FIELD OF THE INVENTION

The present invention relates to a coupling for use in a fluid flow line.

BACKGROUND OF THE INVENTION

Transporting cryogenic fluids such as liquefied natural gas (LNG), liquid nitrogen, liquid oxygen and liquid argon from one vessel to another is extremely hazardous. It is important to ensure that couplings between the vessels are properly secured. The connecting parts of such couplings may need to be inter-connected quickly and in challenging conditions, for example in ship-to-ship transport.

The connecting parts of a coupling are often inter-connected to one another by means of a thread arrangement. It can be time consuming to correctly position the thread of each part for connection, i.e. considerable relative rotation of the coupling parts may be required. Once correctly positioned, there can be a need for further considerable relative rotation of parts in order to secure the coupling.

Cryogenic fluids are quickly heated upon exposure to the atmosphere, expanding rapidly as they move from the liquid to the gas phase, often by many times their volume in a very short period of time. This rapid expansion can cause an explosion. It is therefore desirable when coupling vessels together, e.g. for transferring cryogenic fluid from a tanker via a hose, to minimise the risk of any cryogenic fluid escaping.

There are a number of ways in which leakage at a coupling can occur. The connecting parts of the coupling may not be correctly located in relation to one another. It may be possible to open a coupling valve arrangement despite incorrect location of the parts of a coupling, which can lead to significant leakage.

The connecting parts of a coupling may have profiles in which fluid can collect during transport, so that the fluid can then expand and explode when exposed to the atmosphere on disconnection of the coupling.

Disconnection of the connecting parts of a coupling whilst a coupling valve arrangement is open must be avoided, as it could lead to extensive leakage.

Similar-looking couplings may be used for liquid transport and gas transport, which can lead to confusion. Users may attempt to connect a gas flow line with a liquid flow line, and vice versa. The present invention seeks to provide improvements to address one or more problems or disadvantages of the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided a coupling for use in a fluid flow line, the coupling comprising first and second parts connectable to define a fluid flow path. The first part defines an internal thread, and the second part defines an external thread. The threads are configured to cooperate with one another in order to secure the first and second parts to one another. Each of the internal thread and the external thread comprises two or more portions each having a thread start, thereby defining a multi-start thread. Advantageously, where the internal and external threads both comprise multi-start threads, the first and second parts can be fully secured to one another without the need for greater than 180° rotation of the first and second parts relative to one another, increasing the ease and speed of connection.

The coupling may comprise at least a first portion having a first thread start and a second portion having a second thread start. The first and second thread starts of the internal thread may be located substantially 180° from one other, and the first and second thread starts of the external thread may be located substantially 180° from one another.

The location of the thread starts at 180° from one another allows the first and second parts to be secured to one another with little relative rotation between the two, e.g. 5° rotation between the two.

The external thread may comprise a first portion, and a second portion separate from the first portion. Each of the first portion and the second portion may extend only 180° or less about a circumference of the second part.

Each of the first portion and the second portion may extend 90° or less about a circumference of the second part.

Each of the first portion and the second portion may extend 30° or less about a circumference of the second part.

Thread portions of such lengths provide sufficient overlap of external and internal threads to ensure a secure connection between the first and second parts, whilst simplifying manufacture of the external thread.

The coupling may comprise a sleeve comprising the internal thread, the sleeve being movable between an open position, in which the first and second parts are detachable from one another, and a closed position, in which the first and second parts are secured to one another.

The first part may comprise a blocking mechanism having an active state, in which movement of the sleeve to the closed position is prevented, and an inactive state, in which movement of the sleeve to the closed position is permitted.

The second part may be configured to deactivate the blocking mechanism when the first and second parts are located for connection to one another.

Advantageously, the sleeve is prevented from being moved to a closed position until the first and second parts are properly located for connection. The coupling cannot therefore be assembled without proper location of the first and second parts, and an indication is given to the operator if proper location of the first and second parts has not taken place.

The coupling may be configured to activate the blocking mechanism, during disconnection of the coupling, to prevent movement of the sleeve from the open position to the closed position.

The coupling may be configured to drive the activation of the blocking mechanism during disconnection of the first and second parts.

The coupling may be configured to deactivate the blocking mechanism, during connection of the first and second parts, to enable movement of the sleeve from the open position to the closed position.

The first part may comprise a cavity. The blocking mechanism may be provided in the cavity. The second part may comprise a protruding member configured to extend into the cavity and engage the blocking mechanism, during disconnection of the first and second parts.

The protruding member may drive the activation of the blocking mechanism, during disconnection of the first and second parts.

The protruding member may drive the deactivation of the blocking mechanism, during connection of the first and second parts.

The blocking mechanism may comprise a blocking member. The sleeve may define a recess located such that, when the blocking mechanism is activated, a portion of the blocking member is located in the recess to prevent movement of the sleeve.

The protruding member may drive the blocking member into the recess, during disconnection of the first and second parts.

The protruding member may drive the blocking member out of the recess, during connection of the first and second parts.

The blocking member may comprise a hook portion and the protruding member may comprise an aperture therethrough. The hook portion may be configured to extend into said aperture to engage the protruding member during disconnection of the first and second parts.

The first part may comprise a first face, and the second part may comprise a second face configured to abut the first face when the first and second parts are located for connection to one another. In use, when the second face abuts the first face the blocking mechanism may be deactivated.

This arrangement provides a simple and effective means of ensuring that the sleeve is prevented from being moved to a closed position until the first and second parts are properly located, i.e. with the first and second faces abutting.

The blocking mechanism may comprise a control member. The control member may be movable between an active position, in which the blocking mechanism is activated, and an inactive position, in which the blocking mechanism is deactivated. The second part may be configured to move the control member to the inactive position when the first and second parts are located for connection. The second face me be configured to move the control to the inactive position when the first and second parts are located for connection.

The control member may be resiliently biased towards the active position.

The control member provides a simple and effective mechanism by which the blocking mechanism can be deactivated by the second part.

