The steps and prevention of the cavitation phenomenon of water ring vacuum pump

Cavitation is caused by the vaporization of liquids. Liquid molecules escape the liquid name and become inside of gas molecules, which is called "gasification". The vaporization level of the liquid has nothing to do with the pressure and heat. The gas dissolved in the liquid will also be released when the pressure and heat change, forming air pockets. When the external pressure of the liquid province rises and is lower than the saturated vapor pressure of the liquid under this heat, bubbles or air pockets are formed in all the sea areas; while the bubbles in the center where the pressure rises are suddenly crushed by the pressure of the four places, and the liquid flow becomes elastic due to elasticity. The extremely high progress squeezed towards the core of the bubble, causing a hydraulic charge to the action. The generation, collapse and physical and chemical effects of such microbubbles are called cavitation. When the bubbles generated during cavitation are fixed to a low pressure, their volume decreases and bursts. This phenomenon of bubbles falling into the liquid due to the pressure rise is called cavitation collapse.

When the vacuum pump is in operation, if it flows over all the seas and territories (usually somewhere behind the entrance of the impeller blades). Therefore, the relative pressure of the pumped liquid rises to the vaporization pressure of the liquid under the subsequent heat. Vaporization ends at this point, and a large amount of steam is generated to form bubbles. When the liquid containing a large amount of bubbles passes through the low-pressure area in the impeller, the low-pressure liquid around the bubbles causes the bubbles to abruptly enlarge and burst. At the same time as the bubbles condense and burst, the liquid particles fill the cavities at a very high rate. At this moment, they produce a very strong water hammer, and hit the non-metal with a high charge and trap efficiency. The stress of the charge trap reaches as many as hundreds and thousands. At an atmospheric pressure, the efficiency of assault and trapping can reach tens of thousands of times per second, and the wall thickness will be penetrated in severe cases.

In the vacuum pump, the bubble produced and the bubble burst causes the flow element to be destroyed, which is the cavitation in the vacuum pump. After the vacuum pump produces cavitation, unless it destroys the flow components, it will also produce noise and vibration and cause the function of the pump to rise. When it is severe, the liquid in the pump will stop, so that the work cannot be deformed.

The cavitation damage of the water ring pump is where the bubbles are generated and ruptured. The appearance of pitting corrosion occurs in the name of non-metal, and the honeycomb damage occurs in major cases. However, the impeller of the empty pump has a large residual stress in the cavitation part, which will also cause stress release and cracks. Due to the sudden burst of bubbles in the low pressure area during pump cavitation, as well as the noise and vibration caused by strong water hammer, the tones of crackling like beans can be heard. Then the above-mentioned bubbles burst in the non-metallic name, and the non-metallic name will be hit by strong water successively, and the non-metallic crystal grains will loosen and peel off into a honeycomb or even perforation. In addition to mechanical effects, cavitation damage is accompanied by many simple effects such as electrolysis and chemical corrosion. The theoretical destruction idea shows that the part where the cavitation damage of the pump flow element is the center of the bubble loss. The vacuum pump needs to use liquid as the homework medium. Each liquid

There is a corresponding saturated vapor pressure at a certain degree of heat. When the relative pressure sucked into the sea is closer to the saturated vapor pressure of the liquid, the liquid is closer to evaporation. At that time, a large number of bubbles will be generated when inhaling the homework liquid in Haijiang. Because the homework liquid vapor generated by the liquid in the homework cavity will occupy the space of the whole homework cavity, the suction power of the pump will increase. When the suction pressure reaches the saturated vapor pressure of the successful class liquid, you can feel that the homework cavity is full of homework liquid vapor. At this time, the suction power of the pump is close to zero, and the cavitation of the pump is also the most significant.

Then the homework fluid is water, and the higher the water temperature, the more the pump's suction function will rise. The water temperature of the water ring vacuum pump is not necessary for its performance, and the performance curve of the water ring vacuum pump is measured under the premise of a water temperature of 15 ℃, so when the water ring vacuum pump is selected in theory, the pumping rate of the water ring vacuum pump is modified.