ELEMENTS OF WATER GAS A Practical Treatise on the jVLanufacture of vvater Gas By J. STEPHENSON 11 Member of American Chemical Society, Pacific Coast Gas Association Associate Member American Institute of Electrical Engineers FIRST EDITION 1916 THE STATE COMPANY, COLUMBIA, S. C. COPYRIGHTED, 1916 By J. STEPHENSON PREFACE The object of this work is to briefly outline the development of water gas to its present stage, and enable the reader to grasp the fundamental principles which govern the past and future developments. It will be observed that only such apparatus has been referred to that con- stitute an important and established develop- ment of the process, and the author realizes that the subject is far from being exhausted. The work, however, is intended to provide a stepping stone to a later study, and technicalities have been avoided as far as possible. To the reader interested in water gas manu- facture, it is hoped that a perusal of this work will educate him in a general way into the prin- ciples of the process. To the student who contemplates gas engi- neering as a profession, it need hardly be said is especially adapted. To the salesman it will give a brief outline into the principles of modern developments, and enable immediate comparison with his own par- ticular plant. 349 6 Contents CHAPTEK IV. The Vertical Type. Williamson's Generator Water Seal Valve. CHAPTER V. Twin Generator Systems. Convertible Apparatus Continuous Process. CHAPTER VI. Automatic Control. General Remarks Blast Pressures Temperature Conditions Advantages Conclusive Remarks. CHAPTER VII. Mechanical Operation. Cam and Clutch Mechanism Rotary Valves. CHAPTER VIII. Electrically Controlled Process. Carburetted Water Gas Blue Water Gas. CHAPTER IX. Hydraulic and Air Systems. Hydraulic Control Air Control. Contents 7 CHAPTER X. Construction Developments. Valve Mechanism Automatic Clinkering Car- buretting Zone Self-sealing Cap Notes on Construction Excavation Concrete B r i c k- work Columns and Girders Carpentry. APPENDIX. Tables and Factors. ELEMENTS OF WATER GAS CHAPTER I. EARLY HISTORY. The origin of water gas goes back to the year 1780, when Fontana, a French chemist, discov- ered that by passing steam through incandescent fuel containing carbon, the oxygen of the steam had greater affinity for the carbon than its com- bining element hydrogen, and thereby the steam was broken up as follows: C+H2O=H2-|-CO. It was not, however, until some 50 years later that this reaction was used commercially, when Michael Donavan distributed it for public light- ing in Dublin, Ireland. Briefly, this attempt consisted of passing steam through coke heated to redness in contact with vapors of spirits of turpentine, tar, coal naphthalene, or other illum- inating agents, but did not, however, meet with much success, and little appears to have been done in further developments until the year 1858, when Dr. J. M. Sanders erected a plant in Philadelphia, to supply gas to a certain Girard House. In this design of plant a series of (L) shaped retorts 1 (Fig. 1) were set in an ordinary coal gas setting, and filled with charcoal, and heated 10 Elements oj TF 'cuter Gas Elements of Water Gas 11 externally by furnace 2 while steam and melted rosin were passed downwards by way of pipe 3 through the bed of fuel, the resultant products passing up through the standpipe to an hy- draulic main. This process was proven to be about 10 per cent, more expensive than coal gas, and in due course was abandoned. The next attempt worthy of note was in 1873 by the Allen-Harris system, which consisted of passing superheated steam through anthracite coal in an ordinary coal gas bench, and then passing the water gas into retorts distilling coal gas from bituminous coal. In this process it was claimed that the distillation of coal in an atmos- phere of water gas protected some hydrocarbons from decomposition that otherwise broke down into tar, and thereby increased the quantity of gas to about 30 per cent, without any appreci- able loss in candle power, and a confirmation of this claim appears to be seen in the fact that the yield of tar was approximately two gallons less per ton of coal than in ordinary coal gas practice. The theoretical principle involved in this process has been the subject of much discus- sion of recent years, but as yet no design of plant has met with any remarkable success and the advantage claimed can not be accurately con- firmed. 12 Elements of Water Gas The developments following the Allen-Harris system were chiefly for the utilization of naph- thas, obtained as a by-product in the petroleum industry, and one of the most interesting con- sisted of a bench of vertical retorts charged with anthracite coal, through which superheated steam was passed, and a series of horizontal retorts which were divided by a partition which extended nearly to the back of the retort. In the latter retorts oil was sprayed by means of steam, and the water gas from the vertical retorts mixed with it, after which the mixture traversed the bottom section from front to back, and the top section from back to front, and then up the standpipe to an hydraulic main. The retort processes were continued for some time in a variety of ways, and the last known appears to have been the Slade or Salisbury process, which was finally abandoned in favor of the generator-retort system. In the development of the generator-retort system the most successful attempts were those of Tessie Du Motay and Wilkinson. In the former apparatus, blue gas was made intermit- tently in a double generator, and stored in an hydrogen holder, from which it was drawn and passed through a steam heated evaporator, where it took up naphtha vapors. The mixture of Elements of Water Gas 13 gases were then sent through externally heated retorts, the function of which was to fix into permanent gases. The Wilkinson apparatus, whilst different in construction, was practically the same in prin- ciple as the former, and one particularly inter- esting feature in it is that it was the first appa- ratus on which the down or reverse run is known to have been used on the generator. Various modifications of these principles fol- lowed, of which the Hanlon-Johnson, Edgerton, Mackensie, and Egner types were the most important. In the first named, water and oil gas were made and stored in separate holders and mixed cold, whilst in the Edgerton, the oil gas was pro- duced in vertical retorts heated by the producer gases froijn the generators, and the gases sep- arately sirred and mixed cold. The Mjfekensie apparatus attempted at a con- tinuous production by carburetting producer gases with oil in coal gas retorts, and in the Egner process blue water gas was made in gen- erators heated by air drawn through the fuel l>ed, and the water gas carburetted with oil in coal gas retorts. These attempts were proved unsuccessful, and in due course the generator- retort system was finally abandoned with the 14 Elements of Water Gas advent of the internal combustion system, which laid the foundation of modern water gas prac- tice. The original apparatus for the generation ol enriched water gas by the internal combustion system was invented during the Civil War, in Elements of Water Gas 15 1874, by Dr. C. S. Lowe, who was then engaged in the manufacture of balloons. The apparatus, which is shown in Fig. 2, comprised a generator 1, and a fixing chamber 2, and was heated by forced blast with secondary combustion in the fixing chamber. In the run of gas, oil was sprayed into the top of the generator, passed through the fixing chamber to a washer, and through a boiler for the production of steam used in the generator. The inventor, in his patent application, laid special importance on the advantages of vaporizing oil in the presence of hydrogen, and also claimed a reduction of fuel consumption by the utilization of wasted gases from the generator by the internal heating of the fixing chamber. This system was afterwards modified in various ways, the most important of which was that of Granger and Collins, in which the gen- erator was placed so that the top was level with the bottom of the fixing chamber, or superheater, and only a short, straight connection was required. This design met with marked success for several years, and the advantages claimed were : (1) Convenient means of operation. (2) Reduction of ground area. (3) Free access to fire for cleaning. 16 Elements of Water Gas (4) Minimum amount of heat lost by short connection between generator and super- heater. Another modification was the Hanlon-Leadley, which consisted of three generators connected to two steam and two gas superheaters. The gen- erators were blasted in parallel and steam in series, the object of which was to provide a low fuel bed in blasting and thereby minimize the percentage of carbon monoxide, and a deep bed in steaming to minimize the percentage of car- bon dioxide in the water gas. The steam used in the generators was first passed through the steam superheaters, and the oil gas and water gas were permanently fixed by passing through the gas superheaters in parallel. It may be interesting to note that this apparatus appears to have been the origin of modern twin-generator practice discussed later in this work. In the years following these developments it became necessary to use a heavier grade of oil, and the first important development was made by the Lowe apparatus which consisted of add- ing another superheater and increasing the. height of the second superheater to increase the fixing surface of the gases and also provide a draft from the generator when the charging door was opened. The height of the entire Elements of Water Gas 17 machine was also increased to provide a deeper fuel bed, and, in about 1890, means were pro- vided to run the steam in an upward and down- ward direction, after which the developments consisted of minor and mechanical details. With the progress of the internal combustion system it was found, however, that only hard coal or coke could be used with advantage, and many attempts have been made to use the cheaper soft or bituminous coals, but up to the present date this practice has not met with any remarkable success, although some interesting plants have been designed for the purpose. One of the most noteworthy attempts to- use soft coal was made by the Rose-Hasting appa- ratus, which is illustrated in Fig. 3. In this design the generator 1 is charged with soft coal about every 50 minutes, and carries a bed of fuel approximately 8 feet deep, and the regen- erator 2 is charged with coke or hard coal. The operation of this plant consists of first blasting 1 and 2 with stack valve 1' open for a period of 5 minutes, after which the stack valve 2' was opened and 1' closed for about 2 minutes, and then the stack valve 3' opened and 2' closed, dur- ing which time secondary air was admitted to the base of 3 as required until the end of the blast- ing period. During the run of gas steam was 18 Elements of Water Gas admitted below the grate in generator 1, and the gas passed through the checkerbrick in 1 to the top of the checkers in 2, where it mixed with oil sprayed into the top of the chamber by steam. The gas then passed through the bed of fuel in 2 and up superheater 3. The object of the regen- erator in this apparatus was to improve the quality of the water gas made in the generator by converting the high percentage of carbon Elements of Water Gas 19 dioxide in carbon monoxide, and also to assist in fixing the oil vapors. Another method tried for some time was the Fehiiehjelm apparatus, which consisted of a gen- erator extending into the superheater to form a vertical retort, the purpose of which was to coke the coal before being discharged into the generator. In view of the fact that a modern water gas machine will consume approximately 2,000 pounds of fuel per square foot of grate area in 24 hours, it is evident that the primary object to this plant was that the capacity of the vertical retort was inadequate in producing suf- ficient fuel for the generator. The Rew apparatus was another modification of plant designed for the use of soft coal, and was built and operated in pairs. In this plant, Fig. 4, the air blast was admitted beneath the grate in both generators 1 simultaneously, and passed over a bed of fuel in chamber 2, and down regenerator 3. Primary air was also admitted beneath the grate in coking chamber 2 at 4, and secondary air to the top of generator at 5 and regenerator at 6. During the run of gas steam was admitted to the base of one regenerator at 7, and traveled up and down over the bed of soft coal in 2, by which it picked up hydrocarbons, and then passed down through the fire of one 20 Elements of Water Gas generator and up through the fire of the other and over the second bed of coal. The gases then passed to the second regenerator, where they were met by a spray of oil, after which they O'L. traveled to the base of the lower regenerator and led off to the washing plant. At the end of the run the air blasting was repeated and the direction of flow in the following run reversed. This apparatus can not be claimed to have been Elements of Water Gas 21 a permanent success, and its disadvantages appear to have been in the caking and sticking of coke in the coking chamber, and the compara- tively large amount of labor necessary for the operation of the plant. Various modifications embodying these prin- ciples followed, but have either been abandoned or altered for the manufacture of producer gases for power purposes, and in view of the fact that this work is intended to discuss water gas appa- ratus exclusively, the modifications referred to will not be further dealt with. CHAPTER II. ELEMENTS OF INTERNAL COMBUSTION PROCESS. The internal combustion process was, as pre- viously stated, originally invented by Dr. S. C. Lowe in 1874, since when many designs of plants have been brought forward, each embodying some new advantage or claim. In general, how- ever, the modern carburet ted water gas appa- ratus consists of a generator for producing water gas according to the reaction C+H2O= H2+CO, a carburettor for gasifying oil, a super- heater to permanently fix the gases produced in the said chambers, an hydraulic seal to remove a certain amount of tarrv matter and seal the 22 Elements of Water Gas gases when the machine is opened, and a scrub- bing and condensing plant. THE GENERATOR. The function of the generator is to produce water gas according to the previous reaction, and also to produce carbon monoxide to be burnt in the carburettor and superheater in order to supply the necessary heat for the gasification of the oil. This unit consists of a heavy steel shell 1, Fig. 5, which contains a firebrick lining 2, a set of grate bars 3, air and steam blast inlets 4 and 5, a gas outlet 6, clinker and ash doors 7, and a charging door 8, with sight cock 9. In the operation of this chamber for the gen- eration of water gas, a blast of live steam is passed through a bed of highly incandescent fuel, containing carbon, which by reason of its greater affinity combines with the oxygen of the steam and liberates free hydrogen, thereby forming the two combustible gases, carbon monoxide and hydrogen. In this part of the reaction heat is absorbed from the fuel and after a certain time the fire has to be revived. This is accomplished by cutting off the steam and admitting a blast of air beneath the grate bars, which combines with the carbon in the lower part of the gene- Elements of Water Gas 23 24 Elements of Water Gas rator, as follows: C+O2=CO2, and the carbon dioxide formed is converted to carbon monoxide is passing up through the fuel as follows: CO2+C=2CO. This gas is led from the gen- erator to the carburetter and superheater, where it is met by another blast of air and burnt as CO2 for the subsequent heating of these cham- bers. After the heating period continues for a sufficient length of time, the air blasts are cut off and the gas-making period again commenced by passing steam through the fuel. In Fig. 5 it is seen that steam inlets are pro- vided at both the top and bottom of the gen- erator as the continual passage of steam in an upward direction would deaden the lire at the bottom, and it is necessary to pass it in a down- ward direction about once in three periods. The percentage of fluids used vary with the nature of the fuel and working temperatures of the plant, and an excess amount of steam will lower the temperature of the fuel too much and pro- duce carbon dioxide, which is very detrimental to the calorific and illuminating power of the gas. It is seen, then, that the keeping of the fuel bed at a uniform temperature is a very important factor in keeping down the percentage of CO2, and the sight cock provided, when used frequently, is of valuable service, as the operator Elements of Water Gas 25 soon becomes expert in judging the correct tem- perature. CARE OF THE FIRE. One of the most important factors is gas mak- ing is the controlling of the generator tire, and whilst engineers differ in their opinion as to the correct number of runs to be made in each charge, an average of the methods adopted may be taken at six runs when coal is used, and four when coke is used. This should be done after the run of gas, and the operator should always take care to blow the gas from the machine by opening the blast valve for a few seconds before opening the charging door, or an explosion will result when the combustible gases .meet the oxygen in the atmosphere. After six or eight hours' continuous operation, it is found that a^h and metallic residue from the fuel accumulates in the lower part of the machine, and prevents the air and steam from passing freely through the fire, and thereby seriously interferes with the capacity of the apparatus. It is then neces- sary to temporarily shut down the plant ana remove the clinkers by means of the doors 7, Fig. 5, and in preparation of this the fuel bed is burned well down to allow the removal of clinkers which may adhere to the generator wall. 26 Elements of Water Gas When the fire is at a suitable depth, the gas is first blown from the machine by the air blast, and then the charging door is opened and the gas lit off before opening the clinkering door. After the clinkers are drawn by means off bars and hooks, the ash pit door is opened for the withdrawal of matter which falls through the grate bars, and on reclosing care should be taken to clean the doors well to ensure a gas tight joint. If the machine is then to be shut down for the night it is charged well up, the depth of fuel made even all round, and the ash pit door slightly cracked to admit a small portion of air to keep the fire alive. If the machine, however, is to be put directly back to gasmaking, the doors are made tight and the air blast put on slightly longer than usual to heat the heavy charge of fresh fuel. CARBURETTER AND SUPERHEATER. The carburetter B, Fig. 6, comprises the second unit in a carburetted water gas set, and consists of a chamber with a steel shell lined with fire- brick, and is filled with a checkerwork of fire- brick, the purpose of which is to store up heat for the gasification of oil. It is provided with an oil inlet 1, an air blast inlet 2, a steam inlet Elements of Water Gas 27 28 Elements of Water Gas in the oil line 3, valve connections to the gen- erator A, and a passage to the superheater. During the heating or blasting period, the gases coming from the generator consist of carbon dioxide and carbon monoxide, and the sensible heat supplies a comparatively large proportion of the heat necessary to maintain the tempera- ture of the checkerwork. It is found, however, necessary to admit a portion of secondary air at 2 to burn the remainder of the gases and keep up the required temperature, which varies with the grade of oil used, but in a general way may be taken at from 1,400 to 1,600 degrees Fahren- heit. When the necessary heats have been reached, the air blasts are cut off, and oil is sprayed into the carburetter whilst steam Is being passed through the fuel in the generator, which results in breaking up the oil into Its component parts, and loading the otherwise non- luminous water gas with hydrocarbons of a high illuminating quality. The superheater C is the third unit in the process, of like construction to the carburetter, and is provided with a sight cock and air blast inlet at its lower portion, and a gas outlet and stack valve at the top of the chamber. This unit, which is sometimes known as the fixing chamber, is intended to fix the products of the previous Elements of Water Gas 29 chamber into permanent gases and complete the work of the generating plant. The air blast inlet, whilst provided in practically all types ot apparatus, is scarcely used inasmuch that the sensible heat from the carburetter is usually suf- ficient to maintain the temperature of this cham- ber, and it is only necessary to use the valve when starting a set after being shut down for repairs. On leaving the fixing chamber, tne blast gases enter into the atmosphere through the stack or through a waste heat boiler for the generation of steam, and the carburetted water gas during the run passes through the off-take to the wash box, which prevents the gas from returning when the stack valve is reopened, and then to the scrubbing and condensing plant. OIL SPRAY. In injecting the oil into the carburetter it is of great importance that it is distributed over the surface of the checkerbrick as evenly as pos- sible, as a straight injection is the cause of dead holes down the center of the carburetter where the oil enters, and a variety of devices have