The blocking mechanism may comprise a blocking member configured to prevent movement of the sleeve to the closed position when the blocking mechanism is in the active state. The blocking member may be spherical.

The control member may be configured to retain the blocking member in the path of the sleeve when the control member is in the active position. The control member may be configured to allow the blocking member to be moved out of the path of the sleeve when the control member is in the inactive position.

The sleeve may be rotatable between the open position and the closed position.

The coupling may comprise a handle, and a valve arrangement configured for actuation by the handle. The handle may be prevented from actuating the valve to an open position unless the sleeve is in the closed position. The sleeve may define a recess located such that, when the sleeve is in the closed position, the recess enables movement of the actuating member to actuate the valve to an open position.

This arrangement prevents opening of the valve unless the first and second parts are properly located for connection, thus avoiding leakage and fluid loss.

The first part may comprise a first face having a first half and a second half, wherein the blocking mechanism is located at the second half. In use, the second half may be positioned below the first half.

Location of the blocking mechanism at a lower half of the first face reduces the likelihood of any water collecting at the blocking mechanism and freezing, so inhibiting function of the blocking mechanism.

The first part may comprise two or more blocking mechanisms.

The first part may comprise a first valve head, and the second part may comprise a second valve head configured to abut the first valve head when the first and second parts are located for connection to one another.

The second valve head may define a recess.

A protrusion may extend from the second valve head and may be configured to extend into the recess when the first and second parts are connected.

The protrusion extending into the recess limits product loss during disconnection by limiting the amount of fluid held within the recess prior to disconnection.

The protrusion may extend substantially the full depth of the recess.

The protrusion extending substantially the full depth of the recess further limits the amount of fluid held within the recess prior to disconnection, and so further limits product loss during disconnection.

The recess may be configured to receive a tool for use in securing a first component of the second part to a second component of the second part.

The recess may be substantially hexagonal in profile.

The protrusion may be substantially circular in profile.

A free end of the protrusion distal the second valve head may define a chamfer.

There is also provided a coupling for use in a fluid flow line, the coupling comprising first and second parts connectable to define a fluid flow path, and a sleeve configured to secure the first and second parts in relation to one other, the sleeve being movable between an open position where the first and second parts are detachable from one another, and a closed position where the first and second parts are secured to one another. The first part comprises a blocking mechanism having an active state where movement of the sleeve to the closed position is prevented, and an inactive state where movement of the sleeve to the closed position is permitted. The second part is configured to deactivate the blocking mechanism when the first and second parts are located for connection to one another.

Advantageously, the sleeve is prevented from being moved to a closed position until the first and second parts are properly located for connection. The coupling cannot therefore be assembled without proper location of the first and second parts, and an indication is given to the operator if proper location of the first and second parts has not taken place.

The first part may comprise a first face, and the second part may comprise a second face configured to abut the first face when the first and second parts are located for connection to one another.

The second part may be configured to deactivate the blocking mechanism when the second face abuts the first face. The second face may be configured to deactivate the blocking mechanism. In use, when the second face abuts the first face the blocking mechanism may be deactivated.

This arrangement provides a simple and effective means of ensuring that the sleeve is prevented from being moved to a closed position until the first and second parts are properly located, i.e. with the first and second faces abutting.

The blocking mechanism may comprise a control member, wherein the control member is movable between an active position, where the blocking mechanism is activated, and an inactive position, where the blocking mechanism is deactivated. The second part is configured to move the control member to the inactive position when the first and second parts are located for connection.

The control member may be resiliently biased towards the active position.

The control member provides a simple and effective mechanism by which the blocking mechanism can be deactivated by the second part.

The blocking mechanism may comprise a blocking member configured to prevent movement of the sleeve to the closed position when the blocking mechanism is in the active state. The blocking member may be spherical.

The control member may be configured to retain the blocking member in the path of the sleeve when the control member is in the active position. The control member may be configured to allow the blocking member to be moved out of the path of the sleeve when the control member is in the inactive position.

The sleeve may be rotatable between the open position and the closed position.

The sleeve may be connected to one or other of the first and second parts. The sleeve may define an internal thread configured to receive an external thread defined by the other of the first and second parts.

The first part may comprise a first face, wherein the first part may comprise two or more blocking mechanisms, and/or the blocking mechanism may be located at a lower half of the first face.

Location of the blocking mechanism at a lower half of the first face reduces the likelihood of any water collecting at the blocking mechanism and freezing, so inhibiting function of the blocking mechanism.

The first part may comprise two or more blocking mechanisms.

The coupling may be configured to activate the blocking mechanism, during disconnection of the coupling, to prevent movement of the sleeve from the open position to the closed position.

The coupling may be configured to drive the activation of the blocking mechanism during disconnection of the first and second parts.

The coupling may be configured to deactivate the blocking mechanism, during connection of the first and second parts, to enable movement of the sleeve from the open position to the closed position.

The first part may comprise a cavity. The blocking mechanism may be provided in the cavity. The second part may comprise a protruding member configured to extend into the cavity and engage the blocking mechanism, during disconnection of the first and second parts.

The protruding member may drive the activation of the blocking mechanism, during disconnection of the first and second parts.

The protruding member may drive the deactivation of the blocking mechanism, during connection of the first and second parts.

The blocking mechanism may comprise a blocking member. The sleeve may define a recess located such that, when the blocking mechanism is activated, a portion of the blocking member is located in the recess to prevent movement of the sleeve.

The protruding member may drive the blocking member into the recess, during disconnection of the first and second parts.

The protruding member may drive the blocking member out of the recess, during connection of the first and second parts.

The blocking member may comprise a hook portion and the protruding member may comprise an aperture therethrough. The hook portion may be configured to extend into said aperture to engage the protruding member during disconnection of the first and second parts.

There is further provided a coupling for use in a fluid flow line, the coupling comprising first and second parts connectable to define a fluid flow path. The first part comprises a first valve head, and the second part comprises a second valve head configured to abut the first valve head when the first and second parts are located for connection to one another. The second valve head defines a recess. A protrusion extends from the second valve head and is configured to extend into the recess when the first and second parts are connected.

