Pressure-loaded cylinder valve insert

Claim 1

A valve insert adapted to be removably mounted as a unit on one fluid conduit to selectively enable a flow of fluid therethrough when another fluid conduit is sufficiently engaged therewith and to prevent such fluid flow when such conduits are physically separated from one another, comprising: a tubular body adapted to be sealingly mounted on said one fluid conduit, said body having an opening through which fluid may flow, having an annular seat surrounding said opening and facing toward the normal direction of fluid flow, having an abutment surface facing away from the normal direction of fluid flow, and having an inwardly-facing surface; a valve member mounted on said body for movement relative thereto, said valve member having a resilient seal mounted for movement toward and away from said seat to define a variable-area orifice through which fluid may flow, said member being movable relative to said body to any position between one position at which said orifice area is a maximum and another position at which said orifice area is zero, said member having an abutment surface arranged to face said body abutment surface and having an outwardly-facing surface arranged to slidably engage said body inwardly-facing surface, the joint between said inwardly- and outwardly-facing surfaces being sealed at all relative positions between said member and body; biasing means acting between said body and member abutment surfaces for continuously urging said seal to move toward said seat; a docking member mounted on said member and adapted to engage said other fluid conduit; and coupling means for selectively holding said first and second conduits together with said other conduit engaged with said insert; whereby when said conduits are separated, pressure differential across said insert will act across a first area to urge said seal into tighter sealed engagement with said seat, and when said other conduit is engaged with said insert and displaces said seal off said seat, a pressure differential across said insert will act across a second area to urge said docking member into fluid-tight sealed engagement with said other conduit independent of the specific position of said member relative to said body.