WO2016038396A1

WO2016038396A1 - Flow line connector assembly

Info

Publication number: WO2016038396A1
Application number: PCT/GB2015/052653
Authority: WO
Inventors: David Ernest Mckay
Original assignee: Subsea Technologies Limited
Priority date: 2014-09-14
Filing date: 2015-09-14
Publication date: 2016-03-17
Also published as: GB201705893D0; NO20170624A1; GB2545852B; GB2545852A

Abstract

A flow line connector assembly comprises a socket and plug (6), the socket and plug (6) being disposed on first (5) and second (20) parts of the connector and having planar and rectilinear cross-sections. The assembly includes a locking device to prevent disconnection of the first (5) and second (20) parts when the tension across the connector is below a given threshold, and an emergency disconnect system that acts to disconnect the first (5) and second (20) parts when tension across the connector exceeds the tension threshold.

Description

TITLE: FLOW LINE CONNECTOR ASSEMBLY

This invention relates to a flow line connector assembly, and particularly to a flow line connector assembly in a subsea flow line used to convey a fluid to or from a subsea well.

It is frequently necessary to convey fluid between a subsea well and the surface. When conveying fluid to the well, a flow line is normally deployed from a support vessel on the surface, or from a platform, to the seabed, and is optionally ballasted near the flow line terminal connector on the end of the flow line within reach of a well. The subsea stack on the seabed at the wellhead normally has a mating connector adapted to connect to the terminal connector in the end of the flow line in order to make up the connection.

Summary Of The Invention

According to the present invention there is provided a flow line connector assembly having first and second parts, the first part having a mating portion comprising a plug and the second part having a mating portion comprising a socket configured to receive the plug, the assembly having a restraining device to resist disconnection of the first and second parts when the plug is received in the socket, wherein the socket and plug have respective conduits being configured to interconnect between the first and second parts when the plug is received in the socket, wherein the socket comprises at least one inner wall configured to engage with at least one outer wall of the plug when the plug is received in the socket, and wherein each of the inner wall of the socket and the outer wall of the plug comprises at least one planar section.

Optionally the socket and plug have respective bores comprising conduits for fluid flow through the first and second parts. The bores can be configured to

interconnect to form a conduit for fluid to flow between the first and second parts when the plug is received in the socket. The inner wall of the socket and the outer wall of the plug are optionally side walls, and the planar sections optionally extend parallel to the side walls and optionally parallel to the axis of the connector assembly.

The planar section can comprise a face or a part of a face. The planar section is optionally flat. The planar sections on the plug are optionally parallel to the planar sections of the socket. Optionally the first and second parts comprise end terminations of a flow line.

Optionally the ends of the first and second parts opposite to the mating portions are configured to connect to a fluid flow line. Optionally the connector assembly is configured to be used on a submerged flow line, optionally connecting a surface supply of fluid to a subsea location, optionally an offshore well having a wellhead on the sea bed.

Optionally the planar sections are polygonal.

Optionally, the inner wall of the socket, and the outer wall of the plug each optionally comprises at least two planar sections. On each of the plug and the socket, the planar sections can be arranged in sets of two, optionally on opposing and optionally parallel sides of the plug and the socket. For example, the wall of the plug can have two planar sections (e.g. faces) on opposite sides of the plug, which can be parallel to one another. Similarly, the wall of the socket can have two planar sections on opposite sides of the socket, which can be parallel to one another.

Optionally, more than two planar sections (e.g. 3, 4, 5, or more) can be provided on each of the plug and the socket. Optionally, two sets of parallel faces can be provided on each of the plug and the socket, in a generally rectilinear arrangement. Optionally, each of the plug and the socket can have a generally rectilinear cross- section for example in the shape of a square or a rectangle. Optionally, more than two sets of two parallel faces can be provided on each of the plug and the socket, for example 3, 4, 5 or 6 or more sets of two parallel faces.

Optionally, the plug and the socket each have an axis, and the planar faces are parallel to the axis.

Optionally, planar faces converge at edges, which are optionally straight and parallel to the axis of the socket and the plug. Optionally the plug and the socket engage one another via guide surfaces, which extend axially along the connector assembly, optionally continuously, between opposite ends. The planar faces may be disposed on the guide surfaces. Optionally the guide surfaces are formed adjacent to the edges between adjacent planar sections.

Optionally, the restraining device comprises a recess on one of the socket and the plug, and a dog on the other. Optionally, the dog engages within the recess in order to resist relative axial movement of the plug and the socket when the restraining device is engaged. Optionally, the recess is provided on a planar face on a wall of the plug or the socket. The recess is optionally non-symmetrical about a long axis of the connector assembly, having a shoulder disposed at each end of the recess, the shoulders being optionally spaced apart from one another along the long axis of the connector assembly, and optionally being disposed at different angles. Optionally the shoulder nearest the free end of the first or second part is disposed at a steeper angle to the axis than the other shoulder.

Optionally the shoulder has an apex formed between the external wall of the plug and the recess, and the apex is optionally planar in at least one plane. Optionally the dog has a similar apex set at the same angle and planar in at least one plane.

Optionally the apexes form a straight line, perpendicular to the axis of the connector assembly, and parallel to one another. Optionally, the dog is provided on a lever arm, having a pivot link connecting the lever arm to one of the first and second parts. Optionally, the pivot link connects one end of the lever arm to the first of the second part, and the other end of the lever arm is optionally provided with a locking device configured to resist movement of the lever arm around the pivot link. Optionally, when the locking device is engaged with the lever arm, the dog is locked into the recess, thereby locking the restraining device in place and restricting or preventing disconnection of the first and second parts. Optionally the locking device restrains movement of the lever arms in the locked configuration. Optionally the locking device comprises a hydraulically actuated device, optionally a hydraulic cylinder, which optionally moves a key, optionally in a linear path, between an unlocked position in which the key allows free movement of the lever arms and a locked position in which the key restricts the movement of the lever arms. Optionally the key engages both of the lever arms, and thereby restrains relative movement of the dogs on the lever arms in relation to one another in the locked position.

Optionally the key can be actuated by a mechanism that is not hydraulic, for example, the actuator can be a mechanical actuator on the connector assembly and can be operated by a manipulator on an ROV that is used to make up the connector. Optionally the key can be actuated by a pivoting mechanism that translates rotational movement of the actuator around a pivot point on one of the connector parts into linear movement of the key in relation to the lever arms.

Optionally, the lever arm is pivotally connected to an external face of one of the plug and the socket, optionally the socket, and optionally, the external face to which the lever arm is pivotally connected is planar, i.e. flat. Optionally, two lever arms are provided and the external surfaces of the socket to which the lever arms are pivotally connected comprise at least two planar surfaces, which are optionally disposed on opposing sides of the socket, arranged in a generally rectilinear configuration. Optionally, each lever arm diverges from the pivot connection into two limbs, which are each connected to the same pivotal connection, but which diverge apart from one another, and engage opposing external faces of the socket, optionally parallel external faces on opposite sides of the socket.

The external faces of the socket can optionally be generally planar, and optionally rectilinear.

Optionally the restraining device is pivotally connected to the plug on opposing and parallel faces on the external surface of the plug, and the locking device is disposed on opposing and parallel faces on the external surface of the plug that are perpendicular to the faces with the pivotal connection to the restraining device. Optionally, the lever arms on the restraining device engage the opposing and parallel faces on the external surface of the plug that bear the locking device.

