piston vacuum pump is mainly composed of stator, rotor, rotary vane, fixed cover, spring and other parts. The structure uses the rotor which is eccentrically mounted in the stator cavity (the gap between the outer circle of the rotor and the inner surface of the stator is very small) and the two rotating blades which are close to the inner wall of the stator by means of spring tension and centrifugal force, sliding along the inner wall of the stator when the rotor rotates.
When the rotor rotates in the graphic direction, the volume of space A connected with the suction port increases continuously, and the pressure in space A decreases continuously. When the pressure in space A is lower than the pressure in the suction container, according to the gas The principle of pressure equilibrium is that the gas pumped is continuously pumped into the suction chamber A, which is in the process of inspiration. The volume of B cavity is decreasing and the pressure is increasing. When the pressure of the gas is stronger than the exhaust pressure, the compressed gas pushes the exhaust valve away, and the exhausted gas continuously passes through the oil layer in the tank and is discharged into the atmosphere. During the continuous operation of the pump, it continuously sucks. Gas, compression and exhaust process, so as to achieve continuous pumping purposes. In water ring pump, auxiliary exhaust valve is a special structure, generally using rubber ball valve, its role is to eliminate the pump in the operation process of the phenomenon of excessive compression and insufficient compression. These two phenomena can cause excessive power consumption.
Because the water ring pump has no direct exhaust valve, and the exhaust pressure is always fixed, the compression ratio of the water ring pump depends on the end position of the intake port and the start position of the exhaust port, but these two positions are fixed and unchanged, so they are not suitable for the needs of suction pressure changes. In order to solve this problem, a rubber ball valve is usually installed below the exhaust port, so that when the pump cavity reaches the exhaust pressure prematurely, the ball valve opens automatically and the gas is discharged, eliminating the phenomenon of over-compression.
In general, the minimum suction pressure is used to determine the compression ratio in the design of water ring pump, so as to determine the starting position of the exhaust port, thus solving the problem of insufficient compression. The pumping principle of slide valve vacuum pump is similar to that of chip pump. The piston vacuum pump uses the slide valve mechanism to change the volume of the west air chamber, so it is called Huafa pump. piston vacuum pump is an old pump, but compared with rotary vane pump, it has the outstanding characteristics of allowing high working pressure (104pa), large pumping capacity, continuous operation in harsh environment, durable and so on, so it is widely used in vacuum smelting, vacuum drying, vacuum impregnation, vacuum distillation and other industries. At present, the oil-sealed vacuum pump widely used in the vacuum industry is mostly medium and small-sized chip selection pump and medium and large-scale Huafa pump. Rotary vane pumps are stuck in rotor grooves under dirty working conditions.