Control valve

Claim 1

A VALVE BODY MEMBER HAVING AN INLET AT ONE END, AN OUTLET AT THE OTHER, AND AN INTERMEDIATE LONGITUDINALLY DISPOSED BORE, A TUBULAR MEANS COAXIAL WITH SAID BORE, FIXED WITH SAID BODY MEMBER AND HAVING A LATERAL THROTTLING PORT COMMUNICATING WITH SAID OUTLET, A THROTTLING SLEEVE MEMBER TELESCOPICALLY SLIDABLE RELATIVE TO SAID TUBULAR MEANS AND HAVING A PORTION VARYING THE EFFECTIVE SIZE OF SAID PORT, A WALL MEMBER ACROSS SAID SLEEVE MEMBER EXPOSED TO FLUID FROM SAID INLET, AN ENLARGED HEAD ON THE INLET END OF SAID SLEEVE MEMBER PRESENTING A SEAT FACING TOWARD THE VALVE OUTLET, AN ANNULAR PISTON MEMBER SLIDABLY FITTED IN SAID BORE, SAID PISTON MEMBER HAVING A SEATING SURFACE ENGAGEABLE WITH SAID SEAT ON SAID HEAD OF SAID SLEEVE MEMBER, ABUTMENT MEANS ON SAID BODY MEMBER PROVIDING A STOP FOR SAID PISTON MEMBER IN MOVEMENT TOWARD SAID INLET, A COIL COMPRESSION SPRING IN SAID BODY MEMBER URGING SAID PISTON MEMBER IN THE DIRECTION OF SAID FIRST-MENTIONED ABUTMENT MEANS, AND A SECOND ABUTMENT MEANS ON SAID BODY MEMBER PROVIDING A STOP FOR SAID SLEEVE MEMBER IN MOVEMENT TOWARD SAID INLET WHEN SAID SEAT ON SAID HEAD HAS SEPARATED FROM SAID SEATING SURFACE ON SAID PISTON MEMBER WITH SAID PISTON MEMBER IN ENGAGEMENT WITH SAID FIRST-MENTIONED ABUTMENT MEANS, THERE BEING, IN AT LEAST ONE OF SAID MEMBERS, A FLUID PASSAGEWAY WITH AN ORIFICE THEREIN PROVIDING COMMUNICATION BETWEEN SAID INLET AND SAID BORE ON THE OUTLET SIDE OF SAID PISTON MEMBER, SAID SECOND ABUTMENT MEANS AND SAID SLEEVE MEMBER BEING COOPERATIVELY FORMED TO AFFORD, WHEN IN ENGAGEMENT A FLUID PASSAGE BETWEEN SAID INLET AND THE SPACE BETWEEN THE THEN SEPARATED SEAT ON SAID HEAD AND SEATING SURFACE ON SAID PISTON MEMBER, AT LEAST ONE OF SAID PISTON AND SLEEVE MEMBER BEING FORMED TO PROVIDE A FLUID PASSAGE FROM SAID BORE ON THE OUTLET SIDE OF SAID PISTON MEMBER PAST SAID PISTON MEMBER AND THE HEAD OF SAID SLEEVE MEMBER, RADIALLY INWARD OF SAID SEAT ON SAID HEAD.