been used to distribute the oil evenly. One form of injector which the writer has found to give good results is shown in Fig. 7, and consists of a spray 30 Elements of Water Gas OtL. Elements of Water Gas 31 nozzle 1, which threads on a wrought iron pipe 2, and contains a disc 3, through which the valve rod 4 passes. The disc contains a series of small holes 5, and the spray nozzle and valve rod form a tapered joint 6, which produces a very tine injection. A protecting shield which threads in the head of the carburetter is also provided, and the spray can be readily moved for inspection by means of the nuts. These sprays are made in various sizes to atomize a certain number of gal- lons per minute, and the specified number can be adjusted by means of the hand wheel. PYROMETERS. The most commonly used pyrometers in the manufacture of water gas is the thermo-electric type, which depend for their action on the fact than when two metals in contact are heated and the cool end connected by a wire an electric cur- rent is generated in proportion to the tempera- ture of the heated contact. The metals employed usually consist of platinum and platinum-ro- dium, which are fused together at one end and connected at the other end to suitable indicating and recording gauges. These pyrometers are usually placed in the bottom of the carburetter and top of superheater, and are protected by a 32 Elements of Water Gas shield of wrought iron. The indicating gauge is placed on the operating floor to guide the gas- maker in his work, and the recording gauge is /o placed in the engineer's or superintendent's office to enable the temperatures of the machine to be ascertained at any time without leaving the office. As previously shown, the heats of the machine alternate with the blasting and gas- Elements of Water Gas 33 making period, and a recording chart of an effi- cient gasmaker would appear as illustrated in Fig. 8, in which the high heat represents the beginning of the run, and the low heat the begin- ning of the blow. WASHING, SCRUBBING, AND CONDENSING PLANT. After the carburetted water gas leaves the superheater it passes through the off-take pipe to the wash-box or seal, where a considerable amount of tar is deposited. This vessel usually consists of a cylindrical tank into which a stream of water is constantly passed to maintain a constant level in the box, and thereby prevent the gases from returning when the stack valve is opened. The mixture of tar and water is led from the wash-box at the overflow into a seal pot, from which it flows to a well or tar sepa- rator, and the gases pass up a hot scrubber and through a condenser to a relief holder. In Fig. 9 is shown one type of scrubber which is fre- quently used, and consists of a cylindrical tower filled with coke or layers of wooden trays, which break up the gas into fine streams as it passes upwards, and brings it in contact with hot water constantly passing down, which has the effect of removing more tar and suspended oils. These 34 Elements of Water Gas Elements of Water Gas 35 apparatus are provided with separate compart- ments, each of which are provided with large manholes for easy access whereby the filling of any one compartment may be removed without disturbing the contents of the remaining com- partments. On leaving this tower the gas passes to a condenser, which is generally of the mnlti- tublar water cooled type, where more tar is dropped, after which the gas passes to a relief holder and treated further in other scrubbing and purifying plant. LINING AND REPAIRS. When a water gas apparatus has been run for a certain period, it is necessary to let it down for repairs to generator lining and renewing the checkerbrick in the carburetter and superheater. This period varies according to condition and the engineer's opinion, but in a general way may be taken at 1,000 hours. In letting down the machine, however, the temperature should be allowed to lower gradually to prevent rapid con- traction, and it is best to kill the generator fire slowly with steam before drawing it, and allow- ing cold air to enter a hot machine. When the set has finally cooled off a careful examination should be made of the inner firebrick lining of the generator, particularly around the cleaning 36 Elements of Water Gas doors, where it usually wears out quickly, and the necessary repairs made with a very close joint, using as little fireclay as possible between the bricks. The doors are generally built up with arches and blocks over a cast iron sleeve, and in such a manner as to enable the sleeve to be removed when it burns out and replaced with a new one from the exterior of the machine. Special care should also be given to the brick work around the charging door, as these are lia- ble to be knocked out by bars and shovels when clinkering and charging, and one crevice may let down more bricks and cause the neck casting to be burned or cracked. It is then necessary to give some attention to the carburetter and superheater, which requires a renewal or cleaning of the checkerbrick. In the injection of oil into the carburetter practi- cally no design of spray reach their maximum efficiency and the brick at the top of the chamber where the oil enters are generally coated with lampblack or splintered by the force of the injec- tion. In any case the brickwork becomes more or less saturated with oil, which burns to carbon and finally does not take up and give out the heat necessary for the economical working of the plant, and all the checkerwork should be removed by way of manhole doors provided and Elements of Water Gas 38 Elements of Water Gas thoroughly cleaned or replaced with new bricks. Usually ordinary firebrick are used, and these are placed on their edges in rows at right angles to each other with a space of one and one-half to two and one-half inches between adjacent rows. The rows of each tier are so placed that each comes directly over the space left between the two rows of bricks running in the same direc- tion in the second tier below. This is seen in Fig. 10, where the longitudinal rows of bricks in tier 1 comes directly over the spaces between the rows of tier 2, and the rows in tier 3 come over the spaces in tier 4, and also tiers 1 and 2 come over spaces in tiers 3 and 4 running in the same direction, which give the gases a wave- like motion throughout the chamber. CLEANING THE STANDPIPE. The off-take pipe, which connects the super- heater to the wash-box, gradually becomes coated with carbon deposits, and an unusual back pres- sure will be seen on the operator's gauge board when the coating becomes excessive. When this occurs, the hand hole doors are removed, and the carbon cleaned off by means of bars, caution being taken to prevent the carbon from falling in the wash-box by placing a tray in the bottom Elements of Water Gas 39 cleaning door of the standpipe. It is also neces- sary to clean out the wash-box occasionally, and it is advisable to open the outlet valve at the bottom and wash out the heavy tarry matter about once a week. CHEMICAL OBSERVATIONS. Water is composed of two parts of hydrogen and one part of oxygen, and the process of obtaining gases by the decomposition of water vapor or steam is known as the "Water Gas Pro- cess" in view of the fact that three-fifths of its weight and three-fourths of its bulk consists of the hydrogen and oxygen which previously con- stituted water H2O. It has been repeatedly proven in chemical research that steam can not be broken into its component parts by the direct action of heat alone, but when subjected to high temperatures in the presence of reducing agents which have a stronger affinity for the oxygen than the hydrogen with which it is combined, the oxygen will combine with the reducing ele- ment and liberate free hydrogen. On this theory the water gas process is founded, and the reducing element is carbon con- taining matter, usually coal or coke. The reac- tion is brought about by subjecting the hot fuel to the influence of an air blast wherebv tne 40 Elements of Water Gas oxygen of the air combines with the carbon of the fuel to form carbon monoxide (CO) or car- bon dioxide (CO2) according to the proportion of oxygen available. The combination of the carbon and oxygen may occur in different pro- portions to form different gases, according to the following conditions. In the presence of an excess of oxygen burn- ing carbon saturates itself with two atomic pro- portions of oxygen, and forms the gas CO2. This reaction is exothermic and completes the com- bustion of the carbon with the evolution of 14,500 British Thermal Units (B. T. U.) per pound of carbon, taking two and two-third pounds of oxygen and forming three and two- third pounds of carbon dioxide. This reaction being complete is known as the first law of com- bustion. In the second law of combustion the supply of oxygen is insufficient to completely saturate the carbon, and the excess carbon will partially satisfy its affinity for oxygen by combining with one atomic proportion or robbing saturated car- bon of one of its oxygen atoms, for instance, carbon dioxide passing through heated carbon will be reduced to carbon monoxide, as follows: CO2+C=2CO, with an absorbing of 5,880 B. T. IT. per pound of carbon. Elements of Water Gas 41 If the carbon monoxide is then brought in contact with an excess of oxygen, the third law of combustion takes place to carbon dioxide with an evolution of 10,190 B. T. U. per pound of carbon. In the above it is seen, then, that in the first law of combustion one pound of car- bon takes up two and two-third pounds of oxygen, and forms three and two-third pounds of carbon dioxide with an evolution of 14,500 B. T. U. In the second law the CO2 is reduced by the second pound of carbon with an absorb- ing of 5,880 B. T. U., resulting in the formation of four and two-third pounds of carbon monoxide with the total evolution of 8,620 B. T. U. In the third law the CO takes up another atomic proportion of oxygen and produces complete combustion with the evolution of 20,380 B. T. U. and the formation of seven and one-third pounds of carbon dioxide, which makes the total heat evolved from two pounds of carbon as 29,000 B. T. U. In the elementary study of the carburetted water gas process in this chapter, it has been seen that a blast of air is first admitted to the generator when the excess of oxygen combines with carbon and the first law of combustion takes place. The CO2 gases thus formed then pass up the bed of fuel in an excess of carbon 42 Elements of Water Gas when the gases are reduced to CO, which con- stitutes the second law, and these are passed to the carburetter to be met by another blast of air when the third law of combustion takes place and completes the heating period of the process. In the decomposition of the steam in the gas- making period there is absorbed 4,340 B. T. U. per pound of carbon, which generates approxi- mately 62 cubic feet of gas with a calorific value of approximately 300 B. T. U. The value of this gas, however, is too low for domestic purposes, and the purpose of the carburetter is, therefore, to generate gas of high illuminating value and thereby enrich the blue water gas. The compo- sition of the oil gases may vary with different conditions and qualities, and a typical analyses before and after enrichment is as follows : Carburetted Blue Water Gas. Water Gas. Hydrogen (H) 51.00 30.40 per cent. Methane (CH4) 0.50 16.90 Hydrocarbons 0.00 7.25 Carbon monoxide. . . .40.00 29.00 " Carbon dioxide 5.50 2.05 " Oxygen (O) 0.00 0.20 " Nitrogen (N) 3.00 5.10 " Elements of Water Gas 43 The consumption of fuel coincident with these figures will be about 35 pounds of coke and 3.33 gallons of oil per 1,000 cubic feet of gas, with a candle power of 20 or heating value of 580 R T. U. CHAPTER III. STANDARD DOUBLE SUPERHEATER. UP AND DOWN RUNS. In the preceding chapter the reader has been led into the elements of the internal combustion or intermittent system, and it will now be to advantage to illustrate a standard type of machine in which modern methods are employed. The following descriptions are not confined to any one particular plant, but embodies the most interesting features of various designs. In the early developments of the intermittent process the steam used in the generator always entered beneath the grate and passed upward through the fuel bed to the carburetter. This, however, resulted in the lower part of the fire being cooled considerably, and a down or reverse run was occasionally adopted to overcome this difficulty. After continued application of the down run it was found that it had several effects on the fuel 44 Elements of Water Gas bed, the foremost of which may be summarized as follows: (1) It reduced labor in clinkering and in picking out comparatively large pro- portion of unburnt coke. (2) It effected a saving in fuel by burning small coke that otherwise fell through the grate bars. (3) It made it possible to vary the height of the zone of intense combustion, and allow the use of a wider range of fuels. (4) It enables the temperature at the top of the fire to be better controlled, and con- sequently a better control in tempera- tures in the carburetter and super- heater. In the early attempts the down runs were made about once in every six, but this has been increased to one in every three or less, according to the nature of the fuel used. In the up run the gases leave the generator at the top, and in the down run at the bottom, each outlet being con- trolled by valves which are linked together so that one opens when the other closes. The top valve is generally known as the hot valve, in view of the fact that burning gases pass through it during the air-blasting period, and it was until recent years necessary to water cool it to pre- Elements of Water Gas 45 46 Elements of Water Gas vent overheating and eventual cracking. In modern apparatus, however, the metallic com- position of this valve is capable of withstanding the heat and a dry valve is now employed. One of the most common means of connecting the top and bottom outlet valves is illustrated in Fig. 11, in which 1 is the top outlet for the up runs, 2 the bottom outlet for the down runs, 3 a counterbalance weight which serve to equal- ize the load in either direction, and 4 a dust catcher which collects solid matter carried over in the gas, and thereby prevents such from enter- ing the carburetter. The hot valve is also pro- vided with an ash pocket (not shown) for col- lecting solid matter which is liable to interfere Avith the seating of the valve, and this, in con- junction with the dust catcher, should be cleared every few days to ensure proper seating of valves and a free passage of gas. CENTRAL BLAST AND AIR-COOLED OIL SPRAY. An interesting feature in one design of plant is the arrangement of the blast pipe entering the carburetter, by which a more uniform heat is obtained in the top of the chamber, and also has the effect of keeping the oil spray cool during the blasting period when oil is not being passed Elements of Water Gas 47 through it. In this arrangement Fig. 12, the blast gases come from the generator at 1, and the secondary air blast enters the carburetter at 2, which effects combustion directly in the center of the chamber, and thereby produces a more even distribution of heat over the surface of the checkerbrick. The oil spray 3 is also kept cool by this arrangement, as combustion does not take place until the secondary air meets the blast gases in the top of the carburetter. 48 Elements of Water Gas OIL HEATER. In certain climates it is advisable to heat the oil before passing it into the machine, and this has been done in various ways. One method that has been largely used was to place a coil of pipe in the gas off-take between the super- heater and wash-box and pre-heat the oil by pass- ing it through the coil while the hot gases were passing in the opposite direction. These heaters, however, gave considerable trouble with stop- pages, and the coil became coated with lamp- black, which reduced the efficiency considerably, and in due course the method was abandoned for the simple modification illustrated in Fig. 13. In this heater the cold oil is circulated around a coil of steam pipe in a suitable vessel, which is made of cast iron and is provided with a steam inlet 1, a coil of pipe 2, a steam outlet 3, oil inlet 4, and oil outlet 5. A vapor chamber 6 is also provided at the top of the heater, which main- tains a constant pressure on the hot oil line by minimizing the pulsations of the oil pump. Pre- vious to entering the heater the oil is measured cold by passing through a meter, and the steam condensed by passing through the coil of pipe is led to a steam trap. Elements of Water Gas 49 50 Elements of Water Gas AIR METER. One of the most important developments in water gas manufacture was the introduction of the air and steam meters, by which accurate measurements of the fluids employed could be made and thereby the process put on a more scientific basis. Whilst different designs of meter have been used, the principles employed are practically the same, the essence of which is illustrated in the following descriptions. The application of the air meter to the car- buretted water gas machine is shown in Figs. 14 and 15, in which 1 comprises the generator, 2 the carburetter, 3 the superheater, and 4 the wash or seal box. The air blast pipe 5 is pro- vided with the usual branches, 6, 7, 8 to 1, 2, 3, each of which is provided with a supply regulat- ing valve 9. The essence of the meter lies in the venturi tubes 10, which are placed in each air supply, and indicates the volume of air passing through per second or other unit of time by rea- son of the different pressures that simultane- ously exist in the most contracted area or throat and the larger area on each side of the throat, and since this indication is continuous, it enables the difference to be transmitted to a suit- able indicating gauge. It is now a well estab- Elements of Water Gas 51 52 Elements of Water Gas lished fact that the economical operation of a water gas set requires that each set of the pro- cess must be performed in a manner that has been ascertained to be the most efficient, and it is necessary that a pre-determined volume of air- is introduced in each blow in order to raise the apparatus to the correct temperature for the reception of a given quantity of oil and steam. For instance, if a larger volume of air is passed through the generator than what is needed, an unnecessary consumption of fuel will result, whilst an insufficient quantity of air will fail to raise the machine to the required temperature for gas making. It is evident, then, that the temperature of the set is substantially propor- tional to the quantity of air introduced, and the volume of gas made is proportional to amount of steam and oil capable of being decomposed or vaporized by the temperature of the machine. Prom the above it is clear that the admission of a pre-determined volume of air is necessary for the economical operation of the set, and the ven- turi tubes 10, shown more fully in Fig. 15, are connected to a gauge on the operating floor by means of pipes 12 and 13, which enable the oper- ator to know at a glance the volume of air pass- ing to the set. The gauges are provided with pet cocks 14, valves at 15, and a graduated scale Elements of Water Gas 53 54: Elements of Water Gas 16 for convenient reading. In operating the set with the guidance of this meter, the attendant knows in advance the volume of air that is to be introduced to the respective parts of the appa- ratus, and he can, therefore, accomplish this by reference to the scale 16, and the adjustment of the valves 9 accordingly. STEAM METER. The object of the steam meter is to provide means for controlling the quality and quantity of the gas produced by enabling the operator to introduce a definite volume of steam into the generator per volume of gas required in conjunc- tion with a pre-determined volume of air. For instance, if the set is such that it is required to generate 10,000 cubic feet of gas per run of four minutes, the air meter will be set in accordance with this to guide the operator in admitting suf- ficient air to raise the temperature of the fuel to a degree at which it will decompose sufficient steam for the production of 10,000 cubic feet of fixed gas, and the steam meter will be set in accordance with it to allow an accurate volume of the fluid to be admitted, and thereby prevent the fire from being cooled too much or insuffi- ciently. It has been found in practice that it Elements of Water Gas o 55 2 * 50 Elements of Water Gas requires approximately 30 pounds of water in the form of steam per 1,000 cubic feet of car- buretted water gas, and in the example referred to, where 10,000 cubic feet needs to be produced in four minutes, the fuel would require sufficient steam per minute for the production of 2,500 cubic feet, which is 30X2.5=75 pounds. With these pre-determined facts the respective meters are set so that the attendant knows exactly what is required in the apparatus, and thereby oper- ates the machine -accordingly for a desired result. One of the best and simplest forms of steam meters is illustrated in Fig. 16, in which 1 is the generator, with the usual charging and off- take ports, 2 is a gauge or metal dial, and 3 is the meter tube through which the steam used in the generator passes. This tube consists of an internally bell shaped body, 4, Fig. 17, having an inlet 5, and outlet 6, and is connected at its inlet to pipe 7 communicating to the meter dial, and at its outlet to the generator by way of 