Submarine electric actuator, apparatus comprising the actuator and method of submarine electric actuation.

Abstract

ACTUATOR AND ASSOCIATED METHODS. The present invention relates to an actuator for providing subsea electrical actuation. The actuator has a screw assembly (5) with a screw and a threaded part, and a housing for the screw assembly. An axial stop prevents axial movement relative to the housing of the screw and the threaded part in normal operating mode. A primary pull provides rotational movement to the screw assembly in normal operating mode. The screw assembly converts the rotational movement to axial movement of a valve member (10) relative to the housing. An override is provided for operating the actuator in an override operating mode, the override releasing at least one of the screw and the threaded part from axial movement relative to the housing in the override operating mode.

Description

1 / 55 Submarine electric actuator, apparatus comprising the actuator and method of submarine electric actuation. TECHNICAL FIELD

[0001] This disclosure relates to an actuator, such as a subsea actuator for actuating a subsea valve; and associated methods, such as valve actuation and / or overriding methods. TECHNICAL OVERVIEW

[0002] In the oil / gas industry, wellheads are typically at least partially controlled using Subsea Control Modules (SCMs), such as where an SCM controls a Christmas Tree (XMT) associated with a production wellhead. The SCM provides well control functions, particularly during the production phase of subsea oil / gas production. The SCM contains electronics for performing a variety of functions, frequently including: processing communications signals, conditioning electrical power supplies, providing status information; and distributing signals and power to / from control valves, pressure / temperature sensors, and the like.

[0003] XMTs typically have multiple fluid barriers to control fluid, pressure, and flow in the well. Periodically, XMTs may require maintenance, inspection, etc. Temporary barriers are often placed using boreholes below the XMT. These boreholes are typically dedicated to such temporary use, and access through these boreholes is only possible Petition 870260034088, dated April 13, 2026, page 6 / 135 2 / 55 when particular valves are opened to allow such access. The valves are typically gate valves operable between a closed position, where the borehole (drilling) (below the XMT) is closed.

[0004] The subject matter of at least some examples in this disclosure may be directed toward overcoming, or at least reducing the effects of, one or more of the problems of the prior art, such as may be described above. SUMMARY

[0005] In accordance with a first aspect, an actuator is provided. The actuator may comprise an electrically operable actuator. The actuator may be for operating a valve. The actuator may comprise a subsea actuator, such as a subsea electric actuator for providing subsea electrical actuation of the valve. The actuator may comprise a screw assembly. The screw assembly may comprise one or more of: a lead screw (main screw), a roller screw, an ACME screw; a ball screw. The screw assembly may comprise a threaded part, such as a female threaded part (e.g., a nut), for receiving the screw. The screw assembly may comprise a roller screw assembly. The screw assembly may comprise a roller screw and a roller nut. The actuator may comprise a housing for the screw assembly.The actuator may comprise an axial stop for preventing axial movement relative to the housing of the screw and the threaded part. The actuator may comprise a primary drive for providing movement. Petition 870260034088, dated April 13, 2026, page 7 / 135 3 / 55 rotational for screw assembly in normal operating mode. The screw assembly may be for conversion from rotational movement to axial movement of the valve member relative to the housing. The actuator may comprise an override for operating the actuator in an override mode. The override may be configured to release at least one of the screw and threaded portion for axial movement relative to the housing. The actuator may be configured to be overridden by releasing at least a portion of the screw assembly. The portion for override release may otherwise be fixed or restrained in normal actuator operation. The actuator may be configured for override by releasing the integrity of the screw assembly, such as releasing the screw assembly relative to an actuator housing.