The protrusion extending into the recess limits product loss during disconnection by limiting the amount of fluid held within the recess prior to disconnection.

The protrusion may extend substantially the full depth of the recess.

The protrusion extending substantially the full depth of the recess further limits the amount of fluid held within the recess prior to disconnection, and so further limits product loss during disconnection.

The recess may be configured to receive a tool for use in securing a first component of the second part to a second component of the second part.

The recess may be substantially hexagonal in profile. The protrusion may be substantially circular in profile. A free end of the protrusion distal the second valve head may define a chamfer.

There is yet further provided a coupling for use in a fluid flow line, the coupling comprising first and second parts connectable to define a fluid flow path, a sleeve configured to secure the first and second parts in relation to one other, the sleeve being movable between an open position where the first and second parts are detachable from one another, and a closed position where the first and second parts are secured to one another a handle and a valve arrangement configured for actuation by the handle. The handle is prevented from actuating the valve to an open position unless the sleeve is in the closed position.

This arrangement prevents opening of the valve unless the sleeve is in the closed position and the first and second parts are secured to one another, thus avoiding leakage.

The sleeve may define a recess located such that, when the sleeve is in the closed position, the recess enables movement of the handle to actuate the valve to an open position.

The handle may be a lever, and a free end of the lever may be aligned with the recess when the sleeve is in the closed position.

The coupling may further comprise a latch member movable between an extended position and a depressed position. The latch member may be configured to prevent movement of the sleeve from the closed position when in the extended position. The handle may be configured for depressing the latch member.

The handle may be configured for depressing the latch member only when the sleeve is in the closed position.

This arrangement prevents movement of the sleeve from the closed position when the valve is open, thus preventing inadvertent opening of the valve.

The latch member may be resiliently biased towards the extended position.

The latch member is therefore automatically returned to the extended position.

The latch member may comprise a resilient biasing member configured to resiliently bias the latch member towards the extended position, and a seal configured to prevent fluid ingress to the resilient biasing member.

The resilient biasing member is thus protected from the ingress of fluid that could freeze, disabling the latch member.

There is also provided a coupling for use in a fluid flow line, the coupling comprising : first and second parts, wherein the coupling has a first condition in which the first and second parts are connected to one another to define a fluid flow path, and a second condition in which the first and second parts are disconnected from one another; a sleeve configured to secure the first and second parts in relation to one another, wherein, when the coupling is in the first condition, the sleeve is movable between an open position in which the coupling is able to transition from the first condition to the second condition, and a closed position in which transition of the coupling from the first condition to the second condition is prevented; and a blocking mechanism for preventing movement of the sleeve; wherein the coupling is configured to activate the blocking mechanism, during transition of the coupling from the first condition to the second condition, to prevent movement of the sleeve from the open position to the closed position.

Due to the temperatures experienced in transferring cryogenic fluids, the blocking mechanism can become frozen in place. The arrangement of the present embodiment ensures that the blocking mechanism is driven back into the active state during the disconnection of the first and second parts.

In exemplary embodiments, there is provided a coupling for use in a fluid flow line, the coupling comprising :

first and second parts, wherein the coupling has a first condition in which the first and second parts are connected to one another to define a fluid flow path therebetween, and a second condition in which the first and second parts are disconnected from one another;

a sleeve configured to secure the first and second parts in relation to one another when the coupling is in the first condition, wherein, when the coupling is in the first condition, the sleeve is movable between an open position in which the first and second parts can be separated, and a closed position in which separation of the first and second parts is prevented; and

a blocking mechanism for preventing movement of the sleeve;

wherein the coupling is configured to activate the blocking mechanism, from an inactive position to an active position, when the sleeve is in the open position, during transition of the coupling from the first condition to the second condition, in order to prevent movement of the sleeve from the open position to the closed position.

The coupling is advantageous, since the blocking member is operable to prevent movement of the sleeve to the closed position when the first and second parts are disconnected. Hence, the sleeve will always be in the open position prior to a connection operation of the first and second parts. This provides for efficient and safe connection operations.

The coupling may be configured to drive the activation of the blocking mechanism during transition of the coupling from the first condition to the second condition.

Advantageously, this arrangement ensures that the blocking mechanism is positioned in the active state when the first and second parts are disconnected.

The second part may engage the blocking mechanism to drive activation of the blocking mechanism, during transition of the coupling from the first condition to the second condition. The coupling may be configured to deactivate the blocking mechanism, during transition of the coupling from the second condition to the first condition, to enable movement of the sleeve from the open position to the closed position.

The second part may engage the blocking mechanism to drive the deactivation of the blocking mechanism, during transition of the coupling from the second condition to the first condition.

The first part may comprise a cavity. The blocking mechanism may be provided in the cavity. The second part may comprise a protruding member configured to extend into the cavity and engage the blocking mechanism, during transition of the coupling from the second condition to the first condition.

The protruding member may drive the activation of the blocking mechanism, during transition of the coupling from the first condition to the second condition.

The protruding member may drive the deactivation of the blocking mechanism, during transition of the coupling from the second condition to the first condition.

The blocking mechanism may comprise a blocking member. The sleeve may define a recess located such that, when the blocking mechanism is activated, a portion of the blocking member is located in the recess to prevent movement of the sleeve.

The protruding member may drive the blocking member into the recess, during transition of the coupling from the first condition to the second condition.

The protruding member may drive the blocking member out of the recess, during transition of the coupling from the second condition to the first condition.

The blocking member may comprise a hook portion and the protruding member may comprise an aperture therethrough. The hook portion may be configured to extend into said aperture to engage the protruding member, during transition of the coupling from the second condition to the first condition.

The first part may comprise a first face, and the second part may comprise a second face configured to abut the first face, when the coupling is in the first condition.

The first part may comprise a cavity housing the blocking mechanism therein, and the second part may comprise a protruding member configured to extend into the cavity and engage the blocking mechanism, during transition of the coupling from the second condition to the first condition. The cavity may be provided on the first face and the protruding member extends from the second face. There is also provided a kit comprising a pair of couplings as described above wherein a first coupling comprises a first part defining an internal right-hand thread, and a second coupling comprises a first part defining an internal left-hand thread.

