GB2628095A

GB2628095A - Adapter

Info

Publication number: GB2628095A
Application number: GB2303544.7A
Authority: GB
Inventors: Hjertvikrem Terje; Petersen Kjetil
Original assignee: Baker Hughes Energy Technology UK Ltd
Current assignee: Baker Hughes Energy Technology UK Ltd
Priority date: 2023-03-10
Filing date: 2023-03-10
Publication date: 2024-09-18
Also published as: WO2024188511A1; GB202303544D0

Abstract

An adapter 4 for connecting a rotary actuator 2 to a valve opening mechanism 16 is provided. The adapter 4 includes a rotary driver 30 having a longitudinal axis X-X, an input end 32 and an output end 34. The adapter 4 is configured to connect the rotary actuator 2 to the input end 32 to drive rotation of the rotary driver 30. The output end 34 is configured to connect to the valve opening mechanism 16 so as to drive rotation of the valve opening mechanism 16 to move the valve 14 from one of an open or closed position to the other of the open or closed position. The adapter 4 also includes one or both of: a brake 38, wherein, when the brake 38 is in a first non-braking state the output end of the rotary driver 30 is free to rotate and, when the brake 38 is in a second braking state the output end 34 of the rotary driver 30 cannot rotate; and a clutch 28 configured to disengage the input end 32 from the output end 34. Provided is also a method of operating a valve 14 and a valve operation assembly.

Description

ADAPTER

TECHNICAL FIELD

The present disclosure relates to an adapter, an apparatus and a method for use in opening and closing valves.

BACKGROUND

In various subsea applications including the field of subsea oil and gas production, and the field of subsea sCO2 re-injection, valves on subsea installations can be opened and / or closed by an actuator which can be operated remotely. It is desirable to be able to remove the actuator from a valve, for example so that the actuator can be retrieved to the surface by a remotely operated vehicle (ROV) for maintenance.

The present disclosure provides an adapter for use with an actuator which seeks, amongst other things, to allow for retrieval of the actuator to the surface without the need to stop sCO2 injection or oil and gas production.

SUMMARY

From a first aspect, the disclosure provides an adapter for connecting a rotary actuator to a valve opening mechanism for a valve, the adapter comprising: a rotary driver having a longitudinal axis, an input end and an output end axially spaced from the input end, wherein the adapter is configured to receive a rotary actuator so as to connect the rotary actuator to the input end to drive rotation of the rotary driver, wherein the output end is configured to connect to a valve opening mechanism so as to drive rotation of the valve opening mechanism to move the valve from one of an open or closed position to the other of the open or closed position, the adapter comprising one or both of: a brake, wherein, when the brake is in a first non-braking state the output end of the rotary driver is free to rotate and, when the brake is in a second braking state the output end of the rotary driver cannot rotate; and a clutch configured to disengage the input end of the rotary driver from the output end of the rotary driver.

In any example of the disclosure, the adapter may comprise a gear mechanism for multiplying the drive torque output from the rotary driver.

In any example of the disclosure, the adapter may be for use in a subsea environment.

In any example of the disclosure, the adapter may comprise a receptacle for receiving the rotary actuator.

In any example of the disclosure, the adapter may comprise mating means for mating with the valve opening mechanism.

From a further aspect, the disclosure provides a valve operation assembly comprising: an adapter according to any example of the disclosure; and a rotary actuator removably connected to the input end of the rotary driver. -1 -

From a further aspect, the disclosure provides an assembly comprising: an adapter according to any example of the disclosure or a valve operation assembly according to any example of the disclosure; and apparatus comprising a valve opening mechanism for opening and / or closing a valve, wherein the output end of the rotary driver is removably connected to the valve opening mechanism.

In any example of the disclosure, the apparatus may comprise a valve which can be opened and / or closed by the valve opening mechanism.

In any example of the disclosure, the valve opening mechanism may comprise a rotary to linear motion converter.

In any example of the disclosure, the valve opening mechanism may comprise a return spring mechanism which is configured to bias the valve opening mechanism into a closed position.

