The present invention relates to a fluid coupling and a method of forming a fluid coupling.

Fluid couplings are known. In high pressure applications such as the oil and gas industry, pipelines carrying fluid under high pressure are required to be joined and separated under pressure and without spilling significant fluid. WO2008/087457 discloses an automatic solution whereby male and female coupling members are joined to form a fluid passageway. Exits of the fluid passageways on a probe and socket of each member are opened and closed by a sleeve and piston that slide relative to the probe and socket respectively. The coupling includes two cages that pivot to selectively clamp and de-clamp the sleeve to the socket and the probe to the piston to carry the separation forces when the coupling is transitioning between a balanced decoupled and fully closed state and a balanced coupled and fully open state. The cages are caused to selectively clamp and de-clamp the respective parts by movement of the probe and socket in a coupling axis

Consequently WO2008/087457 discloses a coupling that is arranged in a broken state, whereby fluid is retained in the respective fluid passageways of the male and female members by the sleeve and piston and such that the fluid pressure in the members is balanced. As the coupling is made by moving the probe into the socket in the coupling direction, the piston and probe abut to automatically open the fluid passageways. During insertion of the probe and socket by relative movement in the coupling direction, the cages are also caused to pivot closed to clamp the respective parts in order to carry the separation forces. One of the cages is arranged to lock the piston and probe together to act as a single part as the fluid passageway is opened and closed. Acting as a single part means the separation forces acting to force the piston and probe apart are carried by the cage and not therefore seen by the coupling. Likewise the second cage selectively locks the sleeve and socket together to carry the separation forces as the passageways move from the balanced fully closed state to the balanced, fully opened state.

The solution in WO2008/087457 therefore allows high pressure fluid pipe lines to be made and broken under pressure, automatically and without generating huge separation forces, which can be dangerous or make mating the coupling under pressure impossible without exerting vary large closing forces in the coupling direction. The pipelines are automatically opened and closed to prevent contamination of the surrounding environment and also, for instance, in undersea applications to prevent seawater from contaminating the pipeline which can cause corrosion to the seals and hydraulics. However, whilst the solution in WO2008/087457 works well for large diameter pipelines, for instance over 0.0254m in diameter, as the diameters are scaled down, the tolerances get too tight and the coupling loses its robustness so that impacts from general use are sufficient to alter the tolerances and prevent or jam the coupling from opening / closing

It is therefore an aim of the present invention to provide an improved coupling that overcomes the above or other disadvantage. It is a further aim to provide a coupling that provides an automatic opening and closing of the fluid passageways in each member on coupling and de-coupling that is able to be manufactured to small and large diameter fluid pipelines.

In embodiments according to the invention, first and second pairs of cooperating features are provided. The first pair of cooperating features are provided to lock a sleeve opening and closing a probe to a socket to prevent relative movement in a first axis and the second pair of cooperating features lock a piston opening and closing the socket to the probe to prevent relative movement in the first axis. The first and second pairs of cooperating features are arranged to be mated by relative movement in a second axis, wherein the second axis is angled to the first. Separation forces generated during coupling and decoupling are created in the first axis and are carried by the first and second pairs of cooperating features preventing relative movement of the socket and sleeve and the probe and piston. Advantageously, by arranging the first and second pairs of cooperating features to lock the parts by relative movement in an axis angled to the axis of relative movement the fluid coupling can be simplified allowing easier scaling whilst still providing a balanced coupling procedure that automatically opens and closes the fluid passageways.

In the exemplary embodiments, the relative movement in the first and second angled axis is linear movement such as a relative sliding movement.

The second axis is angled to the first axis in both a parallel direction and a direction perpendicular to the parallel direction. For instance, the second axis may be angled to the first axis between 1 o and 89o. At 1 o, the coupling acts closer to a piston and thus the forces required to make the coupling under pressure can become too high. At 89o, the coupling becomes excessively long. In the exemplary embodiments the angle is preferably 30° and suitably in a range of between 25°-35°, but the angle may suitably be between 30°-45° or 20°- 30°. In practice, 25° - 45° would be the typical limit.