[0006] A screw assembly may comprise a longitudinal member for axial movement along a central geometric axis of the longitudinal member. The longitudinal member may comprise the screw of the screw assembly. The screw of the screw assembly may be a spindle (shaft). The longitudinal member may comprise a solid member. The longitudinal member may comprise a rigid, solid rod. The screw assembly may comprise a drive for transferring drive to or from the longitudinal member. A threaded part assembly, such as a roller nut assembly, may comprise the drive. The roller nut assembly may comprise a plurality of rollers. Petition 870260034088, dated April 13, 2026, page 8 / 135 4 / 55 for drive transmission between the screw and the roller nut of the roller assembly. The transmission can convert a rotational movement of the screw into a longitudinal movement of the threaded part. Alternatively, the transmission can convert a rotational movement of the threaded part into a longitudinal movement of the screw.

[0007] The screw assembly may be operable by converting rotational motion or torque, such as from a motor (e.g., electric), into axial motion or force. The axial motion or force may be relative to the longitudinal member of the screw and the transmission. For example, screw operation may provide axial motion of the threaded part relative to the screw. The axial motion may comprise linear motion. The screw assembly may include a linear actuator. The actuator may include the motor. The motor may comprise the primary drive for operating the actuator in normal operating mode.

[0008] The screw assembly may be operable to axially pull the valve between positions. The screw assembly may be operable to selectively pull the valve cyclically between open and closed positions. For example, the screw assembly may be operable to push a valve member to an open position and to pull the valve member to a closed position. The screw assembly may comprise a push member. The push member may comprise a push rod. The push rod may comprise a hollow push rod. In accordance with this, the Petition 870260034088, dated April 13, 2026, page 9 / 135 5 / 55 Push member may include a push tube.

[0009] The valve may comprise a valve member, such as a valve stem or valve rod. The valve stem may extend through a stem seal. In at least some examples, the valve assembly may comprise a bonnet, the bonnet housing the stem seal through which the valve stem may extend. The valve may comprise a bore seal member, the bore seal member being configured to sealably occlude access through a bore. The bore may be for providing access below an XMT, such as when an XMT is removed, damaged, inspected or repaired, etc. The valve may comprise a seat for the bore seal member. The bore seal member may comprise a slide. The valve stem may be perpendicular to the bore, with the valve stem being axially movable along its geometric axis perpendicular to the bore.In accordance with this, the hole sealing member may be transversely movable into and out of the hole to respectively close and open the hole [for example, for through-hole access (36)].

[0010] At least one of the screw and the threaded part of the screw assembly can be operatively associated with the valve member. For example, the threaded part can be connected to the valve member in such a way that axial movement of the threaded part axially moves the valve member. In other examples, the screw can be connected to the valve member in such a way that axial movement of the screw... Petition 870260034088, dated 04 / 13 / 2026, page 10 / 135 6 / 55 Axially moves the valve member. The screw or threaded part may be connected to the push member. The portion of the screw assembly connected to the valve member (e.g., via the push member) may be an axially movable member of the screw assembly. The other portion of the valve assembly may be an axially stationary member of the screw assembly, at least during normal or primary actuator operation. For example, the threaded part may be the axially movable member and the screw may be the axially stationary member (or vice versa). The push member may be configured to push the valve stem. The push member may be configured to pull the valve stem. The push member may be lashed to the valve stem.

[0011] The actuator may comprise a housing. The housing may be configured to maintain an axial position of the axially stationary member of the screw assembly. For example, the housing may comprise an axial stop for maintaining the axial position of the screw. The axial stop may prevent axial movement of the axially stationary member in a first and / or a second axial direction. In at least some examples, the housing may prevent axial movement in both axial directions. The axial directions may be parallel to the longitudinal geometric axis of the screw. The housing may limit or prevent movement of the axially stationary member during normal operation of the actuator. In accordance with this, in at least some examples, the actuator may be normally operable to actively Petition 870260034088, dated 04 / 13 / 2026, page 11 / 135 7 / 55 rotate, as driven by the motor, the screw to axially displace the threaded part, consequently axially displacing the valve member associated with the threaded part.

[0012] The actuator may comprise a bearing assembly (bearing assembly, bearing set) comprising a bearing housing containing bearings. The bearings may support at least a portion of the screw assembly. For example, the bearings may support the screw. The bearings may comprise angle contact bearings. The bearings may provide a high degree of axial stiffness. The bearings may provide a high axial load-carrying capacity. The bearings may accommodate high speeds and rapid accelerations; and offer high operating accuracy. The bearings may provide radial and axial support. The bearings may provide extremely precise axial guidance of the longitudinal member (e.g., the screw).

