works construction is dealt with in a clear and comprehensive fashion in this handsome volume. . . . Mr. Burton's practical treatise shows in all its sections the fruit of independent study and individual experience. It is largely based upon his own practice in the branch of engineering of which it treats. " Saturday Review. CIVIL ENGINEERING, SURVEYING, &>c. u THE WATER SUPPLY OF CITIES AND TOWNS. By WILLIAM HUMBER, A. M. Inst. C.E., and M.Inst M E., Author of "Cast and Wrought Iron Bridge Construction," &c., &c. Illustrated with 50 Double Plates, i Single Plate, Coloured Frontispiece, and upwards of 250 Woodcuts, and containing 400 pp. of Text. Imp. 410, elegantly and substantially balf-bound in morocco Net 6 6s. LIST OF CONTENTS. I. HISTORICAL SKETCH OF SOME OF THE MEANS THAT HAVE BEEN ADOPTED FOR THE SUPPLY OF WATER TO CITIES AND TOWNS. II. WATER AND THE FOREIGN MATTER USUALLY ASSOCIATED WITH IT. III. RAINFALL AND EVAPORATION. IV. SPRINGS AND THE WATER-BEARING FORMATIONS OF VARIOUS DISTRICTS. V. MEASUREMENT AND ESTIMATION OF THE FLOW OF WATER. VI. ON THE SELECTION OF THE SOURCE OF SUPPLY. VII. WELLS. VIII. RESERVOIRS. IX. THE PURIFICATION OF WATER. X. PUMPS. XI. PUMPING MACHINERY. XII. CONDUITS. XIII. DISTRIBUTION OF WATER. XIV. METERS, SERVICE PIPES, AND HOUSE FITTINGS. XV. THE LAW OF ECONOMY OF WATER-WORKS. XVI. CONSTANT AND INTERMITTENT SUPPLY. XVII. DESCRIPTION OF PLATES. APPENDICES, GIVING TABLES OF RATES OF SUPPLY, VELOCITIES, &c., &c., TOGETHER WITH SPECIFICATIONS OF SEVERAL WORKS ILLUSTRATED, AMONG WHICH WILL BE FOUND : ABERDEEN, BlDEFORD, CANTERBURY, DUNDEE, HALIFAX, LAMBETH, ROTHERHAM, DUBLIN, AND OTHERS. " The most systematic and valuable work upon water supply hitherto produced in English, or in any other language. It is characterised almost throughout by an exhaustiveness much more distinctive of French and German than of English technical treatises." Engineer. RURAL WATER SUPPLY. A Practical Handbook on the Supply of Water and Construction of Water- works for small Country Districts. By ALLAN GREENWELL, A.M.I.C.E., and W. T. CURRY, A.M.I.C.E., F.G.S. With Illustrations. Second Edition, Revised. Crown 8vo, cloth. [Just Published. 5/Q " We conscientiously recommend it as a very useful book for those concerned in obtaining water for small districts, giving a great deal of practical information in a small compass." Builder. " The volume contains valuable information upon all matters connected with water supply. . . . Full of details on points which are continually before water-works engineers." Nature. HYDRAULIC POWER ENGINEERING. A Practical Manual on the Concentration and Transmission of Power by Hydraulic Machinery. By G. CROYDON MARKS, A.M. Inst. C.E. With nearly 200 Illustrations. 8vo, cloth. [Just Published. Net 9/O SUMMARY OF CONTENTS: PRINCIPLES OF HYDRAULICS. THE OBSERVED FLOW OF WATER. HYDRAULIC PRESSURES, MATERIAL. TEST LOAD PACKINGS FOR SLIDING SURFACES. PIPE JOINTS. CONTROLLING VALVES.--PLATFORM LIFTS. WORKSHOP, FACTORY, AND DOCK CRANES. HYDRAULIC ACCUMULATORS. PRESSES. SHEET METAL WORKING AND FORGING MACHINERY. HYDRAULIC RIVETTF.RS. HAND, POWER, AND STEAM PUMPS. TURBINES. IMPULSE AND RE-ACTION TURBINES. DESIGN OF TUR- BINES. WATER WHEELS. HYDRAULIC ENGINES. RECENT ACHIEVEMENTS. TABLES. "We have nothing but praise for this thoroughly valuable work. The author has succeeded ia rendering his subject interesting as well as instructive." Practical Engineer. "Can be unhesitatingly recommended as a useful and up-to-date manual on hydraulic trans- mission and utilisation of power." Mechanical U'orld. HYDRAULIC TABLES, CO=EFFICIENTS, & FORMULAE. For Finding the Discharge of Water from Orifices, Notches, Weirs, Pipes, and Rivers. With New Formulae, Tables, and General Information on Rain-fall, Catchment-Basins, Drainage, Sewerage, Water Supply for Towns and Mill Power. By JOHN NEVILLE, Civil Engineer, M.R.I. A. Third Edition, revised, with additions. Numerous Illustrations. Crown 8vo, cloth . 1 4/O " It is, of all English books on the subject, the one nearest to completeness." Architect. HYDRAULIC MANUAL. Consisting of Working Tables and Explanatory Text. Intended as a Guide in Hydraulic Calculations and Field Operations. By Lowis D'A. JACKSON, Author of "Aid to Survey Practice," "Modern Metrology," &c. Fourth Edition, Enlarged. Large crown 8vo, cloth 1 6/O " The author has constructed a manual which may be accepted as a trustworthy guide to this branch of the engineer's profession." Engineering. WATER ENGINEERING. A Practical Treatise on the Measurement, Storage, Conveyance, and Utilisa- tion of Water for the Supply of Towns, for Mill Power, and for other Purposes. By C. SLAGG, A. M. Inst. C.E. Second Edition. Crown 8vo, cloth . 7/6 " As a small practical treatise on the water supply of towns, and on some applications of watet- power, the work is in many respects excellent." Engineering. 12 CROSBY LOCK WOOD &> SON'S CATALOGUE. THE RECLAMATION OF LAND FROM TIDAL WATERS. A Handbook for Engineers, Landed Proprietors, and others interested in Works of Reclamation. By ALEXANDER BEAZELEY, M.Inst. C.E. With Illustrations. 8vo, cloth. [Just Published. Net 1O/6 " The book shows in a concise way what has to be done in reclaiming land from the sea, and the best way of doing it. The work contains a great deal of practical and useful information which cannot fail to be of service to engineers entrusted with the enclosure of salt marshes, and to land owners intending to reclaim land from the sea." The Engineer. The author has carried out his task efficiently and well, and his book contains a large amount of information of great service to engineers and others interested in works of reclamation." Nature. MASONRY DAMS FROM INCEPTION TO COMPLETION. Including numerous Formulae, Forms of Specification and Tender, Pocket Diagram of Forces, &c. For the use of Civil and Mining Engineers. By C. F. COURTNEY, M. Inst. C.E. 8vo, cloth. [Just Published. 9/O " The volume contains a good deal of valuable data, and furnishes the engineer with practical advice. The author deals with his subject from the inception to the finish. Many useful sugges- tions will be found in the remarks on site and position, location of dam, foundations and construction." Building- News. RIVER BARS. The Causes of their Formation, and their Treatment by " Induced Tidal Scour ; " with a Description of the Successful Reduction by this Method of the Bar at Dublin. By I. J. MANN, Assist. Eng. to the Dublin Port and Docks Board. Royal 8vo, cloth 7IQ 'We recommend all interested in harbour works and, indeed, those concerned in the Improvements of rivers generally to read Mr. Mann's interesting work." Engineer. TRAMWAYS: THEIR CONSTRUCTION AND WORKING. Embracing a Comprehensive History of the System ; with an exhaustive Analysis of the Various Modes of Traction, including Horse Power, Steam, Cable Traction, Electric Traction, &c. ; a Description of the Varieties of Rolling Stock ; and ample Details of Cost and Working Expenses. New Edition, Thoroughly Revised, and Including the Progress recently made in Tramway Construction, &c., &c. By D. KINNEAR CLARK, M.Inst. C.E. With 400 Illustrations. 8 vo, 780 pp., buckram. [Just Published. 28'Q " The new volume is one which will rank, among tramway engineers and those interested in tramway working, with the Author's world-famed book on railway machinery." The Engineer. PRACTICAL SURVEYING. A Text-Book for Students preparing for Examinations or for Survey-work in the Colonies. By GEORGE W. USILL, A.M.I. C.E. With 4 Plates and up- wards of 330 Illustrations. Sixth Edition. Including Tables of Natural Sines, Tangents, Secants, &c. Crown 8vo, cloth 7/6 \ or, on THIN PAPER, leather, gilt edges, for pocket use. [Just Published. 1 2/8 " The best forms of instruments are described as to their construction, uses and modes of employment, and there are innumerable hints on work and equipment such as the author, in his experience as surveyor, draughtsman and teacher, has found necessary, and which the student in his inexperience will find most serviceable." Engineer. " The latest treatise in the English language on surveying, and we have no hesitation in say- Ing that the student will find it a better guide than any of its predecessors. Deserves to be recognised as the first book which should be put in the hands of a pupil of Civil Engineering." Architect. SURVEYING WITH THE TACHEOMETER. A practical Manual for the use of Civil and Military Engineers and Surveyors. Including two series of Tables specially computed for the Reduction of Readings in Sexagesimal and in Centesimal Degrees. By NEIL KENNEDY, M. Inst. C.E. With Diagrams and Plates. Demy 8vo, cloth. [Just Published. Net 1 O/6 "The work is very clearly written, and should remove all difficulties in the way of any surveyor desirous of making use of this useful and rapid instrument." Nature. AID TO SURVEY PRACTICE. For Reference in Surveying, Levelling, and Setting-out ; and in Route Sur- veys of Travellers by Land and Sea. With Tables, Illustrations, and Records. By Lowis D'A. JACKSON, A.M.I. C.E. 8vo, cloth .... 12/6 " A valuable -vade-mecum for the surveyor. We recommend this book as containing an admirable supplement to the teaching of the accomplished surveyor."