WE have on more than one occasion sought to provoke an interest among water-works officials concerning the development of hydraulic power by the application of machinery in connection with the general plan of water distribution. It is known by experience in several cities that the methods adopted were only partially successful and quite limited, owing to the fact that the energy evolved from the pressure ordinarily found in water-works distribution was unequal to meet the requirements of the power necessary to produce a satisfactory result. With these developments of deficiencies due to limited and low pressure has followed the introduction of expensive machinery, using large quantities of water. This form of practice manifestly interfered with the general plan of distribution, owing to the fact that large service pipes were necessary to operate hydraulic machinery, and whatever measure of dynamic energy was thus obtained and used created a corresponding deficiency in the plan of distribution. From fifty to seventy pounds might be termed the range of pressures in water-works practice.
We give the following illustration of what took place in a city not ioo miles from New York :
Six hundred feet 6-inch water main.
Sixty j4-inch taps inserted in the same, each two driven 20 feet apart on opposite sides of the pipe, and two 4-inch connections supplying hydraulic motors. Average pressure at level of street 60 pounds per square inch.
Six-inch pipe, cross section of area in inches, 28.28.
Sixty J^-inch taps, aggregate cross section of area in inches, 1178.
Two 4-inch pipes, cross section of area in inches, 25.
There was no trouble in operating the hydraulic motors. It is quite apparent that when in operation little was left as a margin for tap supply when critically considered. Such a condition of affairs cannot well be maintained in good form for supplying hydraulic power and general service distribution jointly. The result in this case was the erection of small reservoirs on the premises, which at night obtained a supply of water for use in the upper stories, and when the hydraulic motors were not in use. It would appear from these facts that a dual system could not well be maintained to any reasonable extent. Of course in all general plans of distribution, it is possible to utilize a portion of the pressure for hydraulic power, but it must be kept within certain limit, in order not to imperil or impair the system of distribution. We may qualify this allowance by referring to private sewing machine motors and others, that when connected to local distribution, does not interfere or affect general distribution.
Our English cousins are in advance of us with respect to the adoption of hydraulic power. It was inaugurated about ten years ago in London by a private corporation. The system prevailing is separate and distinct from any of the water-works of the city, comprising four pumping stations located on the Thames and distributing a constant pressure of water 700 pounds to the square inch, through twenty-seven miles of pipe. The Birmingham Hydraulic Power Company have recently completed their works. Their plan is different from the one in London, in that they draw their water from the Birmingham system of distribution, which only affects it, if at all, in the proportion of water that may be taken for power purposes. The operation of the pumps and accumulators are in no way identified with the general distribution, being, as it were, eliminated by the use of check valves and other devices designed for the purpose. The developing processes and use of water for hydraulic power is the result of experience, no doubt, similar to what we have herein illustrated, and has led to the adoption of separate systems in the cities of England. It is manifestly the only practical and safe method to adopt in order to obtain effective hydraulic power for distribution and equal to all of the requirements demanded. An effective pressure of 700 pounds per square inch is an enormous advantage considered commercially. Hydraulic engines constructed to operate under 700 pounds pressure, and respectively seventy pounds pressure per square inch, are vastly different in structural characteristics. A twelve-inch piston of a hydraulic engine with a pressure of 70 pounds per square inch, indicates an aggregate pressure of (113 x 70)—9910 pounds of energy multiplied by the number of strokes per minute of the piston, as against a 4j^-inch piston, the area of which is 14.18 x 700 pounds, equals 9926 pounds of energy multiplied by an increased number of strokes per minute of the piston. The increased number of’strokes per minute being in the ratio of the velocity due to 700 pounds pressure compared to the velocity due to 70 pounds pressure. Herein lies the immense advantage in the use of hydraulic power appliances operated under high pressures, thereby dispensing with heavy, cumbersome and very expensive machinery, and using comparatively small, inexpensive and high speed engines geared to run within the maximum figure of safety, doing the work with a small amount of water associated with a high degree of pressure. The details of construction are such as to govern the factor of a constant pressure necessary and requisite to meet every emergency. Any number of hydraulic engines can be run as may be required, and by simple mechanical automatic devices are thus controlled.
The Birmingham plant use gas engines in order to obtain initial power. This, to us, is a novel innovation and leads us to conclude that gas combustion must be cheaper than that of coal. We know that gas for power purposes is among the probabilities as a substitute for coal, considered as a commercial advantage. We hope for a development of this character in this country. It is the province of the American capitalist to survey this new field of investment, and it is quite time that here in New York city, steps should be taken to inaugurate a hydraulic power plant. Abundant opportunity exists for the development of it. There is no reason why New York city should not be skirted OP each of its river sides with a hydraulic power watei main, operated by the accumulative system in part and by water power when sources alone would contribute at least a considerable portion of dynamic energy necessary to a practical solution of the question.
A MAN with a keen technical knowledge and a deep yearning to acquaint the world of it philosophises after the following manner in the editorial columns of The Harrisburg (Pa.) Independent:
A great many people who, perhaps, do not comprehend the policy of selling water by measure, cannot understand wherein the water meter is a benefit to the city, especially when it is a fact that it costs as much, in the way of interest on the water debt, employees, etc., to pump a half million gallons as it does to raise a million gallons into the city reservoir, the only saving being in fuel. A man who has a water meter in his premises, will supply his stable containing several horses and his dwelling containing six to ten persons with all the water needed tor less money than does a man who has no stable, no horses and only three or four persons in his home. Under such a system who is benefited ? The answer Is plain, namely, only the large consumer of water and the manufacturer who sells the meters, while the large majority of water consumers and the city which erected an extensive system to supply its inhabitants with water arc heavily burdened. The water meters should only have been introduced into factories and other industrial institutions, or where it is used as a motive power, ami not into private reddeuces. Eventually this will have to be the case, or the rates for water as measured by the meters must be increased to meet the interest on the water debt, and the expenses of a vast waterworks as well as to deal impartially with all private consumers.
One fact this young man appears to have overlooked is that it costs money to pump water and if, as stated, the cost of pumping one million gallons is no more than pumping half that amount, except the fuel employed, the factor of wear and tear of machinery and boilers in pumping the additional amount is of no importance whatever. In fact, any amount of water pumped that is wasted is lost, and it is no small figure in the yearly calculation of expenses incident to maintenance account. We do not know what the pumping capacity of the Harrisburg water-works may be. It is well known that lake and river cities, having abundant sources of water supply, have been led into the popular error, peculiar to their location, that the question of waste of water cuts no important figure in any calculation of water supply. The error lies in the fact that cost of pumping water, ot which from thirty-three per cent to fifty per cent is wasted, has not been considered until the city thus enjoying the ad libitum privilege is confronted by the fact that not only more pumping power is required, but increased distributing capacity in water mains andincreased distributing reservoir area is required to meet the demand occasioned by a consumption of water absolutely wasted. The abridgement of waste, in substance, means the restoration of the power of the water-works, and practically a duplication Qf a water supply equal in all respects to the amount of the cost of the water hitherto wasted. Water meters simply, effectively and permanently stop waste of water. No other device will do it as well and as satisfactory.