Optionally, the recess to engage the dog is provided in the plug. Optionally, the recess comprises a shoulder, optionally comprising a planar face, which may optionally be rectilinear. The shoulder in the recess optionally engages a face on the dog, which may also comprise a planar face, which can be rectilinear. Optionally, the inter-engaging faces on the recess and the dog can be arranged at the same angle. Optionally, the face on the recess which engages with the face in the dog is provided at the end of the recess nearest to the free end of the plug.

Optionally, the bores in the plug and the socket to permit fluid flow interconnect via a protrusion on one of the plug on the socket, which is received within a recess on the other. Optionally, the protrusion is provided on the plug, and the recess is provided on the socket, but this can be varied in different examples of the invention. Optionally, the protrusion and the recess receiving the protrusion are cylindrical. Optionally, the interconnection of the protrusion and the recess incorporates seals, advantageously annular seals such as O-rings or the like, which are advantageously disposed in annular (optionally circular) grooves extending around the cylindrical portions of the protrusion and/or the recess. Optionally the bores can be internal bores in the plug and socket, but in other aspects of the invention, the bores can optionally be external, mounted on an external surface of the plug and the socket. Thus conduit(s) need not pass through the centre of the connector and can optionally be mounted externally.

Optionally conduits can be fluid conduits, but could alternatively be different conduits, for example, conduits could be power conduits, or signal conduits such as cables. Optionally the connector assembly can comprise more than one conduit on a single assembly, and the conduits can be the same, e.g. they can all be fluid conduits, or the conduits on the connector assembly can be different, e.g. some can carry fluids, some power, some signals, etc.

Optionally each of the first and second parts incorporates a valve such as a check valve, which may optionally function automatically, or may optionally be functioned manually or under remote control. Optionally the valve can be biased by a spring or other resilient device, instead of or in addition to the remote control. Optionally, the manual functioning of a check valve is desired, the relevant part may incorporate a control line, either from the surface, or from the well. Optionally, control lines can be hydraulic control lines, and the check valves can be functioned hydraulically optionally from either the surface or from the well, or from both. Optionally, control lines from one side of the connector can be connected through the plug and socket by control lines extending through and meeting within the connection, allowing transmission of control signals across the connection assembly when it is made up. Accordingly, in certain examples, either or both of the check valves on opposite sides of the connection can be functioned via a control lines from either or both sides of the connection.

Optionally, the connector assembly incorporates a disconnect system reactive to tension, which disconnects the connection assembly above a tension threshold. Optionally, the disconnect system is reactive to tension across the connector assembly, i.e. between the two parts. Optionally the disconnect system comprises a trigger line connected between a trigger mechanism on the assembly and a part of the flow line spaced apart from the connector assembly. Optionally the trigger line is shorter than the length of flow line between the connector assembly and the trigger line connection to the flow line, whereby the trigger line is tensioned and activates the disconnect system on the connector assembly before the flow line between the connector assembly and the trigger line is subjected to excessive tension.

The connector assembly optionally has a locked configuration, when the first and second parts are engaged, and the locking device is locked. A hydraulic cylinder driving the movement of the key is optionally in a first operating position and the piston on the cylinder is optionally extended to engage the key with the lever arms and to retain the dogs in the recesses to enable the locked configuration.

The connector assembly can also adopt an unlocked configuration. In the unlocked configuration, the hydraulic cylinder is optionally still in the same first position, but the piston is retracted within the cylinder to pull the key axially out of engagement with the lever arms. The arms are optionally biased gently inwards by a resilient device such as a spring, so when the piston retracts into the cylinder to disengage the key, the dogs remain within the recesses under the force of the spring, but the plug can be pulled out of the socket pushing the dogs out of the recesses against the force of the spring, which is optionally relatively weak.

After the plug is clear of the socket the connector assembly is in a third unlocked and reset configuration. The plug has pushed the dogs aside on the way out of the socket and the dogs have then been urged back radially inwards by the spring. This is the normal resting position of the socket, which it adopts before the plug is once more re-engaged into the socket. The leading end dog-engaging shoulder on the plug optionally has a relatively shallow angle in comparison to the locking shoulder in the recess, and pushes the dogs radially outwards against the force of the spring as it enters the socket. The dogs move radially outwards over the shoulder, pivoting the lever arms, and then return under the force of the weak spring into the recess as the plug moves axially into its final engaged position. In the third configuration, the lever arms are not locked, and the dogs are free to move radially being biased only by the weak spring. The third configuration is optionally also the reset

configuration, which the socket will normally adopt automatically after any normal disconnect.

The connector assembly moves between the locked and unlocked configuration repeatedly, by movement of the piston axially with respect to the cylinder, in order to engage and disengage the key with the lever arms. When the connector assembly is in the locked configuration, with the hydraulic cylinder in the first position, and the key engaged to retain the dogs in the recess, the assembly can be disconnected under emergency conditions, optionally as a result of excess tension across the connector assembly. This may occur, for example as a result of drifting of the support vessel.

The emergency disconnect system comprises a selectively actuable support for the hydraulic cylinder operating the key, which is activated by the emergency disconnect in order to remove the support for the hydraulic cylinder and allow it to move axially in order to disengage the key from the lever arms, and allow them to move.

Optionally, the selectively actuable support comprises at least one support plate that is pivotally mounted on the second part and which in a first configuration supports the hydraulic cylinder in its first position, in which the key that is provided on the piston of the hydraulic cylinder can engage the lever arms to restrict the movement. In certain examples, the selectively actuable support comprises at least 2 plates, pivotally mounted on opposite sides of the cylinder, and arranged to move pivotally between the first configuration and a second configuration in which the plates move around the pivot connections to the second part such that the hydraulic cylinder is no longer supported, and is able to move axially. In the second configuration, the hydraulic cylinder can move axially away from the lever arms so that the key is no longer able to engage the lever arms, thereby freeing the dogs on the lever arms that are engaged within the recess on the plug. Optionally, the movement of the plate (s) supporting the hydraulic cylinder between the first and second configurations is guided by guide pins disposed within tracks on a trigger plate which is adapted to move axially in response to tension experienced across the connector assembly. Optionally, the trigger plate is connected to the trigger line attached to the flowline, so that excess tension on the trigger line moves the trigger plate axially with respect to the connector assembly. Optionally, the tracks on the trigger plate have axial and diverging legs, which can drive the movement of the pins connected to the plates, thereby driving the movement of the plates between the first and second configurations.

The emergency disconnect system activates when a threshold of tensile load is applied to the trigger plate to overcome the preload resilient devices (e.g. springs) biasing the trigger plate towards one end of the second part, compressing the springs. The 1^st stage of axial movement of the trigger plate optionally does not change the cylinder support plates which in the 1^st stage still fully engage the cylinder as the pins on the cylinder support plates are still in the initial axial portion of the track and have not diverged. At this point if the tension were released the trigger plate would be pushed back to its starting position by the springs.

The ED sequence is only triggered after the trigger plate is pulled beyond the 1^st stage, and the pins on the cylinder support plates have moved along the track into the diverging legs of the track, forcing the radial outward movement of the cylinder support plates. The cylinder is optionally at least partially disposed in a recess in the trigger plate and a face of the recess on the trigger plate is at that point pulled away from the hydraulic operating cylinder. At the same time a surface on the other end of the recess on the trigger plate has engaged the opposite end of the cylinder. A relatively weak cylinder spring is axially urging the cylinder into the first position at this point, so if tension is released at this 2^nd stage, the trigger plate returns to its starting position, the cylinder support plates swing back to support the cylinder, and this stage 1 configuration is resumed. When the trigger plate has been pulled beyond stage 2, the trigger plate pulls the hydraulic cylinder axially within a recess, which in turn moves the piston and key away from the lever arms, thereby releasing the dogs on the lever arms from the recess on the plug. The plug can then pull clear of the socket. As the plug and socket separate, the tension on the trigger plate is released and it is forced back to its home position by the springs. The hydraulic cylinder is hydraulically retracted to reset the connector assembly to the Unlocked - Reset configuration described above.

