Delivering Fluid Sealing Solutions Since 1972

Encapsulated O Rings

Encapsulated O Rings that are proven to protect the core

M Barnwell Services, the UK’s leading manufacturer, stockist and distributor of Fluid Sealing Products offers a comprehensive range of quality Fluorinated ethylene propylene (Teflon® FEP), PTFE and Perfluoroether (PFA) Encapsulated O Rings.

The design completely encloses a core material and acts as a barrier if any pressure is exerted on the seal. The Encapsulated O Rings is widely used across a range of industries, including Food and Drink (FDA), Chemical Processing, Petrochemical, Pharmaceutical, Paints and Dyes, Refrigeration and Cosmetics. For Cryogenic applications we also supply the industry leading Astra Seal.

encapsulated o rings

Available in a wide range of standard Metric and Imperial sizes the Encapsulated O Rings can be supplied as small as 4.5mm ID and with no maximum size. M Barnwell Services Encapsulated O Rings are compliant with FDA, ADI-Free, 3A Sanitary Standards, EU Reg. 1935/2004 and USP Class VI.

We also supply a range of Viton (FKM) FDA and EC1935/2004 & EC2023/2006 Approved, Silicone (VMQ) and EPDM Core with FEP Jacket Encapsulated O Rings.

Seal Profile Options:

Encapsulated O Ring profiles

Temperature range chart:

encapsulated o ring temperature range chart

Encapsulated Seal Applications

  • Filter Elements
    Filtration is the largest market for encapsulated seals and huge volumes are sold for filter cartridge element neck seals. Where once the filter manufacturer would have needed to determine the end use before selecting a suitable O Ring material, he can now fit encapsulated seals as standard due to the versatile ability.
  • Pumps
    In the chemical process industry pumping corrosive material is very problematic from a sealing point of view. PTFE made pumps have utilised many encapsulated seals at various critical points of construction. Plastic pumps often require low load seals, so hollow core is recommended for this application.
  • Mechanical Seals
    Manufactures use Perfluoroelastomers as a seal of choice however, there are still many applications where encapsulated seals can be used as a low cost alternative
  • Valves
    The valve industry uses encapsulated seals on a wide scale at various locations within a valve. Often found in air operated vent valves, steam valves and water valves (due to FDA / WRC compliance)
  • Mixers and Vessels
    Manufacturers of large diameter mixers and vessels enjoy the benefits of using encapsulated seals on lid seals, this removes the need for expensive moulds for production. The USP Approval and FDA compliance of the encapsulated seals makes them ideal for the pharmaceutical market.
  • Heat Exchangers
    In certain applications, tube and shell heat exchangers benefit from the use of encapsulated seals. The Teflon ® jacket allows easy splitting of plate stacks even after long periods of compression. USP Approval and FDA Compliance makes this solution very popular in the food, drink and pharmaceutical industry.
  • Flanges
    The sealing of flanges and apertures in various industries is another good market for encapsulated seals. Liquid gasses and refrigerants are difficult to seal and permeability is a major consideration. In the chemical industry much of the equipment is manufactured from glass for optimal chemical resistance. Hollow core encapsulated seals are recommended in this application, this supports the low compression force.

The M Barnwell Services’ experts can determine if an FEP / PFA encapsulated O Ring is suitable for your particular application. If you would like more information, download our catalogue or contact a member of the team.

We also have over 50 million O Rings and Back-Up Rings in stock. For more information on our range of O Rings click here.

E & OE.


O-Ring Sizes- 4.5mm ID minimum and with no maximum standard size.


Fluorinated ethylene propylene (Teflon® FEP), Perfluoroether (PFA), and PTFE.

Silicone and FKM are used as the material for the core of the encapsulated O Ring whilst EPDM is not recommended due to heat-related variations during the production process. FKM and silicone withstand these variations during manufacturing without a decrease in execution.
Silicone core – The silicone core is notably tender than an FKM. It’s also more temperature resistant (great flexibility in both high and low temperatures)

FKM core – FKM attributes great rubber manufacturing qualities. Its outstanding compression set allow it to re-assume to its original form after its deformation

FEP encapsulation – FEP (Fluorinated Ethylene Propylene) provides an O Ring with its immense features regarding its resistance to most games, chemicals and liquids (except liquid alkali metals and various fluorine compounds)

PFA encapsulation – PFA (Perfluoroalkoxy Copolymer) is similar to FEP in its application. It is remarkable due to superior cold flow attributes and improved mechanical features at risen temperatures.

Tolerances For ID

Encapsulated O Rings cannot be manufactured with the same tolerances as standard O Rings. They can deform due to the fluctuating inflexibility of the casino and the core because of temperature impacts.


Encapsulated O Rings Metric and Imperial Kits, Splicing Kits & Top-up Bags are available

Bespoke Encapsulated O Ring Kits and selection Boxes are also available

Associated Products

O Rings, Encapsulated O Rings (FEP/PFA), Lube, Gauge / O Ring material tester, Quad Rings® (X-Rings) / Nu-lip Rings, Tube, Anti-extrusion Rings, Splicing Kits, Back-up Rings, O Ring Cord, Anti-extrusion Rings, Lubricants and Adhesives