Conduit joint and seal ring

#The present application claims priority from GB1009619.6, filed on Jun. 9, 2010, herein incorporated by reference in its entirety.

#1. Field of the Invention

#The present invention relates generally to an improved ball and socket conduit joints for connecting two misaligned conduits in fluid-tight communication, and to a metal seal ring for use therein.

#Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.

#FIG. 1 shows a partial section of an assembled joint according to the present invention.

#FIG. 2 is a close-up view of portion A in FIG. 1 showing the cross section of the seal ring in more detail.

#As shown in FIG. 1, socket member comprises a metal housing 1 and a metal retaining ring 2 which on installation are clamped together by metal studs and nuts 9. The socket member has a substantially spherical inside surface including a first seal seat on the inside of the housing 1. A metal ball member 3 has a substantially spherical outside surface for engagement by the substantially spherical inside surface of the socket member. The shape and dimensions of these parts are such that there is radial tension and compression therein at an interface 15 when the nuts 9 are tightened. In this manner the joint can be locked at the misalignment angle.

#As also shown in more detail in FIG. 2, the ball member has an annular nose portion 4 to which a metal seal ring 5 is secured by many (e.g. 28) bolts 8 sufficient to pre-energize the seal ring into the ball member 3.

#The nose portion 4 includes a second seal seat. The seal ring 5 is of frusto-conical tubular form and has a substantially uniformly tapered bore and has on an outwardly facing surface a first sealing surface 7 for sealing engagement with said first seal seat, a second sealing surface 6 for sealing engagement with said second seal seat and an annular protrusion which is located between the first and second sealing surfaces and extending outwardly towards but not reaching the first seal seat on the inside of the housing 1. The bolts 8 pass through apertures in said annular protrusion and secure said annular protrusion to said nose portion and are tightened during manufacture sufficiently to pre-energize the seal ring into the ball member 3. The cone angle determines the maximum degree of misalignment (shown in FIG. 3 as 10°) between conduits. The radius of the second sealing surface is slightly less than the radius of the first seal seat of the housing member 1 to reduce the contact area and thus increase the contact pressure and fluid pressure the seal can withstand. An auxiliary or secondary seal is provided at 14.