Plug valve having composite seat element

Claim 2

In a plug valve of the type wherein a ported plug is rotatably mounted in a valve body for movement between a valve closed position wherein it blocks a fluid passage through the valve and a valve open position wherein the plug port becomes a continuation of the body passage, seat rings mounted in said body surrounding passage openings at opposite sides of the plug and having spherical surface means adapted for engaging corresponding spherical surface means on said plug during rotation of the plug between said positions, at least one of said seat rings being a composite seat ring comprising a metal annulus having an axis parallel with the fluid passage and formed with said spherical surface means and an annular groove extending in a direction normal to the axis of said consisting essentially of a flat sided relatively narrow annulus of synthetic plastic material, said annulus having a substantially greater width than thickness and laying in width in a plane normal to the axis of the annulus, said annulus having its outer periphery fixed in said annular groove and its innere periphery projecting from said metal seat ring into deformable pressure engagement with said surface means of the plug.

Claim 3

In the plug valve defined in claim 1, both of said seat rings being of substantially the same composite seat ring structure.

Claim 4

In the plug valve defined in claim 1, means providing an annular internal recess at the inner end of the side of said groove between said initial seal ring and said spherical surface means on said one seat ring to provide space wherein the innEr periphery of the initial seal ring may deflect when pressed with sufficient force against the plug surface.

Claim 5

In the plug valve defined in claim 1, means within said valve body providing upper and lower trunnions mounting said plug for rotation about an axis normal to the axis of its port, said upper trunnion comprising a hollow tubular member fixed on the body and having a cylindrical inner end section projecting into a cylindrical recess in said plug, and a valve actuating stem rotatably mounted in said hollow trunnion extending through said hollow trunnion into an axially detachable torque transmitting association with said plug whereby said plug recess provides a rotative bearing fit with the inner end section of said upper trunnion during rotation of said plug by said stem.

Claim 6

In the plug valve defined in claim 1, means in the slidable mounting of said one seat ring providing an annular resilient seal member radially compressed between oppositely disposed axially extending cylindrical surfaces provided respectively to said body and metal annulus, and a metal extrusion prevention ring having an inclined face surrounding said cylindrical surface provided to said metal annulus within said slidable mounting and disposed axially between said seal member and a corresponding inclined annular surface on said metal annulus with said inclined face of said metal extrusion prevention ring bearing against said inclined annular surface on said metal annulus.

Claim 7

In a plug valve of the type wherein a ported plug is rotatably mounted in a valve body for movement between a valve closed position wherein it blocks a fluid passage through the valve and a valve open position wherein the plug port becomes a continuation of the body passage, seat rings mounted in said body surrounding passage openings at opposite sides of the plug and having spherical surface means adapted for engaging corresponding spherical surface means on said plug during rotation of the plug between said positions, at least one of said seat rings comprising a metal annulus formed with said spherical surface means and mounted in a body recess for displacement toward and from the plug, resilient means biasing said one seat ring toward said plug, oppositely disposed axially extending cylindrical surfaces provided respectively to said body recess and said one seat ring and defining an annular space therebetween, the inner end of one of said cylindrical surfaces intersecting with a surface inclined toward the other said cylindrical surface, an annular resilient seal member compressed between said oppositely disposed cylindrical surfaces and an elastically deformable metal wedge ring surrounding said cylindrical surface provided to said one seat ring, said wedge ring being disposed axially between said resilient seal member and said inclined surface and having on one side an axial face adapted to be engaged by said resilient seal member and on the other side an inclined face adapted to engage said inclined surface whereby said one seat ring is mounted for movement relative to said body recess and said plug and said elastically deformable metal wedge ring sealingly closes any variations in spacing which may occur between said one seat ring and said body recess.

Claim 8

In a plug valve of the type wherein a ported plug is rotatably mounted in a valve body for movement between a valve closed position wherein it blocks a fluid passage through the valve and a valve open position wherein the plug port becomes a continuation of the body passage, seat rings mounted in said body surrounding passage openings at opposite sides of the plug and having spherical surface means adapted for engaging corresponding spherical surface means on said plug during rotation of the plug between said positions, at least one of said seat rings comprising a metal annulus formed with said spherical surface means and mounted in a body recess for displacement toward and from the plug, resilient means biasing said one seat ring toward said plug, oppositely disposed axially extending cylindrical surfaces provided respectively to said body recess and said one seat ring and defining an annular space therebetween, the inner end of one of said cylindrical surfaces intersecting with a surface inclined toward the other said cylindrical surface, an annular resilient seal member compressed between said oppositely disposed cylindrical surfaces and an elastically deformable metal wedge ring surrounding said cylindrical surface provided to said one seat ring, said wedge ring being disposed axially between said resilient seal member and said inclined surface and having on one side an axial face adapted to be engaged by said resilient seal member and on the other side an inclined face adapted to engage said inclined surface whereby said one seat ring is mounted for movement relative to said body recess and said plug and said elastically deformable metal wedge ring sealingly closes any variations in spacing which may occur between said one seat ring and said body recess.

