TOROIDALLY STRESSED ANNULAR SEALS

摘要

A method of sealing an annular gap and a sealing arrangement suitable for plug valves, shafts and pistons. An annular sealing member is toroidally rotated through a substantial angle prior to or during insertion in the gap to be sealed, and is arranged so as to be free to react toroidally against the sealing surfaces bounding the gap for positive sealing engagement therewith. In this way the sealing member forms a resilient seal for the gap without being subject to significant radial stresses. An important application of the invention is to seat seals for ball plug valves.