1, due to water erosion, water pump flow inside impeller surface becomes rough, pump flow friction coefficient increases, coupled with the water inside the pump flow rate is very large, increasing head loss. Hydraulic efficiency.
2, because of dosing drugs in front of pump or water quality or other reasons, made severe fouling or corrosion in the pump casing. Fouling serious within the pump casing can make pump shell wall thickness increase 2ram, and scale formed on the inner wall of water pump, and pump volume to narrow, rough pumping less water, and flow, increase in head loss. Product efficiency and hydraulic efficiency is reduced.
3, due to the pump processing technology of casting defects, cavitation, erosion, corrosion and corrosion cause pumps produce flow in holes or cracks, caused by water flow Vortex energy loss. Hydraulic efficiency.
4, surface of impeller cavitation. Due to back-water run to create negative pressure, when the pressure is at Pk<Pva, steam cave and honeycomb surface, in the presence of electro-chemical corrosion and cavitation of the pump.
5, volume losses and mechanical damage. Because the pumps use a long, mechanical wear and leakage and resistance increases mechanical efficiency volumetric efficiency and reduced.