GB2580038A

GB2580038A - Coupling

Info

Publication number: GB2580038A
Application number: GB1820740.7A
Authority: GB
Inventors: Higgins Steven
Original assignee: Gall Thomson Environmental Ltd
Current assignee: Gall Thomson Environmental Ltd
Priority date: 2018-12-19
Filing date: 2018-12-19
Publication date: 2020-07-15
Anticipated expiration: 2038-12-19
Also published as: GB2580038B; GB201820740D0

Abstract

A coupling 20 for releasably coupling two objects such as pipelines, comprises first and second coupling sections 22 24, with two different fastening arrangements (32, 34, 30). The first fastening arrangement has a predetermined maximum load, after which the fastening arrangement will disengage, and may comprise a breakstud (28, figure 3) and a nut 30. The second fastening arrangement has an actuation means (such as a hydraulic actuator) which may selectively engage and disengage the second fastening means. When the second fastening means is disengaged, the first fastening means will separate at the predetermined maximum load, and the coupling will separate. When the second fastening means is engaged, the coupling will not separate at the predetermined maximum load. The second fastening means may comprise a hydraulic nut 34. In some embodiments the coupling is a breakaway coupling for fluid transfer, and has shut-off valves 26 in both coupling sections.

Description

COUPLING

This invention relates to a coupling, preferably for use as a pipeline coupling, further preferably for use as a breakaway coupling or a release coupling.

It is known to use a coupling to releasably connect two objects together.

According to an aspect of the invention, there is provided a coupling, for releasably connecting two objects together, comprising: first and second coupling sections; at least one first fastening arrangement for securing the coupling sections to each other; at least one second fastening arrangement for securing the coupling sections to each other; and an actuation mechanism operably coupled with the or each second fastening arrangement, wherein the or each second fastening arrangement includes a longitudinal fastening member and a fastening nut, the or each fastening nut configured to be engageable with the corresponding longitudinal fastening member to secure the coupling sections to each other, the or each fastening nut configured to be disengageable from the corresponding longitudinal fastening member, wherein the actuation mechanism includes a or a respective driving assembly configured to, in use, mechanically drive the or each fastening nut so as to: engage the or each fastening nut with the corresponding longitudinal fastening member; and/or disengage the or each fastening nut from the corresponding longitudinal fastening member, wherein the coupling has a predetermined allowable tensile load rating that is defined by the or each first fastening arrangement securing the coupling sections to each other and the or each second fastening arrangement configured to disengage the or each fastening nut from the corresponding longitudinal fastening member, the or each first fastening arrangement configured to be releasable to cause separation of the coupling sections upon exposure of the coupling to a tensile load exceeding the predetermined allowable tensile load rating, and wherein configuration of the first and second fastening arrangements to secure the coupling sections to each other inhibits release of the or each first fastening arrangement when the coupling is exposed to a tensile load exceeding the predetermined allowable tensile load rating.

The coupling according to the invention may be used to releasably connect a wide variety of objects together. Such objects may include, but are not limited to, sections of a fluid conduit (such as a pipeline or hose), a cable, and a rope. The fluid conduit may be flexible or rigid.

The configuration of the coupling according to the invention results in a reconfigurable coupling that can readily switch between first and second modes, wherein the first mode of the coupling includes configuration of the or each first fastening arrangement to secure the coupling sections to each other, and configuration of the or each second fastening arrangement to disengage the or each fastening nut from the corresponding longitudinal fastening member, and wherein the second mode of the coupling includes configuration of the first and second fastening arrangements to secure the coupling sections to each other.

In the first mode of the coupling, the or each first fastening arrangement provides a passive means of enabling an automatic separation of the coupling sections in response to the coupling being exposed to a tensile load exceeding the predetermined allowable tensile load rating, which for example may occur as a result of unexpected movement of objects connected to the coupling or due to excessive force applied to the coupling sections.

Through the automatic separation of the coupling sections, the coupling is able to reliably limit the amount of damage to the objects connected to the coupling, which would otherwise be significant if the or each first fastening arrangement is incapable of being released to cause automatic separation of the coupling sections upon exposure of the coupling to a tensile load exceeding the predetermined allowable tensile load rating.

On the other hand, it may be desirable under certain circumstances for the coupling sections to stay connected to each other when the coupling is exposed to a tensile load exceeding the predetermined allowable tensile load rating. Such circumstances include, but are not limited to, installation, maintenance, repair, servicing, and transport of the coupling which may generate tensile loads larger than the predetermined allowable tensile load rating. The second mode of the coupling results in a temporary increase of the tensile load capacity of the coupling beyond the predetermined allowable tensile load rating. This thereby prevents premature release of the or each first fastening arrangement when the coupling is exposed to a tensile load exceeding the predetermined allowable tensile load rating, thus obviating the need to reset or replace the or each first fastening arrangement before reconfiguring the coupling to the first mode.

Conventionally, the tensile load capacity of a coupling is temporarily increased beyond the predetermined allowable tensile load rating through use of conventional nut and bolt arrangements. The coupling according to the invention is advantageous over conventional couplings for the following reasons.

The coupling according to the invention improves safety by enabling remote operation of the or each driving assembly to mechanically drive the or each fastening nut. This is because the conventional coupling must be directly accessed in order to install, remove and tension the bolts, which often requires personnel to use torque wrenches and position themselves in unsatisfactory ergonomic positions at an increased risk to their personal safety. This is particularly dangerous when the coupling is located in unsafe environments, such as underwater.

