What is the working principle of the water ring vacuum pump?

The water ring vacuum pump (abbreviated as the water ring pump) is a crude vacuum pump. The ultimate pressure it can obtain is 2.66 to 9.31 kPa for single-stage pumps and 0.133 to 0.665 kPa for double-stage pumps. The water ring pump can also be used as a compressor, which belongs to a low-pressure compressor with a pressure range of (1 to 2) X105 Pa gauge pressure (under specific conditions). Water ring pumps are used in many processes such as petroleum, chemical, machinery, mining, light industry, papermaking, power, metallurgy, medicine, food, and other industrial and municipal and agricultural sectors such as vacuum filtration, vacuum feeding, vacuum degassing, vacuum Evaporation, vacuum concentration and vacuum rejuvenation have been widely used. Since the water ring pump compresses gas in a process that is isothermal, flammable and explosive gases can be extracted, and dust-laden, water-containing gases can be removed. Therefore, the application of water ring pumps is increasing.

The impeller is eccentrically installed in the pump body. When the impeller rotates in the direction as shown in the figure, the water entering the pump body of the water ring pump is thrown around by the impeller. Due to the centrifugal force, the water forms an equal thickness with the shape of the pump chamber. Closed water ring. The upper inner surface of the water ring is just tangent to the impeller hub (eg, I-I section), and the lower inner surface of the water ring is just in contact with the tip of the blade (actually, the blade has a certain depth of insertion 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 into several small cavities equal to the number of blades by the impeller. If the starting point of the upper part of the impeller is 0°, the volume of the small cavity gradually increases from small to large (that is, from section I-I to II-II) when the impeller is rotated 180°, and the pressure is continuously reduced, and the suction is reduced. The suction port on the air plate communicates. When the pressure in the small chamber space is lower than the pressure in the pumped container, according to the principle of gas pressure balance, the pumped gas is continuously pumped into the small chamber. process. When the suction is completed, it is isolated from the suction port. From the II-II to III-III sections, the volume of the small chamber is gradually reduced and the pressure is continuously increased. At this time, the compression process is in progress. When the compressed gas reaches the row in advance At the time of air pressure, exhaust from the auxiliary exhaust valve. From section III-III to I-I, the volume of the small chamber communicating with the exhaust port further reduces the further increase in pressure. When the gas pressure is greater than the exhaust pressure, the compressed gas is discharged from the exhaust port. Discharge, in the continuous operation of the pump, continuous suction, compression, exhaust process, so as to achieve the purpose of continuous pumping.

In the water ring pump, the auxiliary exhaust valve is a special structure, generally rubber ball valve, and its role is to eliminate the phenomenon of over-compression and compression in the pump during operation. Both of these phenomena cause excessive power consumption. Since the water ring pump does not have a direct exhaust valve and the discharge pressure is always fixed, the compression ratio of the water ring pump is determined by the end position of the air inlet and the starting position of the air outlet. However, these two positions are fixed. Unchanged, it does not adapt to the need for changes in suction pressure. In order to solve this problem, a rubber ball valve is generally provided below the exhaust port so that when the exhaust pressure is reached prematurely in the pump chamber, the ball valve is automatically opened and the gas is discharged, eliminating over-compression. Generally when designing the water ring pump, the compression ratio is determined with the lowest suction pressure, so as to determine the starting position of the exhaust port, so that the phenomenon of insufficient compression is solved.