A FEP/PFA encapsulated O-ring is a static sealing element and consists of an elastomer core ring, that is seamlessly encased in a FEP/PFA jacket. FEP/PFA is a perfluorinated polymer and like PTFE, provides excellent resistance against chemicals. The elastic pressing force is comparable to that of a normal O-ring. However, for the installation it should be considered that there are limits to the expansion and compression.
FEP/PFA encapsulated O-rings come in the same dimensions as elastomer O-rings and have similar installation parameters. It provides a good chemical resistance and due to its physiological harmlessness and sterilizability it is oftenly used in the chemical industry, petrochemistry as well as in the medicine and food industry.
FEP/PFA encapsulated O-rings come in the same dimensions as elastomer O-rings and have similar installation parameters. It provides a good chemical resistance and due to its physiological harmlessness and sterilizability it is oftenly used in the chemical industry, petrochemistry as well as in the medicine and food industry.
FEP/PFA encapsulated O-ring
Fields of application
static
dynamic
single acting
double acting
Linear
Rotating
oszilating
Main use
a simple sealant with an exellent chemical resistance
Materials
elastomers, FEP/PFA
Advantages
- high resistance against aggressive media
- high-performance in critical applications
- wide operating temperature range
- cost-effective
- physiological harmlessness, sterilisability
- for use in the food, chemical and petrochemical industries
- FDA-compliancy
- low coefficient of friction
- low permeation
Field of application
FEP/PFA encapsulated O-rings are used in many various technical areas. Especially where the application range of conventional O-rings has been exhausted.
On account of the good chemical resistance, physiological harmlessness and the fact that they can be sterilised, they are widely used in the chemical and petrochemical, food and medical industries.
The FEP/PFA O-ring should not be used in applications with abrasive contact surfaces or abrasive media, as these can destroy the encapsulation.
Main fields of application:
- axial-static sealing
- radial-static sealing
Technical values
Materials
Pressure
up to 25 MPa
Temperature
-25°C / +200°C (material dependent)
Speed
-
Pressure
up to 25 MPa
Temperature
-60°C / 200°C (material dependent)
Speed
-
Maximum values temperature, speed and pressure are simultaneously not applicable! The values vary in dependence of material and media. For technical queries please contact our application consultants – we have the right solution for you.
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PTFE O-ring
Definition of O-ring dimensions and ordering sizes
- Inside diameter d1 from approx. 6 mm to 5000 mm
- Cross section d2 from approx. 1,5 mm to 20 mm
Sealing effect
The sealing effect of the FEP/PFA encapsulated O-ring results from the axial or radial compression of its cross section during installation, comparable to the elastomer O-ring. The elastomer core ensures an even pre-pressing through its elastic properties. However, due to the FEP/PFA encapsulation, the FEP/PFA O-rings have less elasticity.
Design Information
In general:
For the installation of FEP/PFA encapsulated o-rings, the same groove design applies as to standard elastomer O-rings.
Stretching/compression:
In contrast to elastomer O-rings, FEP/PFA encapsulated O-rings have limited stretch and compression due to their encapsulation.
Groove degree of filling:
The recommended maximum values are lower than for elastomer O-rings and depending on the application:
- static sealing 12 – 22%
Installation precompaction:
General requirements for the installation area:
- square groove
- low pressing forces into the housing
- limited O-ring stretch
When installing FEP/PFA encapsulated O-rings, the same recommendation apply regarding groove design and the corresponding installation dimensions as for elastomer O-rings.
For the installation of FEP/PFA o-rings, split grooves are recommended.
Installation Instructions
Correct assembly is crucial for the sealing function of the FEP/PFA encapsulated O-rings.
- The contact surfaces of the installation area must not be damaged by scratches, dents or similar.
- Edges and insert inclinations must be deburred as per guidlines
- Heat the O-ring in hot, compatible media before assembly
- Install the O-ring immediately after heating, it is easier to deform
- The O-ring must not be buckled or overstretched
Your contact person for
Technology - General sealing topics, special constructions
Ms. Karen Goller
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