In addition, when the coupling according to the invention comprises a plurality of second fastening arrangements, the coupling according to the invention reduces operational time by enabling operation of the or each driving assembly to mechanically drive two or more of the plurality of second fastening nuts at the same time. In contrast, conventional couplings require the installation, removal and tensioning of the bolts to be carried out one at a time in accordance with a recommended bolting pattern. Moreover, in the conventional coupling, the difficulty in accessing some bolts increases the overall operational time, which is addressed by the current invention through remote operation of the or each driving assembly to mechanically drive the or each fastening nut.

Also, the provision of the or each second fastening arrangement and the actuation mechanism in the coupling of the invention obviates the costs of providing and operating additional infrastructure and equipment associating with conventional couplings. This is because conventional couplings often require additional architecture in the form of platforms to help personnel to gain access to its bolts, and submerged conventional couplings require personnel to use diving equipment to access its bolts.

Furthermore, the or each second fastening arrangement can be installed in the coupling without requiring removal or relocation of the or each first fastening arrangement, and thus can be retrofitted to existing couplings that comprise one or more first fastening arrangements to secure their coupling sections together.

In embodiments employing the use of multiple driving assemblies in the actuation mechanism, the multiple driving assemblies may be formed separately or may be part of the same driving system.

In a preferred embodiment of the invention, the or each first fastening arrangement includes a weakened portion that breaks on exposure of the coupling to a tensile load exceeding the predetermined allowable tensile load rating. Such a first fastening arrangement may be in the form of, for example, a breakstud. This provides a reliable means of releasing the or each first fastening arrangement to cause the automatic separation of the coupling sections in response to the coupling being exposed to a tensile load exceeding the predetermined allowable tensile load rating. Also, the coupling of the invention advantageously protects the or each first fastening arrangement from premature breakage through reconfiguration of the coupling to the second mode in order to withstand tensile loads above the predetermined allowable tensile load rating.

The or each longitudinal fastening member may vary in terms of type and configuration.

The or each longitudinal fastening member may be a stud, bolt or pin. The or each longitudinal fastening member may be any one of: * a threaded longitudinal fastening member; * a barbed longitudinal fastening member; * a top hat longitudinal fastening member; * a longitudinal fastening member with a circumferential shoulder formed thereon; * a longitudinal fastening member with a circumferential cut-out section formed therein; * a longitudinal fastening member with a circumferential groove formed thereon; * a longitudinal fastening member with a circumferential tapered section formed therein; * a longitudinal fastening member with a circumferential scalloped section formed therein.

The coupling sections may be directly secured to each other. For example, the or each fastening arrangement may secure adjacent portions of the coupling sections to each other.

Alternatively, the coupling sections may be indirectly secured to each other. For example, the coupling may further include an additional coupling section, such as a collar, arranged between the coupling sections, where the coupling sections are secured to each other via the intermediate additional coupling section.

The configuration of the or each fastening nut may vary.

For example, the or each fastening nut may include outer and inner nut portions, the outer nut portion enclosing the inner nut portion and including an inner face with a cavity formed therein, the outer nut portion configured to be movable between first and second positions to alter the position of the cavity relative to the inner nut portion, wherein the inner face of the outer nut portion may be configured to push the inner nut portion inwards to grip the corresponding longitudinal fastening member when the outer nut portion is in its first position, and the cavity formed in the inner face may be positioned to permit outward expansion of the inner nut portion into the cavity when the outer nut portion is in its second position, and wherein the or each driving assembly may be configured to, in use, mechanically drive the corresponding outer nut portion to move between its first and second positions.

In embodiments of the invention, the or each fastening nut may be a hydraulic or pneumatic nut, and the or each driving assembly may include a hydraulic or pneumatic actuator configured to, in use, control a hydraulic or pneumatic pressure of the or each fastening nut.

The configuration of the or each fastening nut as a hydraulic or pneumatic nut provides an effective means of not only configuring the or each fastening nut to be in engagement with the corresponding longitudinal fastening member to reliably secure the coupling sections to each other, but also disengaging the or each fastening nut from the corresponding longitudinal fastening member on demand.

Alternatively, the or each fastening nut may take the form of a different type of nut that can be mechanically driven to disengage the or each fastening nut from the corresponding longitudinal fastening member.

Optionally, the hydraulic or pneumatic actuator of the or each driving assembly may be configured to, in use, control a hydraulic or pneumatic pressure of the or each fastening nut to mechanically drive the or each fastening nut so as to: engage the or each fastening nut with the corresponding longitudinal fastening member; and/or disengage the or each fastening nut from the corresponding longitudinal fastening member.

Further optionally, when the or each fastening nut includes the outer and inner nut portions, the or each fastening nut may include a first chamber hydraulically or pneumatically connected to the hydraulic or pneumatic actuator of the or the respective driving assembly, the first chamber of the or each fastening nut arranged so that, in use, a hydraulic or pneumatic pressure in the first chamber is controllable to drive the corresponding outer nut portion to move between its first and second positions.

In a first example of driving the corresponding outer nut portion to move between its first and second positions, the hydraulic or pneumatic actuator of the or each driving assembly may be configured to, in use, increase the hydraulic or pneumatic pressure in the first chamber of the or the respective fastening nut to cause the corresponding outer nut portion to move to its first position.

In a second example of driving the corresponding outer nut portion to move between its first and second positions, the hydraulic or pneumatic actuator of the or each driving assembly may be configured to, in use, decrease the hydraulic or pneumatic pressure in the first chamber of the or the respective fastening nut to permit the corresponding outer nut portion to move to its second position.

