an annular expander ring in said groove radially inward of {HEAD ~ said seal ring}, said expander ring having a conical outer ring surface engageable with a radial inner side of {TAIL ~ said seal ring} and a continuous radial sealing surface on one axial side thereof engageable with one of said groove sealing wall surfaces whereby said expander ring exerts a radially outward force on said seal ring 
an annular expander ring in said groove radially inward of { HEAD ~ said seal ring } , said expander ring having a conical outer ring surface engageable with a radial inner side of { TAIL ~ said seal ring } and a continuous radial sealing surface on one axial side thereof engageable with one of said groove sealing wall surfaces whereby said expander ring exerts a radially outward force on said seal ring
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH