Valve, namely for bottles for ultra-high purity gas

Valve for bottles of pressurised or liquefied gas, comprising:

• a valve body comprising a gas flow channel;
• a first sealing seat in said gas flow channel;
• an obturating member having a free end provided with a shoulder;
• an annular seal mounted on said free end of the obturating member, said annular seal having a front end face facing said first seat and a rear end face resting on said shoulder of said obturating member;
• wherein said free end of said obturating member comprises a radial end projection penetrating radially into an internal annular shoulder of said annular seal, said free end being tapered, narrowing from said shoulder in the direction of said radial projection;
• a holding ring circumferentially surrounding said annular seal and comprising a radial lip that bears on the outer edge of said front end face of said annular seal;
• said obturating member being able to be moved axially towards said first seat into a first sealing position, in which said annular seal is pressed against said first seat such that it ensures the main gas-tightness of the valve;
• wherein
• said annular seal comprises an external annular shoulder encircling its front end face;
• said radial lip of said holding ring carries an axially protruding annular bead facing said external annular shoulder of said annular seal;
• and
• said holding ring is fixed to the obturating member by an external circumferential gas-tight weld, such that said annular bead penetrates axially into said external annular shoulder of said annular seal to compress it.