Composite dry vacuum pump with Roots rotors and screw rotors connected in series and use method of composite dry vacuum pump

Abstract

The invention relates to a composite dry vacuum pump with Roots rotors and screw rotors connected in series and a using method, the composite dry vacuum pump comprises a driving rotor combination, a driven rotor combination and a pump body combination, the driving rotor combination comprises a driving rotor shaft and a driving Roots rotor body, a driving screw rotor body is machined in the middle of the driving rotor shaft, and the driving Roots rotor body is arranged on a driving front end shaft in a sleeving mode; the driven rotor assembly comprises a driven rotor shaft and a driven roots rotor body; a driven screw rotor body is processed in the middle of the driven rotor shaft; the driven roots rotor body is sleeved on a driven front end shaft; the pump body combination comprises a front end plate, a roots pump body, a middle partition plate, a screw pump body, a rear pump body and a rear end plate which are sequentially connected in a sealed mode. The Roots stage is provided with a Roots stage overflow valve and an overflow channel, the middle partition plate is provided with a backflow valve and a backflow channel, and the screw stage is provided with an air inlet valve plate, a discharge valve, a discharge channel and a slag storage chamber with a slag removal opening. The vacuum unit can replace a conventional Roots-screw vacuum unit in practical application, and has the characteristics of high efficiency, energy conservation, dust pollution resistance, simple structure, low cost and convenience in operation.

Description

technical field [0001] The invention belongs to the technical field of vacuum pumps, and in particular relates to a composite dry vacuum pump in which a Roots rotor and a screw rotor are connected in series and a use method thereof. Background technique [0002] The Roots-screw dry vacuum pump unit composed of an oil-free screw vacuum pump and a Roots pump has a higher ultimate vacuum and a wider working pressure range than a single screw pump, and is widely used in semiconductors, medicine, Food, chemical and many other industrial fields. Conventional Roots-screw vacuum units are composed of two independent Roots pumps and screw pumps in series. The Roots pumps and screw pumps are driven by their own motors, and often need to be powered by two independent frequency converters. and control. This conventional Roots-screw vacuum unit composition method, for some situations that require a small pumping capacity but the ultimate pressure is in the range of medium vacuum, espec...

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Problems solved by technology

The second is that the Roots-screw pumping speed ratio should not be too large, the motor power configuration is too large, and the pumping speed is reduced under high inlet pressure and the power consumption is increased. As the gas pressure rises, the inlet pressure of the screw rotor is always in an overload state higher than the atmospheric pressure even if the flow is diverted through the intermediate pressure relief valve, which causes the Roots stage and the screw stage to be in a high-load working state at the same time, so the whole machine must be Equipped with a high-power motor, the actual pumping speed is greatly reduced under high pressure with frequency conversion and reduced speed, and the power consumption is greatly increased, and the pumping efficiency is reduced.

It is for these reasons that the composite dry vacuum pump, which consists of Roots rotors and screw rotors in series, has not been actually produced and used so far.

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