Analysis of the reasons for the decrease of pump efficiency

1. Due to the scouring of the water flow, the inner wall of the pump channel and the impeller water surface become rough and uneven, the friction coefficient of the inner channel of the pump increases, and the flow velocity of water in the pump is large, which increases the head loss. The hydraulic efficiency decreases.

2. Due to the addition of drugs or water quality in front of the pump, serious scaling or corrosion occurs in the pump casing. Serious scaling in the pump casing can increase the wall thickness of the pump casing by about 2ram, and form scale nodules on the inner wall of the pump, reducing the volume of the pump, reducing the pumping capacity, roughening the flow channel, and increasing the head loss. Both the guest volume efficiency and the hydraulic efficiency decrease.

3. Due to casting defects, cavitation, abrasion, corrosion, chemical etching and other reasons caused by the processing technology of the pump, cavities or cracks are generated in the pump channel, and vortices are generated when the water flows, resulting in energy loss. The hydraulic efficiency decreases.

4. Cavitation on the impeller surface. Since the negative pressure is generated when the blade is running on the back water surface, when the pressure PK < PVA, cavitation and honeycomb surface will occur, which will cause cavitation of the pump blade under the action of electrochemical corrosion.

5. Volume loss and mechanical loss. As the pump is used for a long time, leakage and resistance caused by mechanical wear increase, which reduces volumetric efficiency and mechanical efficiency.

For the above reasons, the performance of the water pump deteriorates. The operating efficiency can be reduced by 2-5%, and the pump efficiency can be reduced by more than 10% in severe cases.