Coupling device

The invention relates to a coupling device including a coupling part provided with a coupling member and having an internal bore extending through the coupling part and its coupling member, wherein the coupling part is provided with a valve, which includes a valve body displaceably arranged inside the internal bore and a spring member acting on the valve body, the valve body being displaceable against the action of the spring member from a first position to a second position. The valve includes a housing fixed inside the internal bore, the housing being provided with a cavity accommodating the spring member and a part of the valve body. The cavity is in fluid communication with an orifice at the end of the valve facing the free end of the coupling member so as to allow the cavity to be in fluid communication with the surroundings via the orifice when the coupling member is out of engagement with a corresponding coupling member.

CROSS-REFERENCE TO RELATED APPLICATIONS

FIELD OF THE INVENTION

The present invention relates to a coupling device.

BACKGROUND OF THE INVENTION

A coupling device according to the preamble of claim1is previously known from GB 2293221 A. This coupling device comprises a male coupling part, a corresponding female coupling part and an intermediate metal seal. The metal seal is preloaded by urging said coupling parts against each other. The male coupling part is provided with two projections which fit into helical grooves in the female coupling part, and the coupling parts are urged towards each other by a rotation of the male coupling part in relation to the female coupling part. In the coupling device according to GB 2293221 A, a valve of the type indicated in the preamble of claim1is arranged in the female coupling part. The spring member urging the valve body towards its advanced position, in which position the valve body closes the internal bore of the female coupling part, is arranged inside the internal bore in contact with the fluid therein. Consequently, the valve body will be subjected to the force from the spring member as well as the forces from the fluid pressure inside the internal bore. If the female coupling part is disconnected from the male coupling part there is a risk that the external pressure from the surrounding medium will cause an inwardly directed force on the valve body that exceeds the combined forces from the spring member and the fluid pressure inside the internal bore, in which case the valve body will be unable to close the internal bore and prevent an undesired exchange of fluids between the surroundings and the internal bore. This could for instance ensue when the coupling device is installed in a subsea environment at a great depth.

In this description and the subsequent claim, the term “fluid” refers to a flowing medium in gaseous or liquid form. Consequently, the expression “fluid-tight seal” implies a seal that is liquid-tight as well as gas-tight.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a coupling device that eliminates the above-indicated drawback.

According to the invention, this object is achieved by a coupling device characterized inthat the valve comprises a housing which is fixed inside the internal bore of the first coupling part, said housing being provided with a cavity accommodating the spring member and a part of the valve body, andthat said cavity is in fluid communication with an orifice at the end of the valve facing the free end of the first coupling member so as to allow the cavity to be in fluid communication with the surroundings via said orifice when the first coupling member is out of engagement with the corresponding second coupling member.

Hereby, said cavity will have an internal pressure corresponding to the external pressure of the surrounding medium, which implies that the valve will be pressure balanced and insignificantly sensitive to differences between the pressure of the fluid in the internal bore and the pressure of the surrounding medium, given that the internal and external pressure respectively are effecting a cross sectional area having the same size, which reduces the risk of troubles in connection with the actuation of the valve during interconnection or disconnection of the coupling parts. When the coupling device is used in a subsea installation, said cavity will be filled with seawater of the same pressure as the surrounding seawater.

A preferred embodiment of the inventive coupling device is characterized inthat the valve body comprises a first body part and a second body part, said first body part being located in front of the second body part as seen in a direction along the internal bore of the first coupling part towards the first coupling member,that a first flow path section is provided radially outwardly of the first body part between the valve housing and an inner wall of the internal bore of the first coupling part, and a second flow path section is provided between the second body part and said inner wall, said first and second flow path sections extending essentially in the axial direction of the internal bore of the first coupling part on mutually different levels as seen in the radial direction of the internal bore,that the first flow path section is connected to the second flow path section via an intermediate flow path section extending obliquely in relation to the first and second flow path sections, andthat the first body part is adapted to block the intermediate flow path section when the valve body is displaced from said second position to said first position.

Hereby, the valve body will not be subjected to any axial forces by the fluid inside the internal bore of the first coupling part acting against the displacement of the valve body from said first position to said second position, which will facilitate the displacement of the valve body in connection with the interconnection of the coupling parts.

