GAS FOR THE OPERATION OF PUMPS

GAS FOR THE OPERATION OF PUMPS

(Continued from last week.)

Although the gas engine-operated pump is at present not considered to any extent for large city water works, yet it is interesting to note that for towns of 50,000 population and less it presents an ideal source of water supply. Take for example the town of Manchester, Mass., the operating data of which is at hand in the shape of an actual report from Chief Engineer Raymond C. Allen (Assoc. Mem. Amer. Soc. C. E.). As this is an interesting lay-out, and of a type frequently encountered in other towns, a full description will be found to contain data of interest to the owners of small water works. I quote from Mr. Allen’s rqiort as follows:

“In 1908 and 1909 the town of Manchester, Mass., enlarged its water supply and installed new pumping machinery. There are two stations pumping water, one at Gravel Pond, so called, and one from driven wells, called the Home plant. At the Gravel Point plant is a duplicate installation of 65 horsepower gas producers made by the Smith Gas Power Company, 65 horsepower gas engines made by the National Meter Company, and 1,000,000 gallon pumps made by the Goulds Manufacturing Company. At the home plant is a similar duplicate installation of 50 horsepower and 750,000 gallon capacity, respectively, the several units being supplied by the above-mentioned manufacturers. The Gravel Pond installation pumps against a total static head of about 240 feet and the home plant against a total static head of 270 feet. These plants were installed under the direction of the writer and have been in continuous operation since they were first started. Upon the completion of the installation of the new plant at Gravel Pond in 1909 the station was at once set to work to pump the water to the town for the summer, the time when the local load runs to 1,200,000 gallons per day against some 200,000 gallons in winter. At the same time the old station, then equipped with compound duplex steam pumps, was dismantelcd and that station equipped with a similar plant to that at the Gravel Pond station. It was not until late in the fall that the old station was again in operation, and for the entire summer the Gravel Pond installation, under the management of one of the former steam engineers with some three weeks’ instruction, supplied the town with water without difficulty or delay of any sort. Upon the completion of the installation at the home station and its being placed in commission, it entered upon its work and has continued in the same manner as the Gravel Pond plant.

Operation of the Plants

“The operation of the plants has not only been reliable, out almost monotonous in so far as anything unusual in the way of repairs is concerned, there having been very little required. It has also been most economical, the station duties running from 80,000,000 foot-pounds per 100 pounds of coal for the plants running three days per week, six hours per day, to around 140,000,000 in the long and continuous rnns of the summer. Taken at random, the month of August, 1911, from the log of the home plant, the pumping was done every day as follows:

FIG. 7—PUMPING PLANT LOCATED AT ARDMORE, PA.

“This is a typical month for this station in the summer, and any other month will afford similar figures, varying only as the rain or some other factor influences the consumption of water. The last year of operation of the discarded steam plant showed the following:

FIG. 8.—VERTICAL SINGLE CYLINDER GASOLINE ENGINE.

whereas with the gas plant, for the year ending January, 1911, the record shows the following:

“The local authorities having the department in charge are well pleased with their experience thus far and believe that under local conditions and for the small size of the plants they have as economical a plant as could be obtained, and that they have it without any sacrifice in reliability.”

In Fig. 4 will be seen illustration of both the exterior and interior of the Gravel Point plant, and attention is called to the compact and attractive nature of the installation. Another installation of similar design but smaller size is installed at the town of Stanley, VVis. This plant, which is shown in Fig. 5, was installed by the Foos Gas Engine Company, of Springfield. O. Data as to operating results are not available, but it is said that the plant is in every way satisfactory and has been operating steadily for several years. From the foregoing it will be noted that the gas-driven pumping plant for the small town is in every way satisfactory, and, did space permit, the names of many others of similar size could be given all of which are doing equally well. Having touched upon the results obtained in practise in municipal pumping (large and small), attention is called to what might be termed industrial pumping. By this is meant that class of manufacturing which necessitates the handling of large quantities of water. For example, in the plate glass industry a steady supply of water is required in the grinding and polishing processes, and a gas-driven plant which has been in actual service for the past 10 years, the operating costs and general data of which are to hand, is here considered. At Ford City, Pa., are located the works of the Pittsburgh Plate Glass Company, and it is here that we find a large pumping plant entirely handled by gas engines.