8. The steam is supplied by way of pipe 9 through valve 10 and automatic pressure regulator 11, which adjusts variations in boiler pressure and main- tains a constant pressure at the meter tube. The regulator may be of various design, and a con- venient one as shown at A, Fig. 16, consists of Elements of Water Gas S 57 58 Elements of Water Gas an adjustable weighted spindle 12, connected with a diaphragm 13, and having valves 14 and 15. This device is connected to pipe 16, which leads to meter tube 3 and keeps the pressure of the steam constant on the inlet side of the tube and appropriate for causing 2 to indicate the required volume passing through per unit of time. The theory of this measurement is based upon the fact that the quantity of flow through tube 3 is directly proportionate to the absolute pressure of the steam on the inlet side of the meter tube, and inasmuch as the gauge 2 indi- cates the pressure, it also indicates the quantity of flow of steam entering the generator per unit of time, and under these conditions it is only necessary for the attendant to operate the valve 10 when commencing or ending a run. Occa- sionally, however, the steam regulator is omitted when it is necessary to operate the valve to a position corresponding to the amount of steam required as indicated by the gauge. AIR REGULATOR. One of the latest developments in the progress of water gas manufacture is the air regulator, the object of which is to automatically increase the quantity of air supplied for the combustion Elements of Water Gas 59 of carbon monoxide to carbon dioxide in the carburetter as the quantity of the former gas increases. In the heating or air blasting period of the apparatus the composition of the gases given off from the generator varies during dif- ferent portions of the blow whilst the fuel is being raised to its highest state of incandes- cence, and invariably gives off a greater propor- tion of combustible gas as the temperature con- tinues to rise and liberates carbon more rapidly. Under the average conditions it has been found that the percentages of carbon monoxide in the producer gases from the generator varies from 5.00 per cent, after 25 seconds of blasting to 20.00 per cent, after 200 seconds of blasting, and in order to effect complete combustion of the gas it is evident that the quantity of air admitted to the carburetter needs to increase in accord- ance with the increase of combustible matter, whilst, at the same time, an uncalculated in- crease, such as raising the valve at intervals, is liable to cause an excess of air to be admitted at certain portions of the blow, and thereby cool the checkerbricks and seriously affect the eco- nomical operation of the plant. An interesting and simple device used for the purpose of controlling the necessary quantity of air is illustrated in Fig. 18, in which 1 is the Elements of Water Gas Elements of Water Gas 61 secondary air line leading to the carburetter, and is provided with valve 2, which is connected by links and levers to operating mechanism on holder 3. The holder is provided with a bell 4, connected by rope 5 to the operating handle 6 of a damper 7, arranged in the air line 1. The interior of the bell is connected by means of a three-way cock 8 to a pipe 9, which leads to the air line or to pipe 10, which leads to the atmos- phere, each branch being provided with regu- lating cocks 11. A counterweight for the damper 7 is provided at 12, and the three-way valve is connected to valve 2 by means of link 13, bell crank 14, link 15, and handle 16, so that the operation of valve 2 will also operate the three- way valve 8. In the run of gas when the gate valve 2 is closed the position of the three-way cock is such that the bell 4 is in communication with the air line 1, which results in the bell being raised to the stops as indicated by dotted lines, and simultaneously causes the counter- weight 12 to close the damper 7 by means of the lever 6. At the end of the run of gas the gen- erator air blast is opened, and a few seconds later the carburetter blast valve 2 is opened, which in turn operates the cock 8 so that the bell is put in communication with the atmosphere by way of pipe 10, which causes air to gradually 02 Elements of Water Gas escape and the bell to descend. This movement actuates the damper 7 and automatically increases the supply of air through valve 2 into the carburetter simultaneously with the increase in temperature of the fuel bed in the generator, and subsequent decomposition of the fuel more rapidly. The speed of descent of the bell can be varied by the adjustment of the cock 11 on line 10, and where it is desired, weights are pro- vided which suspend at various heights from the top frame of the holder and rest on the bell throughout a desired portion of its travel and increase the rate of movement accordingly. A slight modification of this arrangement is illustrated in Fig. 19, in which an additional holder 17 and bell 18 is provided, and has inlet connections 19 to pipe 9 and outlet 20 to the throat of a meter 21 interposed in the blast line. The stem 22 of the holder 18 is connected by a short link 23 with one end of the floating lever 24, which leads to the stem 25 of bell 4 in holder 3, and a link 26 connected with lever 14 is in communication with arm 6 of damper 7. In the operation of this arrangement the bell 4 is in its raised position at the beginning of the blow and the bell 18 in its lowest position, and on opening the blast valve 2 the three-way cock 8 is operated so that the bell 4 descends and opens Elements of Water Gas 63 64 Elements of Water Gas the damper 7 as in the previous arrangement. This action causes air to pass through venturi meter which produces a differential pressure across such meter and tends to raise the bell 18, and in turn close damper 7. It is obvious, then, that by the adjustment of these bells and levers the flow of air can be regulated to any desired portion at any part of the blow, and if the blast pressure in the line increases the differential pressure across the meter will also increase and thereby raise the bell 18 and close damper 7 and reduce the flow of air to the normal requirement. STARTING AND WORKING A SET. The purpose of the double superheater is to increase the contact surface in fixing the oil, and also to carry the blast gases away from the oper- ating floor and thereby minimize the risk of dan- ger to the attendant. This form of apparatus is erected by a number of makers, and a common example is shown in Fig. 20. When a new set is put in operation it should first be carefully dried out by covering the grate bars of the gen- erator with six or eight inches of coke, adding about one foot of shavings and dry wood and a portion of coal or coke. A fire is then started with the charging door of the generator open Elements of Water Gas 65 until a good body of fire has been obtained, after which the charging door may be closed and the heat allowed to pass through the machine, care being taken to effect a gradual drying by check- ing the draft at the ash pit doors. If the time is available it is advisable to allow two or three days in drying out a new set, although, if neces- sary, this period can be reduced to a few hours by careful management without injury to the plant. When the set is being dried gradually the body of fire should be kept at about two feet, and each time fuel is added care must be exer- cised to light the gases at the charging door before opening wide, or an explosion will result. When the shell of the carburetter is warm the machine may be put under blast, and in prepara- tion of this the fire is charged well up and the clinkering and ash pit doors securely fastened. After the blast has been on for more than ten minutes, the bottom steam valve should be slightly opened to prevent overheating of the brickwork in the lower part of the generator, and when a flame can be seen in the top of the generator through the sight cock, the carburetter blast valve should be opened, care being taken to open only very slightly until a flame appears in the top of the chamber. The carburetter being lit off. it is then advisable to light the gas 66 Elements of Water Gas jet or pilot light at the stack valve on top of the superheater, as this serves as a guide to the attendant by igniting unburnt gases as they issue from the machine, and when a blue flame is seen at the stack valve it is necessary for the attendant to increase the supply of air in the carburetter and effect complete combustion within the machine. When the carburetter has reached a red heat it is time to look for a blue flame in the bottom of the superheater, and when such appears the superheater air blast should be raised and when ignited the carburetter blast should be lowered to allow a portion of combus- tible gases to be burned in the superheater. A method sometimes adopted in lighting off the superheater is for one man to pass a red hot bar or pipe through the sight cock while another man opens the air supply, but this method is not to be advised in view of the fact that the man holding the pipe is in danger of flying sparks when the gas ignites, and it is certainly not necessary to an experienced gasmaker. After the superheater has reached a red heat, the air blasts can be cut off and a run of blue gas made by passing steam through the gene- rator, and this should proceed by first closing the superheater air blast, then the carburetter, and finally the generator, after which the steam Elements of Water Gas 68 Elements of Water Gas valve is opened slightly, the stack valve closed, and the steam valve adjusted according to the gauge. It may here be stated that the operator's gauge board is usually placed in a position so that it can be seen at all times during the operation of the plant, and consists of a series of water col- umns, Fig. 21, which indicate the pressure of the machine in inches at different parts in the order of generator 1, carburetter 2, superheater 3, and seal box 4, the highest pressure being seen on the generator gauge and decreasing in order to the seal box. The board is also pro- vided with steam gauges or meters 5 and 6 for up and down runs, respectively, air meter 7, oil pressure gauge 8, and indicating pyrometer 9, whilst on a stand near the oil meter is placed. When the run of gas is put on the operator should immediately observe the pressures indi- cated, and if an unusual pressure is seen, the steam should be immediately cut off until the cause has been ascertained, which generally may be a closed valve or an excess of condensation in the drip pot between the machine and relief holder. It is advisable to see, at this point, that water is passing through the scrubber and con- denser, and special care should be taken in see- ing that water is passing into the seal box before Elements of Water Gas 69 the run is taken off, or gas will return and escape into the atmosphere when the stack valve is opened. After two or three runs of blue water gas have been made the temperature of the car- buretter should be high enough to break up the oil to the required extent, and on the third or 70 Elements of Water Gas fourth run the oil is admitted, when a greater pressure will be seen on the water column gauges. About one-half minute before the end of the run the oil is cut off, and the spray wiped out by passing steam through it for a few sec- onds. When the machine is in full working con- dition the operator should pay frequent atten- tion to the nature of the overflow at the seal pot for the appearance of lampblack, which is seen when the heats are too high, or for light tars when the heats are too low. OPERATING CONDITIONS. The length of the air blast and runs of gas depend on various conditions, such as the nature of fuel used, power of the blasting plant, quality of gas desired, and quality of fuels used. In the early stages of the internal combustion system it was customary to blast for 20 minutes or more and make runs of gas for 30 minutes, but with the development of the process the tendency has been to reduce the length of the cycle to the present day rate, which may be taken on an aver- age of three minutes' blasting and five minutes' gasmaking, with a blast pressure of 20 inches of water on the gauge. The steam is admitted in accordance with the steam meter, whilst air is Elements of Water Gas 71 admitted to the carburetter in accordance with the differential air meter, and a pressure of about 45 pounds per square inch is kept on the oil line. The temperature of the carburetter and superheater varies, of course, with the grade of oil, and may be taken, on the average, at 1,400 F. in the carburetter, with about 100 F. less in the superheater at the beginning of the run. The gasmaker is provided with printed sheets to record the times of operation of the machine, check the oil meter at the end of each run, record the amount of fuel, and frequently record the temperatures of the carburetter and superheater. In the smaller works he has also frequently to check the reading of the station meter about every hour, and compute the amount of gas per run with the quantity of oil per 1,000 cubic feet. CHAPTER IV. THE VERTICAL APPARATUS. A design of apparatus that has met with marked success is the vertical type, the most important of which is the Williamson's. In this plant the carburetter and superheater are arranged in a vertical plane with the generator, the object of which is simplicity of construction and operation, reduction of ground area, and a 72 Elements of Water Gas **: ** Elements of Water Gas 73 more thorough uniting of vapors in the car- buretter and superheater by passing through a deeper surface of checkerbrick. In Fig. 22 is shown a sectional elevation of one form of apparatus in which 1 is the air blast line supplying pipe 2, which is provided with a valve 3, which is usually of the ordinary gate type. The pipe 2 leads into header 4, which in turn communicates with the generator by means of a series of partitions 5, each of which are pro- vided with a series of slots for projecting jets of air into the ash box 6 beneath the grate of the generator, which rests on a cross bar 7, sup- ported on the wall. The outlet of the generator is provided at 8 and is controlled by valve 9, which is of special construction, as described later. A connection 10 leads into the mixing chamber at the top of the carburetter, and a port 11 is provided in the said chamber for the admis- sion of secondary air, and there is also an oil spray 12 connected to a pipe 13 through which the oil is passed. The carburetter 14 is filled with checkerbrick as in the usual manner, and has communication at its lower end through passages 15, Fig. 23, into receiving chamber 16, into which the gases descend and commingle before entering the superheater. The dividing wall 17, which separates the carburetter from 74 Elements of Water Gas the superheater, extends the whole length of tne chambers, and has openings 18, which furnish communication between the receiving chamber 16 and discharge chamber 19, the latter of which Elements of Water Gas 75 leads into superheater 20 by way of passage 21. The superheater is filled with checkerbrick as in the standard type, and the fixed gases are dis- charged into chamber 22, which leads to seal box 23 by way of pipe 24. The shell of the carbu- retter and superheater is of the usual type and is a continuation of the generator shell, and is provided with a lining of firebrick or other refractory material, and is separated from the wall of the generator by means of an arch of special design. The blast gases leave the machine through passage 25 and stack valve 26, and pass into the atmosphere through the stack 27. The stack valve is mounted on wheels and rests on a track 28, supported by swinging links, the lower ends of which are mounted in pivot plates on the top binding plate of the wall of the machine. The stack valve or cap can be moved by means of levers which are connected to a pivot of one of the said links, and is actuated by a chain so that by moving the lever downwards the rails and cap are elevated, and by moving the lever upwards the rails and cap are lowered. In order to move the cap at the end of the blow and run there is provided a draw bar 29, which is pivoted to ears on the cap, and connected by links 30 with a rock shaft mounted in ears, and having connected therewith a lever 31, which is moved 76 Elements of Water Gas Elements of Water Gas 77 by a chain running over a pulley attached to a girder at the top of the building and another pulley on the operating floor. In some installa- tions of this apparatus the construction of the carburetter and superheater is slightly modified, as illustrated in Fig. 24, where, instead of the blast gases entering the mixing chamber at the top of the carburetter, they are led through out- let pipe 8 on each side of the generator, by way of valves 9, and into chamber 13 on one side of the apparatus and chamber 19 on the other side, the said chambers in this design being separated entirely by a solid wall 17. The chamber 13 con- stitutes the mixing chamber for the oil and water gas, and leads to carburetter 14 and receiving chamber 16, and down superheater 20, which is in communication with chamber 19, from which the gas passes to a seal box. The operation of this design is the same as in the previous arrangement, but different in the flow of gas in that the carburetted water gas passes up the carburetter and down the superheater, and the blast gases pass up both chambers 14 and 20 through valves 9 simultaneously, and out of the stack by way of 25. At the end of the blasting period the pipe 8a, which leads to lOa, is closed, which causes the water gas to pass oft 78 Elements of Water Gas by way of 8 and 10 and up the carburetter and down superheater. WATER SEALED VALVE. A novel feature in this apparatus is the con- struction and arrangement of the outlet valve from the generator, which is frequently known as the hot valve, in view of the fact that burning gases pass through it on the way to the car- buretter. Briefly, the valve shown in connection with Figs. 22 and 24 consists of an inclined plate and a peripheral rim with a seating face on the solid plate which coacts with a seating face around the pipe, and is located in a casing of ordinary construction, which may be water- cooled if desired. However, in the later develop- ments of this apparatus a specially designed valve has been adopted, which is illustrated in Figs. 25 and 26, in which 1 is the outer casing communicating with the adjacent ends of pipes 2 and 3, Fig. 27, which leads from generator to carburetter. This casing is of spherical shape, and through its wall the nozzle 4 extends upwardly, as shown in Fig. 25. In the opposite walls of the casing and extending inwardly therefrom are stub shafts 5 and 6, the latter of which is connected with a lever 7, Fig. 27, and Elements of Water Gas 79 secured to the inner ends of the shafts 5 and 6 is a hood 8 of semi-circular shape in longitudinal cross-section, which is adapted to swing into and out of the position in which it extends over 80 Elements of Water Gas the open ends of the nozzle 4. The casing 1 pro- vides a receptacle for water, which enters at 9 and overflows therefrom through a pipe 10, com- municating with the casing at 11, and the upper Elements of Water Gas 81 82 Elements of Water Gas end of the pipe 10 is connected with gas off-take 2 by way of 12 for equalizing the pressure on the water, which determines its level in the cas- ing. It is necessary that the level of the water is maintained at a point between the top of the nozzle 4 and lower portion of the hood 8 when in the position shown in Fig. 25 for closing the valve in order to form a water sealed valve capa- ble of being opened by swinging the hood upon its journals to a position into which it is sub- merged in the water for uncovering the top of the nozzle as shown by dotted lines, Fig. 25. The valve 13, Fig. 27, is of the same construc- tion as valve 14, and receives its supply of water for producing the seal from the valve 14 by way of pipe 10 and overflows at 15. On the outer surface of the valve 14 there is provided a pas- sage 16, which communicates at its lower end with pipe 17 and at its upper end with pipe 2, and thereby forms a continuous passage between the two pipes. The two valves are connected together by a link 18 and lever 19, so that one valve opens when the other closes. When the generator is put on the down run the valve 14 is closed by means of a wheel, which simultane- ously opens the bottom valve, and allows the gas to pass upward to pipe 2 by way of passage 16 into the carburetter. The nozzle 4 of the upper Elements of Water Gas 83 valve is lined with firebrick or other refractory material to prevent rapid deterioration by the burning gases during the blasting period, and it is obvious that the hood or valve proper 8 moves in a water seal and prevents the wearing of metal, which is usually very rapid under the influence of the intense heat, and simultaneously insures a substantially gas tight joint. CHAPTER V. TWIN GENERATOR SYSTEMS. In the twin-generator system the object is to minimize the percentage of carbon monoxide in the blast gases, and that of carbon dioxide in the water gas, and it is usual to employ two gen- erators connected together at the bottom and allow the air blast to pass upward through them in parallel, whilst the steam during the run is passed up one and down the other alternately. In the earlier installations of this system, how- ever, it was found that the output of gas per square foot of grate area was considerably