Teflon Envelope Gaskets


Envelope gaskets utilizing PTFE jacket have become popular for use in severely corrosive services because of their low minimum seating stresses, excellent creep resistance, high deformability and choice of filler materials to assure optimum performance on any specific application.


  • pH 0-14
  • Temperature range of -120°F (-84°C) to 500°F (260°C)

There are two basic designs of envelopes:

  • SLIT TYPE: Sliced from cylinders and split from the outside to within approximately 1/16” of the inside diameter. The bearing surface is determined by the filler dimensions. Clearance is required between the I.D. of the filler and the envelop I.D. The gasket O.D. normally rests within the bolt circle and I.D. is approximately equal to the nominal I.D. of pipe. Available in size range from ½” to 24”.
  • Machined Type: The jacket is machined from the O.D. to within approximately 1/32” of the I.D. The jacket I.D. fits flush with pipe bore and the O.D. nests within the bolts. Available In sizes from ½” to 24”. Machined envelopes are more expensive than SLIT Type since considerably more material is lost in machining.

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