Fluid seal

Claim 1

A valve for controlling fluid flow comprising: a. a valve casing having a fluid passage therethrough, one end of said casing having an annular notch adjacent the pasage and, a shoulder adapted to receive a retaining ring; b. a retaining ring removably secured to said shoulder, said ring and notch defining a groove adapted to receive a sealing strip; c. a sealing strip, said strip positioned in the groove and adapted to be compressed by an obturator, said strip including: a sealing face adapted to cooperate with an obturator; a pair of oppositely disposed spaced-apart side faces extending from said sealing face, each of said side faces having a slot therein distortable when said sealing strip is compressed by said obturtor, each slot overlapping the other slot without interfering with the other slot; and a base extending between said side faces, the width of said base being greater than the width of either of the slots; d. a deformation-limiting means disposed in each slot, said means cooperating with said sealing strip to limit deformation of said strip; e. a stem rotatably disposed in said passage and extending through said casing; and, f. an obturator secured to said stem for movement therewith, said obturator compressingly engaging said sealing strip to regulate fluid flow through the passage.