Two-Step-Process for Filling Gas Containers for Airbag Systems and Gas Filling Device for a Two-Step-Filling Process

Abstract

The invention concerns a process respectively a device for filling a high pressure gas container ( 1 ), comprising the following steps: Supplying a liquefied or solidified first gas ( 2 ) into a gas container ( 1 ) while the gas container ( 1 ) is being cooled; stopping the cooling of the gas container ( 1 ) after the supplying step of the first gas; then introducing a gaseous second gas ( 3 ) into the gas container ( 1 ) and closing the gas container ( 1 ). The invention allows for a efficient, reproducible, reliable and economical filling of high pressure gas containers ( 1 ), in particular for airbag systems or for fuel cells, and allows to use conventional devices for introducing gases respectively closing gas containers that are not particularly adapted for low temperature respectively high pressure applications.

1 . Process for filling a high pressure gas container ( 1 ), comprising the following steps: supplying a liquefied or solidified first gas ( 2 ) into a gas container ( 1 ) while the gas container ( 1 ) is being cooled; stopping the cooling of the gas container ( 1 ) after the supplying step of the first gas; then introducing a gaseous second gas ( 3 ) into the gas container ( 1 ); closing the gas container ( 1 ). 
   
   
       2 . Process according to  claim 1 , characterized in that the cooling of the gas container ( 1 ) is performed in a cooling bath ( 4 ), in particular a cooling bath 
     ( 4 ) of liquid nitrogen, and the cooling is stopped by disconnecting the gas container ( 1 ) from the cooling bath ( 4 ). 
   
   
       3 . Process according to  claim 1 , characterized in that the first gas ( 2 ) and/or the second gas ( 3 ) is a mixture of plural gases. 
   
   
       4 . Process according to  claim 1 , characterized in that the first gas ( 2 ) and/or the second gas ( 3 ) is an inert gas, in particular a noble gas. 
   
   
       5 . Process according to  claim 1 , characterized in that after the supplying step of the first gas ( 2 ) and before the introducing step of the second gas ( 3 ) the gas container ( 1 ) is temporarily closed. 
   
   
       6 . Process according to  claim 5 , characterized in that the gas container ( 1 ) is temporarily closed using an auxiliary valve ( 5 ). 
   
   
       7 . Process according to  claim 1 , characterized in that the closing of the gas container ( 1 ) is performed by welding. 
   
   
       8 . Process according to  claim 1 , characterized in that the gas containers ( 1 ) are for air bag systems. 
   
   
       9 . Process according to  claim 1 , characterized in that gas containers ( 1 ) are for fuel cells. 
   
   
       10 . Process according to  claim 1 , characterized in that the supplying of the first gas ( 2 ) is performed at a pressure in the range from 0.2 bar to 15 bar, in particular in the range from 0.5 bar to 4 bar. 
   
   
       11 . Process according to  claim 1 , characterized in that the supplying of the second gas ( 3 ) is performed at a pressure in the range from 2 bar to 100 bar, in particular, in the range from 5 bar to 50 bar, for example in the range from 10 bar to 20 bar. 
   
   
       12 . Process according to  claim 1 , characterized in that the first gas ( 2 ) is supplied in a liquid state into the gas container ( 1 ) and solidifies in the gas container ( 1 ). 
   
   
       13 . Process according to  claim 1 , characterized in that the first gas ( 2 ) is supplied at a temperature lower than its boiling temperature, in particular at least 1° K, preferably at least 2° K, lower than its boiling temperature, and at a temperature higher than its freezing temperature, in particular at least 1° K 5  preferably at least 2° K, higher than its freezing temperature. 
   
   
       14 . Process according to  claim 1 , characterized in that after the supplying step of the first gas ( 2 ) and before the introducing step of the second gas ( 3 ), the gas container ( 1 ) is connected to a sealing device ( 11 ), in particular a welding apparatus ( 12 ), and after the introducing step of the second gas ( 3 ) the gas container ( 1 ) is sealed by the sealing device 
     ( 11 ), in particular by welding. 
   
   
       15 . Process according to  claim 1 , characterized in that the cooling is performed using a liquefied third gas ( 6 ), in particular liquid nitrogen, wherein in particular the temperature of the third gas ( 6 ) is controlled by controlling the pressure in the third gas ( 6 ). 
   
   
       16 . Process according to  claim 1 , characterized in that the gas container ( 1 ) is cooled before the supplying step of the first gas ( 2 ). 
   
   
       17 . Device for filling high pressure gas containers ( 1 ), comprising a supplying unit ( 7 ) for supplying a liquefied or solidified first gas ( 2 ) into a gas container ( 1 ) while the gas container ( 1 ) is being cooled; a stopping unit ( 8 ) for stopping the cooling of the gas container ( 1 ); an introducing unit ( 9 ) for introducing a gaseous second gas ( 3 ) into the gas container ( 1 ) after the supplying step of the first gas; a unit ( 10 ) for closing the gas container ( 1 ). 
   
   
       18 . Device according to  claim 17 , further comprising a cooling bath ( 4 ) for cooling the gas container ( 1 ). 
   
   
       19 . Device according to  claim 18 , further comprising a transport mechanism 
     ( 12 ) for transporting the gas containers ( 1 ) through the cooling bath ( 4 ). 
   
   
       20 . Device according to  claim 17 , characterized in that the unit ( 10 ) for closing the gas container ( 1 ) is a welding apparatus ( 12 ). 
   
   
       21 . Device according to  claim 17 , characterized in that the de-vice is for filling high pressure gas containers ( 1 ) for air bag systems or for fuel cells. 
   
   
       22 . Device according to  claim 17 , further comprising a gas supply station ( 13 ) and at least one thermally insulated filling tube ( 14 ) with a tube head ( 15 ) that is in fluid connection with the gas supply station ( 13 ), wherein the filling tube ( 14 ) is for supplying the first gas ( 2 ) to the gas containers ( 1 ). 
   
   
       23 . Device according to  claim 22 , further comprising a positioning device ( 16 ) for positioning the tube head ( 15 ) at the gas containers ( 1 ).