GB2287997A

GB2287997A - A connector for a plastic coated conduit

Info

Publication number: GB2287997A
Application number: GB9503723A
Authority: GB
Inventors: Graeme Kenneth Speirs
Original assignee: POLYMER Ltd
Current assignee: POLYMER Ltd
Priority date: 1994-02-25
Filing date: 1995-02-24
Publication date: 1995-10-04
Anticipated expiration: 2015-02-24
Also published as: GB9503723D0; GB2287997B; GB9403698D0

Abstract

A metal conduit 24 forming part of a subsea control line has a protective plastics coating 26. The conduit 24 is coupled to a fixed part 16 such as another control line or other apparatus by a connector body 10 and a lock nut 20. A first ferrule 28 provides a wedging fluid seal between the connector body 10 and the plastics coating. Second and third ferrules 30, 32 engage the metal conduit 24 to seal the bore of the conduit 24 and to secure the conduit mechanically. <IMAGE>

Description

A Connector This invention relates to a connector and in particular, but not exclusively, a connector used with an encapsulated control line.

Control lines for use in downhole or subsea applications generally comprise one or more metal tubes containing fluid, an electrical conductor, fibre optics or cable to operate apparatus, such as control valves in the well or inflatable packers. In addition, such control lines can be used to inject chemicals into the well, or to convey signals from downhole equipment to the surface. Conventionally, the metal tubes are encapsulated in a layer of an extrudable polymeric material which forms a sheath to protect the metal tube from chemical corrosion and mechanical damage in the sub-sea environment or in the borehole or well.

However, where a control line is coupled either to a connection on apparatus or to another control line, it is necessary to remove the protective coating from the end of the control line being connected. This will generally leave a bare portion of the metal tube in the vicinity of the coupling point which is not protected by the polymeric coating and is therefore vulnerable to corrosion.

This is a particular problem with control lines which contain fluids under pressure, as baring of the metal tube is necessary to obtain a connection which is pressure tight.

Use of a standard compression fitting acting directly onto a coated tube is found not to produce a satisfactory fluid seal as the polymer coating is extruded by the fluid pressure.

According to the present invention there is provided a connector providing a primary fluid seal and a secondary fluid seal with a body connected thereby; wherein said connector comprises a coupling body having a through bore and having a first end adapted to engage a connector member, and a second end adapted to receive a locking member, the body to be connected extending, in use, through said bore; the connector further including first sealing means whereby a fluid seal is established between said body and said connector member, and second sealing means whereby a fluid seal is established between said body to be connected and said coupling body.

Typically, the body to be connected may comprise a conduit.

More specifically the invention provides a connector for coupling a conduit to an object for fluid communication between the conduit and the object, the conduit having a coating on its external surface, the connector comprising a coupling body having a through bore through which the conduit may extend, the coupling body having a connection means at a first end for connection to the object and a connection means at a second end; first sealing means located in the coupling body for engaging the external surface of the conduit to provide a fluid seal, when the connection means at the one end of the body section is coupled to the object, to substantially prevent loss of fluid from the conduit; a locking member through which the conduit extends, the locking member being adapted to engage the connection means at the other end of the coupling body; and a second sealing means located between the coupling body and the locking member, the second sealing means engaging the coating on the conduit in use to substantially prevent fluid outside the coupling body contacting the external surface of the conduit between the first and second sealing means.

Preferably, said first end of the coupling body is provided with an annular recess for engaging said connector member and housing said first sealing means.

Preferably also, said first sealing means comprise first and second ferrules, wherein said first ferrule is provided with a sloping surface, in use, mutually engaging a surface of said connector member.

More preferably, the first ferrule abuts a first surface of said second ferrule and a second surface of said second ferrule abuts a shoulder of said annular recess.

Most preferably, the locking member is provided with an annular recess for engaging said second end of the coupling body and housing the second sealing means.

Preferably, the second sealing means comprises a ferrule having a sloping surface, in use, mutually engaging said second end of the coupling body and a surface abutting a shoulder of said annular recess.

More preferably, said body to be connected is provided with a coating which is engaged by the second sealing means, the first sealing means engaging the external surface of the body. Typically, the coating may comprise a polymeric material, which is preferably extrudable onto the external surface of the body to be connected.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing, which is a schematic side view, partly in section, of a connector in accordance with the invention.

Referring now to the drawing, a connector embodying the invention comprises a generally cylindrical connector body 10, having a first internally threaded end 12 and a second externally threaded end 14, a male connector 16 having an externally threaded portion 18 adapted to be received in said internally threaded end 12 of the connector body 10, and an internally threaded lock nut 20 adapted to engage said externally threaded end 14.