According to the exemplary embodiments, there is provided a fluid coupling comprising a male coupling member and a female coupling member. The male coupling member has a fluid passageway that exits on an outer face of a probe. The female member has a fluid passageway that exits on an inner face of a socket. A sleeve is provided on the male coupling member to move relative to the probe in a first axis. The sleeve is moveable between an open and closed position. In the open position, the sleeve does not prevent fluid egress from the exit of the passageway. In the closed position, the sleeve seals the exit to the passageway. First sealing means are provided to seal between the probe and socket on either side of the fluid passageway when the sleeve is in the closed position. A piston is provided on the female coupling member. The piston is moveable relative to the socket in the first axis and between an open and closed position. In the open position, the piston does not prevent fluid egress from the exit of the passageway. In the closed position, the piston seals the exit to the passageway. Second sealing means seal between the piston and socket on either side of the fluid passageway when the piston is in the closed position. The male and female members are coupled by relative movement in a second axis. The second axis is angled to the first axis. The sleeve of the male coupling member and the socket of the female coupling member include a first pair of cooperating features formed in the second axis. Likewise, the probe of the male member and the piston of the female member comprise a second pair of cooperating features formed in the second axis. The first and second pairs of cooperating features are formed so as to be mated and un-mated by relative movement in the second axis.

Consequently, there is provided a method of coupling the male and female members. The method comprises moving the male and female members with respect to each other in the second axis. Herein the second axis is termed the coupling direction. Relative movement in the coupling direction towards each other mates the first and second cooperating features. When mated, the first pair of cooperating features prevents relative movement of the sleeve and socket in the first axis. Likewise, when mated, the second pair of cooperating features prevents relative movement of the probe and piston in the first axis. The probe is then moved relative to the sleeve in the first axis to open and close the fluid passageways in the male member. Because the probe and piston are locked together in the first axis, the piston is also caused to move in the first axis to thereby open the fluid passageway in the female member. The first axis is termed herein the actuating axis. During transition from the un-coupled and balanced fully closed arrangements and the coupled and balanced fully open arrangements separation forces are generated between the probe and piston and sleeve and socket due to the fluid pressure. The separation forces act in the actuating axis. It will therefore be appreciated that the separation forces are carried by abutment of the first and second pairs of cooperating features that abut to prevent relative movement of the parts in the actuating direction.

In the exemplary embodiments, a vent is provided to vent the first pair of cooperating members in order to prevent a piston affect restricting engagement of the cooperating features. Here, the first pair of cooperating members includes a third sealing means and the vent is arranged to be closed when the first pair of cooperating members are cooperatively arranged in use. The vent may be opened by pressure. That is, the vent may be biased closed, but when pressure created by the piston effect of the first pair of cooperating features builds, the pressure overcomes the biasing force to open the vent. In the exemplary embodiments an improved vent is provided. Here, the vent has a closing member supported in a body. The body is arranged to house the closing member. The body is contained in one of the coupling parts. The other of the coupling parts includes an open vent channel, which allows fluid to vent the coupling when the coupling is mated to alleviate any piston forces. When the parts are mated, the closing member is biased to a position to close the vent channel. The body includes a fluid passageway from a front of the body to a rear of the closing member. Consequently, when the coupling is mated and the vent closed, fluid in the system is caused to flow into the fluid passageway to behind the closing member. The seal is therefore improved as fluid pressure in the pipeline is increased as the fluid pressure acts to force the closing member into contact with the vent of the other member.

There is therefore provided according to a further aspect a vent comprising a body housing a closing member. The vent has a front face and the closing member protrudes from the front face. The closing member is moveable towards and away from the front face. The body includes a fluid passageway connecting the front face to a space behind the closing member. In the exemplary embodiments, the closing member is a ball. Here, the ball is housed in a cylindrical bore of the body. Suitably, the body is also generally cylindrical. The body may include an external thread to be connected to a closing member. The fluid passageway may preferably be a flat section formed in the thread. Here, the flat section may be formed in the axial direction of the body. An aperture may be formed between the flat section and the rear space. The aperture may preferably be formed perpendicular to the axial direction.

