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 primary market for encapsulated seals.
    – Versatile encapsulated seals are now a standard choice for filter cartridge element neck seals.
  • Pumps
    – PTFE-made pumps utilise encapsulated seals for corrosive material handling.
    – Plastic pumps, requiring low-load seals, benefit from hollow-core encapsulated seals.
  • Mechanical Seals
    – While Perfluoroelastomers are common, encapsulated seals serve as a cost-effective alternative in various applications.
  • Valves
    – Widely used in air-operated vent valves, steam valves, and water valves for FDA/WRC compliance.
  • Mixers and Vessels
    – Encapsulated seals on lid seals eliminate the need for expensive molds.
    – USP Approval and FDA compliance make them ideal for the pharmaceutical market.
  • Heat Exchangers
    – Tube and shell heat exchangers benefit from Teflon®-jacketed encapsulated seals.
    – Popular in food, drink, and pharmaceutical industries due to USP Approval and FDA Compliance.
  • Flanges
    – Encapsulated seals are vital for sealing flanges and apertures.
    – For optimal chemical resistance with low compression force support, it is advisable to use hollow-core seals in chemical industry applications.

Encapsulated O RingNES Ncap Encapsulated O Ring

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