Vacuum-generating pumping system and pumping method using this pumping system

Abstract

The present invention relates to a pumping system to generate a vacuum (SP), comprising a main vacuum pump which is a dry screw pump (3) having a gas suction inlet (2) connected to a vacuum chamber (1) and a gas discharge outlet (4) leading into a gas evacuation conduit (5) in the direction of a gas exhaust outlet (8) outside the pumping system. The pumping system comprises a non-return valve (6) positioned between the gas discharge outlet (4) and the gas exhaust outlet (8), and an auxiliary vacuum pump (7) connected in parallel to the non-return valve. In a pumping method by means of this pumping system (SP), the main vacuum pump (3) is started up in order to pump the gases contained in the vacuum chamber (1) and to discharge these gases through its gas discharge outlet (4), simultaneously to which the auxiliary vacuum pump (7) is started up. Moreover the auxiliary vacuum pump (7) continues to pump all the while that the main vacuum pump (3) pumps the gases contained in the vacuum chamber (1) and / or all the while that the main vacuum pump (3) maintains a defined pressure in the vacuum chamber (1).

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to the field of vacuum technology. More precisely, it concerns a pumping system comprising a dry screw pump as well as a pumping method by means of this pumping system.PRIOR ART[0002]The general objectives to increase the performance of vacuum pumps, to reduce the costs of installations and the consumption of energy in industries such as the chemical industry, the pharmaceutical industry, the vacuum deposition industry, the semiconductor industry, etc., have led to significant developments in terms of performance, energy economy, bulkiness, in the drives, etc.[0003]The state of the art shows that to improve the final vacuum supplementary stages must be added in vacuum pumps of the multi-stage Roots or multi-stage claw type. For the dry vacuum pumps of screw type it is known that additional turns of the screw must be provided and / or the rate of internal compression increased.[0004]The speed of rotation of the pump pl...

AI Technical Summary

Benefits of technology

The present invention aims to reduce the energy required for vacuum evacuation and maintaining a vacuum, as well as lower the temperature of the exit gas. The invention provides a simple and cost-effective pumping system without the need for specific measures or apparatuses. The main vacuum pump can operate at a single constant speed or at variable speeds based on its own mode of operation, further reducing the complexity and cost of the pumping system. The auxiliary pump has high chemical resistance to substances commonly used in the semiconductor industry. The invention also includes a study to reduce the space between the gas discharge outlet and non-return valve to lower the pressure more quickly.

Problems solved by technology

Speed variation by variable speed drive entails additional costs and more bulkiness.

This solution requires numerous parts and presents problems of reliability.

This type of systems is bulky, operates either with by-pass valves presenting problems of reliability or by employing means of measurement, control, adjustment or servo-control.

However, these means of control, adjustment or servo-control must be controlled in an active way, which necessarily results in an increase in the number of components of the system, its complexity and its cost.

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