COST OF WATER l6l 



I. The Piston or Plunger Pump. — The piston or plunger 

 pump is most commonly used in the creamery. Tliis may be 

 belt driven or it may be operated with steam direct. The for- 

 mer method is the most economical providing the pump is large 

 enough, and that a supply tank of sufficient size is provided so 

 that all the pumping is done while the engine is being operated 

 for other purposes. It would not be profitable to operate a 

 large engine merely for the purpose of pumping water. Then 

 it would be more advisable to install a pump driven by steam 

 direct. 



n. The Rotary Pump. — The rotary and the centrifugal 

 pumps may be used for shallow wells. For small hfts of 4 to 

 5 feet they are considered to have a higher efficiency than the 

 piston pumps, but for higher lifts their efficiency is less and they 

 wiU not be practical for lifting water to exceed 15 to 20 

 feet. 



in. The Air Lift. — The air lift consists of a well tubing, 

 inside of it is a small pipe through which compressed air is 

 blown. The compressed air lifts the column of water. By this 

 system water may be lifted 130 feet above its lower level. It is 

 said to be of greatest efficiency when the depth at which the 

 discharge tube stands under water in the well is one and a half 

 times the height of the discharge pipe above the water. By re- 

 ducing the proportion of the pipe below the water surface the 

 efficiency is gradually decreased and the system cannot be 

 operated if the portion above the water is increased to one and a 

 half times the size of the pipe below the water surface. 1 It 

 is claimed ^ that the cost of raising 1,000 gallons of water by the 

 air lift, including fuel, labor, oil, interest on cost of well, boiler, 

 compressor, foundations, pipes, real estate, erection, taxes, and 

 15 per cent for depreciation runs from one-fifth to two and one- 

 half cents according to size of plant, height of lift, and other 

 local conditions. 



' Siebel's Compend. of Mechanical Refrigeration and Engineering, 1911. 

 ' Reported by Kidder in Architects' and Builders' Pocketbook, 1912. 



