Encapsulated O-Rings
FEP and PFA encapsulated O-rings consist of an elastomeric core and a seamlessly closed casing of modified PTFE. The elastomer core of encapsulated O-rings is typically made of FKM (Viton) or VMQ (silicone) and guarantees a uniform pre-tensioning at the sealing point. The seamless encapsulated O-ring casing is composed of FEP (fluorinated ethylene propylene) or PFA (perfluoroalkoxy-copolymer). The encapsulated O-ring casing ensures reliable sealing and high resistance to aggressive media. This produces performance similar to that of a PTFE material.
Encapsulated O-rings are exclusively used in static applications since movement or abrasive media can destroy the casing.
Features of Encapsulated O-Rings
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Encapsulated O-rings have very good resistance to nearly all media ( exceptions are alkali metals and some fluorine compounds)
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Encapsulated O-rings are used in applications in broad range of temperatures
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Encapsulated O-rings are superbly suited for use in the food, chemical and pharmaceutical industries
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Encapsulated O-rings have low contamination
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Encapsulated O-rings have low permeation
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Encapsulated O-rings have a low coefficient of friction that prevents the stick-slip effect
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Encapsulated O-rings are cost-effective, high-performance seals for many critical application areas
Limitations of Encapsulated O-Rings
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Encapsulated O-rings are not compatible with ozone, direct sunlight, UV, or weathering
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Encapsulated O-rings have poor resistance to aromatic fuels, glycol-based brake fluids, polar solvents, non-flammable hydraulic fluids (HFD), aromatic/chlorinated hydrocarbons, and strong acids
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Encapsulated O-rings have a 15 year shelf life
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Service temperature range (varies with application) Typically -20°F to 200°F (-30°C to 100°C) *Special formulations allow range of -65°F to 275°F (-54°C to 135°C)
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Encapsulated O-rings are not recommended for dynamic applications
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Encapsulated O-rings are not recommended for contact with abrasive media
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Encapsulated O-rings are not recommended for high pressure applications
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Encapsulated O-rings are not recommended for high stretch applications or over compression
Please consult a TKF Tech Engineer about your specific application and we will use our decades of experience to formulate a solution that fits your need.
FEP vs PFA Encapsulation
In the context of encapsulated O-rings, FEP and PFA are very similar in their characteristics. PFA stands out for its greater thermal resistance at temperatures exceeding 200 °C. Thanks to the opportunities for combining two encasing materials and two core materials for encapsulated O-rings, the best possible encapsulated O-rings can be selected for a particular application. The formation of the inner elastomer as a hollow core expands the range of applications to uses that require relatively low contact forces.
Advantages FEP
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FEP encapsulated O-rings have high resistance to numerous chemicals
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FEP encapsulated O-rings have high corrosion resistance
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FEP encapsulated O-rings have low compression set
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FEP encapsulated O-rings have a low coefficient of friction
Advantages of PFA
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PFA encapsulated O-rings have all the benefits of FEP encapsulation
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PFA encapsulated O-rings have greater high temperature resistance
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PFA encapsulated O-rings have greater mechanical strength
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PFA encapsulated O-rings have a longer service life
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PFA encapsulated O-rings have a greater resistance to cracking
Please consult a TKF Tech Engineer about your specific application and we will use our decades of experience to formulate a solution that fits your need.
TKF Tech is a proud partner of Canyon Components, LLC and can provide Canyon Components materials, O-rings, and custom parts. Click here to see what Canyon has to offer.