Optionally the emergency disconnect system can be hydraulically operated.

Optionally the flowline on each side of the connector assembly is flexible, but the connector assembly can be used in rigid flowlines, or to connect a flexible flowline to a rigid flowline. Optionally the hydraulic control lines in the connector assembly e.g. to move the piston can be connected to a port allowing hydraulic control signals to be issued by an ROV near to the stack.

Optionally the connector assembly can be made up by an ROV.

The various aspects of the present invention can be practiced alone or in

combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one aspect can optionally be combined alone or together with other features in different aspects of the invention. Any subject matter described in this specification can be combined with any other subject matter in the specification to form a novel combination.

Various aspects of the invention will now be described in detail with reference to the accompanying figures. Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the figures, which illustrates a number of exemplary aspects and implementations. Any subject matter described in the specification can be combined with any other subject matter in the specification to form a novel combination. The invention is also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including", "comprising", "having", "containing", or "involving" and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word "comprise" or variations thereof such as "comprises" or "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention.

In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting essentially of", "consisting", "selected from the group of consisting of, "including", or "is" preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words

"typically" or "optionally" or derivatives of the same are to be understood as being intended to indicate optional or non-essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention. All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa. References to directional and positional descriptions such as upper and lower and directions e.g. "up", "down" etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee.

Brief Description Of The Drawings

In the accompanying drawings:

Figures 1 & 2 show perspective views of a connector assembly;

Figure 3 shows a second part of the figure 1 connector assembly;

Figure 4 shows a top view of the figure 1 assembly in a locked configuration;

Figure 5 shows a section view through line E-E of figure 4;

Figure 6 shows a side view of the figure 1 assembly;

Figures 7 and 8 show section views through lines B-B and C-C in figures 4 and 6;

Figure 9 shows a top view of the figure 1 assembly in an unlocked and open configuration;

Figure 10 shows a section view through line F-F in figure 9;

Figure 11 shows a top view of the figure 1 assembly in an unlocked and closed configuration;

Figure 12 shows a section view through line G-G in figure 11;

Figure 13 shows a top view of the figure 1 assembly in stage 1 of an emergency disconnect configuration;

Figures 14 and 15 show section views through lines H-H and L-L in Figure 13;

Figure 16 shows a top view of the figure 1 assembly in stage 2 of an emergency disconnect configuration; Figures 17 and 18 show section views through lines I-I and M-M in figure 16;

Figure 19 shows a top view of the figure 1 assembly in stage 3 of an emergency disconnect configuration;

Figures 20 and 21 show section views through lines J-J and N-N of figure 19;

Figures 22-24 show a sequence of perspective views of the connector assembly in locked, unlocked and open and unlocked and closed configurations;

Figures 25-27 show a sequence of perspective views of the connector assembly in 1^st, 2^nd and 3^rd stages of emergency disconnection;

Figures 28-30 show sectional views of the same sequence of 1^st, 2^nd and 3^rd stages of emergency disconnection;

Fig 31 shows a schematic view of the fig one connector being used to connect two parts of a flowline;

Figures 32-36 show views of a modified version of the fig 1 connector, showing sequential steps of the modified connector in unlocked(fig 32), locked (Figs 33 and 34) and unlocked (figs 35-36) configurations; and

Figures 37-42 show views of a further modified version of the fig 1 connector, showing sequential steps of the modified connector in different configurations.

Detailed Description Of Examples Of The Invention

Referring now to the drawings, a connector assembly comprises a first part 5 incorporating a plug 6 at one distal end and a second part 20 incorporating a socket 21 at one distal end. The first part 5 has a bore 7 extending between opposite ends and aligned with the axis X-X of the connector assembly. The proximal end of the first part 5 opposite the distal end with the plug 6 is adapted to connect to a flowline F configured to supply a fluid to a subsea well W from the surface supply ship V.

The fluid supplied from the surface supply ship V is conveyed through the flowline F and through the first part 5 by means of the axial bore 7. In this example, the connector assembly connects fluid conduits, but in other examples the conduits could be of other types such as signal or power conduits or combinations of the same. The second part 20 likewise has an axial bore 28 extending axially from one end of the second part to the other. The end of the second part 20 opposite to the socket is adapted to connect to a fluid conduit subsea, and in most examples of the invention, the fluid conduit is connected to a well W, optionally to a wellhead stack S on the seabed, as shown in Fig 30.

The plug 6 is configured to engage within the socket 21 to make up the connector assembly 1. When the plug 6 is engaged within the socket 21, the flow path from the flowline is connected through the connector assembly 1, and the bores 7, 28 are aligned along the axis, and interconnect to complete the fluid conduit through the connector assembly 1.

Optionally, each of the bores 7, 28 incorporate a valve, optionally a check valve. In the present example, the bore 7 incorporates a valve 8, and the bore 28 incorporates a valve 23. Optionally, the valves 8, 23 are normally closed, and are biased into the closed position by means of a resilient device such as a spring, but may be hydraulically controlled. In the present example, control lines extend parallel to the flowline and optionally parallel to the fluid conduit connected to the second part 20 in order to provide hydraulic control signals for operation of the valves 8, 23. In the present example, both of the valves 8, 23 are normally closed by means of springs or other resilient devices, but are also provided with control lines to override the function of the spring and allow remote control of the valves. In the present example, each of the valves 8, 23 on opposite sides of the connector assembly 1 can be operated by control lines from either side of the connector assembly 1, and optionally, the connector assembly 1 incorporates shunts or similar fluid conduits (optionally passing axially through the plug 6, for example parallel to the central bore and spaced between the central bore 7 the corners of the plug 6, optionally closer to the corners than to the central bore 7) to transfer or transmit hydraulic control signals present in the control lines on either side from one side of the connector assembly 1 to the other. The shunts through the plug 6 optionally connect with mating control lines on either side of the plug 6 to continue the fluid circuit for the control lines through the connector 1. The socket 21 has four inner side walls 25 configured to engage with four outer side walls 10 of the plug 6 when the plug 6 is received in the socket 21. The inner walls 25 of the socket 21 and the outer walls 10 of the plug 6 have planar sections that present flat surfaces that inter-engage when the connector assembly is made up. The planar sections extend parallel to one another and to the axis of the connector assembly. In the present example, some planar sections are spaced apart from one another, but are on the same plane, for example, the planar sections on the plug 6 comprise guide surfaces 11, which extend axially along the plug 6 at the corner edges, optionally extending continuously between opposite ends on raised portions rising slightly above the plane of the faces 10. These guide surfaces 11 engage the inner walls 25 of the socket 21 and provide the planar sections on the plug 6. The guide surfaces 11 on adjacent faces 10 meet at the edges of the plug. Each face 10 of the plug 6 therefore has at least two planar guide surfaces 11 spaced apart from one another on opposite sides of the face, but in the same plane, and extending parallel to one another.

In the present example, the planar sections of the guide surfaces 11 are generally rectilinear, forming general rectangular shapes. Each of the plug 6 and the socket 21 has a generally rectilinear cross-section in the shape of a square.