In further embodiments of the invention, the or each driving assembly may include a biasing element configured to apply a biasing force that tends to urge the or each fastening nut so as to disengage the or each fastening nut from the corresponding longitudinal fastening member. In such embodiments, the or each driving assembly may be configured to, in use, mechanically drive the or each fastening nut by applying a driving force that overcomes the biasing force so as to engage the or each fastening nut with the corresponding longitudinal fastening member. Preferably, the biasing element is or includes a resilient member, such as a spring. The spring may be in the form of, for example, a coiled spring, a spring washer (e.g. a Belleville washer), or any other type of spring.

The provision of the biasing element in the or each driving assembly provides a reliable means of disengaging the or each fastening nut from the corresponding longitudinal fastening member.

In embodiments of the invention, the or each driving assembly may be configured to, in use, mechanically drive the or each fastening nut so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member. Hence, in addition to facilitating engagement of the or each fastening nut with the corresponding longitudinal fastening member and/or disengagement of the or each fastening nut from the corresponding longitudinal fastening member, the or each fastening nut may be configured to place the corresponding longitudinal fastening member under tension to enhance the securing of the coupling sections to each other.

When the coupling employs the use of the outer and inner nut portions in the or each fastening nut, the or each driving assembly may be configured to, in use, mechanically drive the corresponding inner nut portion so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.

When the coupling employs the use of the hydraulic or pneumatic actuator in the or each driving assembly, the or each hydraulic or pneumatic actuator may be configured to, in use, control a hydraulic or pneumatic pressure of the or each fastening nut to mechanically drive the or each fastening nut so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.

When the coupling employs the use of the outer and inner nut portions in the or each fastening nut and the hydraulic or pneumatic actuator in the or each driving assembly, the or each second fastening arrangement may include a second chamber hydraulically or pneumatically connected to the hydraulic or pneumatic actuator of the or the respective driving assembly, the second chamber of the or each fastening nut arranged so that, in use, a hydraulic or pneumatic pressure in the second chamber is controllable to mechanically drive the inner nut portion so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.

In embodiments of the invention employing the use of the first and second chambers in the or each fastening nut, the first and second chambers may be connected to a common port that is hydraulically or pneumatically connected to the hydraulic or pneumatic actuator.

Such connection of the first and second chambers to a common port not only simplifies the control of the hydraulic or pneumatic pressure in the first and second chambers using a common hydraulic or pneumatic actuator, but also permits the design of the first and second chambers to control the timings of the engagement of the fastening nut with the longitudinal fastening member and the application of the tensioning force to the longitudinal fastening member.

When the coupling includes a plurality of second fastening arrangements, the or each driving assembly may be configured to, in use, simultaneously mechanically drive the fastening nuts.

In embodiments of the invention, each coupling section may be or may include a flange, the or each first fastening arrangement may be for securing the flanges of the coupling sections to each other, and the or each second fastening arrangement may be for securing the flanges of the coupling sections to each other.

In further embodiments of the invention, the coupling may be a pipeline coupling, and each coupling section may be a pipeline section.

In such embodiments, the pipeline sections may define a hollow bore along which flowable material may flow, at least one shut-off valve located within the hollow bore, the or each shut-off valve including a valve member movable between a valve open position and a valve closed position in which the valve member shuts off the flow of a flowable material through the hollow bore, the or each valve member being biased to move to its valve closed position on separation of the pipeline sections.

In further such embodiments, the coupling may include a respective shut-off valve located within the hollow bore of each pipeline section, each shut-off valve including a valve member movable between a valve open position and a valve closed position in which the valve member shuts off the flow of a flowable material through the hollow bore, each valve member being biased to move to its valve closed position on separation of the pipeline sections.

The provision of the actuation mechanism to facilitate the engagement or disengagement of the or each fastening nut is particularly beneficial when it is difficult to access the or each second fastening arrangement, e.g. due to the location of the pipeline coupling along the pipeline.

Also, the second mode of the coupling can be beneficially utilised during reeling of the pipeline around a reel or unreeling of the pipeline from the reel, which can generate bending moments resulting in tensile loads beyond the predetermined allowable tensile load rating.

According to a further aspect of the invention, there is provided the use of a coupling as a breakaway coupling or a release coupling, wherein the coupling is in accordance with any one of the embodiments of the first aspect of the invention.

Breakaway and release couplings are known and are often used in situations where a pipeline may be exposed to a tensile loading which, in the absence of a breakaway or release coupling, could cause the pipeline to fracture. Typically, such a pipeline may be one used for carrying material (e.g. liquid or gas) between two locations, e.g. between ships or between a ship and a dock. If such a fracture occurs, the material being conveyed along the pipeline flows freely out of the fractured ends of the pipeline. This can cause significant spillage that is expensive to clear and may be environmentally undesirable. The presence of a breakaway or release coupling enables the pipeline to fracture at a specified location (i.e. at the coupling) and for spillage to be avoided by providing valves in the breakaway coupling which are actuated when the coupling breaks.

The configuration of the coupling of the invention is particularly beneficial when the coupling is in the form of a breakaway coupling or a release coupling. The second mode of the coupling inhibits activation of the breakaway or release coupling when the coupling is exposed to a tensile load exceeding the predetermined allowable tensile load rating, which as mentioned above can arise under certain circumstances such as installation, maintenance, repair, servicing, and transport of the coupling, and the coupling can be readily reconfigured to the first mode as needed in order to permit the breakaway or release coupling to perform its function.

In addition, for the same reasons outlined earlier in this specification, the configuration of the coupling of the invention provides the breakaway or release coupling with several advantages over conventional breakaway or release couplings by improving safety, reducing operational time, saving on infrastructure and equipment cost, and permitting its retrofitting to existing couplings.