Confusion between gas and liquid lines is avoided with the use of different threads, so that a gas first part cannot be connected to a liquid second part, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of first and second parts of a coupling, prior to connection;

Figure 2 is a perspective view of the coupling of the embodiment of Figure 1, with the first and second parts connected to one another, prior to securement;

Figure 3 is a perspective view of the coupling of the embodiment of Figures 1 and 2, with the first and second parts secured to one another;

Figure 4 is a partial perspective view of the first part of the coupling of the embodiment of Figures 1 to 3, showing a blocking mechanism;

Figure 5a is a partial cross-sectional view through the blocking mechanism of the embodiment of Figure 4 in an active state;

Figure 5b is an alternative cross-sectional view through the blocking mechanism of the embodiment of Figure 5a;

Figure 6a is a partial cross-sectional view through the blocking mechanism of the embodiment of Figure 4 in an inactive state;

Figure 6b is an alternative cross-sectional view through the blocking mechanism of the embodiment of Figure 6a;

Figure 7 is a plan view of the first part of the coupling of the embodiment of Figures 1 to 6b;

Figure 8 is a cross-sectional view through the coupling of the embodiment of Figures 1 to

7;

Figure 8a is partial view of area C of Figure 8;

Figure 8b is a partial cross-sectional view through the coupling of the embodiment of Figures 8 and 8a; Figure 9a is a partial perspective view of the first part of the coupling of the embodiment of Figures 1 to 8b;

Figure 9b is a perspective view of the second part of the coupling of the embodiment of Figures 1 to 9a;

Figure 10 is a cross-sectional view through the coupling of the embodiment of Figures 1 to 9b, with a valve arrangement in a closed position;

Figure 11 is a cross-sectional view through the coupling of the embodiment of Figures 1 to 10, with the valve arrangement in an open position;

Figure 12 is a perspective view of the coupling of the embodiment of Figures 1 to 11, with a valve actuation handle in an open position;

Figure 13 is a perspective view of the first part of the coupling of the embodiment of Figures 1 to 12, with the first and second parts secured to one another and the valve actuation handle in a closed position;

Figure 13a is an enlarged partial view of the valve actuation handle of Figure 13;

Figure 14 is a partial perspective view of a sleeve of the embodiment of Figures 1 to 13a;

Figure 15 is a cross-sectional view through a button of the embodiment of Figures 1 to 14;

Figure 16 a perspective view of first and second parts of a coupling, prior to connection;

Figure 17 an alternative perspective view of first and second parts of the coupling of Figure 16, prior to connection;

Figure 18 a cross-sectional view through the coupling of Figure 16, prior to connection;

Figure 19 a partial perspective view of the sleeve and blocking member of Figure 18, with the blocking member in the active position;

Figure 20 a cross-sectional view through the coupling of Figure 16, with the first and second parts secured to one another; and

Figure 21 a partial perspective view of the sleeve and blocking member of Figure 20, with the blocking member in the inactive position.

DETAILED DESCRIPTION OF EMBODIMENT(S)

With reference to Figures 1 to 3, a coupling for use in a fluid flow line is indicated generally at 10. The coupling 10 has first 12 and second 14 parts that are connectable to one another to define a fluid flow path. In this embodiment, the coupling 10 is configured for use as a quick connect/quick disconnect drybreak coupling, for example for use in loading and unloading cryogenic liquefied gases. For example, the coupling 10 may be used for small- scale LNG transfer to road or rail tankers, or for LNG bunkering.

In alternative embodiments, the coupling is configured for transporting some alternative fluid. "Fluid" is used throughout the specification to refer to liquid or gas.

The first 12 and second 14 parts are configured to be fixed together in order to create a secure fluid flow path. A sleeve 16 is configured to secure the first 12 and second 14 parts to one another. The sleeve 16 is movable between an open position where the first 12 and second 14 parts are detachable from one another (as shown in Figures 1 and 2), and a closed position, where the first 12 and second 14 parts are secured to one another (as shown in Figure 3).

The first part 12 has a blocking mechanism 18. The blocking mechanism 18 is intended to prevent movement of the sleeve 16 to the closed position shown in Figure 3 when the first 12 and second 14 parts are not properly located for connection to one another.

The blocking mechanism 18 has an active state, shown in Figure 1, where movement of the sleeve 16 to the closed position is prevented, and an inactive state (discussed in further detail below) where movement of the sleeve to the closed position is permitted. Deactivation of the blocking mechanism 18 is effected by the second part 14, when the first 12 and second 14 parts are properly located for connection to one another. In this way, movement of the sleeve 16 to the closed position is prevented unless the first 12 and second 14 parts are correctly located for connection to one another. That is, the first 12 and second 14 parts cannot be secured together unless the first 12 and second 14 parts are properly located with respect to one another. An operator of the coupling 10 will become aware of incorrect location of the first 12 and second 14 parts due to the inability to move the sleeve 16 from the open position to the closed position, and so can then correct the location of the first 12 and second 14 parts.

The first part 12 has a first face 20, and the second part 14 has a second face 22. The first 20 and second 22 faces are configured to abut one another when the first 12 and second 14 parts are correctly located for connection to one another. That is, the first 20 and second 22 faces are in contact with one another, without pockets or recesses in which fluid could collect. Abutment of the first 20 and second 22 faces limits the collection of fluid between the first 12 and second 14 parts, so limiting leakage on disconnection of the coupling 10.

In this embodiment, the second part 14 is configured to deactivate the blocking mechanism 18 when the second face 22 abuts the first face 20. This arrangement ensures that deactivation of the blocking mechanism 18 cannot take place unless the first 20 and second 22 faces abut one another, i.e. unless the first 12 and second 14 parts are correctly located for connection.

In alternative embodiments, another feature of the second part is configured to effect deactivation of the blocking mechanism when the first and second parts are correctly located for connection to one another.

