Why the efficiency of pump decreased?

1.Due to water erosion, water pump impeller and the inner wall of the flow path through the water became rough, the friction coefficient of the pump flow path increases, and  in the pump flow rate greatly increased and the head of water loss. Hydraulic efficiency.
2.Since the drugs before dosing pump or water quality and other reasons, so that the pump housing severe fouling or corrosion. Severe fouling pump housing can increase the casing wall thickness of about 2ram, dirt and water pump wall to form tumors, so that the pump volume reduced, reducing the amount of pumping, and the flow path coarse, increase head loss. Customer product efficiency and hydraulic efficiency is reduced.
3.Casting defects caused due process pumps, cavitation, erosion, corrosion and chemical attack and other causes produce the pump flow passage holes or cracks, resulting in water flow caused by vortices of energy loss. Hydraulic efficiency.
4.The surface of the impeller cavitation. Due to the dorsal surface of the blade run negative pressure, when the pressure Pk <Pva when, after generating steam hole and cellular surfaces, in the electrochemical corrosion effect, leaves the pump cavitation.
5.The volume loss and mechanical loss. Since the pump using a long time, and resistance to mechanical wear and tear resulting leakage increases, the volumetric efficiency and mechanical efficiency.
For these reasons, the pump performance deteriorates. Operating efficiency is reduced by 2 to 5%, the efficiency of pump can be severely reduced by more than 10%.