- Afhentzutn. " The author brings to his work a fortunate union of theory and practical experience whlrh, aided by a clear and lucid style of writing, renders the book a very useful o\\e."ftuilder. CIVIL ENGINEERING, SURVEYING, &>c. 13 ENGINEER'S & MINING SURVEYOR'S FIELD BOOK. Consisting of a Series of Tables, with Rules, Explanations of Systems, and use of Theodolite for Traverse Surveying and plotting the work with minute accuracy by means of Straight Edge and Set Square only ; Levelling with the Theodolite, Casting-out and Reducing Levels to Datum, and Plotting Sections in the ordinary manner ; Setting-out Curves with the Theodolite by Tangential Angles and Multiples with Right and Left-hand Readings of the Instrument ; Setting-out Curves without Theodolite on the System of Tangential Angles by Sets of Tangents and Offsets ; and Earthwork Tables to 80 feet deep, calcu- lated for every 6 inches in depth. By W. DAVIS HASKOLL, C.E. With numerous Woodcuts. Fourth Edition, Enlarged. Crown 8vo, cloth . 1 2/O " The book is very handy ; the separate tables of sines and tangents to every minute will make it useful for many other purposes, the genuine traverse tables existing all the same." Athenaum. " Every person engaged in engineering field operations will estimate the importance of such a work and the amount of valuable time which will be saved by reference to a set of reliable tables prepared with the accuracy and fulness of those given in this volume." Rail-way News. LAND AND MARINE SURVEYING. In Reference to the Preparation of Plans for Roads and Railways ; Canals, Rivers, Towns' Water Supplies ; Docks and Harbours. With Description and Use of Surveying Instruments. By W. DAVIS HASKOLL, C.E. Second Edition, Revised, with Additions. Large crown 8vo, cloth . . . 9/O " This book must prove of great value to the student. We have no hesitation in recom- mending it, feeling assured that it will more than repay a careful study." Mechanical World. " A most useful book for the student. We strongly recommend it as a carefully-written and valuable text-book. It enjoys a well-deserved repute among surveyors." Builder. " This volume cannot fail to prove of the utmost practical utility. It may be safely recom- mended to all students who aspire to become clean and expert surveyors." Mining Journal. PRINCIPLES AND PRACTICE OF LEVELLING. Showing its Application to Purposes of Railway and Civil Engineering in the Construction of Roads ; with Mr. TELFORD'S Rules for the same. By FREDERICK W. SIMMS, F.G.S., M. Inst. C.E. Eighth Edition, with the addition of LAW'S Practical Examples for Setting-out Railway Curves, and TRAUTWINE'S Field Practice of Laying-out Circular Curves. With 7 Plates and numerous Woodcuts, 8vo, cloth 8/6 *** TRAUTWINE on CURVES may be had separate 5/O " The text-book on levelling in most of our engineering schools and colleges." Engineer. "The publishers have rendered a substantial service to the profession, especially to the younger members, by bringing out the present edition of Mr. Simms's useful work." Engineering. AN OUTLINE OF THE METHOD OF CONDUCTING A TRIGONOMETRICAL SURVEY. For the Formation of Geographical and Topographical Maps and Plans, Mili- tary Reconnaissance, LEVELLING, &c., with Useful Problems, Formulae, and Tables. By Lieut. -General FROME, R.E. Fourth Edition, Revised and partly Re-written by Major-General Sir CHARLES WARREN, G.C.M.G., R.E. With 19 Plates and 115 Woodcuts, royal 8vo, cloth .... 1 Q/O " No words of praise from us can strengthen the position so well and so steadily maintained by this work. Sir Charles Warren has revised the entire work, and made such additions as were necessary to bring every portion of the contents up to the present date." Broad Arrow. TABLES OF TANGENTIAL ANGLES AND MULTIPLES FOR 5ETTING- OUT CURVES. From 5 to 200 Radius. By A. BEAZELEY, M. Inst. C.E. 6th Edition, Revised. With an Appendix on the use of the Tables for Measuring up Curves. Printed on 50 Cards, and sold in a cloth box, waistcoat-pocket size. [Just Published. 3/6 " Each table is printed on a card, which, placed on the theodolite, leaves the hands free to manipulate the instrument no small advantage as regards the rapidity of work." Engineer. " Very handy : a man may know that all his day's work must fall on two of these cards, which he puts into his own card-case, and leaves the rest behind." Athenceum. HANDY GENERAL EARTH=WORK TABLES. Giving the Contents in Cubic Yards of Centre and Slopes of Cuttings and Embankments from 3 inches to 80 feet in Depth or Height, for use with either 66 feet Chain or 100 feet Chain. By J. H. WATSON BUCK, M. Inst. C.E. On a Sheet mounted in cloth case. [Just Published. 3/6 i 4 CROSBY LOCK WOOD 6- SON'S CATALOGUE. EARTHWORK TABLES. Showing the Contents in Cubic Yards of Embankments, Cuttings, &c., of Heights or Depths up to an average of 80 feet. By JOSEPH BROADBENT, C.E., and FRANCIS CAMPIN, C.E. Crown 8vo, cloth 5/O " The way in which accuracy is attained, by a simple division of each cross section into three elements, two in which are constant and one variable, is ingenious." Athenczum. A MANUAL ON EARTHWORK. By ALEX. J. S. GRAHAM, C.E. With numerous Diagrams. Second Edition. T8mo, cloth 2/6 THE CONSTRUCTION OF LARGE TUNNEL SHAFTS. A Practical and Theoretical Essay. By J. H. WATSON BUCK, M. Inst. C.E., Resident Engineer, L. and N. W. R. With Folding Plates, 8vo, cloth 1 2/O " Many of the methods given are of extreme practical value to the mason, and the observa- tions on the form of arch, the rules for ordering the stone, and the construction of the templates, will be found of considerable use. We commend the book to the engineering profession." Building News. " Will be regarded by civil engineers as of the utmost value, and calculated to save much time and obviate many mistakes." Colliery Guardian. CAST & WROUGHT IRON BRIDGE CONSTRUCTION (A Complete and Practical Treatise on), including Iron Foundations. In Three Parts. Theoretical, Practical, and Descriptive. By WILLIAM HUMBER, A. M. Inst. C.E., and M. Inst. M.E. Third Edition, revised and much im- proved, with 115 Double Plates (20 of which now first appear in this edition), and numerous Additions to the Text. In 2 vols., imp. 410, half-bound in morocco 6 16s. 60. " A very valuable contribution to the standard literature of civil engineering. In addition to elevations, plans, and sections, large scale details are given, which very much enhance the instructive worth of those illustrations." Civil Engineer and Architect' s Journal. "Mr. Humber's stately volumes, lately issued in which the most important bridges erected during the last five years, under the direction of the late Mr. Brunei, Sir W. Cubitt, Mr. Hawkshaw, Mr. Page, Mr. Fowler, Mr. Hemans, and others among our most eminent engineers, are drawn and specified in great detail." Engineer. ESSAY ON OBLIQUE BRIDGES (Practical and Theoretical). With 13 large Plates. By the late GEORGE WATSON BUCK, M.I. C.E. Fourth Edition, revised by his Son, J. H. WATSON BUCK, M.I. C.E. ; and with the addition of Description to Diagrams for Facilitating the Construction of Oblique Bridges, by W. H. BARLOW, M.I. C.E. Royal 8vo, cloth 1 2/O " The standard text-book for all engineers regarding skew arches is Mr. Buck's treatise, and it would be impossible to consult a better." Engineer. "Mr. Buck's treatise is recognised as a standard text-book, and his treatment has divested the subject of many of the intricacies supposed to belong to it. As a guide to the engineer and architect, on a confessedly difficult subject, Mr. Buck's work is unsurpassed." Building News. THE CONSTRUCTION OF OBLIQUE ARCHES (A Practical Treatise on). By JOHN HART. Third Edition, with Plates. Imperial 8vo, cloth 8/O GRAPHIC AND ANALYTIC STATICS. In their Practical Application to the Treatment of Stresses in Roofs, Solid Girders, Lattice, Bowstring, and Suspension Bridges, Braced Iron Arches and Piers, and other Frameworks. By R. HUDSON GRAHAM, C.E. Containing Diagrams and Plates to Scale. With numerous Examples, many taken from existing Structures. Specially arranged for Class-work in Colleges and Universities. Second Edition, Revised and Enlarged. 8vo, cloth . 1 6/O " Mr. Graham's book will find a place wherever graphic and analytic statics are used or studied. " Engineer. " The work is excellent from a practical point of view, and has evidently been prepared with much care. The directions for working are simple, and are illustrated by an abundance of well-selected examples. It is an excellent text-book for the practical draughtsman." Athenaum. WEIGHTS OF WROUGHT IRON & STEEL GIRDERS. A Graphic Table for Facilitating the Computation of the Weights of Wrought Iron and Steel Girders, &c., for Parliamentary and other Estimates. By J. H. WATSON BUCK, M. Inst. C.E. On a Sheet ... | 2/6 CIVIL ENGINEERING, SURVEYING, &*. 15 PRACTICAL GEOMETRY. For the Architect, Engineer, and Mechanic. Giving Rules for the Delineation and Application of various Geometrical Lines, Figures, and Curves. By E. W. TARN, M.A., Architect. 