How does a vacuum pump work?

An appropriate amount of water is placed in the pump body as the working fluid. As the impeller rotates clockwise, water is thrown out in all directions by the impeller; due to centrifugal force, the water forms a closed ring of approximately uniform thickness, whose shape is determined by that of the pump chamber. The inner surface of the upper part of the water ring is in perfect tangent with the impeller hub, while the inner surface of the lower part of the water ring is in contact with the tips of the blades (in fact, the blades extend to a certain depth within the water ring). At this point, a crescent-shaped space is formed between the impeller hub and the water ring, and this space is further divided by the impeller into several small chambers, each containing an equal number of blades. If 0° at the upper part of the impeller is taken as the starting point, then 180° before the impeller starts rotating, the volume of the small chamber increases and it becomes connected to the suction port on the end face; at this point, gas is drawn in. Once suction is complete, the small chamber becomes separated from the suction port ； As the impeller continues to rotate, the small cavity becomes smaller, causing the gas to be compressed ； When the small chamber is connected to the exhaust port, the gas is expelled outside the pump. A water ring pump relies on changes in the volume of its pumping chamber to achieve suction, compression, and exhaust; therefore, it belongs to the category of variable-volume vacuum pumps

(1) An increase in the clearance between the impeller and the distributor, as well as between the impeller and the front and rear covers, affects the performance of the vacuum pump. It causes the entire P-S curve to shift downward. (2) Poor water quality leads to the formation of scale that adheres to the surfaces of the impeller blades and distributors, affecting the performance of the vacuum pump, resulting in a reduced suction volume and increased power consumption. (3) The amount of water added has a significant impact on vacuum level, exhaust volume, and shaft power. In principle, the amount of water to be supplied should correspond to the amount of water that has to be discharged along with the exhaust gas. (4) The sealing performance of the vacuum pump deteriorates. (5) Air leakage at the filler. (6) The temperature of the water ring inside the pump is high.