Plant in Service Ten Years

Plant shown in Fig. 6 consists of five pumping units, each comprising a three-cylinder 11×12 Westinghouse vertical gas engine, connected through a clutch with a geared single-acting Stilwell-Bierce & Smith-Vaile triplex pump 10×15. This plant has a daily capacity of 12,000,000 gallons per 24 hours, the water being discharged into a 30-inch main connecting with a reservoir three-quarters of a mile distant, having an elevation of 200 feet above the pumps, From the reservoir water is also supplied to the town. Ten years’ use of this plant has shown that repairs and replacements are so small an item of expense as to be hardly worthy of consideration, and the following data taken from a month’s observation of operation gives a fairly average cost of operation and will be instructive on account of the completeness of the data. coupled with the knowledge that the plant has been in operation for so long a period:

FIG. 9—PORTABLE OUTFIT FOR PUMPING OUT EXCAVATION.

This plant operates on natural gas, having an average heat value of 1,000 B. t. u. per cubic foot, it is an interesting matter of record that this plant displaced a steam plant of the same capacity and having apparently the same load conditions. The cost of operating the steam plant averaged $1,700 per month for fuel alone, and without taking into consideration the lessened attention and labor with the gas engines, the gas plant showed a net saving of $1,520 per month, or $18,240 per annum. These figures of economies made, when taken in consideration with the fact that the plant has been operating 10 years, prove beyond doubt the advantages of gas power under some conditions. Yet another pumping plant, of much smaller capacity, is shown in Fig. 7, demonstrating that the field is by no means confined to installations of large capacity. This plant, which comprises Backus gas engines geared to Deming pumps, is located at Ardmore, Pa., the plant being installed to handle the sewage of that city, the daily load consisting of pumping 750,000 gallons of sewage against a total head of 175 feet. Acurate operating costs on this installation were not obtainable, but the plant is in every way satisfactory and handles the load with ease and freedom from breakdowns. Not only has the gas engine successfully supplied the large and moderate pumping station with a reliable and efficient type of power, but it is also applicable to even smaller installations, such as little villages which have hitherto been unable to even consider fire protection. Not only that, but pumping units are now on the market sufficiently small in capacity to suit the individual needs of farms, isolated dwellings and similar fields.

In Fig. 8 is shown a vertical single-cylinder gasoline engine of 5 horsepower belted to a centrifugal pump. This simple and inexpensive outfit is manufactured by the International Gas Engine Company, which also builds the handy portable outfit shown in Fig. 9, designed to replace hand power for pumping out cellars, excavations, etc. These “Ingeco” outfits, although only on the market a short time, are meeting with great success. Having now given a few of the fields in which the gas-driven engine is successfully providing the power for the operation of pumps, it may be well to touch upon the fuels that this type of engine is capable of using, and the conditions that decide in each case which of the several fuels will best meet the need of the case.

The Subject of Fuel

Considering the installations as treated in this article, we have, firstly, the high pressure fire service. Here it will be readily noted that the foremost consideration is ability to operate at full load from a standing start at a moment’s notice, while it is also necessary that the yearly operating cost should be a minimum. In this case the conditions were best met by the use of illuminating gas furnished by the local gas company. True, the cost per heat unit of this gas was far in excess of the cost of “producer” gas, if they had cared to install their own plant, but other considerations entered into the problem which showed that under the circumstances it was actually cheaper and more desirable to buy the gas than to make it themselves. This was due to several reasons—the plant was only to operate intermittently, which would mean banked fires necessary at all times, and by use of the city gas supply they had always at their command the immense gas reservoirs (holders) from which to draw their fullest capacity at an instant notice; also, having no private gas plant, they dispensed with the need of a crew to operate it, and finally, the large investment necessary for a plant of this capacity could be avoided by purchasing their gas as they needed it. In the case of town pumping plants where 24-hour service was desired, a producer plant to manufacture their own gas from coal was justified, and the economy therefrom enabled the successful showing referred to. In the case of the manufactory natural gas was available at p price that obviated the consideration of gas producers, hence their absence in an installation that otherwise would have used them. In the small portable and stationary plants extreme simplicity and ability to operate without attendance is the prime consideration, hence the fact that they operate on gasoline. However, this latter fuel is fast being boosted in price to a point where it will be too much of a luxury to consider as fuel for any engine over 10 horsepower, but even that need not cause uneasiness, for gas engine builders have always shown an ability to cope with every obstacle as it is raised, and coincident with the rise in the price of gasoline the manufacturers are turning their attention to engines of similar design to those used for gasoline, only so modified as to admit of their using kerosene, or even heavier and cheaper oils.

