U.S. Patent No. 7,497,443 (LEW 17,166-1) was issued to Dr. Bruce Steinetz and Mr. Pat Dunlap of the Structures and Materials Division for their invention entitled, “Resilient Flexible Pressure-activated Seal.” The patent describes a structural seal that combines both metal and ceramic materials to achieve greater levels of temperature, resiliency and compliance characteristics relative to conventional formed C-shaped metal seal designs.
Greater compliance and flexibility is achieved by fabricating the C-shape jacket from sheet metal segments fashioned in a “comb-like” structure and “nested” together. Internal and external laminates are indexed to “cover” and therefore seal the gaps of the adjacent layer. Added flexibility is desired to seal variable gaps that may occur between adjacent structures due to either mechanical or thermal loads. The opening of the “C-shape” is positioned toward the high pressure zone allowing the pressure to aid in seating and therefore sealing the seal against the sealing surfaces.
For higher temperature applications, the open cavity of the “C-shape” is filled with either simple ceramic insulation or braided/woven textile structures fashioned of high temperature ceramic fibers to insulate the metal segments from the high temperature gas. Combining the insulating element with the metal seal element allows higher operating temperatures for the metal seal than otherwise would be possible.
Applications of this seal include high temperature structural joints in either aerospace structures (airframes, propulsion systems) or industrial components (furnaces, other) requiring high temperature seals. This work was originally funded by NASA’s Next Generation Launch Technology Project (NGLT).
