Two pumps are used in series to move a fluid to an elevated storage tank as shown in Figure P4.47. The first pump is a Bell & Gossett Series e-1531 low head, high capacity pump (Model 4AD with a 6.5-inch impeller operating at 1150 rpm).
The second pump is a Bell & Gossett Series e-1531 high head, high capacity pump (Model 2.5BB with an 8-inch impeller operating at 1750 rpm). At a flow of 240 gpm, the system head is 45 ft.

a. Construct a plot showing the individual pump performance curves and the series pump configuration performance (head vs. capacity).

b. Overlay the system curve on the plot developed in part (a) and determine the operating point (capacity and head) of the series pump system.

c. If the Model 4AD pump fails, determine the operating point with the remaining 2.5BB pump (head, capacity, power draw, and efficiency).

d. If the Model 2.5BB pump fails, determine the operating point with the remaining 2.5BB pump (head, capacity, power draw, and efficiency).

Transcribed Image Text:

FIGURE P4.47 Series Bell & Gossett Series e-1531 Model 2.5BB @ 1750 rpm 8-inch impeller High head, high capacity pump Bell & Gossett Series e-1531 Model 4AD@ 1150 rpm 6.5-inch impeller Low head, high capacity pump pump system used to transport a fluid to a large storage tank. 20 ft