Ultra high temperature seal
19 Apr 2004
A new metal-to-metal sealing system from Garlock Sealing technologies enables service temperatures of 1000 degrees C to be achieved with low seating loads.
Removing the constraints of bulky, high-load bearing flanges, the Ultraseal is based around a graphite core that is said to provide excellent 'springback' and deflection properties, as well as the ability to withstand temperatures beyond 1000 degrees C.
The die-formed graphite ring is controlled by two metal cups, which move axially relative to one another during seal compression. The graphite ring and metal cup assembly is hermetically laser-welded together to prevent any risk of high temperature oxidation (the reason exposed graphite's upper graphite temperature limit is substantially reduced).
The whole assembly is then sealed within an envelope of the actual sealing substrate, depending on the application. The sealing function relies on the ridges machined on the external face of the spring metal cups acting through the sealing envelope. This concentrates the seating load over a limited contact area, thus maximising seating stress.
The result of a three-year European collaboration project between Garlock, the French Atomic Energy Commission (CEA) and six other R&D and industrial partners, Ultraseal is aimed at engineers in the power generation, chemical, petrochemical and aerospace industries.
