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Knowledge content of Roots vacuum pump

2024-02-24

Summary

The arrangement of the two rotors of the Roots vacuum pump in the pump body determines the overall structure of the pump. There are three general structural arrangements of Roots vacuum pumps at home and abroad: Vertical: The axes of the two rotors are installed horizontally, but the plane formed by the axes of the two rotors is perpendicular to the horizontal plane.

The arrangement of the two rotors of the Roots vacuum pump in the pump body determines the overall structure of the pump. Domestic and foreignRoots vacuum pumpThere are three general structural arrangements:

  

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1. Vertical: The axes of the two rotors are installed horizontally, but the plane formed by the axes of the two rotors is perpendicular to the horizontal plane. In this structure, the inlet and outlet of the pump are arranged horizontally, which is convenient for assembly and connection of pipelines. But its disadvantage is that the center of gravity of the pump is too high, and the stability is poor when running at high speed. Therefore, in addition to small pumps, there are not many pumps with this structure.

2. Horizontal: The two rotor axes are installed horizontally, and the plane formed by the two rotor axes is horizontal. The intake port of the pump of this structure is above the pump, and the exhaust port is below the pump (there is also the opposite). The lower exhaust ports are usually connected horizontally, so the intake and exhaust directions are perpendicular to each other. The exhaust port is connected to a tee, and the tee opens in both directions. One end is connected to the exhaust pipe, and the other end is not energized or connected to the bypass valve. This structure is characterized by a low center of gravity and good stability during high-speed operation. Most large and medium-sized pumps at home and abroad use this type of structure.

3. Vertical shaft type: the two rotor shafts of some foreign Roots vacuum pumps are installed vertically with the horizontal plane. The assembly gap of this structure is easy to control, the rotor is convenient to assemble, and the floor area is small, but the disassembly and assembly of the transmission mechanism such as gears are inconvenient, and the lubrication device is complicated.

After determining the overall structure, the structure and shape of the pump body itself are also determined.

Roots vacuum pump with overflow valve: In order to prevent accidents caused by overload,Roots vacuum pumpEquipped with a more reliable safety protection device, that is, an overflow valve is installed on the bypass pipeline. When the exhaust port is at the specified pressure, the overflow valve is closed. When the pressure at the exhaust port exceeds the specified pressure, the valve of the overflow valve will automatically open to generate overflow. After the exhaust port pressure is normal, the overflow valve will automatically close. It can be automatically adjusted and is the allowable pressure difference device of the pump. Therefore, the great advantage of the overflow valve is that the Roots vacuum pump can operate continuously in various pressure ranges together with the pre-pump. Through this design, the pump stop time of the vacuum vessel in the rough vacuum state can be shortened by 30 ~ 50%. For larger pumps, the overflow valve is installed on the bypass pipe outside the pump body, while for smaller pumps, the overflow valve is installed in the pump housing.

with steam condenserRoots vacuum pump: When it is necessary to pump steam, the air extraction device needs to design a condenser to condense the steam. The condenser can be installed before or after the pump, rather than on the pump body of the Roots pump. In some cases, the heat absorption of the condensate upgrade can reduce the heating of the Roots pump. Assuming that a compound condenser is used, appropriate solvents can be used to remove dirt during maintenance, and steam can flow smoothly in the pipeline.