ELMS ELECTRIC 8 HYDRAULIC (5/ieir CONSTRUCTION CARESOPERATION THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES GIFT OF John S.Prell ELEVATOES HYDRAULIC%ELECTEIC A Complete Hand Book containing Full Descriptions and Illustrations of the Mech- anism of All the Modern Types of Electric and Hydraulic Elevators : : : ALSO INSTRUCTIONS REGARDING THEIR CARE AND OPERATION THE DANGER INCURRED BY CARELESS HANDLING IS CLEARLY SET FORTH-A SERIES OF QUESTIONS AND ANSWERS FOLLOWS. Designed for the Use of Engineers and Operators BY CALVIN F. SWINGLE Author of "Encyclopedia of Engineering," "Twentieth Century Hand Book for Engineers and Electricians," "Examination Questions for Marine and Stationary Engineers." CHICAGO FREDERICK J. DRAKE & COMPANY PUBLISHERS COPYRIGHT 1910 BY FREDERICK J. DRAKE & Co. INTRODUCTION Library sr Literature treating upon the subject of Elevators, either electric or hydraulic is extremely scarce. Even the manu- facturers themselves appear to be chary about issuing cir- cular matter descriptive of the various devices and appar- ratus that they build for the propulsion of Elevators. It is therefore with a view of assisting the engineer who is responsible for their care and safe condition, and the opera- tors whose duties are to handle elevators, that this little volume is sent forth. A study of its contents cannot fail to be of the greatest benefit to those interested, for the rea- son that the principles involved in the construction and operation of the various types of elevators are clearly set forth, and explained in language at once explicit, and to the point. Special efforts have been put forth to make the book a valuable guide and helper to elevator men. Each type of elevator is clearly illustrated in detail, and the action of the working parts so plainly described that a man does not require to be an expert in such matters in order to comprehend their principles. A complete cate- chism of Questions and Answers follows at the close of the subject matter. This catechism includes not only a thorough drill regard- ing the construction and care of elevators and their neces- sary adjuncts, but it also treats upon correct, and incor- rect, safe, and unsafe methods to be pursued in their opera- tion 733217 Uf 6r Mechanical Engine^ SAN FRANCISCO CAL. . Elevators Electric and Hydraulic As the majority of stationary engineers, especially in large cities and towns, have more or less to do with ele- vators, either electric or hydraulic, the author deems it fitting and proper that a section should be devoted to this subject. Therefore, the construction and operation of electric and hydraulic elevators will be taken up in order, and although the subject-matter will have to be somewhat condensed for want of space, still the leading types, including the numer- ous improvements which have been developed during the past ten years will be illustrated, and the mechanism de- scribed. OTIS TRACTION ELEVATOR. Tn the Otis traction elevator the working parts have been reduced to the simplest possible elements. The elevator engine, a view of which is presented in Fig. 380, consists essentially of a motor traction driving sheave, and a brake pulley, the latter enclosed with a pair of powerful spring actuated, electrically released brake shoes, all compactly grouped, and mounted on a heavy iron bed plate. Instead of the high speed motor used with the geared electric elevator, a, slow speed shunt-wound motor designed especially for the service is used. The armature shaft which is of high tensile steel, of unusually large diameter serves merely as a support for the load, and on it are mounted the brake pulley and the traction driving sheave. 11 12 Steam Engineering The actual drive from the armature to the sheave is effect- ed through the engagement of projecting arms on each, cushioned by rubber buffers, thus entirely eliminating all tortional strains to the shaft, and the use of keys. In this machine all intermediate gearing between motor and driv- ing member is dispensed with, by the use of the slow speed motor, and the result is, that the starting, accelerating, re- tarding and stopping events are each, and all, remarkably even and quiet. FIG. 380 OTIS TRACTION ELEVATOR The driving cables, from one end of which the car is supported, while to the other end the counterweight is attached, pass partially around the traction driving sheave in lieu of a drum, continuing under an idler leading sheave, thence again around the driving sheave, thereby forming a complete loop around these two sheaves, which arrange- ment results in the necessary tractive effort for lifting the car. One of the striking advantages resulting from this Otis Traction Elevator 13 arrangement of cables, and the method of driving the same is the decrease in traction which follows the striking on the bottom of the shaft of either the car or the counterweight, and the consequent minimizing of the lifting power of the machine, until normal conditions are resumed. Inasmuch as in any properly constructed elevator the parts are so arranged that the member (car or counterweight) which is at the bottom of the shaft must strike and come to rest before the other member can possibly come in contact with the overhead work, it will readily be seen that the above mentioned decrease in tractive effort is a valuable, and effective safety feature inherent in this type of elevator. The controller is so designed in connection with the motor, that the initial retarding of the car in bringing the same to stop is independent of the brake, the latter being requisitioned to bring the car to a final positive stop and to hold it at the landings. The motor is also governed in such a way, electrically, as to prevent its attaining any excessive speed with the car no matter what the load in same may be. In designing the controlling equipment, one of the fea- tures demanding greatest consideration, in view of the very high speed at which the cars run, is the automatic retard- ing of their speed and the final positive stopping of same, automatical!}', at the upper and lower terminals of travel. This result is very satisfactorily attained with the installa- tion, in the elevator hatchway, of two groups of switches located respectively at the top and bottom of the shaft, eacli switch in the series being opened one after another, as the car passes, resulting in a reduction of speed until the open- ing .of the final switch brings the car to a positive stop, applying the brake. This operation is entirely independent 14 Steam Engineering of the operator in the car and is effective even though the car operating device be left in the full speed position. Another feature of security of the greatest interest and importance is provided in the Otis Patented Oil Cushion Buffers. (See Fig. 381.) These are placed in the hoistway, one under the car and one under the counterweight, and ' FIG. 381 OTIS PATENTED SPRING RETURN OIL BUFFER are arranged to bring either the car or the counterweight to a positive stop, through the telescoping of the buffer this occurring at a carefully calculated rate of speed, which is regulated by the escape of oil from one chamber of the buffer to another. The buffers have been proven capable by test of bringing *, loaded car safely to rest from full Otis Traction Elevator 18 speed, and in this respect are unique among elevator safety features of comparatively low cost. The usual safety devices installed in connection with modern high grade apparatus are used with this type of elevator, including speed governors, wedge clamp safety devices for gripping the rails in case of the car attaining excessive speed, and potential switches. OTIS GEARED TRACTION ELEVATOR. The modern adaptation, in the Otis Traction Elevator, of the traction principle for elevator service which utilizes the patented feature of operating the car by means of driv- FIG. 382 OTIS DIRECT CURRENT TRACTION MACHINE FOE OVERHEAD INSTAL- LATION ing the cables direct from the motor without the interven- tion of retarding rigging, showed so conclusively the merits of that principle that the question naturally arose as to the 16 Steam Engineering feasibility of employing this method of drive in the low speed machines as well. The result was the introduction of what is commercially known as the Otis Geared Trac- tion Elevator which embodies many of the good points of its larger contemporary. It might be well to state here that the traction principle is neither new nor experimental, as is instanced by its use in the familiar type of carriage hoist, this being in reality a low duty hand power traction elevator driven by means of a hemp rope; also this method of drive has been em- ployed on dumb-waiters for some time. However, as ap- plied to the high speed passenger machines used in our tall office buildings, it must be referred to as a comparatively new and improved development of former types. The Geared Traction machine is similar in appearance to the standard drum machine, except that a multi-grooved driving sheave is mounted in place of the drum, and a non- vibrating idler leading sheave takes the place of the vibrat- ing sheave necessary on the drum type. The car and the counterbalance weight hang directly from the driving sheave one from either end of the cables in precisely the same manner as with the Otis Traction Elevator ; the neces- sary amount of traction being obtained by the extra turn resulting from passing around the idler sheave. The machines are built in two classes, double screw, and single screw, depending upon the duty required. The double screw machine is designed for the heavier duties, and the gearing consists of a right and left hand worm, see Fig. 383, accurately cut from a solid forging. This worm, coupled directly to the electric motor, runs submerged in oil and meshes with two large bronze gear wheels, which in turn mesh with each other. The effect of the three-point drive thus obtained, in conjunction with Three Point Drive 17 the right and left hand thread, is the entire elimination of end thrust on the worm shaft a most desirable feature. The complete gear is fully protected in an oil tight iron case and is well lubricated in every part. To the forward gear wheel, that is the one furthest from the motor, there is bolted the iron buffer-neck, or what might be termed the driving spider. It is constructed in such a way that the use of keys is unnecessary to effect the drive, inasmuch, as the flange of the buffer-neck is bolted with through bolts directly to the bronze gear wheel near FIG. 383 THREE POINT DBIVE its periphery, and by means of four extending arms on its opposite end engages with similar arms on the driving sheave. A mechanically strong and perfect drive is thus obtained. The shaft passing through the driving sheave and buffer-neck serves merely as a support for the moving loads and is subject to absolutely no tortional strains. In order to protect the gears and elevator car from possible vibrations, large rubber buffers are placed under slight compression between the arms of the sheave and those of the buffer-neck. 18 Steam Engineering The machine is equipped with a mechanically applied, and electrically released double shoe brake. The shoes are applied against a pulley of ample diameter and width to dissipate any heat generated, and serves as a coupling be- tween the motor shaft and the worm shaft. The brake shoes are normally bearing against the pulley with a pressure corresponding to the compression of the two helical springs. When current is admitted to the solenoid brake magnet, and then only, the action of the springs for the time is overcome, so that the shoes are released.. It will be seen, therefore, that the brake will apply with full force should a failure of current occur; resulting in an immediate stop of the elevator. The motor is compound wound, and runs at about eight hundred revolutions per minute at full car speed and load. The series field is used only at starting to obtain a highly saturated field in the shortest possible time, and is then short-circuited, leaving the motor to run as a plain shunt wound type. In stopping, a comparatively low resistance field is thrown across the armature, providing a dynamic brake action and a gentle slowing down of the car, the mechanical brake being called upon only to effect the final stop and to hold the load at rest. Resistance in series with this "Extra Field," as it is called, is controlled by magnets which de- pend, in their operation, on the speed of the armature. It is therefore evident that the dynamic, or retarding effect of the field is proportional to the speed, and therefore to the load in the elevator car, hence good stops under all conditions are easily obtained. To meet the demands in districts where alternating cur- rent is in use, the same apparatus described is furnished Alternating Current Machine 11) except that the direct current motor and controller give place to an alternating current motor and controller. The alternating current machines are made in two classes also, single and double screw. The cut, Fig. 384, repre- sents a double screw machine designed for basement in- FIG. 384 OTIS ALTERNATING CURRENT DOUBLE SCREW TRACTION MACHINE Designed for Basement Installations stallations. The brake is slightly different in appearance but performs the same functions as does the direct current brake. The safeties used on the Otis Traction Elevators are found on the geared, traction elevators. The main differ- ence between the two machines being the ability to use on 20 Steam Engineering the latter a small high speed motor with gearing, instead of the large, slow speed and more expensive motor of the Otis Traction Elevator. Fig. 385 MAGNET CONTROLLER Fig. 385 shows the Otis electric magnet controller, and Fig. 386 shows the standard oar switch. With this operating device the current is automatically and gradually admitted to the motor, enabling the operator to start and stop the car without shock or jar. This controlling device is con- Magnet Controller 21 structed to secure the motor against damage by any over- load, or excess of current; these features are automatic in their operation, are independent of the operator in the car, and are designed to prevent more current being ad- mitted to the motor than is required to do the maximum work of the elevator. FIG. 36 OTIS LEVER CAR SWITCH Electro magnets are employed throughout, thereby elim- inating the use of all rheostats, sliding contacts, or other easily deranged devices. The contacts and wearing parts in the controlling mechanism are of ample dimensions to meet the severe conditions, and exacting requirements of elevator operation and control, Careless Operation. The waste of power caused by the careless operation of electric elevators is well worth consid- 22 Steam Engineering eration. The following timely suggestions are quoted from an article by C. M. Bipley in the September, 1909, issue of Power : "An electric passenger elevator driven by a 30-horse- power motor on a 220-volt circuit is generally fused for 150 amperes. Assuming that it requires four seconds for the car to gain its maximum speed, and that electric service costs 10 cents per kilowatt-hour, the cost of merely start- ing the elevator will figure out as follows : 150X220X4=132,000 watt-seconds; 132,000^3600=36.6 watt-hours or 0.0366 kilowatt hour; 0.0366X10=0.366 cent, or over a third of a cent. "In a building with, let us say, one elevator, serving six floors continually for eight hours, this waste in power would be considerable if the operator had to make one unneces- sary start on each trip, or two unnecessary starts for each round trip. If this car made 84,000 round trips in a year, the power waste would cost over $60. And if this average held good in buildings with ten elevators instead of one, with 24-hour service instead of 8-hour service, and with 20 stories instead of six stories, the loss would amount to something over $3,000. The wear and tear on switch con- tacts, controller contacts, controller magnets, commutator, armature, steel worm, bronze gear or gears, thrust plates, ball bearings, armature bearings, drum-shaft bearings, the car cables, the counterweight cables and the back-drum cables are all materially increased also by increased starting." Table 49 gives some interesting and instructive data regarding the starting and running current, fuse capacity, etc., of various sized motors for Otis elevators. Overhead Installation FIG. 387 DOUBLE WORM AND GEAR