Pumping method in a system for pumping and system of vacuum pumps

Abstract

The present invention relates to a pumping method in a pumping system (SP, SPP) comprising: a primary lubricated rotary vane vacuum pump ( 3 ) with a gas inlet port ( 2 ) connected to a vacuum chamber ( 1 ) and a gas outlet port ( 4 ) leading into a conduit ( 5 ) before coming out into the gas outlet ( 8 ) of the pumping system (SP, SPP), a non-return valve ( 6 ) positioned in the conduit ( 5 ) between the gas outlet port ( 4 ) and the gas outlet ( 8 ), and an ejector ( 7 ) connected in parallel to the non-return valve ( 6 ). According to this method, the primary lubricated rotary vane vacuum pump ( 3 ) is set into action in order to pump the gases contained in the vacuum chamber ( 1 ) through the gas outlet port ( 4 ). Simultaneously the ejector ( 7 ) is fed with working fluid, and the ejector ( 7 ) continues to be fed with working fluid all the while that the primary lubricated rotary vane vacuum pump ( 3 ) pumps the gases contained in the vacuum chamber ( 1 ) and/or all the while that the primary lubricated rotary vane vacuum pump ( 3 ) maintains a defined pressure in the vacuum chamber ( 1 ). The present invention also relates to a pumping system (SP, SPP) able to be used to implement this method.

1 . Pumping method in a pumping system (SP, SPP) comprising:
 a primary lubricated rotary vane vacuum pump ( 3 ) with a gas inlet port ( 2 ) connected to a vacuum chamber ( 1 ) and a gas outlet port ( 4 ) leading into a conduit ( 5 ) before coming out into the gas outlet ( 8 ) of the pumping system (SP, SPP),   a non-return valve ( 6 ) positioned in the conduit ( 5 ) between the gas outlet port ( 4 ) and the gas outlet ( 8 ), and   an ejector ( 7 ) connected in parallel to the non-return valve ( 6 ),   the method being characterized in that   the primary lubricated rotary vane vacuum pump ( 3 ) is set into action in order to pump the gases contained in the vacuum chamber ( 1 ) through the gas outlet port ( 4 );   simultaneously the ejector ( 7 ) is fed with working fluid; and   the ejector ( 7 ) continues to be fed with working fluid all the while that the primary lubricated rotary vane vacuum pump ( 3 ) pumps the gases contained in the vacuum chamber ( 1 ) and/or all the while that the primary lubricated rotary vane vacuum pump ( 3 ) maintains a defined pressure in the vacuum chamber ( 1 ).   
     
     
         2 . Pumping method according to  claim 1 , characterized in that the outlet of the ejector ( 7 ) rejoins the conduit ( 5 ) after the non-return valve ( 6 ). 
     
     
         3 . Pumping method according to  claim 1  or  2 , characterized in that the ejector ( 7 ) is dimensioned so as to have a minimal consumption of working fluid. 
     
     
         4 . Pumping method according to any one of the  claims 1  to  3 , characterized in that the nominal flow rate of the ejector ( 7 ) is selected depending on the volume of the exit conduit ( 5 ) of the primary lubricated rotary vane vacuum pump ( 3 ) which is limited by the non-return valve ( 6 ). 
     
     
         5 . Pumping method according to  claim 4 , characterized in that the flow rate of the ejector is from 1/500 to 1/20 of the nominal flow rate of the primary lubricated rotary vane vacuum pump ( 3 ). 
     
     
         6 . Pumping method according to any one of the  claims 1  to  5 , characterized in that the working fluid of the ejector ( 7 ) is compressed air and/or nitrogen. 
     
     
         7 . Pumping method according to any one of the  claims 1  to  6 , characterized in that the ejector ( 7 ) is single-staged or multi-staged. 
     
     
         8 . Pumping method according to any one of the  claims 1  to  7 , characterized in that the non-return valve ( 6 ) closes when the pressure at the suction end of the primary lubricated rotary vane vacuum pump ( 3 ) is between 500 mbar absolute and the final vacuum. 
     
     
         9 . Pumping method according to any one of the  claims 1  to  8 , characterized in that the ejector ( 7 ) is made of material having elevated chemical resistance to substances and gases commonly used in the chemical industry and/or the semi-conductor industry. 
     
     
         10 . Pumping method according to any one of the  claims 1  to  9 , characterized in that the ejector ( 7 ) is integrated into a cartridge which incorporates the non-return valve ( 6 ). 
     
     
         11 . Pumping method according to  claim 10 , characterized in that the cartridge itself is accommodated in the oil separator of the primary lubricated rotary vane vacuum pump. 
     
     
         12 . Pumping method according to any one of the  claims 1  to  11 , characterized in that the flow of gas at the pressure necessary for operation of the ejector ( 7 ) is provided by a compressor ( 10 ). 
     
     
         13 . Pumping method according to  claim 12 , characterized in that the compressor ( 10 ) is driven by the primary lubricated rotary vane pump ( 3 ). 
     
     
         14 . Pumping method according to  claim 12 , characterized in that the compressor ( 10 ) is driven autonomously, independently of the primary lubricated rotary vane pump ( 3 ). 
     
