Seal

Apparatus for sealing in high pressure, temperature cycled applications between the walls of an axially movable valve stem and a stuffing box around the valve stem, the stuffing box having a port in its bottom and the valve stem extending through the port and out of the stuffing box, comprising:

• first and second elastic metal ring gaskets disposed in such stuffing box around such valve stem, and
• annular compliant seal means disposed in such stuffing box around such valve stem and sandwiched between said gaskets,
• said seal means including first and second annular portions of tough, compliant material having a low coefficient of friction comprising tetrafluoroethylene polymer with up to about fifteen percent molybdenum disulfide adjacent said first and second gaskets, respectively, and a core portion disposed between said first and second portions and composed of a material comprising compacted graphite having a lower coefficient of thermal expansion than said material of said first and second annular portions, said first and second annular portions comprising make-up rings in sealing engagement with such stem and such stuffing box and said core portion comprising a core ring having an inner diameter larger than the outer diameter of such stem, and further including a bearing ring of tough, compliant material disposed around the inner periphery of said core ring between said core ring and such stem.

Apparatus for sealing in high pressure, temperature cycled applications between the walls of an axially movable valve stem and a stuffing box around the valve stem, the stuffing box having a port in its bottom and the valve stem extending through the port and out of the stuffing box, comprising:

• first and second elastic metal ring gaskets disposed in such stuffing box around such valve stem,
• annular compliant seal means disposed in such stuffing box around such valve stem and sandwiched between said gaskets,
• said seal means including first and second annular portions of tough, compliant material adjacent said first and second gaskets, respectively, and a core portion disposed between said first and second portions and composed of a material having a lower coefficient of thermal expansion than said material of said first and second annular portions,
• and including means for compressing said first and second gaskets such that said gaskets are partially flattened and their inner and outer peripheral edges are coined into metal-to-metal sealing engagement with such stem and such stuffing box, and for urging said first and second annular portions of said seal means into sealing engagement with such stem and such stuffing box.

Apparatus for sealing in high pressure, temperature cycled applications between the walls of an axially movable valve stem and a stuffing box around the valve stem, the stuffing box having a port in its bottom and the valve stem extending through the port and out of the stuffing box, comprising:

• first and second elastic metal ring gaskets disposed in such stuffing box around such valve stem,
• annular compliant seal means disposed in such stuffing box around such valve stem and sandwiched between said gaskets,
• said seal means including first and second annular portions of tough, compliant material adjacent said first and second gaskets, respectively, and a core portion disposed between said first and second portions and composed of a material having a lower coefficient of thermal expansion than said material of said first and second annular portions, and
• means for compressing said first and second gaskets such that said gaskets are partially flattened and their inner and outer peripheral edges are coined into metal-to-metal sealing engagement with such stem and such stuffing box, and for urging said first and second annular portions of said seal means into sealing engagement with such stem and such stuffing box,
• said core portion being annular in configuration with its outer radial periphery adjacent such stuffing box and having an inner diameter greater than the outer diameter of such stem, said seal means including a third annular portion of tough, compliant material disposed between said core portion and such stem.