Redundant seal ball valve

Claim 1

A ball valve comprising: a valve body, having a throughflow passage therein with inlet and outlet ports, comprising first and second separable sections joined via mating end portions coaxially disposed with respect to said passage, and having an annular seal retaining recess formed in the outer periphery of one of said end portions and closed by the facing interior wall of the other of said end portions; a resilient O-ring disposed within said seal retaining recess thereby providing a fluid-tight junction between said first and second separable sections; a hollow thin-walled valve ball, having an outer spherically curved wall and an interiorly disposed cylindrical sleeve defining a flow conduit extending centrally through said ball and joined at its ends to said outer wall, said ball being rotatable on a diametral axis within said passage between an open position, wherein the flow conduit through said ball is coaxially aligned and communicates with said inlet and outlet ports, and a closed position wherein said flow conduit is transversely positioned with respect to said inlet and outlet ports; selectively engageable shaft coupling means disposed on one side of said outer wall of said valve ball for rotation therewith; a rotatable shaft accessible externally of, and journalled in, one wall of said second section of said valve body on a diametral axis of said ball normal to the plane of rotation of said ball passage axis, said shaft having an annular sealreceiving groove therein at a location adjoining the journalled portion of said valve body wall; a resilient shaft seal ring disposed in a fluid-tight relationship in said seal-receiving groove of said shaft; a non-circular head on the inner end of said shaft selectively engageable with said coupling means for rotation of said ball by said shaft; inlet and outlet seals carried by said first and second separable sections, respectively, and disposed about said inlet and outlet ports, respectively, in fluid sealing engagement with said valve ball, said seals engAging the exterior surface of said ball in surrounding relation to the ends of said flow conduit when said ball valve is in the open position, and in circumferentially spaced relation to said flow conduit ends when said ball is in the closed position; and said inlet seal including a resilient wiper ring having an annular wiping surface engaging said valve ball surface and a concentric annular seal groove therein entering said wiping surface between the radially inner and outer circumferential edges of said wiping surface so as to provide said wiper ring with a radially inner wiping face between said groove and inner edge, and a resilient seal ring carried within said seal groove and engaging said valve ball surface, said seal ring being softer and more resiliently compliant than said wiping face of said wiper ring, and said wiping face engaging said valve ball surface between said inlet port and seal ring to shield said seal ring against contact with any solid objects entering said valve.