Composite screw vacuum pump with built-in exhaust superchargers

Abstract

The invention belongs to the field of screw vacuum pumps, and relates to a composite screw vacuum pump with built-in exhaust superchargers. The composite screw vacuum pump solves the problems that an existing screw vacuum pump is high in energy consumption, low in pumping efficiency at a low vacuum stage and not suitable for large-scale rapid manufacturing. According to the composite screw vacuum pump, a pair of Roots rotor exhaust superchargers are arranged at exhaust ends of a pair of screw rotors meshed with each other, the Roots rotor exhaust superchargers are installed in a pump body which is divided by a middle partition plate to form two pump cavities, and each pump cavity is provided with a middle air guide channel, a middle exhaust channel and a check valve (one-way valve); a large compression ratio is formed by the Roots rotor exhaust superchargers and the screw rotors, and at the low vacuum stage, air sucked in by the screw rotors can eject the check valves to be exhausted from exhaust ports through the middle exhaust channels; and at a high vacuum stage, low-pressure air sucked in by the screw rotors is exhausted from the exhaust ports after being compressed by the exhaust superchargers. The composite screw vacuum pump has the advantages of being low in energy consumption, high in pumping efficiency, convenient to manufacture and compact in structure.

Description

technical field [0001] The invention belongs to the field of screw vacuum pumps, and relates to a compound screw vacuum pump with a built-in exhaust supercharger (hereinafter referred to as a compound screw vacuum pump). Background technique [0002] Screw vacuum pump is a relatively new product in the field of vacuum pumps. At present, the screw vacuum pumps on the market mainly include: equal-pitch screw vacuum pumps, variable-pitch screw vacuum pumps, and multi-stage equal-pitch screw vacuum pumps. [0003] For equal-pitch screw vacuum pumps, the structure is relatively simple, and the rotor can be manufactured in a variety of ways, such as lathes, turning and milling centers, and for mass production, forming milling cutters and forming grinding wheels can also be used for rapid manufacturing. But it also has its disadvantages, that is, relatively high energy consumption. For the variable-pitch vacuum pump, although it has a simple structure and relatively low power cons...

AI Technical Summary

Problems solved by technology

But it also has its disadvantages, that is, relatively high energy consumption

For the variable-pitch vacuum pump, although it has a simple structure and relatively low power consumption, there are also problems that the rotor can only be processed by a lathe or a turning-milling compound center with a slow processing speed, and cannot be manufactured with a forming milling cutter and a forming grinding wheel. Low, not suitable for mass production; in the case of high inlet pressure, the load is too large due to internal compression, or the pumping efficiency is reduced due to excessive backflow, so that it cannot be achieved at a higher pressure strong pumping speed

At the same time, considering the thermal stability of the rotor structure size, the rotor pitch cannot be made too small, so there is also the problem that the compression ratio is small, and it is difficult to increase the compression ratio to more than 5:1, and there are certain limitations in energy saving.

Although the multi-stage equal-pitch screw vacuum pump can theoretically increase the compression ratio to a large value, and the rotor can also be mass-produced using forming milling cutters and forming grinding wheels, the actual implementation process has complex rotor structures and is difficult to achieve miniaturization, etc. question

Multi-stage equal-pitch screw vacuum pumps also have the problem of reduced pumping efficiency under high inlet pressure of variable-pitch screw vacuum pumps. To solve this problem, it is necessary to set up complex exhaust bypass pipelines, which will make the casting of the pump body very complicated. , easily lead to low yield

[0004] In addition, no matter it is the existing equal-pitch vacuum pump, variable-pitch vacuum pump or multi-stage equal-pitch vacuum pump, the most calorific value is always the exhaust rotor in the last circle. The three-dimensional irregularity of the rotor shape of the screw vacuum pump makes the deformation of the rotor change after heating It is very complicated. In the process of research and development, a large number of experiments are required to obtain multiple sets of data to optimize the size between the rotor and the rotor, and between the rotor and the pump body.

Unoptimized dimensions can easily cause problems such as unstable pump operation, poor vacuum, and low efficiency

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