According to another preferred embodiment of the invention, the valve is provided with a ring-shaped sealing element arranged in an annular groove, which groove is provided in the inner wall of the internal bore of the first coupling part, an external surface of the valve body being adapted to engage with the sealing element so as to form a fluid-tight seal between the inner wall of the internal bore of the first coupling part and the valve body when the valve body is in said first position. Hereby, the internal bore of the first coupling part is sealed from the surroundings in a simple and efficient manner when the coupling device is disassembled.

Another preferred embodiment of the inventive coupling device is characterized in that the second body part has a smaller cross-sectional area than the first body part, that the second body part is surrounded by the sealing element and out of engagement therewith when the valve body is in said second position, that an external surface of the first body part is adapted to be brought into engagement with the sealing element so as to form a fluid-tight seal between the inner wall of the internal bore of the first coupling part and the valve body when the valve body is displaced from said second position to said first position, and that the end of the first body part facing the second body part only has blunt edges so that the sealing element will meet no sharp edge when the valve body is displaced between said positions. Hereby, the sealing element will only be subjected to minor wear by the valve body during the displacement of the valve body between said positions.

According to another preferred embodiment of the invention, the actuation member of the second coupling part is adapted to restrict the flow through the orifice when the first coupling member is in engagement with the second coupling member. Hereby, the fluid in the cavity accommodating the spring member will be prevented from mixing with the fluid flowing through the coupling device when the coupling device is assembled.

According to another preferred embodiment of the invention, said cavity is adapted to allow external pressure from surrounding medium to effect a cross sectional area which is identical to the cross sectional area effected by the internal fluid pressure, the two pressurised fluid media being sealed off from each other by a radial sealing element preferably arranged in an annular groove, which groove is provided in an internal surface being a part of the valve. Hereby, conditions for the valve to be pressure balanced is created.

According to another preferred embodiment of the invention, said cavity is in fluid communication with the orifice via a channel extending through the valve body, and the actuation member is adapted to engage with the valve body so as to cover the orifice and thereby restrict the flow through the orifice when the first coupling member is in engagement with the second coupling member. Hereby, the actuation member will automatically restrict the flow of fluid into and out of the cavity when the coupling device is assembled.

Another preferred embodiment of the inventive coupling device is characterized inthat the second coupling member has an external spherical contact surface of metallic material, the first coupling member being provided with a corresponding internal conical contact surface of metallic material for engagement with the spherical contact surface of the second coupling member, andthat the spherical contact surface of the second coupling member and the corresponding conical contact surface of the first coupling member are designed to form a fluid-tight seal between the first coupling part and the second coupling part when said contact surfaces are pressed against each other.

When the coupling device is assembled, i.e. when the coupling parts are pressed against each other, the mutually contacting coupling members form a metal seal which is capable of providing a reliable sealing effect even when the coupling parts and the associated coupling members are somewhat out of alignment with each other. Furthermore, by having a spherical contact surface and a corresponding conical contact surface at each end of the second coupling part, the sealing principle is that of compliancy with angular relative tolerances and eccentricity between the coupling parts, rather than forced axial alignment. This allows for less stringent tolerances to be accepted by the coupler device.

Further advantages as well as advantageous features of the coupling device according to the present invention will appear from the following description and the dependent claims.

A coupling device100according to the present invention is illustrated inFIG. 1. This coupling device comprises a first coupling part30, which is provided with a female first coupling member31and has an internal bore32extending through the coupling part30and the first coupling member31, and a second coupling part20, which is provided with a male second coupling member21band has an internal bore22extending through the coupling part20and the second coupling member21b.The coupling device100further comprises valve means for automatically closing the internal bore32of the first coupling part30when the second coupling part20is brought out of engagement with the first coupling part and automatically opening said internal bore when the second coupling part is brought into engagement with the first coupling part.

According to the invention, the first coupling part30is provided with a valve40, which comprises a valve body41displaceably arranged inside the internal bore32of the first coupling part and a spring member42acting on the valve body. The valve body41is displaceable against the action of the spring member42from a first position, in which the valve is closed and prevents fluid flow through the internal bore32of the first coupling part, to a second position, in which the valve is open and allows fluid flow through the internal bore of the first coupling part. The second coupling part20is provided with an actuation member25for displacing the valve body41from said first position to said second position immediately before the first coupling member31is brought into engagement with the corresponding second coupling member21b.The actuation member25consists of a body fixed inside the internal bore22of the second coupling part, while allowing fluid to pass through the body via axial openings in the body and/or via areas between the external surface of the body and the inner wall of the bore22. The actuation member25displaces the valve body41simply by pushing it inwards in the internal bore32of the first coupling part as the actuation member is moved towards the first coupling part together with the second coupling part.

