488 AGRICULTURAL ENGINEERING 



Pump tests. 



Important Features of a Pump. In selecting a pump, the 

 service to be required of it should always be kept in mind. If 

 the water is only to be lifted from a shallow well and delivered 

 into a pail or tank under the spout, any common lift pump 

 may be used. A lift pump is one in which no provision is 

 made for forcing or lifting the water higher than the pump 

 spout. Force pumps have the pump rod packed, making it 

 water-tight. 



One of the most important parts of a pump is the cylinder, 

 of which there are three common grades on the market; viz., 

 plain iron, iron with brass lining, and brass-body cylinders. 

 The first is the cheapest, but is the least durable, as iron 

 easily corrodes. Brass-lined cylinders are quite satisfactory, 

 in that the iron supports and protects the brass, which is a 

 soft metal. Brass-body cylinders are used where corrosion 

 will be unusually rapid and where space is limited. Often, in 

 drilled wells of small diameter, brass-body cylinders with the 

 caps screwed inside of the barrel instead of on the outside 

 are installed, thus permitting the use of a cylinder of rela- 

 tively large diameter. Brass-body cylinders will not stand 

 severe service. When dented, they are almost past repair, 

 and the screwing of the caps to the thin barrel is difficult, be- 

 cause little material is provided for the threads. Porcelain- 