A through bore extends through said connector body 10, said male connector 16 and said lock nut 20 when assembled. An annular shoulder 22 extends around the interior of the bore in the connector body 10.

The body to be connected in this example is a control line which comprises a metal tube 24 with a protective coating 26. The metal tube 24 passes through the lock nut 20, the coupling body 10, and the male connector 16. In the assembled connection, a first ferrule 28 is located on the tube 24 between the lock nut 20 and the externally threaded end 14 of the connector body 10, and second and third ferrules 30 and 32 are located on the tube 24 between the male connector 16 and the annular shoulder 22. The ferrules 28,30,32 cooperate with the connector body 10, the male connector 16 and the lock nut 20, in use, to create first and second fluid seals as shall be described in more detail below.

The male connector 16 is attached to the coupling body 10 by screwing the externally threaded end 18 into the internally threaded end 12 of the coupling body 10.

Face 34 of the male connector 16 abuts with the second ferrule 30 which in turn acts against the third ferrule 32. Further movement is prevented by the third ferrule 32 abutting the shoulder 22. The wedging force created by the inward movement of the male connector 16 acting against the ferrules 30 and 32 causes the ferrules 30 and 32 to compress against the metal tube 24, thus creating a seal at the connective junction between end 18 of the male connector 16 and the metal tube 24.

The lock nut 20 is rotationally fixed to end 14 of the coupling body 10. Movement of the first ferrule 28 against end 14 of the coupling body 10 creates a wedging force which compresses the ferrule 28 against the coating 26. This provides a fluid seal preventing external fluids contacting the exposed portion of the metal tube 24. The protective coating 26 protects the metal tube 24 against the action of corrosion which could result in failure of the control line.

Control lines, such as that described above, may be used in downhole applications such as operation by remote control of apparatus permanently installed at the mud line (or sea bed) or used to inject chemicals into wells. The connector of the present invention can be used with such lines to minimise the likelihood of failure due to corrosive damage occurring at the connective junction.

Claims

1. A connector providing a primary fluid seal and a secondary fluid seal with a body connected thereby; wherein said connector comprises a coupling body having a through bore and having a first end adapted to engage a connector member, and a second end adapted to receive a locking member, the body to be connected extending, in use, through said bore; the connector further including first sealing means whereby a fluid seal is established between said body and said connector member, and second sealing means whereby a fluid seal is established between said body to be connected and said coupling body.

2. A connector according to claim 1, in which the body to be connected comprises a conduit.

3. A connector for coupling a conduit to an object for fluid communication between the conduit and the object, the conduit having a coating on its external surface, the connector comprising a coupling body having a through bore through which the conduit may extend, the coupling body having a connection means at a first end for connection to the object and a connection means at a second end; first sealing means located in the coupling body for engaging the external surface of the conduit to provide a fluid seal, when the connection means at the one end of the body section is coupled to the object, to substantially prevent loss of fluid from the conduit; a locking member through which the conduit extends, the locking member being adapted to engage the connection means at the other end of the coupling body; and a second sealing means located between the coupling body and the locking member, the second sealing means engaging the coating on the conduit in use to substantially prevent fluid outside the coupling body contacting the external surface of the conduit between the first and second sealing means.

4. A connector according to claim 3, in which said first end of the coupling body is provided with an annular recess for engaging said connector member and housing said first sealing means.

5. A connector according to claim 4, in which said first sealing means comprise first and second ferrules, wherein said first ferrule is provided with a sloping surface which, in use, engages a cooperating surface of said connector member.

6. A connector according to claim 5, in which the first ferrule abuts a first surface of said second ferrule and a second surface of said second ferrule abuts a shoulder of said annular recess.

7. A connector according to any of claims 3 to 6, in which the locking member is provided with an annular recess for engaging said second end of the coupling body and housing the second sealing means.

8. A connector according to claim 7, in which the second sealing means comprises a ferrule having a sloping surface which, in use, engages said second end of the coupling body, and further comprises a surface abutting a shoulder of said annular recess.

9. A connector according to claim 1 or claim 2, in which said body to be connected is provided with a coating which is engaged by the second sealing means, the first sealing means engaging the external surface of the body.

10. A connector according to any of claims 3 to 9, in which the coating comprises a polymeric material.

11. A connector according to claim 10, in which the polymeric material is extrudable.

12. A connector substantially as herein described with reference to and as shown in the drawings.