In this embodiment, the sleeve 16 is rotatable between the open and closed positions about a longitudinal axis A-A of the sleeve 16. The sleeve 16 defines an internal thread 17. The internal thread 17 is configured to receive a corresponding external thread 19 defined by the second part 14, in order to secure the first 12 and second 14 parts to one another. The sleeve 16 is rotatably keyed to the first part 12, i.e. so that sleeve 16 is rotatable about a longitudinal axis A-A of the first part 12, but is axially located. The sleeve 16 includes an opposing pair of handles 21, which allow the sleeve to be easily grasped and rotated.

The blocking mechanism 18 is shown in further detail in Figures 4, 5a, 5b, 6a and 6b. Figures 4, 5a and 5b show the blocking mechanism 18 in its active state. The blocking mechanism 18 of this embodiment has a control member 24 for controlling activation and deactivation of the blocking mechanism 18. The control member 24 is movable between an active position, as shown in Figures 4, 5a and 5b, and an inactive position, as shown in Figures 6a and 6b. The control member 24 of this embodiment is supported in a cavity 25 defined by the first part 12.

When the control member 24 is in the active position, the blocking mechanism 18 is in its active state, so that movement of the sleeve 16 to the closed position is prevented. When the control member 24 is in the inactive position, the blocking mechanism 18 is in its inactive state, so that movement of the sleeve 16 to the closed position is possible. The control member 24 is moved from the active position to the inactive position by the second part 14, when the first 12 and second 14 parts are correctly located for connection.

The blocking mechanism 18 includes a resilient biasing member 26. In this embodiment, the resilient biasing member is a compression spring 26. The spring 26 is arranged to resiliently bias the control member 24 towards the active position, so that the control member 24 returns to the active position, and the blocking mechanism 18 returns to the active state, when the first 12 and second 14 parts are not located for connection to one another (i.e. are separated from one another). The spring 26 is located in the cavity 25, and is partly received within a void 27 defined by a first end 24a of the control member 24. A first end 26a of the spring 26 abuts an end 27a of the void 27. A second end (not shown) of the spring 26 abuts an internal feature of the first part 12. In this embodiment, the blocking mechanism 18 comprises a blocking member 28 that is configured to prevent movement of the sleeve 16 to the closed position when the blocking mechanism 18 is in the active state. The blocking member 28 lies in the path of the sleeve 16 when the blocking mechanism 18 is active, so that the sleeve 16 is prevented from movement to the closed position. The blocking member 28 is held in the path of the sleeve 16 by the control member 24. In this embodiment, the blocking member 28 is held partly in a recess 30 defined by the sleeve 16, and partly in the cavity 25, thus preventing rotation of the sleeve 16 to the closed position, when the blocking mechanism is in the active state.

In this embodiment, the control member 24 is moved between the active position and the inactive position along a longitudinal axis B-B. In this embodiment, the control member 24 is substantially circular in cross-section, and has a variable diameter along the longitudinal axis B-B. The control member 24 has a first, wider diameter x at the first end 24a, and a second, narrower diameter y at a second end 24b. When the control member 24 is in the active position, the blocking member 28 is held in the path of the sleeve 16 by the wider end 24a, as shown in Figures 5a and 5b.

In an alternative embodiment, the control member has some alternative suitable cross- section, e.g. polygonal, and/or may be variable in width along its length.

The second part 14 acts on the control member 24 when the first 12 and second 14 parts are located for connection to one another. In this embodiment, at least part of the second end 24b extends outwardly from the first face 20 when the control member 24 is in the active position. The second face 22 acts on the second end 24b as the first 12 and second 14 parts are moved into location for connection, moving the control member 24 along the axis B-B until it reaches the inactive position as the second face 22 abuts the first face 20.

As the control member 24 is moved to the inactive position by the second face 22, the wider end 24a is moved away from the blocking member 28, and the narrower end 24b is moved adjacent the blocking member 28. The blocking member 28 is therefore no longer held in the path of the sleeve 16, and can be moved towards the control member 24, into the cavity 25. In this embodiment, the blocking member 28 is spherical, and is moved out of the recess 30 and into the cavity 25 (and so out of the path of the sleeve 16) upon initial rotation of the sleeve 16 towards the closed position. The spherical shape of the blocking member 28 eases its movement out of the path of the sleeve 16.

In alternative embodiments, the blocking member is of another suitable shape, e.g. polygonal. In an alternative embodiment, the blocking member is resiliently biased out of the path of the sleeve by a resilient biasing member. In an alternative embodiment, the control member defines a recess configured to receive the blocking member, rather than having a wider end and a narrower end. The control member 24 of this embodiment has an angled shoulder 32 between the outer diameter of the wider 24a and narrower 24b ends. The shoulder 32 allows the blocking member 28 to gradually be moved out of the recess 30. In an alternative embodiment, the control member has no such shoulder, but is stepped between the wider and narrower ends. In an alternative embodiment, a shoulder of some alternative shape is provided, such as a curved shoulder.

The coupling 10 of this embodiment has two blocking mechanisms 18, as shown in Figure 7. The blocking mechanisms 18 of this embodiment are located either side of a centre line D-D of the first part 12, so that the blocking mechanisms 18 will be deactivated simultaneously when the first 12 and second 14 parts meet with an even load distribution.

In an alternative embodiment, the coupling has a single blocking mechanism. In one such embodiment, the blocking mechanism is located to the left hand side or to the right hand side of the centre line. In another embodiment, the blocking mechanism is centrally located. In alternative embodiments, the coupling has three or more blocking mechanisms.

Both blocking mechanisms 18 of this embodiment are located in the lower part of the first part 12 when the first part 12 is located for use. The location of the blocking mechanisms 18 in the lower part of the first part 12 reduces the likelihood of water ingress (e.g. due to rain), and so reduces the likelihood of freezing of the blocking mechanisms 18.

