Vacuum pumps are generally used for vacuum pumping, but not all occasions require the lower the vacuum, the better. In some cases, it is required to control in a certain vacuum range, or the pressure of the vacuum chamber is too low. Serious cavitation will occur in the pump chamber, resulting in pump vibration and noise, which will affect the use of the pump. F time can be added in the suction zone of the pump. When the above situation occurs, the vacuum regulating valve can be properly opened to alleviate the impact of vibration and noise, or to reduce the vacuum degree to meet the required vacuum requirements. This is a more reasonable way to apply vacuum pump.
2. The Role of Atmospheric Ejector
Any liquid has vaporization pressure at any temperature. The limit vacuum of water ring vacuum pump is related to the saturated vapor pressure of the liquid circulation in the vacuum pump. The lower the limit vacuum degree of vacuum pump is, the higher the limit vacuum degree is. From Figure 1, it can be seen that the vacuum state is formed in the cavity during the pumping process of vacuum pump 1-5. According to Dalton's law, liquid rings are stirred by impellers. We believe that when the inhaled gas is zero, the sum of saturated vapor pressure and inhaled gas pressure filled with liquid circulation in the 1-5 cavity is the lowest and the vacuum degree is the highest. At this time, the suction pressure of the vacuum pump is the lowest, and the vacuum degree of the cavity 1-5 is the highest. The pressure is the saturated vapor pressure of the liquid ring. Therefore, the minimum absolute pressure at the inlet of the vacuum pump must be the saturated vapor pressure as the liquid ring medium at that temperature.
3. Effect of Auxiliary Working Fluid System on the Performance of Vacuum Pump
The working fluid must be continuously replenished. However, in order to improve the performance of vacuum pumps, it is necessary to determine the way of replenishing working fluid and how to determine the flow rate and pressure of replenishing working fluid.
4. Reducing working fluid temperature and increasing vacuum degree of pumping unit
It is known that the vaporization pressure of the liquid has a great relationship with the temperature of the liquid. High temperature and vaporization pressure will lead to low vacuum of the pump. Therefore, lowering the temperature of the working fluid will help to improve the vacuum of the pump. For the high temperature workflow, it is necessary to reduce the temperature of the workflow by heat transfer to improve the vacuum degree of the vacuum pump. As shown in Figure 4. Taking water as an example, the saturated vapor pressure of water is 0.0233 bar at 20 o'clock and 0.1234 bar at 50 o'clock. The saturated vapor pressure of water has increased more than five times.
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