TESTS OF DBAINAGE PUMPIXG PLANTS. 5 



charge velocities one-fourth as great as with pipe of uniform size. 

 Losses vary as the square of the velocity, so they will be reduced to 

 one-sixteenth of the loss in a pipe of uniform size, if the diameter 

 of the ends of suction and discharge pipes be gradually enlarged to 

 twice the diameter of the rest of the pipe, or, in case the pipe is not 

 round, if the end area be increased four times. 



The importance of this matter of pipe expansion is illustrated by 

 figure 1. It is assumed that the pump flange is designed for a dis- 

 charge pipe 2 feet in diameter and that the mean velocity is 10 feet 

 per second. The length of straight pipe is taken as 15 feet. 



SOURCES OF POWER FOR PUMPING PLANTS. 



STEAM ENGINES. 



Steam engines were used to furnish power for the earliest pumping 

 plants. The simpler and less efficient types first employed have 

 been replaced by more efficient types as improved pumps have 

 taken the place of the drainage wheel and less efficient pumps. 

 Plants now in use employ simple, noncondensing engines, compound 

 condensing engines with high-pressure water-tube boilers, Corliss 

 engines direct-connected to centrifugal pumps, and one plant in- 

 spected used superheated steam in a compound-condensing engine 

 of the poppet-valve type. Steam plants of all types are reliable in 

 operation, and when the pumps are of the centrifugal type the 

 capacity may be increased to a marked degree, at the expense of 

 efficiency, by merely increasing the speed. Steam plants are easily 

 run and if cared for by a competent operator will have a reasonable 

 length of life. 



Unfortunately, however, they frequently do not receive the neces- 

 sary care. The principal cause of deterioration is the character of 

 water- that is used in the boilers. Generally the only water available 

 is the drainags water from the wet prairies, containing acids and 

 organic compounds which corrode and cause trouble with feed pipes, 

 boiler accessories, and boilers. 



Besides the boiler troubles to which they are liable steam plants 

 are often wasteful <>i' fuel, while the opposite is true of plants using 

 the internal-combustion engine. For these and other reasons the 

 mosl recenl pumping plants erected in Louisiana have in many 

 instances used internal-combustion engines as a source of power. 



INTERNAL-COMBUSTION ENGINES. 



In the hi-t few vears the i n I ernal-eomhllsl ion engine has hceli so 



far improved and perfected thai lack of reliability is no longer con 

 sidered ;i hindrance to its use. For several years four-stroke cycle 

 engines were used almosl exclusively, and the fuels employed varied 

 from heavj low-grade crude oil-, to kerosene. Recently, two stroke 



