FEP/PFA Encapsulated O-Rings
Combine the energizing properties of elastomers with PTFE’s superior resistance to extreme temperatures and hostile chemicals with FEP Encapsulated O-Rings and Encapsulated Springs from Advanced EMC Technologies.
What is an Encapsulated O-Ring?
In short, encapsulated O-rings combine the chemical resistance and extreme-temperature performance of FEP or PFA with the elasticity and resilience of silicone, FKM, or stainless steel energizers. Stainless steel springs or rugged elastomers are encapsulated within a durable, chemically resistant jacket made from FEP (fluorinated ethylene propylene) or PFA (perfluoro alkoxy copolymer). These O-rings are used with valve stems, flanges, joints, swivels, pumps, turbo expanders, and waterless fracking.
Materials Used With Encapsulated O-Rings
For the outside of the O-ring, the most popular materials currently in use are FEP, PFA, and PTFE. FEP is highly resistant to chemical attack, offers a low compression set, and has a low coefficient of friction. Its operating temperature range is -420°F through 400°F and is less expensive than PFA. In addition, FEP is available in FDA-approved grades.
PFA is resistant to a wide range of corrosive chemicals, including naphtha, acid, aromatic solvents, petroleum, and alcohol. It has a wider operating temperature range than FEP, from -420°F through 500°F. It also possesses a low compression set and resistance to cracking and stress in addition to a higher overall mechanical strength when compared to FEP. It is also available in grades that have the following approvals: USP IV, FDA-compliant, EU Reg. 1935/2004, ADI-free, and 3-A Sanitary Standards.
The materials used for the interior energizer of encapsulated o-rings include 302 stainless steel for spring energized as well as silicone, FKM (trade name Viton), or EPDM. Whether its a spring-energized approach or a core of silicone, FKM, or EPDM, the interior of the encapsulated o-ring provides the additional resiliency that makes these o-rings so effective for cryogenic applications. Note that silicone and FKM ensure an even pretensioning at the sealing point.
Silicone provides a softer core than FKM and offers very good cold flexibility. Using FKM as the core material means that the O-ring will be able assume its original shape very quickly after installation/deformation due to its outstanding compression set characteristics. It is not, however, as temperature resistant as silicone. While EPDM can be used as a core material, it is not recommended because of how it reacts to the heat involved in manufacturing the encapsulated O-rings.
- Outstanding Chemical Resistance
- Wide Temperature Range
- High Pressure Capability
- Non-Stick and Low Friction
- High Compression Set
- Economical alternative to Fluoroelastomer Rings
- Pumps and Valves
- Heat Exchangers
- Gas Compressors
- And more!
FEP/PFA Encapsulated Springs
Extreme low temperatures make most O-Rings brittle, which can, in turn, lead to seal failure. Advanced EMC Technologies’ Fluorolon ES (Encapsulated Spring) Seal was created specifically to withstand the harsh environments associated with liquid oxygen and the problems associated in sealing other cold media, such as liquid nitrogen and hydrogen.
The Fluorolon ES Seal comprises of 302 stainless flat wound ribbon spring encapsulated in either a FEP or PFA jacket to form an O-Ring.
-75F to 500F (-60C to +260C)
Short durations to +575F (+300C)
-420F to +428F (-250C to +204C)
-75F to 400F (-60C to +205C)
Short durations to +500F (+260C)
-420F to +500F (-250C to +260C)