Rapidly pumping out an enclosure while limiting energy consumption

Abstract

A vacuum pumping device of the invention comprises a motor ( 1 ) driving a multi-stage dry mechanical pump ( 2 ) in which the stages ( 5, 6, 7, 8 ) are connected successively in parallel and then in series in a plurality of successive configurations, each of which is selected to optimize the pumping speed in the current pressure range. This makes it possible to lower pressure inside an enclosure ( 100 ) quickly while reducing the volume of the pump and the energy consumed by the pump by about 40% compared with a traditional pump having a speed that is sufficient to obtain the same rapidity of pumping.

1 . A vacuum pumping device for lowering the pressure of an enclosure ( 100 ), the device comprising a motor ( 1 ) driving a multi-stage dry mechanical vacuum pump ( 2 ), each stage ( 5 - 8 ) having an intake ( 5   c - 8   c ) and an outlet ( 5   d - 8   d ), and the pump including pipes ( 9 - 11 ) for interconnecting the stages ( 5 - 8 ) in the circuit for pumping gas out from the enclosure, the device being characterized in that it includes fluid flow connection means ( 12 - 19 ) that interconnect the stages ( 5 - 8 ) so as to pass from a first configuration in which the stages are connected in parallel at least in pairs during a first pumping step (E 1 ), to a last configuration in which the stages are connected in series in a last pumping step (E 3 ), and passing via at least one intermediate configuration, during an intermediate pumping step (E 2 ), pumping speed being optimized in each current pressure range, and in which at least one stage ( 5 ) is connected in parallel with at least one other stage ( 6 ), while at least one stage ( 7 ) is connected in series with at least one other stage ( 8 ).  
   
   
       2 . A device according to  claim 1 , in which the fluid flow connection means ( 12 - 19 ) comprise valves ( 16 - 19 ) controlled by electronic control means ( 22 ) and inserted in the pipes ( 9 ,  11 ,  13 ,  15 ).  
   
   
       3 . A device according to  claim 2 , in which the electronic control means ( 22 ) actuate the valves ( 16 - 19 ) to pass from one configuration to the following configuration in response to variation in the gas pressure inside the enclosure ( 100 ).  
   
   
       4 . A device according to  claim 2 , in which the electronic control means ( 22 ) actuate the valves ( 16 - 19 ) to pass from one configuration to the following configuration in response to variation in the power consumed by the motor ( 1 ) of the pump.  
   
   
       5 . A device according to  claim 2 , in which the electronic control means ( 22 ) actuate the valves ( 16 - 19 ) to pass from one configuration to the following configuration after a predefined duration.  
   
   
       6 . A device according to  claim 2 , in which the valves ( 16 - 19 ) and the inter-stage pipes ( 9 - 11 ) are integrated in the body of the vacuum pump ( 2 ).  
   
   
       7 . A device according to  claim 2 , in which, in the last pumping step (E 3 ), the electronic control means ( 22 ) increase the velocity of the motor ( 1 ).  
   
   
       8 . A device according to  claim 2 , in which, when the desired pressure state is reached inside the enclosure ( 100 ), the electronic control means ( 22 ) reduce the velocity of rotation of the motor ( 1 ) to provide pressure-maintaining pumping.  
   
   
       9 . A device according to  claim 2 , in which, when the desired pressure state is reached inside the enclosure ( 100 ), the electronic control means ( 22 ) connect an additional low-speed pumping stage to the outlet ( 4 ) in order to maintain pressure.  
   
   
       10 . A device according to  claim 1 , comprising four stages ( 5 - 8 ) connected in the following successive configurations during pumping: 
 a) in a first configuration, during a first pumping step (E 1 ), the first and second stages ( 5 ,  6 ) are connected in parallel with each other forming a first pair of stages, the third and fourth stages ( 7 ,  8 ) are connected in parallel with each other forming a second pair of stages, and the two pairs of stages ( 5 - 6  and  7 - 8 ) are connected in series on the gas-flow path;    b) in a second configuration, during an intermediate pumping step (E 2 ), the first and second stages ( 5 ,  6 ) remain connected in parallel with each other, the third and fourth stages ( 7 ,  8 ) are connected in series with each other, and the first pair of stages comprising the first and second stages are connected in series with the second pair of stages ( 7 - 8 ) comprising the third and fourth stages; and    c) in a third configuration, during a last pumping step (E 3 ), all four stages ( 5 - 8 ) are connected in series with one another.    
   
   
       11 . A device according to  claim 1 , comprising five stages ( 102 ,  103 ,  104 ,  107 ,  108 ) connected in the following successive configurations during pumping: 
 a) in a first configuration, during a first pumping step (E 1 ), the first, second, and third stages ( 102 ,  103  and  104 ) are connected in parallel forming a group of stages ( 102 - 104 ), the fourth and fifth stages ( 107 - 108 ) are connected in parallel with each other, forming a pair of stages ( 107 - 108 ), and the group of stages ( 102 - 104 ) and the pair of stages ( 107 - 108 ) are connected in series with each other on the gas-flow path;    b) in a second configuration, during a first intermediate pumping step (E 2 ), the first and second stages ( 102 ,  103 ) are connected in parallel with each other, forming a first pair of stages ( 102 - 103 ), the third and fourth stages ( 104 - 107 ) are connected in parallel with each other, forming a second pair of stages ( 104 - 107 ), and the first and second pairs of stages ( 102 - 103  and  104 - 107 ) are connected in series with each other and with the fifth stage ( 108 );    c) in a third configuration, during a second intermediate pumping step (E 3 ), the first and second stages ( 102 ,  103 ) are connected in parallel with each other forming a pair of stages ( 102 - 103 ), and the third, fourth, and fifth stages ( 104 ,  107 ,  108 ) are connected in series with one another, and with the pair of stages ( 102 - 103 ); and    d) in a fourth configuration, during a last pumping step (E 4 ), all five stages ( 102 ,  103 ,  104 ,  107 ,  108 ) are connected in series with one another.    
   
