Gate valve with replaceable liner

Claim 1

A gate valve having a positionable gate disposed therein for regulating the flow of fluid intermediate an attached pair of pipes, said gate valve comprising: a. a gate having opposing surfaces and being positionable within said gate valve for effecting regulation of the flow of fluid; b. a pliant liner molded in one piece for receiving, guiding and seating said gate, said liner including i. a chest having a gate passageway with opposing sidewalls spaced from the opposing surfaces of the gate disposed therebetween; ii. a ring defining a bore and extending downwardly from said chest in general planar alignment therewith; iii. a depression disposed within said bore for defining a seat for said gate; iv. first seal means disposed near the bottom of the opposing sidewalls within said chest and being in sealing contact with the gate for preventing a flow of fluid through said gate passageway intermediate said chest and said gate; and v. further seal means disposed within said depression for preventing a flow of fluid through the bore of said ring on seating of said gate within said depression; c. a pair of castings for receiving said liner, each of said castings including i. a bore for receiving a part of said ring; ii. a recess for receiving a part of said chest; and iii. attachment means for securing said pair of castings to one another to at least partially enclose said liner therebetween; whereby, said liner negates the need for segregable elements to effect guiding, seating and sealing of said gate within said gate valve.