TESTS OF DRAINAGE PUMPING PLANTS. 



29 



TEST OF PUMPING PLANT IN SUBDISTRICT NO. 4, JEFFERSON DRAINAGE DISTRICT 

 NO. 4, JEFFERSON PARISH, LA. 



DESCRIPTION OF PLANT. 



In Plate I are shown interior and exterior views of this plant, and 

 figure 3 is a cross-sectional view showing the shape of the suc- 

 tion and discharge pipes and method of supporting the plant. 

 The pumping equipment consists of two duplicate units, each with 

 a capacity of 59 cubic feet per second at a 2-foot lift and capable of 

 pumping at any head between zero and 10 feet, the capacity decreas- 

 ing as the head increases. The pumps are 30-inch, double-suction, 

 slow-speed drainage centrifugals with special radial and axial flow 

 impellers having a nearly constant horsepower input at all heads. 

 They are direct-connected through friction-clutch couplings to 

 60-horsepower distillate engines designed to make 190 revolutions 

 per minute and operating on cheap distillate of 39° Baume gravity. 



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Fig. 3.— Elevation of pumping, subdistrict No. 4, Jefferson drainage district No. 4. 



The engines are started on gasoline, run for a few minutes until the 

 jackets warm up, and are then switched to distillate by throwing 

 the handle of a six-way cock. Batteries are unnecessary, as the 

 engines are fitted with oscillating magnetos suitable for starting as 

 well as running, a valuable feature for an isolated plant. Cooling 

 water is supplied by two rotary pumps belted off the hub of the 

 clutch coupling, one to each unit. Each of these pumps is of ample 

 size to supply water to both main engines and to the water-sealed 

 glands of the main pumps. To insure a supply of water for starting 

 and to provide against accidents to the circulating pumps, a 500- 



gallon elevated tank was creeled. This furnished ;in hour's supply 



for one engine and is so piped that should the pump stop working, 

 water would still flow to the jackets. An added advantage of this 

 arrangement is that it gives n constant head of water on the jackel 

 at all times. 