reduced, and various modifications have been tried to increase the efficiency of the system in this respect to equal that of the single generator system, 84 Elements of Water Gas CONVERTIBLE APPARATUS. One design of apparatus possessing a number of advantages over any previous attempts con- sists of two generators connected by a common bottom, in which the gasmaking steam in proper proportions is passed simultaneously either all upward or downward, or serially in either direc- tion, supplemented by steam for the second gen- erator. The object of this design is to enable the plant to be worked on the single generator system, and simultaneously obtain the advan- tages of the twin system, according to the will of the operator, and the valve mechanism and link motion is such that the plant can be changed automatically from the single to the twin system by the movement of a single lever. In Fig. 28 the generators 1 and 2 are con- nected by a conduit 3, which is provided with an optional gas outlet 4, Fig. 29, controlled by valve 5, in addition to the outlet pipes and valves 6 and 7, and 6' and 7'. The valves 7 and 7' are actuated by levers 8 and 8', Fig. 30, which are connected to shafts 9 and 9' by arms and links 10 and 10'. These shafts are coupled together and connected to valve 5 by means of yoke 11 and link 12. The lever 8" is operatively con- nected by link 13 to clutch 14, whose members Elements of Water Gas 86 Elements of Water Gas 14', 14", and 15, are splined on the shafts 9 and 9' and coupled by snivels to the connecting link 13 so that the clutch members travel along the shaft and respond to the movement of the lever 8". The members 14', 14" and 15 are adapted to couple simultaneously the shafts 9 and 9' with the yoke 11 at 15' and 15", and with each other at 16, so that the valves 7, 7' and 5 must all work together ; 7 and 7' being opened when 5 is closed until the clutch is disengaged, when the shafts are free to rotate separately. The blast valve 17 is operated by wheel 18, through gearing 19, and controls the admission of air to the bottom of the two generators for upward blasting in par- allel, when the blast products pass off through outlets 6 and 6'. On the primary steam supply 20 are placed a series of distributing cocks 21', 21", 22', 22", which are connected with shaft 9, and operated simultaneously with the valve 7 so that 21' and 22' and 21" 22" are opened when the valve 7 is opened. The valves 23', 23", 24' and 24" are connected to shaft 9', so that 23' and 23'' are closed, and 24' and 24" are opened when valve 7' is opened. The steam conduits are pro- vided at 25, 25', 25" and 26', 26", and 26' is formed with a dual connection to the primary steam supply, and the valves 21" and 23" are on one branch of the connection, with 22' and 24' Elements of Water Gas 87 88 Elements of Water Gas on the other. The steam entering the generator is accurately controlled by regulating cocks and meters 27, 27' and 27", and 28, 28' and 28", of which 27 and 28 control the upward supply in parallel, and 27' and 28' the downward supply. In serial steaming, however, it is necessary to increase the supply, and this is provided by the regulating cock 29 on the loop connection 26", which automatically adds to the top of either generator any desired proportion of the quan- tity of steam that is available for the top of the other generator, whilst a supplemental bottom steam may be had if desired through 29' and 29" in conduit 26'. The relative position and object of the valve mechanism having been thus described, it will be seen that independent regulation is provided for each supply, and that the setting of any may be varied without altering the others. If the operation is now followed it is seen that the disengagement of clutch 14 by lever 8" will enable the plant to be steamed upwards in paral- lel or serially in either direction with optional bottom steam, according to the position of the valves 7 and 7'. If upward steaming in parallel is desired, the valves 7 and 7' are both open, and steam from the pipe 20 passes through regulat- ing cock 27, steam cocks 22", 24", 21" and 24', Elements of Water Gas 89 through conduit 25 controlled by them, and meter 28 into conduit 3, and upwards through generators. If it is then desired to steam serially, for instance, down through generator 1 and up generator 2, the valve 7 is closed by the movement of lever 8, which simultaneously closes steam cocks 22" and 21", thereby closing conduit 25 to the bottom of both generators, and, at the same time, the closing of these valves is effected, the cocks 21' and 22' are opened, which admits steam to the top of generator 1 through conduit 25' and meter 28', this supply being supple- mented at the bottom, if desired, through regu- lating cocks 29', steam cocks 22' and 24', the con- duit 30, meter 29", into conduit 3, and up through generator 2. In reversing the direction of serial steam the gas outlet 7 is opened, which closes steam cocks 21' and 22', and opens 21" and 22", and the gas valve T is closed, which simul- taneously opens steam cocks 23' and 23", and closes 24' and 24". This order allows steam to pass through cock 23' to top of generator 2 by way of cocks 27" and 29, conduit 25' and meter 28", supplemental bottom steam being admitted through 29', 21" and 23", the conduit 26', meter 29", into conduit 3 and up generator 1. If it is then desired to change the operation of the plant from the alternating series to a pair 90 Elements of Water Gas Elements of Water Gas 91 of generators steaming together in either an upward or downward direction, the lever 8" is moved back to the position shown by dotted lines, which causes the clutch 14 to couple the shafts 9 and 9' with yoke 11 at 15' and 15", and with each other at 16, and simultaneously causes the gas outlet valves 7, 7' and 5 to work together, 7 and 7' being opened while 5 is closed. In this position the up run will proceed as previously described, and on moving one of the levers 8 or 8' to the dotted position, the gas valves 7 or 7' will be closed and gas valve 5 will be opened. The steam cocks 21', 22', 23', and 23" will at the same time be opened and 22", 24' and 24" will be closed, whereby steam will be directed to the tops of both generators for the down run in parallel, when the gas will leave the gen- erators by way of conduit 3 and valve 5. It is seen, then, that the movement of one of the levers 8 or 8' will alternate the generator from the up and down run in parallel, and the move- ment of the lever 8" will automatically change the working of the plant from parallel steaming to serial steaming characteristic to the twin- generator system. It may here be noted that the valve 5 is of special design so that any excess pressure in 92 Elements of Water Gas the generators will cause the disc to be raised, and thereby act as a relief valve. The twin system has not been very largely employed, although it may be said to possess certain advantages, and in the writer's opinion a design of plant particularly adapted to meet the requirements will in course of time super- sede the single generator system. It has been well said that one of the most important items in the manufacture of carburetted water gas is the control of the generator fire, particularly in keeping it in a healthy condition, and every gas engineer knows that after four or five hours' continuous operation the efficiency of the plant is reduced by the accumulation of ash and clinker, which also interferes with the make per unit of fuel. The removal of this clinker causes the entire plant to be shut down for a period, which may vary from 10 to 150 minutes, accord- ing to the condition, and where water gas is made exclusively, as in many districts in the United States, a shut down period of two hours or more at an inconvenient time of the day often causes the holder supply to be considerably reduced, and also interferes with the normal working temperatures of other parts of the appa- ratus. If, however, a satisfactory design of twin generator was adopted, it would enable the plant Elements of Water Gas 93 to continue working on the single generator sys- tem while the condition of the other generator was made healthy, and increase the output of the machine by at least 10 per cent, on the same carburetter and superheater at a comparatively small outlay of capital, and simultaneously com- bine the advantages of the twin system with those of the single system when both generators are being operated together either serially or in parallel, as illustrated in the previous example. CONTINUOUS PROCESS. A modification of the twin-system which pos- sesses some very interesting developments is that in which two generators are operated alternately in conjunction with a series of retorts and an oil fixing chamber. The objects of this apparatus are : (1) To enable gas to be made continuously. (2) To allow the use of cheaper grades of soft coal. (3) To effect distillation of the coal in an atmosphere of water gas, and thereby take up hydrocarbons that otherwise break down to tar. 94 Elements of Water Gets (4) To control the temperatures of the dis- tillation chambers by making it possi- ble to use a definite proportion of water gas and air for combustion, under a given pressure and temperature. (5) To enable a constant temperature in the oil fixing chamber to be obtained. This system purposes to have several advan- tages over any previous attempts to carbonize soft coal in conjunction with water gas gen- erators, and its arrangement is such that the water gas generators can be employed with the retorts without the oil fixing chamber and thereby lower the quality of the gas in the event of it being too rich, or the oil chamber can be brought into operation immediately and enrich the gases. It also embodies positive heating of the retorts by employing a definite proportion of gas at definite heating value, and thereby effecting greater uniformity in the working of the plant. In the diagramatic view, Fig. 31, the prin- ciple of the apparatus is shown, and 1 and 1' are vertical retorts arranged within a firebrick setting and provided with a series of flues as hereafter described. The gas leaves the retorts by way of pipes 29 and 29' and pass to pipe 30, where they mix with water gas or carburetted Elements of Water Gas 95 ^ 7 96 Elements of Water Gas water gas. The retorts are continuously charged at 32 and 32', and continuously discharged at 16 and 16' by rotating buckets, and at the lower end of the retorts a series of flues 20, 20', 21 and 21 r are arranged, through which air is passed to receive a primary heating. A boiler provided at 2 for the generation of steam is heated by gases coming from one or the other generators 3 alter- nately and passes steam therein through pipe 4. The second water gas generator stands behind 3 and is, therefore, not seen in the illustration, but is similar in construction as the one shown, and operates alternately with it on a three-minute blast and three-minute run. In this arrange- ment it is evident that one generator is making gas for three minutes while the other is being blasted for three minutes, after which the order is reversed, which results in a continuous flow of gas through pipe 13 from one or the other gen- erator. A portion of the gas entering pipe 13 is passed through valve 12 to pipe 11 to be met by an injection of oil at 10 and into the hori- zontal retorts 8, which extend within the heat- ing flue 7. These retorts are of various dimen- sions, according to the location of the plant and consequent nature of enriching agent, and are about 15 to 20 inches in their cross section, where heavy oil is used, or from 8 to 10 inches Elements of Water Gas 97 where light oils are used. The carburetted water gas emerges from the retorts at 9 and is passed into coal gas main 30 or to a relief holder as desired. The heating of the plant is accom- plished by admitting air from main 5 through branch 6 into generator 3, which results in the formation of producer gases, which are passed up flue 7 from one or the other generator, and raises the temperature of the retorts to the required degree, which is controlled by the initial pressure of the air blast. The arrange- ment of this flue is in a vertical plane with the generators, and the resistance of the gases is thereby reduced to its lowest degree, and by employing an high pressure blast and low fuel bed an excess of oxygen is created in the gen- erators which makes it unnecessary to employ secondary air in the carburetter, although means are provided at 31, if desired. The products of the combustion are then passed into chimney 28 or to a waste heat boiler. In the path of the burning gases are placed a series of flues, 20, 21, 20' and 21', through which air passes and receives a secondary heating pre- vious to combustion around the coal gas retorts. The path of the air is up branch 17 from main 5 into flues 20, 20', 21, 21', arranged around the lower part of the retorts, and then through the 98 Elements of Water Gas aforesaid flue extensions, which passes through the heating flue 7, and on to the combustion chambers 18 and 19. A portion of the blue water gas fed into main 13 is passed through valves 14 and 14' into pipes 15 and 15', and then to the aforesaid combustion chambers, where it meets the heated air, and the products of combustion pass into flues surrounding the vertical retorts ; 23 and 24 leading from 18 to downward flues 25, and finally into chimney 28, whilst flues 26 and 27 lead from 19 to downward flues 25', and finally into chimney 28'. In following the description of the plant it is evident that the operation of the process is as follows: The generators are caused to produce water gas in the usual manner, part of which is led into combustion chambers for the subsequent heating of vertical retorts, and part of which is passed through a series of smaller retorts in con- junction with oil to be carburetted and fixed, and alternately each generator is caused to produce gases for the purpose of heating the oil retorts and simultaneously giving a secondary heat to air used for combustion around the vertical retorts. The Fig. 31 is somewhat diagramatical and various modifications employing a similar prin- ciple are made ; for instance, in one form the air Elements of Water Gas 99 flues 20 and 21 are not passed through heating flue 7 and the producer gases are thereby used entirely for heating the oil fixing retorts, whilst in another modification the combustion flues 1, t t 4 t ~ \ \ Fig. 32, are divided by a wall 3 and the retorts 2 arranged vertically so that the carburetted water gas passes up one set and down the other, and again the combustion chamber 7, Fig. 31, is divided in the center and filled with a checker- 100 Elements of Water Gas work of bricks to form fixing chambers as in the intermittent process, and each chamber operated alternately in unison with the alternate opera- tion of the generators so that there is always a flow of gas from the carburetting plant, and a continuous distillation of the soft coal in the water gas atmosphere. CHAPTER VI. AUTOMATIC CONTROL. In the early developments of water gas appa- ratus the length of the blasting period was about 20 minutes, and .that of the run about 30 min- utes, and the efficiency of the apparatus was usually about 20,000 cubic feet per square foot of grate area of the generator in 24 hours. The tendency, however, has been to reduce the oper- ating cycle, and this has resulted in increasing the capacity of the set and simultaneously reduc- ing the amount of coal per unit of gas made. At the present time, where apparatus is man- ually operated the cycle is usually about eight minutes, consisting of a three-minute blow and five-minute run, and occasionally it has been reduced to six minutes, in which a two-minute blow and four-minute run is employed. It has been found that this cycle puts an unusual strain Elements of Water Gas 101 * ~* - ' . ' '',* '^ J j * * on a gasmaker, who has to be constantly on the alert in an unhealthy atmosphere, and the influ- ence of the poisonous carbon monoxide, com- bined with the strain of the reduced cycle, has made it practically impossible for a human ele- ment to remain consistent to his post and oper- ate the machine to accurately timed periods, and many engineers regard this as the worst diffi- culty in the economical and scientific operation of water gas apparatus. Personally, the writer has found that the most consistent gasmaker is in the habit of running 10 or 15 seconds above or below the recorded time, and this, when com- puted in a day's results, is liable to considerably effect the coal and oil figures. BLAST PRESSURES. It is evident, however, that many engineers could not, under existing conditions, reduce the six-minute cycle, owing to inadequate blowing capacity, as it requires at least two minutes to get up the heats when the blowing plant is being operated at its maximum capacity, but where the necessary air can be obtained, it has been found that even this cycle can be reduced with advan- tage to three or four minutes in combination with automatic control. 102 Ele r tnent$ of Water Gas The capacity of the blowing plant needed depends, of course, on the size of the machine it has to supply, and it is believed that the greater amount of air that can be passed through the fire in a limited time, the more economical will be the results and the greater will be the capacity of the machine. The highest volume of air passed through the fire within the writer's experience is approximately 300 cubic feet per square foot of grate area per minute, and by this it was able to reduce the length of the blow to 75 seconds, and there is every reason to believe that this volume can be increased with advantage and the blasting period still made shorter. One of the most important advantages of high pressure blasting is that it enables the use of lower grade of fuel, owing to the fact of there being less variation in the temperature of the fuel during the shorter blow. In a fuel contain- ing a high percentage of ash with a low melting point, the ash will fuse into clinker and disturb the efficiency of the fire when a blow of several minutes is adopted owing to there being a wide variation in temperature between the beginning and end of the blow, and if a shorter cycle is adopted the temperature of the fire will not be lowered to the same extent during the run, or Elements of Water Gas 103 need not be heated to the same degree at the bottom of the fire before the commencement of the run. TEMPERATURE CONDITIONS. With the advent of high pressure blasting it was found advisable to reduce the depth of the fuel bed, and thereby correspondingly reduce the resistance. In existing methods where a three- minute blast is employed it is customary to clinker the fire about every 8 or 12 hours, and in the latter part of this period the depth of the clinker and unburnt fuel is usually one foot or more, which considerably reduces the efficiency of the blowing plant, and also reduces the depth of the live fuel bed. With high pressure blast- ing, however, and a lower fuel bed the resistance to the air is reduced, which makes it possible to obtain the necessary temperatures in about one minute, and since the difference in the tempera- ture of the fuel at the bottom is not so great, a less proportion of ash is fused and consequently the bottom of the fire is kept more healthy. When the clinker in the generator is one foot or more in thickness, it is a difficult and laborious matter to remove it, and a cleaning period may take anywhere from 30 minutes to three hours, which consequently reduces the 104 Elements of Water Gas capacity of the set per 24 hours. In the high pressure system, however, where the clinker does not fuse to the same extent, it is found that by shaking the fire about every 25 runs or every 100 minutes, the dead or fused matter can be worked through the grate bars in a comparatively short space of time, it being only necessary to pass a light bar over the grate once or twice. In an experimental test in which the writer is acquainted, the average cleaning time for a period of four weeks was slightly over one min- ute per clean on a system of 25 runs on a four- minute cycle. Under these conditions the fire is kept practically healthy at all times, and the depth of fire can be reduced one foot or more and still be as effective in the decomposition of steam as if the depth was kept seven or eight feet, as in existing conditions. It is also found that in the high blast and low fire system, the excess of air in the presence of less carbon pro- duces a greater percentage of carbon dioxide in the producer gases entering the carburetter, which consumes less fuel per unit of make and produces a larger proportion of sensible heat, which, under the influence of the high pressure, is almost sufficient to heat up the carburetter to the required extent without the use of sec- ondary air. Under these conditions, in which the Elements of Water Gas 105 rate of gasmaking is considerably accelerated, the temperatures of the carburetter and super- heater have not such a wide variation and conse- quently do not require as much heating in each cycle,' and whilst it has yet been necessary to use a small portion of secondary air in the carbu- retter, it is believed that in course of time the secondary air will be dispensed with as the auto- matic and high pressure system develops still further. ADVANTAGES. It is now a well accepted fact that the adop- tion of a shorter cycle will increase the capacity of the set and improve the oil and fuel results, and in order to reduce the cycle to