1. Due to the scouring of the water flow, the inner wall of the pump flow channel and the impeller passing surface become rough and uneven, and the friction coefficient of the flow channel in the pump increases. In addition, the flow velocity of the water in the pump is very large, and the head loss increases. The hydraulic efficiency is reduced.
2. Due to the dosage of drugs or water quality in front of the pump, the pump casing is seriously fouled or corroded. Severe fouling in the pump casing can increase the wall thickness of the pump casing by about 2 ram, and the formation of scale tumors on the inner wall of the pump, which reduces the volume of the pump body, reduces the pumping capacity, and the flow channel is rough, and the head loss increases. Both customer volume efficiency and hydraulic efficiency are reduced.
3. Due to casting defects, cavitation, abrasion, corrosion and chemical erosion caused by the water pump processing technology, cavities or cracks are formed in the pump flow channel, and vortexes are generated when the water flows, which causes energy loss. The hydraulic efficiency is reduced.
4. Cavitation on the surface of the impeller. Because the negative pressure is generated when the back surface of the blade is running, when the pressure Pk<Pva, the vapor cavity and honeycomb surface are generated, and the pump blade is cavitation under the action of electrochemical corrosion.
5. Volume loss and mechanical loss. As the pump is used for a long time, the leakage and resistance increase due to mechanical wear, which reduces the volumetric efficiency and mechanical efficiency.
The above reasons make the performance of the water pump worse. The operating efficiency is reduced by 2 to 5%, and the pump efficiency can be reduced by more than 10% in serious cases.