EUNNINa WATER FOR FARM BUILDINGS 435 



0X25+8X10+12X10+20X2+10X1 = 400 gallons for a one- 

 day supply. 



3. Selecting the system. — There are two general types of run- 

 ning water systems, viz. : 



a. Gravity system. — In this system the water is pumped into 

 an elevated tank, located higher than the highest faucet, so that 

 the water will flow by gravity. Pumps for this system can be 

 operated by hand, windmill or power, 

 or, where there is running water, an 

 hydraulic ram can be used. 



Where an electric motor is used to 

 operate the pump, an automatic device 

 can be used to start the motor when 

 the tank becomes empty and to stop it 

 when the tank is full. 



b. Pneumatic pressure system. — By 

 this system the water is pumped into 

 an air-tight tank, usually located below 

 the ground to keep the water cool for 

 drinking purposes and free from the 



dust as well as to protect it from freez- 

 ing. The water is forced up to the 

 faucets by the air pressure in the tank. 

 Air, to take off leakage through the 

 w^ater, is pumped into the tank either 

 by a separate air pump or sometimes 

 by an air jDump attachment which fits 

 onto the water pump and which 

 causes it to pump air with the 

 water. Pumps for this system 

 can be operated either by hand 

 or power. 



^\Tiere an electric motor is 

 used to operate the pump, an 

 automatic device can be used which wall start the motor Avhen 

 the minimum pressure is reached and stop it when it reaches 

 the maximum.^ 



4. How is pump to be operated? — Having determined the 

 source of supply and figured the capacity required, it is neces- 



FiG. 217. — Typical pnoumatic pressure 

 system with liaiid (iperated pump. 



* One great advantage of a tank system is its value as a protection against fire. 

 This is a point to be taken carefully into consideration when selecting a system, as 

 it is a great advantage to have water under pressure, such as is afforded by either 

 the elevated or pneumatic tank systems, in case of fire emergencies. 



