FIELD

This invention relates to an actuator apparatus for a valve, an actuator system and method. BACKGROUND

Actuators are used in a vast array of applications in order to actuate and control tools and equipment. In the oil and gas industry, for example, actuators are used extensively in subsea operations in order to actuate valves in order to control fluid flow to/from a wellbore. Subsea wellhead assemblies are complex and typically include a variety of tools and equipment, many of which are critical to ensure that the well operates efficiently and safely and in some instances it may be necessary to operate a given valve remotely, such as by a remotely operated vehicle. To facilitate this, actuators are provided with an override apparatus which permits the operation of the actuator and the associated valve to be controlled remotely.

While conventional actuators work effectively in many applications, there are drawbacks with conventional systems and equipment, some of which will be discussed below.

SUMMARY According to a first aspect, there is provided an actuator apparatus for a valve, the actuator apparatus comprising: an actuator; an override apparatus; and a transmission system for coupling the override apparatus to the actuator, wherein the transmission system comprises a drive chain arrangement. Beneficially, the use of a drive chain arrangement simplifies the positioning of the override apparatus and facilitates the positioning of the override apparatus to enable backward compatibility with existing systems, and allowing existing "brownfield" systems to be updated. Moreover, the use of a drive chain arrangement provides a simple, efficient and compact arrangement for coupling the override apparatus to the actuator, and precludes the use of more complex and/or expensive gears and bearings.

The transmission system may be configured to convert an input force applied to the override apparatus into an output force acting on the actuator. The input force may comprise a rotary input, such as a rotary drive torque. The input force may be provided by a secondary actuation mechanism, such as a remotely operated vehicle. The output force may comprise at least one of a rotary output force and a linear output force.

In particular embodiments, the override apparatus may be disposed laterally of the actuator. Beneficially, embodiments of the present invention, amongst other things, provides an actuator which has reduced height compared to conventional systems while retaining override functionality. This may be particularly beneficial in applications where access to the actuator apparatus and/or the valve is limited or restricted, such as by adjacent tools or equipment. Moreover, the actuator apparatus may be retrofitted to conventional equipment without increasing the overall height of the system. Embodiments of the present invention may permit a taller actuator apparatus to be used without increasing overall vertical envelope of the apparatus.

The override apparatus may comprise an input shaft. The input shaft may form part of the transmission system of the actuator apparatus. The input shaft may be arranged to rotate about a first axis. The first axis may comprise a horizontal or substantially horizontal axis.

The override apparatus may comprise an output shaft. The output shaft may form part of the transmission system of the actuator apparatus. The output shaft may be arranged to rotate about a second axis. The second axis may comprise a vertical or substantially vertical axis.

The override apparatus may comprise a gear arrangement. The gear arrangement may form part of the transmission system of the actuator apparatus. The gear arrangement may couple the input shaft to the output shaft. The gear arrangement may comprise a bevel gear arrangement. The gear arrangement may be configured to convert rotation of the input shaft about the first axis into rotation of the output shaft about the second axis. In use, rotation of the input shaft by the rotary input may drive rotation of the output shaft about the second axis. The override apparatus may comprise a sprocket member, such as a sprocket wheel, having one or more, and in particular embodiments a plurality of, sprockets. The sprocket member may form part of the transmission system of the actuator apparatus. The sprocket may be disposed on, coupled to, or formed on, the output shaft. In use, the sprocket may support and engage the drive chain arrangement so that rotation of the output shaft drives rotation of the sprocket which in turn drives the drive chain arrangement.

The override apparatus may comprise a housing.

The input shaft may be rotationally mounted to the housing of the override apparatus.

The override apparatus may comprise a bearing arrangement. The input shaft may be rotationally mounted to the housing via the bearing arrangement. The bearing arrangement may comprise one or more angular contact bearings for rotationally supporting the input shaft.

The output shaft may be rotationally mounted to the housing of the override apparatus. The output shaft may be rotationally mounted to the housing via the bearing arrangement. The bearing arrangement may comprise one or more angular contact bearing for rotationally supporting the output shaft. The override apparatus may comprise a seal arrangement. The seal arrangement may prevent leakage of fluid between components of the override apparatus.

The seal arrangement may comprise one or more seal element, such as an o-ring seal element. The actuator may comprise an actuation member. The actuation member may comprise a shaft.