ELECT KIC ELEVATOR, OVERHEAD INSTAL- LATION Steam Engineering -punoj 'anbaoj, lOWt-INN w eo w Basement Installation FIG. 388 SINGLE WORM AND GEAB ELECTRIC ELEVATOB, BASEMENT INSTAL- LATION 26 Steam Engineering- In addition to the waste of power caused by unnecessary starts, there is the tremendous strain to which the appar- atus and cables are subjected when the car is suddenly stopped on the down trip; there is also the liability of burning out armatures by hasty reversals. Most elevator controllers are designed now so that the current cannot be sent through the motor in the reverse direction until the armature has ceased revolving. But there are many con- trollers still in use which are not so equipped, and motors operated with such controllers can easily be damaged by suddenly reversing the car switch before the motor has stopped revolving. If an elevator operator reverses his switch to the "down" position before the motor has fully ceased rotating in the "up" direction, the effective voltage at the armature terminals will be practically the sum of the line voltage and the counter electro-motive force of the armature, instead of the difference between the line voltage and the counter electro-motive force, or almost twice the line voltage, with nothing to oppose it but the very low resistance of the armature winding and connections. This would result in a flow of an enormous current sufficient to burn up the armature in short order if the safety fuses did not melt promptly. HYDRAULIC ELEVATORS. The mechanism of a hydraulic elevator consists of a cylinder and piston, the piston being connected by one or more piston rods to a cross-head which carries the sheaves over which run the lifting cables from which the car is suspended. By means of suitable valves, and con- trolling mechanism operated from the car, water, under pressure from compression, or gravity tank systems, or Hydraulic Elevators FIG. 389 from street mains where sufficient pressure is available, is caused to flow inio, and out of the cylinder, thus causing 28 Steam Engineering the piston to move from one end of the cylinder to the other, and back again. This motion of the piston and cross-head to and fro imparts motion to the lifting cables which pass over sheaves at the top of the elevator hatchway, and which hold in suspension the car, thus moving it up or down, according as the water flows into or out of the water cylinder. The motion of the piston transmitted to the cable is multiplied to a greater or less degree, according to the design of the elevator, by being caused to pass over sheaves designed for that purpose. Thus the ratio of increase in speed may be anywhere from 2 to 1, to 12 to 1, to meet the requirements due to the nature of the service, whether freight or passenger. The height of the building also controls in a large measure the speed, for instance in very tall buildings the elevators may be geared as high as 12 to 1. The cylinders of hydraulic elevators are made either ver- tical, or horizontal depending upon local conditions. If the floor space is restricted, vertical cylinders are used, but in cases where space above the basement floor for the accommodation of vertical machines cannot be easily ob- tained, it is the usual practice to place horizontal cylin- ders in the basement. Vertical cylinders are usually geared three and four to one, although ratios of from two to one, up to six to one are quite common. Fig. 389 presents a view of a low pressure vertical cylin- der hydraulic elevator geared two to one. The cut shows the general arrangement of the mechanism, from base- ment to top sheave. This type of hydraulic elevator is operated by the movement of the hand rope n, which passes around a sheave at the side of the valve chamber, and moves the valve by means of a rack and pinion gear. Hydraulic Elevators 29 Rope n then passes under two small sheaves at the bottom of the elevator hatchway, and from thence up to the top of the hatchway, and over another small sheave. One side of this hand rope passes through the car, and by pulling this side up the operator causes the car to descend, and by pulling the rope down the car will ascend. Near the top, and bottom of the hatchway two balls m and m' are placed upon the hand rope. They are large enough to prevent their passing through the openings in the floor, and roof of the car through which the hand rope passes. When the car ascending strikes the upper ball m, the latter is carried up with the car, thus pulling up the hand rope, and moving the control valve back to the stop position. Should the car fail to stop, the valve will be carried past the stop position, which will connect both ends of the cylinder, and the car will start to descend. If, however, every part is properly adjusted, this reversal of the motion of the car cannot occur, because under such conditions, the car will stop when the valve is closed. If by any mishap the car should run away, and go beyond the normal limit of its travel, the control valve would be slightly opened in the opposite direc- tion, just sufficient to develop a retarding force and thus stop the car. The action is the same when the car approaches the bottom, as it will then strike ball m', which will be carried down, thereby closing the operating valve. Balls m and m' are in fact automatic top and bottom limit stops, and constitute one of the most valuable safety devices with which elevators are equipped. Another valuable device is the speed limit, which usually consists of stops mounted at some convenient point in the hatchway, and set above and below balls m and m', so as to limit the distance through which the latter can be moved. 30 Steam Engineering In some cases additional stop balls are used, on account of its not being convenient to place stops to act directly upon m and m'. The positions of these stops which limit the amount of opening of the valve, are determined experi- FIG. 390 mentally when the elevator is installed. The movement of the car is kept steady by guides M, M, Fig. 389. In the construction shown in Fig. 389 these guides are made of hard wood. At the top of the car adjustible shoes are Safety Devices 31 provided, which slide freely against the guides. At the bottom the car is guided by jaws formed in a safety device, or "safety" as it is termed. It is made of hard wood blocks, the dimensions varying from 4 inches thick by 11 inches wide in the smaller sizes, to 5 in. x 15 in. in the larger sizes. The jaws of this safety are reinforced with massive iron castings, and on one side are provided with a wedge that can be adjusted in position by means of screws, and on FIG. 391 the opposite side with another wedge that can be forced between the guide and the jaw to stop the car if one of the lifting ropes breaks, or the car attains an excessive velocity from any cause. By reference to Fig. 390, and also to Fig. 391, which shows one end of the safety device, its construction and operation will be clearly understood. In Fig. 391 the governor rope rod L is shown only in the end elevation. Referring to Fig. 390 it will be seen that 33 Steam Engineering the two lifting ropes that run down to either side of the car are connected with the ends of a rocking lever C. This lever C, as shown in Fig. 391, is pivoted at D', hence if either one of the lifting ropes breaks, the end of the lever it is attached to will drop down. The shaft II which extends under the car from one side to the other, carries at its ends a lever L' which, when raised lifts the wedge N and forces it into the space between the guide M and the side of the jaw of the safety plank. Whichever way the lever C may be tilted by the breaking of one of the lifting ropes, it will rotate shaft H and lever L' in the proper direction to throw up wedges N, thereby locking the car against the stationary guides M. The levers on shaft H are sufficiently long to strike the guides M, when raised high enough, and are sharp at the ends so that they will cut into the guides. It might be thought that if the wedge N is only raised far enough to catch in the space between the guide M and the safety-plank jaw it would be forced upward so tightly as to stop the car without further assistance. This would be the case if the wedge had a sufficiently long taper, but if it were so proportioned, it would require an enormously strong jaw to resist the bursting strain ; moreover, the car would be so tightly wedged that it would require a greater force to release it than could be easily obtained. With the wedges of the proportions used, it is necessary to make the lever that lifts the wedge so that it will dig into the guide, and as the car moves down through, say, a foot or two in coming to a stop, the lever shaves the side of the guide, thereby not only forcing the wedge tighter against the guide, but producing an additional retarding force. When a car is caught by the safety, all that is neces- Safety Devices 33 eary to release it is to start in the upward direction, and the force exerted by the lifting cylinder is enough to overcome the friction of the wedges against the guides. In the foregoing it is shown how this safely acts, provid- ing one of the ropes breaks. Elevator cars, however, seldom drop when one of the ropes breaks, but frequently attain FIG. 392 a very high velocity when the ropes do not break, and on that account it is necessary to arrange the safety so that it will act when the speed reaches a certain stage regard- less of the cause of increased velocity. This is accom- plished by means of the Otis safety governor, shown mounted on one of the overhead beams in Fig. 389, and in detail in Fig. 392. This device is driven by the rope L, 34 Steam Engineering which is made fast to one end of lever G' as shown in Fig. 389. The spring that holds G' is strong enough to keep the lever in its normal position and rotate the safety gov- ernor at a velocity proportional to the speed of the car. Eeferring to Fig. 392 it will be seen that the governor may be adjusted by means of the spring on the spindle, to act at any desired velocity. The governor driving rope passes through the clamping jaws H H', and when the governor speed becomes great enough to lift the rod Z and throw the jaws together, the rope will be clamped. Then, as the rope cannot move, the outer end of the lever G' on the safety plank will be held stationary as the car descends ; hence, the shaft H will be rotated, throwing the safety wedges N into action to stop the car. It is evident that the car can descend only as far as the upward movement of the end of lever G' and the compression of the spring on L will permit, before the rope will be compelled to slide through the clamps H, H' of the governor. As the distance through which the spring can be compressed, plus the move- ment of the end of G' is only a few inches, it is evident that unless the car is stopped very short, the rope L must break if it cannot slide through clamps H, H'. The dis- tance in which the car will stop is always considerably more than the compression of the spring plus the movement of the end of G'; hence, while it is necessary for H H' to clamp the rope tight enough to move G', the pressure must not be so great as to prevent the rope from slipping. For the same reason, in order to make the safety governor reliable it is necessary that the operating rope shall be in just as good condition as the elevator lifting ropes. The failure to inspect this rope properly, and make sure that it is at all times in perfect condition has been a prolific cause of accidents. Safety Devices 35 The jaws of the safety plank and the wedge N should be kept clean and in proper adjustment at all times. As the 36 titeam Engineering guides M have to be kept well lubricated, it can be easily seen that if the safety jaws are neglected they will soon become clogged with a mixture of grease and dust, and this may give a considerable trouble by causing the wedge to stick to the side of the guide and thus go into action when everything else is running properly. The wedge N, and the adjusting wedge on the opposite side of the guide, will gradually wear away. For this reason the latter should be set up as often as required to keep the proper amount of clearance between the guide, and the safety jaw. If the clearance is too great, the wedge N is liable to not catch firmly when called into action, and if the clearance is too small, the safety is liable to act when not required. The operating valve shown in Fig. 389 is the same in principle as the one shown in section in Fig. 393, but it has several details of construction not shown in the latter. Its design is shown more in detail in Fig. 394, which is a sectional elevation of the valve, and casing. The casing is made in three parts marked 7, 8 and 9. Part 7 forms the top, and provides a dome, into which the rack 6 on the end of the valve rod can rise as the valve is lifted by the rotation of the pinion on the end of the shaft A. This shaft carries at its outer end the hand rope sheave shown at the side of the valve in Fig. 389. The parts 7 and 8 are divided at the center of the shaft A, and form a bearing for the latter. The lower part 9 which is the valve casing proper, has ports 10 and 11 for connection with the lower end of the circulating pipe, and the lower end of the cylinder, in the manner indicated in Fig. 393. That portion into which the circulating pipe is connected forms a separate casting in Fig. 389, and the casing 9 is bolted to it. Port 12 in part 9 of the valve casing is for the purpose of connecting Safety Devices 37 FIG. 394 38 Steam Engineering with the pressure-water supply if for any reason it is not desired to have this connection made in the circulating pipe. The valve casing is lined with brass tubing 4 and 3. Lining 4 is simply for the purpose of providing a smooth surface for the cup packing of V to slide against. Lining 3 is provided for the purpose of making ports of sucli a character that the cup packings of V may be able to slide over them freely. If the ports were large openings, the packings could not pass over them, because on the up movement they would be caught by the edges of the ports. With the brass linings this trouble is overcome by perforating the brass with a large number of small holes, about one-quarter of an inch in diameter. The combined area of the holes is much larger than would be required in a single port, this increase in opening being provided so as to reduce the friction of the water running through the holes by reducing the velocity of flow. The pressure of the water tends to force the valve piston V up, and the other piston V down, and as both pistons are the same in diameter, the valve is balanced. Never- theless the force required to move the valve is considerable, owing to the friction of the cup packings, caused by the pressure of the water acting upon the entire surface of the leather in contact with the brass linings of the valve casing. On this account the pinion on the shaft A, through which the valve is moved, is made very small, while the hand rope sheave is large about 20 inches in diameter so that while the valve travels a few inches in either direction the hand rope has to be pulled through a distance of from two to four feet, according to the size of the valve and the speed nf car. For high car speeds the hand rope movement is in- creased, so that the automatic top and bottom stops may Operating Valve 39 be able to arrest the movement of tbe car without making the stop abruptly. Reference to Fig. 394 will show that the lower head that clamps packing 2 is made tapering. This is done in order to prevent too quick a closure of the outlet from the lower end of the cylinder when the valve is moved down to stop the car on the up trip; otherwise the stop would be too abrupt. Even with this precaution it is possible for the operator to close the valve too quickly; therefore a check valve is inserted in the passage connect- ing the valve casing with the cylinder. This check is directly under the lower end of the circu- lating pipe, so that if the operator closes the valve too sud- denly the descent of the piston within the cylinder will not be arrested instantly, but the piston will slowly continue its movement and gradually force the water under it to pass through the relief check valve, into the circulating pipe, and thus into the top end of the cylinder. If the operator moves the hand rope so quickly on the down trip as to produce a violent stop, the piston will continue