The faces 10 of the plug 6 may optionally incorporate recesses 13, so the faces 10 themselves may not be completely flat, and may not be completely planar, although this is an option. Forming recesses 13 within the faces 10 is advantageous, because it reduces the weight of the connector assembly. While a single planar section on each face 10 would be sufficient, it is advantageous to space the planar sections on the guide surfaces 11 at opposite sides of each face 10, as this provides more stable alignment between the plug 6 and the socket 21 when interconnected. Optionally, each face incorporates a recess 15 extending across the flat face 10. The recess 15 is formed by ramps on either side of a base. The ramps are optionally disposed on opposite axial sides of the base, and optionally the ramp nearest to the free end of the plug 6 has a steeper angle than the other ramp. The recess 15 is adapted to receive a dog in order to restrain relative axial movement of the plug 6 and the socket 21 when interconnected. The recess 15 optionally has a consistent depth across the width of the flat face 10, and the ramp adjacent to the leading end forms a straight line apex between the outer face 10 of the plug and the recess 15.

The socket 21 has a cylindrical bore 27 at its inner end, in fluid communication with the bore 28 extending into the flowline. The cylindrical bore 27 optionally has a seal assembly on its inner surface, and is adapted to receive a cylindrical head 17 on the outer end of the plug 6 when the plug is received within the socket. The seal assembly on the inner surface of the cylindrical bore 27 seals the cylindrical head 17 within the cylindrical bore 27 when the plug is received within the socket.

The generally square bore 22 of the socket 21 receives the generally square plug 6, and the planar faces on the guide surfaces 11 on the plug engage with

corresponding planar faces on the corners of the square bore 22. The planar faces on the plug 6 or on the socket 21 can be faced with low friction materials in certain examples. The first and second parts 5, 20 are locked together by a restraining device 50 which is adapted to resist disconnection of the two parts when the connector is made up. In this example, the restraining device 50 comprises a dog 55 mounted on the inner surface of a lever arm 51 on opposite faces (e.g. top and bottom faces) of the second part 20. In the present example, the lever arms 51 are pivo tally connected to the second part at a pivot connection 51p on opposite flat faces of the second part 20. The pivot connection 51p connects one end of each lever arm 51 to an external surface of the socket, and the other end of each lever arm 51 is provided with a locking device configured to resist movement of the lever arm around the pivot link. When the lever arms 51 are locked together, the dog 55 extends through a window 30 through the flat face of the socket 21, and is locked into the recess 15 in the plug 6, thereby locking the restraining device in place and restricting or preventing disconnection of the first and second parts 5, 20. The locking device comprises a hydraulic cylinder 41 and a c-shaped key 40 fixed to the end of the piston 41p on the cylinder 41, so that the extension of the piston 41p moves the c-shaped key in a linear path, between an unlocked position in which the key is spaced apart from the lever arms 51, and a locked position in which the parallel limbs of the key 41 extend into slots cut in radial fingers 52 formed on the ends of the arms 51, thereby restricting relative movement of the lever arms 51. The same key 41 engages both of the lever arms 51, and thereby maintains the dogs 55 engaged in the recesses 15 when the connector assembly 1 is in the locked position. The piston 41p is extended and retracted by hydraulic control lines, which optionally extend from the surface to the subsea stack and from there to the socket 21. Optionally, the control lines can extend from the surface ship parallel to the flowline and can extend through the connector assembly. Pivotally mounting the lever arms 51 on a planar external face of the socket 21 on opposing faces of the socket creates a compact connector, and balances the forces applied.

The load-bearing shoulders provided by the ramp on the distal end of the recess 15 and the load face on the dog 55 are optionally both rectilinear, parallel, can be usefully set at the same angle and can usefully have the same shape. The apex between the free edges of the load faces and the pin outer wall is optionally flat and linear i.e. arranged on a straight line in a single plane, optionally parallel to and in the same plane as the outer wall 10 of the plug 6. Arranging the load-bearing shoulders of the dog and the recess in this way allows a faster disconnection between the plug 6 and the restraining mechanism 50, allowing a more

instantaneous release of the plug 6 from the socket 21. This helps to reduce the wear on the load shoulders during the transitions and helps to reduce shearing of the corners.

The connector assembly 1 incorporates an emergency disconnect system reactive to tension across the connector assembly, which disconnects the connection assembly above a tension threshold. The emergency disconnect system comprises a trigger line 65 connected between a trigger plate 62 on the assembly and a part of the flow line spaced apart from the connector assembly 1. Optionally, a pair of trigger plates 62 are mounted on opposing flat sides of the socket 21, and each trigger plate 62 is optionally biased in an axial direction towards the inner end of the socket 20 by a pair of springs 61 disposed one on either side of the trigger plate. The trigger line 65 (see fig 31) is shorter than the length of flow line between the connector assembly 1 and the trigger line connection to the flow line, so that when the trigger line 65 is tensioned beyond a threshold (below the load limit of the connector assembly 1) it pulls the trigger plate 62 to disconnect the two mating parts 5, 20 before the flow line is subjected to tension.

The connector assembly 1 has a locked configuration shown in Figs 4-8, when the first and second parts are engaged, and the locking device is locked. The hydraulic cylinder 41 driving the movement of the key 40 is housed in a recess 42 r in a first operating position and the piston 41p on the cylinder 41 is extended to engage the key 40 with the radial fingers 52 on the lever arms 51 and to retain the dogs 55 in the recesses 15 on the plug 6. The key 40 is constrained to move parallel to the axis, partly because the cylinder 41 is retained within the recess 42r which is parallel to the axis, but also because the key 40 has a central spline extending between the c- shaped outer limbs of the key 40 which engage the fingers 52 on the lever arms 51, which maintains the alignment of the key 40 with the axis during travel of the key 40, and ensures that the outer limbs of the key 40 accurately engage with the slots on the radial fingers 52. With the piston 41p fully axially extended in the locked configuration shown, for example in figure 5, the lever arms 51 are locked against radial outward movement by the key 40. Retraction of the piston 41p is necessary to disengage the limbs of the key 40 from the slots on the fingers 52 before the lever arms 51 can move radially outwards. In the locked position shown in figures 4 to 8, the dogs 55 and the second part 20 are firmly engaged within the recess 15 on the first part 5 (as best shown in figure 7), thereby preventing axial movement of the first and second parts 5, 20.

In a second configuration shown in figures 9 and 10, the connector assembly is unlocked, with the hydraulic cylinder 41 still in the first position, as in the locked configuration but the piston 41p is axially retracted within the cylinder 41 to pull the key 40 axially out of engagement with the lever arms 51. The lever arms 51 are biased radially inwards by a resilient device such as a relatively weak spring (not shown), so when the piston 41p retracts into the cylinder 41 to disengage the key 40, the plug 6 can be pulled out of the socket 21, urging the dogs 55 out of the recesses against the force of the spring. The weak spring can optionally be a leaf or beam spring mounted on the flat outer surface of the socket 21 between the lever arm diverging legs, and applying a spring force between the outer face of the socket and the lever arms to press the lever arms 51 radially inwards.

After the plug 6 is clear of the socket 21 the connector assembly 1 is in a third unlocked and reset configuration shown in Figs 11 and 12. The plug 6 has pushed the dogs 55 aside on the way out of the socket and the arms 51 have then been urged back radially inwards by the spring. This is the normal resting position of the socket 21, which it adopts when the plug 6 is disengaged from the socket 21. The leading end dog-engaging shoulder 6h on the plug 6 optionally has a relatively shallow angle in comparison to the inner shoulder on the dog 55, and pushes the dogs 55 radially outwards against the force of the weak spring as the plug 6 enters the socket 21. The dogs 55 move radially outwards over the shoulder 6h, and then return under the force of the weak spring into the recess 15 as the plug 6 moves axially into its final engaged position. In the third configuration, the lever arms 51 are not locked, and the dogs 55 are free to move radially being biased radially inwards only by the weak spring. The third configuration is optionally also the reset configuration, which the socket 21 will normally adopt automatically after any disconnect.