In any example of an assembly including the return spring mechanism, when the adapter comprises a clutch, the clutch may be configured to automatically disengage the input end of the rotary driver from the output end of the rotary driver when signal or power supply is lost.

In any example of an assembly including the return spring mechanism, the return spring mechanism may be configured to close the valve when the clutch disengages the input end of the rotary driver from the output end of the rotary driver.

In any example of the disclosure, the assembly may be a subsea assembly and / or the apparatus may be a subsea installation.

From a further aspect, the disclosure provides a method of operating a valve, the method comprising: mating an adapter with a rotary actuator; before or after mating the adapter with the rotary actuator, mating the adapter with a valve opening mechanism for opening and / or closing the valve; and activating a brake in the adapter to hold the valve in a desired position; and / or activating a clutch in the adapter such that a drive output from the rotary actuator is isolated from the valve opening mechanism.

In any example of the disclosure, the method may comprise activating the rotary actuator to drive the valve opening mechanism via the adapter to open or close the valve prior to activating the brake and / or activating the clutch.

In any example of the disclosure, the method may comprise: deactivating the rotary actuator; and /or removing the rotary actuator from the adapter after activating the brake and / or activating the clutch.

In any example of the disclosure, the method may comprise retrieving the rotary actuator to a surface or on-shore location; and!or mating a further adapter with the rotary actuator; and / or using the rotary actuator to open and or close further valves.

In any example of the disclosure, the valve may be a subsea valve.

In any example of the disclosure, the adapter may be an adapter according to any example of the disclosure, and /or the adapter, the rotary actuator and the valve opening mechanism may form an assembly according to any example of the disclosure.

Although certain advantages are discussed below in relation to the features detailed above, other advantages of these features may become apparent to the skilled person following the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more non-limiting examples will now be described, by way of example only, and with reference to the accompanying figures in which: Figure 1 is a schematic representation of a subsea assembly according to an example of the disclosure; Figure 2 is a cross sectional view of an adapter according to an example of

the disclosure;

Figure 3 is a side view of a subsea assembly according to an example of the disclosure, shown in partial cross section; Figure 4A is a detailed cross sectional view of a part of the subsea assembly of Figure 3; Figure 4B is a detailed cross sectional view of another part of the subsea assembly of Figure 3; and Figure 5 is a schematic diagram showing a method of operating a valve of a subsea installation according to an example of the disclosure.

DETAILED DESCRIPTION

According to various examples of the disclosure, an adapter is provided for use with a rotary actuator for opening and / or closing a valve. Although the adapter and rotary actuator could be used to open valves in various different environments, at least in some examples, the adapter and rotary actuator may be used to open and / or close one or more valves on a subsea installation such as, for example, a valve arrangement such as a Christmas tree (XT) or a manifold. It will be understood that such a subsea installation could be used in a variety of subsea applications including but not limited to subsea oil and gas production and subsea sCO2 reinjection.

Referring to Figure 1, a schematic representation of a subsea assembly including a rotary actuator 2, adapter 4 and subsea installation 6 according to one example of the disclosure is shown. The subsea installation 6 can be any installation including a valve which is required to be opened and / or closed in the subsea environment, such as for example, a Christmas tree (XT) or a manifold for CO2 injection into a subsea storage site or for oil and gas production.

The rotary actuator 2 may be any suitable type of rotary actuator, in other words any type of actuator which produces a rotary output or rotational driving force or torque. The rotary actuator 2 is a separate component which can be mated with the adapter 4. In any example of the disclosure, the rotary actuator can be fixed to the adapter by any suitable fixing means such as, for example, a clip mechanism or one or more fasteners such as nuts and bolts. The rotary actuator 2 can be mated with the adapter and removed from it either manually or by other means, for example by an ROV in a subsea environment. Suitable actuators include hydraulic actuators and electrical actuators. In the example of Figure 1, the rotary actuator 2 is a rotary electrical actuator (REA).

In any example of the disclosure, the rotary actuator may be controlled remotely, for example through a wired or wireless connection. The rotary actuator may be controlled remotely from a location removed from the subsea installation such as for example, from a surface location or from a location on land. In other examples, the rotary actuator could be controlled manually, for example by a diver, or by a ROV.

