How to prevent pump cavitation?
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This post was last edited by yxmqh on 2009-12-2 12:14 My unit has a centrifugal pump, and cavitation often occurs. Please analyze the reasons and deal with them.
(1) Improve the structural design from the suction inlet of the pump to the vicinity of the impeller. Increase flow area ； Increase the curvature radius of the impeller cover inlet section to reduce the rapid acceleration and pressure drop of the liquid flow ； Appropriately reducing the thickness of the blade inlet and rounding the blade inlet to make it close to a streamline shape can also reduce the acceleration and pressure drop around the blade head. ； Improve the surface finish of the impeller and blade inlet to reduce resistance loss ； Extend the blade inlet edge to the impeller inlet to allow the liquid flow to receive work in advance and increase the pressure. (2) Use a front inducer to make the liquid flow work in advance in the front inducer to increase the liquid flow pressure. (3) Use a double-suction impeller to allow the liquid flow to enter the impeller from both sides of the impeller at the same time. The inlet cross-section will be doubled and the inlet flow rate can be doubled. (4) The design working condition adopts a slightly larger forward angle of attack to increase the blade inlet angle, reduce the bending at the blade inlet, reduce blade obstruction, and increase the inlet area. ； Improve working conditions under high flow rates to reduce flow losses. However, the positive angle of attack should not be too large, otherwise it will affect the efficiency. ( (5) Use anti-cavitation materials. Practice shows that the higher the strength, hardness and toughness of the material, the better the chemical stability and the stronger the anti-cavitation performance.
Connect a small storage tank to the inlet of the pump. The inlet is higher than the outlet. Fill up the transport fluid before starting the pump and seal it tightly, which can effectively prevent cavitation.
Dig a pit, install the pump in the pit, and lower the installation height of the pump.
Cavitation occurs in the pump because the necessary cavitation margin increases. The necessary NPSH is related to the blade installation angle, flow rate, flow resistance and tank pressure. You can increase the pressure of the storage tank, fully open the inlet valve, or change the blade installation angle to reduce the necessary NPSH.
If it is high temperature water, the problem will not be so easy to solve.