WATER SUPPLY FOR COUNTRY HOME 



477 



the plunger? We say it is raised by SUCTION, or that it is 

 SUCKED UP (see Art. 374). 



In the suction-pump, as the plunger is raised there is a 

 tendency to produce a VACUUM just beneath it. The atmos- 

 phere pressing down upon the surface of water in the well 

 forces the water up the run 

 and through the inlet-valve 

 to fill the VACUUM. The 

 work we do, then, in pump- 

 ing with the suction-pump is 

 really expended in lifting the 

 small amount of water in the 

 pump-head already above 

 the plunger and in lifting 

 the atmospheric pressure 

 which is pressing downward 



upon the surface of that water, and not in pulling or drawing 

 the water up the pump-run. Define SUCTION and SUCKING 

 (Art. 374). Explain the process of "sucking" soda water up 

 a straw. 



560. Lift-pump. A LIFT-PUMP is constructed exactly like 

 the head of a suction-pump. Were the head of a suction-pump 

 long enough to reach to the bottom of the well, it would be- 

 come a lift-pump. The inlet valve, then, is at the bottom of 

 the well and the cylinder and plunger are at all times below 

 the surface of the water in the well. The water is therefore 

 lifted and not sucked up. 



561. The Force-pump. It is often necessary to raise 

 water to a level above that of the pump spout. In farmhouses 

 and in dwellings in small towns, where there are no city water 

 works, it is often desirable that water be pumped into a tank 

 in the attic so that sink faucets may be supplied with water 

 under pressure at all times. L T nless some such plan is adopted, 

 modern plumbing conveniences can not be installed in such 

 dwellings; with such a tank, common farmhouses may be 

 equipped with most of the conveniences of city dwellings. 



