| 摘要 |
The conical pre-sealing ring (30) is intended to provide temporary sealing while the appliance (20) is being screwed into or unscrewed from the valve (10) of a gas cylinder. Deep penetration of the push-element (21) of the appliance (20) can cause the conical pre-sealing ring (30) to reverse and remain in this position, even after unscrewing. According to the invention, to overcome this drawback, the conical pre-sealing ring (30) is provided with radial protuberances (33) which prevent gas-tight contact between the reversed surface of the conical pre-sealing ring (30) and the valve shoulder (16). This ensures that the space (40) always remains in communication with the gas pressure, so that, on dismantling, the sealing ring is returned to its initial position by a purely pneumatic effect. |