According to an even further aspect of the invention, there is provided a method of using a coupling in accordance with any one of the embodiments of the first aspect of the invention, the method comprising the step of operating the or each driving assembly to reconfigure the coupling between first and second modes, wherein the first mode of the coupling includes configuration of the or each first fastening arrangement to secure the coupling sections to each other, and configuration of the or each second fastening arrangement to disengage the or each fastening nut from the corresponding longitudinal fastening member, and wherein the second mode of the coupling includes configuration of the first and second fastening arrangements to secure the coupling sections to each other.

The method of the invention may include the step of configuring the coupling in the second mode during installation, maintenance, repair, servicing, or transport of the coupling.

The method of the invention may include the step of configuring the coupling in the first mode to use the coupling as a breakaway coupling or a release coupling.

The advantages of the coupling of the invention and its embodiments apply mutatis mutandis to the method of the invention and its embodiments.

It Will be appreciated that the use of the terms "first" and "second" and the like in the patent specification is merely intended to help distinguish between similar features (e.g. the first and second coupling sections, the first and second fastening arrangements, the first and second chambers), and is not intended to indicate the relative importance of one feature over another feature, unless specified otherwise.

A preferred embodiment of the invention will now be described, by way of a non-limiting example, with reference to the accompanying drawings in which: Figure 1 schematically shows a pipeline coupling according to an embodiment of the invention; Figures 2 and 3 schematically show the pipeline coupling of Figure 1 in assembled and disassembled configurations; Figures 4 and 5 schematically show a fastening arrangement of the pipeline coupling of Figure 1; Figure 6 to 8 schematically show cross-sectional views of the fastening arrangement of Figures 4 and 5 in an engaged mode; Figure 9 to 11 schematically show cross-sectional views of the fastening arrangement of Figures 4 and 5 in a disengaged mode; and Figure 12 shows examples of longitudinal fastening members.

The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic form in the interests of clarity and conciseness.

The following embodiment of the invention is described with reference to a pipeline coupling for use in a pipeline, but it will be appreciated that the following embodiment of the invention is applicable mutatis mutandis to other types of couplings for releasably connecting other types of objects together.

A pipeline coupling according to an embodiment of the invention is shown in Figure 1, and is designated generally by the reference numeral 20. The pipeline coupling 20 is preferably for use as a breakaway coupling (such as a marine breakaway coupling) or a release coupling (such as an emergency release coupling).

The pipeline coupling 20 includes a pair of shut-off valve housings 22, 24 directly secured to each other by means of a plurality of first fastening arrangements.

The shut-off valve housings 22, 24 define a hollow bore along which flowable material may flow.

A respective shut-off valve is located within the hollow bore of each shut-off valve housing 22, 24, and each shut-off valve includes a shut-off valve member 26 movable between a valve open position and a valve closed position. In the valve open position, each shut-off valve member 26 bisects the hollow bore of the respective shut-off valve housing 22, 24.

In the valve closed position (not shown) the shut-off valve member 26 sealingly engages against a valve seat defined about the circumference of the respective shut-off valve housing 22, 24 and shuts off the flow of a flowable material through the hollow bore.

Each shut-off valve member 26 is biased to move to its valve closed position on separation of the shut-off valve housings 22, 24. Each shut-off valve member 26 is mounted on a pivot shaft and is biased to move to its valve closed position by means of a spring. The spring preferably includes contra wound spring portions mounted on opposite ends of the pivot shaft and engaged with the shut-off valve members 26 so as to bias each of the shutoff valve members 26 towards the valve closed position.

The shut-off valves are located in the shut-off valve housings 22, 24 in opposed configurations such that, whilst the shut-off valve housings 22, 24 are secured to each other, the opposing shut-off valve members 26 interleave with each other when they are in their valve open positions. This engagement allows each shut-off valve member 26 to oppose movement of the other shut-off valve member 26 until separation of the shut-off valve housings 22, 24 moves the shut-off valve members 26 out of engagement with each other and the bias provided by the springs causes the shut-off valve members 26 to move to their valve closed positions.

An abutment end of each of the shut-off valve housings 22, 24 is formed to define a flange extending about its circumference, the flanges defining opposed contact surfaces which on abutment of the shut-off valve housings 22, 24 are brought into abutting engagement.

Each first fastening arrangement includes a first longitudinal fastening member and a first fastening nut. Each first longitudinal fastening member is in the form of a breakstud 28. Each first fastening nut 30 is in the form of a conventional nut, which can be tightened and unfightened using a torque wrench.

To maintain the flanges in abutting engagement and thereby secure the shut-off valve housings 22, 24 to each other, each first fastening nut 34 is configured to be in engagement with the corresponding breakstud 28.

Each breakstud 28 is arranged to extend through respective apertures formed about the circumferences of the flanges of the shut-off valve housings 22, 24 when their abutment surfaces are in abutting engagement, with a portion of each breakstud 28 protruding above the flange surface of the first shut-off valve housing 22 and the other portion of each breakstud 28 anchored in place in the flange of the second shut-off valve housing 24.

Each first fastening nut 30 engages the protruding portion of the corresponding breakstud 28 such that each first fastening nut 30 is arranged adjacent to the flange surface of the first shut-off valve housing 22, with a washer located between the first fastening nut 30 and the flange surface of the first shut-off valve housing 22.

In this manner the shut-off valve housings 22, 24 are secured to each other via each first fastening arrangement in a first mode of the pipeline coupling 20. Figure 2 schematically shows the pipeline coupling 20 of Figure 1 when the shut-off valve housings 22, 24 are directly secured to each other.