[0013] The bearing assembly may comprise a bearing sleeve. The bearing sleeve may be configured for load transfer. The bearing sleeve may be configured to hold the bearings preloaded.

[0014] In at least some instances, the housing may at least partially seal the actuator. For example, the housing may seal an actuator interior from an actuator exterior. The housing may comprise a cylinder, with the axial movement being along a geometric axis parallel to a central longitudinal geometric axis of the cylinder.

[0015] The screw can be electrically Petition 870260034088, dated April 13, 2026, p. 12 / 135 8 / 55 Operable. The screw may be electrically operable by selectively supplying electrical power to a motor for transmission drive. For example, an electric motor may be associated with the screw of the screw assembly. Rotation of the screw (e.g., at or towards a first end of the screw) may force the threaded part to move axially, parallel to a central longitudinal geometric axis of the screw. The screw may comprise a spline key, such as a screw thread. The threaded part may comprise an interface(s) for engaging the screw, such as an inter-engaging (enveloping) complementary profile. The threaded part may comprise a screw thread(s) for engaging the screw. The threaded part may comprise a threaded part assembly.

[0016] The actuator can be configured to provide an alternative to the valve member. The actuator can be configured to move the valve member in the event of a failure of the screw assembly or a component thereof, or of the primary drive for the same. The actuator can be configured to move the valve member in the event that the screw assembly becomes jammed.

[0017] The actuator may include an override. The override may be configured to enable valve operation without requiring drive transmission from the primary drive. The primary drive may include the drive normally used to operate the screw. The override may be configured to Petition 870260034088, dated 04 / 13 / 2026, page 13 / 135 9 / 55 Release at least one of the screw and threaded portion of the screw assembly. In at least some instances, the override can be configured to enable movement of the screw assembly in unison. The override can be configured to enable movement of the screw assembly as a single unit. For example, the override can be configured to enable axial movement of the screw and threaded portion together. The override can be configured to move, such as translate, the integrity of the screw assembly. The override can be configured to move the screw assembly without triggering or requiring relative movement between the screw and the threaded portion. The override can be configured to enable axial movement of the portion of the screw assembly that is normally axially stationary during normal actuator operation.For example, where the screw is normally stationary, the overlap can be configured to allow axial movement of the screw during the overlap operating mode.

[0018] In at least some instances, the overlay comprises a release mechanism. The release mechanism may be configured to allow movement of at least one of the screw and / or threaded part. The movement may comprise axial movement. The movement may comprise movement not otherwise possible without or prior to the overlay operation. The release mechanism may be configured to allow axial movement of the axially axially oriented member. Petition 870260034088, dated 04 / 13 / 2026, page 14 / 135 10 / 55 stationary, over activation of the override. For example, activation of the override, operation of the release mechanism, may enable axial movement of the screw not normally possible during normal actuator operation.

[0019] The override may comprise a releasable stop. The releasable stop may comprise an axial stop defining or limiting axial movement in at least one direction for at least one of the screw and / or threaded part. The releasable stop may define or limit an axial position of the axially stationary member. The axial stop may comprise a baffle. The axial stop may comprise a bearing baffle (support). Override operation to release the releasable stop may enable movement of the stationary member of the screw assembly not otherwise possible without or prior to override operation. For example, in normal actuator operation, the screw may be axially stationary, with traction rotation of the screw consequently traction axial movement of the threaded part. When actuator override is activated, actuator operation in override mode may enable axial movement of the screw.Accordingly, in at least some instances, the overlap can allow axial movement of both the screw and the threaded part, either in unison or in unison.

