A circulating pump takes hot water at 858C from a storage tank, circulates it through a piping system at a rate of 150 gpm, and discharges it to the atmosphere. The tank is at atmospheric pressure,...

A circulating pump takes hot water at 858C from a storage tank, circulates it through a piping system at a rate of 150 gpm, and discharges it to the atmosphere. The tank is at atmospheric pressure, and the water level in the tank is 20 ft above the pump. The piping consists of 500 ft of 2 in. sch 40 pipe, with one globe valve upstream of the pump and three globe valves and eight threaded elbows downstream of the pump. If the pump has the characteristics shown in Fig. 8-2, determine

(a) The head that the pump must deliver, the best impeller diameter to use with the pump, the pump efficiency and NPSH at the operating point, and the motor horsepower required to drive the pump.

(b) How far the pump can be located from the tank without cavitating. Properties of water at 858C: Viscosity 0.334 cP, density 0.970 g/cm3 , vapor pressure 433.6 mmHg.