Each breakstud 28 is formed to include a weakened portion that is designed to break on exposure to a tensile load exceeding a tensile load capacity of the breakstud 28. Such a tensile load may be applied to the pipeline as a result of unexpected movement of objects connected to the ends of the associated pipeline or due to excessive pressure within the pipeline. The sum of the tensile load capacities of the breakstuds 28 defines a predetermined allowable tensile load rating of the pipeline coupling 20.

The use of the breakstuds 28 with the respective weakened portions permits the automatic separation of the shut-off valve housings 22, 24 in response to the pipeline coupling 20 being exposed to a tensile load exceeding a predetermined allowable tensile load rating. More particularly, upon application of such a tensile load, each breakstud 28 breaks at its weakest section, thus permitting the second shut-off valve housing 24 to separate from the first shut-off valve housing 22 in order to trigger the movement of the shut-off valve members 26 to their valve closed positions to shut-off the respective hollow bores of the shut-off valve housings 22, 24. Such automatic separation is carried out independently of any control and/or monitoring system. Figure 3 schematically shows the pipeline coupling 20 of Figure 1 when the shut-off valve housings 22, 24 are separated from each other.

The pipeline coupling 20 further comprises a plurality of second fastening arrangements.

Each second fastening arrangement includes a second longitudinal fastening member and a second fastening nut. Each second longitudinal fastening member is in the form of a solid stud 32. Each second fastening nut is in the form of a hydraulic nut 34.

Each second fastening arrangement is arranged adjacent to a respective one of the first fastening arrangements, as shown in Figure 4. Figure 5 shows a partial cut-out view of each hydraulic nut 34.

The structure and operation of each hydraulic nut 34 is described as follows, with reference to Figures 6 to 11.

Each hydraulic nut 34 includes outer and inner nut portions 36, 38 The inner nut portion 38 is flanked by a pair of outwardly projecting wings 40. The outwardly projecting wings 40 rest on the flange surface of the first shut-off valve housing 22, while the inner nut portion 38 sits inside a recess formed in the flange surface of the first shut-off valve housing 22. A respective pin 42 extends through each outwardly projecting wing 40 and into a mating receptacle formed in the flange surface of the first shut-off valve housing 22. A respective coiled retention spring 44 is arranged coaxially with a respective one of the pins 42 such that one end of the retention spring 44 abuts the head of the pin 42 and the other end of the retention spring 44 engages the corresponding outwardly extending wing 40. This results in each corresponding outwardly extending wing 40 being pushed against the flange surface of the first shut-off valve housing 22, thereby securing each hydraulic nut 34 to the flange of the first shut-off valve housing 22.

It will be understood that each coiled retention spring 44 may be replaced by a non-coiled spring, a spring washer (e.g. a Belleville washer), or any other type of spring.

The outer nut portion 36 is in the form of a collar that is arranged to enclose the inner nut portion 38. The inner nut portion 38 includes a threaded insert with an internally threaded wall. A cavity 46 is formed in an inner face of a wall of the outer nut portion 36. The outer nut portion 36 is movable along the axis of the corresponding hydraulic nut 34 between first and second positions to alter the position of the cavity 46 relative to the internally threaded wall of the threaded insert.

When the outer nut portion 36 is in its first position (shown as the "down" position in Figure 6), the inner face of the wall of the outer nut portion 36 abuts the threaded insert so as to push the internally threaded wall of the threaded insert inwards. When the outer nut portion 36 is in its second position (shown as the "up" position in Figure 9), the inner face of the wall of the outer nut portion 36 no longer abuts the threaded insert, but instead the cavity 46 formed in the inner face is now positioned such that the internally threaded wall of the threaded insert is permitted to expand outwards into the cavity 46.

Each hydraulic nut 34 further includes a first hydraulic chamber 48 formed between the outer and inner nut portions 36, 38. The first hydraulic chamber 48 is arranged such that the outer nut portion 36 is in its second position when there is little to no hydraulic fluid in the hydraulic chamber 48. The first hydraulic chamber 48 is further arranged so that the introduction of hydraulic fluid into the first hydraulic chamber 48 results in an increase in volume of the first hydraulic chamber 48 and then an increase in hydraulic pressure of the first hydraulic chamber 48 that results in the application of an axial force on the outer nut portion 36, which in turn moves the outer nut portion 36 from its second position to its first position.

The pipeline coupling 20 includes an actuation mechanism having a plurality of driving assemblies, each of which includes a respective hydraulic actuator (not shown) capable of selectively controlling the flow of a volume of hydraulic fluid (e.g. oil) under pressure (not shown). Each hydraulic actuator is hydraulically connected to a port 50 of the corresponding inner nut portion 38. In turn the port 50 of each inner nut portion 38 is hydraulically connected to the corresponding first hydraulic chamber 48. This enables each hydraulic actuator to, in use, increase a hydraulic pressure of the corresponding first hydraulic chamber 48 in order to drive the corresponding outer nut portion 36 from its second position to its first position.

In use, each hydraulic nut 34 may be selectively configured to be in engagement with the corresponding solid stud 32 to secure the shut-off valve housings 22, 24 to each other.

Each solid stud 32 is arranged to extend through respective apertures formed about the circumferences of the flanges of the shut-off valve housings 22, 24 when their abutment surfaces are in abutting engagement, with a portion of each solid stud 32 protruding above the flange surface of a first of the shut-off valve housings 22, 24 and the other portion of each solid stud 32 anchored in place in the flange of the second shut-off valve housing 24.

Each hydraulic nut 34 engages the protruding portion of the corresponding solid stud 32 so as to secure the shut-off valve housings 22, 24 together. More specifically, the inner nut portion 38 of each hydraulic nut 34 is arranged to enclose the protruding portion of a respective solid stud 32, and the outer nut portion 36 is moved to its first position in order to push the internally threaded wall of the threaded insert inwards to directly grip the corresponding solid stud 32, as shown in Figures 7 and 8.

