Abstract: A gate valve includes a pair of identically shaped tapered discs defining a tapered self-locking axially translatable gate wherein each disc has an annular hardened seating surface which engages the mating surfaces on the valve body adjacent the flow ports. Tongues on the sides of the discs ride in vertical grooves on the valve body as the gate travels between a raised open and a lowered closed position. The discs are separated by an annular spacer ring of substantially smaller diameter than the seating surfaces surrounding an interlocking segmented hub formed on the inner juxtaposed surfaces of the discs, the arrangement being such that the spacer ring can be sized to establish an overall gate width which will ensure that the seating surfaces are making proper sealing engagement with the valve seats with the diametral differences increasing the disc flexibility. The spacer ring can be replaced by an appropriately sized spacer ring to compensate for thickness reduction in resurfacing the seating surfaces.

Abstract: A portable field machine for cutting, grinding and lapping the valve seat of a valve body having a valve disc axially translatable in a cylindrical valve chamber with respect to the seat includes a pair of axially spaced spiders having radially extendable arms engageable with the walls of the cylindrical valve chamber on opposed sides of the valve seat, the spiders being interconnected by a rigid shaft which is thereby coaxially positioned with the chamber axis and a tool holder adapted to selectively hold either cutting, grinding or lapping tools is rotatably and reciprocably supported on the shaft for axial movement therealong and rotation thereabout with respect to the valve seat, the tool holder rotatably supporting a carrier which is fixed against relative rotation and which is connected to a drive means for operatively rotating the tool means and tool holder concentrically with respect to the axis and the valve seat to perform profile forming operations thereon, the tool holder including feed means for

Abstract: A portable field machine for cutting, grinding and lapping the valve seat of a valve body having a valve disc axially translatable in a cylindrical valve chamber with respect to the seat includes a pair of axially spaced spiders having radially extendable arms engageable with the walls of the cylindrical valve chamber on opposed sides of the valve seat, the spiders being interconnected by a rigid shaft which is thereby axially positioned with the chamber axis and a tool holder adapted to selectively hold either cutting, grinding or lapping tools is rotatably and reciprocably supported on the shaft for axial movement therealong and rotation thereabout with respect to the valve seat, the tool holder rotatably supporting a carrier which is fixed against relative rotation and which is connected to a drive means for operatively rotating the tool means and tool holder concentrically with respect to the axis and the valve seat to perform profile forming operations thereon, the tool holder including feed means for ra