8vo, cloth 9/O " No book with the same objects in view has ever been published in which the clearness of the rules laid down and the illustrative diagrams have been so satisfactory." Scotsman. THE GEOMETRY OF COMPASSES. Or, Problems Resolved by the mere Description of Circles and the Use of Coloured Diagrams and Symbols. By OLIVER BYRNE. Coloured Plates. Crown 8vo, cloth 3/6 HANDY BOOK FOR THE CALCULATION OF STRAINS In Girders and Similar Structures and their Strength. Consisting of Formulae and Corresponding Diagrams, with numerous details for Practical Applica- tion, &c. By WILLIAM HUMBER, A. M. Inst. C.E., &c. Fifth Edition. Crown 8vo, with nearly 100 Woodcuts and 3 Plates, cloth . . . 7IQ "The formulae are neatly expressed, and the diagrams good." Athcnaum. "We heartily commend this really handy book to our engineer and architect readers." English Mechanic. TRUSSES OF WOOD AND IRON. Practical Applications of Science in Determining the Stresses, Breaking Weights, Safe Loads, Scantlings, and Details of Construction. With Complete Working Drawings. By WILLIAM GRIFFITHS, Surveyor. 8vo, cloth. 4/6 "This handy little book enters so minutely into every detail connected with the con- struction of roof trusses that no student need be ignorant of these matters." Practical Engineer. THE STRAINS ON STRUCTURES OF IRONWORK. With Practical Remarks on Iron Construction. By F. W. SHEILDS, M.I.C.E. 8vo, cloth . . . 5/O A TREATISE ON THE STRENGTH OF MATERIALS. With Rules for Application in Architecture, the Construction of Suspension Bridges, Railways, &c. By PETER BARLOW, F.R.S. A new Edition, revised by his Sons, P. W. BARLOW, F.R.S., and W. H. BARLOW, F.R.S. ; to which are added, Experiments by HODGKINSON, FAIRBAIRN, and KIRKALDY; and Formulae for calculating Girders, &c. Arranged and Edited by WM. HUMBER, A. M.Inst. C.E. 8vo, cloth 1 8/O " Valuable alike to the student, tyro, and the experienced practitioner, it will always rank in future as it has hitherto done, as the standard treatise on that particular subject." Engineer. " As a scientific work of the first class, it deserves a foremost place on the bookshelves of every civil engineer and practical mechanic." English Mechanic. STRENGTH OF CAST IRON AND OTHER METALS. By THOMAS TREDGOLD, C.E. Fifth Edition, including HODGKINSON'S Experi- mental Researches. 8vo, cloth 1 2/O SAFE RAILWAY WORKING. A Treatise on Railway Accidents, their Cause and Prevention ; with a De- scription of Modern Appliances and Systems. By CLEMENT E. STRETTON, C.E., Vice-President and Consulting Engineer, Amalgamated Society of Railway Servants. With Illustrations and Coloured Plates. Third Edition, Enlarged. Crown 8vo, cloth . . ... ... . . 3/6 " A book for the engineer, the directors, the managers ; and, in short, all who wish for information on railway matters will find a perfect encyclopaedia in 'Safe Railway Working.'" Railway Review. " We commend the remarks on railway signalling to all railway managers, especially where a uniform code and practice is advocated." Herepath's Rail-way Journal. EXPANSION OF STRUCTURES BY HEAT. By JOHN KEILY, C.E., late of the Indian Public Works Department. Crown 8vo, cloth 3/6 " The aim the author has set before him, viz., to show the effects of heat upon metallic and other structures, is a laudable one, for this is a branch of physics upon which the engineer or architect can find but little reliable and comprehensive data in books." Builder, 16 CROSBY LOCKWOOD & SON'S CATALOGUE. THE PROGRESS OF MODERN ENGINEERING. Complete in Four Volumes, imperial 410, half-morocco, price ~| 2 1 2s. Each volume sold separately, as follows : FIRST SERIES, Comprising Civil, Mechanical, Marine, Hydraulic, Railway, Bridge, and other Engineering Works, &c. By WILLIAM HUMBER, A. M. Inst. C.E.,&c. Imp. 4to, with 36 Double Plates, drawn to a large scale, Photographic Portrait of John Hawkshaw, C.E., F.R.S., &c., and copious descriptive Letterpress, Specifications, &c. Half-morocco . . 3 3s. LIST OF THE PLATES AND DIAGRAMS. VICTORIA STATION AND ROOF, L. B. & S. C. R. (8 PLATES) ; SOUTHPORT PIER (2 PLATES) ; VICTORIA STATION AND ROOF, L. C. & D. AND G. W. R. (6 PLATES) ; ROOF OF CREMORNE Music HALL; BRIDGE OVER G. N. RAILWAY; ROOF OF STATION, DUTCH RHENISH RAIL. (2 PLATES); BRIDGE OVER THE THAMES, WEST LONDON KXTENSION RAILWAY (5 PLATES); ARMOUR PLATES: SUSPENSION BRIDGE, THAMES (4 PLATES) ; THE ALLEN ENGINE ; SUSPENSION BRIDGE, AVON (3 PLATES) ; UNDER- GROUND RAILWAY (3 PLATES). HUMBER'S MODERN ENGINEERING. SECOND SERIES. Imp. 410, with 3 Double Plates, Photographic Portrait of Robert Stephenson, C.E., M.P., F.R.S., &c., and copious descriptive Letter- press, Specifications, &c. Half-morocco 3 3s. LIST OF THE PLATES AND DIAGRAMS. BlRKENHEAD DOCKS, LOW WATER BASIN (15 PLATES) ; CHARING CROSS STATION ROOF, C. C. RAILWAY (3 PLATES); DIGSWELL VIADUCT, GREAT NORTHERN RAILWAY; ROBBERY WOOD VIADUCT, GREAT NORTHERN RAILWAY; IRON PERMANENT WAY; CLYDACH VIADUCT, MERTHYR, TREDEGAR, AND ABERGAVENNY RAILWAY ; EBBW VIADUCT, MERTHYR, TREDEGAR, AND ABERGAVENNY RAILWAY; COLLEGE WOOD VIADUCT, CORNWALL RAILWAY; DUBLIN WINTER PALACE ROOF (3 PLATES); BRIDGE OVER THE THAMES, L. C. & D. RAILWAY (6 PLATES); ALBERT HARBOUR, GREENOCK (4 PLATES). HUMBER'S MODERN ENGINEERING. THIRD SERIES. Imp. 4to, with 40 Double Plates, Photographic Portrait of J. R. M'Clean, late Pres. Inst. C.E., and copious descriptive Letterpress, Specifications, &c. Half-morocco 3 3s. LIST OF THE PLATES AND DIAGRAMS. MAIN DRAINAGE, METROPOLIS. North Side. MAP SHOWING INTERCEPTION OF SEWERS; MIDDLE LEVEL SEWER (2 PLATES); OUTFALL SEWER, BRIDGE OVER RIVER LEA (3 PLATES); OUTFALL SEWER, BRIDGE OVER MARSH LANE, NORTH WOOLWICH RAILWAY, AND Bow AND BARKING RAILWAY JUNCTION; OUTFALL SEWER, BRIDGE OVER Bow AND BARKING RAILWAY (3 PLATES) ; OUTFALL SEWER, BRIDGE OVER EAST LONDON WATER-WORKS' FEEDER (2 PLATES) ; OUTFALL SEWER RESERVOIR (2 PLATES) ; OUTFALL SEWER, TUMBLING BAY AND OUTLET ; OUTFALL SEWER, PENSTOCKS. South Side. OUTFALL SEWER, BERMONDSEY BRANCH (2 PLATES) ; OUTFALL SEWER, RESERVOIR AND OUTLET (4 PLATES) ; OUTFALL SEWER, FILTH HOIST ; SECTIONS OF SEWERS NORTH AND SOUTH SIDES). THAMES EMBANKMENT. SECTION OF RIVER WALL; STEAMBOAT PIER, WEST- MINSTER (2 PLATES) ; LANDING STAIRS BETWEEN CHARING CROSS AND WATERLOO BRIDGES ; YORK GATE (2 PLATES) ; OVERFLOW AND OUTLET AT SAVOY STREET SEWER (3 PLATES); STEAMBOAT PIER, WATERLOO BRIDGE (3 PLATES) ; JUNCTION OF SEWERS, PLANS AND SECTIONS; GULLIES, PLANS AND SECTIONS; ROLLING STOCK ; GRANITE AND IRON FORTS. HUMBER'S MODERN ENGINEERING. FOURTH SERIES. Imp. 4to, with 36 Double Plates, Photographic Portrait of John Fowler, late Pres. Inst. C.E., and copious descriptive Letterpress, Speci- fications, &c. Half-morocco 3 3s. LIST OF THE PLATES AND DIAGRAMS. ABBEY MILLS PUMPING STATION, MAIN DRAINAGE, METROPOLIS (4 PLATES) ; BARROW DOCKS (5 PLATES); MANQUIS VIADUCT, SANTIAGO AND VALPARAISO RAILWAY, (2 PLATES); ADAM'S LOCOMOTIVE, ST. HELEN'S CANAL RAILWAY (2 PLATES); CANNON STREET STATION ROOF, CHARING CROSS RAILWAY (3 PLATES); ROAD BRIDGE OVER THE RIVER MOKA (2 PLATES) ; TELEGRAPHIC APPARATUS FOR MESOPOTAMIA ; VIADUCT OVER THE RIVER WYE, MIDLAND RAILWAY (3 PLATES); ST. GERMANS VIADUCT, CORNWALL RAILWAY (2 PLATES); WROUGHT-IRON CYLINDER FOR DIVING BELL; MlLLWALL DOCKS (6 PLATES); MlLROY'S PATENT EXCAVATOR ; METROPOLITAN DIS- TRICT RAILWAY (6 PLATF.S) ; HARBOURS, PORTS. AND BREAKWATERS (3 PLATES). MARINE ENGINEERING, NAVIGATION. &-c. 17 MARINE ENGINEERING, SHIPBUILDING, NAVIGATION, &c. THE NAVAL ARCHITECT'S AND SHIPBUILDER'S POCKET-BOOK of Formulae, Rules, and Tables, and Marine Engineer's and Surveyor's Handy Book of Reference. By CLEMENT MACKROW, M.I.N.A. Seventh Edition, 700 pp., with 300 Illustrations. Fcap., leather . . 12/6 SUMMARY OF CONTENTS : SIGNS AND SYMBOLS, DECIMAL FRACTIONS. TRIGONO- METRY. PRACTICAL GEOMETRY. MENSURATION. CENTRES AND MOMENTS OF FIGURES. MOMENTS OF INERTIA AND RADII OF GYRATION. ALGEBRAICAL EXPRESSIONS FOR SIMPSON'S RULES. MECHANICAL PRINCIPLES. CENTRE OF GRAVITY. LAWS OF MOTION. DISPLACEMENT, CENTRE OF BUOYANCY. CENTRE OF GRAVITY OF SHIP'S HULL. STABILITY CURVES AND METACENTRES. SEA AND SHALLOW-WATER WAVES. ROLLING OF SHIPS. PROPULSION AND RESISTANCE OF VESSELS. SPEED TRIALS. SAILING, CENTRE OF EFFORT. DISTANCES DOWN RIVERS, COAST LINES. STEERING AND RUDDERS OF VESSELS. LAUNCHING CALCULATIONS AND VELOCITIES. WEIGHT OF MATERIAL AND GEAR. GUN PARTICULARS AND WEIGHT. STANDARD GAUGES. RIVETED JOINTS AND RIVETING. STRENGTH AND TESTS OF MATERIALS. BINDING AND SHEARING STRESSES, &c. STRENGTH OF SHAFTING, PILLARS, WHEELS, &c. HYDRAULIC DATA, &c. CONIC SECTIONS, CATENARIAN CURVES. MECHANICAL POWERS, WORK. BOARD OF TRADE REGULATIONS FOR BOILERS AND ENGINES. BOARD OF TRADE REGULATIONS FOR SHIPS. LLOYD s RULES FOR BOILERS. LLOYD'S WEIGHT OF CHAINS. LLOYD'S SCANTLINGS FOR SHIPS. DATA OF ENGINES AND VESSELS. SHIPS' FITTINGS AND TESTS. SEASONING PRESERVING TIMBER. MEASUREMENT OF TIMBER. ALLOYS, PAINTS, VARNISHES. DATA FOR STOWAGE. ADMIRALTY TRANS- PORT REGULATIONS. RULES FOR HORSE-POWER, SCREW PROPELLERS, &c. PER- CENTAGES FOR BUTT STRAPS, &c. PARTICULARS OF YACHTS. MASTING AND RIGGING VESSELS. DISTANCES OF FOREIGN PORTS. TONNAGE TABLES. VOCABULARY OF FRENCH AND