Each driving assembly includes a biasing element in the form of a return spring member 52 that is arranged between the outer and inner nut portions 36, 38. More particularly, in the embodiment shown, the return spring member 52 sits inside a recess formed in the inner nut portion 38 such that one end of the return spring member 52 abuts a floor of the recess and the other end of the return spring member 52 pushes against the outer nut portion 36. In this manner, the return spring member is configured to apply a biasing force that tends to urge the outer nut portion 36 to its second position so as to disengage the inner nut portion 38 from the corresponding solid stud 32. Hence, the hydraulic pressure in the first hydraulic chamber 48 must be sufficiently high to overcome the biasing force so as to enable the outer nut portion 36 to move to its first position.

The inner nut portion 38 of each hydraulic nut 34 is dimensioned such that a gap is formed between a base of the inner nut portion 38 and a floor of the corresponding recess formed in the flange surface of the first shut-off valve housing 22. The gap defines a second hydraulic chamber 54 that is hydraulically connected to the port 50 of the corresponding inner nut portion 38. Hence, once the outer nut portion 36 reaches its first position, each hydraulic actuator goes on to increase a hydraulic pressure of the corresponding second hydraulic chamber 54 so that the corresponding inner nut portion 38 is pushed away from the flange surface in order to apply a tensioning force to the corresponding solid stud 32 that it is gripping.

In this manner the shut-off valve housings 22, 24 are secured to each other via each first fastening arrangement and each second fastening arrangement in a second mode of the pipeline coupling 20, and the inner nut portion 38 and solid stud 32 of each second fastening arrangement is locked in an axial direction by maintaining the hydraulic pressures in the first and second hydraulic chambers 48, 54.

Preferably, a thread profile 55 of the internally threaded wall of the threaded insert is shaped to prevent hang-up. In particular, in the event of partial engagement between the internally threaded wall and the solid stud 32, the tooth angle between the thread profile and the solid stud 32 is preferably defined to enable the internally threaded wall to clear the solid stud 32 in order to prevent hang-up.

Hence, to reconfigure the pipeline coupling 20 to switch from the first mode to the second mode, each hydraulic nut 34 is configured to engage the corresponding solid stud 32.

To reconfigure the pipeline coupling 20 to switch from the second mode to the first mode, each hydraulic nut 34 is configured to disengage from the corresponding solid stud 32. This is carried out by operating each hydraulic actuator to decrease the hydraulic pressure within the first hydraulic chamber 48. The decrease in hydraulic pressure means that the biasing force applied by the return spring member 52 forces the outer nut portion 36 to move to its second position so as to permit the profile of the corresponding solid stud 32 to push the internally threaded wall of the threaded insert outwards into the corresponding cavity 46. This in turn releases each solid stud 32 from the corresponding threaded insert and thereby permits the disengagement of each hydraulic nut 34 from the corresponding solid stud 32, as shown in Figures 10 and 11. Such operation of the actuation mechanism to disengage each hydraulic nut 34 from the corresponding solid stud 32 may be triggered either by manual operation of the actuation mechanism or by an automatic control/monitoring system.

Examples of each hydraulic nut 34 are described in GB 2373554 A and GB 2381774 A. It is envisaged that, in other embodiments of the invention, each hydraulic nut 34 may be replaced by a different type of hydraulic nut. It is further envisaged that, in still other embodiments of the invention, each hydraulic nut 34 may be replaced by a different type of nut (e.g. a pneumatic nut) that can be mechanically driven to disengage the nut from the corresponding solid stud 32, with the other features of the nut being adapted as necessary.

In the first mode of the coupling, the shut-off valve housings 22, 24 are secured to each other via each first fastening arrangement, while each second fastening arrangement is configured to disengage each hydraulic nut 34 from the corresponding solid stud 32. As shown in Figure 3, this permits automatic separation of the shut-off valve housings 22, 24 in response to the pipeline coupling 20 being exposed to a tensile load exceeding the predetermined allowable tensile load rating.

In the second mode of the coupling, the shut-off valve housings 22, 24 are secured to each other via each first fastening arrangement and each second fastening arrangement. This temporarily increases the tensile load capacity of the pipeline coupling 20 beyond the predetermined allowable tensile load rating, which is defined by the sum of the tensile load capacities of the first fastening arrangements. This thereby prevents premature release of the first fastening arrangements, thus preventing breakage of the first fastening arrangements, when the pipeline coupling 20 is exposed to a tensile load exceeding the predetermined allowable tensile load rating. The second mode of the pipeline coupling 20 may be desirable under certain circumstances, such as installation, maintenance, repair, servicing, and transport of the coupling which may generate tensile loads larger than the predetermined allowable tensile load rating. Also, the second mode of the pipeline coupling 20 can be beneficially utilised during reeling of an associated pipeline around a reel or unreeling of the associated pipeline from the reel, which can generate bending moments resulting in tensile loads beyond the predetermined allowable tensile load rating.

The provision of an actuation mechanism that is operable to engage each hydraulic nut 34 with the corresponding solid stud 32 allows selective reconfiguration of the pipeline coupling 20 to the second mode in circumstances where it is desirable to increase the overall tensile load capacity of the pipeline coupling 20 above the predetermined allowable tensile load rating.

It is envisaged that the actuation mechanism could be operated remotely from a ship or shore-based control room. It is also envisaged that each hydraulic actuator may include a stab plate or a tail hose to enable remote operation of the actuation mechanism. The actuation mechanism could, for example, be operated when personnel and/or sensors determine that installation, maintenance, repair, servicing or transport of the pipeline coupling 20 is required or has been completed.

