Vulcan Chem-Ring® seals combine the resilience and sealing force of an elastomer with the chemical resistance of Teflon®. They consist of an elastomeric core of Silicone or Viton® with a relatively thin, moulded encapsulation of FEP or PFA polymer.


The seamless, uniform FEP/PFA encapsulation provides the Chem-Ring’s near universal sealing capability, whilst the continuous reset, and the constant pressure of the encapsulation onto the sealing point, is performed by the elastomeric core. The result is an overall sealing compression that increases the media pressure. The Chem-Ring behaves like a highly viscous fluid, any pressure exerted on the seal is transmitted practically undiminished in all directions.

  • Pumps and Valves

  • Filters

  • Reactor Vessels

  • Pressure Vessels

  • Mechanical Seals

  • Heat Exchangers

  • Autoclaves

  • Cryogenics

  • Hose Coupling Seals

  • Pipelines

This combination of the best qualities of the FEP / PFA encapsulation with the Silicone or Viton® rubber core creates an inexpensive, high performance solution to many critical sealing problems.
Utilize Vulcan FEP/PFA Encapsulated ‘O’-Rings to replace standard material ‘O’-Rings when they suffer :

  • Chemical Attack

  • ‘O’-Ring swell

  • ‘O’-Ring compression set

  • Gas permeation-or where sterility is needed (Food, Pharmaceutical, Chemical manufacturing Industries).

  • Where standard materials cause problems related to surface friction (Eg. Reciprocating Movement).or where standard materials cause problems related to surface friction (Eg. Reciprocating Movement).

  • Provide an alternative to Kalrez® and similar Perfluoroelastomers - where Kalrez® may be not necessary ie. Vastly reducing the seal’s cost

  • Replace solid P.T.F.E rings - these hard, unforgiving seals suffer from cold flow and creep and should not be used, given the superior capabilities and performance of FEP/PFA Encapsulated ‘O’-Rings.

  • Replace envelope gaskets in vessel lid seals to provide full seal integrity - avoiding possible product contamination or seal failure.