Container and method for maintaining stability of gas mixtures

Abstract

A container for holding a single constituent gas or a mixture of constituent gases is disclosed. The container has a wall structure defining an internal space. An opening in the wall structure permits access to the internal space. A closure is positioned over the opening. A seal attaches the closure to the wall structure maintains the single constituent gas or the constituents of the gas mixture at a predetermined concentration over a predetermined time period. A valve is mounted on the closure for permitting controlled release of the mixture. A method of maintaining gas concentration stability by forming a seal between the closure and the wall structure is also disclosed.

1 . A container for holding a mixture of a plurality of constituent gases, said gases having respective predetermined concentrations within said mixture, said container comprising:
 a vessel having a wall structure defining an internal space for containing said gas mixture, said wall structure having an opening therein for access to said internal space;   a closure positioned in overlying relation with said opening, a seal for attaching said closure to said wall structure so as to maintain a first one of said gases at a concentration within a range of about +1% to about −7% of said predetermined concentration of said first gas over about a one month period; and   a valve mounted on said closure, said valve being openable and closable for permitting controlled release of said gas mixture from said vessel.   
   
   
       2 . A container according to  claim 1 , wherein said first gas is maintained at a concentration within a range of about +1% to about −5% of said predetermined concentration of said first gas over about a one month period. 
   
   
       3 . A container according to  claim 1 , wherein a second one of said gases is maintained at a concentration within a range of about +3% to about −15% of said predetermined concentration of said second gas over about a one month period. 
   
   
       4 . A container according to  claim 1 , wherein said second gas is maintained at a concentration within a range of about +3% to about −30% of said predetermined concentration of said second gas over about a one month period. 
   
   
       5 . A container according to  claim 1 , wherein a third one of said gases is maintained at a concentration within a range of about +3% to about −15% of said predetermined concentration of said third gas over about a one month period. 
   
   
       6 . A container according to  claim 1 , wherein said third gas is maintained at a concentration within a range of about +3% to about −30% of said predetermined concentration of said third gas over about a one month period. 
   
   
       7 . A container according to  claim 1 , wherein said seal comprises a weld integrally joining said closure to said wall structure. 
   
   
       8 . A container according to  claim 7 , wherein said weld is formed by means of an electron beam. 
   
   
       9 . A container for holding a mixture of a plurality of constituent gases, said gases having respective predetermined concentrations within said mixture, said container adapted to maintain the concentrations of said gases within a predetermined concentration range over a predetermined time period, said container comprising:
 a vessel having a wall structure defining an internal space for containing said gas, said wall structure comprising a metal having the property of being inert with respect to the constituent gases and having an opening therein for access to said internal space;   a closure positioned in overlying relation with said opening, a seal for attaching said closure to said wall structure, said closure and said seal having the same properties of being inert to the constituent gases as said wall structure; and   a valve mounted on said closure, said valve being openable and closable for permitting controlled release of said gas mixture from said vessel.   
   
   
       10 . A container according to  claim 9 , wherein said seal comprises a weld integrally joining said closure to said wall structure. 
   
   
       11 . A container according to  claim 10 , wherein said weld maintains a first one of said gases at a concentration within a range of about +1% to about −5% of said predetermined concentration of said first gas over about a one month period. 
   
   
       12 . A container according to  claim 10 , wherein said weld maintains a first one of said gases at a concentration within a range of about +1% to about −7% of said predetermined concentration of said first gas over about a one month period. 
   
   
       13 . A container according to  claim 11 , wherein said weld maintains a second one of said gases at a concentration within a range of about +3% to about −15% of said predetermined concentration of said second gas over about a one month period. 
   
   
       14 . A container according to  claim 11 , wherein said weld maintains a second one of said gases at a concentration within a range of about +3% to about −30% of said predetermined concentration of said second gas over about a one month period. 
   
   
       15 . A container according to  claim 11 , wherein said weld maintains a third one of said gases at a concentration within a range of about +3% to about −15% of said predetermined concentration of said third gas over about a one month period. 
   
   
       16 . A container according to  claim 11 , wherein said weld maintains a third one of said gases at a concentration within a range of about +3% to about −30% of said predetermined concentration of said third gas over about a one month period. 
   
