The encapsulated O-rings, the seals with an encapsulation that sets it apart
We have decided to give the encapsulated O-rings the importance they have always deserved, creating a specific area with its technical data sheet, 3D photos of the part both whole and in section, and a video of it in movement.
The encapsulated O-ring consist of a core in silicon (VMQ) or fluorocarbon (FPM) which is completely enclosed in a seamless FEP or PFA encapsulation. These seals are the ideal solution in the face of sealing problems given their chemical resistance, elastic properties, and low friction.
The encapsulated seals combine the resilience and sealing typical of elastomers with the chemical resistance of PTFE. Because they are made of a core of VMQ or FPM covered with a thin capsule of the polymers FEP or PFA, the result is a high-performance sealing product.
Because they are resistant to solvents and are chemically inert (except for contact with alkaline metals, fluorine, and some halogen compounds at high temperature), the encapsulated O-rings compensate for some of the limitations of traditional O-ring seals. On the one hand, they provide a level of resilience very similar to that of elastomers. And on the other hand, the extremely low coefficient of friction (0.1 and 0.2) of the polymer FEP allows for a very low permeability to gases. This means that encapsulated O-ring seals are almost universally used in harsh environments.
Due to all of these features, encapsulated O-ring are used above all in applications such as pumps and valves, marine motors, mechanical locking, filters, pneumatic motors, heat exchangers, autoclaves, pipelines, and compressors, among others.
The materials used for the covering of the seal are FEP and PFA, as we mentioned earlier. Their properties are similar although PFA displays better behaviour with temperatures in excess of 200 ºC. For any inquiries, do not hesitate to consult the technical data sheet:
| O-Ring | Profile | Material | Temperature |
| Encapsulated |  |
FPM + FEP | -20 to +205 ºC |
| Encapsulated |  |
VMQ + FEP | -60 to +180 ºC |
The seamless uniform FEP encapsulation provides the seals almost a universal sealing capability whilst the continuous reset and the constant pressure of the encapsulation onto the sealing point is performed by the core. As a result, there is a huge sealing compression that increases with media pressure.
In summary, the following are the main features of encapsulated O-rings:
- They offer a high chemical resistance.
- They function in a wide temperature window.
- They can withstand high-pressure-bearing situations.
- Their surface is low friction and has a low absorption of solvents.
- They enjoy high resistance to “COMPRESSION SET“.
- Their capacity for watertightness exceeds that of other seals.
- They can be described as being similar to an elastomer with a “teflon” coating.