WATER SUPPLY, PLUMBING, ETC., FOR COUNTRY HOMES. 19 



Pipe friction should be included in computing the pumping height, 

 as discussed under "Pumping." 



THE AUTOPNEUMATIC SYSTEM. 



Cioseo 



In the autopneumatic system the water is deUvered fresh from the 

 well to the faucets. This system consists essentially of an air com- 

 pressor driven by a small gas engine or electric motor, an air-tight 

 steel air-pressure tank;, and one or more autopneumatic pumps. No 

 water tank is required, since nothing is stored but compressed air. 

 The pump consists of two small metallic chambers submerged in the 

 water, and when a faucet is opened they automatically fill and dis- 

 charge, owing to the 

 au' pressure from the 

 storage tank, thus 

 giving a continuous 

 flow of fresh water. 



Figure 16 illus- 

 trates the principle 

 of operation of the 

 pump. Suppose a 

 small air-tight tank 

 A with inlet valve 

 is submerged in 

 water and allowed to 

 fill. A discharge pipe 

 5 is connected at 

 the bottom leading 

 upward to faucet 

 K. Compressed 

 air is forced through 

 pipe G into the 

 top of the tank so 

 that the water is 

 forced out through 

 the discharge pipe until the tank is emptied of water. A similar 

 tank D is connected as shown. The pump has a device for auto- 

 matically opening and closing the air valves and exhaust valves to the 

 tanks alternately. While A is emptying of water T> is filling, and 

 they discharge alternately. 



Figure VIA gives a front and side view of an autopneumatic pump 

 and figure 17.5 shows the entire working parts of a system and also 

 how the pump may be used in bored and cased wells. 



Each pump requires an air-pressure reducer, shut-off and release 

 cocks, pressure gauge, etc. The air-pressure reducer is necessary to 

 reduce the high pressure carried in the tank to the uniform low pres- 

 sure required to operate the pump. It is placed in the air-pipe line. 



Fig. 16. — Principle of operation of an autopneumatic pump. 



