Plumbing 



215 



ordinary pump is not sufficiently tight to produce a perfect vacuum, therefore 

 the height to which the water may actually be raised is somewhat below this. It is 

 generally considered to be 25 feet. 



The working of an ordinary suction pump is shown in Fig. 36. The 

 plunger (b), fitting snugly into the cylinder (d), is moved up and down by 

 means of the attached plunger rod and pump handle. By lowering the plunger the 

 air in the cylinder below it is forced out through the plunger valve (c). The 

 valve (a) remains closed in inaction, and also against downward pressure, opening 

 only to pressure from below. By raising the plunger the tendency is to form a 

 vacuum. The air pressing upon the top of the plunger finds no access to the 

 space below, but that pressing on the top of the water in the well forces a quantity 

 of water into the suction pipe to replace the air drawn out of it into the lower part 

 of the cylinder. By the successive up-and-down thrusts of the plunger the air is 

 exhausted from the suction pipe and the water, forced after it by the pressure of the 

 outside atmosphere, 



is finally ejected Vl^ 



through the plunger 

 valve (c), and thus 

 through the pump 

 spout as it rises 

 higher in the cyl- 

 inder. 



Thus it appears 

 that this type of 

 pump at first draws 

 air and, having ex- 

 hausted the air by 

 suction, then draws 

 water. If the work- 

 ing parts could be 

 made perfectly tight, 

 the amount of water 

 raised at each full 

 stroke would equal 

 the cubic space in 

 the cylinder below 



the plunger when that member is raised to the full height of stroke. This amount 

 of cubic space, less the amount of water actually raised each full stroke, shows the 

 amount of leakage. 



The lift pump, like the foregoing, follows the same general principle, which 

 is the same in all pumps. Its notable difference is in the location of the cylinder, 

 which is submerged in the water at the end of the pump pipe. There is no air 

 below the plunger to exclude, and hence the water is lifted by successive strokes 

 through the pump pipe in the manner already described. Of the two, this type 

 is the better working, owing to the parts being tighter, submerged as they con- 

 stantly are, but it is more expensive and harder to get at in case of accident than 



Portion of a bathroom showing a simple and tasty tile wainscotting 



