When the Liquid ring vacuum pump on the working process , under a certain temperature, when the low pressure of the liquid pressure is lower than the temperature of vaporizing pressure (that is,the saturated vapor pressure), liquid began to boil and bubble, and with the liquid into the high presssure , the bubble burst, quickly fill the fluid surrounding the bubble cavitation, produce a hydraulic impact.This bubble formation, development and rupture of phenomenon is called cavitation.
In the working process of the liquid ring vacuum pump, the suction area of the absolute pressure and pumping system is consistent with the absolute pressure.That is to say, by the pumping system of the higher vacuum degree, and the higher the vacuum degree of suction area.
Liquid ring vacuum pump need fluid as working medium.Each liquid at a certain temperature has the corresponding saturated vapor pressure.When the suction area of the absolute pressure the closer it gets to the saturated vapor pressure of liquid, the closer the boiling liquid state.At this moment, in the suction area of the surface of the working liquid will produce a lot of bubbles, the working liquid generated in the liquid in the working chamber steam will occupy part of the working space of the cavity, pump foreign inspiratory capacity will fall.When the pressure of the suction area to achieve the working liquid saturation vapour pressure, can think all working cavity filled with fluid steam, the pump’s suction capacity close to 0, while the pump cavitation phenomenon also is most serious.
If the working fluid is water, the higher the temperature, the pump suction performance declined more.Water temperature of water ring vacuum pump of the effects of extraction rate can consult other articles.
Water ring pump cavitation damage and the centrifugal pump cavitation damage on the same principle, is in the bubble production and the broken parts, metal surface pitting phenomenon, can appear serious damage of honeycomb.If the vacuum pump impeller in the cavitation area has a larger residual stress, still can cause stress, crack.
Due to the vacuum pump cavitation, the bubble burst in high continuous, and with strong water hammer, and produce noise and vibration.Can hear the sound of the like explosion beans teardrops.Cavitation caused by the testing results show that the vibration frequency range is 600 ~ 25000 hz, the pressure of 49 mpa.
If the bubble burst on the metal surface, continuous strong water hammer on the metal surface, pitting, loose grain and metal flake and honeycomb, even perforation.Cavitation damage in addition to the mechanical action, also from electrolysis, chemical corrosion and so on the many kinds of complex function.Actual damage shows that the pump flow components cavitation damage parts, is the place of bubbles disappear.
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