to rise in the cylinder, and the water above it which cannot pass to the lower end of the cylinder on account of the valve being closed, will be forced back through the inlet pipe I to the pressure tank. In this case, as no water can pass into the lower end of the cylinder, the continued upward move- ment of the piston causes it to leave the water, and thus a vacuum is formed underneath it. This vacuum together with the tank pressure on top of the piston soon arrests the movement of the car, but the stop is not so sudden. One objection to having the con- nection from cylinder to pressure tank through the inlet pipe I is, that if for any reason the pressure in the tank- should drop to zero, owing to the starting of a bad leak, the water in the top end of the cylinder could immediately 40 Steant Engineering FIG. 395 Operating Valve 41 run out with such freedom that if the car should happen to be at, or near the top of the hatch' way it would attain a dangerous speed by the time it reached the bottom. But by locating the pressure tank on the roof of the building the danger from this source is obviated, for the reason that the flow of the water from the cylinder would then be against a pressure due to the elevation of the tank, and to this may be added the pressure of the atmosphere, for the reason that the valve being closed, no water can pass into the lower end of the cylinder, and as the piston moves up, a vacuum is formed under it thus tending to retard its motion. The result is that the combined pressures are sufficient to hold the car within safe speed limits. When the pressure tank is located in the basement, the danger above referred to is avoided by using a valve of the type shown in Figs. 395 and 396. Fig. 395 shows the casing, and Fig. 396 the valve. The difference between this valve and that of Fig. 394 is that it is provided with an additional piston V", see Fig. 396, which is called the throttle valve. When this valve is used, the inlet pipe from the pressure tank is attached to the port 12. When the elevator is stopped, the throttle valve V" is directly opposite the port 12, and thus obstructs the flow of water from the port 10. It will be seen that a groove is turned in V" at the center line. In addition the valve is not made a perfect fit in the casing, and the clear- ance thus afforded is sufficient to permit water to pass by in as large an amount as may be required to prevent a too sudden stoppage of the car should the operator close the valve too quickly. Another advantage is, that in case the tank pressure should fail, the flow of water past this clear- Steam Engineering FIG. 396 ance is retarded sufficiently to prevent a dangerous s in the descent of the car. Operating Valve 43 When the valve is moved in either direction to set the car in motion, water passes from port 12 to port 10 through side ports 14. A portion of this water passes directly from 12 to 14, and the other portion passes around the upper lining 4, through circular passages 13, and thence down FIG. 397 into 14, as indicated by the arrows. In this way sufficient opening around the throttle valve is afforded even when the port of the operating valve piston V is only slightly open. The passages 13 and the connection between the ports 14 and 10 are not easily made out from Fig. 395, but 44 Steam Engineering the arrows indicate the course of the water, and these make the construction more easily understood. Fig. 397 which is a section through the passages 13, taken at right angles to Fig. 395 will serve to illustrate more fully the construc- tion. The pistons used in vertical hydraulic elevators are made in several designs, some being arranged so as to be packed from the upper end, and others so as to be packed from the lower end. Fig. 397 shows one of the latest designs of pis- tons arranged to be packed from the lower end of the cylin- der, which appears to be the favorite type now. The draw- ing shows a section through the complete pistoti, with pack- ing in place, also a section of the cylinder C. Ordinary square packing is used, and this is held in position by a follower secured by six bolts. Fig. 398 shows the body of the piston only. The parts P and P" are made to fit the cylinder, but the intervening section is cut away on opposite sides, so as to afford space for the ends of the piston-rods and their fastening nuts. The top and bottom parts of the piston are connected by the pillars I and I. In packing these pistons it is necessary to be careful not to press the packing in too tight,- as there is danger of burst- ing the cylinder by so doing, and even if this much damage is not done, the friction caused by the excessive pressure may be so great as to prevent the car from attaining its full velocity. If a hard packing is used, and this is forced into place dry and very tight, the chances are that when it becomes well soaked it will expand enough to burst the cylinder. Bursting hydraulic-elevator cylinders is not a very rare occurrence, and when it does occur it is due to too great pressure of the piston packing against the sides of the cylinder. Piston Packing Fio. 398 46 Steam Engineering Referring to Fig. 389, it will be noticed that there are two piston rods, E. This construction was adopted in the early days of hy- draulic elevators partially to increase the safety of the apparatus, but principally to prevent the traveling sheave B from twisting around. The ropes tend to hold the sheave from twisting, but they will not prevent slight movements, while the double piston-rods will. Xow and for several years past, however, the frame of the traveling sheave has been made in the form of a crosshead running in stationary guides, thus effectually preventing any side movement of the sheave. With this construction the main benefit of the double piston-rods is additional safety; while it is possible for one rod to break or become loose, it is practically im- possible for both to give way at the same time. The arrangement of the cylinder C, the circulating pipe K, and the valve V, in Fig. 389, is the same as in the dia- gram Fig. 393, even the inlet I being similarly situated. The small pipe c is for the purpose of carrying off the drip from the upper side of the top cylinder head, ordinarily, and also for the purpose of draining the water from the upper end of the cylinder, in cases where it is necessary to run the piston to the top of the cylinder to renew or adjust the packing. Some cylinders are arranged to be packed from the upper end and others from the lower end, the latter design being the one generally used in modern ma- chines. As will be noticed, the pipe c connects at the bot- tom of the cylinder with other pipes that connect to the valve chest and the lower end of the cylinder. All these pipes are either to carry off the drip or to draw water from the various parts of the cylinder and valve chest when desired. Globe valves are placed in the drainage pipes so as to keep them closed normally. Operating Devices 47 Counterbalance. Generally a portion of the counter- balance is placed on top of the piston, so that in such ma- chines the counterbalance weight is divided into three parts, one being within the cylinder, one in the traveling sheave frame, and one constituting the independent counter- balance. Operating Devices. In order if possible to avoid the uncertainty of operation in connection with the hand rope in high speed elevators, lever, and wheel operating devices have been developed, and to make these devices operative and reliable, the operating valves have been somewhat modi- fied in design. The main valve, controlling the flow of water into, and out of the cylinder, varies in diameter from 3 inches in small machines, to 7 or more inches in the large sizes. Fig. 399 shows the lever device for operating, a modern high speed hydraulic elevator. The lever L is shown located in the car. The movement of this lever to one side or the other rocks the horizontal lever M, and this motion causes the sheave P mounted on the frame I to rotate through a small angle. The rotation of P is trans- mitted to P' through the rope k, and the rotation of P' actuates the valves in a manner that will be presently ex- plained. Ropes m m, n n pass around sheaves N N N N located at top and bottom of the elevator hatchway, as is clearly shown. The ends m m are fastened to the ends of the lever M but the sides n n are not connected with it, although in the illustration they look as if they were. The side n that runs up from the right-hand side N sheave at the bot- tom passes over the N" sheave at the left-hand side at the top of the elevator hatchway. These two N sheaves at the top are mounted upon a frame I which is arranged so as to hold the sheaves firmly in the horizontal position, but 48 Steam Engineering FIG. 399 Operating Devices 49 allows them to revolve freely around the studs upon which they are mounted. The frame I is suspended from a rope that passes over the two small sheaves resting on top of the overhead heams. The end of this rope extends downward, outside of the elevator hatchway, and has a weight sus- pended from it so as to hold the ropes m m, n n, with the proper tension. Upon the larger sheave P are mounted the lower N N sheaves. If the right-hand end of lever M is depressed, the right-hand loop formed by the rope n m will be low- ered, while the left side end will be raised, and as a conse- quence the right side lower N sheave will swing downward while the left side one will swing upward. Thus the rope k will be pulled with the upper side moving from left to right, and sheave P' will be rotated in the direction in which the hands of a clock move. This arrangement of ropes for transmitting the motion of lever L to sheave P' is called the running rope system. There is another way of accomplishing the result with sta- tionary ropes, the upper ends of these being attached to the upper frame I and the lower ends to the sides of sheave P, or to the ends of a lever secured to this sheave. In this arrangement the rope that is fastened to the right-hand side of sheave P is secured to the left side of the upper frame I. The sheaves N N N N are placed upon the ends of lever M and each rope passes over one sheave at one end, and under another sheave at the other end of M. This is the standing rope system. For both systems there are sev- eral modifications, but the results are the same in each case, viz., to transmit the motion of lever L to sheave P'. Valve v controls the flow of water into and out of the hydraulic cylinder. This valve is actuated by a piston T located in the enlarged portion of the valve chamber, and 50 Steam Engineering which is larger in diameter than valve v; consequently if water under pressure is admitted to the space between T and v, the pressure of the water upon the larger area of piston T will cause it to move up, provided there is no pressure on its top side. If water under pressure is ad- mitted to both sides of piston T, it will be balanced and will exert no force to move the valve in either direction. Valve v will, however, have the pressure acting upon its upper side, while the only pressure acting against its lower side will be atmospheric pressure, or that of the tank into which the water is discharged. Consequently the valve will move downward. Water is admitted to the space above piston T through a small pilot valve at h which is connected with the pressure pipe through pipe g, while pipe f connects it with the space above T. When the car is at rest, pilot valve h is in a position to close the ports connected with pipes g and f, and also pre- vents the escape of water into the larger pipe connecting the lower end of the pilot valve chamber with the main discharge pipe. Under these conditions, the water in the main valve chamber above piston T cannot escape unless valve h leaks. When sheave P' is rotated in a clockwise direction, the crank on the end of the shaft will draw down the connecting rod j, and as valve h can move much easier than main valve v and piston T the latter will remain stationary, while h will be depressed. This movement of h will uncover the ports connecting with pipes g and f, thus establishing a through connection between the pressure pipe and the space above T and the latter will be forced down- ward, carrying with it throttle valve V which will uncover the port connecting with pipe G, and also move the main valve v far enough down to uncover the upper edge of the port connecting with the lower end of the cylinder, thus Operating Devices 51 opening a communication between the two ends of the main cylinder. Under -these conditions the weight of the elevator car which acts to pull piston F upward will set the latter in motion, and the water in the upper end of the cylinder E will be forced down through pipe G and through the valve chamber, around valve V into the lower end of the cylinder. The pipe G is called a circulating pipe, as one of its objects is to provide a path through which the water may circulate between the top and the bottom of the cylinder E. As the action just explained takes place when the ele- vator car descends, it will be seen that, for the down trip, no water is drawn from the pressure tank. To run the car upward, the sheave P' is rotated counter clockwise by swinging the car lever L in the opposite direction. When P' is so rotated, the crank on the end of the shaft will push connecting rod j upward, and thus pull on rod i and thereby lift the pilot valve h. The upward movement of h uncovers the port that connects with pipe f, but keeps that connecting with pipe g closed, so that the water con- fined in the valve chamber above T can now escape through pipe f, and the lower end of the pilot valve chamber into the discharge pipe. In this way the pressure acting on the top side of T is removed, and the pressure acting on the bottom side forces the valves up, owing, as has been already explained, to the difference in area between T and valve v. The upward movement of valve v opens communi- cation between the port running to the lower end of the hydraulic cylinder, and the discharge pipe, thus permitting the water in the lower end of the cylinder to escape through the discharge pipe. This upward movement of the valves also raises throttle valve V and allows the water in the pressure pipe free access to the port connecting with pipe 52 Steam Engineering G, thus admitting a new supply of water under pressure to the space above the piston in the hydraulic cylinder. Under these conditions the water acting upon the top side of piston F in conjunction with the vacuum formed under the piston by the escape of the water into the discharge pipe, provides the force that depresses the piston and thereby lifts the car. Upon the rate of flow with which the water can enter, or pass out of the cylinder will depend the velocity with which the piston will move, and this rate of flow is evidently dependent upon the extent to which the valves are opened. If the operator in the car desires to run at a slow speed, he moves lever L a short distance from the central posi- tion; for a higher speed, he moves it further from the center, and for the highest velocity, he moves it as far as it will go. Now suppose L is moved a short distance only, then sheave P will be rotated through a short angle, imparting a correspondingly small movement to connecting rod j. Suppose j is depressed, thus opening the connection be- tween pipes g and f water will begin to flow into the space above T as soon as pilot valve h moves down far enough to uncover the ports connecting with pipes g and f and draw down the end S of lever Q. As j will now be stationary, it will act as a fulcrum, and R will be lifted. This movement will continue until pilot valve h is raised sufficiently to cover the ports connecting with pipes g and f, which will stop the flow of water into the space above T. It will thus be seen that, after pilot valve h has been moved by the rotation of the sheave P', main valve v, and piston T also begin to move, and as they move, the pilot valve is returned to stop position. If pilot valve h is moved but a short distance from stop position, Operating Devices 53 piston T and valve v will have a correspondingly short distance to move to return the pilot valve to stop position. The amount of opening given to pilot valve h depends upon the distance the car lever L is moved. If for a short dis- tance, the opening will be but a small fraction of its travel, and the main valve will open a