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:
“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:
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:
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.