In the exemplary embodiments, the second pair of cooperating members includes a fourth sealing means. Advantageously, the fourth sealing means reduces the effective area of the coupling creating the separation forces. Consequently the separation forces that the cooperating features must carry are reduced. The second pair of cooperating members are vented to prevent a piston affect restricting engagement of the cooperating features. The vent may be opened on forming the seal between the second pair of cooperating features. Alternatively, the vent may be a simple open fluid channel to the environment as the space does not see fluid in use. It will be appreciated that the vent may also be substantially as herein described in relation to the vent associated with the first pair of cooperating members.

In one exemplary embodiment, multiple probes and sockets are formed so as to simultaneously mate and un-mate multiple fluid pipelines. Here, the sockets of each adjacent pipeline may be formed in an integral part. Each socket includes an independent piston to open and close the socket. The pistons of adjacent pipelines may be formed as a single piece so as to act as a single unit thereby allowing a single action, for instance a Remotely Operated Vehicle (ROV), to mate the multiple couplings in a single movement. The sleeves may be independently mounted or may be a single piece.

In one exemplary embodiment, the coupling is provided with a breakout mechanism. Breakout mechanisms are used to tie the coupling together to carry external loads. Typically the breakout mechanism is designed to fracture and break apart when a predetermined axial load is applied. Thus, if an unexpected external tensile force is applied to the coupling, the breakout mechanism is arranged to separate and allow the coupling to be pulled apart. In the exemplary embodiments, the breakout mechanism is a tension pin that couples the piston and socket. According to the exemplary embodiments, there is provided a fluid coupling capable of automatically opening and closing a fluid pipeline even when the pipeline is pressurised, wherein the fluid coupling has a simple and robust mechanism that is able to be scaled to small diameter pipelines . For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figures 1 a-c are partial cross-sectional perspective views of a fluid coupling according to an exemplary embodiment in a separated, coupled and activated arrangements;

Figure 2 is a perspective view of the fluid coupling in a separated arrangement.

Figures 3 and 4 show a cross-sectional view and a perspective view of the fluid coupling of Figure 1 in a coupled but closed arrangement;

Figures 5 and 6 show a cross-sectional view and a perspective view of the fluid coupling of Figure 1 in a coupled and actuated arrangement; Figure 7 is a perspective view of a fluid coupling according to a further exemplary embodiment;

Figure 8 is a perspective view of a fluid coupling according to a further exemplary embodiment; Figures 9 and 10 are partial cutaway views of the fluid coupling of Figure 8 showing the coupling in various stages of the mating process; Figures 1 1 and 12 show cross-sectional views of an area of the fluid coupling of claim 8 in part mated and fully mated positions; and

Figure 13 shows a perspective view of an exemplary vent for use in a fluid coupling. Referring to Figures 1 and 2 a fluid coupling 100 is shown. The fluid coupling has a male coupling member 1 10 and a female coupling member 120. The male coupling member has a fluid passageway 1 1 1 that extends from a distal end 1 12 connected to a pipeline and a circumferential face 1 13 of a probe 1 14. The female coupling member has a fluid passageway 121 that extends from a distal end 122 connected to a pipeline and a circumferential face 123 of a socket 124. The socket 124 is sized so as to receive the probe 1 14. The probe is closed by a sleeve 1 16. The sleeve 1 16 is mounted to the probe 1 14 so as to be able to slide between a closed position, wherein the sleeve closes fluid passageway on the circumferential face 1 13, and an open position wherein the fluid passageway is open. First ealing means 1 17, 1 18 are arranged either side of the fluid passageway in the circumferential face 1 13 when the sleeve is in the closed position. The socket is closed by a piston 126. The piston 126 is mounted to the socket so as to be able to slide between a closed position and an open position. In the closed position, the piston closes the fluid passageway in the circumferential face 123. Second sealing means 127, 128 are arranged either side of the fluid passageway in the circumferential face of the socket when the piston is in the closed position.