   
       17 . A container according to  claim 10 , wherein said weld is formed by means of an electron beam. 
   
   
       18 . A container according to  claim 10 , wherein said vessel comprises a thin-walled aluminum cylinder, said opening being positioned at one end thereof. 
   
   
       19 . A container according to  claim 18 , further comprising an outwardly turned lip surrounding said opening, said closure comprising a flange extending around its perimeter, said weld integrally joining said flange and said lip. 
   
   
       20 . A container according to  claim 19 , wherein said flange comprises a perimeter having a curvature matched to the curvature of said lip. 
   
   
       21 . A container according to  claim 10 , wherein said weld maintains a more reactive one of said gases at a concentration within a range of about +1% to about 5% of said predetermined concentration of said more reactive gas over about a one month period. 
   
   
       22 . A container according to  claim 10 , wherein said weld maintains a more reactive one of said gases at a concentration within a range of about +1% to about −7% of said predetermined concentration of said first gas over about a one month period. 
   
   
       23 . A container according to  claim 21 , wherein said weld maintains a less reactive one of said gases at a concentration within a range of about +3% to about −15% of said predetermined concentration of said less reactive gas over about a one month period. 
   
   
       24 . A container according to  claim 21 , wherein said weld maintains a less reactive one of said gases at a concentration within a range of about +3% to about −30% of said predetermined concentration of said less reactive gas over about a one month period. 
   
   
       25 . A container for holding a single constituent gas, said gas having a predetermined concentration of impurities upon filling, said container comprising:
 a vessel having a wall structure defining an internal space for containing said gas, said wall structure having an opening therein for access to said internal space;   a closure positioned in overlying relation with said opening, a seal for attaching said closure to said wall structure so as to maintain said impurities at a concentration within a range of about +1% to about −1% of said predetermined concentration of said impurities upon filling over about a one month period; and   a valve mounted on said closure, said valve being openable and closable for permitting controlled release of said gas mixture from said vessel.   
   
   
       26 . A method of maintaining gas concentration stability among constituent gases of a gas mixture within a predetermined concentration variation range and over a predetermined time period, said method comprising the steps of:
 providing a vessel for holding said gas mixture under pressure, said vessel having an opening therein;   providing a closure adapted to engage said vessel in overlying relation with said opening, said closure having a valve mounted thereon for permitting controlled filling and release of said gas mixture to and from said vessel; and   forming a seal between said closure and said vessel, said seal, said closure and said vessel having the property of being inert with respect to the constituent gases, said seal providing a fluid tight joint between said closure and said vessel that maintains a first one of said gases at a concentration of about +1% to about −5% of a predetermined concentration of said first gas over about a one month period.   
   
   
       27 . A method according to  claim 26 , further comprising the step of forming a seal that maintains said first one of said gases at a concentration within a concentration of about +1% to about −7% of said predetermined concentration of said first gas over about a one month period. 
   
   
       28 . A method according to  claim 26 , further comprising the step of forming a seal that maintains a second one of said gases at a concentration within a range of about +3% to about −15% of said predetermined concentration of said second gas over about a one month period. 
   
   
       29 . A method according to  claim 26 , further comprising the step of forming a seal that maintains a second one of said gases at a concentration of about +3% to about −30% of said predetermined concentration of said second gas over about a one month period. 
   
   
       30 . A method according to  claim 26 , further comprising the step of forming a seal that maintains a third one of said gases at a concentration within a range of about +3% to about −15% of said predetermined concentration of said third gas over about a one month period. 
   
   
       31 . A method according to  claim 26 , further comprising the step of forming a seal that maintains a third one of said gases at a concentration of about +3% to about −30% of said predetermined concentration of said third gas over about a one month period. 
   
   
       32 . A method according to  claim 26 , wherein said seal is formed by the step of electron-beam welding said closure to said vessel. 
   
   
       33 . A method according to  claim 26 , further comprising the step of filling said container with said gas mixture. 
   
   
       34 . A method according to  claim 33 , wherein said filing step comprises filling said container with a gas mixture comprising bromopentafluorobenzene, trifluoromethyl benzene and nitrogen.