The Mystery of Discharge Pressure and Quantity at Pumping Stations

What can cause the discharge pressure to suddenly increase and the discharge quantity to suddenly decrease at a pumping station equipped with a centrifugal pump?

A) Impeller malfunction

B) Low suction pressure

C) Pump cavitation

D) Valve blockage

Answer:

At a pumping station equipped with a centrifugal pump, the situation where the discharge pressure suddenly increases and the discharge quantity suddenly decreases can be caused by D) Valve blockage. This blockage creates a restriction in the flow path, which leads to a buildup of pressure behind the obstruction. As flow is impeded, the quantity of fluid being discharged from the pump drops significantly.

While impeller malfunction and low suction pressure can affect pump performance, they typically result in a decrease in discharge pressure. Pump cavitation can also decrease discharge pressure as it leads to the formation of vapor bubbles which collapse and can damage the pump over time.

In a pumping station equipped with a centrifugal pump, pump cavitation can cause the discharge pressure to suddenly increase and the discharge quantity to suddenly decrease. Pump cavitation occurs when there is a decrease in the pressure of the fluid being pumped, causing the formation of vapor bubbles. These vapor bubbles then collapse near the pump impeller, causing sudden pressure changes and a decrease in flow rate.