ENGLISH TERMS. ENGLISH WEIGHTS AND MEASURES. FOREIGN WEIGHTS AND MEASURES. DECIMAL EQUIVALENTS. FOREIGN MONEY. DISCOUNT AND WAGES TABLES. USEFUL NUMBERS AND READY RECKONERS. TABLES OF CIRCULAR MEASURES. TABLES OF AREAS OF AND CIRCUMFERENCES OF CIRCLES. TABLES OF AREAS OF SEGMENTS OF CIRCLES. TABLES OF SQUARES AND CUBES AND ROOTS OF NUMBERS. TABLES OF LOGARITHMS OF NUMBERS. TABLES OF HYPER- BOLIC LOGARITHMS. TABLES OF NATURAL SINES, TANGENTS, &c. TABLES OF LOGARITHMIC SINES, TANGENTS, &c. " In these days of advanced knowledge a work like this is of the greatest value. It contains a vast amount of information. We unhesitatingly say that it is the most valuable compilation for its specific purpose that has ever been printed. No naval architect, engineer, surveyor, or seaman, wood or iron shipbuilder, can afford to be without this work." Nautical Magazine. " Should be used by all who are engaged in the construction or design of vessels. . . . Will be found to contain the most useful tables and formulas required by shipbuilders, carefully collected from the best authorities, and put together in a popular and simple form. The book is one of exceptional merit." Engineer. " The professional shipbuilder has now, in a convenient and accessible form, reliable data for solving many of the numerous problems that present themselves in the course of his work." iron. " There is no doubt that a pocket-book of this description must be a necessity in the ship- building trade. . . The volume contains a mass of useful information clearly expressed and presented in a handy fcrm." Marine Engineer. WANNAN'S MARINE ENGINEER'S GUIDE To Board of Trade Examinations for Certificates of Competency. Containing all Latest Questions to Date, with Simple, Clear, and Correct Solutions ; Elementary and Verbal Questions and Answers ; complete Set of Drawings with Statements completed. By A. C. WANNAN, C.E., and E. W. I. WANNAN, M.I.M.E. Illustrated with numerous Engravings. Crown 8vo, 370 pages, cloth. 8/6 " The book is clearly and plainly written and avoids unnecessary explanations and formulas and we consider it a valuable book for students of marine engineering." Nautical Magazine, WANNAN'S MARINE ENGINEER'S POCKET-BOOK. Containing the Latest Board of Trade Rules and Data for Marine Engineers. By A. C. WANNAN. Second Edition, carefully Revised, Square i8mo, with thumb Index, leather. 5/O "There is a great deal of useful information in this little pocket-book. It is of the rule-pf- thumb order, and is, on that account, well adapted to the uses of the sea-going engineer." . Engineer. MARINE ENGINES AND STEAM VESSELS. A Treatise on. By ROBERT MURRAY, C.E. Eighth Edition, thoroughly Revised, with considerable Additions by the Author and by GEORGE CARLISLE, C.E., Senior Surveyor to the Board of Trade, izmo, cloth 4/8 L. B 1 8 CROSBY LOCK WOOD & SON'S CATALOGUE. SEA TERMS, PHRASES, AND WORDS (Technical Dictionary of) used in the English and French Languages (English- French, French -English). For the Use of Seamen, Engineers, Pilots, Shipbuilders, Shipowners, and Ship-brokers. Compiled by W. PIRRIE, late of the African Steamship Company. Fcap. 8vo, cloth limp . . . 5/O " This volume will be highly appreciated by seamen, engineers, pilots, shipbuilders and ship- owners. It will be found wonderfully accurate and complete." Scotsman. " A very useful dictionary, which has long been wanted by French and English engineers, masters, officers and others." Shipping World. ELECTRIC SHIP-LIGHTING. A Handbook on the Practical Fitting and Running of Ships' Electrical Plant, for the Use of Shipowners and Builders, Marine Electricians and Sea-going Engineers in Charge. By J. W. URQUHART, Author of "Electric Light." "Dynamo Construction." &c. Second Edition, Revised and Extended. 326 pp., with 88 Illustrations. Crown 8vo, cloth. [Just Published. 7IQ MARINE ENGINEER'S POCKET-BOOK. Consisting of useful Tables and Formulae. By FRANK PROCTOR, A.I.N.A. Third Edition. Royal samo, leather, gilt edges, with strap . . . 4/O " We recommend it to our readers as going far to supply a long-felt want." Naval Science. " A most useful companion to all marine engineers." United Service Gazette. ELEMENTARY ENGINEERING. A Manual for Young Marine Engineers and Apprentices. In the Form of Questions and Answers on Metals, Alloys, Strength of Materials, Construction and Management of Marine Engines and Boilers, Geometry, &c., &c. With an Appendix of Useful Tables. By J. S. BREWER. Crown 8vo, cloth . 1/6 " Contains much valuable information for the class for whom it is intended, especially in the chapters on the management of boilers and engines." Nautical Magazine. PRACTICAL NAVIGATION. Consisting of THE SAILOR'S SEA-HOOK, by JAMES GREENWOOD and W. H. ROSSER ; together with the exquisite Mathematical and Nautical Tables for the Working of the Problems, by HENRY LAW, C.E., and Professor J. R. YOUNG. Illustrated. i2mo, strongly half-bound 7/O MARINE ENGINEER'S DRAWING-BOOK. Adapted to the Requirements of the Board of Trade Examinations. By JOHN LOCKIE, C.E. With 22 Plates, Drawn to Scale. Royal 8vo, cloth . 3/6 THE ART AND SCIENCE OF SAILMAKING. By SAMUEL B. SADLER, Practical Sailmaker, late in the employment of Messrs. Ratsey and Lapthorne, of Cowes and Gosport. With Plates and Other Illustrations. Small 4to, cloth ....... 1 2/6 " This extremely practical work gives a complete education in all the branches of the manu- facture, cutting out, roping, seaming, and goring. It is copiously illustrated, and will form a first- rate text-book and guide." Portsmouth. Times. CHAIN CABLES AND CHAINS. Comprising Sizes and Curves of Links, Studs, &c., Iron for Cables and Chains, Chain Cable and Chain Making, Forming and Welding Links, Strength of Cables and Chains, Certificates for Cables, Marking Cables, Prices of Chain Cables and Chains, Historical Notes, Acts of Parliament, Statutory Tests, Charges for Testing, List of Manufacturers of Cables, &c., &c. By THOMAS W. TRAILL, F.E.R.N., M.Inst.C.E., Engineer-Surveyor-in -Chief, Board of Trade, Inspector of Chain Cable and Anchor Proving Establishments, and General Superintendent Lloyd's Committee on Proving Establishments. With numerous Tables, Illustrations, and Lithographic Drawings. Folio, cloth, bevelled boards .......... 2 2s. "It contains a vast amount of valuable infotmation. Nothing seems to be wanting to make it complete and standard work of reference on the subject." Nautical Magazine. MINING, METALLURGY, ^COLLIERY WORKING. 19 MINING, METALLURGY, AND COLLIERY WORKING. THE METALLURGY OF GOLD. A Practical Treatise on the Metallurgical Treatment of Gold-bearing Ores. Including the Assaying, Melting, and Refining of Gold. By M. EISKLEK, Mining Engineer, A.I.M.E., Member of the Institute of Mining and Metal- lurgy. Author of " Modern High Explosives," "The Metallurgy of Silver, &c., &c. Fifth Edition, Enlarged and Re-arranged. With over 300 illustra- tions and numerous Folding Plates, Medium Svo, cloth. [Just Published. Net 21 /O " This book thoroughly deserves its title of a ' Practical Treatise.' The whole process of gold nulling, from the breaking of the quartz to the assay of the bullion, is described in clear and orderly narrative and with much, but not too much, fulness of detail." Saturday Review. " The work is a storehouse of information and valuable data, and we strongly recommend it to all professional men engaged in the gold-mining industry." Mining Journal. THE CYANIDE PROCESS OF GOLD EXTRACTION. Including its Practical Application on the Witwatersrand Gold Fields in South Africa. By M. EISSLER, M.E., Author of "The Metallurgy of Gold," &c. With Diagrams and Working Drawings. Second Edition, Revised and En- larged. Svo, cloth. 7/6 "This book is just what was needed to acquaint mining men with the actual working of a process which is not only the irost popular, but is, as a general rule, the most successful for the extraction of gold from tailings." Mining Journal. " The work will prove invaluable to all interested in gold mining, whether metallurgists or as investors." Chemical News. DIAMOND DRILLING FOR GOLD & OTHER MINERALS. A Practical Handbook on the Use of Modern Diamond Core Drills in Pro- specting and Exploiting Mineral-Bearing Properties, including Particulars of the Costs of Apparatus and Working. By G. A. DENNY, M.N.E. Inst. M.E., M I.M. and M. Author of "The Klerksdorp Goldfields." Medium Svo, 168 pp., with Illustrative Diagrams. [Just Published. 