It is also envisaged that the actuation mechanism could be operated locally, e.g. by using a local control unit in the vicinity of the actuation mechanism. The local control unit may include a hydraulic power unit (or a pneumatic power unit if pneumatic nuts are employed). The local control unit may be sized to be portable, e.g. like a briefcase, so that it can be easily carried by a human operator.

In addition, the provision of the actuation mechanism to aid in the engagement and disengagement of the second fastening arrangements is particularly beneficial when it is difficult to access each second fastening arrangement, e.g. due to the location of the pipeline coupling 20 along the pipeline.

The ability to remotely operate each driving assembly to mechanically drive each hydraulic nut 34 improves safety and reduces operational time by removing the need for personnel to directly access the hydraulic nuts 34, obviates the costs of providing and operating additional infrastructure and equipment required to directly access the hydraulic nuts 34.

Also, the pipeline coupling 20 reduces operational time by enabling operation of each driving assembly to mechanically drive multiple hydraulic nuts 34 at the same time, for example, by linking the control of the driving assemblies electronically or hydraulically. Furthermore, the second fastening arrangements can be retrofitted to existing couplings that comprise the first fastening arrangements to secure their coupling sections together.

In the embodiment of Figure 1, the shut-off valve arrangement is referred to by the applicant as a FLIP-FLAP' valve arrangement, examples of which are described in EP 2 000 730 A2. It is envisaged that, in other embodiments of the invention, the shut-off valve arrangement may be replaced by other shut-off valve arrangements, including a valve arrangement referred to by the applicant as a PETAL VALVETM arrangement (such as described in EP 0 006 278 Al and GB 2051993 A) and a sleeve-based valve arrangement (such as described in GB 2391051 A).

In embodiments of the invention, one of the first and second shut-off valve housings 22, 24 may be the upstream shut-off valve housing, and the other of the first and second shutoff valve housings 22, 24 may be the downstream shut-off valve housing.

In other embodiments of the invention, it is envisaged that each longitudinal fastening member 28, 32 may be in the form of a bolt or pin instead of a stud, and/or each longitudinal fastening member 28, 32 may be threaded or unthreaded. Each longitudinal fastening member 28, 32 may instead be any one of: a barbed longitudinal fastening member 56; a top hat longitudinal fastening member 58; a longitudinal fastening member with a circumferential shoulder formed thereon 60; a longitudinal fastening member with a circumferential cut-out section formed therein 62; a longitudinal fastening member with a circumferential groove formed thereon 64; a longitudinal fastening member with a circumferential tapered section formed thereon 66; or a longitudinal fastening member with a circumferential scalloped section formed thereon 6, as shown in Figure 12.

In still other embodiments of the invention, it is envisaged that the pipeline coupling may include only one of the shut-off valves, with the single shut-off valve being located in one of the shut-off valve housings 22, 24. In such embodiments, a separate mechanism may be used to oppose the movement of the shut-off valve member 26 of the single shut-off valve in order to maintain the shut-off valve member 26 in its valve open position when the shut-off valve housings 22,24 are secured to each other.

It will be appreciated that the invention may include any number of first fastening arrangements and any number of second fastening arrangements, as long as the invention includes at least one first fastening arrangement and at least one second fastening arrangement.