When the connector assembly 1 is in the locked configuration as shown in Figs 4-8, with the key 40 engaged with the fingers 52 to retain the dogs 55 in the recess 15 and lock the parts 5, 20 together, the assembly 1 can be disconnected under emergency conditions, for example, in response to excess tension across the connector assembly 1. The emergency disconnect system comprises a selectively actuable support for the hydraulic cylinder 41. The selectively actuable support comprises a pair of cylinder support plates 45 pivotally mounted on pivot pins 45p securing one end of the plates 45 to the socket 21, and which normally converge radially inwards at their free ends to support the hydraulic cylinder within the recess 42r in its first position, axially spaced from the inner end of the recess 42r. In this position, shown in Figs 4-8, the key 40 on the end of the piston 41p can move in and out of the cylinder 41 to engage the lever arm fingers 52 and restrict movement of the arms 51 and lock the dogs 55 in the recesses 15 in the plug 15, and then disengage to release them. The hydraulic cylinder support plates 45 are pivotally mounted on opposite sides of the cylinder 41, and are arranged to move pivotally around the pins 45p between the first configuration where the plates 45 are converging to engage the inner end of the hydraulic cylinder 41 and a second configuration in which the free ends of the plates 45 swing radially out to a parallel configuration, away from the hydraulic cylinder 41 so that the inner end of the hydraulic cylinder 41 is no longer supported, and the cylinder 41 is able to move axially within the recess 42r. The hydraulic cylinder 41 is biased within the recess 42r toward the inner end of the socket 21 by a spring 42s best seen in figure 12 held in compression within the recess 42r. Under moderate loads, the spring 42s within the recess 42r is sufficiently strong to maintain the cylinder 41 in the position shown in figures 4 to 8 even when the free ends of the hydraulic cylinder support plates 45 swing into the second configuration.

The movement of the hydraulic cylinder support plates 45 between the first and second configurations is guided by guide pins 46 captive within tracks 63 on each trigger plate 62. Each trigger plate 62 is adapted to move axially in response to excess tension on the trigger line, which pulls each trigger plate 62 axially with respect to the socket 21 towards the open end of the socket 21, as best shown in the progression of figures 25 to 27. The tracks 63 in the trigger plates 62 have axial portions at each end which are parallel and diverging portions between the axial portions. When the pins 46 move axially relative to the tracks 63 into the diverging portions, the free ends of the plates 45 start to swing between the first and second configurations. The emergency disconnect system activates when a threshold of tensile load is applied to the trigger plates 62 to overcome the force on the springs 61 biasing the trigger plates 62 towards the inner end of the socket 21. However, the system has several stages, not all of which necessarily result in activation of the emergency disconnect.

Initial overpull on the connector assembly 1 tensions the trigger line 65, compresses the springs 61 and moves the trigger plate 62 axially as shown in the progression of Figs 25-27 for example. If the axial range of movement of the trigger plate 62 is only slight, for example to the Fig 13-15 position, the free ends of the cylinder support plates 45 are still in the converging engaged position (as the pins 46 on the cylinder support plates 45 are still in the initial axial portion of the track 63 and have not diverged). At this stage 1, if the tension were released the trigger plate 62 would be pushed back to its starting position in Fig 5 by the force of the springs 61.

The emergency disconnect sequence is only triggered after the trigger plate 62 is pulled beyond the stage 1 threshold. In stage 2, the pins 46 on the cylinder support plates 45 have moved up the track 63 into the beginning of the diverging legs of the track as shown in Fig s 16-18. The cylinder is optionally at least partially disposed in a recess 62r in the trigger plate 62 (see Fig 28) and an axially outer face of the recess on the trigger plate 62 closest to the open end of the socket 21 is at that point separated from the cylinder 41. At the same time a surface on the axially inner end of the recess 62r in the trigger plate 62 has engaged the end of the cylinder 41, but has not started to move the cylinder towards the open end of the socket 21, as the cylinder support spring 42s is urging the cylinder 41 into the first position spaced away from the outer end of the recess 42r, so if tension is released the trigger plate would once return to its starting position shown in Fig 5.

When the trigger plate 62 has been pulled beyond the stage 2 point, the end of the socket 62r engages the hydraulic cylinder 41 and moves it axially within the recess 42r towards the open end of the socket 21, which in turn moves the piston 41 and key 40 axially away from the lever arm fingers 52, thereby releasing the dogs 55 on the lever arms 51 from the recess 15 on the plug 6. The plug 6 can then pull clear of the socket 21. As the plug 6 and socket 21 separate, the tension on the trigger plate 62 is released and it is forced back to its home position by the springs 61. The piston 41p on the hydraulic cylinder 41 is hydraulically retracted to reset the connector assembly to the Unlocked - Reset configuration described above.

Optionally the ED system can be hydraulically operated.

In use, the second part 20 with the socket 21 is optionally attached onto the distal end of a flowline F, and the first part 5 with the plug 6 forms an end termination on a second part of the foregoing leading to a subsea stack S serving a well W (see figure 31). The flowline F extending from a vessel V or from a platform above the well W is ballasted by a weight attached to the flowline, but a portion of the flowline between the ballast connection and the termination at the socket 21 hangs loosely in the water column. The check valve in each of the socket 21 and the plug 6 is optionally urged by a spring or by hydraulic pressure in a control line to close the bore before the connector is made up. The trigger line 65 is connected between the flowline F and the trigger plate 62, and has a shorter length than the section of the flowline that hangs loosely, as generally shown in figure 31.

Initially, the first and second parts 5, 20 are in the unlocked configuration shown in figures 11 and 12, with the cylinder support plates 45 swung in to support the hydraulic cylinder 41, and the piston 41p withdrawn within the cylinder to disengage the key 40 from the fingers 52 on the lever arms 51. The first part is grasped by an ROV using the ROV handles provided, and the plug 6 is advanced into the socket 21, which causes the shoulder 6h to engage the dogs 55 protruding into the socket 21 through the windows 30, thereby pushing the dogs 55 are radially outwards so that the lever arms 51 adopt the configuration generally shown in figure 10. Once the plug 6 is fully inserted into the socket 21, and the recesses 15 on the outer surface 10 of the plug 6 have come into alignment with the windows 30, the dogs 55 move radially inwards into the recesses 15. The connector assembly 1 is then ready to be locked by axial translation of the key 40 on the end of the piston 41p into the slots on the radial fingers 52 of the lever arms 51. Once that happens, the connector assembly is then in the configuration shown in figures 4 to 8.

Axial translation of the key 40 can be repeated in either direction under control of hydraulic lines feeding the cylinder 41 as many times as is necessary, in order to lock and unlock the connector as desired. Provided that the tension across the locked connector is insufficient to overcome the compression of the springs 61, the emergency disconnect system 60 remains inactive, and the free ends of the cylinder support plates 45 remain in the converging support position shown in figure 5, preventing axial translation of the cylinder 41, and maintaining the functionality of the lock 40 when activated by the hydraulic lines.

