Encapsulated O-rings, seals details
| Encapsulated O-Rings | Material | Temperature | Check stock |
 | FPM + FEP | -20 to +205 ºC | |
| EPDM Peroxide + FEP | -30 to +130 ºC | |
 | VMQ + FEP | -60 to +180 ºC | |
 | VMQ + FEP | -60 to +180 ºC |
Encapsulated O-rings, ideal in hostile environments
Encapsulated O-Rings consist of a seamless and uniform PTFE encapsulation which entirely encloses a VMQ-made or FPM-made core. They combine the resilience and sealing force of an elastomer with the chemical resistance of PTFE. This produces an elastomeric PTFE ring with high sealing capability.
Unlike traditional O-rings, encapsulated O-Rings are resistant to solvents and are chemically inert (except for attack by alkaline metals, fluorine and some halogenated compounds at high temperatures). In addition, they have a great resiliency substantially equal to those of elastomers and FEP has a very low friction coefficient. Last but not least, their gas permeability is very low.
This is why we highly recommend their use in chemically hostile environments.
Fitting of Encapsulated O-Ring
To minimize the potential damage to encapsulated OR during its fitting, it is essential to get it done it with total care since approximately 90% of the detected trouble are due to improper installation or housing design mistakes.
Installation on a rod
To insert an encapsulated OR to an internal groove can be quite complicated as it is about the seal to collapse into a smaller diameter than the gland it is being fitted into. Therefore, in order not to damage the seal during its installation, we highly recommend pre-heating it in hot water (60 °C – 70 °C) for ten minutes.
It is important to replace the shaft immediately while the seal is still warm and flexible.
Installation on a piston
The correct fitting of an encapsulated OR to a solid piston head groove can be eased by using a fitting cone. In this case as well, our advice is to pre-heat the seal by immersion in hot water in order to gain elasticity.
Anyhow, in both cases, the seals can be damaged or broken. Unlike standard rubber O-Rings, encapsulated O-Rings cannot be stretched which makes their installation more difficult. And a bad installation may have serious failure consequences.
Encapsulated O-Rings, table of tolerances
Encapsulated O-Rings are usually fitted in the same housings than standard O-Rings so that tolerances are strictly the same. We recommend to use the table here below to build housings according to BS 1806 Imperial Standard
| Section | Width (mm) | Height (mm) | ||||||
| Static | Dynamic | Pneumatic | ||||||
| 1,78 | 2,362 | 2,489 | 1,422 | 1,524 | 1,549 | 1,600 | 1,626 | 1,651 |
| 2,62 | 3,556 | 3,683 | 2,083 | 2,210 | 2,286 | 2,362 | 2,388 | 2,438 |
| 3,53 | 4,750 | 4,877 | 2,794 | 2,997 | 3,099 | 3,175 | 3,226 | 3,277 |
| 5,33 | 7,137 | 7,264 | 4,267 | 4,521 | 4,674 | 4,801 | 4,902 | 4,953 |
| 6,99 | 9,525 | 9,652 | 5,588 | 5,893 | 6,147 | 6,274 | 6,426 | 6,477 |
Encapsulated O-Ring, capsules thickness
| Section (mm) | Thickness FEP capsule (mm) | Section (mm) | Thickness FEP capsule (mm) |
| 1,78 | 0,203 | 5,70 | 0,508 |
| 2,00 | 0,203 | 6,99 | 0,508 |
| 2,40 | 0,254 | 8,00 | 0,508 |
| 2,62 | 0,254 | 8,40 | 0,508 |
| 3,00 | 0,254 | 9,50 | 0,508 |
| 3,53 | 0,305 | 10,00 | 0,508 |
| 4,00 | 0,305 | 12,00 | 0,762 |
| 5,00 | 0,381 | 18,00 | 0,762 |
| 5,33 | 0,508 | 20,00 | 0,762 |