Claims

CLAIMS1. A coupling, for releasably connecting two objects together, comprising: first and second coupling sections; at least one first fastening arrangement for securing the coupling sections to each other; at least one second fastening arrangement for securing the coupling sections to each other; and an actuation mechanism operably coupled with the or each second fastening arrangement, wherein the or each second fastening arrangement includes a longitudinal fastening member and a fastening nut, the or each fastening nut configured to be engageable with the corresponding longitudinal fastening member to secure the coupling sections to each other, the or each fastening nut configured to be disengageable from the corresponding longitudinal fastening member, wherein the actuation mechanism includes a or a respective driving assembly configured to, in use, mechanically drive the or each fastening nut so as to: engage the or each fastening nut with the corresponding longitudinal fastening member; and/or disengage the or each fastening nut from the corresponding longitudinal fastening member, wherein the coupling has a predetermined allowable tensile load rating that is defined by the or each first fastening arrangement securing the coupling sections to each other and the or each second fastening arrangement configured to disengage the or each fastening nut from the corresponding longitudinal fastening member, the or each first fastening arrangement configured to be releasable to cause separation of the coupling sections upon exposure of the coupling to a tensile load exceeding the predetermined allowable tensile load rating, and wherein configuration of the first and second fastening arrangements to secure the coupling sections to each other inhibits release of the or each first fastening arrangement when the coupling is exposed to a tensile load exceeding the predetermined allowable tensile load rating.
2. A coupling according to Claim 1 wherein the or each first fastening arrangement includes a weakened portion that breaks on exposure of the coupling to a tensile load exceeding the predetermined allowable tensile load rating.
3. A coupling according to any one of the preceding claims wherein the or each fastening nut includes outer and inner nut portions, the outer nut portion enclosing the inner nut portion and including an inner face with a cavity formed therein, the outer nut portion configured to be movable between first and second positions to alter the position of the cavity relative to the inner nut portion, wherein the inner face of the outer nut portion is configured to push the inner nut portion inwards to grip the corresponding longitudinal fastening member when the outer nut portion is in its first position, and the cavity formed in the inner face is positioned to permit outward expansion of the inner nut portion into the cavity when the outer nut portion is in its second position, and wherein the or each driving assembly is configured to, in use, mechanically drive the corresponding outer nut portion to move between its first and second positions.
4. A coupling according to any one of the preceding claims wherein the or each fastening nut is a hydraulic or pneumatic nut, and the or each driving assembly includes a hydraulic or pneumatic actuator configured to, in use, control a hydraulic or pneumatic pressure of the or each fastening nut.
5. A coupling according to Claim 4 wherein the hydraulic or pneumatic actuator of the or each driving assembly is configured to, in use, control a hydraulic or pneumatic pressure of the or each fastening nut to mechanically drive the or each fastening nut so as to: engage the or each fastening nut with the corresponding longitudinal fastening member; and/or disengage the or each fastening nut from the corresponding longitudinal fastening member.
6. A coupling according to Claim 4 or Claim 5 when dependent on Claim 3 wherein the or each fastening nut includes a first chamber hydraulically or pneumatically connected to the hydraulic or pneumatic actuator of the or the respective driving assembly, the first chamber of the or each fastening nut arranged so that, in use, a hydraulic or pneumatic pressure in the first chamber is controllable to drive the corresponding outer nut portion to move between its first and second positions.
7. A coupling according to Claim 6 wherein the hydraulic or pneumatic actuator of the or each driving assembly is configured to, in use, increase the hydraulic or pneumatic pressure in the first chamber of the or the respective fastening nut to cause the corresponding outer nut portion to move to its first position.
8. A coupling according to Claim 6 or Claim 7 wherein the hydraulic or pneumatic actuator of the or each driving assembly is configured to, in use, decrease the hydraulic or pneumatic pressure in the first chamber of the or the respective fastening nut to permit the corresponding outer nut portion to move to its second position.
9. A coupling according to any one of the preceding claims wherein the or each driving assembly includes a biasing element configured to apply a biasing force that tends to urge the or each fastening nut so as to disengage the or each fastening nut from the corresponding longitudinal fastening member.
10. A coupling according to Claim 9 wherein the or each driving assembly is configured to, in use, mechanically drive the or each fastening nut by applying a driving force that overcomes the biasing force so as to engage the or each fastening nut with the corresponding longitudinal fastening member.
11. A coupling according to Claim 9 or Claim 10 wherein the biasing element is or includes a resilient member.
12. A coupling according to any one of the preceding claims wherein the or each driving assembly is configured to, in use, mechanically drive the or each fastening nut so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.
13. A coupling according to Claim 12 when dependent from Claim 3 wherein the or each driving assembly is configured to, in use, mechanically drive the corresponding inner nut portion so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.
14. A coupling according to Claim 12 or Claim 13 when dependent from Claim 4 wherein the or each hydraulic or pneumatic actuator is configured to, in use, control a hydraulic or pneumatic pressure of the or each fastening nut to mechanically drive the or each fastening nut so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.
15. A coupling according to Claims 13 and 14 wherein the or each second fastening arrangement includes a second chamber hydraulically or pneumatically connected to the hydraulic or pneumatic actuator of the or the respective driving assembly, the second chamber of the or each fastening nut arranged so that, in use, a hydraulic or pneumatic pressure in the second chamber is controllable to mechanically drive the inner nut portion so as to apply a tensioning force to the corresponding longitudinal fastening member when the or each fastening nut is engaged with the corresponding longitudinal fastening member.
16. A coupling according to Claim 15 when dependent from any one of Claims 6 to 8 wherein the first and second chambers are connected to a common port that is hydraulically or pneumatically connected to the hydraulic or pneumatic actuator.
17. A coupling according to any one of the preceding claims wherein the coupling includes a plurality of second fastening arrangements, and the or each driving assembly is configured to, in use, simultaneously mechanically drive the fastening nuts.
18. A coupling according to any one of the preceding claims wherein each coupling section is or includes a flange, the or each first fastening arrangement is for securing the flanges of the coupling sections to each other, and the or each second fastening arrangement is for securing the flanges of the coupling sections to each other.
19. A coupling according to any one of the preceding claims, wherein the coupling is a pipeline coupling, and each coupling section is a pipeline section.
20. A coupling according to Claim 19 wherein the pipeline sections define a hollow bore along which flowable material may flow, at least one shut-off valve located within the hollow bore, the or each shut-off valve including a valve member movable between a valve open position and a valve closed position in which the valve member shuts off the flow of a flowable material through the hollow bore, the or each valve member being biased to move to its valve closed position on separation of the pipeline sections.
21. A coupling according to Claim 20 including a respective shut-off valve located within the hollow bore of each pipeline section, each shut-off valve including a valve member movable between a valve open position and a valve closed position in which the valve member shuts off the flow of a flowable material through the hollow bore, each valve member being biased to move to its valve closed position on separation of the pipeline sections.
22. Use of a coupling as a breakaway coupling or a release coupling, wherein the coupling is in accordance with Claim 20 or Claim 21.
23. A method of using a coupling in accordance with any one of Claims 1 to 21, the method comprising the step of operating the or each driving assembly to reconfigure the coupling between first and second modes, wherein the first mode of the coupling includes configuration of the or each first fastening arrangement to secure the coupling sections to each other, and configuration of the or each second fastening arrangement to disengage the or each fastening nut from the corresponding longitudinal fastening member, and wherein the second mode of the coupling includes configuration of the first and second fastening arrangements to secure the coupling sections to each other.
24. A method according to Claim 23 including the step of configuring the coupling in the second mode during installation, maintenance, repair, servicing, or transport of the to coupling.
25. A method according to Claim 23 or Claim 24 when dependent from Claim 20 or Claim 21, the method including the step of configuring the coupling in the first mode to use the coupling as a breakaway coupling or a release coupling.