Referring now to figures 13 to 15, when the connector assembly 1 is in the locked configuration, and the tension across the connector assembly 1 is relatively small, the guide pins 46 within the slots 63 of the trigger plate 62 translate back and forward in the initial axial portion of the slot 63 as shown in figure 15, without disturbing the position of the cylinder support plates 45. If the tension increases beyond the stage 1 threshold, the trigger plate 62 may move slightly further, causing the pins 46 to begin to move up the divergent legs of the slot 63 as shown in figures 16 to 18. Provided that the tension remains below the stage 2 threshold, although the support plates 45 may swing to a more parallel configuration shown in figure 17, the force of the spring 42s held in compression between the recess 42r and the cylinder 41 maintains the cylinder 41 in the configuration shown in figures 16 to 18, thereby maintaining the key 40 in the locking configuration preventing dislocation of the connector assembly 1. When the tension is released, the support plates 45 swing back into the converging configuration shown in figures 13 to 15, to support the hydraulic cylinder 41 against axial movement.

If the stage 2 tension threshold is exceeded, the trigger plate 62 moves far enough to cause the pins 46 to track into the second axial portion at the end of the slot 63 as shown in figure 21, which swings the cylinder support plates 45 radially outwards into the parallel configuration. The tension threshold set for stage 3 is sufficient to overcome the combined force of the springs 61 and 42s. As shown in the sequence depicted in figures 28 to 30, the cylinder 41 is at least partially disposed within a recess 62r on the trigger plate 62, and once the end of the recess engages with the outer end of the cylinder 41, as shown in figure 29, any further movement of the trigger plate 62 towards the open end of the socket 21 drags the whole of the cylinder 41 away from the inner end of the socket 21, and away from the fingers 52 on the lever arms 51. Eventually, the axial translation of the trigger plates 62 reaches the figure 30 configuration, where the cylinder 41 has been dragged all the way forward towards the open end of the socket 21, compressing the spring 42 s within the recess 42r, and pulling the key 40 at the other end of the piston 41p out of engagement with the fingers 52 on the ends of the lever arms 51. Thus, the lever arms 51 are then free to swing around the pivot connections with the socket 21, and release the dogs 55 from the recesses 15, allowing disconnection of the two parts of the connector assembly 1.

Referring now to figs 32-36, a modification of the connector assembly 101 is shown in which like parts are numbered in a similar manner but increased by 100. The modified assembly 101 comprises a first part 105 incorporating a plug and a second part 120 incorporating a socket as previously described. The similar parts will not be described in detail again for brevity, but the reader is referred to the earlier parts of the description of the first example of the assembly for more details.

The connector 101 is mounted with the second part 120 on one side of a face plate P that is generally on the outer surface (or otherwise on an accessible surface) of a subsea structure such as a tree, manifold, etc., and the second part is often located within the structure. The outer surface of the face plate has an access port that is accessible to an ROV. The access port optionally has grab handles H to facilitate attachment of the ROV by an ROV manipulator. The restraining device 150 is substantially the same as the restraining device 50, but is locked by a different locking device in the form of a c-shaped key 140. The key 140 is mechanically actuated and is fixed to one end of a reciprocating rod 141 that is connected at its other end to a cam plate that is pivotally connected to the structure. The cam plate has a handle that extends through the access port, and can be accessed by an ROV manipulator. Moving the handle moves the cam plate around a pivot pin that is eccentrically mounted on the cam plate, and which translates the eccentric rotational movement of the cam plate around the pivot pin into linear translation of the reciprocating rod so that the linear movement of the reciprocating rod moves the c-shaped key in a linear path, between an unlocked position (shown in Figs 32, 35 and 36)in which the key 140 is spaced apart from the lever arms 151, and a locked position (shown in Figs 33 and 34) in which the parallel limbs of the key 140 extend axially into slots cut in radial fingers formed on the ends of the arms 151, thereby restricting relative pivotal movement of the lever arms 151 in the same way as previously described for the initial example. The same key 140 engages both of the lever arms 151, and thereby maintains the dogs engaged in the recesses on the plug when the connector assembly 101 is in the locked position, as described for the initial example. The key 140 is optionally constrained to move in a path that is parallel to the axis (optionally defined by a spline on the key that is received in a slot on the second part 120). Axial retraction of the key 140 to disengage the limbs of the key 140 from the slots on the fingers before the lever arms 151 can move radially outwards is a reversal of the rotational movement of the handle.

Optionally, the connector can be made up by the ROV, which optionally grasps an outboard handle on the first part 105, and introduces the plug into the socket by means of a manipulator arm on the ROV. This optionally results in the movement of the lever arms 151 as described in the first example, and the dogs on the lever arms 151 optionally click back into a recess on the plug in order to make up the connection, and tentatively hold the plug within the socket. The ROV can then release the handle on the plug, and use the same manipulator to operate the handle on the cam plate, in order to operate the key 140, and lock the two parts together. The access port can be in a vertical or horizontal surface, or in another orientation, and the connector assembly 101 can be made up when the parts are in different orientations. Referring now to figs 37-41, a further modification of the connector assembly 201 is shown in which like parts are numbered in a similar manner but increased by 200. The modified assembly 201 comprises a first part 205 incorporating a plug 206 and a second part 220 incorporating a socket as previously described. The similar parts will not be described in detail again for brevity, but the reader is referred to the earlier parts of the description of the first and second examples of the assembly for more details.

The connector assembly 201 differs from the earlier examples in that the two parts 205 and 220 need not connect a conduit within an internal bore of the parts 205, 220. Optionally, in this example, the conduits connected by the connector assembly 201 are external to the plug 206 and socket, and can optionally comprise fluid conduits 207, 228 which interconnect on the outer surfaces of the plug and socket. The conduits 207 and 228 are typically fluid conduits, optionally in the form of hoses, but the connector assembly 201 can optionally connect other types of conduit. For example, the conduits 207 and 228 can optionally comprise fluid, signal or power conduits or combinations of the same.

The restraining device 250 is substantially the same as the restraining device 50. The connector assembly 201 has a force transfer assembly in the form of a collet assembly 240 that is adapted to transmit forces between the two parts 205, 220, during disconnect procedures. The collet assembly 240 comprises a pair of pull pins 241 on the first part 205, which have heads that are received within collet fingers 245. The collet fingers 245 are restrained within the bore of a piston sleeve 242 that slides axially within a housing 243 between an "up" position shown in fig 42 where the piston sleeve 242 restricts the expansion of the collet fingers 245 and a "down" position shown in fig 41, in which the piston sleeve 242 has slid down the collet fingers 245 and uncovers a recess 244 that allows radial expansion of the collet fingers 245 into the recess 244, which allows axial movement of the head of the pull pins 241 in and out of the collet fingers 245. When the sleeve is "down" the recess 244 is uncovered by the sleeve 242, and the head of a pull pin 241 can click into the collet fingers, which can move radially out into the recess 244, to receive the head of the pin 241 and can then click back under their own resilience when the head of the pin 241 is engaged in the collet fingers 245 to retain the head against moderate pull-out forces which are overcome by the natural resistance of the collet fingers 245. When the piston sleeve 242 is "up" the collet fingers cannot radially expand, and the pin head is held tight by the collet fingers 245 within the housing 243, preventing relative axial movement of the pin and the collet fingers 245. The axial sliding of the piston from the down to the up position after the pin head is received by the collet fingers 245 locks the pins 241 into the collet assembly.