below six or eight minutes, it is necessary to use high pres- sures to obtain the heats in the minimum time and to employ automatic operation to obtain the necessary speed. Briefly, the advantages of automatic operation may be summarized as fol- lows: (1) By accurately timed periods coincident with accurate measurements of air and steam, the operation is placed on a basis at which uni- formity must result. (2) It enables the use of lower grades of fuel containing a higher percentage of ash by reduc- 106 Elements of Water Gas ing the ranges of temperature between the begin- ning and end of the blow, and largely preventing fusion of the ash into clinker. (3) It produces a more constant temperature in the carburetter and superheater, and mini- mizes excess decomposition at the beginning of the run and the production of tar towards the end of the run. (4) It enables fuel to be fed at any part of the run or blow, which allows the volatile mat- ter to be driven off at the most suitable time, according to the nature of the fuel. (5) It keeps the fire at a uniform depth by frequent charging without loss of time, and thereby minimizes the percentage of CO2 in the water gas, and provides a uniform proportion of CO2 in the blast gases. (6) It enables the fire to be kept more healthy at the bottom by preventing fusion of ash into large masses of clinker, and enables the use of a rocking grate which will efficiently remove smaller particles of ash. (7) It allows the water gas to be driven from the machine at the end of the run by enabling the blast valve to be opened a few seconds in advance of the stack valve. Elements of Water Gas 107 (8) It increases the capacity of the set by practically 100 per cent., and thereby reduces the outlay of capital per unit of make. (9) It eliminates the human element and reduces the cost of operation. ( 10 ) It reduces the risk of explosion by avoid- ing the inconsistency of an attendant. In looking over these facts, the experienced engineer or gasmaker will no doubt hesitate in accepting the reliability and efficiency of a mechanical or other contrivance which will sub- stantially bring about such radical changes, and the writer intends, in the following pages, to discuss the relative advantages of apparatus at present brought forward. The first apparatus of which we are aware was designed in England in 1911, but owing to a sudden increase in the rate of oil, the water gas process in that country received a set-back in competition with coal gas, and little interest appears to have been taken in the development of the apparatus for this reason. Other modifi- cations, however, quickly followed, and in the writer's belief the first apparatus successfully operated on a commercial scale was built by the United Gas Improvement Company, Philadel- phia, at a subsidiary plant in Pensacola, Flor- ida, in 1914, and it is now a general belief that 108 Elements of Water Gas an automatic and high pressure system will, in the course of a few years, entirely displace the present system. The reliability of this belief .undoubtedly depends on the reliability and efficiency of the design of apparatus, and the following chapters have been arranged to bring out the fundamental principles governing the respective designs, and enable the reader to firmly grasp the elements on which successful operation depends. CHAPTER VII. MECHANICAL OPERATION. The most reliable means of automatic control is undoubtedly by positive action on the valve mechanism by a substantial application of mechanical means. In this chapter it is intended to outline the generation of blue and carburetted water gas from the automatic standpoint, and to show a combination of apparatus which will serve to illustrate different principles of mechan- ical control from which a variety of modifica- tions could be made. CAM AND CLUTCH MECHANISM. The apparatus referred to in figures 33 to 40 is for the generation of straight or blue water Elements of Water Gas 109 gas, which is theoretically a mixture of hydro- gen and carbon monoxide only and does not contain any hydrocarbons or other illuminating vapors. It is obvious, then, that there is no carburetter or superheater in this apparatus, and as there are no combustible gases required for oil car- bu ration, it is usual to employ a higher blast pressure and reduce the percentage of carbon monoxide as far as possible in the producer gases. Until recent years the producer gases given off in this type of apparatus were dis- charged straight through a chimney in a vertical plane with the generator, it being claimed that the high blast pressures employed produced an excess of oxygen in the generator, and burnt the gases therein direct to carbon dioxide, and con- sequently the gases were of little heating value after leaving the apparatus. It has, however, been repeatedly proven that under the influence of the high blast pressure and comparatively small area of contact surface, the carbon can not be completely burnt in the generator, and also that the gases already converted to carbon dioxide contain a very large amount of sensible heat when passing up the chimney. In the various tests made, it was found that under average conditions from 30 to 40 per cent, of 110 Elements of Water Gas the total heat was lost in the atmosphere, and by arranging a tubular steam boiler in the path of the burning gases, the heat could be used to substantially generate steam at a most conven- ient time. This arrangement also claims to have other advantages, the foremost of which are: (1) It increases the efficiency of the steam boiler by reducing the distance between the boiler and gas generator, and thereby ensures dry steam. (2) It insures the production of the highest steam pressure at the commencement of the run, when the carbon in the generator is at its most active stage for the decomposition of steam. (3) It reduces the relative cost of construc- tion, ground area, and centralizes the plant. (4) It eliminates the necessity of an atten- dant. (5) It reduces the amount of fuel per unit of gas by employing gases that were otherwise lost in the atmosphere. It may be pointed out that blue water gas is not distributed commercially for illuminating or heating, owing to its low calorific value, and such plants are used chiefly for industrial pur- poses. Referring now to the automatic apparatus, Fig. 33 is a general view, showing the principal Elements of Water Gas 111 112 Elements of Water Gas parts, of which 1 is the generator, and 2 is the charging door or stack valve, which is pivoted at 3. A rocking grate is provided at 4, which is actuated by alternately arranged cams on the revolving shafts 8, arranged beneath the ends of the grate bars. The residue from the fuel is directed on the grate bars by side pieces 10, and on passing through the grate is discharged into the ash pit 5, from which it is carried by a worm 6 to the exterior of the machine. The ash pit is kept at a constant level of water to seal the escape of gas and quench the hot ashes. At the top of the generator a steam boiler 11 is provided, and connects with gas generator by funnel 12. The steam boiler is of the tubular type and is heated by the gases from the gen- erator during the blasting period, and by water gas burning in jets from a burner ring 17 during the gasmaking period. The funnel 12 has open- ings at 13 therein for the admission of air to insure the complete combustion of the generator gases. The fuel is stored in the hopper 14, from which it is discharged at intervals by means of a rotating bucket device 15, which discharges a measured quantity into chute 16 and thence through the funnel 12 into generator 1 when the cover 2 is raised at the end of the run. The gas used at the burner ring 17 is supplied through Elements of Water Gas * 113 114 Elements of Water Gas cock 18 and pipe 9, and a slide valve 19 Is adapted to close the funnel 12 when the blast through the generator is cut off, so as to cut off cold air from the boiler during the gasmaking period. The slide 19 has a series of small open- ings to admit just sufficient air for the combus- tion of the water gas. The apparatus is driven from one source of power by means of shafts, gearing and so forth in order that the various operations are accurately timed to take place in their proper sequences. The driving shaft 20 is connected to an engine or dynamo or other source of power controlled by governor mechanism so that the speed remains practically constant. The shaft 20 drives through a worm and worm wheel 21 a second shaft 22, which in turn drives through another worm and worm wheel a shaft 23, which makes one revolution in four minutes, which is the assumed time of each cycle. The shaft 23 drives a shaft 24 running at the same speed, and this in turn drives a shaft 25, which makes one revolution in every three cycles or one in 12 minutes. In Fig. 34 an enlarged view is shown of the valve and operating mechanism which control the flow of air, steam and gas. The source of the air blast is from pipe 26, through a safety Elements of Water Gas 115 valve 27, which serves to keep a constant pres- sure, and through valve 28 and pipe 29 to gen- erator 1. The bottom and top gas outlets are provided at 30 and 31, and are controlled by valves 32 and 33, respectively, which communi- cate by a connecting pipe 34 to branch pipe 35 leading to a relief holder. The steam admission pipe 36 leads from the steam boiler 11 and branches off into pipes 37 and 38 with cocks 39 and 40 therein, the said pipes being carried through the outlet pipes 30 and 31 into the bot- tom and top of generator respectively. The cock 40 is shown in section and turned through a right angle to show its construction. The two cocks 39 and 40 are adapted to be operated by toothed sectors 41 and 42, pivoted at 61 and 62, and connected by links 63 and 64, respectively, to rocking levers 48 and 47, which are pivoted at 50 and 49, respectively. The rocking levers 47 and 48 are also connected by links 43 and 44 to rockers 45 and 46, by which the outlet valves 32 and 33 are operated. The said levers are counterweighted at 51 and 52, and have rollers 53 and 54, which work respectively on cams 55 and 56 on the shaft 25. These cams are shown in detail in Figs. 35, 36 and 38, wherein the cams are separated out and also in plan on the shaft 25. A third cam 57, Fig. 37, having three pro- 116 Elements of Water Gas jections is adapted to work against a roller 58 on one end of a lever 59, which is pivoted at 65 and connected by a link 66 to the arm of the air blast valve 28. The mechanism which raises the cover of the generator is shown more fully in Figs. 39 and 40, in which 67 is a bevel wheel on the shaft 22, Fig. 33, and gears with two bevel wheels 68 and 69, Fig. 40, which are mounted to run loose on the shaft 70 and are held against longitudinal movement by fixed straps or brackets . ( not shown) engaging in grooves 71 and 72 in the bosses of the bevel wheels. The bevel wheels have ratchet clutch faces 73 and 74 formed on them, opposite to which are ratchet clutch mem- bers 75 and 76 revolubly supported on a sliding bracket 77 and working on keyway on the shaft 70. The bracket 77 is adapted to be moved to and fro by means of a toothed sector 78, pivoted at 79 and having a pin 80 at its rear end, which works in a grooved cam 81, driven from the four-minute shaft 23 by means of bevel gear- ing as shown in Fig. 33. The grooved cam makes one revolution in each cycle of operation, and has two principal projections, 82 and 83, which engage with the pin 80 as the cam rotates in the direction of the arrow. A separate mechanism returns the pin 80 to its mid-position in the Elements of Water Gas 117 118 Elements of Water Gas groove, and behind each of the projections 82 and 83 the cam groove is made wide for a space to allow time for the returning mechanism to operate. The returning of the pin and moving back of the bracket and the disengagement of the clutches therein is effected at the opening and closing of the cover of the generator. On the shaft 70 are two pulley drums 84 and 85, over which pass chains 86 and 87, the chain 86 being carried around the pulley 88 to a staple 89 on the cover of the generator, while the chain 87, which runs in the other direction around its drum 85, is connected to a tail piece 90, project- ing rearwardly from the cover 2 and its pivot 3. The cover 2 and the tail piece 90 have projections 91 and 92 respectively upon them, which are adjustable, and which are adapted to knock against and throw over a weighted lever 93, pivoted at 94. This lever is geared through a bevel gear 97 to a shaft 99 carrying a pair of arms 96 and 98, which can strike against a pro- jection 100 on the bracket 77. A stop 95 limits the movements of shaft 99 and its arms 96 and 98. A catch 102 is pivoted on the projection 101 from the support for the member 78, and its forked rear end engages and is moved by the member 78, while its hooked front end coacts with the catch 103 on the cover 2, to hold the Elements of Water Gas 119 120 Elements of Water Gas cover in its raised position. When the toothed sector and lever 78 and the bracket 77 are thrown over into the position for lowering the cover, the catches 102 and 103 are automatically disengaged by the movement imparted to the lever 78. Assuming that the cover 2 be lowered, the pin 80 will be in the long plain portion of the grooved cam 81 on the four-minute shaft and the bracket 77 Avith the clutches thereon will be in the mid-position so that both bevel wheels 68 and 69 are running idle. The projection 82 strikes against the pin 80 when the air blast is turned on, and the bracket 77 is thrown over towards the right, and the clutch 74 and 76 are engaged so that the shaft 70 is turned in one direction of rotation through the bevel wheels 67 and 69. The drum 84 then winds up the chain 86, while the drum 85 pays out the chain 87 and the cover 2 is pulled up until the catches 102 and 103 engage. At the same time the pro- jection 91 on the cover strikes against and throws over the weighted lever 93 and this, in fallijig, operates the fork 98, which throws back the bracket to its mid-position, in which it is held by a spring roller device 104 engages between curved projections 108. The clutches on the bracket are now out of engagement and Elements of Water Gas 121 122 Elements of Water Gas the cover remains in its raised position. At the end of the blasting period the projection 83 strikes against the pin 80 and the lever T8 releases the catch 102 from 103, and simultane- ously the shaft is clutched by the members 73 and 75 to the bevel wheel 68, and is, therefore, turned in the reverse direction while the chain 87 is wound up on the drum 85 and the chain 86 is paid out from the drum 84. The tail piece 90 is therefore pulled up while the cover itself is allowed to fall as its chain 86 is paid out, until it is closed on its seating on the top of the gen- erator. At this time the projection 92 on the tail piece 90 strikes against the weighted lever 93 on the other side thereof, throwing it over in the reverse direction and causing the fork 98 to move over in the other direction to bring the bracket 77 back to its mid-position and to dis- engage again the clutches on the said bracket, in which position it is ready for the next open- ing of the cover when the cam again moves the sector 78. The opening and closing of the cover is accom- panied by the opening and closing of the slide 19, and this is effected by means of the drums 110 around which are passed chains or cables 109. Both of these cables pass around another pul- ley 111, and one cable is attached to the front Elements of Water Gas 123 end of the slide, while the other passes around the flue and around another guide pulley 112 to the rear of the slide. When the pulley 110 rotates the cable 109 is wound up on the said pulley while the other cable is paid out, which results in the movement of the slide in one direc- tion. The reverse movement of the shaft 70 causes the slide to be moved back again to the original position. If the operation of this apparatus is now fol- lowed it is seen that at the same time the cover 2 is raised the air blast is turned on at the valve 28 by means of the cam 57 on the 12-minute shaft 25. As the blasting period continues the steam boiler 11 at the top of the generator is heated by the producer gases, during which time the valve 18 has been nearly closed by the catch 106 so as to cut off the supply of water gas from the boiler. At this period the rotating bucket 15 discharges a definite amount of fuel in the gen- erator, after which the bucket continues its rota- tion and takes in a fresh supply of fuel from the hopper 14 in readiness for the next charging, time when the cover is again raised. At the end of the blasting period the cock 28 is closed as the roller 58 runs down on the smooth part of the cam 57, and simultaneous with this action the cover 2 is lowered by the mechanism pre- 124 Elements of Water Gas viously referred to. The closing of the cover also effects the closing of the slide 19, and the move- ment of the latter turns on the gas at the cock 18 by means of the catches 106 and 107, so that the steam generator continues to be heated. At the same time as the blasting period is being ended the cam 56 causes the steam to be turned on at the cock 39, and the outlet valve 33 to be opened. This puts the generator on the up run for 150 seconds, after which the cock 39 and valve 33 are again closed and the blasting period recom- menced for a period of 90 seconds. During the next period of four minutes the sequence of oper- ation is repeated for the second up run, and in the third period the steam is turned on at the top through cock 40 and the bottom outlet valve 32 opened, which puts the generator on the down run, after which the shaft 25 has gone through one period of rotation and the whole cycle is again repeated. ROTARY VALVES. The most simplest form of automatic opera- tion is undoubtedly that in which a series of rotary valves are employed to control the inlet and outlet ports. The system has been designed especially to effect simplicity of control, and the Elements of Water Gas 125 126 Elements of Water Gas valves are arranged to rotate continuously in a given period from a constant speed shaft, or are provided with mutilated gearing so that the valves are actuated in a rotary direction at the time period desired, after which they remain stationary during the run or blow while the shaft continues to rotate until the gearing again engages at the pre-determined time for the next movement of the valve. In addition to automatic operation the same design of apparatus embodies a new feature in connection with the oil injection, in which a cen- trifugal fan is employed to draw blue water gas from the generator off-take for the purpose of injecting the oil. Briefly, the objects of this are : (1) To atomize the oil and inject in a fine mist. (2) To preheat the oil by direct contact with hot gases before entering the carburetter. (3) To avoid dead holes in the carburetter by insuring a perfect distribution of the oil over the surface of the checkerbrick. ( 4 ) To wipe out the spray after each injection and prevent carbon deposits therein. For the purpose of illustration, the constantly rotating valve system will be described, and Fig. 41 shows a vertical section through part of a carburetted water gas apparatus in which 1 Elements of Water Gas 127 ILL 128 Elements of Water Gas is the generator and 2 the carburetter. The fuel is supplied from the hopper 3 by means of a revolving feed device 4, which delivers a meas- ured charge of fuel into the chamber 5 at fixed intervals, and a valve 6 allows the chamber 5 to communicate with the generator at the desired time to pass the charge therein. The valve 6 is actuated by mutilated gearing from the shaft 7, which rotates once in each cycle. The valve 8 admits air from the pipe 9 to the generator, and valve 10 admits air to the car- buretter by way of inlet 21. The valve 12 con- nects the generator and carburetter, and rotates synchronously with valve 8, so that when air is admitted to the generator the valve 12 allows the producer gases to pass to the carburetter, and a few seconds later the valve 10 operates so that air is passed to the carburetter for the com- bustion of the producer gases. Steam is admitted through the pipe 13 and valve 14, which rotates once in three cycles so that the steam is passed twice to the bottom for the up run and once to the top for the down run through pipes 23 and 22, respectively. The water gas is led from the generator by way of valve 11, which is synchronous with valve 14, and rotates once in three cycles so that the gas leaves the generator twice from the top and once Elements of Water Gas 129 from the bottom in accordance with the admis- sion of steam. The valves 8, 10, 11, 12 are all operated from one shaft 15. Oil is supplied through pipe 18, and 19 is a centrifugal fan which draws gas from pipe 16 and forces it through 20 for injecting the oil. The oil and stack valves are operated from the shaft 7 in a similar way at the same time as the operation of the steam and outlet valves, and will, therefore, need no illustration. The sequence of operation is the same as in the previous apparatus, and briefly it may be stated that the process is controlled by two sets of valves which effect the blasting and gasmak- ing period at the required time, which is con- trolled by the speed of the shafts 7 and 15. The valve 11 is similar in construction to valve 14 and is shown in Fig. 42 through the section lines A, B, C, Fig. 41, where it is seen that the valve