In Fig. 10 will be seen one of the first engines designed to meet the changing price in oil fuels This engine, known as “Adams-Wisconsin,” is designed especially for operation on kerosene, distillate and heavier oils, on which it operates perfectly with no more attention than its predecessors required when running on gasoline. Inspecrion of big. 9 will show that the engine, which is geared to a triplex pump, possesses many features hitherto found only on engines of, say, 500 horsepower and larger—features which have hitherto been considered too costly to incorporate in small units, but which nevertheless made for the success of the aforesaid large units. For example, the inlet and exhaust valves, each in removable cages, located so as to operate vertically, the inlet opening downward with the exhaust situated at the lowest part of the cylinder, thus insuring good scavenging of not only the exhaust, but any loose carbon or foreign matter that might enter through the air inlet. These valves are not driven by cams, but employ eccentrics, which insure noiseless operation. Indications are to the effect that the other builders of small engines will shortly bring out units designed to operate on the cheap oils, so that the rise in the price of any one fuel need not discourage the prospective buyer when he considers that he has a choice of fuels ranging over coal, wood, peat, natural gas, illuminating gas, gasoline, kerosene, distillate etc. and it is natural to suppose that, no matter where the plant is located, one or more of these fuels will be available for the operation of the gas-driven pumping plant.

FIG. 10—ENGINE DESIGNED TO OPERATE WITH HEAVY OILS.

GAS FOR THE OPERATION OF PUMPS

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GAS FOR THE OPERATION OF PUMPS

It is a matter of common knowledge that the gasoline-operated fire engine is fast displacing the horse-drawn, steam-operated type, which for so many years did excellent service, but it is not so generally known that gas has also displaced steam to a very much larger extent, and with more marked economy, in stationary water works and pumping stations. That the gas engine is a success as a power unit for all classes of work is no longer a disputed fact, hut few outside of those actually in touch with that class of engineering realize the strides that gas engines nave made within the past few years. Actual results and specific installations are always of more interest to the public than scientific data, and it is therefore desired to enter into the practical side of the case by giving information of work already accomplished in daily service, so that one may learn the very great economy obtainable by the use of this form of power. Of course., it is not desired to create the impression that the steam plant is obsolete and about to be relegated to the scrap heap; far from it; but it will be shown how in many (blit by no means all) cases gas power will do the pumping as reliably and much more cheaply than can otherwise be accomplished.

FIG. 1. ORIGINAL ENGINE AND PUMP ROOM, PHILADELPHIA.

Let us first consider “high pressure” fire service. Here we have a class of work to perform where the plant spends most of its time idle, hut must be instantly available to its full capacity. Jt is obvious that it is desirable to have the minimum “standby losses,” such as keeping fires ready under a battery of boilers, with fireroom crews at all times on duty. But, with a steam-operated installation, such standby loss cannot be avoided. When the city of Philadelphia first considered a high pressure lire service this very point was raised, and after mature consideration it was decided to install a battery of gas engines, each geared to a triplex pump. In Fig. 1 is shown the original engine and pump room, and the following data as to practical operating results are instructive. The plant, which was placed in service in 1904, consisted originally of seven 300 horsepower Westinghouse, three-cylinder vertical engines, each geared to a 2,000,000 gallon Dean triplex pump, and two similar units of 125 horsepower, each geared to 750,000 gallon pumps, all to operate at 300 pounds water pressure. The acceptance test under service conditions was run on March 1, 1004, and gave the following satisfactory service.

