Valve seat ring having a corner groove to receive an elastic seal ring

A valve comprising:

• a. a housing with a longitudinal bore therethrough,
• b. a valve chamber intersecting said bore,
• c. a valve member mounted within said valve chamber for movement between open and closed portions,
• d. a pair of facing annular recesses surrounding said bore at said valve chamber, each of said recesses having an end wall joining said bore and an annular wall coaxial with said bore joining said end wall and said valve chamber,
• e. a pair of seat ring members loosely mounted within said annular recesses for floating back and forth movement in said recesses, each of said seat ring members having an outer circumference comprising a pair of generally parallel inner and outer stepped peripheral surfaces, a radially disposed outwardly facing annular surface connecting the stepped peripheral surfaces, and a radially disposed seat end surface joining said inner stepped peripheral surface and the internal bore of said seat ring member, said seat ring member having a peripheral groove at the juncture of said inner stepped peripheral surface and said radially disposed outwardly facing annular surface, said groove having a pair of generally parallel opposed sides respectively joining said inner stepped peripheral surface and said radially disposed outwardly facing annular surface at obtuse angles,
• f. a seal ring chamber between each of said seat ring members and the end wall of the associated annular recess, said seal ring chamber defined by said recess annular wall, said inner stepped peripheral surface, said radially disposed outwardly facing annular surface, and said recess end wall, and
• g. a resilient O-ring positioned within the seal ring chamber and having a cross-sectional span sufficient to seal between said recess end wall and said radially disposed outwardly facing annular surface when said O-ring is initially positioned in said seal ring chamber upon assembly of said valve, said groove sides being spaced apart a distance substantially approximately the original cross-sectional radius of said O-ring, the depth of said groove being at least equal to the original cross-sectional diameter of said O-ring to receive a portion of said O-ring between said generally parallel sides when said O-ring is subjected to mechanical compression between said recess end wall and said radially disposed outward facing annular surface so said O-ring is squeezed no more than approximately 35 percent between said end wall and said radially disposed outwardly facing annular surface in order that the elastic limit of said O-ring is not exceeded, said radially disposed seat end surface contacting said recess end wall to limit outward movement of said seat ring member when the groove has received a portion of said O-ring with said O-ring being in fluid-tight sealing contact with said recess end wall, said radially disposed outwardly facing annular surface, and said groove sides.