In some examples and as shown in Figure 1, the rotary actuator is controlled by a subsea control module 8. The subsea control module 8 may be connected to the surface (not shown) by service lines 10 including electrical, optical and / or hydraulic cables as required. The subsea control module 8 may be an electronic control module. Service lines 12 (including electrical, optical and / or hydraulic cables as required) may be provided between the subsea control module 8 and the rotary actuator 2 for controlling operation of the rotary actuator 2.

The subsea installation 6 includes a valve 14 for controlling flow of a fluid therethrough such that when the valve 14 is open, fluid can flow though the valve and when the valve 14 is closed, no fluid can flow therethrough. The valve can take various forms and includes a valve opening mechanism 16. In some examples, the valve 14 could be a rotary valve (not shown) in which the valve opening mechanism may be a rotary mechanism which is rotatable between a closed position in which it extends across a flow passage such that the valve is closed and an open position in which it extends across only part of the flow passage such that the valve 14 is open. In such rotary valves, the rotary output produced by the rotary actuator could be used to rotate the valve opening mechanism between the open and closed positions.

In other examples including but not limited to the example shown in Figure 1, the valve 14 is a linear valve, for example a gate valve. The valve may have a valve stem (not shown) configured to move in an axial direction shown by the arrows A in Figure 1. The valve stem (not shown) is configured to move between a first position (not shown) in which it is in engagement with a valve bonnet (not shown) such that the valve is closed and a second position (not shown) in which it is axially spaced from the valve bonnet such that the valve is open. In some examples including those in which the valve is a linear valve, the valve 14 includes a valve opening mechanism 16 including a rotary to linear motion converter 18 configured to convert rotary motion to linear motion. In any example, the rotary to linear motion converter 18 may include any suitable mechanism including for example a ball screw having a threaded shaft 20 along which a screw 22 may move axially.

As seen in Figure 1, the valve opening mechanism 16 may also include a return spring mechanism 24 which is configured to bias the valve opening mechanism 16 into the closed position such that in the event of a loss of rotary input to the rotary to linear motion converter 18, the valve is automatically closed by the return spring mechanism 24. Although the return spring mechanism 24 could take various forms, -4 -in the example shown the return spring mechanism 24 comprises a compression spring 26 which is mounted around the shaft 20. The compression spring 26 extends between the valve 14 and the screw 22 so as to bias the screw 22 away from the valve 14. The rotary to linear motion converter 18 may act against the biasing action of the spring 26 in normal operation, such that the valve position is determined by the action of the rotary to linear motion converter 18. However, when no force is input to the rotary to linear motion converter 18 such that no axial force acts on the screw 22, the spring 26 acts to cause the threaded shaft 20 to move away from the valve stem to close the valve 14. At least in some examples of the disclosure, the rotary input to the rotary to linear motion converter 18 may be disconnected by the action of a clutch 28 as will be described in further detail below. Activation of the clutch 28 may therefore cause the return spring mechanism 20 to close the valve, thus providing a failsafe.

The adapter 4 according to any example of the disclosure is configured to be positioned between the rotary actuator 2 and the valve opening mechanism 16. In any example of the disclosure, the adapter 4 includes one or more electrical connectors for providing an electrical connection between the rotary driver 2 and the adapter 4, the adapter 4 and the valve opening mechanism 16 and / or the subsea control module 8 or another controller. In any example of the disclosure, the adapter 4 includes a rotary driver 30 having a longitudinal axis X-X, an input end 32 and an output end 34 axially spaced from the input end 32. The adapter 4 is configured to receive the rotary actuator 2 so as to connect the rotary actuator 2 to the input end 32 to drive rotation of the rotary driver 30. The output end 34 of the rotary driver 30 is configured to connect to the valve opening mechanism 16 so as to drive rotation of the valve opening mechanism to move the valve 14 from one of an open or closed position to the other of the open or closed positions.

In any example of the disclosure and as shown in Figure 1, the adapter 4 may include a housing 36 which may be sealed against the external environment and may be internally pressurised for use in a subsea environment.

