New metal to metal seal concept achieves high performance at ultra-high temperatures

Garlock Sealing Technologies has developed a new metal-to-metal seal concept which enables service temperatures of 1,000C to be achieved with low seating loads. Achieving high sealing tightness at ultra-high temperatures, ULTRASEAL extends the design boundaries for engineers normally constrained by the need for bulky high-load bearing flanges.

ULTRASEALs construction is based around a graphite core which provides excellent springback and deflection properties as well as an ability to withstand temperatures beyond 1000C. The die formed graphite ring is controlled by two metal cups moving axially relative to one another during seal compression.

The graphite ring and metal cup assembly is encapsulated by hermetically laser-welding to prevent any risk of high temperature oxidation (the reason exposed graphites upper 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 involving CEA (the French Atomic Energy Commission), Garlock, and six other R&D and industrial partners, ULTRASEAL is aimed at meeting the design needs of engineers within the power generation, chemical, petrochemical and aerospace industries.