The actuator may comprise a sprocket member, such as a sprocket wheel, having one or more, and in particular embodiments a plurality of, sprockets. The sprocket member may form part of the transmission system of the actuator apparatus. The sprocket member may be disposed on, coupled to, or formed on, the actuation member. In use, the sprocket member may support and engage the drive chain arrangement so that rotation of the drive chain drives rotation of the sprocket member which in turn drives rotation of the actuation member.

The actuator may comprise a housing. The actuation member may be keyed to the housing of the actuator.

The apparatus may comprise a gearbox. The gearbox may comprise a strain wave gearbox, such as a harmonic drive gearbox.

The actuator apparatus may comprise a visual position indicator arrangement. The apparatus may comprise an indicator shaft. The indicator shaft may be coupled to the gearbox. The apparatus may comprise an indicator sleeve.

The actuator apparatus may comprise an interface device. The interface device may comprise an ROV interface device. The interface device may be coupled to, or formed on, the input shaft of the override apparatus. The actuator apparatus may further comprises a handling arrangement. The handling arrangement may comprise a lifting mandrel. The handling arrangement may be configured to facilitate engagement with a tool for retrieving the apparatus to surface or other remote location. The handling apparatus may comprise a neck portion. The handling apparatus may comprise a head portion.

The actuator apparatus may be provided in combination with, or form part of, a valve assembly comprising a valve.

According to a second aspect, there is provided a valve assembly comprising: a valve; and an actuator apparatus according to the first aspect.

In particular embodiments, the valve may comprise a choke valve.

However, the valve may comprise any suitable valve, such as a needle valve, gate valve, ball valve or the like. The actuator apparatus or the valve assembly may be provided in combination with, or form part of, a subsea system.

According to a third aspect, there is provided a subsea system comprising an actuator apparatus according to the first aspect or a valve assembly according to the second aspect. According to a fourth aspect, there is provided a method for actuating a valve, the method comprising: providing an actuator apparatus comprising: an actuator; an override apparatus; and a transmission system for coupling the override apparatus to the actuator, wherein the transmission system comprises a drive chain arrangement; and applying a rotary input force to the override apparatus, the rotary input force converted by the actuator apparatus to a output force for actuating the valve.

According to a fifth aspect, there is provided an actuator apparatus for a valve, the actuator apparatus comprising: an actuator; an override apparatus, wherein the override apparatus is disposed laterally of the actuator.

Embodiments of the present invention, amongst other things, provides an actuator which has reduced height compared to conventional systems while retaining override functionality. This may be particularly beneficial in applications where access to the actuator apparatus and/or the valve is limited or restricted, such as by adjacent tools or equipment. Moreover, the actuator apparatus may be retrofitted to conventional equipment without increasing the overall height of the system. Embodiments of the present invention may permit a taller actuator apparatus to be used without increasing overall vertical envelope of the apparatus.

The actuator apparatus may comprise a transmission system. The transmission system may comprise a drive chain arrangement, such as the drive chain arrangement described above. In other embodiments of this second aspect, the transmission system may alternatively or additionally comprise a drive belt arrangement, a gear arrangement or the like.

According to a sixth aspect, there is provided a valve assembly comprising: a valve; and an actuator apparatus according to the fifth aspect.

According to a seventh aspect, there is provided a subsea system comprising an actuator apparatus according to the fifth aspect or a valve assembly according to the sixth aspect. According to an eighth aspect, there is provided a method for actuating a valve, the method comprising: providing an actuator apparatus comprising: an actuator; and an override apparatus, wherein the override apparatus is disposed laterally of the actuator; and applying a rotary input force to the override apparatus, the rotary input force converted by the actuator apparatus to a output force for actuating the valve.

It should be understood that the features defined above or below may be utilised, either alone or in combination with any other defined feature. For example, the features of the actuator apparatus of the first aspect may be utilised in the actuator apparatus of the fifth aspect and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of an actuator apparatus comprising an override apparatus according to an embodiment;

Figure 2 shows another second perspective view of the apparatus shown in Figure 1 ;

Figure 3 shows another perspective view of the apparatus shown in Figure 1 ;

Figure 4 shows another perspective view of the apparatus shown in Figure 1, with cover removed; Figure 5 shows a section view of the apparatus shown in Figure 1 ;

Figure 6 shows another section view of the apparatus shown in Figure 1 ;

Figure 7 shows a front view of the apparatus shown in Figure 1 ;

Figure 8 shows a side view of the apparatus shown in Figure 1 , with a partial cut away view of part of the apparatus; Figure 9 shows an enlarged view of the part of the apparatus shown in the cut away view in Figure 8;

