Sealed flange joint for high pressure and high purity gas channels

A sealed flange joint for fluid channels comprising:

• a first flange with a first fluid channel and a cylindrical front cavity, said front cavity being axially delimited by a ground surface and radially by a peripheral surface, said first fluid channel axially passing through said first flange to open into said ground surface of said front cavity;
• a polymer seal ring having a radial outer surface and a radial inner surface, said seal ring being fitted into said cylindrical front cavity so that its radial outer surface engages said peripheral surface of said front cavity;
• and
• a second flange with a second fluid channel passing through said second flange in axial continuation of said first fluid channel, and an axially protruding cylindrical front nipple with a conical head, said second fluid channel axially opening into an end surface of said conical head, wherein said first and second flange are removably fixed to each other;
• wherein said first flange and said nipple delimit a seal ring chamber in said cylindrical front cavity;
• said seal ring, in a compressed state, having substantially the same cross-sectional shape as said seal ring chamber;
• wherein said conical head engages and delimits said radial inner surface of said polymer seal ring to radially press the latter with its radial outer surface against said peripheral surface of said front cavity;
• and
• wherein said first flange comprises an axially protruding positioning head forming a first axial abutment surface surrounding said cylindrical front cavity, said second flange comprises a positioning cavity forming a second axial abutment surface that surrounds said nipple such that said nipple is arranged therein, said first and second abutment surfaces being axially pressed one against the other, said positioning cavity being configured to receive and radially position said axially protruding positioning head;
• wherein a small gap separates said end surface of said conical head of said nipple from said ground surface of said front cavity when said first and second abutment surfaces have been axially pressed one against the other;
• and
• wherein said nipple has a height that is smaller or equal to the depth of said positioning cavity.