correspondingly short dis- tance, and vice versa. As water is practically incompres- sible, it is apparent that if lever L be too quickly moved to the central position when the car is moving at a high rate of speed, the motion will be arrested with a violent jerk. In order to prevent such action, means are provided whereby the water may find an outlet, if the valve is closed too suddenly. If the sudden stop occurs on the downward trip of the car, which is the up-stroke of piston F, the water will leak by the throttle valve V and flow back into the pressure pipe, and will continue to flow until the car has come to a stop. If the throttle valve Y were not provided, the water would escape too freely, back into the pressure pipe, and as a result the car could not be stopped in a very short distance; hence, the object of valve V is to provide means to prevent a too sudden stop of the car on the down trip, and at the same time not to permit the car to run farther than is necessary to make a gradual stop. Valve V is not water-tight, as has already been explained (see Fig. 396), and its throttling action begins gradually. Should the car be stopped too suddenly on the up-trip, the water in the lower end of cylinder E will be forced through valve d at the bottom of pipe G, and the mo- mentum of the moving parts will be expended in com- pressing the spring that holds valve d to its seat. Fig. 399 has been reduced in length, but it shows in detail all of the mechanism of a modern type vertical cylinder hy- Steam Engineering FIG. 400 Cylinders 55 draulic elevator, with running rope or standing rope con- trol. Other methods of control besides those already de- scribed are in use, mainly in private dwellings and other places where an operator is not employed. These consist of magnetic controllers for operating the pilot valve by means of push buttons, the magnets being operated by current from the incandescent light circuit, or if such a circuit is not available, the current is derived from pri- mary, or storage batteries. Horizontal Cylinder. The principal difference between the vertical, and the horizontal cylinder types of hydraulic elevators lies in the fact that in the one type the cylinder stands in a vertical position, while in the other it is placed horizontally. The principles governing the operation of the valve mechanism are practically the same in both cases, outside of a few details which will be explained. Fig. 400 shows the general arrangement of a horizontal cylinder hydraulic elevator, including pump and pressure tank. The type here illustrated and described is the Crane push- ing type elevator, there being two distinct classes of hori- zontal hydraulic elevators, viz., the pushing and pulling types. Referring to Fig. 400, the stationary sheaves and rear end of the cylinder will be seen close to the hatch- way. The main valve which controls the admission and release of the water to and from the cylinder is located at K, and is automatically operated by the movement of the pilot valve L, the latter being actuated by the rocking of shaft M, which is done by means of rods m m con- nected with a running rope system operated by the lever in the car. An automatic stop valve is located at R simi- lar in design to that described in connection with vertical cylinder machines. This valve is actuated by the median- 56 Steam Engineering ism at N, which is set in motion by the movement of the crosshead. Figs. 401, 402 and 403 show the apparatus in detail. FIG. 401 In Fig. 401, which is a side elevation, it will be seen that if lever S is moved in either direction, the rods m m will FIG. 402 cause shaft M to rock, thus moving the pilot valve by means of valve rod I/. Moving the pilot valve will either FIG. 403 open or close main valve K, which will allow the water to flow into, or out of the cylinder, depending upon what direction lever S is moved. Cylinders 57 If the operator fails to return lever S to stop position when the car reaches the top of the hatchway, the frame N will be carried to the right by the motion of the cross - head, and the projecting arm D, Fig. 302, will strike the stop mounted on rod D" connected to the end of the frame. This movement of N will cause a roller at n' to strike lever o', which will move to the right, and pull rod Q with it, and this action will close stop-valve E, which will stop the flow of water into the cylinder, and the car will come to a stop. Should the car be descending, the main piston will be moving to the left, and if lever S is not returned to stop position at the proper time, the automatic stop will act in precisely the same way, except that frame N will be moved to the left instead of to the right. Eeferring to Fig. 403, which is a sectional elevation of the cylinder, piston, sheaves and connecting parts, it will be seen that there is a rubber ring around the piston end of the plunger E, and a similar ring in the crosshead D. A strong buffer frame I is attached to front cylinder head G. The function of these parts is to act as cushions in case the car travels past its normal position at either end. These parts should be adjusted so as to prevent the car, or counterbalance weight from striking the overhead beams in case the automatic stop valve fails to act. Pulling Type. Fig. 404 shows a view of a pulling type of horizontal cylinder hydraulic elevator. This machine is made by the Whittier Machine Company, and its action is as follows : G is the main operating valve, and the pilot valve is located directly above it at J. The automatic stop valve is at H, and is actuated by stop balls N mounted on rope L. These stop balls are moved by coming in contact with an arm attached to the crosshead, which also carries 58 Steam Engineering FIG. 404 THE WHITTIER PULLING MACHINE Whittier Hydraulic Elevator 59 the traveling sheaves D, and shoes E on the crosshead slide within the side guides. The weight P suspended from the chain that travels between two small guide sheaves located just below the valve casing, is for the purpose of bringing the automatic FIG. 405 stop valve to central position as soon as the piston moves away from either end of the cylinder, The shackle bolts for the ropes are shown at Q. The main and the pilot valves of the Whittier machine are shown in detail in Figs. 405 and 406, the first being a o Cylinder Fran Cj Under FIG. 406 plan view and the second a sectional side elevation. Re- ferring to Fig. 405, it will be seen that the operating lever K is pivoted at the point F, so that when actuated by the operating ropes AA' it imparts an end movement to the pilot valve rod C. The ropes AA' are connected with the 60 Steam Engineering operating lever in the car by either a running, or a stand- ing-rope arangement identical with those used for vertical- cylinder elevators. In Fig. 406 the pilot valve rod C is shown connected with the top end of lever D, the latter being pivoted at G. The part B, which holds the pivot G is actuated by the lever K. The supply pipe is connected with the right-hand end of the pilot-valve chamber through the pipe E. If the rod C is moved to the left, high-pressure water will pass through the pilot valve to the end I of the main valve and force the latter to the left, thereby connecting the cylinder with the discharge pipe, when the water will run out and the elevator car descend. The forward movement of the FIG. 407 main valve will carry the lower end of the lever D to the left and the upper end to the right, until the pilot valve is returned to the closed position. If the pilot-valve rod C is moved to the right, the end I of the main valve will be connected with the discharge and the water will escape, then the pressure acting on the piston L will force the valves to the right and connect the supply pipe with the cylinder, which will fill with water from the pressure tank and the car will be forced upward. The movement of the. main valve to the right will carry the lower end of the lever D in the same direction and the upper end to the left, and return the pilot valve to the central position. Double-Decked Machine 61 The pilot valve shown in Fig. 406 is provided with stuffing-boxes at each end to insure tight joints with the valve- rod, but this construction is not used in all the Whittier elevators; in some of them the pilot valve is made as shown in Fig. 407, where the escape of water at the ends is prevented by the use of cup packings. Tho pressure water enters through the port A, the discharge being through the port B; consequently, the cups are set so as to oppose the pressure which is exerted in both di- rections from the port A. Another design of the pulling-type elevator is presented in Fig?. 408, 409 and 410. This is called a "double-decked'-' machine, and is made by Morse, Williams & Co., of Phila- delphia. Why it is called double-decked can be understood from Fig. 408, which is a side elevation and shows two ma- chines placed one over the other. In buildings where floor space is limited, this construction is often adopted, in some cases three and four machines being installed one over an- other. Fig. 409 is a top view of Fig. 408, and Fig. 410 is an end view seen from the right side. In these machine? there is but one piston rod, as at B., Fig. 408. The crosshead is similar to that in the Whittier machine, except that the sides of the end bars are square with the side frame's, instead of in line with the traveling-sheave shaft, as at J, Fig. 410. The guides F are set so that the crosshead shoes a, slide on top of the upper flange, not between the flanges. At the stationary-sheave end of the guides there are shorter guides TJ, which carry a shaft provided with small rollers b, the function of which is to support the ropes running over the upper sides of the sheaves. In Fig. 408 the upper machine is shown with the traveling sheave? close to the stationary sheaves, caused by the car being at Steam Engineering the lower floor of the building. In this machine the sup- porting rollers b' are at the extreme right-hand end of Double-Decked Machine 63 the guides U'. In the lower machine sheaves D are close to the cylinder, as they will be when the elevator car is at the top floor. In this case the supporting rollers b are at the extreme left-hand end of guides U and midway be- FIG. 410 tween the sheaves D and E, the better to support the ropes at the central point. On the upper machine in Fig. 408 a hook 1 mounted on a shaft carried by the guide shoes c' engages a piece e, secured to the part J', as shown in Fig. 410, at the center. At one end of the shaft which carries 64 Steam Engineering hook 1 there is a lever k. When the sheaves D' move to- ward the cylinder, the hook 1 being engaged with lever e, the supporting rollers b' are carried along with the hook 1 until lever k reaches an inclined plane m, up which the rollers slide, causing the shaft to be rotated and hook 1 to be pulled up out of the way of the lever e, the rollers being left in the position of those shown on the lower machine. The supporting roller shaft is kept in line, notwithstanding that it is carried along by the part e acting at the central point, by reason of the guide-shoes c being provided with grooves that fit over the guides IT, as clearly shown in Fig. 410. When the traveling sheaves move forward, the piece e engages hook 1 when the latter is reached, and the roller shaft is carried forward to the end of the guides, as shown at b. These supporting rollers relieve the ropes of considerable strain when the stroke is long, and the traveling sheaves are near the cylinder, but they are of little service in short-stroke machines. The movement of the roller shaft is equal to one-half the stroke of the machine. The Stop and Main Valves. In a machine of the pull- ing type the piston is forced toward the back end of the cylinder on the upward motion of the car. If the auto- matic stop-valve is properly adjusted, it will begin to close at the right time to stop the car even with the upper floor ; but if it is improperly adjusted, the car is likely to run into the overhead beams, therefore buffers g g, faced with rubber cushions h h, are provided. In the machine illus- trated in Fig. 408 the automatic stop-valve does not fit perfectly, and if the main valve is not closed when the car reaches the upper floor, the car will not stop but will slowly move upward until the crosshead brings up against the buffer cushions h h. On the downward trip, if the Stop and Main Valves 65 main valve is. not closed when the car reaches the lower floor, the car will settle gradually until it rests on the bumpers, or the piston strikes the front cylinder head. In Fig. 408 the main valve is located at G and is actuated by a pinion at n which meshes with a rack in the neck-bearing n'. The automatic stop-valve is con- tained within the casing H and is actuated by a rod con- necting with a crank-pin on a crank-disk mounted on the shaft with the sprocket-wheel Q, Figs. 408 and 409. The sprocket-wheel Q is rotated by means of a sprocket mounted on the shaft with sprocket f, Fig. 409, which latter is operated by a chain, the ends of which are affixed to the ends of two square rods, the lower of which is shown at L. Another chain around the sprocket P is connected with the opposite ends of these two rods. To stop the movement of the piston, the stop-valve is actuated to the left. If the traveling sheave is moving toward the cylin- der the actuating bar E attached to the crosshead will strike the stop 1ST and move it to the left, which will set up a counter-clockwise rotation of the sheaves and Q, and this will move the crank-pin and the stop-valve to the left. If the traveling sheave is moving away from the cylin- der, the lower end of bar E will strike the stop N on the square rod L and, by carrying the latter to the right, ro- tate sheaves and Q counter-clockwise in the same direc- tion. The stops N are hook-shaped ; they slide over the side projections on bar E, Fig. 410, and lock with it, with the result that when the elevator is started on the return trip the movement of the crosshead carries the stop X with it, and the automatic stop-valve H is pulled open. When the elevator is started it moves very slowly for a few inches, as only the water that leaks by the automatic stop- valve is available to move it, but as the movement of the JSteam Engineering J FIG. 411 High Pressure Elevators 67 crosshead also operates the valve, the opening of the latter is rapidly increased and the car speed correspondingly ac- celerated. When the bar E has carried the stop N as far as the stop T the releasing lever S strikes the latter and the hook on the stop X is raised so that the bar E may slide by and leave the stop N adjoining the stop T, ready to be struck by the bar E on the next stroke. The actuating stops T are not held on the rod L but on a rod directly in front of it (see Fig. 410), and this rod is secured, so it will not move endwise, in the frame V. Fig. 411 shows a double-deck arrangement of two sepa- rate machines. This grouping of horizontal elevator en- gines is often resorted to for the purpose of economizing space, the machinery for operating two cars occupying the same floor area as that ordinarily required for one. High Pressure Elevators. The types of elevators hither- to discussed belong in the low pressure class, the water pressures used in operating them not exceeding 200 Ibs. per square inch, the average being about 150 Ibs. But the increase in the height of modern office buildings, and the demand for a high car speed have resulted in the develop- ment of high pressure elevators, operating under pressures as high as 700 Ibs. per square inch, and even higher in some cases. The reduction in the size of the machine and piping that can be effected by using this pressure is much greater than would be supposed by those who have not investigated the subject. To give a general idea of how great the re- duction actually is, suppose a low-pressure elevator has a cylinder 16 inches in diameter and works with a pres- sure of 100 pounds. For such a machine the supply pipe would probably be not less than 6 inches in diameter. Sub- fi8 Steam Engineering stitute for this a high-pressure machine working with 800 pounds pressure per square inch; then, if everything el^e remains unchanged, the area of the cylinder will be re- duced to one-eighth, and this will make the diameter a trifle under 5% inches, as compared with the low-pressure cylinder of 16 inches diameter. This is not all the gain that can be made; there can also be effected a great re- duction in the size of the supply pipe, for as only one- eighth of the quantity of water is required, the size of the pipe can be reduced to the same degree as that of the cylin- der, provided the water is to run through it at the same velocity. This reduction would cut the pipe down from 6 inches to a trifle over 2 inches in diameter. These reductions are not exactly what would be made in actual practice, because the frictional loss in the small high-pressure cylinder would not be as great as in the large low-pressure cylinder, and the velocity of the water through the supply pipe could be made greater for the same percentage of loss; this would permit a farther re- duction in the size of the pipe. In practice the gain in this direction is utilized in part to reduce the size of the apparatus, and in part to reduce the loss of energy in forc- ing the water through the pipes. As a result, the loss of energy due to the friction of the water passing through the pipes, lifting cylinder and valves is reduced to about 5 or 6 per cent, whereas in low-pressure machines it run? from, say, 10 to 30 per cent. The change of pressure from 100 to 700 or 800 pounds brings about other changes in the construction of the machine and apparatus and also in the general arrangement of the system. The arrangement of the various parts of a high-pressure system is indicated by the diagram, Fig. 412. This dia- gram shows a machine geared six to one. The cylinder is High Pressure Elevators (10 shown at C, the plunger at P and the traveling sheaves below it; the cylinder is inverted, the plunger being forced downward by the pressure of the water. This construe- Fro. 412 tion is used because the small size of the cylinder makes it impracticable to use a piston and piston-rod, therefore a solid plunger is provided and the pressure acts to push it out of the cylinder. 