PUMPING MACHINERY 



273 



may be placed in wells of small diameter. This class of 

 pump gives but little suction and works the best when 

 immersed in the water. 



388. The hydraulic ram. Where a fall of water of 

 sufficient head and volume is at hand, it may be used to 

 elevate a portion of the flow of water to a higher eleva- 

 tion. The action of a hydraulic ram depends upon the 

 intermittent flow of a stream of water whose momentum 

 when brought to rest is used in forcing a smaller stream 

 to higher elevation. The ram consists essentially of 

 (a) a drive pipe leading the water from an elevated source 

 to the ram ; (b) a valve which automatically shuts off the 

 flow of water from the drive pipe through the overflow, 

 after sufficient momentum has been gathered by the 

 water ; (c) an air chamber in which air is compressed by 

 the moving water in the drive pipe in coming to rest; 

 and (d) a discharge pipe of smaller diameter leading to 

 the elevated reservoir. 



TABLE OF PROPORTIONATE HEAD, GIVING HIGHEST EFFICIENCY IN 

 OPERATION OF HYDRAULIC RAM* 



Under the foregoing conditions about 12 times as much 

 water will be required to operate ram as will be dis- 

 charged. 



Hydraulic rams are manufactured in sizes to discharge 

 from I to 60 gallons a minute, and for larger capacities 



* The Gould Company, Chicago. 



