TESTS OF DRAINAGE PUMPING 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been replaced by more efficient types as improved pumps have 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 drainage 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 of fuel, while the opposite is true of plants using 
the internal-combustion engine. For these and other reasons the 
most recent pumping plants erected in Louisiana have in many 
instances used internal-combustion engines as a source of powder. 
INTERNAL-COMBUSTION ENGINES. 
In the last few years the internal-combustion engine has been so 
far improved and perfected that lack of reliability is no longer con- 
sidered a hindrance to its use. For several years four-stroke cycle 
engines were used almost exclusively, and the fuels employed varied 
from heavy low-grade crude oils to kerosene. Recently, two-stroke 