The valve40comprises a housing43which is fixed, i.e. immovable mounted, inside the internal bore32, of the first coupling part30by means of a fastening element52, which is secured to the rear end of the housing43via a hub53and secured inside the bore32. The fastening element52is tube-shaped so as to allow fluid to pass through it. The housing43has a cylindrically shaped front part with an opening at the forward end so as to form a cavity44, which accommodates the spring member42and a rear part of the valve body41. The valve body41forms a piston slidingly received in the cylindrical part of the housing43. The spring member42is fixed between the rear end of the cavity44and the rear end of the valve body41so as to urge the valve body forward in the direction towards the free end of the first coupling part. The cavity44is in fluid communication with an orifice45at the end of the valve facing the free end of the first coupling part so as to allow the cavity to be in fluid communication with the surroundings via said orifice when the first coupling part30is out of engagement with the second coupling part20. The cavity44is in fluid communication with the orifice45via a channel46extending axially through the valve body41.

The actuation member25is adapted to restrict the flow through the orifice45when the first coupling member31is in engagement with the corresponding second coupling member21b.In the illustrated embodiment, this is accomplished in that the actuation member25is adapted to engage with the valve body41so as to cover the orifice45and thereby restrict the flow through the orifice when the first coupling member31is in engagement with the corresponding second coupling member21b.

In the embodiment illustrated inFIGS. 1 and 2, the valve body41comprises a first body part41aand a second body part41b,said first body part41abeing located in front of the second body part41bas seen in a direction along the internal bore32towards the first coupling member31, i.e. towards the free end of the first coupling part30. InFIG. 1, the flow path through the first female coupling part30is illustrated in a broken line. A first flow path section51ais provided radially outwardly of the first body part41abetween the valve housing43and the inner wall49of the internal bore32, and a second flow path section51bis provided between the second body part41band said inner wall49, said first and second flow path sections51a,51bextending essentially in the axial direction of the internal bore32on mutually different levels as seen in the radial direction of the internal bore. The first flow path section51ais connected to the second flow path section51bvia an intermediate flow path section51cextending obliquely in relation to the axial direction of the internal bore32and thereby obliquely to the first and second flow path sections51a,51b.The first body part41ais adapted to allow fluid flow through the intermediate flow path section51cwhen the valve body41is in its retracted second position, as illustrated inFIG. 1, and to block the intermediate flow path section51cwhen the valve body41is displaced from said second position to its advanced first position, as illustrated inFIG. 2. The intermediate flow path section51cis defined partly by an external surface50cof the valve body41which extends obliquely, as seen in the axial direction of the valve body41, between the first body part41aand the second body part41b.

The valve40is provided with a ring-shaped sealing element47aarranged in an annular groove48provided in the inner wall49of the internal bore32. An external surface50of the first part41aof the valve body is adapted to engage with the sealing element47aso as to form a fluid-tight seal between the inner wall49of the internal bore32and the valve body41when the valve body is in its advanced first position, as illustrated inFIG. 2. The second body part41bhas a smaller cross-sectional area than the first body part41aand is surrounded by the sealing element47aand out of engagement therewith when the valve body is in said second position, as illustrated inFIG. 1. The external surface of the first body part41ais adapted to be brought into engagement with the sealing element47aso as to form said fluid-tight seal when the valve body is displaced from said second position to said first position. In order to reduce wear on the sealing element47a,the end of the first body part41afacing the second body part41bonly has blunt edges so that the sealing element47awill meet no sharp edge when the valve body is displaced between said positions.

The coupling device100might also comprise a third coupling part10identical with the above-mentioned first coupling part30, as indicated with broken lines inFIG. 1. This third coupling part10is consequently provided with a female coupling member11and has an internal bore12extending through the coupling part10and the coupling member11. The third coupling part10is further provided with a valve, not shown, identical with the above-described valve40of the first coupling part30. The internal bore12,32of the respective coupling part10,30ends at an opening15,35provided at the outer end of the associated coupling member11,31. The respective coupling part10,30is here tube-shaped. In this case, the second coupling part20is provided with a male coupling member21aat a first end thereof and another male coupling member21bat a second end thereof, opposite said first end. The second coupling part20has its internal bore22extending through the coupling part20and both of its coupling members21a,21b.The internal bore22ends at openings25a,25bprovided at the respective outer end of the male coupling members21a,21b.Consequently, the male coupling members21a,21bare connected to each other via the internal bore22.