As shown in Figures 8, 8a and 8b, the internal thread 17 and the external thread 19 each comprise a multi-start thread. That is, each thread 17, 19 has two or more distinct protruding thread portions extending around the circumference of the respective first 12 or second 14 part. Each thread portion has a thread start configured for engagement with a thread start of a thread portion of the opposing part 12, 14.

In this embodiment, the internal thread 17 has two start points 17a, 17b located substantially 180° from one another around the internal circumference of the first part 12. The external thread 19 has two start points 19a, 19b located substantially 180° from one another around the internal circumference of the second part 14. In an alternative embodiment, the internal and external threads each have three or more thread portions, each with a thread start.

The provision of multiple start points on each thread enables the first 12 and second 14 parts to be secured to one another with less rotation than with a standard one-start thread. A standard one-start thread arrangement is commonly intended to go through more than 180° of relative rotation of parts to achieve a known secure connection, i.e. one where there is engagement of threads at opposing points of the circumference. The thread arrangement of this embodiment requires very little relative rotation in order to achieve a secure connection where there is engagement of threads at opposing points of the circumference. For example, 5° of rotation would ensure engagement of threads at opposing points of the circumference. In this embodiment, the sleeve 16 is configured for 90° of rotation from the open to the closed position. Secure connection of the first and second parts to one another is thus easier and less time-consuming.

In particular, the combination of the blocking mechanism and the two-start thread arrangement reduces the rotation needed between the first and second parts to knowingly achieve a secure connection - although only a small amount of rotation is required, the operator can be certain that a secure connection has been achieved, as the blocking mechanism would prevent any rotation at all should the first and second parts be incorrectly located.

As shown in Figure 8a, where the sleeve 16 is in the open position, the thread starts 17a, 17b, 19a, 19b are located on the respective circumference of the first 12 and second 14 parts to provide minimum rotation of the sleeve 16. The first 12 and second 14 parts of the coupling 10 are substantially self-orientating, as they are either fixed in position, or attached to a self-orientating hose - due to the thickness and rigidity of such hoses, it is difficult for an operator to rotate the first or second part out of the correct orientation. The thread starts 17a, 17b are located close to the thread starts 19a, 19b, to allow minimum relative rotation of the first 12 and second 14 parts, as indicated by arrow z in Figure 8a.

In this embodiment, the internal thread start 17a is located substantially 7° from the external thread start 19a, and the internal thread start 17b is located substantially 7° from the external thread start 19b. This location of the thread starts 17a, 17b, 19a, 19b allows the second part 14 to be correctly positioned in relation to the first part 12 on an initial joining of the first 12 and second 14 parts, so that the second face 22 abuts the first face 20 without substantial adjustment of the two parts.

In an alternative embodiment, each internal thread start is located between 3° and 10° from the respective external thread start.

In this embodiment, each thread portion 19c, 19d of the external thread 19 extends only partway around the circumference of the second part 14. In this embodiment, each thread portion 19c, 19d extends around substantially 30° of the second part 14 circumference. In an alternative embodiment, each thread portion of the external thread extends 180° or less around the second part circumference, or 90° or less around the second part circumference, or 45° or less around the second part circumference. These curtailed thread portions are simpler to manufacture than a thread portion extending more than 180° around the circumference, as there is no overlap between thread portions, allowing easy access to a tool. In addition, the curtailed thread portions advantageously reduce the mass of the coupling and reduce the amount of material used.

Referring now to Figures 9a, 9b, 10 and 11, the coupling 10 includes a valve arrangement 50 configured to control opening and closing of the fluid flow line. The first part 12 comprises a first valve head 52. The second part 14 comprises a second valve head 54 arranged to abut the first valve head 52 when the first 12 and second parts 14 are located for connection. The second valve head 54 of this embodiment is made up of an inner part 54a and an outer part 54b, configured for abutment with the first valve head 52. The inner part 54a defines an internal thread 55a configured to receive an external thread 55b. The inner 54a and outer 54b parts are held together by the internal 55a and external 55b threads. A central recess 56 defined by the outer part 54b is configured to receive a tool such as an alien key to assist fastening together of the inner 54a and outer 54b parts.

The first valve head 52 of this embodiment defines a protrusion 58 that extends from the first valve head 52 towards the second valve head 54, and is configured to extend into the recess 56 when the first 12 and second 14 parts are correctly located for connection, as shown in Figures 10 and 11. The protrusion 58 excludes fluid from the recess 56, and so reduces the likelihood of such fluid causing an explosion on disconnection of the coupling 10.

The protrusion 58 extends substantially the full depth of the recess 56, and is of a similar width, so that a substantial proportion of the volume of the recess 56 is filled by the protrusion 58. In this embodiment, the recess 56 is substantially hexagonal in profile. In this embodiment, the protrusion 58 is substantially circular in profile. In alternative embodiments, the recess and/or the protrusion is of some other suitable, compatible shape.

In this embodiment, a free end 58a of the protrusion 58 is chamfered, to improve location of the protrusion 58 within the recess 56. In alternative embodiments, the free end is not chamfered.

As shown in Figures 10, 11 and 12, the valve arrangement 50 is configured for actuation by an actuation member 60 controlled by a handle 62. The handle 62 of this embodiment is pivoted by an operator from a closed position (shown in Figure 10) to an open position (shown in Figure 12) to move the valve arrangement 50 from the closed position shown in Figure 10 to the open position shown in Figure 11. The handle 62 of this embodiment is connected to the actuation member 60 at a pivot point 61 in an over-centre arrangement. A free end 62a of the handle 62 extends beneath the sleeve 16 when the handle is in the closed position. As shown in Figure 2, when the sleeve 16 is in the open position, the sleeve 16 prevents the handle 62 from being moved to the handle open position. Advantageously, opening of the valve arrangement 50 is thus prevented whilst the sleeve is in the open position - and, due to the blocking mechanism, the sleeve 16 can only be moved to the closed position when the first 12 and second 14 parts are properly located for connection. The valve arrangement 50 cannot therefore be opened when the first 12 and second 14 parts are not properly connected.

