Pipe fitting having a non-metallic sealing member

Claim 1

A pipe fitting comprising in combination: an externally threaded tubular male member having a non-metallic lining at the interior surface thereof; an internally threaded female member threadedly interconnected to said male member; a non-metallic ring comprising a tubular body, a radial flange extending substantially generally transversely outwardly from said tubular body and a thread engaging sealing portion extending generally radially outwardly from said radial flange; said sealing portion having an outer periphery having a diameter greater than the minor diameter of the threads of said female member; said sealing portion being defined by a lip having a thickness which decreases along the transverse axis of said ring to a minimum thickness at the outer edge of said lip; a part of said sealing portion being adapted to be disposed between opposed thread flanks of said male member and said female member as said male member and said female member are brought into threaded engagement, the space between said opposed thread flanks being substantially filled by said part of said sealing portion to thereby provide a seal at said opposed thread flanks; said tubular body of said ring being disposed in said tubular male member in close engagement with the non-metallic lining thereof; said radial flange of said sealing portion being disposed over the end wall of said lining and the end wall of said tubular male member and in close contact therewith whereby, said ring serves to isolate said tubular male member from contact with fluid conducted by said member.