WATER SUPPLY, PLUMBHsTG, ETC., FOR COUNTRY HOMES. 27 



into the air chamber. (See fig. 22.) The water then rebounds back 

 up the drive pipe until forced down again by the weight of the water 

 in the drive pipe, and the operation is repeated. During each momen- 

 tary reflow a small quantity of water is forced into the air chamber, 

 compressing the air. The resulting air pressure forces water up the 

 delivery pipe to the point of delivery. The operation of a ram is 

 continuous, once started, until the valves become worn. The ordi- 

 nary small ram completes its cycle about 60 times a minute, the length 

 of stroke of the dash valve governing the number of pulsations per 

 minute. 



The length of drive pipe is most important and is governed by the 

 ratio of the fall to the elevation. If too long or too short the auto- 

 matic supply of air is interfered with and the efficiency impaired. 

 The length of drive pipe is usually about 7 times the height of fall 

 although this may vary between 5 and 10, depending on the height 

 and distance to which water is to be delivered. The diameter of the 

 drive pipe is usually twice that of the discharge pipe. 



PUfir ymr£^/f suppvr 



BQ£>r P/PS 



Fig. 24. — Double acting hydraulic ram, showing method of using a turbid creek supply to pump clear 



spring water. 



The proper size of ram to suit certain conditions depends on the 

 following: (1) The flow of water from the source of supply, deter- 

 mined by the time necessary to fill a vessel of known capacity or by 

 weir measurement ; (2) the difference between the level of the supply 

 and the lowest point within a reasonable distance for the location of 

 the ram; (3) the distance between the source of supply and the pro- 

 posed location of the ram ; (4) the difference in level between the ram 

 location and the highest point to which water is to be delivered; (5) 

 length of pipe necessary to conduct the water to the point of delivery. 

 In purchasing a ram this information should be sent to manufac- 

 turers. 



Sometimes a double-acting ram is installed where there is a spring 

 too smaU to operate a single-acting ram but located near a brook from 

 which an ample supply and fall can be obtained to operate the ram. 

 These are so constructed that if properly installed under a fall of at 

 least 2 feet below the spring and 3 feet below the brook it is impossi- 

 ble to deliver anything but the spring water. Figure 24 illustrates 



