28 



BULLETIN 57, U. S. DEPAETMENT OF AGRICULTUEE. 



this method. If this method is preferred, it should be so stated in 

 purchasing. The following table gives approximate sizes of hy- 

 draulic rams to suit certain conditions. 



Sizes of hydraulic rams. 



1 



Dimensions. 



Size of 

 drive 

 pipe. 



Size of 



Quantity 

 per minute 



Least fall 

 recom- 

 mended. 



X umber. 



Height. 



Length. 



Width. 



delivery 

 pipe. 



required 



to operate 



engine. 



1 10 



' 1.5 



20 



25 



30 



40 



Ft. ins. 

 2 2 

 2 2 

 2 5 

 2 5 



2 7 



3 7 



Ft. ins. 



2 10 



3 

 3 3 

 3 4 



3 7 



4 9 



Ft. ins. 

 12 



12 



1 2 

 1 3 

 1 3 

 1 8 



Ins. 



n 



¥ 



4 



Ins. 



1* 



1 



li 



2 



Gallons. 



2- 6 



(i-12 



8-18 



12-28 



20-40 



30-75 



Feet. 

 2 

 2 

 2 

 2 

 2 

 2 



There are four separate problems connected with the hydrauhc ram. 

 These, with practical examples, are described by W. C. Davidson ^ 

 as follows: (1) Given the fall, lift, and quantity of water desired, 

 find the necessary supply at spring. (2) Given the hft, quantity of 

 drive water, and quantity of water desired, find the fall required. 

 (3) Given the fall, lift, and quantity of drive water, find the quantity 

 of water supphed to the storage tank. (4) Given the fall, quantity 

 of drive water, and quantity of water desired', find how high this 

 water can be pumped. 



The computations which follow are based upon an approximate rule, 

 which is stated as follows : Multiply the fall in feet by the quantity of 

 water supphed to the ram in gallons per minute, divide the product 

 by the height the water is to be raised, and the result will be in 

 gallons per minute. Tliis may be expressed in an equation as follows: 



2 = 



}i 



in wliich Q= supply of spring in gallons per minutf\ 



H=i&.\l in feet from spring to ram. ^ = height of storage tank 



above the ram in feet, q = quantity of water pumped in gallons ])er 



minute. The result should be reduced by about one-third to allow 



for friction. 



Example 1. It is desired to find the quantity of drive water in 



the spring necessary to raise 8 gallons per minute to a height of 



60 feet, when the head of drive water on the ram is 8 feet. Sub- 



... ,. . ., ,. ^ JiXq 8XQ0 



stitutmg in the equation Q = -^^ = — ^ — 



60 gallons per minute. 



In tliis case about one-third of the result should be added to allow 

 f(jr fi'iction in pipes, valves, etc., making the necessary drive water 

 supply SO gallons. 



iMissouri Bd. Agr. Mo. Bui., 10 (1912), No. 2. 