70 Steam Engineering In Fig. 412 the pump forces water into the lower end of the accumulator, from which a pipe runs to the ijiaiii valve, through which it passes to the pipe A and thence to the lifting cylinder. On the return stroke the water passes out of the cylinder through the pipe A and through the upper end of the main valve to the discharge pipe, which runs up to a tank placed on or near the roof of -the building. The object of this arrangement is to provide a low pressure to operate the pilot valve, which is shown in the diagram just above the main valve. In the first high-pressure elevators made, the pilot valve was operated with water at the same pressure that was used for the lift- ing cylinder, but these valves were not successful, owing to the fact that they had to be very small and the packings would not withstand the wear due to the pinhead jets of water striking them at terrific velocities; in addition, the small holes through which the water passed were soon en- larged so that the valve would not work satisfactorily. With the low-pressure pilot valve there is no trouble. A small tank is provided to receive the discharge from the pilot valve and its actuating cylinder, and this water is returned to the roof tank by means of a small pump as shown in Fig. 412. The Accumulator. The accumulator takes the place of the pressure tank of the low-pressure system. A pressure tank cannot be used with the high-pressure system, owing to the fact that it is troublesome and expensive to pump air against a high pressure, and it is necessary to do this so as to replenish the air that gradually leaks out of the pres- sure tank. Even if there were no difficulty in pumping air into a high-pressure tank, the accumulator would be pref- erable, because with it the pressure depends upon the weight on top of the plunger, not on the height of the The Accumulator 71 water in the cylinder. With a pressure tank the pressure drops as soon as water is drawn out, and it runs up as soon as the outflow stops, consequently the pressure is con- tinually varying. FIG. 413 The arrangement of the entire apparatus of an Otis high- pressure vertical elevator is shown in Fig. 413. This il- lustration shows several parts not represented in. the ele- mentary diagram, Fig. 412. The main pump is at A and 72 Steam. Engineering at B is shown the prime mover, which in this case is an electric motor, although in practice steam power is almost always used. The accumulator is shown at C and the main valve, and pilot valve are at D. From the main valve the water passes to the lifting cylinder through pipe E, passing first through an automatic stop-valve F, thence through pipe G to cylinder H. The plunger is shown at I, and the traveling sheaves at J. The high-pressure water from the accumulator reaches the main valve through pipe K and is discharged from the valve through pipe L which runs up to the tank at the top of the building. Through pipe M, the water returns to the pump A. An air chamber is provided at Q to smooth out any pulsations of the pump that its own air chamber does not subdue! The small pump to return the water discharged from the pilot valve to the roof tank is also shown. It will be noticed in Fig. 413 that the machine proper of a vertical high-pressure elevator is not very elaborate. Fig. 414 shows a sectional, and also a plan view of the main and pilot valves. The pilot valve is at A, and the main valve at C ; B is a motor cylinder, the piston of which moves the main valve. In this construction, the pilot valve is not much smaller in diameter than the main valve, and the motor piston is very much larger than the main valve. The dif- ference in the proportions of these parts as compared with the valves described in connection with low-pressure ma- chines is due to the fact that in the high-pressure system the motor piston is actuated by low-pressure water, so as to make it possible to use a pilot valve of large enough size to be durable. As is shown in Fig. -413, the tank into which the lifting cylinder discharges is placed high enough The Accumulator 73 to give enough pressure to operate the motor piston, and from this tank water passes through the pilot valve A to the cylinder B. If the motor piston were operated hy the high-pressure water, the pilot valve and its port holes would have to be so small that the parts could not be made sufficiently substantial. For this reason water at a pres- FIG. 414 sure of about 80 pounds per square inch is used to operate the motor piston. It might be thought that having to discharge the water in the lifting cylinder against a back pressure of 80 pounds would cause considerable loss, and make the high-pressure system objectionable on the score of low efficiency, but this is not the case because the main pump draws water from 74 Steam Engineering this same discharge tank; therefore, the back pressure against the lifting cylinder acts to help the pump, so that in reality all the work the pump has to do is to force water against a pressure equal to the difference between the pres- sure of the accumulator and that of the discharge tank. The net result is that if the accumulator pressure is 750 pounds, and that of the discharge tank is 80 pounds, the actual pressure against which the pump acts is 750 80 =670 pounds, and the pressure that acts in the lifting cylinder to raise the elevator car is 670 pounds, not taking into account the losses due to friction of the water through the pipes and valves on its way from the accumulator to the Cylinder. Operation of Main and Pilot Valves. The operation of the main and pilot valva in Fig. 414 is as follows: If the operator desires to run the car upward he moves the car lever so as to pull up the rope N' on the right side, thus tilting the rock lever N in a counter-clockwise direc- tion. The levers N and L are secured to the shaft P; hence, the end of L will move down and through the con- necting rod L' will pull down the lever L" ; and the latter, through M, will depress the pilot valve. The center pipe E is connected with the upper discharge tank : hence, water will flow in and through the lower end of the pilot-valve chamber, pass to the lower end of the motor-piston cylin- der B, and raise the piston, the water above the latter pass- ing out into the pilot-valve chamber above the valve, and thence to the pipe D. As the motor-piston rod is connected at both ends by arms J J with the ends of the main valve C, the upward . movement of the piston will lift the main valve, and then the water from the accumulator coming through the pipe I will pass into the center of the main valve through the port S. The port Q will be above the Cylinder and Plunger 75 packing R, so that the water will pass out into the cen- tral pipe H and thence to the lifting cylinder, and by pushing the plunger out of the latter will lift the elevator car. If the rock lever N is tilted in the opposite direction, the pilot valve will be raised, and then water will pass to the upper end of the motor cylinder and depress the pis- ton, thus moving the main valve down so that the water in the lifting cylinder may escape through the ports Q' into the upper end of the main valve and thence through the ports S' to the upper discharge pipe G ; from there it passes to the discharge tank near the top of the building. Cylinder and Plunger. Figs. 415 and 416 show the construction of the plunger, cylinder, and sheaves of the Otis high pressure vertical cylinder elevator. Fig. 415 gives external and sectional views of the cylin- der, the upper end of which is seen at A and the lower end at B. To shorten up the drawing the cylinder is broken at C C. The plunger is indicated by D. Above the cylinder are shown the stationary sheaves held between side frames made of channel iron G, to the lower end of which the cylinder is bolted, as shown at G'. The channel frames G are bolted to a rod H at the upper end, and this is held between beams I that are secured to the wall or floor framing of the building. The traveling sheaves are carried in a crosshead attached to the lower end F of the plunger. The internal construction of the cylinder is shown in the vertical section, which is taken at right angles to the exterior view. The upper end of this drawing shows the way in which the bearings of the stationary sheaves are held between the side frame channel beams G G, and in like manner the lower end shows the construction of the cap F that forms the end of the plunger and the support Steam Engineering FIG. 415 for the traveling-sheave frame. This cap is constructed cup-shaped on its upper side to receive the drip from the Cylinder and Plunger 77 cylinder. The plunger, it will be noticed, does not fit the cylinder throughout its entire length, but only for a short distance at the lower end, where the stuffing-box is lo- cated. The cylinder is held up by the rod H, and is sus- tained against side displacement by means of one or more rings K and the frame J, the construction of both of which can be readily understood from the drawings. The outlet M in Fig. 415 is the pipe connection through which the actuating water enters and passes out of the cylinder. T-bars I' I' to which the frame J is bolted form the guides for the crosshead of the traveling sheaves, and the cylinder is held true with these by means of the frame J so as to keep the plunger and the crosshead guides in line. Fig. 416 shows side, and edge views of the crosshead, the guides, and the traveling sheaves. Fig. 417 shows the speed regulator used in connection with the Otis high pressure type of elevator. This device will not allow the car to attain an excessively high speed under any conditions, for the reason that it depends for its action upon the velocity of the current of water passing through it, and not upon the pressure. The device is con- nected in 'the piping so that the water that flows into or out of the lifting cylinder passes through it. If, when the car is ascending, the water enters through port, 0, and passes out through D, then on the descending trip the water will enter through D and pass out through C. In either case, the water will have to pass through the open- ings, E, in the valve piston, this passage causing a cer- tain amount of loss in pressure dependent entirely upon the velocity of the water through the holes, E. Suppose that, when the car is running at 400 feet per minute, the loss of pressure suffered by the water in 78 Steam Engineering FIG. 417 passing through the piston holes, E, is 20 pounds; then, if the car is running up, and the pressure of the water when it reaches one side of B is 800 pounds, it will be, on Cylinder and Plunger 79 the other side, 780 pounds. If the car is running down and the water is discharging into the delivery tank, a pres- sure of 100 pounds on the cylinder side of B will corre- spond to 80 pounds on the tank side of B; that is to say, in either case the difference in pressure between the two sides of B will be 20 pounds. From the construction of the device, it will be seen that the force with which the piston rod, A, is moved endwise by the difference in the pressure on the opposite sides of B is resisted by the spring, K, so that by properly adjusting this spring, the car can be made to run at any desired speed with the main valve wide open, regardless of the magnitude of the load or whether it is running up or down. Thus it will be seen that, when this speed regulator is provided, the car cannot attain an excessive velocity, even if the operator becomes confused and opens the main valve too wide. In passing from either of the inlets, C or P, into the interior of the cylinder, the water must flow through the small holes in the casing, F. These holes are drilled on spiral lines so that, when B moves in either direction, it covers the holes one at a time, thus gradually closing the outlet. The end movement of B is transmitted to one, or the other of the levers, G, through rod, A, and the move- ment of either lever will compress spring, K. Direct Acting Plunger Type. A direct acting plunger elevator consists of a cylinder set vertically in the ground directly under the car, and of length a few feet greater than the travel of the elevator car. In this cylinder is a plunger of the same length, carrying a car on its upper end. The bottom of the plunger is supported by an in- compressible body of water, and the car cannot descend faster than the water is forced out. 80 Steam Engineering FIG. 418 DIRECT ACTING PLUNGER ELEVATOB Direct Acting Plunger Type 81 The success of this elevator depends largely upon the merits of the operating mechanism. In the installation of this type of hydraulic elevator it is necessary to sink the hole for the reception of the cylinder to a depth equal to the height of the building. Fig. 418 shows the- general arrangement of the Otis direct acting plunger elevator. This illustration is broken at a point between the elevator car and the bottom of the elevator shaft in order to reduce its length, but the part broken away would only show the continuation of the guides, plunger, operating ropes, etc.; all the operating parts of the outfit are shown in the illustration. In plunger elevators, as the full pressure on the end of the plunger acts to lift the car, the diameter of the plunger is much smaller than in the geared types of elevators. The pressure used varies from about 140, to 200 pounds per square inch and the diameter of .the plunger may be from 5 to 7 inches. The cj'linder is made of steel pipe about 2 inches larger in diameter than the plunger, and the hole in the ground is a couple of inches larger than the cylinder. It will thus be seen that the hole in which the cylinder is placed is not very large, so that it can be bored in a manner similar to that employed for driving pipe wells. If the subsoil is earth, a steel pipe lining is pro- vided which is large enough to receive the cylinder. If the hole is drilled in rock, no lining is required. For the cylinder, a number of lengths of steel pipe are turned true on the ends, threaded in a lathe, and joined by sleeve couplings. The upper end of the cylinder is screwed into a cast-iron section which is bored to fit the plunger, and is provided with a stuffing-box and a pipe connection through which the water enters and passes out of the cylinder. The lower end of the cylinder is closed 82 Steam Engineering by means of a suitable cap. The cylinder is coated with a protecting paint and when in position, the space between it and the sides of the hole is filled with sand. For the plunger, a number of lengths of steel pipe are turned