The adapter 4 may also include a brake 38 as will be described in further detail below. In any example of the disclosure, the brake 38 may be located inside the housing.

The brake 38 can be electrically operated or mechanically operated as required. In any example of the disclosure, the brake 38 can be an electromagnetic brake. When the brake 38 is in a first non-braking state at least the output end of the rotary driver 30, in some examples the rotary driver 30, is free to rotate and, when the brake 38 is in a second braking state at least the output end 34 of the rotary driver 30, in some examples the rotary driver 30, cannot rotate such that, when the adapter 4 is engaged with both the rotary actuator 2 and the valve opening mechanism 16, the valve 14 is held in an open or closed position. It will be understood that when the brake 38 is activated (in other words, when the brake is in the braking position), the valve 14 can be held or locked in an open or closed position by the adapter 4 and the brake 38. Thus, the valve 14 can be retained in a desired open or closed position while the rotary actuator 2 is removed from the adapter 4, for example to be retrieved to the surface for maintenance thereon. At least in some examples, the brake 38 when activated can act to retain the valve 14 in a desired open or closed position and so can act to save power. This is because, when the brake is not activated, power may be required to provide an output from the rotary actuator 2 to hold the valve 14 in the desired open or closed position. In contrast, when the brake is activated, the power driving the rotary actuator may be switched off as no such output is required. Further, the brake may provide a safety mechanism to hold the valve in a desired position in the result of a system failure when the brake is configured to be activated automatically when a signal is received, or power or torque output from the rotary actuator is lost. In any example of the disclosure, the brake 38 may be provided on and may be coaxial with the rotary driver 38.

In any example of the disclosure, the adapter 4 can include a clutch 28 as described above. In any example of the disclosure, the clutch 28 may be located inside the housing 36.

The clutch 28 can be electrically operated or mechanically operated as required. In any example of the disclosure, the clutch 28 can be an electromagnetic clutch. In any example of the disclosure, the clutch 28 may be provided on and may be coaxial with the rotary driver 30. The clutch 28 is configured to engage the input end 32 of the rotary driver 30 with the output end 34 of the rotary driver 30 such that the drive input from the rotary actuator 2 drives the valve opening mechanism 16 when the clutch 28 is in a first, deactivated state. In any example of the disclosure, the adapter may be configured such that the clutch is in the first, deactivated state when the clutch receives a signal, for example an electrical signal via the adapter. The clutch 28 is also configured to disengage the input end 32 of the rotary driver 30 from the output end 34 of the rotary driver 30 such that the drive input from the rotary actuator 2 is disengaged from the valve opening mechanism 16 when the clutch 28 is in a second, activated state. . Thus, the clutch 28 may be configured such that the rotary actuator 2 can act to open or close the valve 14 via the adapter 4 only when the clutch 28 is in the second state. In any example of the disclosure, the clutch may be caused to move to the second activated state on receipt of a signal. In other examples, loss of power to the adapter may cause the clutch to move from the first state to the second activated state.

In some examples in which the valve opening mechanism 16 includes a return spring mechanism 20 as described above, the clutch 28 may be activated to allow the return spring mechanism 20 to act to close the valve 14, thus providing a failsafe mechanism. In examples in which the clutch 28 is activated by a loss of power or signal, the return spring mechanism 20 and the clutch 28 may act as a failsafe mechanism to close the valve when power to the adapter 4 is lost.

It will be understood that as the adapter 4 can include one or both of a brake and a clutch, the adapter can be used with any standard rotary actuator such that no specialist actuator including components such as a brake and/or a clutch need be provided. It will be understood however that in examples in which the adapter includes only a brake, a clutch may be provided in the rotary actuator or in the valve opening mechanism if desired. Further, in examples in which the adapter includes only a clutch, a brake may be provided in the rotary actuator or in the valve opening mechanism if desired.

