Valve for a gas vessel

A valve for a gas source containing gas under pressure, the valve comprising:

• a valve housing having a closure valve chamber formed therein;
• a gas-pressure line formed in said valve housing for conducting use gas from the gas vessel into said valve chamber;
• a gas-takeoff line communicating directly with said chamber for directing gas away from said closure valve chamber and said valve housing;
• closure valve means for interrupting the flow of the use gas from said gas-pressure line, said closure valve means including:
• valve seat means on a wall of said chamber;
• a valve closure body mounted inside of said chamber so as to be movable between a first position inside of said chamber wherein said gas-pressure line communicates with said chamber to permit use gas to flow into said chamber and to said gas-takeoff line and a second position also inside of said chamber wherein said valve closure body is in sealing contact engagement with said valve seat means and the flow of use gas into said valve chamber is interrupted;
• and, actuator means for acting on said valve body at a location thereon facing away from said valve seat means to move said valve body from said first position to said second position;
• a purging gas conduit for conducting purging gas into said closure valve chamber, said purging gas conduit being in permanent communication with said gas-takeoff line via said chamber independently of said positions of said closure valve body thereby permitting the purging gas to pass directly through said valve chamber to said gas-takeoff line thereby throughly purging said chamber and the region of said valve means;
• and,
• purging valve means for passing and interrupting the flow of purging gas to said closure valve chamber via said purging gas conduit.