PTFE U-ring fits solid glands
T he Turcon Variseal SA from Trelleborg
Sealing Solutions provides a PTFE based metal sprung U-seal that can be used in the solid glands preferred by aerospace engineers.
The seal offers easy installation combined with high temperature operation, chemical resistance and low friction, making it suitable for high frequency applications such as flight controls.
A solid gland design, of a groove machined directly in a housing component is often preferred to simplify installation. Slipper seals, energized by an elastomer can fit into these without a problem. However, spring energized seals such as the Variseal is often a preferred sealing option, because it has a number of advantages in aircraft applications. Its is capable of operating in extremes of temperature and is resistant to aggressive aerospace fluids such as synthetic hydrocarbon, petroleum base, phosphate ester and all types of aviation jet fuels. It also has a very low coefficient of friction, which optimizes sealing load, making it ideal for the high frequency cycling of primary flight controls.
During installation into a solid gland, seals need to be compressed substantially. Due to the lip configuration of typical PTFE U-seals, the spring energizer within it tends to flare its jacket outwards. This makes installation very difficult without a split gland, especially in