In any example of the disclosure, the adapter 4 can include a gear mechanism 40. In any example of the disclosure, the gear mechanism 40 may be located inside the housing 36. The gear mechanism 40 is configured to multiply the drive torque output from the output end 34 the rotary driver 30 to drive the opening of the valve 14. It will be understood that the gear mechanism 40 can be configured to multiply -6 -the drive torque output to reduce or increase the drive torque output by any desired amount. In any example of the disclosure, the gear mechanism 40 may be a planetary gear mechanism. In any example of the disclosure, the gear mechanism 40 may be provided on and may be coaxial with the rotary driver 30.

In any example of the disclosure, the brake 38 and the clutch 28 and/or the gear mechanism 40 can be arranged in any order, for example at any axial position on the rotary driver 30.

The adapter 4 may include a receptacle 42 for receiving the rotary actuator 2. The receptacle 42 has an open end 44 into which the rotary actuator 2 can be inserted. The receptacle 42 may extend axially away from the input end 24 of the rotary driver 30. In some examples, the receptacle 42 extends axially away from an end 46 of the housing 36 located adjacent the input end 32 of the rotary driver 30. The receptacle 42 may have one or more side walls 48 configured to guide the rotary actuator 2 into axial alignment with the rotary driver 30. In any example of the disclosure, the receptacle 42 can be annular. In any example of the disclosure, the receptacle 42 can be concentric with the longitudinal axis X-X.

The adapter 4 will now be described in further detail with reference to Figure 2.

Those features shown and described in relation to Figure 1 are given the same reference numbers and are not described again here. As seen in Figure 2, the receptacle 42 can be a bucket type receptacle which may be connected to the housing 36 by any suitable fastening means 50 such as for example screws, rivets or nuts and bolts.

The input end 32 of the rotary driver 30 extends axially outwardly from the base 52 of the receptacle 42. Inside the housing 36, the brake 38 extends around the rotary driver 30. In this example, the brake 38 is an electromagnetic brake.

A clutch 28 is also provided inside the housing 36 and axially spaced from the brake 38. The clutch 28 comprises a first part 54 and a second part 56 configured such that when the first part 54 is in a first axial position when the clutch is in the first, deactivated state, it is in driving engagement with the second part 56. The rotary driver 30 includes a first drive shaft 58 extending from the input end 32 of the rotary driver 30 to the clutch 28. The first part 54 of the clutch 28 is provided on the first drive shaft 58. The second part 56 of the clutch 28 is provided on a second drive shaft 60 which is driven by the first drive shaft 58 when the clutch is in the first, deactivated state.

A gear mechanism 40, in this example a planetary gear mechanism mounted on the second drive shaft 60 is also provided inside the housing 36 and axially spaced from the clutch 28. An output shaft 62 is configured to provide a rotary drive output from the gear mechanism 40.

Mating means such as a socket 64 is provided extending axially outwardly from the housing 36 adjacent the output shaft 62 at the output end of the rotary driver 30. The socket 64 is configured to mate with and be fixed to a valve opening mechanism 16 (for example by bolts) such as for example a rotary to linear motion converter of the type shown in figure 1.

Figure 3 is a side view of a subsea assembly 70 according to another example of the disclosure and in which many of the parts shown correspond to those of the subsea assembly described above and so are given the same reference numbers. The subsea assembly comprises an XT 72 including at least one valve (not shown) to which a valve opening mechanism including a rotary to linear motion converter 18 is attached, a rotary actuator 2 and an adapter 4.

Figure 4A is a detailed cross sectional view taken at A on Figure 3 and shows the output end 34 of the rotary driver 30 of adapter 4 engaged with the rotary to linear motion converter 18. As seen, the socket 64 comprises an opening 74 for axially receiving and guiding a rotary shaft 76 of the rotary to linear motion converter 18. Although it could take various forms, in any example of the disclosure, the socket 64 may be a square socket such as is known from Industry standard API 17H. The shaft 74 has an end portion with a smaller diameter so as to form a radially extending shoulder 78 which is axially removed from the end of the shaft 76 which engages with the output end 34 of the rotary driver 30. An axially outer wall 80 of the socket 64 is positioned to abut against the radially extending shoulder 78 when the shaft 74 is inserted into the tubular opening 74 and is drivingly engaged with the output end 34 of the rotary driver 30 via the socket 64.

