Gate valve with pressure actuated plug seat

Claim 2

In a valve: a body having an inlet passage, an outlet passage, and a substantially cylindrical bore extending across said passages; opposed individual separate segment seal plates removably disposed in said bore and having external cylindrical surfaces conforming to and engaging the cylindrical wall of said bore, said plates having confronting flat inner upstream and downstream surfaces spaced from and parallel to one another, said plates having inlet and outlet passages, respectively; means for retaining said plates in their respective positions in said bore; a gate structure including a gate between said seal plates and having opposed flat surfaces slidable along said confronting flat inner surfaces, said gate having a flow passage communicable with said plate passages when said structure is in a first position between said plates, said gate further having a cylindrical gate bore paralleling said flow passage; a generally cylindrical one piece plug seat slidably mounted in said gate bore and having opposed flat parallel upstream and downstream surfaces, said plug seat being subject to fluid pressure in said inlet passages acting upon said upstream seat surface to force said downstream seat surface into sealing engagement against said downstream plate surface when said surface occupies a second position between said plates with said plug seat extending across said plate inlet and outlet passages to prevent fluid flow therebetween; and means for shifting said gate structure between said first and second positions.

Claim 3

In a valve as defined in claim 1; said gate having cylindrical surfaces conforming to and slidable along the cylindrical wall of said body bore between said segment seal plates.

Claim 4

In a valve as defined in claim 1; and seal means on said plug seat surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface against said downstream flat surface when said structure occupies said second position.

Claim 5

In a valve as defined in claim 1; said gate having cylindrical surfaces conforming to and slidable along the cylindrical wall of said body bore between said segment seal plates; and seal means on said plug seat surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface against said downstream flat surface when said structure occupies said second position.

Claim 6

In a valve as defined in claim 1; and a seal ring on said plug seat sealingly engaging the wall of said cylindrical gate bore and surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface against said downstream flat surface when said structure occupies said second position.

Claim 7

In a valve: a body having an inlet passage, an outlet passage, and a substantially cylindrical bore extending across said passages; opposed individual segment seal plates removably disposed in said bore and having external cylindrical surfaces conforming to and engaging the cylindrical wall of said bore, said plates having confronting flat inner upstream and downstream surfaces spaced from and parallel to one another, said plates having inlet and outlet passages communicating with said body inlet and outlet passages, respectively; a gate structure including a gate between said seal plates and having opposed flat surfaces slidable along said confronting flat inner surfaces, said gate having a flow passage communicable with said Plate passages when said structure is in a first position between said plates, said gate further having a cylindrical gate bore paralleling said flow passage; a generally cylindrical plug seat slidably mounted in said gate bore and having opposed flat parallel upstream and downstream surfaces, said plug seat being subject to fluid pressure in said inlet passages acting upon said upstream seat surface to force said downstream seat surface into sealing engagement against said downstream plate surface when said structure occupies a second position between said plates with said plug seat extending across said plate inlet and outlet passages to prevent fluid flow therebetween; and means for shifting said gate structure between said first and second positions; and seal means on said plug seat surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface against said downstream flat surface when said structure occupies said second position; and a seal ring on said plug seat adjacent said upstream seat surface and engageable with the wall of said cylindrical gate bore to prevent leakage of fluid from said inlet passages around said plug seat.

Claim 8

In a valve: a body having an inlet passage, an outlet passage, and a substantially cylindrical bore extending across said passages; opposed individual segment seal plates removably disposed in said bore and having external cylindrical surfaces conforming to and engaging the cylindrical wall of said bore, said plates having confronting flat inner upstream and downstream surfaces spaced from and parallel to one another, said plates having inlet and outlet passages communicating with said body inlet and outlet passages, respectively; a gate structure including a gate between said seal plates and having opposed flat surfaces slidable along said confronting flat inner surfaces, said gate having a flow passage communicable with said Plate passages when said structure is in a first position between said plates, said gate further having a cylindrical gate bore paralleling said flow passage; a generally cylindrical plug seat slidably mounted in said gate bore and having opposed flat parallel upstream and downstream surfaces, said plug seat being subject to fluid pressure in said inlet passages acting upon said upstream seat surface to force said downstream seat surface into sealing engagement against said downstream plate surface when said structure occupies a second position between said plates with said plug seat extending across said plate inlet and outlet passages to prevent fluid flow therebetween; and means for shifting said gate structure between said first and second positions; and seal means on said plug seat surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface against said downstream flat surface when said structure occupies said second position; and a seal ring on said plug seat adjacent said upstream seat surface and engageable with the wall of said cylindrical gate bore to prevent leakage of fluid from said inlet passages around said plug seat.