[0020] In at least some instances, the releasable stop may comprise a backplate, or at least a portion thereof. The overlapping method may Petition 870260034088, dated 04 / 13 / 2026, page 15 / 135 11 / 55 comprise a release of at least one backplate portion. The backplate portion may be connected to or associated with the screw mounting portion. The release mechanism may comprise a vulnerability, such as a predefined vulnerability. The actuator may be reconfigurable from a normal operating mode to an override operating mode upon activation or breach of the predefined vulnerability.

[0021] The release mechanism can be configured to release the bearing assembly for axial movement. The bearing assembly can normally be axially fixed or limited, such as by the axial stop. Accordingly, overlap operation can enable axial movement of the bearing assembly, such as in conjunction with the longitudinal member. In at least some examples, the overlap is configured to release the bearing housing for axial movement. Accordingly, the bearing housing can be axially movable, such as with the screw, upon activation of the overlap. The bearing housing can be axially stationary during normal operation, such as being stopped by the axial stop.

[0022] The release mechanism can be configured to release the longitudinal member from the bearing assembly. For example, the release mechanism can be configured to allow the longitudinal member to move longitudinally relative to the bearing assembly in overlapping mode. The longitudinal member can be axially immovable relative to the bearing assembly during Petition 870260034088, dated 04 / 13 / 2026, page 16 / 135 12 / 55 Normal actuator operation.

[0023] The release mechanism may comprise an external release interface. The external release interface may be external to the actuator housing, such as a cylinder containing the actuator. The release mechanism may comprise a release member. The release mechanism may comprise an external release member. The external release member may comprise an external sleeve, such as located on an exterior of the actuator housing. Accordingly, the release mechanism may be operated externally from the actuator. The release mechanism may normally be locked in position, such as by a mechanical lock. In at least some examples, the mechanical lock comprises a shear pin. The mechanical lock may be for limiting or preventing movement of the release member, such as in normal actuator use. The shear pin may be detached with screw assembly.The shear pin can be isolated from forces associated with the screw assembly. For example, forces associated with the screw assembly or bearings can consequently be isolated from the shear pin. Accordingly, the shear pin can be prevented from shearing due to movement or force associated with the normal operation of the screw assembly. The shear pin can be sheared by a movement or force applied to an external portion of the actuator. For example, the shear pin can optionally be, or simply be... Petition 870260034088, dated 04 / 13 / 2026, page 17 / 135 13 / 55 sheared by an externally applied force to the releasing limb.

[0024] Different examples may comprise different release mechanisms. In at least some examples, reconfiguration of the actuator from normal operating mode to override operating mode may comprise an irreversible process, or at least one reversible only by resetting and / or recovering at least a portion of the actuator. For example, the actuator may be reconfigurable to override operating mode by activating or breaking the predefined vulnerability. The predefined vulnerability may comprise a shear pin, rupture disc, and / or a portion of another member, such as a thinning or narrowing (e.g., of a portion of the backplate). In other examples, the reconfiguration of the actuator from normal operating mode to override operating mode may be reversible.

[0025] The actuator can be configured for bidirectional operation using the override tool. The actuator can be configured for activation and / or deactivation using the override tool. For example, the actuator can be configured to both open and close the valve using the override tool.

[0026] The actuator may comprise a retainer. The retainer may comprise or be associated with the axial stop. In at least some instances, the retainer holds the axial stop axially during normal actuator operation. Activation of the release mechanism may Petition 870260034088, dated 04 / 13 / 2026, page 18 / 135 14 / 55 comprise a transverse movement of the axial stop or a member associated therewith. The transverse movement may be of the retainer. The retainer may comprise a ring, such as a locking ring. The locking ring may comprise a split locking ring. The retainer may comprise a pretension when mounted on the actuator. For example, the retainer may comprise a transverse pretension, such as radial, when mounted on the actuator. The pretension may assist in maintaining the retainer in its normal retaining position during normal actuator operation. Alternatively, the pretension may assist in releasing the retainer from its normal position when the release mechanism is activated. The retainer may normally be locked in position during normal actuator operation. Overlap may release the retainer.

