Water ring vacuum pump (abbreviated as water ring pump) is a kind of rough vacuum pump. The ultimate pressure it can obtain is 2.66～9.31kPa for single-stage pump and 0.133～0.665kPa for two-stage pump. The water ring pump can also be used as a compressor. It is a low-pressure compressor with a pressure range of (1～2)X105Pa gauge pressure (under specific conditions). Water ring pumps are used in many processes in petroleum, chemical, machinery, mining, light industry, paper, power, metallurgy, medicine and food industries, municipal and agricultural sectors, such as vacuum filtration, vacuum feeding, vacuum degassing, and vacuum Evaporation, vacuum concentration and vacuum regaining, etc., have been widely used. Because the process of compressing gas by the water ring pump is isothermal, it can extract flammable and explosive gases. In addition, it can also extract dust and water-containing gases. Therefore, the application of water ring pumps is increasing day by day.

The impeller is eccentrically installed in the pump body. When the impeller rotates in the direction shown in the figure, the water entering the water ring pump body is thrown around by the impeller. Due to the centrifugal force, the water forms an equal thickness similar to the shape of the pump cavity. Closed water ring. The upper inner surface of the water ring is just tangent to the impeller hub (such as the Ⅰ-I section), and the lower inner surface of the water ring just touches the top of the blade (in fact, the blade has a certain insertion depth in the water ring). At this time, a crescent-shaped space is formed between the impeller hub and the water ring, and this space is divided by the impeller into several small cavities equal to the number of blades. If the upper part of the impeller is 0° as the starting point, when the impeller rotates 180° before the rotation, the volume of the small cavity gradually changes from small to large (that is, from section Ⅰ-Ⅰ to Ⅱ-Ⅱ), the pressure is continuously reduced, and the suction and discharge The suction ports on the gas plate are connected. When the pressure in the small cavity space is lower than the pressure in the container to be pumped, according to the principle of gas pressure balance, the pumped gas is continuously drawn into the small cavity, and it is in suction at this time. process. When the suction is completed, it is isolated from the suction port. From the section Ⅱ-Ⅱ to Ⅲ-Ⅲ, the volume of the small cavity is gradually decreasing, and the pressure is increasing. At this time, it is in the compression process. When the compressed gas reaches the discharge ahead of time. At the time of air pressure, exhaust air from the auxiliary exhaust valve in advance. From section Ⅲ-Ⅲ to Ⅰ-Ⅰ, the volume of the small cavity connected to the exhaust port is further reduced and the pressure is further increased. When the pressure of the gas is stronger than the exhaust pressure, the compressed gas is removed from the exhaust port. Discharge, during the continuous operation of the pump, the process of suction, compression, and exhaust is continuously carried out, so as to achieve the purpose of continuous pumping.

In the water ring pump, the auxiliary exhaust valve is a special structure. Generally, a rubber ball valve is used. Its function is to eliminate the phenomenon of over-compression and under-compression during the operation of the pump. Both of these phenomena will cause excessive power consumption. Because the water ring pump does not have a direct exhaust valve, and the exhaust pressure is always fixed, the compression ratio of the water ring pump is determined by the end position of the air inlet and the start position of the air outlet, but these two positions are fixed Unchanging, so it does not meet the needs of changes in suction pressure. In order to solve this problem, a rubber ball valve is generally installed under the exhaust port, so that when the exhaust pressure in the pump cavity is reached prematurely, the ball valve opens automatically and the gas is discharged, eliminating the over-compression phenomenon. Generally, the lowest suction pressure is used to determine the compression ratio when designing the water ring pump, and the starting position of the exhaust port is determined by this, which solves the phenomenon of insufficient compression.