When the liquid ring vacuum pump is working, at a certain temperature, when the pressure of the liquid at the low pressure is lower than the vaporization pressure at that temperature, the liquid starts to vaporize and form bubbles. And with the liquid into the high-pressure area, the bubble rupture, the surrounding liquid quickly fill the original bubble cavity, resulting in hydrodynamic impact. This bubble generation, growth and rupture phenomenon known as cavitation. In order to help water ring vacuum pumps avoid cavitation, we show some methods that can avoid vacuum pump cavitation.
Water ring vacuum pumps are usually used in many industrial sectors such as petroleum, chemical, machinery, mining, light industry, medicine and food. In many processes of industrial production, such as vacuum filtration, vacuum priming, vacuum feeding, vacuum evaporation, vacuum concentration, vacuum rewetting and vacuum degassing, water ring vacuum pumps are widely used. At the same time, it can also pump out flammable, explosive, dust-containing and water-containing gases.
1. Installation of cavitation valve
For this phenomenon, impellers are available in copper impeller, stainless steel impeller, and stainless steel materials. The industrial vacuum pump has a cavitation valve up front. If the cavitation sound is very loud, open the valve slightly to lessen the noise. However, because the vacuum would be significantly lowered, it is not appropriate for procedures that need for high vacuum.
2. Increase the water's temperature
The heat of the vacuum pump sealing water must be lower than the saturation heat corresponding to the exhaust pressure, otherwise, the vacuum pump impeller may cavitate and fail. This is because the temperature of the icing water in the vacuum pump will cause its pumping energy to rise significantly. Consequently, in order to accomplish the goal of avoiding cavitation, the water's temperature might be increased.
3. Use of atmospheric jets
Atmospheric ejectors use the pressure difference between the vacuum pump and the atmosphere to generate atmospheric jets and lose suction pressure in the ejector that is lower than that of the vacuum pump, thus serving to cover the vacuum pump, preventing corrosion in the vacuum pump and eliminating the limit pressure of the water vacuum pump.
4. Anti-cavitation treatment using strong materials
The cavitation resistance of various materials varies greatly, and many components affect a material's resistance to cavitation. In general, materials with high elasticity and hardness are more resistant to cavitation. The steps involved in impeller coating are not common, and non-metallic coatings such as epoxy, nylon powder, and polyurethane can be used. Stainless steel wire welding and alloy powder spray welding are two examples of runner welded alloys or coated alloys to reduce cavitation damage for the same purpose.
5. The cavitation cover tube installation
When a vacuum pump with a cavitation cover tube is compressed, the bubble created within the cavitation bursts. This allows non-condensable gas introduced from the inside at a higher pressure to promptly fill the space left by the burst bubble, greatly exacerbating the damage caused by cavitation to the pump and increasing the noise and vibration caused by cavitation.
To sum up the water ring vacuum pump cavitation has a great impact on the vacuum pump, cavitation conditions for a long time work, will constitute the pump noise, vibration becomes larger, and even the pump constitutes damage, and even produce unnecessary losses, increase the vacuum pump maintenance costs. So we provide some methods to eliminate water ring vacuum pump cavitation, to help you reduce machine damage and production losses.
