Technial article:Installation of encapsulated o-rings

Encapsulated o-rings installation instructions:

1, The parts that are to be fitted or coated with O-rings are required to be smooth, burr-free, notched and sharp, with a bore profile of 20 mils and an axial profile of 10 mils.
2, with a clean light oil or grease coated o-rings lubricate the surface and its contact with the relevant parts.
3, coated O-ring mounted on the shaft more difficult, it can be immersed in hot water for a few minutes to expand, the softened and expanded O-ring installation easier. Install this O-ring when hot and cool down to its original size.
4, do not be too drastic bending coated O-ring, otherwise it will affect the use of Teflon folds.

Coated o-rings requirements of compression is as follows:

Static seal status: 15% -20%
Dynamic seal status: 10% -12%

Pneumatic state: 7% -8%

Coated o-rings with both PTFE chemical resistance and rubber elasticity, made of plastic coated outer layer of rubber, almost all chemical resistant media (soluble alkali metal, high temperature fluorine and chlorine trifluoride ( CIF3) except)
Mainly used in pumps and valves, heat exchangers, boilers, filters, reaction vessels, pressure vessels, pipe flanges, mechanical seals, gas compressors, extraction equipment.

There are three outer plastic:

1, FEP, temperature -20 ℃ ~ 200 ℃, Universal;
2,PFA (polyfluoro-band alkoxy), temperature -20 ℃ ~ 260 ℃, high temperature type;
3, double polytetrafluoroethylene, high and low temperature, -50 ℃ ~ 260 ℃, special corrosion;

There are two main types of inner rubber:

1, silicone rubber (SIL)

2, fluorine rubber (FKM)

Others such as NBR, EPDM need to be customized.