# US 2017/0284394 A1 · Pumping system for generating a vacuum and method for pumping by means of this pumping system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0284394 A1 - Document ID: US20170284394A1 - Status: Published application - Kind: A1 - Application number: 15/513,574 - Filed: 2014-10-02 - Published: 2017-10-05 - Earliest claimed: 2014-10-02 - Assignees: Ateliers Busch SA - Applicants: Ateliers Busch SA - Inventors: Didier MÜLLER; Jean-Eric LARCHER; Théodore ILTCHEV - Web page: https://patentgrep.com/patent/US20170284394A1 ## CPC - F04C 25/02: for producing high vacuum (sealing arrangements F04C27/00; silencing F04C29/06) - F04B 37/14: to obtain high vacuum - F04B 41/06: Combinations of two or more pumps - F04B 45/00: Pumps or pumping installations having flexible working members and specially adapted for elastic fluids - F04C 18/123: {with radially or approximately radially from the rotor body extending tooth-like elements, co-operating with recesses in the other rotor, e.g. one tooth} - F04C 23/005: {of dissimilar working principle} - F04C 28/02: specially adapted for several pumps connected in series or in parallel - F04D 19/046: {Combinations of two or more different types of pumps} - F04F 5/20: for evacuating - F04B 45/04: having plate-like flexible members, e.g. diaphragms (F04B45/10 takes precedence) - F04C 28/06: specially adapted for stopping, starting, idling or no-load operation - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F04F: PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED {(evacuating by sorption F04B)}; SIPHONS {(conveying materials in bulk by flows of gas, liquid of foam B65G53/00)} ## Abstract The present invention relates to a pumping system to generate a vacuum (SP), comprising a main vacuum pump which is a claw 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). ## Claims ### Claim 1 Pumping system for generating a vacuum, comprising a main vacuum pump which is a claw pump having a gas suction inlet connected to a vacuum chamber and a gas discharge outlet leading into a gas evacuation conduit in the direction of a gas exhaust outlet outside the pumping system, the pumping system being characterized in that it comprises a non-return valve positioned between the gas discharge outlet and the gas exhaust outlet, and an auxiliary vacuum pump connected in parallel to the non-return valve. ### Claim 2 (depends on 1) Pumping system according to claim 1, characterized in that the auxiliary vacuum pump is selected from among a dry screw pump, a claw pump, a multi-stage Roots pump, a diaphragm pump, a dry rotary vane pump and a lubricated rotary vane pump and a gas ejector. ### Claim 3 (depends on 2) Pumping system according to claim 2, characterized in that the auxiliary vacuum pump is a dry screw pump. ### Claim 4 (depends on 2) Pumping system according to claim 2, characterized in that the auxiliary vacuum pump is a claw pump. ### Claim 5 (depends on 2) Pumping system according to claim 2, characterized in that the auxiliary vacuum pump is a multi-stage Roots pump. ### Claim 6 (depends on 2) Pumping system according to claim 2, characterized in that the auxiliary vacuum pump is a diaphragm pump. ### Claim 7 (depends on 2) Pumping system according to claim 2, characterized in that the auxiliary vacuum pump a dry rotary vane pump. ### Claim 8 (depends on 2) Pumping system according to claim 2, characterized in that the auxiliary vacuum pump is a lubricated rotary vane pump. ### Claim 9 (depends on 1) Pumping system according to claim 1, characterized in that the auxiliary vacuum pump is an ejector. ### Claim 10 (depends on 9) Pumping system according to claim 9, characterized in that the working fluid of the ejector is compressed air or nitrogen. ### Claim 11 (depends on 9) Pumping system according to claim 9, characterized in that the flow of gas at the pressure necessary for the operation of the ejector is provided by a compressor. ### Claim 12 (depends on 11) Pumping system according to claim 11, characterized in that the compressor is driven by the main pump. ### Claim 13 (depends on 11) Pumping system according to claim 11, characterized in that the compressor is driven autonomously, independently of the main pump. ### Claim 14 (depends on 1) Pumping system according to claim 1, characterized in that the auxiliary vacuum pump is designed to be able to pump all the while that the main vacuum pump pumps the gases contained in the vacuum chamber and/or all the while that the main vacuum pump maintains a defined pressure in the vacuum chamber. ### Claim 15 (depends on 1) Pumping system according to claim 1, characterized in that the auxiliary vacuum pump comprises a discharge end which is connected downstream from the non-return valve, to the gas evacuation conduit. ### Claim 16 (depends on 1) Pumping system according to claim 1, characterized in that nominal flow rate of the auxiliary vacuum pump is selected as a function of the volume which the gas evacuation conduit delimits between the main vacuum pump and the non-return valve. ### Claim 17 (depends on 1) Pumping system according to claim 1, characterized in that the nominal flow rate of the auxiliary vacuum pump is from 1/500 to 1/5 of the nominal flow rate of the main vacuum pump. ### Claim 18 (depends on 1) Pumping system according to claim 1, characterized in that the auxiliary vacuum pump is single-staged or multi-staged. ### Claim 19 (depends on 1) Pumping system according to claim 1, characterized in that the non-return valve is configured to close when the pressure at the suction end of the main vacuum pump is less than 500 mbar absolute. ### Claim 20 (depends on 1) Pumping system according to claim 1, characterized in that the auxiliary vacuum pump is made of materials having high chemical resistance to substances and gases commonly used in the semi-conductor industry. ### Claim 21 (depends on 1) Pumping method by means of a pumping system according to claim 1, characterized in that the main vacuum pump is started up in order to pump the gases contained in the vacuum chamber and to discharge these gases through its gas discharge outlet; simultaneously the auxiliary vacuum pump is started up; and the auxiliary vacuum pump continues to pump all the while that the main vacuum pump pumps the gases contained in the vacuum chamber and/or all the while that the main vacuum pump maintains a defined pressure in the vacuum chamber. ### Claim 22 (depends on 21) Pumping method according to claim 21, characterized in that the auxiliary vacuum pump pumps a flow rate on the order of 1/500 to 1/20 of the nominal flow rate of the main vacuum pump. ### Claim 23 (depends on 22) Pumping method according to claim 22, characterized in that the non-return valve closes when the pressure at the suction end of the main vacuum pump is less than 500 mbar absolute. ### Claim 24 (depends on 21) Pumping method according to claim 21, characterized in that the auxiliary vacuum pump is an ejector. ### Claim 25 (depends on 24) Pumping method according to claim 24, characterized in that the flow of gas at the pressure necessary for the operation of the ejector is provided by a compressor. ### Claim 26 (depends on 25) Pumping method according to claim 25, characterized in that the compressor is driven by the main pump. ### Claim 27 (depends on 25) Pumping method according to claim 25, characterized in that the compressor is driven autonomously, independently of the main pump.