Abstract: A valve comprises a valve stem 2 surrounded in part by a packing material 3, and compression means arranged to bring the packing material into sealing engagement with the valve stem. The compression means includes a spring assembly comprising resilient springs 21 enclosed within a housing member 22 having a closure member 23 slidably mounted within it. The housing member 22 and the closure member 23 are provided with engagement means 27,28 acting to retain the closure member 23 captive within the housing member 22.

Abstract: A gasket including an annular metal core and at least one radially outwardly projecting, compressible gasket ring made of a high-temperature resistant, expanded graphite material. The gasket ring is arranged on the metal core and, after mounting, is essentially aligned with the metal core. The metal core has a circular recess in a form of a V-shaped trough on an outer circumference thereof, into which recess the gasket ring is inserted. The gasket ring is made of a graphite material and has on at least two axially facing side edges adjacent the metal core an inclined slope of approximately 45.degree.. The metal core consists of a high strength metal alloy selected from the group consisting of 304L stainless steel, 316L stainless steel, 321 stainless steel, 329 stainless steel and inconel 600.