The male and female coupling members are mated by relative movement in a first, coupling axis A. As shown in Figures 3 and 4, once mated, the probe 1 14 and piston 126 become aligned. Being co-axial, the fluid coupling can be opened by relative movement of the probe and piston in a second, actuating axis B. Here, the probe can be slid relative to the sleeve to project into the socket. Said movement causes the piston to slide relative to the socket. It will be appreciated that the sleeve and piston move from the closed to open positions. In the open positions the fluid apertures in the circumferential face of the probe and socket respectively are in fluid communication and preferably aligned, as shown in Figures 5 and 6. In the open arrangement, the fluid passageways are sealed within the socket by either the first or second sealing means.

It will be appreciated that during transition of the fluid passageways between closed and open arrangements, the fluid passageways become unsealed so that seals either side of one of the fluid passageways on the circumferential face of the socket or probe seals to the probe on one side and the socket on the other. Consequently fluid is allowed to escape the fluid passageways. A third sealing means 130 is therefore provided to seal the socket and sleeve to prevent fluid loss. However, the fluid acts between the probe and piston and socket and sleeve to generate separation forces. Consequently a first pair of cooperating features 140 is provided to lock the sleeve and socket together and a second pair of cooperating features 150 is provided to lock the probe and piston together. The first and second pairs of cooperating features are engageable by relative movement in the coupling axis. In the Figure the first and second cooperating features are shown as a recess and protrusion pair. A recess is formed in one of the respective parts and a protrusion in the other. The protrusion is receivable in the recess and sized so as to fit therein. Importantly, abutment between the protrusion and recess prevents parts moving relative to each other in the actuating direction. Consequently, the male and female parts may be mated by relative movement in the coupling direction that brings the first and second cooperating features together by inserting the protrusion into the recess. Once both pairs of cooperating features are mated, the fluid passageways can be opened by moving the interlocked probe and piston relative to the interlocked socket and sheath. As the seals transition from fully sealed and closed to fully sealed and open, fluid is able to pressurise between the respective parts. Here, the parts are prevented from moving in the coupling axis by abutment of the probe within the socket and are prevented from moving relative to each other in the actuating axis by abutment of the cooperating features. The separation forces are therefore carried by the socket.

In the exemplary embodiments, the protrusion is a cylindrical feature and the recess a cylindrical bore. However, other cooperating shapes are envisaged. Moreover, the recess of the first cooperating feature and the recess of the second cooperating feature may be formed on the same one of the male or female member or may be formed on alternative members.

The first cooperating feature that locks the socket and sleeve together includes the third sealing means 130. Here the third sealing means seals between the pair of parts. That is between the recess and protrusion to prevent fluid egress. Suitably, the third seal is shown as a ring seal such as an o-ring. The ring seal may be attached to a groove in either f the protrusion or recess but is shown for ease of manufacture as being attached to a groove on the protrusion. Because the third seal prevents fluid egress a problem may occur due to a piston affect when inserting the protrusion into the recess. Fluid trapped between the two parts is prevented from escaping, thereby preventing insertion. In this case, a vent is provided to vent the recess to the environment. The vent is suitably a channel between a bottom of the recess and the outside if the coupling members. The vent may be formed in either part, but is shown in Figures 1 to 6 as being formed in the sleeve. As the protrusion is inserted in to the recess, ambient fluid within the recess is forced out of the vent. Suitably, the vent is arranged to be closed when the protrusion is fully mated with the recess. That is, when the piston and socket are aligned to allow transition of the seals. This is because as the seals transition, fluid within the pipeline comes into fluid communication with the vent as the seals cross the parts. Consequently, it is preferable for the vent to be shut to prevent fluid contamination. A particularly suitable vent mechanism will be described later..