Figure 4B is a detailed cross sectional view taken at B on Figure 3 and shows the input end 32 of the rotary driver 30 of adapter 4 engaged with the rotary actuator 2. As seen, the input end 32 of the rotary driver 30 engages with and is driven by a rotary drive output 80 of the rotary actuator 2. The rotary drive output 80 being configured with an opening to receive the input end 32 of the rotary driver 30.

Although it could take various forms, in any example of the disclosure, the opening may be a square socket such as is known from Industry standard API 17H. In any example, it may further include an annular gripper 82 which tapers outwardly from the rotary drive output 80 to engage against the interior of the receptacle 42 and hold the rotary actuator 2 in position within the receptacle 42.

A method of operating a valve of a subsea installation using an adapter according to the disclosure will now be described with reference to Figure 5. At a first step 200, an adapter 4 according to the disclosure is mated with a rotary actuator 2. In some examples and as described above with reference to Figure 4B, this is achieved by the input end 32 of the rotary driver 30 being inserted into a tubular opening in the rotary drive output 80 of the rotary actuator 2.

At a second step 202 the adapter 4 is then also mated with a valve opening mechanism 16 associated with the valve to be operated. In some examples and as described above with reference to Figure 4A, this is achieved by a socket 64 of the adapter 4 receiving a rotary shaft 76 of a rotary to linear motion converter 18 of the valve opening mechanism 16.

It will be understood that suitable connections (such as for example, electric or hydraulic cables) for providing power and/ or control signals to the adapter and / or the actuator and /or the valve opening mechanism may be provided and that these may be connected to the desired components either before or after they are connected to each other.

In any example of the disclosure, step 200 may be carried out at a location remote from the subsea installation, including for example on land or at a surface location. -8 -

The mated adapter 4 and rotary actuator 2 can then be transported to the subsea installation, for example by an ROV, and step 202 can then be carried out, for example by the same or another ROV. It will be understood however that, if preferred, step 202 can be carried out prior to mating the adapter 4 and the rotary actuator 2 (step 200). In this case, the step of mating the adapter 4 and the rotary actuator 2 may be carried out subsea, for example using an ROV.

Once the valve opening mechanism 16, adapter 4 and rotary actuator 2 are mated, the rotary actuator 2 is activated via suitable controls such as those described above to drive the valve opening mechanism 16 to open or close the valve 14 as required (step 204). While the rotary actuator 2 is activated, in adapters which have a brake, the brake 38 of the adapter 4 is in a non-braking state or, in other words, is disengaged. In adapters which have a clutch 28, the clutch is engaged, in other words the clutch is in the first, deactivated state, such that the input end of the rotary driver drives rotation of the output end of the rotary driver. In adapters which also have a gear mechanism 40, this will act to multiply the drive output from the adapter 4 rotary driver 30 as described above.

At step 206, optionally after the valve has been opened or closed as desired, the brake 38 can be switched to the braking state or activated such that at least the output end 34 of the rotary driver 30 cannot rotate. The rotary actuator 2 can then be deactivated or powered down if desired.

The rotary actuator 2 can then be removed from the adapter 4 (step 208) which can be left in-situ mated with the valve opening mechanism 16. At least in some examples, the rotary actuator 2 may be removed by an ROV and retrieved to a surface or on-shore location, for example for maintenance. In other examples, the rotary actuator 2 may subsequently be used to open and or close further valves and may be mated with another adapter if required.

In other examples, the valve may have been closed by the rotary actuator 2 and it may be preferable to remove both the adapter 4 and the rotary actuator 2 from the subsea installation instead of leaving the adapter in-situ as described above.

In addition or as an alternative to the above, at any stage after the valve opening mechanism 16, adapter 4 and rotary actuator 2 have been mated, the clutch 28 may be activated as shown at step 210. At least in some examples, the clutch 28 is configured such that a loss of power to the adapter 4 causes the clutch to be automatically activated (in other words to switch to the second, activated state).

This in turn causes the spring return mechanism 24 to act to close the valve 14 without the need to for the rotary actuator 2 to drive the adapter 4 to close the valve via the valve opening mechanism 16.