The sleeve 16 defines a recess 64, e.g. a notch, configured to allow opening of the handle 62 (see Figures 12, 13, 13a and 14). The recess 64 is located such that, when the sleeve 16 is in the closed position, the recess 64 is positioned over the free end 62a of the handle 62. The free end 62a can be passed through the recess 64 by the operator, so that the handle 62 can be moved to the open position and the valve arrangement can be opened.

With reference to Figures 13, 13a, 14 and 15, movement of the sleeve 16 from the closed position whilst the valve arrangement 50 is open is prevented by a latch member or button 66. The latch member 66 is situated on the first part 12 in line with the recess 64 when the sleeve 16 is in the closed position. When the handle 62 is in the open position, the latch member 66 extends to a corresponding recess 68 defined by the sleeve 16. The sleeve 16 is therefore prevented from rotation to the open position.

In order for the sleeve 16 to be rotated to the open position, the latch member 66 must be depressed, so that there is clearance between the sleeve 16 and the latch member 66. In this embodiment, access to the latch member 66 is limited by the sleeve 16. For example, the latch member 66 cannot be depressed by hand by an operator due to the limited access - the recess 64 is configured to be too narrow for access by hand. In addition, the force required to depress the latch member 66 is such that it would be difficult to depress by hand. As the free end 62a of the handle 62 is configured to pass through the recess 64, the free end 62a can be used to depress the latch member 66. In doing so, the handle 62 is necessarily moved to the closed position, and the valve arrangement 50 is closed. Disconnection of the coupling whilst the valve arrangement 50 is open is thus prevented.

The latch member 66 includes a resilient biasing member 70 (see Figure 15) configured to resiliently bias the latch member 66 towards its extended position. In this embodiment, the resilient biasing member is a compression spring 70. The compression spring 70 is of a strength such that depressing the latch member 66 would be difficult by hand, without a tool. In this embodiment, the force required to fully compress the spring 70 is approximately 85N, so beyond the strength that can be applied using a single finger, even if the latch member 66 were accessible.

The latch member 66 of this embodiment has a body 72a and a cover 72b. The cover 72b defines a void 74 in which the spring 70 is held. The cover 72b extends within the interior of the body 72a to define the void 74, creating a seal with the body 72a and so protecting the spring 70 from fluid ingress. Freezing of the spring 70, which could lead to disabling of the latch member 66, is thus inhibited. The coupling 10 of this embodiment is provided with a right-hand thread arrangement. In an alternative embodiment, the coupling is provided with a left-hand thread arrangement. Where couplings for both gas and liquid are provided, one coupling with a right-hand thread arrangement and one coupling with a left-hand thread arrangement are provided, in order to avoid mis-connection of a gas line to a liquid line, and vice versa.

Referring now to Figures 16 to 21, a coupling for use in a fluid flow line according to an embodiment is indicated generally at 110. Corresponding components of these figures with respect to the embodiment of Figures 1 to 15 are labelled with the prefix ' , and only significant differences are discussed in more detail. It should be understood that the coupling of Figures 16 to 21 is similar to the coupling of previous embodiments described and illustrated herein, and is advantageously configured for use as a quick connect/quick disconnect daybreak coupling, e.g. for use in loading/unloading cryogenic liquified gases (such as in LNG transfer or bunkering).

The first 112 and second 114 parts are configured to be fixed together in order to create a secure fluid flow path. The coupling 110 has a first condition (as shown in Figure 20) in which the first and second parts 112, 114 are connected to one another to define a fluid flow path, and a second condition in which the first and second parts 112, 114 are disconnected from one another (as shown in Figures 16 to 18).

As in the previous embodiments, a sleeve 116 is configured to secure the first 112 and second 114 parts to one another. In this embodiment, the sleeve 116 is rotatable between open and closed positions about a longitudinal axis A-A of the sleeve 116. When the coupling is in the first condition, the sleeve 116 is movable from the open position, in which the coupling 110 is able to transition from the first condition to the second condition (i.e. the first and second parts can be separated from one another), to the closed position, in which transition of the coupling 110 from the first condition to the second condition is prevented (i.e. the first and second parts are secured together). As in the previously described embodiments, the sleeve 116 is rotatable keyed to the first part 112, but is axially located on the first part 112.

As in the previously described embodiments, the sleeve 116 includes an opposing pair of handles 121, which allow the sleeve 116 to be easily grasped and rotated. The first and second parts 112, 114 are secured together (i.e. when the sleeve 116 is rotated from the open position to the closed position), via an internal thread 117 provided on the sleeve 116, and corresponding external thread portions 119 provided on the second part 114. The internal thread 117 and external thread portions 119 are of a multi-start configuration, in accordance with the threads 17 and 19 in the embodiment of Figures 8, 8a and 8b.

The driving force of the unscrewing (i.e. disconnecting) of the first and second parts assists in unlocking any frozen components, e.g. when handling cryogenic fluids.

The coupling 110 has a blocking mechanism 118. When the coupling 110 is in the first condition and the sleeve 116 is in the open position, the coupling 110 is configured to be operable to activate the blocking mechanism 118 during a transition of the coupling 110 from the first condition to the second condition (i.e. during separation of the first and second parts). Activation of the blocking mechanism 118 prevents movement of the sleeve 116 from the open position to the closed position when the first and second parts have been separated from one another. In the embodiment, the first part 112 includes the blocking mechanism 118. The blocking mechanism 118 is intended to prevent/limit movement of the sleeve 116.

In this embodiment, the blocking mechanism 118 includes a blocking member 128 pivotally secured to the first part 112. The point of pivotal connection is radially inboard of the internal diameter of the sleeve 116. The blocking member 128 includes a leg portion 176 and a hook portion 178. The blocking member 128 is mounted to the first part 112 such that it is operable to move from an active state to an inactive state. Put another way, the blocking member 128 can be pivoted between the active and inactive states.

As will be apparent from the following description and the drawings, the second part 114 is configured to activate and deactivate the blocking mechanism 114. The second part 114 is configured to activate the blocking mechanism 118 during disconnection of the first 112 and second 114 parts. The second part 114 is configured to deactivate the blocking mechanism 118 when the first 112 and second 114 parts are located for connection to one another.