   
       12 . A device according to  claim 1 , comprising six stages ( 202 ,  203 ,  204 ,  207 ,  208 ,  209 ) connected in the following successive configurations during pumping: 
 a) in a first configuration, during a first pumping step (E 1 ), the first, second, and third stages ( 202 ,  203  and  204 ) are connected in parallel forming a first group of stages ( 202 - 204 ), the fourth, fifth, and six stages ( 207 ,  208 ,  209 ) are connected in parallel forming a second group of stages ( 207 - 209 ), and the first and second groups of stages ( 202 - 204  and  207 - 209 ) are connected in series with each other on the gas-flow path;    b) in a second configuration, during a first intermediate pumping step (E 2 ), the first, second, and third stages ( 202 ,  203 ,  204 ) are connected in parallel forming a group of stages ( 202 - 204 ), the third and fourth stages ( 207 ,  208 ) are connected in parallel with each other, forming a pair of stages ( 207 - 208 ), and the group of stages ( 202 - 204 ) and the pair of stages ( 207 - 208 ) are connected in series with each other, and with the sixth stage ( 209 );    c) in a third configuration, during a second intermediate pumping step (E 3 ), the first, second, and third stages ( 202 ,  203 ,  204 ) are connected in parallel forming a group of stages ( 202 - 204 ), and the fourth, fifth, and sixth stages ( 207 ,  208 ,  209 ) are connected in series with one another, and with the group of stages ( 202 - 204 );    d) in a fourth configuration, during a third intermediate pumping step (E 4 ), the first and second stages ( 202 ,  203 ) are connected in parallel with each other forming a pair of stages ( 202 - 203 ), and the third, fourth, fifth, and sixth stages ( 204 ,  207 ,  208 , and  209 ) are connected in series with one another, and with the pair of stages ( 202 - 203 ); and    e) in a fifth configuration, during a last pumping step (E 5 ), all six stages ( 202 ,  203 ,  204 ,  207 ,  208 ,  209 ) are connected in series with one another.    
   
   
       13 . A device according to any one of  claims 1  to  9   claim 1 , comprising six stages ( 302 ,  303 ,  304 ,  307 ,  310 ,  311 ) connected in the following successive configurations during pumping: 
 a) in a first configuration, during a first pumping step (E 1 ), the first, second, and third stages ( 302 ,  303 ,  306 ) are connected in parallel forming a first group of stages ( 302 - 306 ), the fourth, fifth, and six stages ( 307 ,  310 ,  311 ) are connected in parallel forming a second group of stages ( 307 - 311 ), and the first and second groups of stages ( 302 - 306  and  307 - 311 ) are connected in series on the gas-flow path;    b) in a second configuration, during a first intermediate pumping step (E 2 ), the first and second stages ( 302 ,  303 ) are connected in parallel with each other forming a first pair of stages ( 302 - 303 ), the third and fourth stages ( 306 ,  307 ) are connected in parallel with each other forming a second pair of stages ( 306 - 307 ), the fifth and sixth stages ( 310 ,  311 ) are connected in parallel with each other forming a third pair of stages ( 310 - 311 ), and the first, second, and third pairs of stages ( 302 - 303 ,  306 - 307 , and  310 - 311 ) are connected in series with one another;    c) in a third configuration, during a second intermediate pumping step (E 3 ), the first and second stages ( 302 ,  303 ) are connected in parallel with each other forming a first pair of stages ( 302 - 303 ), the third and fourth stages ( 306 ,  307 ) are connected in parallel with each other forming a second pair of stages ( 306 - 307 ), and the fifth and sixth stages ( 310 - 311 ) are connected in series with each other, and with the first and second pairs of stages ( 302 - 303 ,  306 - 307 );    d) in a fourth configuration, during a third intermediate pumping step (E 4 ), the first and second stages ( 302 ,  303 ) are connected in parallel with each other forming a pair of stages ( 302 - 303 ), and the third, fourth, fifth, and sixth stages ( 303 ,  307 ,  310 ,  311 ), are connected in series with one another, and with the pair of stages ( 302 - 303 ); and    e) in a fifth configuration, during a last pumping step (E 5 ), all six stages ( 302 ,  303 ,  306 ,  307 ,  310 ,  311 ) are connected in series with one another.    
   
   
       14 . A vacuum pumping method using a multi-stage dry mechanical pump ( 2 ) for lowering the pressure inside an enclosure, in which the stages ( 5 - 8 ) of the pump ( 2 ) are interconnected in a plurality of successive configurations to pass from a first configuration in which the stages are connected in parallel at least in pairs during a first pumping step (E 1 ) to a last configuration in which the stages are connected in series during a last pumping step (E 3 ), and passing via at least one intermediate configuration (E 2 ), each configuration being selected to optimize pumping speed in the current pressure range, and in which in the or each intermediate configuration at least one intake stage ( 5 ) is connected in parallel with at least one other intake stage ( 6 ) and at least one outlet stage ( 7 ) is connected in series with at least one other stage ( 8 ).  
   
   
       15 . A method according to  claim 14 , in which, during the last pumping step, the velocity of the pump is temporarily increased above its nominal velocity.