has three ports which are placed at an angle of 120 to each other, and open the pipes 13', 14' and 14" in order. In the illustra- tion the port 14" is shown open, while the port 13' will be opened on the next cycle and 14' on the third cycle, when the valve will have made one revolution and the order again commences. The valves 8, 10 and 12 operate together, making one revolution in each cycle, and open the ports 130 Elements of Water Gas during the blasting period and close during the gasmaking period. In this design it is obvious that the operation is of the simplest and most uniform nature and that the plant will require little attention or repair. CHAPTER VIII. ELECTRICALLY CONTROLLED PROCESS. CARBURETTED WATER GAS. In this design of apparatus the principle of operation is that of electrically energizing a member mounted on the valve to be operated in accordance with a pre-determined cycle which is controlled by a contact making and breaking device. The members energized consist of solenoids for the smaller valves, and motors for the larger valves, and by their use the automatic means can be applied to any existing design of appa- ratus or valve mechanism and ensure a substan- tial and efficient operation in a speedy or retarded manner as desired. It is obvious that the scope of electrical control is very broad and could be applied to various combinations of mechanism with- out departing from the principles hereafter Elements of Water Gas 131 described. However, a description of all the means of application is impossible in a work of this kind, and for the purpose of illustration the most simplest design will be referred to. In Fig. 43 is shown a form of apparatus ol the usual standard type with regards to the generator, carburetter, superheater, and wash- box, and is provided with the usual inlet and off-take ports. The charging of the fuel into generator 1 is effected from the hopper 2 by means of a pair of rotating drums 3 and 4, the upper one of which has a pocket which receives fuel from the hopper each time the pocket comes in the position shown. The drum 4 has also a similar pocket, which is adapted to be turned into a position to receive the fuel from the drum 3 when the latter is inverted, and on further rotation the drum 4 causes the fuel to be dis- charged into the generator at any period of the run or blow which is found to be the most appro- priate, according to the nature of fuel and work- ing conditions. The shafts of the two drums are connected together by chain gearing and rotate in a given period, and since the drum 4 is adapted to discharge into the generator when the drum 3 is being charged from the hopper, the two drums prevent the escape of any gas when charg- ing is taking place, whilst at the same time the 132 Elements of Water Gas Elements of Water Gas 133 heat of the machine is kept from the upper drum and storage hopper and thereby avoids all risk of the fuel being volatilized before entering the generator. The lower shaft 6 receives its motion from the shaft 5, which in turn receives its motion from an electric motor driven through gearing, the last element of which is a worm wheel 7 on the shaft 5, which also is adapted to give motion to shafts 8 and 9, on which are mounted drums enclosed in a casing, which serve to control the time of operation according to the desired cycle. The carburetter and fixing chamber 10 and 11 are arranged slightly different from the usual manner, in that the two chambers are enclosed within one shell, the purpose of which is to avoid unnecessary loss of heat, and the admission of air to these chambers is controlled by a valve actuated by solenoid 13. The solenoids 12, 13 and 14 each comprise a coil 18, partially enclosed in an iron casing 19, fixed in a certain position so that the coil acts when energized upon armatures 20, carried upon frames 21, which are of brass or other non-mag- netic material, and is pivoted upon the axis 22. The frames 21 also carries an arm 23, Fig. 44, which is adapted to co-operate with a pair of stationary contacts 24 and 25. 134 Elements of Water Gas f 6J 6263 Elements of Water Gas 135 One terminal of each of the coils 18 is perma- nently connected with the negative main 26 by a wire 27, and the contact plates 24 and 25 are connected by wires 28 and 29 with contact mem- bers, which, through the intermediary of the con- trolling drums, are adapted to be put in con- nection with the positive main 30 for energizing the solenoids. Assuming, then, that the wire connected with the contact plate 25 of the sole- noid 12 is put into communication with the posi- tive main, the coil 18 is energized by way of plate 25 and arm 23, and the solenoid attracts the armature and moves it until it takes up a central position relative to the iron casing 19. As it reaches this point the arm 23 moves off the contact plate 25 so that the connection with the positive main is broken, and the solenoid thereby becomes de-energized, at which period the inertia of the armature 20 causes it to swing past its central position and enables it to complete the end of its movement by gravity. In the com- pletion of this movement, the arm 23 is brought in contact with plate 24, so that the circuit is ready for the next energizing of the solenoid for bringing the armature back through the reverse movement to the position shown in Fig. 43. The solenoids 13 and 14 operate in a similar way, but in 14 an additional device is provided, the 136 Elements of Water Gas object of which is to reduce the disadvantageous effects of self-induction of the coil 18. This device consists essentially of a resistance 31, Fig. 45, which is connected with wire 27 and also with terminal 32, and by such connection it is obvious that on the movement of the arma- ture 20 the arm 23 breaks contact with plate 25 and makes contact with plate 24 and closes the circuit through the wire 28, the connection to terminal 32 and resistance 31, instead of break- ing it permanently as in the previous example. In order to produce the reverse movement of the solenoid with this additional device, it is neces- sary to connect the terminal 32 with the wire 29 instead of 28, and to change the connection of the positive main 30 to the wire 28 instead of wire 29 as indicated by dotted lines. The oil and stack valves on the carburetter and superheater, respectively, are actuated from an electric motor 33, which has permanently Elements of Water Gas 137 connected with its shaft a centrifugal fan 34, which draws water gas through the pipe 35 from the generator off-take 36, and forces the gas through the injector 37 by which it draws oil from pipe 38 and sprays it into the carburetter in a very fine mist. The motor 33 also has on Its shaft an electro-magnetic clutch 39, Fig. 44, by which the shaft is adapted to be put into opera- tive connection with a pinion 40 driving a gear wheel 41 on the shaft of which is a worm 42 driving a worm wheel 43, on the shaft 44, which actuates the oil valve 45 and stack valve 46. The shaft 44 also carries a controlling drum 47, which is referred to later. In the operation of the motor 33 and its asso- ciated parts, one terminal of the motor, and one terminal of the coil of the clutch 39 are perma- Elements of Water Gas SSSS^SSSSSSSSS^^ ^^^^^^ SSS$5S*S8SSsS5S^ ^^:^$5S^^^^^ vS^^Ki^^^^ 9 nently connected by the wire 48 with the nega- tive main 26. The connections to the positive main are made through the controlling drum 47 and the contact members shown in the lower Elements of Water Gas 139 part of Fig. 44 coacting with the main con- trolling drums 8 and 9, Fig. 43. On opposite sides of drum 47 are mounted a series of curved contact plates insulated from each other, the end views of which are shown in the upper and lower parts of Fig. 46. From the side view of the drum, shown in Fig. 44, it is seen that the plates are mounted on helical sur- faces, so that as they rotate, they gradually press the brushes 49 and 50 back, and then permit them to snap on the next contact plate when the end of the first contact plate is reached, which action enables the circuit to be quickly broken. The left-hand end of the drum 47 carries four contact plates connected together in pairs, as seen in the upper part of Fig. 46, and the right- hand end of the drum has two contact plates, as seen in the lower part of the figure. From each end of the drum two connections pass to the contacts of the main controlling drum, which is adapted to put them at appropriate periods into connection with the positive main 30. When the drum 47 is in the position shown in Fig. 46, and the wires 52 and 54 are put in communica- tion with the positive main 30, the motor 33 com- mences to rotate and at the same time the coil of the clutch 39 is energized, so that, in addition to driving the fan 34, the motor also rotates the 140 Elements of Water Gas shaft 44 and actuates the valves 45 and 46, open- ing the oil supply and closing the stack valve. When these valves have moved to the required extent, the next contact plate comes under the brush 49 so that the circuit of the coil of the clutch is broken, which causes the shaft 44 to come to rest, while the motor continues to rotate and drive the fan 34. The stoppage of the motor, accompanied by the second operation of the valves 45 and 46 at the end of the run, is brought about by connecting the wire 51 with the posi- tive main 30, and again energizing the clutch 39, and causing the shaft to rotate through another quarter of a revolution, at which the circuit of the coil of the clutch, and the circuit of the motor is broken at the brushes 49 and 50, respectively. In re-starting the motor and energizing the clutch at the end of the blasting period, the wires 53 and 52 are put in communication with wire 30. The movement of the valves 55 and 56, Fig. 43, for the steam supply to the generator is effected by the rocking of the armature 20 of the solenoid 12, through a lever 57, actuating a pair of con- necting rods 58, which rotate the shaft 59 through pawls acting on a ratchet wheel. On this shaft there is mounted a disc 60, having pins projecting from the two sides so as to act Elements of Water Gas 141 upon radial arms on the spindle of the valves 55 and 56. The pins acting on valve 55 project from the rear of the plate, whilst those acting on valve 56 project on the front of the plate, and their disposition is such so as to obtain the cor- rect timing of the opening and closing of the valves, according to the desired cycle. In the illustration it is assumed that the cycle of oper- ation is two up runs and one down run, and four pins are provided at the front of the plate so as to open and close the valve 56 twice in succes- sion, whilst two pins are arranged on the rear of the plate so as to come into action after the four pins referred to, and thereby open and close the valve 55 once for each revolution of the plate. By this means steam is caused to be admitted twice to the lower part of the generator through pipe 88, and once to the top part through pipe 87 in each cycle of three runs. The main controlling drums 8 and 9 are approximately cylindrical in form, and consist of a series of plates, Fig. 47, which are adapted to strike against the contact fingers indicated by the circles in the lower part of the figure. The plates are all connected together so that a posi- tive current flows through them all, and the sur- face of the plates are partly of metal and partly of insulating material, according to the work of 142 . Elements of Water Gas each, so that when the metal portion strikes the contact finger the current is transmitted through the finger to the valve mechanism to be operated. The surface of the drum is not perfectly cylin- drical but has steps form on it in front on the leading edge of each part of the metal portion, so that the spring contact members snap quickly over from the raised part of insulating material on to the next contact plate, and thereby estab- lish the circuit rapidly, and bring about a cor- responding rapid action on the valve mechanism with which the respective circuits are associated. The form of the drum is more clearly shown by the section in Fig. 48, where contact plates are shown located on the stepped body of insulating material, and the direction of the drum is indi- cated by the arrow. It should here be noted that the breaking ot the circuit does not occur at the drum, but at contact members carried by movable parts of the apparatus, so that it is not very material at which point the contact plates end, but they Elements of Water Gas 143 have, however, been shown as continued as far as possible over the surface of the drum in the direction of the movement, so that if the mem- bers which have control should be accidentally put back in a wrong position, the circuits will be closed and the valve mechanism will move to the position with which they are due to occupy at definite parts of the cycle. If the sequence of operation is now followed it will be obvious that the proceeding is as fol- lows: Commencing at the beginning of the cycle, the contact 61, Fig. 47, is put into com- munication with the positive main, and the con- tact 68 has been previously connected with the positive main and remain so connected at the time. This causes the shaft 44 to be rotated so as to close the oil valve and open the stack valve, and simultaneous with this action, the contact 62 is connected with the positive main which ener- gizes the solenoid 12 and causes air to be passed into the generator through the pipe 90 by the rocking of lever 57, which actuates the valve. At the same time the movement of the lever imparts an angular displacement of the disc 60, which causes the steam supply to be cut off at one or the other of the valves 55 or 56, according to the previous run. The producer gases pass 144 Elements of Water Gas off by way of pipe 16, valve 15, and pipe 36 to the carburetter 10 and superheater 11, and finally through valve 46 and chimney 92. About 10 seconds after the contact 62 has been put into connection with the positive main, the contact 63 is thus connected, and accordingly the solenoid 13 is energized, which opens the valve on pipe 91 and passes air into the carburetter and super- heater, if desired. The blasting period having been thus estab- lished continues for 90 seconds, when contacts 64 and 65 are put into communication with the positive main, which again energizes solenoids 13 and 12 and causes them to cut off the air supplies to the apparatus, and simultaneously open the steam supply. A few seconds after this action, the contacts 66 and 67 are put into com- munication with the positive main, by which the motor is started, and the clutch 39 energized, so that the shaft 44 is caused to turn and close the stack valve and open the oil valve. The clutch is then de-energized by the drum 47, pre- viously referred to, while the motor continues to run and drive the fan 34 for injecting the oil into the carburetter. The condition has now been established for a run of gas, and this con- tinues for 150 seconds until the fuel needs reviv- ing by the air blast. Elements of Water Gas 145 The second run constitutes another up run and the proceeding is exactly the same as just described. When the drum has passed through 91/2 minutes of its rotation, which is equivalent to the two runs and the third air blast, the con- tact 71 is put into communication with main 30 and the contacts 69 and 70 are connected together which produces the energizing of the solenoid 14 and the movement of the valve mem- ber 15 from the position shown in Fig. 43 to the position in which the pipe 16 is cut off and the pipe 17 opened. This operation synchronizes with the closing of the air valve and opening of the steam valve 55, so that the steam is passed into the top of the generator and the gas passed off at the bottom by way of pipe 17, which con- stitutes the down run. This condition continues for 150 seconds, when contact 69 is connected with the positive main, and the contacts 70 and 71 are connected together, by which the solenoid 14 is again energized and the valve 15 moved back to the position shown in Fig. 43 when the cycle again commences for another up run. In large installations where considerable fuel is used, the drum 37 is geared with the shaft 5 at three to one, so that fuel is charged into the generator at each cycle while the drum makes 146 Elements of Water Gas one revolution in every three cycles in order to bring about the up and down runs in the pro- portion of two to one. BLUB WATER GAS. The automatic operation of blue water gas apparatus by electrical means is practically the same as in the previous example, and the pro- ceeding is only slightly different in accordance with the different construction and purpose of the apparatus. Keferring to Fig. 49, the part 96 is a tubular steam boiler, and is connected with the gas gen- erator with a flue section, which has a series of apertures for the admission of air for completing the combustion of the producer gases. This sec- tion is also provided with a gas burner ring con- trolled by the cock 83, which gives heat to the boiler during the gasmaking period, and is adapted to be almost turned off during the blast- ing period when the top of the generator is opened at 80 for the flow of producer gases. The rod of the bell 80 is also connected by links (not shown) to the apertures in the flue section, so that these are partially closed when the generator is closed and opened when the bell is lowered. By this means the air supply is Elements of Water Gas 147 148 Elements of Water Gas reduced to the boiler during the run of gas, only sufficient being admitted to burn the gas at the burner ring. The fuel is discharged from the bucket 3 and to the bell 80 and then to the generator, and the bell is suspended by means of a rod and chain on a segment of one end of a lever 81, which is pivoted at 97. The provision of a rod as one of the connecting members insures that the bell can be forced down by the pressure of one end of the segment on the rod if it should be held up by the pressure of gas or otherwise. The lever 81 is connected by a link with a crank on the spin- dle of the cock 83, so that when the bell is low- ered the cock is partially closed, and when the bell is raised the cock is opened. The lever 81 is actuated through solenoid 84 through the intermediary of a pin on a crank 85 working in a slot in the lever, and in the two positions of rest the line of pressure acts along the line of crank, and thereby exerts no turning effect on the crank so that the weight of the fuel can not force the bell down until the solenoid is energized. An additional valve 98 is provided on the gas off-take 36, the purpose of which is to cut off the gas holder from the machine when the bell is lowered, and thereby prevent gas from return- Elements of Water Gag 149 99 -23 29 12 28- nrr 1001016Z66 lOZta 69 70-71 150 Elements of Water Gas ing. It will be obvious that this valve has the same purpose as the water seal in carburetted water gas apparatus, but inasmuch as blue water gas is essentially a mixture of hydrogen and carbon monoxide, there is no tarry matter to be removed, and in certain cases the seal could be eliminated with advantages or substituted with a specially designed washer-scrubber. The valve 98 is actuated by solenoid 99, which is similar to solenoid 84 and operates in con- junction with it. The solenoid 84 is connected with contact 100 and 101, and solenoid 99 with contacts 102 and 103, Fig. 50. In the operation of this plant, a controlling drum is employed, the principle of which is the same as in the previous example, but is slightly different in regard to time and action in accord- ance with the different conditions. As pre- viously stated, a high pressure blast is usually employed in blue water gas apparatus, and the blasting period is reduced to one minute whilst the runs of gas are approximately three minutes, which makes the cycle at four minutes, or one complete cycle of three runs at 12 minutes. The controlling drum, which is shown diagramati- cally in Fig. 51, is driven on the same shaft as the charging apparatus, and makes one revolu- tion to three of the latter, and, as seen from the Elements of Water Gas 151 diagram, the solenoids all come into operation practically at the same time, by which it is pos- sible to simplify the connection by allowing solenoids 12, 84 and 99 to be operated from the same contact members. The diagram, however, 62 -O at-o is prepared on the assumption that it is desirable for electrical consideration to maintain the cir- cuits independent so that they are not connected together except when the contact members are on the metal part of the drum. In view of the sequence of operation being described in the carburetted water gas appa- ratus, it is believed that a detail description is not necessary in the blue gas apparatus, inas- much as the action of the controlling drums on the solenoids and valves is practically the same. Briefly, the process is that of heating the bed of fuel to incandescence by a powerful air blast for a period of one minute, during which time the steam boiler is being heated by the complete combustion of the producer gases, after which the air blast is cut off and steam admitted instead for a period of three minutes, during 152 Elements of Water Gas which time gas is generated and carried off to the holder, and the steam boiler is heated by water gas from a burner ring as herebefore described. It may here be pointed out that pivotal parts connected with the valves and solenoids are pro- vided with counterbalance weights which serve to equalize the load during each