1 2/6 " There is certainly scope f->r a work on diimond drilling, and Mr. Denny deserves grateful recognition for supplving a decided want. We strongly recommend every board of directors to carefully peruse the pages treating of the applicability of diamond drilling to aurifero"S deposits and, under certain conditions, its advantages over shaft sinking for systematic prospecting, both from the surface and underground. The author has given us a valuable volume of eminently practical data that should be in the possession of thos interested in mining." Mining Journal. " Mr. Denny's handbook is the first English work to give a detailed account of the use of modern diamond core-drills in searching for mineral deposits. The work contains much information of a practical character, including particulars of the cose of apparatus and of working." Nature. FIELD TESTING FOR GOLD AND SILVER. A Practical Manual for Prospectors and Miners. By W. H. MERRITT, M.N.E. Inst. M.E., A.R.S.M., c. With Photographic Plates and other Illustrations. Fcap. Svo, leather. [Just Published. Net 5/O "As an instructor of prospectors' classes Mr. Merritt has the advantage of knowing exactly the information likely to be most valuable to the miner in the field. The contents cover all the details of sampling and testing gold and silver ores. The work will be a useful addition to a prospector's kit." Mining Journal. " It gives the gist of the author's experience as a teacher of prospectors, and is a book which no prospector could use habitually without finding it pan out well." Scotsman. THE PROSPECTOR'S HANDBOOK. A Guide for the Prospector and Traveller in search of Metal-Bearing or other Valuable Minerals. By ]. W. ANDERSON, M.A. (Camb.), F.R.G.S., Author of "Fiji and New Caledonia." Eighth Edition, thoroughly Revised and much Enlarged. Small crown Svo, cloth, 3/6 ! or, leather, pocket-book form, with tuck. [Just Published. 4/6 " Will supply a much-felt want, especially among Colonists, in whose way are so often thrown many mineralogical specimens the value of which it is difficult to determine." Engineer. " How to find commercial minerals, and how to identify them when they are found, are the leading points to which attention is directed. The author has managed to pack as much practical detail into his pages as would supply material for a book three times its size. Mining- Journal. 20 CROSBY LOCK WOOD SON'S CATALOGUE. THE METALLURGY OF SILVER. A Practical Treatise on the Amalgamation, Roasting, and Lixiviation of Silver Ores. Including the Assaying, Melting, and Refining of Silver Bullion. By M. EISSLER, Author of "The Metallurgy of Gold," &c. Third Edition. Crown 8vo, cloth 1 Q/6 " A practical treatise, and a technical work which we are convinced will supply a long-felt want amongst practical men, and at the same time be of value to students and others indirectly connected with the industries." Mining Journal. " From first to last the book is thoroughly sound and reliable." Colliery Guardian. " For chemists, practical miners, assayers, and investors alike we do not know of any work on the subject so handy and yet so comprehensive." Glasgow Herald. THE METALLURGY OF ARGENTIFEROUS LEAD. A Practical Treatise on the Smelting of Silver-Lead Ores and the Refining of Lead Bullion. Including Reports on various Smelting Establishments and Descriptions of Modern Smelting Furnaces and Plants in Europe and America. By M. EISSLER, M.E., Author of " The Metallurgy of Gold," &c. Crown 8vo, 400 pp., with 183 Illustrations, cloth 1 2/6 " The numerous metallurgical processes, which are fully and extensively treated of, embrace all the stages experienced in the passage of the lead from the various natural states to its issue from the refinery as an article of commerce." Practical Engineer. " The present volume fully maintains the reputation of the author. Those who wish to obtain a thorough insight into the present state of this industry cannot do better than read this volume, and all mining engineers cannot fail to find many useful hints and suggestions in it." Industries. METALLIFEROUS MINERALS AND MINING. By D. C. DAVIES, F.G.S., Mining Engineer, &c., Author of "A Treatise on Slate and Slate Quarrying." Fifth Edition, thoroughly Revised and much Enlarged by his Son, E. HENRY DAVIES, M.E., F.G.S. With about 150 Illustrations. Crown 8vo, cloth 1 2/6 " Neither the practical miner nor the general reader, interested in mines, can have a better book for his companion and his guide." Mining Journal. " We are doing our readers a service in calling their attention to this valuable work." Mining- World. " As a history of the present state of mining throughout the world this book has a real value and it supplies an actua v!an.t."Athenceum. MACHINERY FOR METALLIFEROUS MINES. A Practical Treatise for Mining Engineers, Metallurgists, and Managers of Mines. By E. HENRY DAVIES, M.E., F.G.S. Crown 8vo, 580 pp., with upwards of 300 Illustrations, cloth. 1 2/6 " Mr. Davies, in this handsome volume, has done the advanced student and the manager of mines good service. Almost every kind of machinery in actual use is carefully described, and the woodcuts and plates are good." Athenceum. " From cover to cover the work exhibits all the same characteristics which excite the confi- dence and attract the attention of the student as he peruses the first page. The work may safely be recommended. By its publication the literature connected with the industry will be enriched and the reputation of its author enhanced." Mining Journal. EARTHY AND OTHER MINERALS AND MINING. By D. C. DAVIES, F.G.S., Author of "Metalliferous Minerals," &c. Third Edition, Revised and Enlarged by his Son, E. HENRY DAVIES, M.E., F.G.S With about 100 Illustrations. Crown 8vo, cloth 1 2/6 " We do not remember to have met with any English work on mining matters that contains the same amount of information packed in equally convenient form." Academy. " We should be inclined to rank it as among the very best of the handy technical and trades manuals which have recently appeared." British Quarterly Re-view. BRITISH MINING. A Treatise on the "History, Discovery, Practical Development, and Future Prospects of Metalliferous Mines in the United Kingdom. By ROBERT HUNT, F.R.S., late Keeper of Mining Records. Upwards of 950 pp., with 230 Illustrations. Second Edition, Revised. Super-royal 8vo, cloth 2 2s. " The book is a treasure-house of statistical information on mining subjects, and we know of no other work embodying so great a mass of matter of this kind. Were this the only merit of Mr. Hunt's volume it would be sufficient to render it indispensable in the library of every one interested in the development of the mining and metallurgical industries of this country." MINING, METALLURGY, &> COLLIERY WORKING. 21 POCKET-BOOK FOR MINERS AND METALLURGISTS. Comprising Rules, Formulae, Tables, and Notes for Use in Field and Office Work. By F. DANVERS POWER, F.G.S., M.E. Second Edition, Corrected. Fcap. 8vo, leather. [Just Published. 9/Q "This excellent book is an admirable example of its kind, and ought to find a large sale amongst English -speaking prospect" >rs and mining engineers." Engineering. THE MINER'S HANDBOOK. A Handy Book of Reference on the subjects of Mineral Deposits, Mining Operations, Ore Dressing, &c. For the Use of Students and others interested in Mining Matters. By JOHN MILNE, F.R.S., Professor of Mining in the Imperial University of Japan. Revised Edition. Fcap. Svo, leather . 7/6 '' Professor Milne's handbook is sure to be received with favour by all connected with mining, and will be extremely popular among students." AtJienceum. THE IRON ORES of GREAT BRITAIN and IRELAND. Their Mode of Occurrence, Age and Origin, and the Methods of Searching for and Working Them. With a Notice of some of the Iron Ores of Spain. By J. D. KENDALL, F.G.S., Mining Engineer. Crown 8vo, cloth . . 1 6/O " The author has a thorough practical knowledge of his subject, and has supplemented a careful study of the available literature by unpublished information derived from his own observa- tions. The result is a very useful volume, which cannot fail to be of value to all interested in the iron indust>y of the country.'' Industries. MINE DRAINAGE. A Complete Practical Treatise on Direct-Acting Underground Steam Pumping Machinery. By STEPHEN MICHELL. Second Edition, Re-written and Enlarged, 390 pp. With about 250 Illustrations. Royal Svo, cloth. [Just Published. Net 25/O SUMMARY OF CONTENTS : HORIZONTAL PUMPING ENGINES. ROTARY AND NON- ROTARY HORIZONTAL ENGINES. SIMPLE AND COMPOUND STEAM PUMPS. VERTICAL PUMPING ENGINES. ROTARY AND NON-ROTARY VERTICAL ENGINES. SIMPLE AND COMPOUND STEAM PUMPS. TRIPLE-EXPANSION STEAM PUMPS. PULSATING STEAM PUMPS. PUMP VALVES. SINKING PUMPS, &c., &c. "This volume contains an immense amount of important and interesting new matter. The book should undoubtedly prove of great use to all who wish for information on the sub- ject, inasmuch as the different patterns of steam pumps are not alone lucidly described and clearly illustrated, but in addition numerous tables are supplied, in which their sizes, capacity, price, &c., are set forth, hence facilitating immensely the rational selection of a pump to suit any purpose that the reader may desire, or, on the other hand, supplying him with useful information about any of the pumps that come within the scope of the volume." The Engineer. THE COLLIERY MANAGER'S HANDBOOK. A Comprehensive Treatise on the Laying-out and Working of Collieries, Designed as a Book of Reference for Colliery Managers, and for the Use of Coal Mining Students preparing for First-class Certificates. By CALEB PAMELY, Mining Engineer and Surveyor ; Member of the North of England Institute of Mining and Mechanical Engineers ; and Member of the South Wales Institute of Mining Engineers. With 700 Plans, Diagrams, and other Illustrations. Fourth