a quick connect coupling for removably joining two pipes includes an upstream element and a downstream element adapted to be fitted axially with the upstream element thereby opening a valve movable between a position of opening and a position of closure . the upstream element is provided with at least one o - ring disposed to surround the valve and is adapted for connection to an upstream pipe for inlet of pressurized gas , particularly oxygen . a primary sealing zone is provided upstream of the o - ring which is dimensioned to induce a significant reduction in a flowrate of gas flowing in the direction of the o - ring in order to limit overheating of the o - ring .