Claim 9

In the plug valve defined in claim 6, said wedge ring being an internal steel ring of uniform cross section.

Claim 10

In the plug valve defined in claim 6, both of said seat rings being of substantially the same structure and slidably mounted on the body in the same way.

Claim 11

The plug valve defined in claim 6 wherein said body recess is provided by at least two stepped cylindrical bores, the larger diameter cylindrical bore provides said cylindrical surface to said body recess, said inclined surface is provided between two axially extending cylindrical surfaces provided to said one seat ring and said axially extending cylindrical seat ring surfaces are radially spaced from said stepped cylindrical bore surfaces.

Claim 12

In a plug valve comprising a Body having opposed passage sections opening internally into a plug mounting space, a ported plug rotatably mounted in said space for movement between a valve closed position wherein it blocks a fluid passage, through the valve and a valve open position wherein the plug port becomes a continuation of the body passage sections, seat rings in said body surrounding passage section openings at opposite sides of the plug and having spherical surface means adapted for engaging corresponding spherical surface means on said plug during rotation of the plug between said positions, means mounting said seat rings for displacement toward and from the plug, resilient means biasing said seat rings toward said plug, upper and lower trunnion means within said body mounting said plug for rotation about an axis that is substantially normal to the seat ring axis, said lower trunnion means being fixed on the body and having a cylindrical inner end section projecting within a cylindrical recess in said plug, said upper trunnion means comprising a hollow tubular member fixed on the body and having a cylindrical inner end section projecting into said space into rotative bearing fit with a cylindrical recess in said plug, a valve actuating stem rotatably mounted in said hollow trunnion and having an outer end adapted to be connected to an actuator device, means on the inner end of said stem and within said plug recess providing an axially separable torque transmitting coupling between the stem and plug, thrust bearing means intereposed between the lower end of said stem and the lower end of said hollow trunnion comprising a flat sided bearing annulus disposed between opposed flat radial surfaces on the stem and hollow trunnion, and coaxial bushings in said plug recesses providing radial bearings between the plug and said trunnions.

Claim 13

In a plug valve comprising a Body having opposed passage sections opening internally into a plug mounting space, a ported plug rotatably mounted in said space for movement between a valve closed position wherein it blocks a fluid passage, through the valve and a valve open position wherein the plug port becomes a continuation of the body passage sections, seat rings in said body surrounding passage section openings at opposite sides of the plug and having spherical surface means adapted for engaging corresponding spherical surface means on said plug during rotation of the plug between said positions, means mounting said seat rings for displacement toward and from the plug, resilient means biasing said seat rings toward said plug, upper and lower trunnion means within said body mounting said plug for rotation about an axis that is substantially normal to the seat ring axis, said lower trunnion means being fixed on the body and having a cylindrical inner end section projecting within a cylindrical recess in said plug, said upper trunnion means comprising a hollow tubular member fixed on the body and having a cylindrical inner end section projecting into said space into rotative bearing fit with a cylindrical recess in said plug, a valve actuating stem rotatably mounted in said hollow trunnion and having an outer end adapted to be connected to an actuator device, means on the inner end of said stem and within said plug recess providing an axially separable torque transmitting coupling between the stem and plug, thrust bearing means intereposed between the lower end of said stem and the lower end of said hollow trunnion comprising a flat sided bearing annulus disposed between opposed flat radial surfaces on the stem and hollow trunnion, and coaxial bushings in said plug recesses providing radial bearings between the plug and said trunnions.

Claim 14

In the plug valve defined in claim 10, said hollow trunnion having an enlarged upwardly open bore in its upper end, and a cylindrical seal element in said bore having external peripheral sealing engagement with said trunnion and rotary sealing engagement with said stem, said seal element being axially retained in said bore by a readily removable fastener whereby said seal element may be replaced or repaired without separating the stem from its operative mounting in the trunnion.