Water at $20^{\circ} \mathrm{C}$ is pumped at a rate of $300 \mathrm{gpm}$ from an open well in which the water level is $100 \mathrm{ft}$ below ground level into a storage tank that is $80 \mathrm{ft}$ above ground. The piping system contains $700 \mathrm{ft}$ of $3 \frac{1}{2} \mathrm{in}$ in. sch 40 pipe, eight threaded elbows, two globe valves, and two gate valves. The vapor pressure of the water is $17.5 \mathrm{mmHg}$.

(a) What pump head and hydraulic horsepower are required?

(b) Would a pump whose characteristics are similar to those shown in Figure 8.2 be suitable for this job? If so, what impeller diameter, motor speed, and motor horsepower should be used?

(c) What is the maximum distance above the surface of the water in the well at which the pump can be located and still operate properly?

Figure 8.2

Transcribed Image Text:

Size 2 3 R & C 1% in. Pedestal 3500 rpm 4' minimum NPSH 400 Impeller dia. 300 200 8% in 8% in 7% in 7% in 6% in. 6% in. I Total head feet 100 50 MISSION VALVE AND PUMP COM Semi-open impeller Dia. 6%-8% in. Eye area 9.8 in. Curve 8 S1 20 ft Max. sphere 1% in. Maximum normal capacity for slurries and abrasive fluids 7ft 30% 10ft. 140% 15 ft 145% 50% 50 50 40HP 15 HP 20 HP 30 HP1 25 HP 25ft, 50% 45% 60 HP 50 HP 400 40% 500 600 700 Capacity-U.S. gallons per minute 100 200 300