Edition, Revised and Enlarged, medium Svo, over 900 pp. Strongly bound "| 5 S . SUMMARY OF CONTENTS : GEOLOGY. SEARCH FOR COAL. MINERAL LEASES AND OTHER HOLDINGS. SHAFT SINKING. FITTING UP THE SHAFT AND SURFACE ARRANGEMENTS. STEAM BOILERS AND THEIR FITTINGS. TIMBERING AND WALLING. NARROW WORK AND METHODS OF WORKING. UNDERGROUND CONVEYANCE. DRAINAGE. THE GASES MET WITH IN MINES; VENTILATION. ON THE FRICTION OF AIR IN MINES. THE PRIESTMAN OIL ENGINE; PETROLEUM AND NATURAL GAS. SURVEYING AND PLANNING. SAFETY LAMPS AND FIREDAMP DETECTORS. SUNDRY AND INCIDENTAL OPERATIONS AND APPLIANCES. COLLIERY EXPLOSIONS. MISCEL- LANEOUS QUESTIONS AND ANSWERS. Appendix: SUMMARY OF REPORT OF H.M. COMMISSIONERS ON ACCIDENTS IN MINES. " Mr. Pamely has not only given us a comprehensive reference book of a very high order, suitable to the requirements of mining engineers and colliery managers, but has also provided mining students with a class-book that is as interesting as it is instructive." Colliery Manager. " Mr. Pamely s work is eminently suited to the purpose for which it is intended, being clear, Interesting, exhaustive, rich in detail, and up to date, giving descriptions of the latest machines in every department. A mining engineer could scarcely go wrong who followed this work." Colliery Guardian. "This is the most complete 'all-round' work on coal-mining published In the English language. . . . No library of coal-mining books is complete without it." Colliery Engineer (Scranton, Pa., U.S.A.). 22 CROSBY LOCK WOOD & SON'S CATALOGUE. COLLIERY WORKING AND MANAGEMENT. Comprising the Duties of a Colliery Manager, the Oversight and Arrange- ment of Labour and Wages, and the different Systems of Working Coal Seams. By H. F. BULMAN and R. A. S. REDMAYNE. 350 pp., with 28 Plates and other Illustrations, including Underground Photographs. Medium Svo, cloth. [Just Published. 1 5/Q " This is, indeed, an admirable Handbook for Colliery Managers, in fact it is an indispensable adjunct to a Colliery Manager's education, as well as being a most useful and interesting work on the subject for all who in any way have to do with coal mining. The underground photographs are an attractive feature of the work, being very lifelike and necessarily true representations of the scenes they depict." Colliery Guardian. " Mr. Bulman and Mr. Redmayne, who are both experienced Colliery Managers of great literary ability, are to be congratulated on having supplied an authoritative work dealing with a side of the subject of coal mining which has hitherto received but scant treatment. The authors elucidate their text by 119 woodcuts and 28 plates, most of the latter being admirable reproductions of photographs taken underground with the aid of the magnesium flash-light. These illustrations are excellent." Nature. COAL AND COAL MINING. By the late Sir WARINGTON W. SMYTH, F.R.S., Chief Inspector of the Mines of the Crown. Eighth Edition, Revised and Extended by T. FORSTER BROWN, Mining Engineer, Chief Inspector of the Mines of the Crown and of the Duchy of Cornwall. Crown Svo, cloth. [Just Published. 3/6 " As an outline is given ot every known coal-field in this and other countries, as well as of the principal methods of working, the book will doubtless interest a very large number of readers." Mining Journal. NOTES AND FORMULAE FOR MINING 5TUDENT5. By JOHN HERMAN MERIVALE, M.A., Late Professor of Mining in the Durham College of Science, Newcastle-upon-Tyne. Fourth Edition, Revised and Enlarged. By H. F. BULMAN, A.M.Inst.C.E. Small crown Svo, cloth. 2/6 "The author has done his work in a creditable manner, and has produced a book that will be of service to students and those who are practically engaged in mining operations." Engineer. INFLAMMABLE GAS AND VAPOUR IN THE AIR (The Detection and Measurement of). By FRANK CLOWES, D.Sc., Lond., F.I.C., Prof, of Chemistry in the University College, Nottingham. With a Chapter on THE DETECTION AND MEASUREMENT OF PETROLEUM VAPOUR by BOVERTON REDWOOD, F.R.S.E., Consulting Adviser to the Corporation of London under the Petroleum Acts. Crown Svo, cloth. Net 5/O " Professor Clowes has given us a volume on a subject of much industrial importance . . . Those interested in these matters may be recommended to study this book, which is easy of compre- hension and contains many good things." The Engineer. "A book that no mining engineer certainly no coal miner can afford to ignore or to leave unread." Mining- Journal, COAL & IRON INDUSTRIES of the UNITED KINGDOM. Comprising a Description of the Coal Fields, and of the Principal Seams of Coal, with Returns of their Produce and its Distribution, and Analyses of Special Varieties. Also, an Account of the Occurrence of Iron Ores in Veins or Seams ; Analyses of each Variety ; and a History of the Rise and Progress of Pig Iron Manufacture. By RICHARD MEADE. Svo, cloth . . 1 8s. "Of this book we may unreservedly say that it is the best of its class which we have ever met. ... A book of reference which no ona engaged in the iron or coal trades should omit from his library." Iron and Coal Trades Review. ASBESTOS AND ASBESTIC. Their Properties, Occurrence, and Use. By ROBERT H. JONES, F.S.A., Mineralogist, Hon. Mem. Asbestos Club, Black Lake, Canada. With Ten Collotype Plates and other Illustrations. Demy Svo, cloth. [Just Published. 1 6/O " An interesting and invaluable work." Colliery Guardian. GRANITES AND OUR GRANITE INDUSTRIES. By GEORGE F. HARRIS, F.G.S., Membre de la Socie'te' Beige de Geologic, Lecturer on Economic Geology at the Birkbeck Institution, &c. With Illus- trations. Crown Svo, cloth 2/6 " A clearly and well-written manual for persons engaged or Interested in the granite industry. " Scotsman. TRAVERSE TABLES. For use in Mine Surveying. By W. LINTEBN, Mining Engineer. Crown Svo, cloth. [Just Published. Net 3/O ELECTRICITY. ELECTRICAL ENGINEERING, fi-c. 23 ELECTRICITY, ELECTRICAL ENGINEERING, &c. SUBMARINE TELEGRAPHS. Their History, Construction, and Working. Founded in part on WUNSCHEN- DORFF'S " Traite de Telegraphic Sous-Marine," and Compiled from Authorita- tive and Exclusive Sources. By CHARLES BRIGHT, F.R.S.E. Super-royal 8vo, about 780 pp., fully Illustrated, including Maps and Folding Plates [Just Published. Net 3 3 S . " There are few, if any, persons more fitted to write a treatise on submarine telegraphy than Mr. Charles Bright. The author has done his work admirably, and has written in a way which will appeal as much to the layman as to the engineer. This admirable volume must, for many years to come, hold the position of the English classic on submarine telegraphy." Engineer. " This book is full of information. It makes a book of reference which should be in every engineer's library." Nature. " Mr. Bright's interestingly written and admirably illustrated book will meet with a welcome reception from cable men." Electrician. "The author deals with his subject from all points of view political and strategical as well as scientific. The work will be of interest, not only to men of science, but to the general public. We can strongly recommend it." Athenaum. " The work contains a great store of technical information concerning the making and work- ing of submarine telegraphs. In bringing together the most valuable results relating to the evolu- tion of the telegraph, the author has rendered a service that will be very widely appreciated." Morning Post. THE ELECTRICAL ENGINEER'S POCKET-BOOK. Consisting of Modern Rules, Formulae, Tables, and Data. By H. R. KEMPE, M.Inst.E.E., A.M.Inst.C.E., Technical Officer Postal Telegraphs, Author of "A Handbook of Electrical Testing," " The Engineer's Year-Book," &c. Second Edition, thoroughly Revised, with Additions. With numerous Illus- trations. Royal 32mo, oblong, leather 5/O " It is the best book of its kind." Electrical Engineer. " The Electrical Engineer's Pocket-Book is a good one." Electrician. " Strongly recommended to those engaged in the electrical industries." Electrical Review. ELECTRIC LIGHT FITTING. A Handbook for Working Electrical Engineers, embodying Practical Notes on Installation Management. By J. W. URQUHART, Electrician, Author of "Electric Light," &c. With numerous Illustrations. Third Edition, Revised, with Additions. Crown 8vo, cloth. [Just Published. 5/Q " This volume deals with what may be termed the mechanics of electric lighting, and is addressed to men who are already engaged in the work, or are training for it. The work traverses a great deal of ground, and may be read as a sequel to the same author's useful work on ' Electric Light.' " Electrician. " Eminently practical and useful. . . . Ought to be in the hands of every one In charge of an electric light plant." Electrical Engineer. ELECTRIC LIGHT. Its Production and Use, Embodying Plain Directions for the Treatment of Dynamo-Electric Machines, Batteries, Accumulators, and Electric Lamps. By J. W. URQUHART, C.E. Sixth Edition, Revised, with Additions and 145 Illustrations. Crown 8vo, cloth. [Just Published. 