[0027] The release mechanism can be configured to release the bearing assembly for axial movement. The bearing assembly can normally be axially fixed or limited, such as by the axial stop. Accordingly, the overlap operation can enable axial movement of the bearing assembly, such as in conjunction with the longitudinal member. In at least some examples, the overlap is configured to release the bearing housing for axial movement. Accordingly, the bearing housing can be axially movable, such as with the screw, upon activation of the overlap. The bearing housing can be axially stationary during normal operation, such as being stopped by the axial stop. Petition 870260034088, dated 04 / 13 / 2026, page 19 / 135 15 / 55

[0028] The override may not include a bypass (diversion, secondary passage), such as a bypass for bypassing one or more of the screw and / or threaded part. In at least some instances, the override utilizes at least some functionality of the screw assembly to operate the valve member. The override may utilize the same screw assembly connection for valve member operation in override mode as the screw assembly connection for valve member operation in normal or primary operation, such as without or prior to override operation. The override may enable push-to-push and / or pull-out operation of the valve member as in normal or primary actuator operation. The override may be configured to utilize the interface between the screw and the threaded part of the screw assembly.The override can be configured to utilize the interface between the screw and the threaded part of the screw assembly to directly transmit force and / or motion in the same direction or mode. For example, the override can enable the transfer of axial force and / or axial motion between the screw and the threaded part (e.g., axially pushing / pulling the screw can axially push / pull the threaded part through the screw interface(s) between them). Additionally, or alternatively, the override can be configured to rotate the screw and / or the threaded part. Accordingly, the actuator may not include or... Petition 870260034088, dated 04 / 13 / 2026, page 20 / 135 16 / 55 requires an additional or alternative connection.

[0029] The actuator may comprise an interface for an override tool. The override tool interface may comprise an external interface. The external interface may be axially external to the actuator. For example, where the actuator housing comprises a cylinder, the override tool interface may be provided on or through an axial end of the cylinder. The override tool interface may be positioned with the screw assembly located between the override tool interface and the valve member. The override tool interface may be configured to transmit torque and / or axial force to at least a portion of the screw assembly to move the valve member.The overlay tool interface may comprise a torque interface to enable clockwise and / or counterclockwise torque to be applied to at least one portion of the bolt assembly to move the valve member. The overlay tool interface may be configured to pull at least one portion of the bolt assembly axially in a first direction to push the valve member. Additionally, or alternatively, the overlay tool interface may be configured to pull at least one portion of the bolt assembly axially in a second direction to pull the valve member. The overlay tool interface may be configured to pull at least one portion of the bolt assembly axially to... Petition 870260034088, dated April 13, 2026, page 21 / 135 17 / 55 Open the valve member. Additionally, or alternatively, the overlay tool interface can be configured to pull at least a portion of the rotary screw assembly to open the valve member.

[0030] The overlay tool may comprise an alternative drive. The alternative drive may comprise an electric drive, such as a reciprocating electric motor. Additionally, or alternatively, the alternative drive may comprise a hydraulic drive.

[0031] The overlay tool can be operated remotely. The overlay tool may comprise or be operated by an ROV. Additionally, or alternatively, the overlay tool may be operated manually. In at least some instances, the actuator may be configured for overlay operation by a plurality of overlay tools. For example, the actuator may be configured to be operated by an ROV overlay tool in a first overlay operation, and operated manually in a second overlay operation (e.g., if the first overlay operation was unsuccessful; or if subsequently the first overlay operation was desired to be reversed).

[0032] The actuator may comprise a rotational stop for at least one of the screw and the threaded part. The rotational stop may prevent or at least limit rotation of the axially movable member, at least during normal operation of the actuator. In accordance with Petition 870260034088, dated 04 / 13 / 2026, page 22 / 135 18 / 55 In this way, the rotational stop can provide for conversion of rotation between the screw and the threaded part to axial movement. The axial movement can therefore be pure movement, not linear rotation in the axial direction. The rotational stop may comprise at least one anti-rotation pin. The actuator may comprise a guide member for guiding axial movement of the threaded part and / or the screw. For example, the guide member may comprise a pin in an axial groove. The axial groove may be provided in or associated with the housing; and the guide pin provided in or associated with the threaded part. Alternatively, the axial groove may be provided in or associated with the threaded part.