Thus when the connector parts are made up and the plug on the first part 205 is offered to the socket on the second part 220, the pull pins 241 on the first part 205 move into the housing 243 and the heads of the pins 241 are received by the collet fingers 245 which move radially out into the recess 244, which is uncovered because the piston sleeve 242 is "down". At the same time as the pins 241 are received in the collet fingers 245, the recesses on the plug 206 engage the dogs on the female portion. This is the configuration shown in Figs 37, 38 and 41. The radial resilience of the collet fingers 24 keeps a gentle force on the heads of the pull pins 241 and retains the connection at low forces. In addition the dogs are optionally resiliently biased into the recesses to hold the connector assembly in the coupled but unlocked configuration before locking. When the connector is to be locked in the closed position, a hydraulic circuit is operated (this can optionally be the same hydraulic circuit that operates the piston 41p in the first example) which moves the piston sleeve 242 from the "down" position shown in Fig 41 to the "up" position shown in fig 42. This covers the recess 244 within the housing 243, prevents radial outward movement of the collet fingers 245, and maintains the heads of the pull pins 241 locked in the collet assemblies 240. The twin dogs are kept locked in the recesses on the outer surface of the plug 206 by the same hydraulic force acting on the key 40, 140 etc, according to one possibility of this example. The connector can be unlocked by reversing the procedure.

The collet assemblies 240 are connected to the chassis of the second portion 220 by tie rods 265, which connect to a trigger plate 262 biased by springs 261 essentially as previously described for the trigger plate 262. The collet fingers 245 provide a mechanical connection between the pull pins 241 and the rods 265 such that tension from the first part 205 transferred to the pull pins 241 is transferred through to the rods 265 and the trigger plate 262. The plug 206 has an internal spring within a bore as best shown in Fig 40, which resiliently connects the shaft of a shackle on the plug 206 with the plug housing. The pull pins 241 are mounted on the shaft of the shackle, and the plug 206 allows relative movement of the pull pins 241 and the main body of the plug 206. This allows the pull pins 241 to be pulled back while the main body of the plug 206 is still held by the twin dogs. After sufficient pull on the pull pins 241 the trigger plate 262 will unlock the male mandrel 206 from the socket and any further movement will bring the collet head to the upper recess and so allow the pull pins 241 to pull free from the collets 245. In the event of high pull out forces, sufficient to cause an emergency disconnect of the connector assembly 201, the heads of the pins 241 transmit axial force to the tie rods 265 which pull the trigger plate 262 towards the first portion 205, and cause the twin dogs to unlock from the recesses on the outer surface of the plug 206 in a similar manner to the first example.

The different examples described herein can be combined such that the features used in each example can be used in the other examples in any combination.

Claims

1. A flow line connector assembly having first and second parts, the first part having a mating portion comprising a plug and the second part having a mating portion comprising a socket configured to receive the plug, the assembly having a restraining device to resist disconnection of the first and second parts when the plug is received in the socket, wherein the socket and plug have respective conduits being configured to interconnect between the first and second parts when the plug is received in the socket, wherein the socket comprises at least one inner wall configured to engage with at least one outer wall of the plug when the plug is received in the socket, and wherein each of the inner wall of the socket and the outer wall of the plug comprises at least one planar section.

2. A flow line connector assembly as claimed in claim 1, wherein the socket and plug have respective bores adapted to connect to make up a conduit for fluid to flow between the first and second parts when the plug is received within the socket.

3. A flow line connector assembly as claimed in claim 1 or claim 2, wherein the inner wall of the socket and the outer wall of the plug are side walls, and the planar sections extend parallel to the side walls and parallel to the axis of the connector assembly.

4. A flow line connector assembly as claimed in any one of claims 1-3, wherein the planar sections on the plug are parallel to the planar sections of the socket.

5. A flow line connector assembly as claimed in any one of claims 1-4, wherein the first and second parts comprise end terminations of a subsea flow line and wherein the connector assembly is configured to be used to connect a surface supply of fluid to a subsea location.

A flow line connector assembly as claimed in any one of claims 1-7, wherein at least one planar section is flat.

A flow line connector assembly as claimed in any one of claims 1-8, wherein at least one planar section is polygonal.

A flow line connector assembly as claimed in any one of claims 1-7, wherein the inner wall of the socket and the outer wall of the plug each comprise at least two planar sections.

A flow line connector assembly as claimed in claim 8, wherein on each of the plug and the socket, the planar sections are arranged in sets of two planar sections on each of the plug and the socket arranged on opposing and parallel sides of the plug and the socket.

A flow line connector assembly as claimed in any one of claims 1-9, wherein each of the plug and the socket can have a generally rectilinear cross-section.

A flow line connector assembly as claimed in any one of claims 1-10, wherein the plug and the socket each have an axis, and the planar faces are parallel to the axis.

A flow line connector assembly as claimed in any one of claims 1-11, wherein the planar faces converge at edges of the plug and the socket, wherein the edges are straight and parallel to the axis of the socket and the plug.

13. A flow line connector assembly as claimed in any one of claims 1-12, wherein the plug and the socket engage one another via guide surfaces, which extend axially along the connector assembly between opposite ends.

14. A flow line connector assembly as claimed in claim 13, wherein the planar faces are disposed on the guide surfaces.

15. A flow line connector assembly as claimed in claim 13 or 14, wherein the guide surfaces are formed adjacent to the edges between adjacent planar sections.

16. A flow line connector assembly as claimed in any one of claims 1-15, wherein the restraining device comprises a recess on one of the socket and the plug, and a dog on the other, wherein the dog engages within the recess in order to resist relative axial movement of the plug and the socket when the restraining device is engaged.

17. A flow line connector assembly as claimed in claim 16, wherein the recess is provided on a planar face on a wall of the plug or the socket.

18. A flow line connector assembly as claimed in claim 16 or claim 17, wherein the recess is non-symmetrical about a long axis of the connector assembly.

19. A flow line connector assembly as claimed in any one of claims 16-18, wherein the recess comprises a shoulder disposed at each end of the recess, wherein the shoulder nearest the free end of the first or second part is disposed at a steeper angle to the axis than the other shoulder.

20. A flow line connector assembly as claimed in claim 19, wherein at least one of the shoulders has an apex formed between the external wall of the plug and the recess, and the apex is planar in at least one plane, and wherein the dog has an apex set at the same angle as the shoulder of the recess, and wherein the apex of the dog is planar in at least one plane.

21. A flow line connector assembly as claimed in claim 20, wherein at least one face on the dog is planar and rectilinear, and at least one face on the dog engages with at least one face on the shoulder.

22. A flow line connector assembly as claimed in claim 20 or claim 21, wherein the apexes form a straight line, perpendicular to the axis of the connector assembly, and parallel to one another.

23. A flow line connector assembly as claimed in any one of claims 16-22, wherein the recess comprises a planar and rectilinear shoulder which engages a planar and rectilinear face on the dog, and wherein the inter- engaging faces on the recess and the dog are arranged at the same angle.

24. A flow line connector assembly as claimed in any one of claims 16-23, wherein the face on the recess which engages with the face in the dog is provided at the end of the recess nearest to the free end of the plug.

25. A flow line connector assembly as claimed in any one of claims 16-24, wherein the assembly includes a locking device adapted to lock the dog into the recess, thereby locking the restraining device in place and restricting or preventing disconnection of the first and second parts.

26. A flow line connector assembly as claimed in claim 25, wherein the connector assembly has a locked configuration, when the first and second parts are engaged, and the locking device is locked.

27. A flow line connector assembly as claimed in claim 25 or claim 26, wherein the dog is provided on a lever arm, having a pivot link connecting the lever arm to one of the first and second parts, and the other end of the lever arm is provided with a locking device configured to resist movement of the lever arm around the pivot link, wherein the locking device comprises a key that is actuated between an unlocked position in which the key allows free movement of the lever arm, and a locked position in which the key restricts movement of the lever arm, thereby restraining movement of the dog relative to the socket.