Since that date the city of Philadelphia has ordered and installed 10 more units of 1100 horsepower of the same make, thus bringing the total up to 5,350 horsepower, the second power station of the high pressure system being shown in Fig. 2. while an interior view is shown in Fig. 3. Attention is called to the attractive type of building permissible with this type of installation, there being no unsightly stack or other evidence that it is a power plant, while the internal arrangement as shown in Fig. 3 shows the small amount of space required to properly house this type of pumping installation. The records of this high pressure plant (two stations) shows that in all the years that it lias been in service it has been ready at an instnat’s notice to deliver full capacity, and that the operating and overhead charges show substantial saving over results obtainable with steam power. For example, with a steam plant, boilers, and a stack would be needed, with the added cost of buildings to house the boilers. With the gas engine plant as installed, and operating on gas purchased (as needed) from the local gas company. only the combined engine and mimti room is necessary, and hence we have the following saving in favor of the gas plant as installed over a similar plant steam-operated, and including boilers, stack, etc.:

FIG. 3. INTERIOR VIEW, SECOND POWER STATION.FIG. 2. SECOND POWER STATION, HIGH PRESSURE SYSTEM, PHILADELPHIA.

It is also interesting to note that the repairs on this plant since its installation have been so slight that the cost of same has been practically negligible. A similar installation to the foregoing has been installed at Coney Island. New York. Here the equipment consists of three 175 horsepower Nash gas engines geared to Gould triplex pumps. This equipment has shown equally high economy of operation and reliability as compared to the larger fire service equipment at Philadelphia, all due to the fact that it is only called upon to deliver the water against 150 pounds pressure (Philadelphia plant is 300 pounds). The amount of water is corespondingly increased per bourse power, each engine and pump having a capacity of 3,600,000 gallons. From the results obtained by the two foregoing installations it will be seen that gas engines have special features of advantage for the handling of high pressure pumping service, and that after several years’ trial they have proven entirely satisfactory from a standpoint of reliability as well as economy.

We will next consider the water works field, where the plants are designed to be in cintinuous service 24 hours per day. In this field we find tnat the installation cost of the gasdriven plant is more than that of the steam (including as it should gas-producers), and yet, while the large gas engine-driven pump is in its infancy, unless we include centrifugal pumps, which have so far met with hut slight consideration for this class of work, we therefore find that unless towns are willing to put in a large number of comparatively small units (say 300 Horsepower each) and to pay the very much greater installation cost on the small units, that steam pumps still hold the field for cities, the interest on such added investment and the increase in labor consequent on the nuipber of units to a large degree offsetting the operating fuel economy. It is, however, only a question of time when even this field will he won by gas power, as we shall shortly find on the market the direct-acting gas water pump, which requires no engine, being in itself both engine and pump, and which combine with extreme low installation cost a practical absence of attendance, as the only moving parts about the pump are the check valves for admission of gas and water. A brief description of this novel device may he of interest, but it is impossible to give much data on the subject, for the pump is not yet on the market. The “direct-acting’’ gaswater pump is claimed as the separate invention of several different inventors, the merits of the ownership being, however, without the scope of this article. Suffice to say that it is at this time usually known as the “Humphrey” pump.

FIG. 4. THE GRAND POINT, MANCHESTER, MASS., PUMPING PLANT.

In this device the entering column of water is used to compress a charge of gas in what might be termed the cylinder-head of the machine. The rising column of water trips an ignited mechanism, which explodes the charge directly on the surface of the water, forcing same downward into cine leg of a U-shaped cylinder. As the water descends in one side of this “U’’ it correspondingly rises in the other side, part escaping through the outlet check valve and the balance flowing hack again and by its momentum compressing the fresh charge of gas. means being supirhed tn admit additional water to the pump at each “stroke” to offset that discharged, and also to supply fresh gas fuel and to allow the exhaust gases to escape. Although this pump can hardly be said to be in commercial shape at present, it is rapidly becoming so, and the following record of a’ test made under conditions that vouch for the accuracy of the record will go to show that when this type of pump is fully developed it will, on account of its extreme efficiency and utter absence of wear and tear, revolutionize heavy duty pumping.

FIG. 5. PLANT AT SPRINGFIELD, OHIO.FIG. 6. PLANT AT FORD CITY, PA.

With a lift of 39.4 feet, the compression pressure was 56.5 pounds; the resulting explosion pressure was ItM pounds, with a maximum cushion pressure of 1S5 pounds, and one complete cycle took 4.92 seconds. It is figured that with a compression pressure of 11 atmospheres the over-all theoretical efficiency would he 52.5 per cent. This pump strongly resembles the wellknown water “ram.” the chief difference being that the impulse is supplied by the explosion of the contained gas charge.