Determine the required horsepower of the pump in Example 19.4 if the presence of one 90° elbow and one wide-open gate valve in the suction line and one wide-open gate valve, one half-open globe valve, and two 90° elbows in the discharge line are included.

Example 19.4

Consider a physical situation similar to that in Example 19.2. The flowrate between tanks is 10 lb/sec. The source-tank level is 10 ft off of the ground, and the discharge-tank level is 50 ft off of the ground. For this example, both tanks are open to the atmosphere. The suction-side pipe is 2-in, schedule-40, commercial steel, and the discharge-side pipe is 1.5-in, schedule-40, commercial steel. The length of the suction line is 25 ft, and the length of the discharge line is 60 ft. The pump efficiency is 75%. Losses due to fittings, expansions, and contractions may be assumed negligible for this problem.

Determine the required horsepower of the pump.

Determine the pressures before and after the pump.

Example 19.2

Water in an open (source or supply) tank is pumped to a second (destination) tank at a rate of 5 lb/sec with the water level in the destination tank 25 ft above the water level in the source tank, and it is assumed that the water level does not change with the flow of water. The destination tank is under a constant 30 psig pressure. The pump efficiency is 75%. Neglect friction.

Determine the required horsepower of the pump.

Determine the pressure increase provided by the pump assuming the suction and discharge lines have the same diameter.