A flow line connector assembly as claimed in claim 27, wherein the locked configuration is enabled by a hydraulic cylinder moving the key in a linear path to engage the key with the lever arm and to retain the dog in the recess.

A flow line connector assembly as claimed in claim 28, wherein the connector assembly has an unlocked configuration, in which the hydraulic cylinder moves the key in a linear path out of engagement with the lever arm.

30. A flow line connector assembly as claimed in claim 29, wherein the connector assembly moves between the locked and unlocked configuration repeatedly, by movement of the key with respect to the lever arm by the cylinder.

31. A flow line connector assembly as claimed in any one of claims 27-30, wherein at least one lever arm is pivotally connected to a planar external face of one of the plug and the socket.

32. A flow line connector assembly as claimed in any one of claims 27-31, wherein two lever arms are provided and the external surfaces of the socket to which the lever arms are pivotally connected comprise at least two planar surfaces disposed on opposing sides of the socket, arranged in a generally rectilinear configuration; and wherein the locking device comprises a key that is actuated between an unlocked position in which the key allows free movement of the lever arms, and a locked position in which the key restricts movement of the lever arms, thereby restraining relative movement of the dogs on the lever arms in relation to one another.

33. A flow line connector assembly as claimed in any one of claims 27-32, wherein the restraining device is pivotally connected to the plug on opposing and parallel faces on the external surface of the plug, and the locking device is disposed on opposing and parallel faces on the external surface of the plug that are perpendicular to the faces with the pivotal connection to the restraining device.

34. A flow line connector assembly as claimed in any one of claims 27-33, wherein the lever arms are biased inwards by a resilient device so that in an unlocked configuration, the dogs remain within the recesses under the force of the resilient device, and wherein the resilience of the resilient device is sufficiently weak to be overcome when the plug is pulled out of the socket, thus pushing the dogs out of the recesses against the force of the resilient device.

35. A flow line connector assembly as claimed in claim 34, wherein after the plug is clear of the socket the connector assembly is in a third unlocked and reset configuration, wherein the socket adopts a resting positing where the dogs are urged radially inwards by the resilient device.

36. A flow line connector assembly as claimed in claim 34 or claim 35, wherein the leading end dog-engaging shoulder on the plug has a shallower angle than the locking shoulder in the recess, and pushes the dogs radially outwards against the force of the resilient device as the plug enters the socket.

37. A flow line connector assembly as claimed in any one of claims 26-36, wherein when the connector assembly is in the locked configuration, and the key engaged to retain the dogs in the recess, the assembly can be disconnected under emergency conditions as a result of excess tension across the connector assembly.

38. A flow line connector assembly as claimed in claim 37, including an emergency disconnect system comprising a selectively actuable support for the hydraulic cylinder moving the key, wherein the selectively actuable support is adapted to be actuated between different states in order to remove the support for the hydraulic cylinder and allow the cylinder to move in order to disengage the key from the lever arms, and allow them to disengage the dog from the recess.

A flow line connector assembly as claimed in claim 38, wherein the selectively actuable support comprises at least 2 plates, pivotally mounted on opposite sides of the cylinder, and arranged to move pivotally between the first configuration and a second configuration in which the plates move around the pivot connections to the second part such that the hydraulic cylinder is no longer supported, and is able to move.

A flow line connector assembly as claimed in claim 39, wherein in the second configuration, the hydraulic cylinder moves axially away from a locking formation on the lever arms so that the key is no longer able to engage the lever arms, thereby freeing the dogs on the lever arms that are engaged within the recess on the plug.

A flow line connector assembly as claimed in any one of claims 37-40, wherein the disconnect system comprises a trigger line connected between a trigger mechanism on the assembly and a part of the flow line spaced apart from the connector assembly.

A flow line connector assembly as claimed in claim 41, wherein the trigger line is shorter than the length of flow line between the connector assembly and the trigger line connection to the flow line, whereby the trigger line is tensioned and activates the disconnect system on the connector assembly before the flow line between the connector assembly and the trigger line is subjected to excessive tension.

43. A flow line connector assembly as claimed in claim 41 or claim 42, wherein the assembly comprises guide pins disposed within tracks on a trigger plate, the trigger plate being adapted to move axially in response to tension experienced across the connector assembly; and wherein the guide pins act to guide movement of the at least one plate supporting the hydraulic cylinder between the first and second configurations.

44. A flow line connector assembly as claimed in claim 43, wherein the trigger plate is connected to the trigger line attached to the flowline, so that excess tension on the trigger line communicated from the flowline is able to move the trigger plate axially with respect to the connector assembly.

45. A flow line connector assembly as claimed in claim 43 or claim 44, wherein the tracks on the trigger plate have axial and diverging legs, which drive the movement of the pins connected to the plates, thereby driving the movement of the plates between the first and second configurations.

46. A flow line connector assembly as claimed in claim 45, wherein movement of the pins within the axial legs of the trigger plate does not trigger change of the support plates which remain fully engaged with the cylinder as the pins on the cylinder support plates are in the axial leg of the track.

47. A flow line connector assembly as claimed in claim 45 or 46, wherein the emergency disconnect sequence is only triggered after the pins on the cylinder support plates have moved along the track into the diverging legs of the track, driving radial outward movement of the cylinder support plates.

48. A flow line connector assembly as claimed in any one of claims 43-47, wherein the emergency disconnect system activates when a threshold of tensile load is applied to the trigger plate to overcome the preloaded resilient devices biasing the trigger plate towards one end of the second part of the connector assembly, compressing the resilient devices.

49. A flow line connector assembly as claimed in any one of claims 43-48, wherein the hydraulic cylinder is at least partially disposed in a recess in the trigger plate and a face of the recess on the trigger plate is pulled away from the hydraulic operating cylinder at the same time as a surface on the other end of the recess on the trigger plate has engaged the opposite end of the cylinder.

50. A flow line connector assembly as claimed in claim 49, wherein a resilient device urges the hydraulic cylinder into a configuration in which the locking device maintains the restraining device in a locked configuration, and prevents disconnection of the assembly, and wherein if tension is released from the trigger plate while the restraining device is in the locked configuration, the trigger plate returns to its starting position, the cylinder support plates swing back to support the cylinder, and the assembly returns to the first configuration.

51. A flow line connector as claimed in any one of claims 43-50, wherein when the trigger plate has been pulled beyond stage 2, the trigger plate pulls the hydraulic cylinder axially within a recess, which moves the piston and key away from the lever arms, thereby releasing the dogs on the lever arms from the recess on the plug.

52. A flow line connector assembly as claimed in any one of claims 1-53, wherein more than one conduit is provided on a single assembly.

53. A flow line connector assembly as claimed in any one of claims 1-54, wherein each of the first and second parts incorporates a valve acting to seal the conduit.

54. A flow line connector assembly as claimed in claim 53, wherein the valve system includes a control line that can be actuated to change the activation state of the valve from one or both of the surface and the well.

55. A flow line connector assembly as claimed in claim 55, wherein the control lines are hydraulic control lines.

56. A flow line connector assembly as claimed in any one of claims 1-55, wherein the planar faces incorporate low friction materials.

57. A flow line connector assembly as claimed in any one of claims 1-56 wherein the conduits are internal to the plug and socket.

58. A flow line connector assembly as claimed in any one of claims 1-56 wherein the conduits are external to the plug and socket.

59. A flow line connector assembly as claimed in any one of claims 1-56 wherein the conduits are internal to the plug and socket.

60. A flow line connector assembly as claimed in any one of claims 1-59, wherein the restraining device comprises a collet assembly.