FARM SANITATION 



489 



lined cylinders are used where the water contains elements 

 that corrode iron and brass. 



Plungers are constructed to suit the lift under which they 

 are to work. If the lift has but a few feet, one plunger 

 leather which expands out toward the cylinder walls, making 

 a water-tight fit, will be sufficient; but if the well is deep or 

 the water is to be lifted against pressure, as many as four 

 leathers will be found best. 



Fig. 303. Some common types of pump cylinders. 1 is of plain cast 

 iron, 2 is galvanized, 3 is porcelain lined, 4 and 5 are brass lined, and 

 6 is an all-brass cylinder. 



The valves are another important part of a pump. 

 They should be designed to resist wear and to require the 

 minimum of attention. There are at least four types of 

 valves used in farm pumps. The hinge valve, made with a 

 metal weight on a leather disk and attached at one side, is 

 used where the lift is not great. It is a simple valve and the 

 cheapest, but is not well suited for high pressures. Poppet 

 valves are those which lift directly from the seat, and are 

 made with one or three prongs to guide the valve to its seat. 

 These valves are the easiest to repair. Ball valves are used 