In the illustrated embodiment, the male coupling members21a,21bare each provided with an external spherical contact surface23a,23bof metallic material and the female coupling members11,31are each provided with a corresponding internal conical contact surface13,33of metallic material for engagement with the spherical contact surface23a,23bof the corresponding male coupling member21a,21b.The respective spherical contact surface23a,23bof the male coupling members21a,21band the conical contact surface13,33of the corresponding female coupling member11,31are designed to form a fluid-tight seal between the second coupling part20and the corresponding coupling part10,30when said contact surfaces23a,13and23b,33are pressed against each other. It is realised that the contact surfaces13,23a,23b,33should have a suitable surface smoothness, and may have a thin layer of metal coating, galvanically applied, to improve surface finishing, so as to allow a fluid-tight contact between said contact surfaces. The respective contact surface13,23a,23b,33is suitably of a corrosion resistant metallic material.

When the respective pair of coupling members11,21aand31,21bare pressed against each other so as to form a seal between the male coupling member21a,21band the corresponding female coupling member11,31, said internal bores12,22,32will be interconnected so as to allow an internal flow of fluid through the coupling parts10,20,30. The internal flow channel formed by these internal bores12,22,32will consequently be sealed from the surroundings by the seal formed between the respective pair of coupling members. The female coupling parts10,30are e.g. intended to be connected to a respective fluid carrying conduit, so as to allow for an interconnection of these conduits.

At least one of the first and third coupling parts10,30is displaceable in the axial direction towards and away from the opposite coupling part30,10so as to make possible the assembling and disassembling of the coupling device. When the coupling device is to be assembled, the second coupling part20is located in the area between the first and third coupling parts10,30, whereupon the latter coupling parts10,30are mutually displaced towards each other so as to clamp the second coupling part between them and establish the required sealing contact pressure between the respective male coupling member and the corresponding female coupling member. The first and third coupling parts10,30are then secured in relation to each other. This displacing and securing of the coupling parts may be accomplished by any suitable means, which means will be described further below by way of example in connection toFIGS. 3 and 4. It is realised that the coupling device is disassembled in the opposite order. During the operations of assembling and disassembling, the second coupling part20is suitably held in place axially by means of a suitable holder60(retainer plate), as illustrated inFIG. 1. The second coupling part20may hereby be independently retrieved for replacement or maintenance, i.e. without having to retrieve either of the first and third coupling parts10,30.

In the illustrated embodiment, the male coupling member21ais connected to the other male coupling member21bvia an intermediate member24, which forms a continuous part together with the male coupling members and which is mechanically compressible so as to be capable to store elastic energy when the second coupling part20is subjected to compression between the first coupling part10and the, third coupling part30. The intermediate member24has an internal cross-sectional area which is larger than the external cross-sectional area of the respective male coupling member21a,21bas seen at the point P of the male coupling member where the male coupling member engages with the corresponding female coupling member11,31. Hereby, the intermediate member24is expandable in the axial direction of the second coupling part20by an internal fluid pressure in the coupling device100, i.e. a fluid pressure inside the internal bore22, so as to urge the respective male coupling member21a,21bagainst the corresponding female coupling member11,31, thereby increasing the sealing contact pressure between the respective male coupling member and the corresponding female coupling member. The intermediate member24is suitably of metallic material and is preferably essentially shaped as a single or multiple wave bellows. In the illustrated embodiment, the intermediate member is shaped as a single wave bellows. It is realised that the intermediate member24should have a wall thickness thin enough to give the intermediate member24the desired mechanical stiffness so as to allow for the axial compressions and expansions thereof, still maintaining safe allowable stresses and deflections.

The coupling device100of the present invention is suitable for use as a hydraulic subsea coupling, e.g. for coupling together conduits belonging to interconnectable processing modules in a fluid-tight manner. It should, however, be evident to a person skilled in the art that the coupling device according to the present invention may be used for many other purposes where a flexible and fluid-tight seal is required.