true and well polished. The sections are joined by means of long internal sleeves which are so proportioned that the transverse strength of the plunger at the joint is as strong as at any other point. As the elevator car can rise only as high as the plunger travels, it follows that when the rise is 300 feet, the cylin- der must extend down into the earth several feet more than 300, because when the car is at the top of the elevator hatchway the bottom end of the plunger must be some dis- tance below the top end of the cylinder. Furthermore, it is necessary to provide sufficient length of plunger to carry the car a short distance above the upper floor, say, two feet, in order to avoid running the- bottom of the plunger too high up in the cylinder if the elevator should overrun the upper limit of travel. The plunger passes through a stuffing-box at the upper end of the cylinder, and is provided with guide shoes at the lower end to keep it in line and central. Referring to Fig. 418, the car rests upon the upper end of the plunger P, and the latter runs down into the cylin- der C, the upper end of which projects above the ground floor. From the top of the car a number of cables R ex- tend upward and over a sheave S and thence down to a counterbalance W. This counterbalance serves to reduce the pressure required to raise the elevator, and also to reduce the compression stress to which the plunger is subjected. The pipe of which the plunger is made weighs about 22 pounds per foot, so that a plunger 200 feet long will weigh Direct Acting Plunger Type 83 about 4,400 pounds; this is more than the car is likely to weigh, the latter ranging between 3,000 and 4,000 pounds. If the car weighs, say, 3,600 pounds, and the plunger 4,400 pounds, the two combined will weigh 8,000 pounds, and with no counterbalance this weight would have to be raised in addition to the load. Consequently the plunger would be subjected to a compression stress of 3,600 pounds plus the load at the upper end, and 8,000 pounds plus the load at the bottom, the stress increasing from top downward at the rate of 22 pounds per foot. With a coun- terbalance weighing 5,000 pounds, the weight raised will be reduced to 3,000 pounds plus the load, and as the coun- terbalance exceeds the weight of the car by 1,400 pounds, it will actually hold up about one-third of the plunger, from the upper end downward, when the car is empty. When the car is at the bottom of the shaft the plunger is immersed in the water in the cylinder, consequently a portion of its weight is balanced by the water it dis- places. When the car is at the top of the shaft the plunger is out in the air and its weight is not counter- balanced to any extent by the water. This being the case, the weight lifted will be less when the car is at the bottom of its travel than when at the top, the difference being equal to the weight of water displaced by the plunger. By prop- erly proportioning the weight of the cables E, the load lifted can be made equal at all points, for when the car i? at the bottom of the shaft these cables will hang above the car, and thus will offset a portion of the counterbalance W, while when the car is at the top of the shaft the cables will hang above the counterbalance W and balance a por- tion of the weight of the car. The main valve for controlling the movement of the car is shown at V, and the pilot valve at V. The two 84 Steam Engineering valves A and B are the automatic stop or limit valves, A being the top limit and B the bottom. The valve A is actuated by the rope A" which pulls up the lever A' and thereby closes the valve. This rope moves the lever A' through the motion of the elevator car. Looking at the illustration, it will be seen that the rope A" runs over a sheave D mounted on top of the elevator car, and it can also be seen that when the car approaches the upper limit of travel, D begins to put a bend in A" and thereby draws up the lever A'; by the time the car reaches the upper floor, A' will be raised enough to close the valve A. By this arrangement the valve is closed gradually and the car is as gradually brought to a state of rest. The valve B is actuated by the rope B" in precisely the same manner that A is operated by the rope A". The rope B" passes over the stationary sheave D' and under the sheave D" located under the car, and when the latter de- scends near enough to the lower floor, the bend put in the rope B" by the sheave D" will raise the lever B' and grad- ually close the valve B. The pressure water enters through the valve A; hence, at the top landing the automatic stop arrests the movement of the car by shutting off the supply water. When the elevator car descends, the discharge water passes out through the valve B; hence, the bottom limit valve stops the descent of the car by stopping the escape of water from the cylinder. Construction of Cylinder. The construction of the upper end of the cylinder is shown in Fig. 419. This drawing, which is a vertical sectional elevation of the top of the cylinder and plunger, also shows the way in which the plunger is fastened to the under side of, the car, as well as the construction of the plunger. For the purpose of Cylinder Construction 85 FIG. 419 86 Steam Engineering reinforcing the plunger, a steel cable B is strung inside both of its ends fastened to a pin A, located some distant below the center of the plunger, and the loop or bight, a the top of the plunger, is passed around a tightening bloc] ; this block is arranged so as to be drawn up by the bolt 0' to put the desired tension on the rope B. The plunge D is made of as many lengths of piping of the prope size as may be necessary, these being connected by mean of long internal sleeves C. The plunger sections are turne< true and highly polished, and the screw threads at th ends are made with great accuracy, so as to hold the sec tions in perfect alignment when connected. The thread are also made extra long, so that the joints may be a strong as the other parts of the pipe. For the purpose o making the pipe sections come together perfectly centra when joined, the center portion of the sleeve is turned true and the ends of the pipe are bored to fit this portion ; whei the parts are screwed up, the turned central portion o the sleeve slides into the bored-out ends of the pipes am brings them into line, so that there is no point arouni the joint where one part projects over the other. The top of the cylinder is finished off with a casting 1 screwed to the top of the upper section of the cylinde barrel E. On top of the cylinder cap F is mounted stuffing-box casting G, containing the usual packing spac T and fitted with a gland G'. The latter is constructei so as to form a space surrounding the plunger to hold oi which is fed in from the oil cup K. Above this oil reser voir is a recess in which babbitt metal wiping rings I ar placed for the purpose of scraping the oil off the plunge as it moves up, and retaining it in the space in gland G' In Fig. 418 it will be noticed that buffers F are provide! for the car to rest upon when at the lower floor. Simila Cylinder Construction 87 buffers are also provided for the counterbalance W to rest upon, this to prevent running the car up against the over- head beams. The construction of the car buffers is shown in Fig. 420, which is an external view of the upper end of the cylinder taken at right angles to Fig. 419. The buffer consists of a plunger P made of pipe,' provided with a FIG. 420 cast cap P' and a rubber cushion P". The plunger P slides within a cylinder C, also made of pipe. Within this cylinder there is a spring that is compressed by the plunger, the lower end of the latter being provided with a flat head to press against the top of the spring. The cylinder C is held in position by a side extension F, formed on the top cylinder casting F. The nuts F' F" are screwed on the 88 Steam Engineering cylinder C, the latter being threaded, and by this means the height of the buffer is adjusted. To furnish additional support, so that the buffer may not be pushed down, and the thread of the nut F' stripped if the car should come down unusually hard, a pipe extension E is provided, ex- tending down to the . floor, or some other firm support. These buffers are set so as to be struck and compressed every time the car comes down to the lower floor, acting to stop the motion gradually. If the car descends at the normal speed, the buffer is compressed slightly, just a trifle more than is necessary to hold the unbalanced por- tion of the weight of the car, but if the car speed in ap- proaching the floor is excessive, the buffers will be com- pressed farther, and the car will run a few inches below the floor. Boiler Power for Elevators. The following very able discussion of this subject is presented by Charles L. Hub- bard in Power: "The power necessary to operate an elevator depends upon its size, the method of construction and counterbal- ancing, the speed, and the efficiency. Placing these con- ditions in the form of an equation : H.P. eX 33,000 in which W ^weight of live load, w=unbalanced weight of car, S= speed in feet per minute, e=efficiency. The elevators in most general use for passenger service are of the hydraulic and electric types; for freight work, some steam and belted elevators are in commission, the Boiler Power for Elevators 89 latter being connected directly with the line shaft in shops and factories. The general method of computing the power is the same for both hydraulic and electric elevators, al- though they differ to some extent in detail, making it ad- visable to consider them separately. The live load for a passenger elevator is usually figured on a basis of from 60 to 80 pounds per square foot of floor space, and the weight of the elevator itself from 100 to 125 pounds per square foot, which also includes the safety device. These figures will be found ample for cars of or- dinary construction, but may be exceeded somewhat in the case of metal cars of especially massive design. Hydraulic Elevators. It is common practice with ele- vators of this type to counterbalance up to about three- fourths of the weight of the car. The speed varies from, say 200, to 600 feet per minute, 400 feet being about the average for office buildings of medium size. The efficiency is in the vicinity of 60 per cent. In computing the boiler power, it is usually assumed that probably all of the elevators will not be running at one time at their maximum capacity; it must be remem- bered also that power is required only on the upward trip, as the weight of the car causes it to descend under the control of a suitable braking device. When there is no definite information at hand, it is customary to compute the power necessary to operate all of the elevators at one time under full load,' and base the boiler power on two- thirds of this result. Example. An office building has four hydraulic eleva- tors, each having a floor space of 30 square feet. What boiler power should be provided, using the following aver- age data : Live load, 70 pounds per square foot of floor space; weight of elevator, 100 pounds per square foot of 90 Steam Engineering floor space; speed, 400 feet per minute; efficiency, 60 per cent; steam consumption of pumps, 65 pounds per hour per horse-power. From the foregoing, JF=30X70X 3=6300; W =30X 100X3X0.25=2250. Then for a continuous upward movement with a full load the required horse-power would be : (6300+2250) 400 172 horse-power. 0.60X33,000 but, of course, under actual conditions one-half of the lime is occupied by the downward trips, and the power required is therefore only one-half of this, or 80 horse- power. Making allowance for stops at the various floors r.nd for the time that part of the elevators are idle, it may be assumed that it will be sufficient to provide for 70 per cent of the full time, or 0.70X86=60 horse-power. The steam consumption under the conditions stated would be 60X65=3,900 pounds per hour. Assuming 30 pounds of steam per boiler horse-power, which may be taken with sufficient accuracy when the pres- sure and feed-water temperature are not given, the re- quired boiler horse-power will be 3,900-^30=130. The boiler horse-power required for running a pump is com- puted in a similar manner to that for an engine. The rating, or capacity of a pump, however, is usually expressed in gallons of water per minute raised to a given height, instead of horse-power, as in the case of an en- gine. The weight of water in pounds per minute multiplied by the height in feet to which it is raised, divided by 33,000. will give tV.e ireful, or delivered work of the pump Boiler Power for Elevators 91 in horse-power. The friction of the water flowing through the passages and valves is so great under ordinary working conditions that not much more than 50 per cent of the indicated horse-power of the steam cylinders is represented by the net useful work. This calls for a large amount of steam in proportion to the work done, as shown by the table herewith, which gives the average steam consumption of the ordinary duplex pump. TABLE SHOWING AVERAGE STEAM CONSUMPTION OF DUPLEX PUMPS. Pounds of Steam per hour Type of Pnmp per delivered horse-power Simple non-condensing 120 Compound non-condensing 65 Triple non-condensing 40 High-duty non-condensing , 30 The head against which a pump works is the vertical distance between the surface of the water in the suction reservoir and that in the discharge reservoir. If the pump is delivering against a pressure, as in feeding a boiler, the pressure may be reduced to "feet head," by dividing the pressure per square inch by 0.43. Electric Elevators. The type of electric elevators most- ly used is the drum. The speeds at which this type com- monly runs may be taken as 300 and 500 feet per minute, respectively, for single, and double-drum machines; for regular work, speeds above 400 feet are not usually found necessary for the average building. So far as the necessary power is concerned, the single drum and duplex machines may be considered together. The efficiency of the?e is ordinarily from 50 to 70 per 92 Steam Engineering cent, although theoretically the former is the more efficient type. In practice it is not customary to count on much more than 50 per cent, which gives results on the side of safety. The method of balancing the electric elevators of the drum- type differs from that applied to the hydraulic, in that the entire weight of the car plus from 40 to 50 per cent of the maximum live load is counterbalanced. From this it is evident that with no load the power required to pull the car down is that necessary to raise the excess counter-weight, which may be taken as equal to one-half the maximum live load, and to overcome the friction of the machine. When the car is half loaded it is bal- anced, and the power required is that to overcome friction only. At full load the conditions are the same as for an empty car, except the power is required during the up- ward trip instead of the downward. It is evident that. power may be required for both the upward and downward trips, depending upon the number of people in the car, but it will never be as great at any one time as in the case of the hydraulic elevator. Example. Taking the same conditions as in the pre- ceding example, what boiler power will be required to operate electric elevators of the drum type, having an efficiency of 50 per cent and a speed of 300 feet per minute ? In this case u, the unbalanced weight of the car, disap- pears, and the maximum live load is equal to only one- half the weight of the people in the car, the other half being counter-balanced, so that: JF==30X70X3X0.5=3150 pounds, from which 3150X300 _ H ' P ' 0.50X33,000 =57 ' Boiler Power for Elevators 93 If the full load was carried on both upward and down- ward trips, or sufficient of it on the downward trip to overbalance the counter-weight and the friction of the car, the conditions would be the same as in the case of the hydraulic elevator, that is, power would only be required on the upward trip. This condition, however, does not hold, especially in the case of office buildings, where during the morning hours the maximum loads are on the upward trips, with empty or nearly empty cars coming down. Under these con- ditions the power is practically the same on both trips, owing to the necessity of raising the counter-weight when the car is descending. This makes it necessary to treat the problem the same as though the machine were raising a continuous load. Assuming, as before, that a certain amount of time is required for passengers to enter and leave the car, and that all of the cars will not be running at one time, we may take 70 per cent of the above, or 57X0. 