Figure 10 shows a perspective view of an actuator apparatus according to a second embodiment; Figure 11 shows another perspective view of the actuator shown in Figure 10, showing the transmission system; and

Figure 12 shows a subsea system in which embodiments may be employed. DETAILED DESCRIPTION

Referring first to Figures 1 to 4 of the accompanying drawings, there is shown an actuator apparatus 10 according to an embodiment of the present invention. In use, the actuator apparatus 10 is coupled to and operatively associated with a valve 12 via an adapter 14. In the illustrated embodiment, the valve 12 comprises a subsea choke valve. However, it will be recognised that the apparatus 10 may be configured for operation with a variety of different valves types, including for example but not exclusively a needle valve, gate valve or the like.

As shown in Figures 1 to 4, the actuator apparatus 10 comprises an actuator 16 for actuating the valve 12 and an override apparatus 18. The override apparatus 18 is operatively associated with the actuator 16 and permits the actuator 16 to be operated by a secondary actuation mechanism, such as by a remotely operated vehicle (ROV). As shown in Figure 1, the override apparatus 18 is disposed laterally of the actuator 16 and utilises as the secondary actuation mechanism a transmission arrangement including a transmission chain 32 (shown in Figure 4) to operate the actuator 16.

Details of the actuator apparatus 10 will now be described with reference to Figures 1 to 4 and also to Figures 5 and 6 of the accompanying drawings, which show sectional views of the actuator apparatus 10. As shown in Figure 5, the actuator 16 comprises a housing 20. An actuation member in the form of shaft 22 - in the illustrated embodiment a spur gear shaft - is rotationally mounted in the housing 18 via a key 24.

The shaft 22 is operatively associated with a stepping unit 26 which, during normal operations, controls the position of a stylus 28 which connects the actuator 16 to the valve 12 and permits operation of the valve 12 by the actuator 16.

As described above, the actuator apparatus 10 also comprises an override apparatus 18. As shown in Figures 4 and 5, an upper end portion of the shaft 22 of the actuator 16 comprises or defines a sprocket member 30 for receiving a transmission chain 32. In use, the transmission train 32 couples the actuator 16 to the override apparatus 18 and permits manipulation of the actuator 16 by a secondary actuation mechanism, such as by a remotely operated vehicle as will be described further below.

Referring now in particular to Figure 6 of the accompanying drawings, it can be seen that the override apparatus 18 comprises an input shaft 34 and an output shaft 36. A gear 38 - in the illustrated embodiment a bevel gear - is disposed or formed on the input shaft 34 while a gear 40 - in the illustrated embodiment a bevel gear - is disposed or formed on the output shaft 36.

In use, rotation of the input shaft 34 rotates the output shaft 36 due to the engagement between the gears 38, 40. As shown in Figure 6, the input shaft 34 is orientated and rotates about a first axis A while the output shaft 36 is orientated and rotates about a second axis B, the second axis B being perpendicular or substantially perpendicular to the axis A of the input shaft 34. In the illustrated embodiment, the first axis A is horizontal or substantially horizontal while the second axis B is vertical or substantially vertical axis. However, it will be recognised that the input shaft 34 and the output shaft 36 may be orientated in any direction or at any relative angle where required.

An upper end portion of the output shaft 36 of the override apparatus 18 comprises or defines a sprocket member 42 for receiving the transmission chain 32. The sprocket member 42 defines a drive sprocket of the actuator apparatus 10 while the sprocket member 30 of the actuator 16 defines a driven sprocket.

As described above, in use, the input shaft 34 rotates the output shaft 36 due to the engagement between the gears 38, 40. This, in turn, results in rotation of the sprocket 42, the transmission chain 32, the sprocket member 30 and the shaft 22.

In the illustrated embodiment, the override apparatus 18 has a housing 44 (the "override apparatus housing") which is separate from the actuator housing 20. The housing 44 and the actuator housing 20 are coupled together via an inner cover 46 and an outer cover 48. Beneficially, the outer cover 48 permits separate access to the transmission arrangement. However, it will be recognised that the override apparatus housing 44 and the actuator housing 20 may comprise a single housing where appropriate.

As shown in Figure 6, the override apparatus housing 44 includes a first housing portion 50, the first housing portion 50 housing the input shaft 34 of the override apparatus 18.

The input shaft 34 is rotationally mounted in the first housing portion 50 on bearings 52, which in the illustrated embodiment comprise angular contact bearings.

