Abstract:
An assembly and method for stiffening a flexible member according to which a stiffening member and an adapter surround the flexible member and an insert extends in an annulus between the adapter and the flexible member.

Description:
BACKGROUND 
     This invention relates to an assembly and method for stiffening a flexible pipe. 
     Flexible pipes, or other flexible components such as tubes, risers, umbilicals, cables, and the like (hereinafter collectively referred to as “flexible members”) are often subjected to substantial bending moments. For example, when flexible members are used in subsea operations to transfer fluids, the hydrodynamic effects of water current can cause substantial bending moments on the flexible members, especially at their termination points. This can lead to fatigue failure in the flexible member. 
     To guard against any damage that would be caused by these bending moments, bend stiffeners are often placed around the flexible members to increase their stiffness and thus decrease the bending moments. A typical bend stiffener is formed by an elastomer tapered sleeve that extends around the flexible pipe and is secured to the pipe by an adapter. However, the internal diameter of the adapter usually engages the outer surface of the flexible member, which can cause excessive wear on the flexible member that could compromise its integrity. 
     Therefore, what is needed is an adapter for a flexible member that eliminates this problem. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial elevational/partial cross-sectional view of an assembly according to an embodiment of the invention. 
         FIG. 2  is a top plan view of the assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a flexible member, in the form of a pipe  10 , is shown, and it is understood that it is disposed in an environment in which it is subjected to the bending moments discussed above. A cylindrical bend stiffener  12  surrounds a portion of the pipe  10  that needs to be stiffened, such as a joint between two adjacent sections of the pipe, an area near a termination point of the pipe, or the like. The inner surface of the bend stiffener  12  is in contact with the corresponding outer surface of the pipe  10 , and it is understood that the outer surface of the remaining portion (not shown) of the bend stiffener  12  can be tapered slightly in a direction towards the pipe. Preferably, the bend stiffener  12  is fabricated from an elastomer material, such as polyurethane or polychloroprene. 
     A mounting ring  16  extends around the pipe  10  and is bolted to the upper end of the bend stiffener, as viewed in  FIG. 1 . 
     The lower end of a cylindrical adapter  20  is welded to the upper surface of the ring  16  by an annular weldment  22 . The inner diameter of the adapter  20  extends in a spaced relation to the corresponding outer surface of the pipe  10  to form an annulus which receives a cylindrical insert  24 . The inner surface of the insert  24  is in contact with the corresponding outer surface of the pipe  10 , and the outer surface of the insert is in contact with the corresponding inner surface of the adapter  20 . The inner surface of the lower end portion of the insert  24  is welded to the lower end of the adapter  20  and to the upper surface of the ring  16  by an annular weldment  26 . 
     The insert  24  is split, e.g., it is formed by two sections  24   a  and  24   b  ( FIG. 2 ), each having a semi-circular cross section, to facilitate the assembly of the insert in the above annulus between the pipe  10  and the adapter  20 . Preferably the insert  24  is fabricated from polyurethane. 
     The outer surface of the insert  24  is stepped ( FIG. 1 ), and an annular tapered flange  30  is welded to the shoulder formed at the step. In the event an outer tube structure (not shown) is placed around the pipe  10 , or a portion of the pipe, above the bend stiffener  12 , the flange  30  permits an enlarged mouth of the tube structure to be secured to the adapter  20  and the bend stiffener  12  by a tube bellmouth system (not shown). 
     An annular flange  24   a  extends radially outwardly from the upper end of the insert  24 , and four padkeys  32   a – 32   d  ( FIG. 2 ), spaced at ninety degree intervals, are bolted to the flange to receive a tow line, or the like (not shown). 
     The assembly formed by the bend stiffener  12 , the adapter  20 , and the insert  24  stiffens the portion of the pipe  10  extending within the assembly while the insert eliminates any engagement, and resultant wear, between the adapter and the pipe. 
     It is understood that variations may be made in the above, without departing from the scope of the invention. For example, spatial references, such as “upper”, “lower”, “vertical”, “angular”, “radial” etc. are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above. Also, the weldments  22  and  26  can be replaced by any other type of connectors such as bolts, etc. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.