Claim 9

In a valve as defined in claim 1; and a seal ring on said plug seat sealingly engaging the wall of said cylindrical gate bore and surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface against said downstream flat surface when said structure occupies said second position; said gate having cylindrical surfaces conforming to and slidable along the cylindrical wall of said body bore between said segment seal plates.

Claim 10

In a valve as defined in claim 1; and seal means on the exteriors of said seal plates surrounding said inlet passages and outlet passages and sealingly engaging the cylindrical wall of said body bore.

Claim 11

In a valve as defined in claim 1; said gate having cylindrical surfaces conforming to and slidable along the cylindrical wall of said body bore between said segment seal plates; and seal means on the exteriors of said seal plates surrounding said inlet passages and outlet passages and sealingly engaging the cylindrical wall of said body bore.

Claim 12

In a valve: a body having an inlet passage, an outlet passage, and a substantially cylindrical bore extending across said passages; opposed individual segment seal plates removably disposed in said bore and having external cylindrical surfaces conforming to and engaging the cylindrical wall of said bore, said plates having confronting flat inner upstream and downstream surfaces spaced from and parallel to one another, said plates having inlet and outlet passages communicating with said body inlet and outlet passages, respectively; a gate structure including a gate between said seal plates and having opposed flat surfaces slidable along said confronting flat inner surfaces, said gate having a flow passage communicable with said plate passages when said structure is in a first position between said plates, said gate further having a cylindrical gate bore paralleling said flow passage; a generally cylindrical plug seat slidably mounted in said gate bore and having opposed flat parallel upstream and downstream surfaces, said plug seat being subject to fluid pressure in said inlet passages acting upon said upstream seat surface to force said downstream seat surface into sealing engagement against said downstream plate surface when said structure occupies a second position between said plates with said plug seat extending across said plate inlet and outlet passages to prevent fluid flow therebetween; and means for shifting said gate structure between said first and second positions; and a seal ring on said plug seat sealingly engaging the wall of said cylindrical gate bore and surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface aGainst said downstream flat surface when said structure occupies said second position; and a seal ring on said plug seat adjacent said upstream seat surface and engageable with the wall of said cylindrical gate bore to prevent leakage of fluid from said inlet passages around said plug seat.

Claim 13

In a valve: a body having an inlet passage, an outlet passage, and a substantially cylindrical bore extending across said passages; opposed individual segment seal plates removably disposed in said bore and having external cylindrical surfaces conforming to and engaging the cylindrical wall of said bore, said plates having confronting flat inner upstream and downstream surfaces spaced from and parallel to one another, said plates having inlet and outlet passages communicating with said body inlet and outlet passages, respectively; a gate structure including a gate between said seal plates and having opposed flat surfaces slidable along said confronting flat inner surfaces, said gate having a flow passage communicable with said plate passages when said structure is in a first position between said plates, said gate further having a cylindrical gate bore paralleling said flow passage; a generally cylindrical plug seat slidably mounted in said gate bore and having opposed flat parallel upstream and downstream surfaces, said plug seat being subject to fluid pressure in said inlet passages acting upon said upstream seat surface to force said downstream seat surface into sealing engagement against said downstream plate surface when said structure occupies a second position between said plates with said plug seat extending across said plate inlet and outlet passages to prevent fluid flow therebetween; and means for shifting said gate structure between said first and second positions; and a seal ring on said plug seat sealingly engaging the wall of said cylindrical gate bore and surrounding said plate outlet and engageable with said downstream flat surface to supplement the sealing engagement of said plug seat surface aGainst said downstream flat surface when said structure occupies said second position; and a seal ring on said plug seat adjacent said upstream seat surface and engageable with the wall of said cylindrical gate bore to prevent leakage of fluid from said inlet passages around said plug seat.

Claim 14

In a valve as defined in claim 10; said gate having cylindrical surfaces conforming to and slidable along the cylindrical wall of said body bore between said segment seal plates.

Claim 15

In a valve as defined in claim 10; and seal means on the exteriors of said seal plates surrounding said inlet passages and outlet passages and sealingly engaging the cylindrical wall of said body bore.