7 =-10, as the maximum horse-power to be delivered continuously by the motor. Assuming efficiencies of 80, 90 and 85 per cent for the motor, generator and engine, respectively, the required indicated horse-power of the engine will be 40 1=62 horse-power. 0.80X0.90X0.85 The boiler power will, of course, depend upon the water rate of the engine. Assuming that a simple non-condens- ing engine is employed, requiring 30 pounds of steam per indicated horse-power per hour, the boiler power will be practically the same as that of the engine, that is, 82 horse-power. The power required to operate duplex eleva- 94 Steam Engineering tors is practically the same, except a higher speed may be allowed." The method of balancing a screw machine is practically the same as for the hydraulic type. The efficiency of this machine may be taken as about 70 per cent. The horse- power for driving elevators of this type is calculated the same as for the hydraulic, except for the higher efficiency. After the power of the motor has been computed, the boiler power may be determined as in the preceding ex- ample. Freight elevators are computed in the same way, except they are run at lower speeds, and are built especially to carry the desired load in each particular case. When ap- plying these methods of computation to any particular case, the engineer should obtain all the data possible regarding the type of machine to be used, the probable speed, efficiency, etc., before proceeding; but if any of the data are lacking, the average figures already given may be used with approximate results. QUESTIONS AND ANSWERS. 661. What are the essential parts of the Otis traction elevator ? Am. A traction motor driving sheave, and a pair of electrically released brake shoes. 662. What type of electric motor is used in the Otis t '-action elevator? Ans. A slow speed shunt-wound motor. 663. What is the principal function of the armature shaft besides carrying the armature? Ans. To support the load, G64. How, then, is the drum, or sheave driven? Ans. By means of projecting arms from the armature, that engage with similar arms projecting from the drum. Questions and Answers 95 665. Describe the system of safety devices with which this elevator is equipped ? Ans. There are two groups of switches located respec- tively at top and bottom of the shaft, each switch in series being opened one after the other by the car as it passes. This retards the speed and finally brings the car to stop, applying the brake, independent of the operator in car. 666. Are there any other safeties besides this ? Ans. Yes speed governors, wedge clamps for gripping the guides, and potential switches. 667. Describe in general terms the construction of the Otis geared traction elevator ? Ans. A multi-grooved driving sheave around whicli the cable works. The sheave is mounted upon a shaft driven by geared wheels actuated by a right and loft hand worm cut on the armature shaft. 668. What advantage is gained by the use of the double screw, or worm ? Ans. The elimination of all end thrust. 669. With what kind of brake is this machine equipped? Ans. A mechanically applied, and electrically released brake. 670. What type of motor is used? Ans. Compound-wound speed 800 R. P. M. 671. When is the series field of this motor used? Ans. Only at starting. 672. Why? Ans. To obtain a highly saturated field in the shortest possible time. 673. How is a gradual slowing down of speed of car obtained with this elevator? Ans. By throwing a low resistance field across the ar- mature, thus providing a dynamic brake action. 96 Steam Engineering 674. "What kind of current is used for operating elec- tric elevators? Ans. Either alternating, or. direct current. 675. How is the transmission of current to the motor of an electric elevator controlled? Ans. By means of an electric magnet controller op- erated through the switch in the car. 676. How may considerable power be wasted in the operation of electric elevators? Ans. By careless handling making unnecessary stops and starts, or too sudden stops or starts. 677. Briefly, of what does the mechanism of a hydraulic elevator consist? Ans. A cylinder and piston with one or more rods con- nected to a crosshead which carries the sheaves over which run the lifting cables from which the car is suspended. 678. What moves the piston? Ans. "Water under pressure admitted by means of suit- able valves causes the piston to move from one end of the cylinder to the other, and back again. 679. How is this motion transmitted to the elevator car? Ans. By means of the sheaves mounted on the cross- head which carry the lifting cables. 680. In what position is the cylinder placed ? Ans. Either vertical alongside the hatchway, or hori- zontal in the basement of the building. 681. How are the valves of a hydraulic elevator op- erated ? Ans. In some cases by a hand rope passing through the car and over small sheaves at the top and bottom of the hatchway, and connected with the main valve in the basement. By pulling this rope down the valve is opened, Questions and Answers 97 and the car will ascend, while pulling the rope up will cause the car to descend. 682. What safety devices are attached to this type of elevator ? Ans. Two halls are attached to the hand rope, oue near the bottom, and the other near the top. These balls come in contact with the top, or bottom of the car, according as it is going up or coming down, and being carried along they, of course move the cable, thus actuating the valve, bringing the car to a stop. 683. Is this device safe, and automatic? Ans. It is. 684. Mention another safety device connected with hydraulic elevators. Ans. Safety clamps under the control of a speed limit centrifugal governor which causes the clamps to grip the guides and thus hold the car. 685. How is this safety governor operated ? Ans. By means of a small cable connected with the car and moving with it, which passes over the sheave pulley of the governor. 686. Why are some elevator pistons fitted with two pis- ton rods? Ans. To prevent the piston, and crosshead from turn- ing or twisting, and also to strengthen the construction. 687. What other methods are used for manipulating the water valve, besides the one already described? Ans. Running ropes, and standing ropes, either of which may be operated by means of a lever,, or wheel in the car. 688. Do these devices directly operate the main valve? Ans. No. They operate a small valve called the pilot valve. 689. What is the function of the pilot valve? 98 Steam Engineering Ans. When opened it admits the pressure water to a small cylinder with piston connected to the main valve stem. This actuates the main valve, which in turn, by its movement, closes the pilot valve. 690. Upon what does the amount of opening given the pilot valve, and consequently the main valve depend? Ans. Fpon the distance the lever in the car is moved from central position. 691. What is meant by central position of lever? Ans. That position in which there is no flow of water either into or out of the cylinder, and the car is moving only by its momentum. 692. What is the result of moving the lever too quickly to central position when the car is moving at a high rate of speed? Ans. The motion of the car will be arrested with a sudden jerk. 693. How many kinds of horizontal hydraulic elevators are in use? Ans. Two. One is the pushing, and the other the pulling type. 694. Describe the action of the pushing type? Ans. The car being at the bottom, the pressure water is admitted behind the piston which then moves, pushing the crosshead and cable sheave and lifting the car. 695. Describe the action of the pulling type? Ans. It is the opposite of that just described. 696. Is there much difference in the valve mechanism of the horizontal, and vertical types of hydraulic elevators ? Ans. Very little except a few minor details. 697. What is meant by a double-deck machine? Ans. Where the floor space is restricted two, and some- times three or four machines are mounted one above the . other. Question* and Answers 99 698. What water pressure is usually carried in operat- ing the types of hydraulic elevators that have hitherto been described? Ans. Pressures not exceeding 200 Ibs., the average being 150 Ibs. per square inch. 699. Are any higher pressures than this being used for operating hydraulic elevators? Ans. Yes. Pressures of 700 to 800 Ibs. and higher. 700. Why are such high pressures used? Ans. Owing to increased height of buildings, and the demand for high car speed. 701. What advantage, other than high speed, is gained by the use of high pressure elevators? Ans. A reduction in the size of the valve mechanism, piston areas and piping. 702. Mention another advantage in connection with the high pressure system? Ans. A reduction in the loss by friction of the water passing through the pipes, owing to reduced areas. 703. What is the percentage of loss due to this cause? Ans. In low pressure machines from 10 to 30 per cent, and in high pressure machines from 5 to 6 per cent. 704. Describe in general terms the construction of the cylinder and piston of a high pressure machine. Ans. The cylinder area is reduced to about one-eighth that of the low pressure type, and the piston is a solid plunger. 705. How is the pressure maintained? Ans. The pump forces water into the lower end of the accumulator, an air-tight tank, which is also weighted. From the accumulator a pipe runs to the main valve. 706. Describe in general terms the construction and operation of the direct-acting plunger elevator. 100 Steam Engineering Ans. A cylinder is set vertically in the ground under the center of the car, and the length of it is slightly greater than the travel of the car. In this cylinder is a plunger of the same length, which carries the car. Water under pressure is forced into the cylinder and thus lifts the car, and allowed to run out at the top when the car descends. The cylinder is about two inches larger in dia- meter than the plunger, and is always full of water. 707. What is the usual diameter of the plunger? Ans. G!/> to 7 inches. 708. How is it constructed? Ans. Of lengths of highl} r polished steel pipe, joined together with an internal sleeve, and having its lower end closed. 709. What pressure is ordinarily used on this type of elevator ? Ans. 150 to 200 Ibs. per square inch. 710. How is the top of the cylinder arranged ? Ans. With a packing gland through which the plunger moves up and down. 711. What types of elevators are in general ue for passenger service? Ans. Electric and hydraulic. 712. How is the capacity of a pump usually expressed? Ans. *In gallons of water per minute raised to a given height. 713. What is meant by the head under which a pump works ? Ans. The vertical distance between the surface of the water in the suction reservoir, and that in the discharge reservoir. INDEX A Accumulator , 70-72 Advantages of High Pressure Elevators 67-G8 Alternating Current Machines 19 Armature Shaft 11 B Boiler House Power for Elevators 88-94 Brake Shoes 18 C Car and Counterbalance 16 Careless Operation 21-2(3 Cost of 22 Dangers connected with 20 Circulating Pipe 46 Controlling Equipment 13-14 Counterbalancing 13 Cross Head 77 Cylinder and Plunger 75-79 D Direct Acting Plunger Elevator 79-88 Construction of cylinder , .84-87 Construction of plunger 81-82 Installation of 80-81 Principles of .79, 81-83 Double Decked Machines 61-63 Double Screw Machine 16-17 Driving Cables 12-13 E Electric Elevators . ,..11-22 ii Index F Freight Elevators 94 G Governor Types of 31-30 H Hand Rope Control 2S-29 High Pressure Elevators c7-7!> Action of water in 70-72 Accumulator 70-74 Advantages C7-CS Arrangements of parts t:S-70 Cylinder and plunger 7.V79 Pilot valve 72-7.". Horizontal Cylinder Type .".">-( '7 Details of operation nc-rvr General arrangement ">-~t"t Pulling type fi7 Pushing type 27-2S Horse Power required Electric Elevator 1)1-94 Rules for calculating 93 Hydraulic Elevators 2:5-S8 General principle of 20-28 L Lever Car Switch 21 Low Pressure Vertical Cylinder Type . .2s-."> Governor for 31-3'J Hand rope control 2S-29 Operating valve ; 23, 30-43 Safety devices for 31 Speed limit 29-30 M Main Valve 74-75 Method of Stopping IS Morse Williams & Co's Elevators 01-07 Double decked machines 01-03 Operation described 63-04 Index iii Stop and main valves 64-67 Motor for Electric Elevators 18 O Oil Cushion Buffers . ; 14-15 Operating Devices 47-55 Operating Valve 27, 36-43 Action of 38-40 Description of parts 36-38 For high speeds 36-43 Otis Geared Traction Elevator 15-21 Car and counterbalance 16 Double screw machine 16-17 Method of stopping 18 Motor 18 Traction principle 16 Otis Traction Elevator 11-15 Armature shaft 11 Controlling equipment 11 Counterbalancing 13 Driving cables 12-13 Slow speed motor 12 Safety devices 15 P Packing for Hydraulic Pistons 44 Pistons for Hydraulic Elevators 44-46 Piston Rods 46 Pilot Valve 72-73 Q Questions and Answers 94-100 R Rules for Calculating Horse Power 93 S Safeties 19-21 Safety Devices 15, 31 Shaft 18 Slow Speed Motor 12 iv Index, Speed Limit 29-3 Speed Regulator Action of 77-7 Steam Consumption Duplex Pumps 9 Stop and Main Valves G4-0 T Table of Currents and Fuse Capacity 2 Traction Principle 1 Twentieth Century Machine Shop Practice By L. ELLIOTT BROOKES The best and latest and most practical work published on mod- ern machine shop practice. This book is intended for the practical instruction of Machinists, Engin- eers and others who are interested in the use and operation of the machinery and machine tools in a modern machine shop. The first portion of the book is devoted to practical examples in Arithmetic, Decimal Fractions, Roots of Num- bers, Algebraic Signs and Symbols, Reciprocals and Logarithms of Numbers, Practical Geometry and and Mensuration. Also Applied Mechanics which includes: The lever, The wheel and pinion, The pulley, The inclined planes. The wedge The, screw and safety valve Specific gravity and the velocity of falling bodies Friction, Belt Pulleys and Gear wheels. Properties of steam. The Indi- cator, Horsepower and Electricity. Tb". latter part of the book gives full and complete information upon the fallowing subjects: Measuring devices. Machinists' tools. Shop tools. Machine tools. Boring machines, Boring mills, Drill presses, Gear Cutting machines. Grinding Machines, Lathes and Mill- ing machines. Also auxiliary mach ne tools, Portable tools, Miscella- neous tools. Plain and Spiral Index furnaces, Shop talks. Shop kinks, Medical Aid and over Fifty tabl The book is profusely illustra ng machines, Notes on Steel. Gas :ed and shows views of the latest sry and the most up-to-da driven machine tools, with full info tion. It has been the object of the author to presei matter in this work in as simple and not technical possible. e and improved belt and motor- mation as to their use and opera- the subject aimer as is 12mo, cloth, 636 pages, 456 fine illustrations, price, $2.00 Sold by Booksellers generally, or sent postpaid to any address upon receipt of Price by the Publishers FREDERICK J. DRAKE & CO. PUBLISHERS CHICAGO, U. S. A. THE KING OF ALL The Companion Volume to Modern Wiring Diagrams Just from the Press Electrical Wiring * Construction Tables By Henry C. Horstmann and Victor H. Tousley Contains hundreds of easy up-to-date tables covering everything on Electric Wiring. Bound in full Persian Morocco. Pocket size. Round corners, red edges. PRICE, MET, $1.50 Partial Table of Contents This Book contains among others: Tables for direct current calculations. Tables for alternating cur- rent calculations. These tables show at a glance the currents re- quired with any of the systems in general use, fcr any voltage, effici- ency, or power-factor, and by a very simple calculation (which can be mentally made), also the proper wire for any less. Tables showing the small- est wire permissable with any system or num- ber of H. P. or lights under "National Electri- cal Code" or Chicago rules. Very convenient for contractors. Tables for calculating the most economical loss. Tables and diagrams showing proper size of conduits to accommo- date all necessary combinations or number of wires. Tables and data for estimating at a glance the quantity of material re- quired in different lines of work. AS this is intended