Patent ID: 7347455
Filing Date: 2008-03-25
Classification: E21B,F16L,Y10S

Abstract:
1. A riser assembly, comprising; a) a central pipe having a first diameter, an inner surface, an outer surface, an open ended bore, a wall thickness and opposed ends; b) a plurality of peripheral pipes, each having an open ended bore and a second diameter that is smaller than the first diameter; c) at least one flange that joins the central pipe and peripheral pipes together to define a multi-pipe structure, said at least one flange having a central opening occupied by the central pipe and a plurality of circumferentially spaced apart peripheral openings that generally surround the central opening, at least some of said peripheral openings being occupied by a said peripheral pipe, said structure having opposed end portions, one said end portion being a pin end portion; d) a protective cover affixed to the central pipe, said cover being a polymeric body that includes an inner cylindrical portion that occupies a part of said open ended bore of said central pipe and being next to the inner surface of the central pipe and an outer cylindrical portion that surrounds one of said opposed ends of said central pipe, a shoulder that connects the inner and outer cylindrical portions of said polymeric body, a circular disk that is connected to the inner cylindrical surface and that occupies a position in the bore of the central pipe; e) said cover including a plurality of radially extending enclosures that each are connected to and extend from the outer cylindrical portion to the periphery of one of the flanges next to the pin end portion, each said enclosure comprising a longitudinally extending wall connected to the outer cylindrical portion and a transversely extending wall that is connected to the longitudinally extending wall and to the outer cylindrical portion, each enclosure having an edge that is positioned next to said next to said one of the flanges next to the pin end portion flange; and f) wherein each peripheral pipe has a free end that is enveloped by one of said plurality of radially extending enclosures.