of the two strokes, and the valves have also the lever attach- ment, each of which are connected by link mechanism to a lever at a centralized point so that in the case of an electrical breakdown the valves can be operated by hand, and by centraliz- ing the operation one or more valves can be oper- ated simultaneously and thereby effect a rapid changing action on the apparatus. CHAPTER IX. HYDRAULIC AND AIR SYSTEMS. HYDRAULIC CONTROL. A recently adopted system 'of automatic con- trol is that of acting on the valve mechanism by hydraulic power by means of a cam or tappet arrangement which controls the source of power. The object of this system is to provide means by which the power can be turned on in a rapid Elements of Water Gas 153 154 Elements of Water Gas manner by the movement of a comparatively small valve, and allow the water pressure in turn to act upon cylinders and pistons which are connected through link motion to the valve mechanism on the gasmaking apparatus. The apparatus valves associated with this system are usually of the slide variety where the pistons need to move in a vertical plane, and in large valves which require to be moved through a considerable distance in a limited time, a series of hydraulical valves are provided, of which there are one for each slide valve to be operated. The hydraulic valves are in turn con- trolled by a series of pilot valves 10, Fig. 52, of which 11 and 12 are the inlet and outlet con- nections. The stem of these valves project from the casing at each end at 13 and 14 to the tappet arms, and the valve body communicates with a double acting piston and cylinder 15 by way of 16 and 17. The pistons of each of the ele- ments 15 are provided with hand lever 18, so that the apparatus can be operated by hand if desired. The valves 19 are connected through stem 20 with the pistons of the elements 15, and by their combination with the valves 10 the pistons and cylinders co-operate in such a way that a slight movement of the pilot valves 10 opens up large fluid ways to the valves 19 and Elements of Water Gas 155 156 Elements of Water Gas causes the slide valve on the gasmaking appa- ratus to move quickly through a comparatively long distance. The inlet and outlet connections from valves 19 are provided at 21 and 22, Fig. 53, and 23 and 24 are connected from the said valves to the apparatus valves pistons and cylinders. The valves 19 are shown more fully in Fig. 53, and are enclosed in a suitable casing, which is con- nected with or carried by a frame 25 that sup- ports the pilot valve pistons and cylinders, and also other parts as hereafter described. The inlet 21 is common to all these valves and also the outlet 22, and the casing of the valves are connected at 26 and 27 by means of suitable openings which constitute inlet and exhaust ports. The opening 27 at the left-hand end is connected by a port 28, which communicates with the outlet 22. A pair of interconnected cam shafts are pro- vided at 29 and 30, Figs. 52 and 54, and are geared together by wheels 31, 32 and 33, and move in the same direction from a source of power which is usually an electric motor. The said shafts are mounted in brackets 36 on the frames 25, and each shaft is provided with tap- pet or other projecting devices 37 and 38, of which there is a pair for each pilot valve. The Elements of Water Gas 157 158 Elements of Water Gas tappets of each pair operate upon one of a pair of spring retracted followers or tappet arms 39 and 40, which in turn operates respectively upon opposite faces of a head 41 on the pilot valve spindle. At the other ends of these arms a roller 42 is provided, which has a knife edge 43, and ordinarily runs on the rim of the cam, keep- ing the knife edge clear of it. When the tappet arm, however, is about to drop into the lower part of the cam, the roller first runs into a groove 44 in the cam, and permits the knife edge to ride on the wear plate 45, and finally allows it to drop into the low part 46. This results in the tappet arm being quickly moved for the sub- sequent operation of the apparatus valves. It should here be noted that the function of the two shafts with their respective cams and tap- pets is to operate the pilot valves in opposite directions, and the position of the tappets is such that at the end of the movement the pilot valves are left in a position relative to the opera- tion of the gasmaking apparatus valves. The regulation of the shafts and their cams can be made by disengaging the wheel 32 and turning the shaft 30 by applying a crank to the square end 47, and meshing the wheel 32 to the desired position. The shafts 29 and 30 drive through a pair of gear wheels 48, two concentric dials 49 Elements of Water Gas 159 and 50, which serve to indicate the relative angular position of the said shafts. A shaft 51, which is revolvably supported in the frame 25, is provided with tappet arms 52, Fig. 52, so that when the shaft 51 is turned from its normal position, its arms 52 push the pilot valves into a position which correspond to one of rest and safety of the valves on the gasmaking apparatus. On the shaft 51 there is also an arm 53, which is subjected to the pull of a spring 54, and also the pull of an electro-magnet 55. When the circuit 56 is connected with a live wire, the spring and electro-magnet balance each other, and the parts associated therewith are in the position shown, but on the failure of current in the circuit the power of the spring predomi- nates and turns the arm 53 into a position for bringing the arm 52 into action on the pilot valves. A circuit breaker 57 is provided in the live circuit, and is connected to a weighted arm 58 that is held up by a diaphragm 59, which is exposed to the fluid pressure system, which oper- ates on the various apparatus valves. By this means a safety device is obtained, in that if the power in the fluid system fails, the circuit is interrupted and the safety mechanism controlled by the electro-magnet comes into operation. An oxtra precaution is also provided in the form of 160 Elements of Water Gas a pair of centrally pivoted dogs 60 and 61, Fig. 53, which are normally held in their position (dotted lines) by springs, in such a way that their inner ends 62 and 63 block the line of travel of one of the handles 18, which is linked to the stack valve and prevents the valve from being closed and thereby leaves the apparatus in a safe position. The handles 18 adjacent to the stack valve handle constitute the generator and carburetter air blast, and operate the tail of the dogs 64 and 65 when pulled down and turn the dogs into the position shown by full lines in which their inner ends does not block the stack valve handle. In this arrangement it is obvious that the stack valve handle can not be pulled down until the generator and carburetter blasts have been pulled down, and when all the valves are in the up position, it is evident that the air blast must be cut off first before the stack valve can be closed. The operation of the process according to this system may be briefly described as follows : The speed of the shafts 29 and 30 is adjusted so that each makes one revolution in each cycle of opera- tion of the gasmaking apparatus. The cams 38 on the shaft 30 are set in respect to each other that they cause the mechanism with which they coact to move the valves at the end of the run Elements of Water Gas 161 and commencement of the blast, and the cams 37 on the shaft 29 are set in their respective order to move the valves at the end of the blast and commencement of the run. This condition continues while the mechan- ism is in working order, and in the event of a failing of power on the shafts, the safety device comes into operation and leaves the apparatus in a safe position, whereafter the machine can be operated manually by levers 18 until the auto- matic mechanism is repaired. AIR CONTROL. A modification of the latter apparatus is that in which hydraulic pistons are employed to actuate the apparatus valves, while the control is affected by means of air pressures acting on the fluids in the hydraulic cylinders. The air control is a development of the former apparatus, and its object is to produce greater activity in turning on or off the source of power and thereby speed up the movement of valves passing through a long distance of travel, as in the case of large gate valves which are usually employed in connection with these systems. The air controlling valves, Fig. 55, are actuated from a constant speed shaft, which car- 162 Elements of Water Gas ries a series of cams, of which there is one for each valve to be operated. Each of the valves on the gasmaking apparatus are self-closing, with the exception of the stack valve, in the sense that the operating levers 1, Fig. 56, are provided with weights 2, which force down the rods 3 when the upward pressure is released. Attached to each lever there is fluid cylinder and piston 4 connected by a pipe 5 to a reservoir 6. These pipes have interposed in them a valve 7, the stem of which is connected with levers 8, pivoted at 9, and have their ends 10 in range of the cams. When, the valves 7 are in the position shown in Fig. 55, they correspond to the position of the lever 8, shown in Fig. 56, so that the pipe 11' is in communication by means of port 12 with the exhaust pipe 13, but when the end of the Elements of Water Gas 163 164 Elements of Water Gas lever is raised the pipe 11 is put into communi- cation with 11', which leads to the reservoir 6, which in turn communicates with the cylinder and pistons 4 of the apparatus valves. The method of control of one valve is similar in all the valves associated with the apparatus, and the description may, therefore, be confined to one. When the end 14 of the cam collides with the end 10 of the lever 8, it opens the valve 7, which causes a pressure of air to flow from a compression tank by way of 11 and 11', and into reservoir 6, where it acts on the fluid and causes it to flow through the check valve 15 and lift the piston 4, connected to the lever 1, which actuates the apparatus valves through rod 3. At the end of the given period the action of the cam on the point 10 ceases, and the spring 16 pulls down the lever and breaks the com- munication of valve 7 with pipe 11', and allows the air in reservoir 6 to escape through pipe 13. This action causes the weight 2 to move the pis- ton downwards and close the gasmaking appa- ratus valves at the desired time as predetermined by the length of the cam, which is adjustable at each of the ends 14 and 17 by means of a slot and pin connection. The shaft 18 controls the operation on a cycle, according to its speed of rotation, and is driven Elements of Water Gas 165 166 Elements of Water Gas by a clockwork arrangement. This consists of a gear 19, Figs. 56 and 57, connected with the clockwork, and a weighted lever 20, which is Elements of Water Gas 167 adapted when released to arrest the pendulum 21 out of the plumb and stop the clockwork, and also when restrained by the cord, it is adapted to free the pendulum and consequently let it swing and oscillate. A governor is also provided to keep the shaft at normal speed, and consists of pivotal arms 23, Fig. 58, which at normal speed clears the projections 24, as illustrated by dotted lines, but which, at an increase in speed, strikes the projection and arrests the clockwork. The arms constituting the governor are adjusta- ble by winding the shaft 25 of the clockwork. CHAPTER X. CONSTRUCTION DEVELOPMENTS. VALVE MECHANISM. In the previous descriptions of automatic operation it is obvious that the apparatus illus- trated constitute three distinct principles of con- trol, from which a variety of modifications may arise, to be especially adaptable to any one par- ticular design of apparatus valves. In the elec- trical and mechanical arrangements, the valves used are of the rotary and angle types, inasmuch as these valves move through the smallest dis- tance of travel in opening and closing, and 168 Elements of Water Gas thereby effect a most rapid opening and closing of the connections associated therewith, whilst at the same time the valves are equally bal- anced for movement in either direction. In the hydraulic and air system of control it is evident that the action is especially adaptable to valves of the slide variety, in view of the fact that the primary object is to effect a rapid action on valves passing through a long distance of travel by the movement of an air or hydraulic valve, which is comparatively smaller, and thereby only need move through a short distance in order to apply the power to the apparatus valves. It has been claimed, however, that the air and hydraulic systems are more adaptable to machines already in operation by manual labor, inasmuch as the slide valve is almost universally adopted in these plants, and that by applying the automatic operation to apparatus without the substitution of a different type of valve, a less outlay of capital will be needed. Whilst this claim may carry some weight with those unskilled in the art, it is clear to the technical man that the efficiency of the mechanical or electrical operation on the valves illustrated is much greater than the hydraulic or air systems on the slide valve, and would more than compen- sate the outlay of capital in substituting types Elements of Water Gas 169 of valves especially suitable to automatic opera- tion. It is clear, however, that the mechanical means is equally adaptable to valves of the slide variety, in view of the fact that the power can be made to act in either a vertical or horizontal plane, whilst positive action is assured at all times. A convenient and substantial mechanical arrangement applicable to valves of the slide variety would be to provide a shaft running at constant speed in accordance with the cycle, and connected to the rack of the slide valve by means of gear wheels, which are put into communica- tion at the required time by sliding pinions actu- ated by a lever or grooved cam. In this way a rapid action would be obtained on the valves, and such could be opened at any desired -speed, according to the speed of the shaft and size of the pinions. In the writer's opinion, however, the slide valve is not to be recommended for automatic operation, in view of the unequal weight in its up and down movement, and com- paratively long distance of travel, and it is believed that the valves illustrated in the mechanical and electrical methods possess a much greater efficiency. 170 Elements of Water Gas AUTOMATIC CLINKERING. It has been shown that the importance of keep- ing the fire in a healthy condition comes second to none in the economical operation of water gas apparatus, and various attempts have been made to remove the ashes and clinker automatically. It is well known that in the direct fired furnaces as used in the generation of steam, there are many designs of moving grates which have met with a fair degree of success, but in water gas apparatus, however, the conditions are more dif- ficult, in view of the higher and variable tem- peratures brought about by the alternation of the run and blow, and also amount of fuel used per square foot of grate area per unit of time. In the methods that have been tried it is found Jhat the larger masses of clinker could not be successfully removed, whilst the movement of the smaller ash was accompanied by the removal of a comparatively large amount of small fuel, and was, therefore, not economical. It was also found that the grate bars suffer rapid deteriora- tion by the heat brought down upon them during the down run. A modification of the rocking grate which may claim to have a fair degree of efficiency is that which is only moved occasionally at the most Elements of Water Gas 171 suitable time. In this grate the bars are of ordi- nary construction, and are adapted to be moved at intervals of about 30 minutes for one or two oscillations only. The period of oscillation takes place immediately after the down run, and breaks up the thin layer of clinker so that it falls through the grate bars into a pit from which it is carried away by a worm discharge working in a water seal. The object of moving the bars after the down run is that the clinker formed during the next three blasting periods provide a protection for the bars when they are subjected to the heat under the pressure of the down run, and in small installations where the clinker formed would not be sufficient to form a layer the design of the bars are such that they turn over at each oscillation period and the surface previously exposed to the fire is exposed to the cooling action of the steam during the next period of three cycles, so that the same surface of the bars are only exposed to the influence of the down run but once without being cooled by the steam which enters Inmeath the grate during the up run. From the previous description of automatic operation it will be clear that the bars can be actuated at the required time in a variety of ways, and this will need no further description. 172 Elements of Water Gas In view of the fact, however, that the movement of the bars is only required at certain times, it may, in certain cases, be more economical to move them manually by means of a lever which may be connected to a source of power, or by a wheel suitably geared down to the actuating shaft. CARBURETTING ZONE. In injecting the oil into the carburetter it is found that the top courses of brick suffer more rapid deterioration than the rest of the appa- ratus, which is partly due to the force of the injection, and partly to the greater variation of temperature at the beginning and end of the run. During the air blasting period these top courses of brick receive the greater percentage of sen- sible heat from the generator, and are conse- quently heated to a higher degree during the air blast than the rest of the machine. When the oil is injected these bricks are subjected to the pressure of the injection and are splintered at the result. It is to be noted, however, that the temperature of the carburetter needs to be higher at this point than the rest of the machine, in order to supply an extra heat equivalent to the "latent heat of vaporization" of the oil, and the object of the carburetting zone is to provide Elements of Water Gas 173 means by which the top of the carburetter can be raised to a temperature which is compara- tively higher than the rest of the fixing appa- ratus, and thereby supply sufficient heat for the vaporization of the oil at one centralized point and enable the temperature of the fixing cham- ber to remain more constant and consequently lengthen the life of the brickwork contained therein. Assuming that the pyrometer at the bottom of the carburetter records 1,400 F., it may generally be taken that the top of the car- buretter is about 100 F. higher while the top of the superheater is 100 F. lower, the gradual fall in temperature being due to the vaporization and breaking up of the oil as it passes through the apparatus. If, then, the vaporization of the oil could be centralized, a portion of the car- buretter and superheater would remain at a more constant temperature throughout, whilst the centralized point or carburetting zone could be filled with special constructed brickwork adapted to withstand the higher temperature. In order to raise this zone to a temperature which is comparatively higher than the rest of the apparatus, it is suggested that the walls of the zone be built oval so that the blast gases are given a circular motion, and instead of passing direct through the apparatus, they repeatedly 174 Elements of Water Gas react on the brickwork contained in the zone and thereby give up a greater percentage of heat within it. If the oil is then injected in a fine mist by means of a fan or otherwise, and led into the zone in a circular manner, the latent heat of vaporization of the oil will be counter- acted under the higher temperature and repeated contact, and the rest of the apparatus will remain at a more constant temperature and break up the oil vapor to the required degree, instead of subjecting the oil vapors to the vari- able temperature and evitably producing excess decomposition to a certain amount of the lighter hydrocarbons. i SELF SEALING CAP. At the stack valve or cap it is usual to pro- vide a pilot light to burn up gases which are liable to leak through the valve, as these gases, when passed into the atmosphere unburnt, pro- duce complaints from neighboring residents. It is well known that this valve frequently becomes coated with lampblack and tar, and occasionally during working periods the waste of gas is com- paratively large. It is obvious that this con- dition could be easily and inexpensively rem- edied by providing a cap with an outer rim Elements of Water Gas 175 adapted to dip into a water seal when the cap is closed. The escape of gas could then be passed off through a pipe in the seal basin to the wash box, or to a small holder of about 10 cubic feet capacity, where it provides a good mixture for an indicating photometer or for analytical pur- poses. The seal and rim could be provided with an opening extending to within one inch of the cap seating for the usual pilot light to ignite unburnt gases during the blasting period. . NOTES ON CONSTRUCTION. The engineer who is contemplating the erec- tion of water gas apparatus will find it to advantage to compute the cost of constructional developments associated with the apparatus before deciding upon a contractor's estimate. Of course, local rates can usually be obtained for excavation, concrete work, bricklaying and car- pentry, but in the face of this the essential data for obtaining such prices will generally be of service. EXCAVATION. It will be in order to first consider the item of excavation of a trench, say, five feet deep, which included the leveling of the bottom and 176 Elements of Water Gas fixing or removing planking. Assuming that the ground is of ordinary description, the amount of soil capable of being thrown out per man per day of nine hours may be taken at nine cubic yards, at a cost of approximately $1.50, or 16.66 cents per cubic yard, to which may be added one- tenth for the laying and removing of planks, which makes the cost at about 18.30 cents per cubic yard, and it will also be well to provide one-tenth for supervision, making the total cost at approximately 20 cents. CONCRETE. The concrete floor of the generator house should then be considered, and a mixture of one part of cement to five parts of a mixture of gravel and sand will, under ordinary conditions, be found suitable. In view of the fact that the sand and cement diminishes in volume when mixed with water, the approximate quantities per cubic yard may be taken as : .75 cubic yards of gravel. .50 " " sand. .25 " " " cement. 