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What is the working principle of Roots vacuum pump

2024-02-08

Summary

Roots vacuum pump (hereinafter referred to as Roots pump) is a variable volume vacuum pump, two vane rotor synchronous reverse rotation. There is a small gap between the rotors and between the rotors and the inner wall of the pump housing. Roots vacuum pump has been in aerospace simulation, plastics, petroleum, chemical, steam turbine rotor dynamic balance and other equipment for long-term operation test, should be vigorously promoted in China.

  Roots vacuum pump(Hereinafter referred to as Roots pump) is a variable volume vacuum pump with two vane rotors rotating synchronously in reverse. There is a small gap between the rotors and between the rotors and the inner wall of the pump housing.

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Roots vacuum pump has been in aerospace simulation, plastics, petroleum, chemical, steam turbine rotor dynamic balance and other equipment for long-term operation test, should be vigorously promoted in China. At the same time, it is also widely used in metallurgy, textile and other industries. The vacuum pump accessory is used as a vacuum pump muffler for noise control of the vacuum pump.

Roots vacuum pump is a vacuum pump without internal compression. Generally speaking, the compression ratio is very low, so high and medium vacuum pumps require a pre-pump.

It is a vacuum pump that achieves pumping by moving gas under the pushing action of synchronous and reverse rotation of a pair of vane rotors in the pump cavity.

  Roots vacuum pumpIt is a mechanical vacuum pump with a pair of high-speed synchronous rotating sole rotors. This pump cannot pump air alone. The front stage needs to be equipped with oil seals, water rings, etc. to directly discharge the atmosphere.

Its structure and working principle are similar to Roots blower. In operation, the suction port is connected to the vacuum container or the main pump of the vacuum system. Vacuum pump rotor and rotor, rotor and pump shell without contact,

The gap is generally 0.1~0.8mm; oil lubrication is not required. The rotor profile includes circular arc, involute and cycloid. The involute rotor pump has the advantages of high volume utilization rate and easy to ensure the machining accuracy, so the involute rotor type line is mainly used. The rotation speed of Roots vacuum pump can be as high as 3450~4100rpm; The extraction rate is 30 ~ 10000L/S(1L = 10~3m3); Ultimate vacuum: single stage is 6.5 × 102Pa, and double stage is 1 × 103Pa.

The maximum vacuum degree of Roots vacuum pump depends not only on the structure and manufacturing accuracy of the pump itself, but also on the maximum vacuum degree of the pre-pump. In order to improve the vacuum degree of the pump, Roots vacuum pump can be used in series.Roots vacuum pumpThe working principle is similar to Roots blower. As the rotor continues to rotate, the extracted gas is sucked into the space V0 between the rotor and the pump housing from the intake port. It is then exhausted through the exhaust port. Since the V0 space is completely closed after suction, the gas in the pump chamber is not compressed and expanded. However, when the top of the rotor rotates around the edge of the exhaust port and the V0 space is connected to the exhaust side, some gas will recoil into the space V0 due to the high gas pressure on the exhaust side, resulting in a sudden increase in gas pressure. As the rotor continues to rotate, gas is expelled from the pump. In the pump chamber of the Roots pump, two "8"-shaped rotors are installed on a pair of parallel shafts perpendicular to each other, and a pair of gear belts with a transmission ratio of 1 act in reverse to rotate synchronously with each other. There is a certain gap between the rotor and the inner wall of the pump casing, which can realize high-speed operation.

The above isRoots vacuum pumpThe working principle of the relevant content is introduced.