US Patent 7445047 Metal-to-metal non-elastomeric seal stack

An improved seal assembly for use in sliding sleeve valves. The seal assembly incorporates a number of annular, chevron-shaped seal elements that are in a stacked configuration and preferably formed of a thermoplastic material to provide a fluid seal between the outer housing and the inner sleeve member of the sliding sleeve valve. In addition, the seal assembly preferably includes a pair of annular metallic seal members that have a C-ring cross-section (a “C-seal”). On opposite axial sides of each metallic C-seal are a C-seal support ring and an end adapter that are shaped and sized to assist the metallic C-seals to be axially compressed and uncompressed to resiliently seal against both the inner sleeve member and the outer housing.