Blast valve structure for an electrical circuit breaker

Claim 1

IN A COMBINED PNEUMATIC CIRCUIT BREAKER AND BLAST VALVE STRUCTURE THE COMBINATION COMPRISING A GAS-PRESSURIZED CHAMBER WITHIN WHICH IS LOCATED A STATIONARY TUBULAR CONTACT MEMBER AND A TUBULAR MOVABLE CONTACT STRUCTURE COAXIAL WITH SAID STATIONARY TUBULAR MEMBER AND ADAPTED FOR MOVEMENT LONGITUDINALLY OF ITSELF INTO AND OUT OF ENGAGEMENT WITH SAID STATIONARY TUBULAR CONTACT MEMBER, AND A BLAST VALVE SEALING OFF COMMUNICATION BETWEEN SAID CHAMBER AND THE INTERIOR OF SAID STATIONARY TUBULAR CONTACT MEMBER WHEN SAID CONTACT MEMBERS ARE ENGAGED, SAID BLAST VALVE INCLUDING A TUBULAR VALVE MEMBER FORMING PART OF SAID MOVABLE CONTACT STRUCTURE AND THE END FACE OF WHICH SERVES AS A MOVABLE VAVLE SEAT ARRANGED TO STRIKE AGAINST A STATIONARY ANNULAR SEALING MEANS SURROUNDING AND SUPPORTED BY A LATERAL SURFACE ON SAID STATIONARY TUBULAR CONTACT MEMBER, SAID SEALING MEANS BEING CONSTITUTED BY TWO ANNULAR SUPERIMPOSED HARD AND SOFT SEALING DISCS, SAID HARD SEALING DISC BEING STRIKABLE BY THE END FACE OF SAID MOVABLE TUBULAR VALVE MEMBER TO EFFECT A CLOSING OF SAID BLAST VALVE AND BEING MADE FROM POLYTETRAFLUOROETHYLENE REINFORCED WITH GLASS FIBERS AND SAID SOFT DISC BEING MADE FROM A SILICONE RUBBER.