How to select a water ring vacuum pump

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How to select a water ring vacuum pump I. Determination of the pump type The type of pump is mainly determined by the volume of air required for operation, the level of vacuum, or the exhaust pressure. When the pump is in operation, attention should be paid to the following two aspects: 1. It is necessary to operate it as much as possible within the high-efficiency range, that is, within the range of critical vacuum level or critical exhaust pressure. 2. Operation near high vacuum levels or high exhaust pressures should be avoided. Operating in this area not only results in extremely low efficiency, but also leads to unstable operation, with frequent vibrations and noise. For vacuum pumps with a high degree of vacuum that operate in this range, cavitation often occurs as well; obvious signs of this phenomenon are noise and vibration inside the pump. Cavitation can cause damage to components such as the pump body and impeller, resulting in the pump being unable to function. Based on the above principles, when the vacuum level or gas pressure required by the pump is not high, a single-stage pump should be preferred. If the vacuum level or exhaust pressure is high, a single-stage pump often fails to meet the requirements. Alternatively, if it is necessary for the pump to handle a large volume of gas at high vacuum levels, that is, if a relatively flat performance curve at high vacuum levels is required, a two-stage pump can be used. If a vacuum level of above –710 mmHg is required, a water ring-atmospheric pump or a water ring-Rotary vane vacuum unit can be used as the vacuum pumping device. If it is to be used only as a vacuum pump, a single-acting pump is a better choice. This is because single-acting pumps have a simple structure, are easy to manufacture and maintain, and exhibit good cavitation resistance in high-vacuum conditions. If it is to be used only as a compressor with a large capacity, a double-acting pump is more suitable. Because double-acting pumps have a large air volume, small size, and light weight, the radial forces can be automatically balanced, the shaft is less prone to fatigue fracture, and thus the pump has a longer service life. II. Selecting the vacuum pump based on the air volume required by the system: After initially determining the type of pump, it is also necessary to choose the specific model of the vacuum pump according to the amount of air required by the system. For the selection of the pumping speed and the calculation of the pumping time for vacuum pumps, refer to: Vacuum calculation formulas.