An alternative embodiment of a coupling device according to the present invention is illustrated inFIG. 3. This coupling device comprises two female coupling parts10,30, an intermediate male coupling part20and associated coupling members11,21a,21b,31with contact surfaces13,23a,23b,33of the configurations described with reference toFIGS. 1 and 2. The female coupling parts10,30are further provided with valves40(not shown inFIG. 3) and the male coupling part20is provided with an actuation member25(not shown inFIG. 3) of the configurations described with reference toFIGS. 1 and 2. The coupling device is here provided with a clamping arrangement70for securing the two female coupling parts10,30in relation to each other with the male coupling part20clamped between them. The clamping arrangement70comprises a first flange ring71aand a second flange ring71b.The first flange ring71ais secured on the outside of the first female coupling part10in engagement with the external wall thereof. The flange ring71acomprises an inwardly protruding part72awhich is received between a flange73asurrounding the outer free end of the coupling part10and a retaining ring74aarranged in a groove75ain the external wall of the coupling part10. The second flange ring71bis secured on the outside of the second female coupling part30in engagement with the external wall thereof. The flange ring71bcomprises an inwardly protruding part72bwhich is received between a flange73bsurrounding the outer free end of the coupling part30and a retaining ring74barranged in a groove75bin the external wall of the coupling part30. The respective flange ring71a,71bis provided with an outwardly protruding part76a,76breceived in an annular recess77of a clamp shell78. The clamp shell78is arranged to surround the protruding parts76a,76bof the flange rings71a,71b.The flange rings71a,71bare forced towards each other by pressing the clamp shell inwards, due to the engagement between the inclined side walls78a,78bof the recess77and the corresponding inclined side walls79a,79bof the protruding parts76a,76b.The clamping arrangement70also comprises a seal retainer plate80received inside a recess81formed between the first flange ring71aand the second flange ring71b.The seal retainer plate80is provided with an annular inner recess82surrounding the intermediate member24of the male coupling part20and accommodating the outer edge of the bellows of said intermediate member24.

Another alternative embodiment of a coupling device according to the present invention is illustrated inFIG. 4. This coupling device comprises two female coupling parts10,30, an intermediate male coupling part20and associated coupling members11,21a,21b,31with contact surfaces13,23a,23b,33of the configurations described with reference toFIGS. 1 and 2. The female coupling parts10,30are further provided with valves40(not shown inFIG. 4) and the male coupling part20is provided with an actuation member25(not shown inFIG. 4) of the configurations described with reference toFIGS. 1 and 2. The coupling device is here provided with a bolted securing arrangement90for securing the two female coupling parts10,30in relation to each other with the male coupling part20clamped between them. The clamping arrangement90comprises a first flange ring71a′ and a second flange ring71b′. The first flange ring71a′ is secured on the outside of the first female coupling part10in engagement with the external wall thereof. The flange ring71a′ comprises an inwardly protruding part72a′ which is received between a flange73a′ surrounding the outer free end of the coupling part10and a retaining ring74a′ arranged in a groove75a′ in the external wall of the coupling part10. The second flange ring71b′ is secured on the outside of the second female coupling part30in engagement with the external wall thereof. The flange ring71b′ comprises an inwardly protruding part72b′ which is received between a flange73b′ surrounding the outer free end of the coupling part30and a retaining ring74b′ arranged in a groove75b′ in the external wall of the coupling part30. The respective flange ring71a′,71b′ is provided with an outwardly protruding part76a′,76b′. The securing arrangement90also comprises a seal retainer plate80′ received between the first flange ring71a′ and the second flange ring71b′. The seal retainer plate80′ is provided with an annular inner recess81′ surrounding the intermediate member24of the male coupling part20and accommodating the outer edge of the bellows of said intermediate member24. A number of bolts91are each arranged in a respective set of mutually aligned through holes92a,92b,92cextending through the flange rings71a′,71b′ and the intermediate seal retainer plate80′ in the axial direction of the coupling parts10,20,30. The flange rings71a′,71b′ and the intermediate seal retainer plate80′ are pressed against each other and secured to each other by means of these bolts91, thereby securing the coupling parts10,20,30to each other.

FromFIG. 1which shows the valve of the first coupling part in an open position andFIG. 2which shows the valve of the first coupling part in a closed position, it is realized that the coupling device according to the present invention makes use of radial sealing elements for opening and closing of the flowing through of the fluid.

The invention is of course not in any way restricted to the preferred embodiments described above. On the contrary, many possibilities to modifications thereof will be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention such as defined in the appended claims.