4.28 Two Bell & Gossett Series 80-SC 3 3 7B pumps with 5-in. impellers are...

4.28 Two Bell & Gossett Series 80-SC 3 × 3 × 7B pumps with 5½-in. impellers are connected together in parallel. Both pumps are operating at 3525 rpm. This parallel pump combination is connected to a pipe system that has an elevation difference (outlet to inlet) of 40 ft. At a flow rate of 500 gpm, the head in the system is known to be 100 ft.

a. Plot a pump performance curve that shows the performance of each individual pump and the performance of both pumps operating in parallel.

b. Overlay the system curve on the plot you developed for part

(a) and determine the operating point of this parallel pump/pipe system (head and capacity).

c. What is the operating point of each individual pump (head and capacity)

when they are both operating in parallel? What is the efficiency and power draw of each pump under this condition?

d. If one of the pumps fails, determine the operating point (head and capacity)

along with the efficiency and power draw of the remaining operational pump.