The bearings 52 are secured in place by a lock arrangement which in the illustrated embodiment a lock nut 54 and a lock washer 56.

While a first end portion of the input shaft 34 (right end as shown in Figure 6) provides mounting for the gear 38, a second end portion of the input shaft 34 (left end as shown in Figure 6) comprises or engages an external interface device 58, which in the illustrated embodiment takes the form of an ROV interface device. In use, rotation of the external interface device 58 rotates the input shaft 34.

An annular cap 60 is secured to the first housing portion 50 by cap screws 62 or the like. The override apparatus housing 44 includes a second housing portion 64, the second housing portion 64 housing the output shaft 36 of the override apparatus 18.

The output shaft 36 is rotationally mounted on bearings 66, which in the illustrated embodiment comprise angular contact bearings. A spacer 68 is interposed between the output shaft 36 and the second housing portion 64.

A seal arrangement provides sealing/prevent fluid leakage between first housing portion 50 and the second housing portion 64 and between the cap 60 and the first housing portion 50. A first seal element 70 of the seal arrangement, which in the illustrated embodiment takes the form of an o-ring seal element, is disposed in a groove 72 disposed in the first housing portion 50 to prevent leakage of fluid between the first housing portion 50 and the second housing portion 64. A second seal element 74 of the seal arrangement, which in the illustrated embodiment takes the form of an o-ring seal element, is disposed in a groove 76 disposed in the cap 60 and prevents leakage of fluid between the first housing portion 50 and the cap 60. A further seal element 78 is disposed in a groove 80 in the cap 60 and in the illustrated embodiment takes the form of a double acting energised o-ring seal element, although other o-ring seal elements or other forms of seal element may be utilised where appropriate.

The apparatus 10 further comprises a handling arrangement which in the illustrated embodiment comprises a lifting mandrel 82. In use, the apparatus 10 can be disconnected from the valve 12 and retrieved using the lifting mandrel 82. The lifting mandrel 82 is coupled to the outer cover 48 of the apparatus 10 via one or more fasteners 84 (two cap screws are shown in Figure 5). The lifting mandrel 82 has a neck portion 86 and a head portion 88 configured to facilitate engagement with a tool (not shown), enabling the apparatus 10 to be retrieved to surface or other remote location.

A seal 90 - in the illustrated embodiment an o-ring seal element - is disposed in a groove 92 in the lifting mandrel 82 and provides sealing between the lifting mandrel 82 and the outer cover 48. Referring now also to Figures 7, 8 and 9 of the accompanying drawings, the apparatus 10 further comprises a harmonic drive gearbox 94 coupled to the housing 44 by fasteners 96, which in the illustrated embodiment take the form of cap screws.

An indicator shaft 98 is coupled to the gearbox 94 by fasteners, in the illustrated embodiment comprising bolts 100 and a washer 102.

A housing cover 104 is also provided, the housing cover 104 housing the gearbox 94 and providing mounting for an indicator sleeve 106 and an indicator 108.

A seal 110 in the illustrated embodiment an o-ring seal element is disposed in a groove 112 in the housing cover 104 and provides sealing between the housing cover 104 and the housing 44.

It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention.

Figures 10 and 11 show an actuator apparatus 1010 according to another embodiment. The actuator apparatus 1010 is similar to the actuator apparatus 10 and like components are represented with like reference signs incremented by 1000.

In this embodiment, the transmission system comprises a drive belt.

In the apparatus 1010, the external interface device is also provided with a receptacle 114. The receptacle 114 may assist a remotely operated vehicle in engaging with the external interface device.

Figure 12 shows a subsea system 2000 in which embodiments may be employed. In the illustrated embodiment, the subsea system 2000 includes a wellhead assembly W comprising an apparatus 2010 and an associated valve V. While in the illustrated embodiment, the apparatus 2010 is substantially identical to the apparatus 10, it will be recognised that the subsea system 2000 may alternatively or additionally comprise the actuator apparatus 1010 or other actuator apparatus according to embodiments of the present invention. The system 2000 comprises a marine riser MR which couples the subsea wellhead W to a surface vessel SV. A remotely operated vehicle ROV is shown (not to scale) engaged with the wellhead W and, in use, the ROV operates the override assembly of the actuator apparatus 10 to permit the valve V to be operated remotely.

This written description uses examples to disclose the invention, including the preferred embodiments, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. Aspects from the various embodiments described, as well as other known equivalents for each such aspects, can be mixed and matched by one of ordinary skill in the art to construct additional embodiments and techniques in accordance with principles of this application.