     
         15 . Pumping method according to any one of the  claims 12  to  14 , characterized in that the compressor ( 10 ) suctions the atmospheric air or gases in the gas exit conduit ( 8 ) after the non-return valve ( 6 ). 
     
     
         16 . Pumping method according to any one of the  claims 1  to  15 , characterized in that at least one operating parameter is measured and used to start up or stop the ejector ( 7 ). 
     
     
         17 . Pumping method according to  claim 16 , characterized in that the at least one operating parameter is the motor current of the lubricated rotary vane vacuum pump  3 , the pressure of the gases in the space of the exit conduit of the primary lubricated rotary vane vacuum pump limited by the non-return valve  6 , the temperature of the gases in the space of the exit conduit of the primary lubricated rotary vane vacuum pump limited by the non-return valve  6  or a combination of these parameters. 
     
     
         18 . Pumping system (SP, SPP) comprising:
 a primary lubricated rotary vane vacuum pump ( 3 ) with a gas inlet port ( 2 ) connected to a vacuum chamber ( 1 ) and a gas outlet port ( 4 ) leading into a conduit ( 5 ) before coming out into the gas outlet ( 8 ) of the system of vacuum pumps (SP),   a non-return valve ( 6 ) positioned in the conduit ( 5 ) between the gas outlet port ( 4 ) and the gas outlet ( 8 ), and   an ejector ( 7 ) connected in parallel to the non-return valve ( 6 ),   the pumping system (SP, SPP) being characterized in that   the ejector ( 7 ) is arranged to be able to be fed with working fluid all the while that the primary lubricated rotary vane vacuum pump ( 3 ) pumps the gases contained in the vacuum chamber ( 1 ) and/or all the while that the primary lubricated rotary vane vacuum pump ( 3 ) maintains a defined pressure in the vacuum chamber ( 1 ).   
     
     
         19 . Pumping system according to  claim 18 , characterized in that the outlet of the ejector ( 7 ) rejoins the conduit ( 5 ) after the non-return valve ( 6 ). 
     
     
         20 . Pumping system according to  claim 18  or  19 , characterized in that the ejector ( 7 ) is dimensioned so as to have a minimal consumption of working fluid. 
     
     
         21 . Pumping system according to any one of the  claims 18  to  20 , characterized in that the nominal flow rate of the ejector ( 7 ) is selected depending on the volume of the exit conduit ( 5 ) of the primary lubricated rotary vane vacuum pump ( 3 ) which is limited by the non-return valve ( 6 ). 
     
     
         22 . Pumping system according to  claim 21 , characterized in that the flow rate of the ejector is from 1/500 to 1/20 of the nominal flow rate of the primary lubricated rotary vane vacuum pump ( 3 ). 
     
     
         23 . Pumping system according to any one of the  claims 18  to  22 , characterized in that the working fluid of the ejector ( 7 ) is compressed air and/or nitrogen. 
     
     
         24 . Pumping system according to any one of the  claims 18  to  23 , characterized in that the ejector ( 7 ) is single-staged or multi-staged. 
     
     
         25 . Pumping system according to any one of the  claims 18  to  24 , characterized in that the non-return valve ( 6 ) closes when the pressure at the suction end of the primary lubricated rotary vane vacuum pump ( 3 ) is between 500 mbar absolute and the final vacuum. 
     
     
         26 . Pumping system according to any one of the  claims 18  to  25 , characterized in that the ejector ( 7 ) is made of material having elevated chemical resistance to substances and gases commonly used in the chemical industry and/or the semi-conductor industry. 
     
     
         27 . Pumping system according to any one of the  claims 18  to  26 , characterized in that the ejector ( 7 ) is integrated into a cartridge which incorporates the non-return valve ( 6 ). 
     
     
         28 . Pumping system according to  claim 27 , characterized in that the cartridge itself is accommodated in the oil separator of the primary lubricated rotary vane vacuum pump. 
     
     
         29 . Pumping system according to any one of the  claims 18  to  28 , characterized in that the system comprises a compressor ( 10 ) which provides the flow of gas at the pressure necessary for operation of the ejector ( 7 ). 
     
     
         30 . Pumping system according to  claim 29 , characterized in that the compressor ( 10 ) is driven by the primary lubricated rotary vane pump ( 3 ). 
     
     
         31 . Pumping system according to  claim 29 , characterized in that the compressor ( 10 ) is driven autonomously, independently of the primary lubricated rotary vane pump ( 3 ). 
     
     
         32 . Pumping system according to any one of the  claims 29  to  31 , characterized in that the compressor ( 10 ) suctions the atmospheric air or gases in the gas exit conduit ( 8 ) after the non-return valve ( 6 ). 
     
     
         33 . Pumping system according to any one of the  claims 18  to  32 , characterized in that it comprises at least one sensor ( 11 ,  12 ,  13 ) for measuring at least one operating parameter and for using it in order to start up or stop the ejector ( 7 ). 
     
     
         34 . Pumping system according to  claim 34 , characterized in that the at least one operating parameter is the motor current of the lubricated rotary vane vacuum pump  3 , the pressure of the gases in the space of the exit conduit of the primary lubricated rotary vane vacuum pump limited by the non-return valve  6 , the temperature of the gases in the space of the exit conduit of the primary lubricated rotary vane vacuum pump limited by the non-return valve  6  or a combination of these parameters.