PUMPING WATERS. 75 



(d) Badly fitting valves. 



(e) Friction in rising main. 



(/) Bends in the drive pipe causing friction and 

 eddies in the flow. 



The next class of pump which will be considered 

 is the deep well pump. It has already been stated 

 that when the suction of a pump is more than 25 ft. 

 failure to work or impaired efficiency may result. 

 It will sometimes be the case that the water level in 

 in a well may be considerably below 25 ft. from the 

 surface, hence a pump at the surface is impossible 

 and deep well pumps are resorted to. These are 

 usually vertical barrel pumps, although other forms 

 may be used under special circumstances. They are 

 worked by rods actuated by suitable gearing, and 

 driven by some form of motive power or other. 

 Owing to the difficulty of fixing and repair such 

 pumps must be on the very best construction, the 

 bucket, head valves and seating should always be 

 made of the best gun-metal, likewise the stuffing-box 

 glands. It is also an advantage to have the pump 

 barrels lined with gun-metal, but this is only usually 

 found in very large and high-class pumps. The 

 bucket rods should be made of copper, and if the 

 buckets are fitted with gun-metal spring rings there 

 is a decided advantage over the usual methods of 

 leather packing. Single or double barrels are gener- 

 ally used for very large pumps ; three barrels is a 

 great advantage in providing a continuous delivery 

 of water. 



The pump is usually mounted on a strong platform 

 built in the well ; steel beams or cast-iron box 

 girders are very much better than wood, while the 



