Rotary vane vacuum pump (referred to as rotary vane pump) is a kind of oil-sealed mechanical vacuum pump, the working pressure range of 101325 ~ 1.33 × 10-2 (Pa) belong to the low vacuum pump. It can be used alone or as a foreline pump for other high-vacuum or ultra-high vacuum pumps. It has been widely used in metallurgy, machinery, military, electronics, chemicals, light industry, petroleum and other production and research departments. Rotary vane vacuum pump vacuum technology is one of the most basic vacuum access equipment. Rotary vane pump for small and medium-sized pump, rotary vane pump has a single-stage and two-stage two. The so-called two-stage, is the structure of two single-stage pump in series. Generally made more double-stage, in order to obtain a higher degree of vacuum. Rotary vane vacuum pump is mainly composed of a pump body, a rotor, a rotary plate, an end cover, a spring, etc. A rotor is eccentrically installed in the cavity of the rotary vane pump, and the outer circumference of the rotor is tangent to the inner surface of the pump cavity Small gap), the rotor slot is equipped with two rotating blades with spring, rotating, by centrifugal force and spring tension so that the top of the rotary vane and the inner wall of the pump chamber to maintain contact, the rotor rotates the rotary vane slide along the inner wall of the pump chamber. The two vanes separate the crescent-shaped space enclosed by the rotor, the pump chamber and the two end caps into three sections A, B and C. When the rotor rotates in the direction of the arrow, the volume of the space A communicating with the suction port is Gradually increasing, is in the process of inhalation, and the volume of the space communicating with the exhaust port C is gradually reduced, is in the process of exhausting, the volume of the center of the space B is also gradually reduced, is in the process of compression. Since the volume of space A is gradually increased (ie, expanded), the pressure of the gas is decreased and the pressure of the external gas at the inlet of the pump is greater than the pressure in space A. Therefore, gas is sucked in. When space A is isolated from the suction port, Space B, the gas began to be compressed, the volume gradually reduced, and finally connected with the exhaust port when the compressed gas exceeds the exhaust pressure, the exhaust valve is compressed gas pushed open, the gas through the reservoir within the oil layer to the atmosphere In the continuous operation by the pump to achieve the purpose of continuous extraction If the discharge of gas through the airway and transferred to another level (low vacuum level), from the low vacuum level pumping away, and then by the low vacuum level after the row to The atmosphere, which constitutes a two-stage pump, when the total compression ratio by two negative , Thus increasing the limit vacuum.