78 SMALL WATER SUPPLIES. 



altogether. Some form of retaining, or foot valve, 

 should also be included in the equipment, in order 

 that the pump will never "suck wind," as it is 

 termed. For ram pumps of all kinds, except high- 

 speed pumps, to which reference will be made, the 

 simplest and best form of valve is the mitre valve, as 

 shown in fig. 60, made of gun- 

 metal and having gun-metal seats 

 fixed in the pump casing. They 

 are usually bevelled to an angle 

 of 45 and fitted with feathers to 

 stop and guide the beat of the 

 valve. They should be made as 

 FIG. 60. large as possible, in order to reduce 



the amount of lift required and consequent wear. 



Another class of pump having solid buckets is 

 shown in fig. 61. In detail it is not so much used 

 as those previously mentioned, but gives a very even 

 flow of water. They want more attention than the 

 other types, and consequently this will only render 

 their use in large, shallow wells admissible. 



The rings are a patent composition known as 

 Woodite and are shown at A in fig. 61 A. The 

 bucket is solid, and in order to fit the rings they 

 must be heated in hot water for 15 minutes, and 

 stretched over the bucket, which is then placed in 

 position in the pump barrel. At B are shown holes 

 T V in. in diameter. There are four to each ring. They 

 serve to admit the water behind the rings to keep 

 them tight. At C should be a working clearance 

 between barrel and bucket. 



We now pass on to a class of pump used in con- 



