127 



AC 



The so-called siphon force pump, shown in Fig. 57, is used 

 when the pump is not located over the source of supply, which 

 may be from a well or river or 

 other water-body from 100 to 500 

 feet away. 



Rotary Pumps. In rotary 

 pumps the water is lifted by the 

 suction of two revolving runners 

 with blades rotating in opposite 

 directions within a casing (the 

 rotation being at the rate of 100 

 to 200 revolutions per minute), 

 and forced by the same rotation 

 to desired heights up to about 

 75 feet. Simple forms, lifting 

 15 to 40 gallons a minute, 

 may be had at from #7.50 to 

 $25. 



Centrifugal Pumps. - - These 

 are somewhat similar to the ro- 

 tary types, except there is only 

 a single revolving runner. Inas- 

 much as the single runner will 

 not at the start usually create 



sufficient vacuum to lift the water, this form of pump must first 

 be primed. When the pump is working, the water, lifted by 

 suction, is driven into a discharge pipe leading from the cylinder 

 on a tangent. It is probably better adapted to pumping from 

 trenches or streams than from wells, its great advantage being 

 that sand, stones, and other debris of considerable size will pass 

 through the pump without injuring it. 



Air Lift. -- This is a very efficient system of lifting water and 

 deserves wider use than it now has. The method consists of 

 forcing compressed air through a small pipe inserted within tin- 

 casing. Emerging from the pipe at or near the bottom of the 



FIG. 57. Siphon force pump; I, suction 

 pipe; SV, suction valve; P V, plunger 

 valve; A C, air chamber; C V, check 

 valve; O, outlet or discharge pipe. 