[0033] The actuator may comprise an underwater or subsea actuator. The actuator may comprise a subsea electric actuator for providing a subsea electric actuation.

[0034] The valve may comprise a subsea valve. The valve may comprise a linear valve, such as a gate valve. The valve may be for selectively providing access through a borehole below an XMT. The valve may be normally closed, such as during normal operation of the XMT. The valve may be selectively opened by actuator operation.

[0035] The screw assembly may comprise a planetary screw assembly, such as a planetary roller screw assembly. The screw assembly may comprise a non-recirculating screw assembly. The lack of axial movement of the screw may mean it does not move axially relative to the Petition 870260034088, dated 04 / 13 / 2026, page 23 / 135 19 / 55 threaded part. The screw assembly may comprise an inverted screw assembly, such as an inverted roller screw assembly. The screw assembly may comprise a reverse screw assembly, such as a reverse roller screw assembly.

[0036] The screw may comprise a recirculating screw, such as a recirculating roller screw. The rollers may move axially within the nut. The rollers may be reset (reset), such as after one orbit around the screw.

[0037] The actuator can be configured for high precision. The actuator can be configured for high speed. The actuator can be configured for heavy load applications. The actuator can be configured for long life applications. The actuator can be configured for heavy-duty applications.

[0038] In at least some examples, the actuator is used as a subsea actuator to provide an axial force to an element. The actuator can be used to operate one or more valves, such as gate valve(s). The valve can be part of an XMT, as well as a vertical XMT. XMT can comprise a Reinforced Vertical Deep Water Tree. The actuator can be used in an all-electric application, such as an all-electric XMT, wellhead, SCM or the like.

[0039] In accordance with an additional aspect, an apparatus comprising the actuator of any other aspect, for example, embodiment or Petition 870260034088, dated April 13, 2026, p. 24 / 135 20 / 55 claim. The apparatus may comprise a subsea apparatus for the oil / gas industry. The apparatus may comprise a wellhead apparatus for access control to a hydrocarbon well. The apparatus may comprise a subsea valve. The apparatus may comprise a subsea control module (SCM). The apparatus may comprise a subsea electronics module (SEM).

[0040] In accordance with an additional aspect, a method of actuation is provided. The method may comprise provision of the actuator of any other example, embodiment, claim or aspect. The method may comprise a method of underwater or submerged actuation. The method may comprise provision of actuation in the apparatus of any other aspect, example, embodiment or claim.

[0041] The method may comprise providing a subsea electric actuator for actuating a valve, the actuator comprising a screw assembly comprising a screw and a threaded part. The screw may comprise a roller screw and the threaded part may comprise a nut. The method may comprise using an axial stop for the actuator to prevent axial movement of the screw and the threaded part, the axial movement being relative to a housing for the screw assembly. The method may comprise providing rotational movement for the screw assembly in a normal operating mode with a primary drive. The method may comprise using the screw assembly to convert the rotational movement to Petition 870260034088, dated 04 / 13 / 2026, page 25 / 135 21 / 55 an axial movement of an actuating member relative to the housing. The method may comprise using an overlap to operate the actuator in an overlap operating mode. The method may comprise releasing at least one of the screw and threaded part for axial movement relative to the housing. The method may comprise axial movement of at least one of the screw and threaded part to move the valve member. The method may comprise axial movement of the screw assembly as in unison, as a single unit, to move the valve member.

[0042] The method may comprise releasing the axial stop to release at least one of the screw and threaded part from axial movement relative to the housing, with the axial stop comprising a barrier preventing axial movement of at least one of the screw and threaded part in normal operation of the actuator. The method may comprise superimposing an electric motor that is used to operate the actuator in normal operating mode. The method may comprise using an alternative drive to operate the actuator in superimposed operating mode.

