Which term describes the measure of the work increase imparted to the liquid by the pump, equal to the algebraic difference between the total discharge head and the total suction head?

• A. Total Head (H), Horizontal Pumps
• B. Total Discharge Head
• C. Net Head
• D. Suction Head

Answer: (A)

The concept being tested is the head added by the pump—the energy the pump contributes to the fluid. This is found by taking the algebraic difference between what the fluid has at the discharge and what it has at the suction. That difference represents the work imparted to the liquid by the pump, i.e., the head added by the pump.

In practical terms, the discharge head and suction head each include elevation, pressure, and velocity components. The pump increases the liquid’s energy, so the head added is the difference between those two heads. If the discharge head is higher than the suction head, the pump contributes a positive amount of head equal to that difference.

Total head describes the overall energy level at a point in the system, not specifically the energy added by the pump. That’s why the term Net Head is the correct description of the pump’s work on the liquid. For example, with a discharge head of 120 ft and a suction head of 40 ft, the pump adds 80 ft of head.