The second part 114 is provided with a protruding member 180 that is configured to activate and deactivate the blocking mechanism 118. The protruding member 180 extends from the second face 122.

In this embodiment, the protruding member 180 is provided as a substantially rectangular plate member.

The protruding member 180 is provided with an aperture 186 therethrough. The aperture 186 is provided proximate a distal end of the protruding member 180.

As in the previously described embodiments, the first part 112 has a first face 120, and the second part 114 has a second face 122. The first 120 and second 122 faces are configured to abut one another when the first 112 and second 114 parts are correctly located for connection to one another. That is, the first 120 and second 122 faces are in intended to be contact with one another, without pockets or recesses in which fluid could collect. Abutment of the first 120 and second 122 faces limits the collection of fluid between the first 112 and second 114 parts, so limiting leakage on disconnection of the coupling 110.

The first part 112 defines a cavity 182. In this embodiment, the cavity 182 is provided in the first face 120 (i.e. so as to be re-entrant and extend in a direction axially behind the first face 120). The protruding member 180 is configured to extend into the cavity 182 (i.e. axially beyond the first face 120) when the first 112 and second 114 parts are correctly located for connection to one another, as illustrated in Figure 20, in order to deactivate the blocking mechanism 118.

The coupling 110 is configured such that, when the first and second parts are in the second condition (i.e. disconnected from one another), e.g. as illustrated in Figure 18, the blocking mechanism 118 is in the active state. As can be seen most clearly in Figure 19, in the active state, a portion of the blocking member 128 is positioned within a recess 184 provided on the sleeve 116. More particularly, the end of the leg portion 176 of the blocking member 128 is positioned in the recess 184 when the blocking mechanism is in the active state. In this embodiment, the coupling 110 is configured such that, when the end of the leg portion 176 is located in the recess 184 of the sleeve 116, the sleeve 116 is prevented from rotation from the open position to the closed position.

The coupling 110 is configured such that, when the first and second parts 112, 114 are brought together for connection to one another, the protruding member 180 extends in to the cavity 182. During transition of the coupling 110 from the second condition to the first condition, the protruding member 180 engages the blocking mechanism 118, and drives the blocking mechanism 118 into the inactive state. More particularly, the protruding member 180 drives the leg portion 176 out of the sleeve recess 184, to permit movement of the sleeve 116 (i.e. rotation from the open position to the closed position). It will be understood, therefore, that the blocking member 128 is caused to pivot from the active state to the inactive state, during transition of the coupling 110 from the second condition to the first condition.

As can be seen from Figures 16 to 21, in this embodiment, the sleeve 116 includes only a single recess 184 and single blocking member 128, inter-arranged so that the blocking member 128 can only locate in the recess 184 when the sleeve 116 is in the open position. Moreover, it can be seen that the blocking member 128 pivots about a point radially inboard of the sleeve 116. In order to separate the first and second parts 112, 114 from the first condition, the sleeve 116 must be in the open position. As such, it will be understood that deactivation and activation of the blocking mechanism 118 can only occur when the sleeve 116 is in a single orientation, i.e. the open position. As in the previously described embodiment of Figures 1-15, when the blocking mechanism 118 is in the active state, the blocking member 128 lies in the path of the sleeve 116, preventing movement of the sleeve 116 to the close position.

During transition of the coupling from the first condition to the second condition, the protruding member 180 engages the blocking member 128, to drive the blocking member 128 into the active state. More particularly, during disconnection of the first and second parts 112, 114, an edge of the aperture 186 engages the hook portion 178, to drive the blocking member 128 into the active state. The blocking member 128 is caused to pivot, so that the hook portion 178 is released from the aperture 186, and the leg portion 176 is driven into the sleeve recess 184.

As will be understood from the above description, activation of the blocking mechanism 118 occurs during disconnection of the first and second parts 112, 114, whereas deactivation of the blocking mechanism 118 occurs during connection of the first and second parts 112, 114. In this embodiment, the protruding member 180 is configured to deactivate the blocking mechanism 118, during transition of the coupling from the second condition to the first condition, when the sleeve is in the open position. In addition, the protruding member 180 is configured to activate the blocking mechanism 118 during disconnection of the first 112 and second 114 parts, when the sleeve is in the open position.

Therefore, movement of the sleeve 116 from the open position to the closed position is prevented, unless the coupling 110 is in the first condition. That is, the first and second parts cannot be secured together unless the first and second parts are properly located with respect to one another. An operator of the coupling 110 will become aware of incorrect location of the first and second parts 112, 114 due to an inability to move the sleeve 116 from the open position to the closed position, meaning that the operator will then be able to correctly re-locate the first and second parts 112, 114 with respect to one another.

Due to the temperatures experienced in transferring cryogenic fluids, the blocking mechanism can become frozen in place. Activating the blocking mechanism via the second part ensures that the blocking mechanism does not remain in the inactive state when the first and second parts are disconnected. Further, the force exerted onto the blocking mechanism during separation of the first and second parts ensures that the blocking mechanism is driven back into the active state.

Although not provided in the illustrated embodiment, the blocking mechanism 118 may include a biasing element in order to bias the blocking member 128 into the active position. Such an arrangement would help to prevent tampering with the blocking mechanism.

As can be seen from a comparison of Figures 16 to 21 and Figures 1 to 15, the coupling 110 includes a valve arrangement substantially of the kind described with reference to valve arrangement 50 of Figures 9a, 9b, 10, 11 and 12. As such, opening and closing of the fluid line is carried out in a similar manner, with the first part 112 having a first valve head and the second part 114 having a second valve head, which are arranged to abut when the first and second parts 112, 114 are located for connection. Similarly, the coupling 110 includes a handle and latch member arrangement substantially of the kind described with reference to the handle 62 and latch member 66 of Figures 12, 13, 13a, 14 and 15. As such, disconnection of the coupling 110 while the valuable arrangement is open may be prevented.