TESTS OF DRAINAGE PUMPING PLANTS. 21 
TEST OF PUMPING PLANT IN JEFFERSON DRAINAGE DISTRICT NO. 3, LAFITTE, LA. 
DESCRIPTION OF PLANT. 
This pumping plant is used to drain a tract of about 5,000 acres. 
The average lift of the pumps is about 4 feet, and at times the 
maximum lift is 10 feet. 
It consists of two 48-inch double-suction centrifugal drainage 
pumps direct-connected to two 16 by 36 inch simple noncondensing 
Corliss engines of the girder-frame type. The engines are fitted with 
gravity release gear and a special governor for emergency use in case 
the pumps lose their priming. The cut-off is adjustable by hand while 
the engine is running. Steam is furnished to the engines by two 
Brownwell horizontal return tubular boilers of 150 horsepower each. 
The fuel used is Mexican crude oil. For starting the boilers with oil, 
steam is supplied by a 10-horsepower boiler fired with wood or coal. 
The suction and discharge pipes are respectively 25 feet and 20 feet 
long and are enlarged so that the areas of the intake and discharge are 
four times the area of the discharge nozzle of the pump. The 
suction pipes are tapered uniformly from one end to the other, while 
the discharge pipes are tapered and flattened so that the outer ends 
have a rectangualr cross section with the sides rounded to a radius 
of 24 inches. A steam ejector is installed on each pump for use in 
expelling the air in priming. 
While this plant was guaranteed to deliver at normal load 55,000 
gallons per minute against a total head of 6 feet at a speed of 100 
revolutions per minute, it was decided to test it at a much lower 
total head and somewhat greater capacity and speed. 
FIRST TEST. 
The first test of this plant determined the capacity and efficiency 
of the pumps for a rather wide range of heads and speeds. During 
the test the head increased rapidly, making it necessary to take 
observations on the pumps as frequently as possible. It was decided 
that a boiler-test run under such varying conditions would be of 
little value. 
Tests were run on each unit separately. In making the tests indi- 
cator cards were taken, the speeds of the engines and pumps were 
recorded, a Pitot tube traverse was made in each suction pipe, the 
suction and discharge canal gages were read, and the dynamic head 
was obtained by means of mercury manometers connected to each 
suction pipe near the pump flange and to the discharge pipe near the 
discharge flange. 
At the beginning of the test of unit No. 2 the difference in water 
levels was 3.38 feet. This difference rapidly increased to 6 feet, at 
which point the attempt was nrade to keep the speed of the pump as 