25 gallons of water. The cost of these materials varies consider- ably, according to the location, and on the aver- Elements of Water Gas 177 age may be taken at $2.10, to which 20 cents per cubic yard should be allowed for laying and 10 per cent, for superintendence, making the total cost at approximately $2.50 per cubic yard. Assuming that the floor is to be laid at a thick- ness of nine inches, one cubic yard will be equal to four square yards of floor surface, which makes the cost per square yard at $0.625. BRICKWORK. In computing the cost of brickwork it is well to first consider the lime mortar, which may be computed of one part lime to three parts of sand, and 40 gallons of water per cubic yard. The cost of these materials also vary greatly accord- ing to location, and may be taken at $3.25 per cubic yard, with an addition of 45 cents for labor or $3.70 per cubic yard. Assuming the brickwork to be one and one-half bricks in thick- ness, the material desired per rod will be approx- imately : 4,500 bricks at $10 per 1,000 $45.00 500 gallons of water 10 Bricklayers' time (four days at $5) 20.00 Laborers' time (four days at $1.50) 6.00 Scaffolding 1.50 178 Elements of Water Gas Two cubic yards of mortar 7.40 $80.00 Ten per cent, superintendence 8.00 $88.00 This does not include pointing the building, and if same is desired a 1 per cent, allowance should be made. COLUMNS AND GIRDERS. On the roof and floor of a generator house it is necessary to eliminate wood of any descrip- tion and provide steel girders and columns, as the temperature of the room and liability of explosion would be an incentive to fire in the presence of timber. The main girders are usually about eight inches, and are built in the wall, and extend the length and breadth of the build- ing with supporting columns or angle irons at about every ten feet. It is necessary to provide for four-inch girders which are bolted at right angles to the main girders at about every three or four feet to receive the floor plates, which are usually of cast iron. The roofing is provided by extending six-inch girders over the breadth of the building at dis- Elements of Water Gas 179 tances of about 15 feet, upon which are placed smaller girders at distances which vary accord- ing to the roofing material. This may be of tiles, slates, or corrugated iron, and the cost will vary accordingly. With this data the amount of girder and roofing material can be computed, and this in combination with the cost of material per ton will give the approximate cost per unit, to which must be added a labor and superinten- dence allowance. CARPENTRY. The item of carpentry and glaziers with ref- erence to windows is subject to wide variation, according to the location of the building and the number of open sides, and also the supply of material is purely a local proposition and in general it will be more economical to obtain estimates locally for frames and windows com- plete. APPENDIX TEMPERATURE AND BAROMETRIC FACTORS. Barometer. Temp. 28.5 28.6 28.7 28.8 28.9 29.0 29.1 29.0 29.3 29.4 105. .820 .823 .827 .830 .833 .836 .839 .842 .845 .848 104. .823 .827 .830 .833 .836 .839 .842 .845 .848 .851 103. .827 .830 .834 .837 .840 .843 .847 .849 .852 .855 102. .830 .834 .837 .840 .843 .847 .850 .853 .856 .859 101. .834 .837 .840 .843 .846 .850 .853 .856 .859 .862 100. .837 .840 .843 .846 .849 .853 .856 .859 .862 .865 99. .840 .844 .846 .850 .853 .857 .860 .863 .866 .869 98. .844 .847 .850 .853 .856 .860 .863 .866 .869 .872 97. .847 .850 .853 .856 .859 .863 .866 .870 .873 .876 96. .850 .854 .857 .860 .863 .867 .870 .873 .876 .879 95. .854 .857 .860 .863 .866 .870 .873 .876 .879 .882 94. .857 .860 .863 .866 .869 .873 .876 .879 .882 .885 93. .860 .863 .866 .869 .872 .876 .879 .883 .886 .889 92. .863 .866 .869 .872 .875 .879 .882 .885 .889 .892 91. .866 .869 .872 .875 .879 .882 .885 .889 .892 .895 90. .869 .872 .875 .878 .881 .885 .888 .892 .895 .898 89. .871 .875 .878 .882 .885 .889 .892 .895 .898 .901 88. .875 .878 .881 .885 .888 .892 .895 .898 .901 .904 87. .878 .881 .884 .888 .891 .895 .898 .901 .904 .907 86. .881 .884 .887 .890 .894 .898 .901 .904 .907 .910 85. .884 .887 .890 .893 .896 .900 .903 .906 .909 .913 84. .887 .889 .893 .896 .899 .903 .906 .909 .912 .915 83. .889 .892 .895 .899 .902 .906 .909 .912 .915 .918 82. .892 .895 .898 .901 .905 .906 .911 .914 .918 .921 81. .895 .898 .901 .905 .908 .911 .914 .917 .921 .924 80. .898 .901 .904 .907 .910 .914 .917 .920 .923 .927 79. .901 .904 .907 .910 .914 .917 .920 .923 .926 .930 78. .904 .906 .909 .913 .916 .919 .923 .926 .929 .932 77. .906 .909 .912 .915 .919 .922 .925 .928 .931 .935 76. .909 .911 .915 .918 .921 .925 .928 .931 .935 .938 75. .911 .914 .917 .921 .924 .928 .931 .934 .937 .940 74. .914 .917 .920 .924 .927 .930 .933 .937 .940 .943 73. .917 .920 .923 .926 .930 .933 .936 .940 .943 .946 72. .920 .923 .925 .929 .932 .935 .939 .942 .945 .949 71. .922 .925 .928 .931 .935 .938 .941 .944 .948 .951 70. .925 . .927 .931 .934 .937 .941 .944 .947 .950 .954 69. .927 .930 .938 .937 .940 .944 .947 .950 .953 .957 68. .930 .932 .936 .939 .942 .946 .949 .952 .956 .959 182 Elements of Water Gas TEMPERATURE AND BAROMETER FACTORS. Barometer. (Continued. ) Temp. 28.5 28.6 28.7 28.8 28.9 29.0 29.1 29.0 29.3 29.4 67. .932 .935 .938 .942 .945 .949 .952 955 .959 .962 66. .935 .938 .941 .944 .948 .951 .954 958 .961 .964 65. .938 .941 .944 .947 .950 .954 .957 960 .963 .967 64. .941 .943 .946 .949 .952 .956 .959 963 .966 .969 63. .943 .945 .949 .952 .955 .959 .962 965 .969 .972 62. .945 .947 .951 .954 .958 .961 .964 968 .971 .975 61. .947 .950 .954 .957 .961 .964 .967 971 .974 .977 60. .950 .952 .956 .959 .963 .966 .969 973 .976 .980 59. .952 .955 .959 .962 .966 .969 .972 976 .979 .983 58. .955 .957 .961 .964 .968 .971 .975 978 .981 .985 57. .957 .960 .963 .967 .970 .974 .977 980 .984 .988 56. .960 .962 .966 .969 .973 .976 .979 982 .986 .990 55. .962 .965 .968 .972 .975 .979 .982 985 .989 .993 54. .965 .967 .970 .974 .977 .981 .984 988 .991 .995 53. .967 .969 .973 .976 .980 .983 .986 990 .993 .997 52. .969 .971 .975 .978 .982 .985 .989 992 .996 .999 51. .971 .974 .977 .981 .984 .988 .991 995 .998 .002 50. .974 .976 .980 .983 .987 .990 .994 997 1.001 .004 49. .976 .979 .982 .986 .989 .993 .996 1 000 1.003 .007 48. .979 .981 .985 .988 .992 .995 .999 1 002 .006 .009 47. .981 .984 .987 .991 .994 .998 .001 1 005 .008 .012 46. .984 .986 .990 .993 .997 .000 .004 1 007 .011 .014 45. .986 .989 .992 .996 .999 .003 .006 1 010 .013 .017 44. .989 .991 .994 .996 1.001 .005 .008 1 012 .015 .019 43. .991 .993 .996 1.000 1.004 .008 .011 1 015 .018 .022 42. .993 .995 .999 1.003 1.006 .010 .013 1 017 .020 .024 41. .995 .998 1.001 1.005 1.009 .012 .016 1 019 .022 .026 40. .998 1.000 1.003 1.007 1.011 .015 .018 1 022 .025 .028 39. 1.000 1.003 1.006 1.010 1.013 .017 .020 1 024 .027 .031 38. 1.003 1.005 1.009 1.012 1.016 .020 .023 1 027 .030 .034 37. 1.005 1.007 1.011 1.015 1.018 .022 .025 1 029 .032 .036 36. 1.007 1.009 1.013 1.017 1.020 .024 .027 1 031 .035 .038 3.3. 1.009 1.012 1.015 1.019 1.023 .026 .030 1 033 .037 .040 34. 1.012 1.014 1.018 1.022 1.025 .029 .032 1 036 .040 .043 33. 1.014 1.016 1.020 1.024 1.027 .031 .034 1 038 .042 .046 32. 1.016 1.019 1.023 1.027 1.030 L.034 .037 1 041 .044 L.048 .31. 1.019 1.021 1.025 1.029 1.032 1.036 .039 1 .043 .047 .050 30. 1.021 1.023 1.027 1.031 1.034 1.038 .042 1 045 .049 .053 29. 1.023 1.026 1.030 1.033 1.037 1.040 .044 1.048 .051 .055 28. 1.026 1.028 1.032 1.036 1.039 1.043 .047 1 050 .0.34 .058 Elements of Water Gas TEMPERATURE AND BAROMETER FACTORS. 183 Barometer. (Continued. ) Temp. 28.5 28.6 28.7 28.8 28.9 29.0 29.1 29.0 29.3 29.4 27. 1.028 1.030 1.034 1.038 .041 1.045 1.049 1.053 1 .056 1.060 26. .030 1.033 1.037 1.041 .044 1.048 1.051 1.055 1 .059 1.082 25. .033 1.035 1.039 1.043 .046 1.050 .054 1.057 1 .061 1.065 24. .035 1.037 1.041 1.045 .048 1.052 .056 1.060 1 .064 1.067 23. .037 1.040 1.044 1.048 .061 1.055 .058 1.062 1 .066 1.069 22. .040 1.042 1.046 1.050 .063 1.057 .061 .065 1 .068 .072 21. .042 1.044 1.048 .052 .065 1.069 .063 .067 1 .071 .074 20. .044 1.047 1.051 .065 .058 1.062 .065 .069 1 .072 .076 19. .047 1.050 1.054 .068 .061 1.065 1.068 .072 1 .076 .079 18. .050 1.052 1.056 .060 1.063 1.067 1.070 .074 1 .078 .082 17. 1.052 1.055 1.059 .062 1.066 1.069 1.073 .076 1 .080 .084 16. 1.065 1.057 1.061 .064 1.068 1.071 1.075 .079 1 .063 .086 15. 1.057 1.059 1.063 .066 1.070 1.074 .077 .061 1 .085 .068 14. 1.069 1.062 1.066 1.069 1.073 1.076 .080 .084 1 .087 .091 13. 1.082 1.064 1.068 1.071 1.075 1.078 .082 .086 1 .090 .094 12. 1.064 1.066 1.070 1.073 1.077 1.080 .084 .088 1 .092 .096 11. 1.066 1.069 1.073 1.076 1.080 1.083 .067 .091 1 .095 .098 10. 1.069 1.071 1.075 1.078 1.082 1.086 .090 .093 1 .097 .101 9. 1.071 1.073 1.077 1.081 1.084 1.088 .092 .095 1 .099 .103 8. 1.073 1.076 1.079 1.083 1.087 1.090 .094 .098 1 .102 .105 7. 1.076 1.078 1.082 1.085 1.089 1.093 .096 .100 1 .104 .108 6. 1.078 1.080 1.084 1.088 1.091 1.095 .099 .103 1 .107 .111 5. 1.080 1.083 1.087 1.090 1.094 1.098 .102 .105 1 .109 .113 4. 1.083 1.085 1.089 1.092 1.096 1.100 .104 .108 1 .111 .115 3. 1.085 1.088 1.092 1.095 1.099 1.103 .107 .111 1 .114 .118 2. 1.088 1.090 1.094 1.098 1.101 1.105 .100 .113 1 .117 .121 1. 1.090 1.093 1.097 1.100 1.104 1.108 .111 .115 1 .119 .123 0. 1.093 1.095 1.099 1.103 1.107 1.111 .114 1.118 1 .122 .126 184 Elements of Water Gas BAROMETER. Temp. 29.5 29.6 29.7 29.8 29.9 30.0 30.1 30.2 30.3 30.4 30.5 105. .851 .855 .858 .861 .864 .867 .871 .874 .878 .881 .884 104. .854 .858 .861 .864 .867 .871' .874 .878 .881 .884 .887 103. .858 .862 .865 .868 .871 .874 .878 .881 .885 .888 .891 102. .862 .865 .868 .871 .874 .878 .881 .885 .888 .891 .894 101. .865 .868 .872 .875 .878 .882 .885 .888 .891 .895 .898 100. .868 .872 .875 .878 .881 .885 .888 .891 .895 .898 .901 99. .872 .876 .879 .882 .885 .889 .892 .895 .898 .902 .905 98. .875 .879 .882 .885 .888 .892 .895 .898 .902 .905 .908 97. .879 .882 .885 .888 .891 .894 .898 .901 .905 .908 .911 96. .882 .886 .889 .892 .895 .898 .901 .904 .908 .911 .914 95. .885 .889 .892 .895 .898 .901 .904 .907 .911 .914 .918 94. .888 .892 .895 .898 .901 .904 .907 .911 .914 .918 .921 93. .891 .895 .898 .901 .904 .907 .910 .914 .918 .921 .924 92. .894 .898 .902 .904 .907 .910 .914 .917 .921 .924 .928 91. .898 .902 .905 .908 .911 .914 .917 .921 .924 .928 .931 90. .901 .905 .908 .911 .914 .917 .920 .924 .927 .931 .934 89. .904 .907 .910 .914 .917 .920 .923 .927 .931 .934 .937 88. .907 .910 .913 .917 .920 .923 .926 .930 .934 .937 .940 87. .910 .913 .916 .920 .923 .926 .929 .933 .937 .940 .943 86. .913 .916 .919 .923 .926 .929 .932 .936 .940 .943 .946 85. .916 .919 .922 .926 .929 .932 .936 .939 .943 .946 .949 84. .919 .922 .925 .928 .932 .935 .939 .942 .946 .949 .952 83. .921 .924 .928 .931 .935 .938 .942 .945 .949 .952 .955 82. .924 .927 .931 .934 .937 .941 .945 .948 .951 .954 .958 81. .927 .930 .934 .937 .940 .944 .948 .951 .954 .957 .960 80. .930 .933 .937 .940 .943 .946 .950 .954 .957 .960 .963 79. .933 .936 .939 .943 .946 .949 .953 .956 .960 .963 .967 78. .936 .939 .942 .946 .949 .952 .956 .959 .962 .966 .969 77. .938 .942 .945 .948 .951 .955 .958 .962 .965 .968 .972 76. .941 .944 .948 .951 .954 .958 .961 .964 .968 .971 .975 75. .943 .947 .950 .954 .957 .960 .963 .967 .971 .974 .978 74. .947 .950 .953 .957 .960 .963 .966 .970 .973 .977 .980 73. .949 .953 .956 .960 .963 .966 .969 .972 .976 .980 .983 72. .952 .955 .959 .962 .965 .968 .972 .975 .979 .982 .986 71. .954 .958 .961 .965 .968 .971 .975 .978 .981 .985 .989 70. .957 .960 .964 .967 .970 .974 .977 .980 .984 .988 .991 69. .960 .963 .967 .970 .973 .977 .980 .983 .987 .990 .994 68. .962 .966 .969 .972 .976 .979 .983 .986 .989 .993 .997 67. .965 .968 .972 .975 .979 .982 .985 .989 .992 .996 1.000 66. .968 .971 .974 .978 .981 .985 .988 .992 .995 .998 1.002 65. .970 .973 .977 .980 .984 .987 .991 .994 .997 1.001 1.005 Elements of Water Gas BAROMETER. (Continued.) 185 Tern p 29 "i 29 6 29.7 29.8 29.9 30.0 30.1 30.2 30.3 30.4 30 5 64. 63. .973 975 .976 .979 . .980 .982 .983 .985 .986 .989 .990 .993 .994 .996 .997 1.000 1.000 1.003 1.004 1.006 1.008 1 010 62. .978 .981 .985 .988 .991 .995 .999 1.002 1.006 1.009 1.013 61. .981 .984 .987 .991 .994 .998 1.001 1.004 1.008 1.011 1.015 60. .983 .986 .990 .993 .997 1.000 1.004 1.007 1.010 1.014 1.017 59. .986 .989 .992 .995 .999 1.003 1.006 1.010 1.013 1.016 1.020 58. .988 .992 .995 .998 1.002 1.005 1.009 1.012 1.016 1.019 1.023 57. .991 .994 .997 1.000 1.004 1.007 1.011 1.014 1.018 1.021 1.025 56. .993 .996 1.000 1.003 1.007 1.010 1.014 1.017 1.021 1.024 1.028 55. .996 .999 1.002 1.006 1.009 1.013 1.016 1.020 1.023 1.027 1.030 54. .998 1.001 1.005 1.008 1.012 1.015 1.019 1.022 1.026 1.029 1.033 53. 1.000 1.004 1.007 1.011 1.014 1.018 1.021 1.025 1.028 1.031 1.035 52. 1.003 1.006 1.010 1.013 1.017 1.020 1.024 1.027 1.031 1.034 1.038 51. 1.005 1.009 1.012 1.016 1.019 1.023 1.026 1.030 1.033 1.037 1.040 50. 1.008 1.011 1.015 1.018 1.022 1.025 1.029 1.032 1.036 1.039 1.043 49. 1.010 1.014 1.017 1.021 1.024 1.028 1.031 1.035 1.038 1.042 1.045 48. 1.013 1.016 1.020 1.023 1.027 1.030 1.034 1.037 1.041 1.044 1.048 47. 1.015 1.019 1.022 1.026 1.029 1.032 1.030 1.040 1.045 1.047 1.050 46. 1.018 1.021 1.025 1.028 1.032 1.035 1.039 1.042 1.046 1.049 1.063 45. 1 090 1 024 1 027 1 031 1 034 1.038 1.041 1 045 1 048 1 052 1 056 44. 1.022 1.026 1.029 1.033 1.036 1.040 1.043 1.047 1.050 1.054 1.058 43. 1.025 1.029 1.082 1.036 1.039 1.043 1.046 1.050 1.053 1.057 1.060 42. 1.027 1.031 1.034 1.038 1.041 1.045 1.048 1.052 1.055 1.069 1.063 41. 1.030 1.032 1.037 1.041 1.044 1.048 1.051 1.055 1.058 1.062 1.065 40. 1.032 1.036 1.039 1.043 1.046 1.050 1.054 1.057 1.060 1.064 1.068 39. 1.035 1.039 1.042 1.045 1.049 1.053 1.056 1.059 1.063 1.066 1.070 38. 1.037 1.041 1.044 1.048 1.051 1.055 1.058 1.062 1.065 1.069 1.073 37. 1.039 1.043 1.046 1.050 1.053 1.057 1.060 1.064 1.068 1.072 1.076 36. 1.042 1.045 1.049 1.052 1.066 1.060 1.063 1.067 1.071 1.074 1.078 35. 1.044 1.048 1.051 1.055 1.058 1.0C2 1.065 1.069 1.073 1.076 1.081 34. 1.047 1.050 1.054 1.057 1.061 1.064 1.068 1.072 1.075 1.079 1.083 33. 1.049 1.053 1.056 1.060 .063 1.067 1.070 1.074 1.078 1.082 1.086 32. 1.051 1.055 1.068 1.062 .066 1.069 1.073 1.077 1.081 1.085 1.089 31. 1.054 1.057 1.061 1.064 .068 1.072 1.075 1.079 1.083 1.087 1.091 30. 1.056 1.060 1.063 1.067 .071 1.074 1.078 1.082 1.086 1.090 1.094 29. 1.058 1.062 1.065 1.069 .073 1.076 1.080 1.084 1.088 1.09-2 1.006 28. 1.061 1.065 1.068 1.072 .075 1.079 1.083 1.087 1.091 1.093 1.099 27. 1.063 1.067 1.070 1.074 .078 1.082 1.086 1.090 1.094 1.098 1.102 26. 1.066 1.069 1.073 1.077 .080 1.084 1.088 1.092 1.096 1.100 1.104 25. 1.068 1.072 1.075 1.079 .083 1.086 1.090 1.094 1.098 1.102 1.106 24. 1.071 1.074 1.078 1.081 .085 1.089 1.093 1.097 1.101 1.105 1.109 23. 1.073 1.076 1.080 1.084 .088 1.092 1.095 1.099 1.103 1.107 l.lll 186 Elements of Water Gas BAROMETER. (Continued..) Temp. 29.5 29.6 29.7 29.8 29.9 30.0 30.1 30.2 30.3 30.4 30.5 22. .075 1.079 1.083 1.086 1.090 1.094 1.098 1.102 .106 1.110 ] L.114 21. .078 1.081 .085 1.089 1.093 1.096 1.100 1.104 .108 1.112 ] L.116 20. .060 1.084 .087 1.091 1.095 1.099 1.103 1.107 .111 1.115 ] L.118 19. .083 .087 .090 1.093 1.098 1.102 1.106 1.110 .114 1.118 1.121 18. .085 .089 .093 1.097 1.100 .104 1.108 1.112 .116 1.120 L.124 17. .088 .091 .095 1.099 1.102 .106 1.110 1.114 .118 1.122 L.126 16. .090 .094 .099 .101 1.105 .109 1.113 1.117 .121 1.125 1.129 15. .092 .096 .100 .103 1.107 .111 1.115 1.119 .123 1.127 1.131 14. .095 .099 .102 L.106 1.110 .114 1.117 1.121 .125 1.129 1.133 13. .097 .101 .105 .109 1.112 .116 1.120 1.124 .128 1.132 1.136 12. .100 .103 .107 .111 1.115 .119 1.122 1.126 .130 1.134 1.138 11. .102 .106 .110 .114 1.117 .121 1.125 1 129 133 1 137 141 10. .105 .108 .112 .116 1.120 .123 1.127 1.131 .135 1.139 L.143 9. .107 .111 .114 .118 1.122 .126 1.130 1.133 .137 1.141 1.145 8. .109 .113 .117 .121 1.125 .128 1.132 1.136 .140 1.144 1.148 7. .112 .115 .119 .123 1.127 .131 1.135 1.139 .143 1.147 .151 6. .114 .118 .122 .126 1,130 .133 1.137 1.141 1.145 1.149 .153 5. 1.117 .120 .124 .128 1.132 ] .136 1.140 1.144 1.148 1.152 .156 4. 1.119 .123 .126 .130 1.134 .138 1.142 1.146 1.150 1.154 .158 3. 1.122 .126 .129 .133 1.137 1 .141 1.145 1.149 1.153 1.157 .161 2. 1.125 .128 .132 .136 1.140 ] .144 1.148 1.152 1.156 1.160 .164 1. 1.127 1.131 .135 .139 1.143 .146 1.150 1.154 1.158 1.162 .166 0. 1.130 1.133 .137 .141 1.145 .149 1.153 1.157 1.161 1.165 .169 TEMPERATURE FACTORS. Note: The preceding factors are calculated from the formula 17. 64 (b a) f= in which (b) is the height of the barometer, (a) is the 460 + t tension of aqueous vapor, and (t) is the temperature fahrenheit. For instance, if the barometer is 30.0 and the temperature 100, the factor will be: 17.64(301.918) f= =.885 460 + 100 Elements of Water Gas 187 AQUEOUS VAPOR TENSION. Temp. F Mercury ins. Temp. Mercury. 1 .046 51 = .374 2 - .048 52 = .388 3 - .050 53 = .403 4 _ .052 54 = .418 5 .054 55 = .433 6 = .067 56 = .449 7 .060 57 = .465 8 _ .062 58 = .482 9 = .065 59 = .500 10 ,.068 60 = .518 11 .071 61 = .537 12 .074 62 = .556 13 .078 63 = .576 14 = .084 64 = .506 15 = .086 65 = .617 16 .090 66 = .639 17 .004 67 = .661 18 .098 68 = .685 19 .103 69 = .708 20 .106 70 = .733 21 = .113 71 = .759 22 = .118 72 = .785 23 = .123 73 = .812 24 = .129 74 = .840 25 = .135 75 = .868 26 = .141 76 = .877 27 = .147 77 = .927 28 = .153 78 = .958 29 = .160 79 = .990 30 = .167 80 = 1.023 31 = .174 81 = 1.057 32 = .181 82 = 1.092 33 = .188 83 = 1.128 34 = .196 84 = 1.165 35 = .204 85 = 1.203 36 = .212 86 = 1.242 37 = .220 87 = 1.282 38 = .229 88 = 1.323 39 = .238 89 = 1.366 40 = .247 90 = 1.401 41 = .257 91 = 1.455 42 .267 92 = 1.501 43 = .277 93 = 1.548 188 Elements of Water Gas AQUEOUS VAPOR TENSION. (Continued.) Temp. F Mercury ins. Temp. Mercury. 44 .288 94 45 .299 95 46 .311 96 47 .323 97 48 .335 98 49 .348 99 50 .361 100 596 646 751 .918 Elements of Water Gas 189 CENTIGRADE AND FAHRENHEIT SCALE. Cent. Fahr. Cent, Fahr. Cent. Fahr. Cent. Fahr. = 32. 26 = 78.8 51 B 123.8 76 a 168.8 1 = 33. 8 ' 27 80.6 i>-2 Bl 125.6 77 a 170.8 2 = 35. 6 28 = 82.4 a = 127.4 78 a 172.4 3 = 37. 4 29 33 84.2 54 B 129.2 79 - 174.2 4 = 39. 2 30 33 86.0 55 B 131.0 80 a 176.0 5 = 41. 31 S 87.8 H B 132.8 81 B 177.8 6 = 42. 8 32 = 89.6 57 = 134.6 82 = 179.6 7 = 44. 6 33 = 91.4 H B 136.4 83 a 181.4 8 = 46. 4 34 33 93.2 59 = 138.2 84 a 183.2 9 = 48. 2 35 =S 95.0 00 B 140.0 85 a 185.0 10 = 50.0 36 ss 96.8 61 B 141.8 86 - 186.8 11 = 51. 8 37 33 98.6 88 a 143.6 87 i 188.6 12 = 53. 6 38 33 100.4 68 a 145.4 88 a 190.4 13 = 55. 4 39 3= 102.2 81 = 147.2 89 a 192.2 14 = 57. 2 40 33 104.0 65 rr 149.0 90 B 194.0 15 = 59. 41 S3 105.8 88 B 150.8 91 = 195.8 16 = 60. 8 42 3S 107.6 67 35 1-52.6 92 = 197.6 17 = 62.6 43 33 109.4 08 B 154.4 93 s 199.4 18 = 64. 4 44 S3 111.2 80 a 156.2 94 a 201.2 19 = 66. 2 45 33 113.0 70 a 158.0 95 B 203.0 20 = 68. 46 3= 114.8 71 a 159.8 96 = 204.8 21 = 69. 8 47 B 116.6 7:2 s 161.6 97 = 206.6 22 = 71. 6 48 S3 118.4 7:-: a 163.4 98 a 208.4 23 = 73. 4 49 = 120.2 74 a 165.2 99 a 210.2 24 = 75. 2 50 = 122.0 75 ^ 167.0 100 212.0 25 = : 77.0 SPECIFIC GRAVITY OF GASES. Weight of 1 Cubic Foot in Grains at60F. Cubic Feet Spec. Grav. and 30.0 Equal to Gas. (Air=1.00) Barometer 1 Pound. Hydrogen Methane Carbon M Olefiant < Nitrogen Oxygen ( Hydrogen Carbon E Water V: (H 2 ) (CH 4 ) [onoxide (CO) 3as (OH.V.. 0.06926 0.558 0.9678 0.971 0.97137 1.10563 1.1912 1.529 0.615 37.15 297.20 520.10 520.10 520.10 594.40 631.54 817.30 334.85 188.42 23.65 13.46 13.46 13.46 11.77 11. (W 8.56 20.93 (N 2 ) :o 2 > . Sulp >i"Xi'lt ipor i Z~ 4> hide ; (CO ;H.Q). (H.S) ) " 190 Elements of Water Gas BOILING POINTS OF WATER AT DIFFERENT PRESSURES. Temp. F Bar. ins. Temp. Bar. ins. 184 16.676 201 28.937 186 17.047 202 24.441 186 17.421 203 25.014 187 17. 803 204 2~).4<>S 188 18.196 205 25.992 189 18.593 206 26.529 190 18.992 207 27.068 191 19.407 208 27.614 192 19.822 209 28.183 193 20.254 210^ 28.744 194 20.687 211 29.331 195 21.124 212 29.922 196 21.576 213 30.516 197 22.030 214 31.120 198 22.498 215 31.730 200 23.454 216 32.350 RETURN TO the circulation desk of any University of California Library or to the NORTHERN REGIONAL LIBRARY FACILITY Bldg. 400, Richmond Field Station University of California Richmond, CA 94804-4698 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS 2-month loans may be renewed by calling (510)642-6753 1 -year loans may be recharged by bringing books to NRLF Renewals and recharges may be made 4 days prior to due date. DUE AS STAMPED BELOW 2 2000 U. C. BERKELEY VB 15408 UNIVERSITY OF CALIFORNIA LIBRARY