7/6 "The whole ground of electric lighting is more or less covered and explained in a very clear and concise manner." Electrical Review. " A vade-mecum of the salient facts connected with the science of electnc lighting." "You cannot for your purpose have a better book than 'Electric Light' by Urquhart." Engineer. DYNAMO CONSTRUCTION. A Practical Handbook for the Use of Engineer-Constructors and Electricians- in-Charge. Embracing Framework Building, Field Magnet and Armature Winding and Grouping, Compounding, &c. With Examples of leading English, American, and Continental Dynamos and Motors. By J. W. URQUHART, Author of " Electric Light," &c. Second Edition, Enlarged. With 114 Illustrations. Crown 8vo, cloth 7/6 " Mr. Urquhart's book is the first one which deals with these matters in such a way that the engineering student can understand them. The book is very readable, and the author leads his readers up to difficult subjects by reasonably simple tests.' 'Engineering A/t ; . on er, Ro yal Commission on Agriculture, 1893, Author of " The Elements of Agriculture," &c. Royal 8vo, 1,100 pp., with over 450 Illustrations, handsomely bound. {Just Published. 1 11s. 60. SUMMARY OF CONTENTS. BOOK I. ON THE VARIETIES, BREEDING, | BOOK VII. ON THE BREEDING, REARING, REARING, FATTENING AND MANAGE- i AND MANAGEMENT OF POULTRY. MENT OF CATTLE. : BOOK VIII. ON FARM OFFICES AND BOOK II. ON THE ECONOMY AND MAN- AGEMENT OF THE DAIRY. BOOK ill. ON THE BREEDING, REARING, AND MANAGEMENT OF HORSES. BOOK iv. ON THE BREEDING, REARING, IMPLEMENTS OF HUSBANDRY. BOOK IX. ON THE CULTURE AND MAN- AGEMENT OF GRASS LANDS. BOOK X. ON THE CULTIVATION AND APPLICATION OF GRASSES, PULSE AND AND FATTENING OF SHEEP. ROOTS. BOOK V. ON THE BREEDING, REARING, BOOK XI. ON MANURES AND THEIR AND FATTENING OF SWINE. APPLICATION TO GRASS LAND AND BOOK VI. ON THE DISEASES OF LIVE CROPS. STOCK. BOOK xil. MONTHLY CALENDARS OF FARMWORK. V* OPINIONS OF THE PRESS ON THE NEW EDITION. " Dr. Fream is to be congratulated on the successful attempt he has made to give us a work which will at once become the standard classic of the farm practice of the country. We believe that it will be found that it has no compeer among the many works at present in existence. . . . The illustrations are admirable, while the frontispiece, which represents the well-known bull, New Year's Gift, owned by the Queen, is a work of art." The Times. "The book must be recognised as occupying the proud position of the most exhaustive work of reference in the English language on the subject with which it deals." Athenizum. "The most comprehensive guide to modern farm practice that exists in the English language to-day- . . . The book is one that ought to be on every farm and in the library of every land owner." Mark Lane Express. " In point of exhaustiveness and accuracy the work will certainly hold a pre-eminent and unique position among books dealing with scientific agricultural practice. It is, in fact, an agricul- tural library of itself. "North British Agriculturist. " A compendium of authoritative and well-ordered knowledge on every conceivable branch of the work of the live stock farmer; probably without an equal in this or any other country." Yorkshire Post. FARM LIVE STOCK OF GREAT BRITAIN. BY ROBERT WALLACE, F.L.S., F.R.S.E., &c., Professor of Agriculture and Rural Economy in the University of Edinburgh. Third Edition, thoroughly Revised and considerably Enlarged. With over 120 Phototypes of Prize Stock. Demy 8vo, 384 pp., with 79 Plates and Maps, cloth. . . 1 2/6 "A really complete work on the history, breeds, and management of the farm stock of Great Britain, and one which is likely to find its way to the shelves of every country gentleman's library." The Times. " The latest edition of ' Farm Live Stock of Great Britain ' is a production to be proud of, and its issue not the least of the services which its author has rendered to agricultural science." Scottish Farmer. "The book is very attractive, . . . and we can scarcely imagine the existence of a farmer who would not like to have a copy of this beautiful and useful work." Mark Lane Express. NOTE=BOOK OF AGRICULTURAL FACT5 & FIGURES FOR FARMERS AND FARM STUDENTS. By PRIMROSE McCoNNELL, B.Sc., Fellow of the Highland and Agricultural Society, Author of " Elements of Farming." Sixth Edition, Re-written, Revised, and greatly Enlarged. Fcap. 8vo, 480 pp., leather. [Just Published. 6/O SUMMARY OF CONTENTS : SURVEYING AND LEVELLING. WEIGHTS AND MEASURES. MACHINERY AND BUILDINGS. LABOUR. OPERATIONS. DRAINING. EMBANKING. GEOLOGICAL MEMORANDA. SOILS. MANURES. CROPPING. CROPS. ROTATIONS. WEEDS. FEEDING. DAIRYING. LIVE STOCK. HORSES. CATTLE. SHEEP. PIGS. POULTRY. FORESTRY. HORTICULTURE. MISCELLANEOUS. " No farmer, and certainly no agricultural student, ought to be without this multum-in-parro manual of all subjects connected with the farm.." North British Agriculturist. " This little pocket-book contains a arge amount of useful information upon all kinds of agri- cultural subjects. Something of the kind has long been wanted." Mark Lane Express. "The amount of information it contains is most surprising ; the arrangement of the matter is so methodical although so compressed as to be intelligible to everyone who takes a glance through i:s pages. They teem with information." Farm and Home. 44 CROSBY LOCKWOOD A- SON'S CATALOGUE. BRITISH DAIRYING. A Handy Volume on the Work of the Dairy- Farm. For the Use of Technical Instruction Classes, Students in Agricultural Colleges and the Working Dairy- Farmer. By Prof. J. P. SHELDON. With Illustrations. Second Edition, Revised. Crown 8vo, cloth. [ Just Published. 2/6 " Confidently recommended as a useful text -book on dairy fanning." Agricultural Gazette. " Probably the best half-crown manual on dairy work that has yet been produced." North, British Agriculturist. " It is the soundest little work we have yet seen on the subject." The Times. MILK, CHEESE, AND BUTTER. A Practical Handbook on their Properties and the Processes of their Produc- tion. Including a Chapter on Cream and the Methods of its Separation from Milk. By JOHN OLIVER, late Principal of the Western Dairy Institute, Berkeley. With Coloured Plates and 200 Illustrations. Crown 8vo, cloth. 7/6 " An exhaustive and masterly production. It may be cordially recommended to all students and practitioners of dairy science. North British Agriculturist. " We recommend this very comprehensive and carefully-written book to dairy-farmers and students of dairying. It is a distinct acquisition to the library of the agriculturist." Agricultural Gazette. SYSTEMATIC SMALL FARMING. Or, The Lessons of My Farm. Being an Introduction to Modern Farm Practice for Small Farmers. By R. SCOTT BURN, Author of " Outlines of Modern Farming," &c. Crown 8vo, cloth. ..'.... 6/O "This is the completes! book of its class we have seen, and one which every amateur farmer will read with pleasure, and accept as a guide. " Field. OUTLINES OF MODERN FARMING. By R. SCOTT BURN. Soils, Manures, and Crops Farming and Farming Economy Cattle, Sheep, and Horses Management of Dairy, Pigs, and Poultry Utilisation of Town-Sewage, Irrigation, &c. Sixth Edition. In One Vol., 1,250 pp., half-bound, profusely Illustrated 1 2/O FARM ENGINEERING, The COMPLETE TEXT=BOOK of. Comprising Draining and Embanking ; Irrigation and Water Supply ; Farm Roads, Fences and Gates ; Farm Buildings ; Barn Implements and Machines ; Field Implements and Machines ; Agricultural Surveying, &c. By Professor JOHN SCOTT. In One Vol., 1,150 pp., half-bound, with over 600 Illustrations. 12/O " Written with great care, as well as with knowledge and ability. The author has done his work well; we have found him a very trustworthy guide wherever we have tested his statements. The volume will be of great value to agricultural students." Mark Lane Express. THE FIELDS OF GREAT BRITAIN. A Text-Book of Agriculture. Adapted to the Syllabus of the Science and Art Department. For Elementary and Advanced Students. By HUGH CLEMENTS (Board of Trade). Second Edition, Revised, with Additions. i8mo, cloth 2/6 "It is a long time since we have seen a book which has pleased us more, or which contains such a vast and useful fund of knowledge." Educational Times. TABLES and MEMORANDA for FARMERS, GRAZIERS, AGRICULTURAL STUDENTS, SURVEYORS, LAND AGENTS, AUCTIONEERS, &c. With a New System of Farm Book-keeping. By SIDNEY FRANCIS. Fifth Edition. 272 pp., waistcoat -pocket size, limp leather . . . -1/6 " Weighing less than i oz., and occupying no more space than a match-box, it contains amass of facts and calculations which has never before, in such handy form, been obtainable. Every operation on the farm is dealt with. The work may be taken as thoroughly accurate, the whole of the tables having been revised by Dr. Fream. We cordially recommend it." Bell's Weekly Messenger. THE ROTHAMSTED EXPERIMENTS AND THEIR PRACTICAL LESSONS FOR FARMERS. Part I. STOCK. Part II. CROPS. By C. J. R. TIPPER. Crown 8vo, cloth. [Just Published. 3/6 " We have no doubt that the book will be welcomed by a large class of farmers and others interested In agriculture." Standard. AGRICULTURE. FARMING, GARDENING, &>c. 45 FERTILISERS AND FEEDING STUFFS. A Handbook for the Practical Farmer. By BERNARD DYER, D.Sc. (Lond.) With the Text of the Fertilisers and Feeding Stuffs Act of 1893, &c. Third Edition, Revised. Crown 8vo, cloth. [Just Published. 