The effect of sediment on the running characteristics of the water pump

The Yellow River water contains more sediment, which has a great impact on the characteristics of the centrifugal pump. Due to hydraulic wear and mechanical wear, the flow rate, lift, and efficiency are reduced, and the characteristic curve of the pump is different when the power increases. It can be seen from the performance curve after the influence of sediment that the larger the sediment content, the lower the pump efficiency, the smaller the flow rate, the corresponding reduction in lift and the corresponding increase in power.

Generally speaking, the cause of wear is the scouring and abrasive force generated by high-speed sand-laden water flow. When the sediment with a certain particle size and hardness passes through the water pump at a high speed, a considerable abrasive force will be generated, and the fine particles on the metal surface will be peeled off layer by layer, causing surface damage. Therefore, high speed is the main cause of water pump wear. The high-speed sand-laden water flow forms vortices and bends on the uneven surface of the metal, and the sand particles repeatedly impact the surface to destroy the wall.

Due to the impact of the edges and corners of the sand grains, the pressure per unit area is very large, which exceeds the ultimate strength of the metal surface and is damaged, especially the eddy current and the backflow part, this effect is particularly obvious. For example, the wear of the blades, both sides of the impeller disk, the mouth ring, the pump casing, etc. is mainly caused by the eddy current and the backflow impact. Due to the above two effects, the former wears to form streaks, the latter forms pits, and the combined effect of the two forms fish-scale grooves. Therefore, the wear and tear of sediment seriously reduces the service life of the pump. Measures to prevent water pump wear: Improve the wear resistance of water pump components. According to relevant tests, the order of metal wear resistance is: stainless steel, nickel-chromium steel, ordinary steel, brass, and cast iron. Among them, cast iron has poor wear resistance, mainly due to structural characteristics. Inhomogeneity and damage are gradually exfoliated from the graphite component in the cast iron. Now, the pump parts we use are cast iron, so they can't withstand the abrasion of sediment.