Encapsulated O Ring Advantages

Encapsulated O Ring Advantages & Disadvantages

Encapsulated O Ring Advantages. The following article outlines some of the benefits of using Encapsulated O Rings.

What is an Encapsulated O Ring?

An Encapsulated O Ring consists of an elastomer stimulating core (Fluorocarbon – Viton® / FPM / Silicone), which has a seamless shield made from FEP (Fluorinated Ethylene Propylene) or PFA (Perfluoroalkoxy – copolymer), which are chemically resistant and used to prevent the corrosive fluids or gasses from getting through to the elastomer in an application.

They are not in fact elastomers, they are plastic and combine the best characteristics of plastics and elastomers for the best sealing properties of rubber. Whilst the outer FEP or PFA shield is resistive and hard, the core elastomer supplies the memory of the O Rings when they are put under a compressive force. The combination of a chemically resistant polymer shield over a low compression set elastomer ensures unique properties.

FEP and PFA Encapsulated O Rings combine the outstanding chemical and thermal resistance. The exceptionally low ratio of friction makes them a perfect choice when you are concerned about surface wear. FEP and PFA show an extended service life and its resistance to chemicals persists supreme throughout the extensive scope of temperatures (between -60°C and +260°C), this provides an exceptional seal popular for high friction and aggressive chemical application. They are a top choice when the rubber-elastic quality of the seal is substantial, but the application also demands better chemical resistance than regular elastomers (as the aggressive chemicals and extreme temperatures can destroy standard O Rings). FEP and PFA Encapsulated O Rings can be used wherever an elastomer’s chemical resistance is inadequate.

Encapsulated O Ring Profiles and Dimensions

The most used profile is the circular cross-section. Oval, rectangular and square profiles can be manufactured on demand. Since there are extra tooling expenses for complex encapsulations, deviations including small amounts are not generally economical. Encapsulated O Rings can, in fact, be proposed in all the metric and imperial cross-section thicknesses. Client-specific products can also be executed without trouble. Standard cross-section thicknesses in many dimensions can be provided from the stock. This guarantees the cost-effectiveness and rapid availability of what the client requires.

The minimum manufacturing size of the inner diameter depends on the cross-section thickness of the O Ring. There are no restrictions on the maximum size of the inner diameter. Since encapsulated O Rings are just slightly extendable and compressible, the fitting space must be situated to these attributes when diameters are small.

Encapsulated O Ring Advantages:

Low contamination
Low penetrability
Low ratio of friction (between 0.1 and 0.2)
FDA and EC1935/2004 & EC2023/2006 compliant
Applications in a wide scope of temperatures
Excellent resistance to nearly all media
Greatly suited for use in the Food, Pharmaceutical, and Chemical Processing industries
Cost-effective, high-performance seal for many critical application areas
High impact strength

When Encapsulated O Rings should not be used:

Under high pressure
In dynamic applications
In contact with abrasive media
Where the housing design demands excessive stretch

Characteristics of FEP and PFA

FEP and PFA are very much alike in their features. PFA stands out for its exceptional thermal resistance at temperatures of over 200°C. The best possible encapsulated O Ring can be chosen for a specific application in consequence to the abilities for combining two encasing materials and two core materials. The structure of the inner elastomer as a hollow core widens the scope of applications to uses that demand rather low contact forces.

Benefits of FEP encapsulation:

Thermal stability (between -55°C and +200°C), solution for high temperature sealing application
Prominent chemical and corrosion resistance
Low ratio of friction (between 0.1 and 0.2)
Low compression set
FDA and EC1935/2004 & EC2023/2006 compliant
Exceptionally low absorption of acids and solvents, as well as alkaline solutions
Pressure resistance between 70 and 200 bar with support ring
High impact strength
Smooth surface
Non-flammable

Benefits of PFA encapsulation:

All the benefits of FEP encapsulation
Longer service life, better flex life
Outstanding crack and stress resistance
Greater mechanical endurance
Greater temperature resistance

For more information on profiles, compliant approvals and temperature ranges view our full range of Encapsulated O Rings here

E & OE. M Barnwell Services endeavours to make sure all the content is correct. Information has been gained from manufacturing partners.