While the disclosure has been described in detail in connection with only a limited number of examples, it should be readily understood that the disclosure is not limited to such disclosed examples. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of disclosure. Additionally, while various examples of the disclosure have been described, it is to be understood that aspects of the disclosure may include only some of the described examples. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

-10 -

Claims

CLAIMS1. An adapter for connecting a rotary actuator to a valve opening mechanism for a valve, the adapter comprising: a rotary driver having a longitudinal axis, an input end and an output end axially spaced from the input end, wherein the adapter is configured to receive a rotary actuator so as to connect the rotary actuator to the input end to drive rotation of the rotary driver, wherein the output end is configured to connect to a valve opening mechanism so as to drive rotation of the valve opening mechanism to move the valve from one of an open or closed position to the other of the open or closed position, the adapter comprising one or both of: a brake, wherein, when the brake is in a first non-braking state the output end of the rotary driver is free to rotate and, when the brake is in a second braking state the output end of the rotary driver cannot rotate; and a clutch configured to disengage the input end of the rotary driver from the output end of the rotary driver.
2. An adapter as claimed in claim 1, wherein the adapter comprises a gear mechanism for multiplying the drive torque output from the rotary driver.
3. An adapter as claimed in claim 1 or 2, wherein the adapter is for use in a subsea environment.
4. An adapter as claimed in any preceding claim, comprising a receptacle for receiving the rotary actuator.
5. An adapter as claimed in any preceding claim, comprising mating means for mating with the valve opening mechanism.
6. A valve operation assembly comprising: an adapter as claimed in any preceding claim; and a rotary actuator removably connected to the input end of the rotary driver.
7. An assembly comprising: an adapter as claimed in any of claims 1 to 5 or a valve operation assembly as claimed in claim 6; and apparatus comprising a valve opening mechanism for opening and / or closing a valve, wherein the output end of the rotary driver is removably connected to the valve opening mechanism.
8. An assembly as claimed in claim 7, the apparatus comprising a valve which can be opened and / or closed by the valve opening mechanism.
9. An assembly as claimed in claim 7 or 8, the valve opening mechanism comprising a rotary to linear motion converter.
10. An assembly as claimed in claim 7, 8 or 9, the valve opening mechanism comprising a return spring mechanism which is configured to bias the valve opening mechanism into a closed position.
11. An assembly as claimed in claim 10, wherein, when the adapter comprises a clutch, the clutch is configured to automatically disengage the input end of the rotary driver from the output end of the rotary driver when signal or power supply is lost.
12. An assembly as claimed in claim 10 or 11, wherein the return spring mechanism is configured to close the valve when the clutch disengages the input end of the rotary driver from the output end of the rotary driver.
13. An assembly as claimed in any of claims 7 to 12, wherein the assembly is a subsea assembly and / or the apparatus is a subsea installation.
14. A method of operating a valve, the method comprising: mating an adapter with a rotary actuator; before or after mating the adapter with the rotary actuator, mating the adapter with a valve opening mechanism for opening and / or closing the valve; and activating a brake in the adapter to hold the valve in a desired position; and / or activating a clutch in the adapter such that a drive output from the rotary actuator is isolated from the valve opening mechanism.
15. A method as claimed in claim 14, comprising activating the rotary actuator to drive the valve opening mechanism via the adapter to open or close the valve prior to activating the brake and / or activating the clutch.
16. A method as claimed in claim 15, comprising: deactivating the rotary actuator; and /or removing the rotary actuator from the adapter after activating the brake and / or activating the clutch.
17. A method as claimed in claim 16, comprising retrieving the rotary actuator to a surface or on-shore location; and /or mating a further adapter with the rotary actuator; and / or using the rotary actuator to open and or close further valves.
18. A method as claimed in any of claims 14 to 17, wherein the valve is a subsea valve.
19. A method as claimed in any of claims 14 to 18, wherein the adapter is an adapter as claimed in any of claims 1 to 5, and /or the adapter, the rotary -12 -actuator and the valve opening mechanism form an assembly as claimed in any of claims 7 to 13.