Centrifugal pump hydraulic loss impact loss, vortex loss and along the friction loss. First, the loss of impact Each pump has its own design flow, when the pump is working under design flow conditions, the inlet flow is along the leaves into the impeller, and therefore does not occur with the impact of leaves, the same outlet flow Also does not happen with the impact of the pump shell, when the efficiency is high. However, when the flow deviates from the design condition, the flow direction of the flow should deviate from the direction of the blade to generate an impact. Impact loss can be expressed as: hch = B (Q-Qk) Â² where: B - coefficient; Q - actual flow; QK - design flow. Second, the vortex loss In the pump, over-current section is a very complex space cross-section, the liquid passed here, the size and direction of the flow rate must continue to change, which will inevitably have a vortex loss. In addition, the flow of the surface there are sharp corners, burrs, stagnant water will increase the vortex loss. Third, the friction along the way due to the pump over-flow surface of the rough and the liquid has a viscosity, so the liquid will have a friction resistance loss flow. The size of the loss is expressed by: hm = AQÂ² where A - coefficient. In all parts of the hydraulic loss, the hydraulic impeller within the largest loss, accounting for about half of the hydraulic loss; followed by the hydraulic turbine guide vane loss, accounting for all hydraulic losses of about 1/4, while the remaining 1/4 Hydraulic loss, loss in the impeller to the guide vane, diffusion guide vanes, anti-guide vane impeller entrance and several other parts. In order to reduce the hydraulic loss of the pump, the flow should be smooth changes in all sections, the size of a reasonable speed. And choose the appropriate impeller, guide vane line and entrance placement angle. In addition, the surface finish of the overcurrent component should also be increased.