1 /Q " This little book is precisely what it professes to be' A Handbook for the Practical Farmer.' Dr. Dyer has done fanners good service in placing at their disposal so much useful information in so intelligible a form." The Times. BEES FOR PLEASURE AND PROFIT. A Guide to the Manipulation of Bees, the Production of Honey, and the General Management of the Apiary. By G. GORDON SAMSON. With numerous Illustrations. Crown 8vo, cloth "I/O BOOK-KEEPING for FARMERS and ESTATE OWNERS. A Practical Treatise, presenting, in Three Plans, a System adapted for all Classes of Farms. By JOHNSON M. WOODMAN, Chartered Accountant. Second Edition, Revised. Crown 8vo, cloth 2/6 " The volume is a capital study of a most important subject." Agricultural Gazette. WOODMAN'S YEARLY FARM ACCOUNT BOOK. Giving Weekly Labour Account and Diary, and showing the Income and Expenditure under each Department of Crops, Live Stock, Dairy, &c., &c. With Valuation, Profit and Loss Account, and Balance Sheet at the End of the Year. By JOHNSON M. WOODMAN, Chartered Accountant. Second Edition. Folio, half-bound Net 7/6 " Contains every requisite form for keeping farm accounts readily and accurately." Agriculture.' THE FORCING GARDEN. Or, How to Grow Early Fruits, Flowers and Vegetables. With Plans and Estimates for Building Glasshouses, Pits and Frames. With Illustrations. By SAMUEL WOOD. Crown 8vo, cloth 3/6 " A good book, containing a great deal of valuable teaching.' Gardeners' Magazine. A PLAIN GUIDE TO GOOD GARDENING. Or, How to Grow Vegetables, Fruits, and Flowers. By S. WOOD. Fourth Edition, with considerable Additions, and numerous Illustrations. Crown 8vo, cloth 3/6 " A very good book, and one to be highly recommended as a practical guide. The practical directions are excellent." Athenaum. MULTUM-IN-PARVO GARDENING. Or, How to Make One Acre of Land produce .620 a year, by the Cultivation of Fruits and Vegetables ; also, How to Grow Flowers in Three Glass Houses, so as to realise 176 per annum clear Profit. By SAMUEL WOOD, Author of " Good Gardening, " &c. Sixth Edition, Crown 8vo, sewed . . . 1/O "We are bound to recommend it as not only suited to the case of the amateur and gentle- man's gardener, but to the market grower." Gardeners' Magazine. THE LADIES' MULTUM-IN-PARVO FLOWER GARDEN. And Amateur's Complete Guide. By S. WOOD. Crown 8vo, cloth . 3/6 " Full of shrewd hints and useful instructions, based on a lifetime of experience." Scotsman. POTATOES: HOW TO GROW AND SHOW THEM. A Practical Guide to the Cultivation and General Treatment of the Potato. By J. PINK. Crown 8vo 2/O MARKET AND KITCHEN GARDENING. By C. W. SHAW, late Editor of Gardening Illustrated. Cloth . . 3/6 "The most valuable compendium of kitchen and market-garden work published." Farmer. 46 CROSBY LOCK WOOD & SON'S CATALOGUE, AUCTIONEERING, VALUING, LAND SURVEYING, ESTATE AGENCY, &c. INWOOD'S TABLES FOR PURCHASING ESTATES AND FOR THE VALUATION OP PROPERTIES, Including Advowsons, Assurance Policies, Copyholds, Deferred Annuities, Freeholds, Ground Rents, Immediate Annuities, Leaseholds, Life Interests, Mortgages, Perpetuities, Renewals of Leases, Reversions, Sinking Funds, &c., &c. 26th Edition, Revised and Extended by WILLIAM SCHOOLING, F.R.A.S., with Logarithms of Natural Numbers and THOMAN'S Logarithmic Interest and Annuity Tables. 360 pp., Demy 8vo, cloth. {Just Published. Net 8/O " Those interested in the purchase and sale of estates, and in the adjustment of compensation cases, as well as in transactions in annuities, life insurances, &c., will find the present edition of eminent service." Engineering. " This valuable book has been considerably enlarged and improved by the labours of Mr. Schooling, and is now very complete indeed." Economist. " Altogether this edition will prove of extreme value to many classes of professional men in saving them many long and tedious calculations." Investors' Review. THE APPRAISER, AUCTIONEER, BROKER, HOUSE AND ESTATE AGENT AND VALUER'S POCKET ASSISTANT. For the Valuation for Purchase, Sale, or Renewal of Leases, Annuities, and Reversions, and of Property generally ; with Prices for Inventories, &c. By JOHN WHEELER, Valuer, &c. Sixth Edition, Re-written and greatly Extended by C. NORRIS, Surveyor, Valuer, &c. Royal 321110, cloth . . . 5/O "A neat and concise book of reference, containing an admirable and clearly-arranged list of prices for inventories, and a very practical guide to determine the value of furniture, &c. " Standard. " Contains a large quantity of varied and useful information as to the valuation for purchase, sale, or renewal of leases, annuities and reversions, and of property generally, with prices for inventories, and a guide to determine the value of interior fittings and other effects." Builder. AUCTIONEERS: THEIR DUTIES AND LIABILITIES. A Manual of Instruction and Counsel for the Young Auctioneer. By ROBERT SQUIBBS, Auctioneer. Second Edition, Revised and partly Re-written. Demy 8vo, cloth 1 2/6 " The standard text-book on the topics of which it treats." Athentzum. "The work is one of general excellent character, and gives much information in a com- psndious and satisfactory form." Builder. " May be recommended as giving a great deal of information on the law relating to auctioneers, in a very readable form." Law Journal. " Auctioneers may be congratulated on having so pleasing a writer to minister to their special needs." Solicitors' Journal. THE AGRICULTURAL VALUER'S ASSISTANT. A Practical Handbook on the Valuation of Landed Estates ; including Example of a Detailed Report on Management and Realisation; Forms of Va'uations of Tenant Right ; Lists of Local Agricultural Customs ; Scales of Compensation under the Agricultural Holdings Act, and a Brief Treatise on Compensation under the Lands Clauses Acts, &c. By TOM BRIGHT, Agricul- tural Valuer. Author of "The Agricultural Surveyor and Estate Agent's Handbook." Third Edition, Revised and further Enlarged Crown 8vo, cloth. {Just Published. Net 6/O " Full of tables and examples in connection with the valuation of tenant-right, estates, labour, contents and weights of timber, and farm produce of all kinds." Agricultural Gazette. "An eminently practical handbook, full of practical tables and data of undoubted interest and value to surveyors and auctioneers in preparing valuations of all kinds." Farmer. POLE PLANTATIONS AND UNDERWOODS. 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Net 7/6 " An exceedingly useful book, the contents of which are admirably chosen. The classes for whom the work is intended will find it convenient to have this comprehensive handbook accessible for reference." Live Stock Journal. "It is a singularly compact and well informed compendium of the facts and figures likely to be required in estate work, and is certain to prove of much service to those to whom it is addressed. " Scotsman. THE LAND VALUER'S BEST ASSISTANT. Being Tables on a very much Improved Plan, for Calculating the Value of Estates. With Tables for reducing Scotch, Irish, and Provincial Customary Acres to Statute Measure, &c. By R. HUDSON, C.E. New Edition. Royal 32mo, leather, elastic band . . . . . . . . 4 O " Of incalculable value to the country gentleman and professional man." Farmers' Journal. THE LAND IMPROVER'S POCKET-BOOK. Comprising Formulas, Tables, and Memoranda required in any Computation relating to the Permanent Improvement of Landed Property. 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A Handy-Book of the Principles of Law and Equity. With a Concise Dictionary of Legal Terms. By A BARRISTER. Thirty-seventh Edition, carefully Revised, and including New Acts of Parliament of 1899. Com- prising the London Government Act, 1899; Sale of Food and Drugs Act, iSQQ ', Infectious Diseases Notification Act, I8QQ ; Small Dwellings Acquisition Act, iSQQ ; Commons Act, 1800; besides the Benefices Act, i8<)8 ; Marriage Act, i8qS ; Inebriates Acts, i8q8 and i8q<); Criminal Evidence Act, iSQS', Vaccination Act, i8qS, &c. Judicial Decisions during the year have also been duly noted. Crown 8vo, 750 pp., strongly bound in cloth. Ut Published. 6/8 V* This Standard Work of Reference forms A COMPLETE EPITOME OF THE LAWS OF ENGLAND, comprising (amongst other matter) ; THE RIGHTS AND WRONGS OF INDIVIDUALS LANDLORD AND TENANT VENDORS AND PURCHASERS LEASES AND MORTGAGES PRINCIPAL AND AGENT PARTNERSHIP AND COMPANIES MASTERS, SERVANTS AND WORKMEN CONTRACTS AND AGREEMENTS BORROWERS, LENDERS AND SURETIES SALE AND PURCHASE OF GOODS CHEQUES, BILLS AND NOTES BILLS OF SALE BANKRUPTCY RAILWAY AND SHIPPING LAW- LIFE, FIRE, AND MARINE INSURANCE ACCIDENT AND FIDELITY INSURANCE CRIMINAL LAW PARLIAMENTARY ELECTIONS COUNTY COUNCILS DISTRICT COUNCILS PARISH COUNCILS MUNICIPAL CORPORATIONS LIBEL AND SLANDER PUBLIC HEALTH AND NUISANCES COPYRIGHT, PATENTS, TRADE MARKS HUSBAND AND WIFE DIVORCE- INFANCY CUSTODY OF CHILDREN TRUSTEES AND EXECUTORS CLERGY, CHURCH- WARDENS, &c. GAME LAWS AND SPORTING INNKEEPERS HORSES AND DOGS TAXES AND DEATH DUTIES FORMS OF AGREEMENTS, WILLS, CODICILS, NOTICES, &c. 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