A fourth sealing means 132 may be provided to seal between the pair of second cooperating features 150. Advantageously, this reduces the effective area of the fluid pressure generating the separation forces as the seals transition between the pressure balanced open and pressure balanced closed states. It will be appreciated that a reduction in effective area, reduces the separation forces. And therefore reduced the strength requirements of the socket and cooperating features. By sealing the second pair of parts, the second recess is no longer in fluid communication with the vent of the first recess and so a further vent is suitably provided to prevent the piston affect. The second vent does not necessarily need to be closeable as the fourth seal prevents the vent from being in fluid communication with the respective fluid passageways during transition. Again, the fourth sealing means is shown as being suitably a ring seal such as an o-ring and although it can be housed in a groove on either the protrusion or recess, for manufacturing ease, it is shown as assembled to the protrusion.

In the exemplary embodiments, the fluid passageways are shown as extending along the actuation axis with an elbow in each fluid passageway to exit the circumferential faces. The elbow transitions the fluid passageway through 90°. However other shaped fluid passageways are envisaged. The advantage to the elbow is that the coupling size can be minimised.

It will be appreciated that first and second sealing means may be any suitable sealing means to achieve the closing requirements of the passageways. Furthermore, the sealing means may be assembled to either of the parts. In the exemplary embodiments, the first and second sealing means are shown as a pair of ring seals. Suitably o-rings are used. The o- rings are housed in grooves and for ease of manufacture are suitably shown as being housed on the piston and probe respectively.

Referring to Figure 7, a further embodiment of a fluid coupling is shown. Here, the coupling still comprises male and female coupling members 210, 220 substantially as herein described. Further explanation of the common features is not therefore given. In addition, the coupling 200 includes a breakout mechanism. The breakout mechanism ties the piston 214 and socket 224 together when mated to prevent relative movement. In Figure 7, the breakout mechanism is shown as a tension pin 262. The tension pin is secured to the piston at one end and the socket at the other. The tension pin is arranged parallel to the actuating direction. When a tensile load is applied to the coupling in an attempt to decouple the coupling, movement id the actuating direction to decouple is resisted by the tension pin. At a predetermined load, the tension pin is arranged to fracture as is known in the art to allow decoupling.

Figure 8 shows a further exemplary embodiment of a coupling 300. The coupling 300 comprises a male and female member 310, 320. In this embodiment, the members each include multiple passageways as herein described. Thus multiple passageways may be coupled in a single stab. Figures 9 and 10 exemplify the connection process of the three port coupling 300. The coupling members operate in a similar mode to the single passageway embodiment, wherein a body includes multiple sockets formed in parallel. Pistons are assembled in each socket and the pistons may be connected together at an outside of the socket block. The male member includes a body including multiple sheaths for each probe. The probes are joined together in parallel. It will be appreciated that the coupling operation follows the same principles as a single passageway coupling. As is known in the art, an alignment mechanism may be provided to help align the male and female members for coupling.

Figures 1 1 and 12 show an enlarged portion of the probe including an exemplary vent 400. A fluid channel is formed in one of the parts, shown as the probe. The fluid channel is an open channel that vents fluid from the space between the piston and probe to the external environment. The other part, shown as the piston includes the vent 400 which closes the fluid channel in the other part when the probe and socket are aligned for movement in the actuating direction. The vent 400 includes a body 410 that houses a closing member 420. The closing member is moveable in the housing and is arranged to abut the mouth of the fluid aperture to close it when the two parts are mated. In doing so the closing member may move slightly into the housing to ensure a good seal each time. The body includes a fluid path from a front face including the projecting closing member to a space behind the closing member. The space is formed in the body. Fluid is therefore caused to enter the space behind the closing member and the fluid pressure from the pipe line therefore helps to urge the closing member against the mouth of the aperture. In the exemplary embodiments, the body 410 is shown as a cylindrical member having a bore in which the closing member sits. The outside of the cylindrical member may include a thread for attachment to the coupling member. The closing member 420 projects from a restricted end that acts to keep the closing member retained within the housing. The fluid path is suitably formed from a flat section 412 formed in the cylindrical body and an adjoining aperture through the wall of the body. Although preferred embodiment(s) of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made without departing from the scope of the invention as defined in the claims.