for a pocket-hand-book everything that would makes it unnecessarily cumbersome is omitted. There is no padding. Every page is valuable and a time saver. This book will be used every day be the wireman, the contractor, engineer and architect. AH parts are so simple that ver? "'ttle electrical knowl- edge is required to understand them. Sint, all chrages paid to any address, ttpon receipt of price. FREDERICK J. DRAKE & CO., Publishers, Chicago The Practical Gas Oil Engine HAND-BOOK A MANUAL of useful in- *"* formation on the care, maintenance and repair of f^is and Oil Engines. This work gives full and clear instructions on all points relating to the care, mainte- nance and repair of Stationary. Portable and Marine, Gas and Oil Engines, including How to Start. How to Stop, How to Ad- just, How to Repair, How to Test. Pocket size, 4x6V4. Over 200 pages. With numerous rules and formulas and dia- grams, and over 50 illustrations by L. ELLIOTT BROOKES, au- thor "f the "Construction of a Gasoline Motor," and the "Au- tomobile Hand-Book." This book has been written with the intention of furnishing practical information regarding gas, gasoline and kerosene engines, for the use of owners, operators and others who may be interested in their construction, operation and maa- agement. In treating the various subjects.it has been the endeavor to avoid all technical matter as far as possible, and to present the information given in a clear and practical manner. |6mo. Popular Edition Cloth. Price $1.00 Edition de Luxe-Full Leather Limp. Price 1.56 Sent Postpaid to any Address in the World upon Receipt of Price FREDERICK J. DRAKE & CO. PUBLISHERS CHICAGO, ILLINOIS. Easy Electrical Experiments and How to Make Them By L. P. DICKINSON This is the very latest and mosfj valuable work on Electricity for the amateur or practical Electrician pub- lished. It gives in a simple and easily understood language every thing you should know about Gal- vanometers, Batteries, Magnets, In- duction, Coils, Motors, Voltmeters, Dynamos, Storage Batteries, Simple and Practical Telephones, Telegraph Instruments, Rheostat, Condensers, Electrophorous, Resistance, Electro Plating, Electric Toy Making, etc. The book is an elementary hand book of lessons, experiments and inventions. It is a hand book for beginners, though it includes, as well, examples for the advanced students. The author stands second to none in the scientific world, and this exhaustive work will be found an invaluable assistant to either the Student or mechanic. Illustrated with hundreds of fine drawings; printed on a superior quality of paper. J2mo Cloth. Price, $J.25, Sent postpaid to any address upon receipt of prio ^REDERICK J. DRAKE & CO.. Publishers^ CHICAGO, ILL. DYNAMO TENDING ENGINEERS Or, ELECTRICITY FOR STEAM ENGINEERS Sy HE3STRY C. KOESTMANN and VICTOR H. TOUSLEY, Authors of "Modern Wiring Diagrams and Descriptions for Electrical Workers." This excellent treatise is written by engineers for engineers, and is a clear and comprehensive treatise on the prin- ciples, construction and operation of Dynamos, Motors, Lamps, Storage Bat- teries, Indicators and Measuring Instru- ments, as well as full explanations of the principles governing the generation of alternating currents and a descrip- tion of alternating current instruments and machinery. There are perhaps but few engineers who have not in the course of their labors come In contact with the electrical apparatus sucli as pertains to light and power distribution and generation. it the present rate of increase In the use of Electricity it is but a question of time when every steam Installation will have in connecton with it an electrical generator, even In such buildings where light and power are supplied by some central station. It is essential that the man in charge of Engines, Boilers, Elevators, etc., be familiar with electrical matters, and it cannot well be other than an advantage to him and his employers. It is with a view to assisting engineers and others to obtain such knowledge as will enable them to intelligently manage such electrical apparatus as will ordinarily come under their control that this book has been written. The authors have had the co-operation of the best authorities, each in his chosen field, and the information given is just such as a steam engineer should know, To further this information, and to more carefully explain the text, nearly 100 illustrations are used, which, with perhaps a very few excep- tions, have been especially made for this book. There are many tables covering all sorts of electrical matters, so that immediate reference can be made without resorting to figuring. It covers the subject thoroughly, but so simply that any one can understand it fully. Any one making a prtense to electrical engineering needs this book. Nothing keeps a man down like the lack of training; nothing lifts him up as quickly or as surely as a thorough, practical knowledge of the work he has to do. This book was written for the man without an opportunity. No matter what he is, or what work he has to do, it gives mm just such information and training as are required to attain success. It teaches just what the steam engineer should know in his engine room about electricity. 13mo, Cloth, 100 Illustrations. 8ize5^x7^. PRICE NET *l ffk Sold by booksellers generally, or sent, all charges paid, upon Ql i vU receipt of price ' FREDERICK J. DRAKE & CO., Publishers CHICAGO, ILL. COMPLETE EXAMINATION QUESTIONS AND ANSWERS FOR MARINE AND STATIONARY ENGINEERS > By Calvin F. Swingle, M. E. Author of Swingle's Twentieth Century Hand Book for Steam Engineers and Electricians. Modern Locomotive Engineering Handy Book, and Steam Boilers Their construction, care and management TjTHIS book is a compendium of ^ useful knowledge, and prac- tical pointers, for all engineers, whether in the marine, or station- ary service. For busy men and tor those who are not inclined to snend any more time at study than is ab- solutely necessary, the book will prove a rich mine from which they may draw nuggets of just the kind of information that they are look- ing for. The meihod pursued by the au- thor in the compilation of the work and in the arrangement of the sub- ject matter, is such that a man in formation relative to the operation of his steam or electric plant, will experience no trouble in finding that particular item, and he will not be under the necessity of going over a couple of hundred pages, either, before he finds it because the matter i s systematically ar- ranged and classified. The book will be a valuable addition to any engineer's library, not alone as a convenient reference book, but also as a book for study. It pages fully illustrated, durably bound in full Persian Morocco limp, round corners, red edges. PRICE $1.50 N. B. This is the very latest and best book on the subject in prim. (Sold by Booksellers generally or sent postpaid to any address upon receipt of price by the Publishers FREDERICK J. DRAKE & CO. CHICAGO. U. S. A. MODERN ELECTRICAL CONSTRUCTION By HORSTMANN and TOUSLEY 7TTHIS book treats almost entirely of practical electrical ^ work. It uses the ' 'Rules and Requirements of the Na- tional Board of Fire Underwriters" as a text, and ex- plains by numerous cuts and detailed explanations just how the best class of electrical work is installed. It is a perfect guide for the beginning electrician and gives him all the theory needed in practical work in addition to full practical instructions. For the journeyman electrician it is no less valuable, be- cause it elaborates and explains safety rules in vogue throughout the United States. It is also ^E^tvAjrMyjkTw^^^^yo.jL^Tj'wiTyj of especial value to elec- uic-l inspectors, as it g ^JaSd 7 !^ u h n e scrupulous persons in the trade. The book also contains a number of tables giving di- mensions and trade num- bers of screws, nails, in- sulators and other material in general use, which will be found of great value in practice. There is also given a method by which the diameter of con- duit necessary for any number of wires of any size can be at once determined. The motto of the authors, "To omit noth- ing that is needed and include nothing that is not needed, " that has made "Wiring diagrams and Descriptions" so suc- cessful, has been followed in this work. No book of greater value to the man who does the work has ever been published. 16mo, 250 pages, 100 diagrams. Full leather, limp. i- Price, net, ft. SO Sent postpaid to any address in the world upon receipt of priss FREDERICK J. DRAKE & CO. PUBLISHERS CHICAGO, ILLINOIS. The Calculation of Horse Power Made Easy : : : By L. ELLIOTT BROOKES Author of "Gas and Oil Engine Hand-Book," "The Automobile Hand-Book," Etc. Size, 5x7%. 80 Pages, Illustrated. Cloth, 75 Cents THIS work deals in a practical and non- technical manner with the calculation of the power of Steam Engines, *Explo- sive and Electric Motors. Particular attention has been given to the full explanation of the elementary principles upon which the calculations are based. It has been the endeavor to present in as simple a manner as is possible, a number of useful rules and formulas that may be of great value to ENGINEERS, MACHINISTS and DESIGNERS in calculating horse power. Rules for plotting steam engine diagrams by arithmetical, geometrical and graphical methods are given and fully explained, also the method used in plotting the diagram of an explosive motor. This work covers many points regarding the calculation of horse power and useful information not hitherto published in a single volume, and includes Calculated, Brake and Indicated horse power, Point of cut-off and average steam pressure, Horse Power of Explosive Motors, Degree of Compression and Combustion Chamber Dimensions, Indicator Diagrams of Steam Engines and Explosive Motors, also tables of Average Steam Pressure, Areas of Circles, Squares of Diameters of Circles, Natural Logarithms of Num- bers, Thermo-dynamic Properties of Gasoline and Air, Common Logarithms of Numbers, and Mensuration of Surface and Volume. The term " Explosive Motor" includes Gas, Gasoline and Oil Engines. SENT POSTPAID TO ANY ADDRESS IN THE WORLD UPON RECEIPT OF PRICE FREDERICK J. DRAKE & CO. PUBLISHERS PUBLISHERS. CHICAGO, ILL. Practical Mechanical Drawing and Machine Design Self-Taught By CHARLES WESTINGHOUSE Over 200 Illustrations and 160 Pages. Price, $2 00 A COMPLETE SELF -INSTRUCTOR FOR HOME STUDY on Drafting tools Geometrical defini- tion of plane figures Properties of the circle Poly- gons Geometrical definitions of solids Geometrical drawing Geometrical problems Mensuration of plane surfaces Mensuration of volume and surface of solids The development of curves The development of sur- faces The intersection of surfaces Machine drawing Technical definitions Material used in machine con- struction Shafting Machine design Transmission of motion by belts Horsepower transmitted by ropes Horsepower of gears Transmission of motion by gears Diametral pitch system of gears Worm gearing Steam boilers Steam engines Tables. Frederick J. Drake & Co., Publishers CHICAGO, U. S. A. Practical Armature and Magnet Winding By HENRY C. HOUSTMANN and VICTOR H. TOUSLEY w P HILE the subject of armature wind- ing has, in the past, been more or less completely covered, most of these works have been either too technical in their composition or have required a fair degree of knowledge of the subject before they could be clearly understood. There has been a need of a book cover- ing this matter which, while giving all that is necessary for an intelligent under- standing, would, at the same time, present the matter in such a simple form that it could be readily grasped by those who had not had the benefit of a previous education along this line. This book treats in a practical and con- cise manner this very important subject. All practical armature windings are fully explained with special atten- tion paid to details. All questions which are apt to arise in the minds of the students have been completely answered. Numerous illustrations have been supplied, and these, taken in con- junction with the text, afford a ready means for either the study of the armature or f6r a book of reference. It has been the aim of the authors to supply all the necessary informa- tion required by the subject and, at the same time, to give this informa- tion in as condensed and brief a form as is consistent with a clear understanding. Various useful tables have been especially prepared for this work and these will not only reduce to a minimum the number of calculations re- quired, but lessen the possibility of errors. A chapter on the calculation of armatures gives complete information in detail for the design of an armature. Sold by booksellers generally or sent postpaid to any address upon receipt of price. 16mo., Pocket Size, Full Persian Morocco Leather, Round Corners, Red Edges - $1.50 FREDERICK J. DRAKE & CO. PUBLISHERS .... CHICAGO, ILLINOIS OPERATORS' WIRELESS TELEGRAPH AND TELEPHONE HAND-BOOK By VICTOR H. LAUGHTER TP-TO-DATE and most com- plete treatise on the subject yet published. Gives the historical work of early investi- gators on up to the present day. Describes in detail the construc- tion of an experimental wireless set. How to wind spark coil and dimensions of all size coils. The tuning of a wireless station is fully explained with points on the construction of the various instruments. A special chapter on the study of wireless telegraphy is given and the rules of the Naval sta- tions with all codes, abbrevia- tions, etc., and other matter in- teresting to one who takes up this study. The most difficult points have been explained in non- technical language and can be understood by the layman. Wireless telephony is given several chapters and all the systems in use are shown with photographs and drawings. By some practical work and a close study of this treatise one can soon master all the details of wireless telegraphy. Sold by booksellers generally or sent postpaid to any address upon receipt of price. 12mo., Cloth, 210 Pages, Fully Illustrated, and with Six additional Full-Page Halftone Illustrations Showing the In- stallation of "Wireless" on the U. S. War Ships and Ocean Liners $1.00 FREDERICK J. DRAKE & CO. PUBLISHERS CHICAGO, ILLINOIS ELEMENTARY ELECTRICITY UP TO DATE By SIDNEY AYLMER-SMALL, M. A. I. E. E. THIS book opens up the way for anyone who desires an accurate and complete knowledge of elec- tricity as a useful agent, in the hands of man, for the transmission of me- chanical energy, and the creation of light. In addition to opening up the way as referred to above, the book also serves as a guide and instructor to the seeker after knowledge along these lines. Beginning in the form of a simple catechism on the primary aspects of the subject it conducts the student by easy stages through the various as- pects of static electricity, the different types of apparatus for producing it, all of which are plainly described and illustrated and their action made plain and easy of comprehension. Quite a large space is devoted to this important topic, although no more than is actually necessary, as the subjects of condensers and simple electrical machines are also thoroughly handled, and the principles governing their action clearly explained and illustrated. The subject of atmospheric electricity is next dealt with, and lightning arresters treated upon, especially in their relation to electric power stations, sub-stations and line wires. The wonderful and mysterious subject of magnetism is next treated upon at length and clearly explained the explanations being accompanied by illustrations. Primary batteries of all types, storage batteries and the effects of elec- trolysis each and all receive a large share of attention. Electric circuits and the laws governing the flow of current, including Ohm's law, are all clearly explained. The student has now arrived at the point where electrical work, power and efficiency is the topic, and where the genera- tion and transmission of electrical currents of high potential and large volume are explained. Sold by booksellers generally or sent postpaid to any address upon receipt of price. 12mo. Cloth, 500 Pages, Fully Illustrated : Price, $1.00 FREDERICK J. DRAKE & CO. PUBLISHERS CHICAGO, ILLINOIS University of California SOUTHERN REGIONAL I . LIBRARY FACILITY 405 Hilgard Avenue, Los Angeles, CA 90024-1388 Return this material to the library from which it was borrowed. 2 WEEK OC1 _ -URL OV 10 31991 A 000 351 062 5