Pipe joints or couplings – Movable jaw
Reexamination Certificate
2000-10-31
2003-04-29
Knight, Anthony (Department: 3679)
Pipe joints or couplings
Movable jaw
C285S123900, C285S123110, C285S900000, C285S920000
Reexamination Certificate
active
06554324
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for connecting tubular members and a method for achieving the same. In particular, the present invention relates to an apparatus and method for connecting tubular members of use, for example, in oil field applications.
BACKGROUND OF THE INVENTION
In many operations the need arises to connect tubular members, such as pipes for carrying fluids. This is particularly the case in oil field operations, especially in offshore operations for the exploration or production of hydrocarbons. One particular need for means to connect tubular members arises during offshore operations when it is desired to connect a riser from the surface structure or vessel to a wellhead located on the sea floor. The development of deep draft caisson vessels (DDCV) and tension leg platforms (TLP) has led to a need for the subsea wellhead installations and the riser systems to be of a compact design, in order to reduce weight, and space and loading requirements. A number of designs of connectors for use in oilfield applications have been proposed, details of which are as follows.
U.S. Pat. No. 3,322,443 discloses a quick coupling device for tubular bodies comprising a male member having a pin portion and a female member having a socket for receiving the pin portion of the male member. A nut is threaded onto the outer portion of the pin portion of the male member and carries on its outer surface a series of cams. The cams on the outer surface of the nut cooperate with corresponding cams on the inner surface of the socket portion of the female member when the pin portion is inserted into the socket. Rotation of the nut brings the cams on its outer surface into engagement with the cams on the inner surface of the socket, the action of which is to urge the male and female members towards each other in the axial direction. This connector requires special members to be formed on both of the tubular bodies to be joined in order to provide the male and female members. Such a connector could not be used to join existing, standard members, such as risers and wellheads.
U.S. Pat. No. 3,986,729 discloses a connecting apparatus for releasably connecting with the end of a tubular member. The connector comprises a connector body having a seating surface for engaging with a complementary seating surface on the tubular member. The connector further comprises a discontinuous locking ring having a conical locking surface. The locking ring is expandable and contractible in a circumferential direction, allowing it to be moved into and out of engagement with a locking shoulder on the tubular member. In a one embodiment, the locking ring is carried by the connector body for engagement with a locking shoulder disposed on the outer surface of the tubular member. In a second, alternative embodiment, the locking ring is carried so as to be engagable by radially outwards movement with a locking shoulder disposed within the tubular member.
A pipe coupling is disclosed in U.S. Pat. No. 3,997,199 mountable on the external surface of a pipe. The coupling comprises a tapered compression ring and a split ring slip having a taper cooperating with that on the compression ring. A set screw is used to cause the split ring slip to move in an axial direction, the taper on the ring slip acting to urge the compression ring against the outer surface of a pipe place in the coupling. The pipe coupling of U.S. Pat. No. 3,997,199 is secured, for example by welding, to the outside of the pipes being coupled, thereby leading to a significant increase in the diameter of the pipe assembly in the region of the coupling.
U.S. Pat. No. 4,049,297 discloses a pipe coupling apparatus also employing a series of tapered slips or collets. In the device of U.S. Pat. No. 4,049,297, a first elongated housing encloses tapered slips or collets, which work against a tapered portion of the inner surface of the first housing. Hydraulic pressure is used to drive a piston to slide the collets against the taper of the housing, in turn forcing the collets against the outer surface of a first pipe. A second housing encloses the end portion of a second pipe. A piston is disposed within the second housing in connection with a hydraulic system. The piston has a tapered portion, which, under the action of the hydraulic system, is moved to engage with a tapered clamping ring. The clamping ring is thereby moved to engage with suitably formed grooves in the exterior of the first and second pipes, in order to draw the ends of the pipes into contact. Again, the coupling of U.S. Pat. No. 4,049,297 is applied to the exterior of the pipes being coupled and relies upon profiles formed on the outside of the pipes, resulting in an increased diameter of the pipe assembly.
A tubular connector is also disclosed in U.S. Pat. No. 4,265,470. The connector requires a shoulder on the outer surface of a first tubular member to be connected. A collet extends around the outer surface of the first tubular member and engages with the shoulder. The collet comprises a plurality of axially extending fingers, having internal ridges for engaging with corresponding ridges in the outer surface of a second tubular member. A lock ring is used to secure the fingers of the collet into engagement with the ridges in the outer surface of the second member and is retained by a lock nut threaded onto the outside of the second member. This coupling requires the tubular members being connected to be machined in order to provide the essential elements of the connector assembly.
A further coupling disclosed in U.S. Pat. No. 4,372,584 comprises a male member and a female member for connection to the outside of respective first and second pipe sections. The male member comprises a locking member having a locking sleeve comprising a plurality of bendable locking fingers extending in an axial direction from the locking sleeve. A piston is provided to displace the free ends of the locking fingers radially outwards into engagement with the female member. The free ends of the locking fingers bear against an inner surface of the female member, with the effect of drawing the ends of the two pipe sections together. The female member is shaped to allow the locking fingers to be displaced to an over center position. The coupling disclosed in U.S. Pat. No. 4,372,584 is employed on the outside of the pipes being coupled, thus adding substantially to the overall diameter of the pipe assembly. The coupling dos not utilize existing profiles on the pipes being connected, in particular profiles on the interior surface of the pipes. In addition, it would appear that, once the locking fingers having moved into the over center position, there is no means for unlocking the coupling and disconnecting the pipes.
A wellbore lock system is disclosed in U.S. Pat. No. 5,617,918. The lock system comprises a radially moveable engagement member. The engagement member is moved from a first retracted position to a second extended position by a sleeve, the engagement member engaging with a profile formed in a subsurface nipple when in the second position. A seal assembly is provided, in which a seal is expanded radially outwards by an actuation assembly in order to seal the union against fluid leaks.
There remains a need for an improved apparatus to connect tubular members, such as pipes and subsea risers. It would be advantageous if the improved apparatus would be able to be configured in an arrangement of minimal diameter. Preferably, such an apparatus would engage with pre-existing profiles on the interior surface of an existing tubular member, for example a subsea wellhead. It would be further advantageous if such an apparatus could be operated remotely, for example from the sea surface, and be releasable when desired, in order to disconnect the tubular members. Finally, it would be advantageous if the apparatus could employ existing, conventional tubular members, such as pipes, risers wellheads and the like, without any modification being necessary to provide the essential worki
Birlinski Peter A.
Collins G M
Cooper Cameron Corporation
Hartman Michael P.
Knight Anthony
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