Centrifugal pump surge refers to the phenomenon of the pump wheezing during the process of conveying the medium fluid. The liquid medium flows out intermittently, which causes the pump discharge pressure and flow to vibrate periodically and makes the pump run unstable.

      Analysis on the Cause of Surge of Centrifugal Pump

       1. The automatic exhaust valve of the water pump fails to discharge the air in the pump in time;

       2. The inlet flow channel of the water pump is too small, which causes the flow rate at the inlet of the water pump to be too large, so that a vortex phenomenon occurs at the inlet of the water pump;

       3. Local roughness is too large at the inlet of the pump impeller;

       4. There are irregular and movable sundries at the inlet pipe of the pump, and the inlet section changes irregularly, which causes the inlet flow rate of the pump to be too high, resulting in cavitation of the pump;

       5. The sealing of the joint of the pump outlet pipe is not good, resulting in insufficient displacement of the pump exhaust valve.

       Surge will cause the pressure and flow in the entire pump system to change. When the pump is cavitated, this phenomenon is called "cavitation surge", even if the lift and flow curves are negative slopes, cavitation surge It also occurs, for example, when there is a hump in the performance curve of a low specific speed centrifugal pump, it may cause surge under unstable conditions.

      Centrifugal pump surge elimination method

       1. Check whether the automatic exhaust valve of the water pump is flexible and reliable;

       2. Solve the problem that vortex is generated at the inlet of the pump due to the small flow of the pump inlet and the excessive inlet flow rate;

       3. Check whether the water pump impeller and casing are damaged;

       4. Check whether there are movable foreign objects at and near the inlet of the pump;

       5. Check whether there is leakage at the joint of the pump outlet pipe;

       6. When starting the water pump, ensure the liquid level at the inlet of the water pump;

       7. When choosing the hump curve, the pump pipeline plan should be fully considered so that the working point of the pump equipment falls in the stable operation area. It is recommended that the pump not work in the unstable small flow area.

       8. The water pump flow control valve should be installed between the water pump and the air tank, not behind them, or the static lift of the pump should not exceed the dead lift of the pump.

      Safety Precautions for Eliminating Surge in Centrifugal Pumps

       1. Take safety measures before the centrifugal pump is overhauled;

       2. During maintenance, turn off the power switch of the water pump and take measures for power failure;

       3. When checking the running water pump, take safety precautions.