[0043] The method may comprise operating a valve on a wellhead device for access control to a hydrocarbon well.

[0044] In accordance with an additional aspect, an apparatus is provided that is designed and / or manufactured in accordance with the method of any other aspect, example, embodiment or claim. Petition 870260034088, dated 04 / 13 / 2026, page 26 / 135 22 / 55

[0045] In accordance with a further aspect, at least some examples are provided of an oil / gas apparatus comprising the apparatus of any other aspect, example, embodiment or claim. The oil / gas apparatus may comprise wellhead apparatus, such as a manifold.

[0046] Another aspect of the present disclosure provides a computer program comprising instructions arranged, when executed, to implement a method in accordance with any other aspect, example, claim or embodiment. A further aspect provides machine-readable storage storing such a program. The storage may be non-transient. In at least some examples, the computer program may be for actuator control and / or actuator override.

[0047] In accordance with one aspect of the present invention, computer software is provided which, when executed by a processing resource, is arranged to perform a method in accordance with any other aspect, example, claim or embodiment. The computer software may be stored on a computer-readable medium. The computer software may be tangibly stored on a computer-readable medium. The computer-readable medium may be non-transient. For example, the computer software may be configured to control the actuator and / or its override.

[0048] The present invention includes one or more corresponding aspects, embodiments or features. Petition 870260034088, dated 04 / 13 / 2026, page 27 / 135 23 / 55 in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, it will be readily appreciated that features stated as optional with respect to the first aspect may additionally be applicable with respect to the other aspects without the need to explicitly and unnecessarily list those various combinations and permutations here (e.g., the apparatus of one aspect may comprise features of any other aspect). Optional features as stated with respect to a method may additionally be applicable to an apparatus or device; and vice versa. The apparatus or device of an aspect, example, embodiment, or claim may be configured to perform a feature of a method of any aspect, example, embodiment, or claim.In addition, corresponding features for performing one or more of the functions discussed are also within the present disclosure. It will also be appreciated that features associated with one of the screw and the threaded part can also be associated with the other of the screw and the threaded part. For example, where examples or features are disclosed in combination with the screw, it will be appreciated that those features can apply equally to the threaded part, and vice versa. In at least some examples, the roles of the screw and the threaded part can be reversed (for example, the threaded part can be axially stationary and the screw axially removable, in normal operation, to axially). Petition 870260034088, dated April 13, 2026, p. 28 / 135 24 / 55 move the valve member with the screw).

[0049] It will be appreciated that one or more concretizations / aspects may be useful in at least providing underwater performance.

[0050] The summary above is intended to be merely illustrative and not exhaustive.

[0051] Several respective aspects and features of the present disclosure are defined in the attached patent claims.

[0052] It may be a goal of certain embodiments of this disclosure to solve, mitigate, or highlight, at least partially, at least one or more of the problems and / or disadvantages associated with the state of the art. Certain embodiments or examples may aim to provide at least one of the advantages described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0054] Figure 1 is a schematic cross-sectional diagram of an assembled subsea actuator and associated valve in a normal operating mode;

[0055] Figure 2 shows the underwater actuator of Figure 1 in an overlay operation mode;

[0056] Figure 3 shows a detailed view of a portion of the actuator in Figure 1;

[0057] Figure 4 shows a detailed view of a portion of the actuator in Figure 2; Petition 870260034088, dated 04 / 13 / 2026, page 29 / 135 25 / 55

[0058] Figure 5 is a flowchart showing one method of operation for the actuator in Figure 1;

[0059] Figure 6 is a subsea actuator generically similar to that shown in Figure 1, in a normal operating mode, also showing an overlay tool spaced from the actuator;

[0060] Figure 7 shows the actuator of Figure 6 showing the overlay tool in a first engaged position;

[0061] Figure 8 shows the actuator of Figure 6 with an overlay tool having sheared a shear pin of the actuator;

[0062] Figure 9 shows the actuator of Figure 6, with the overlay tool having partially moved the valve member associated with the actuator;

[0063] Figure 10 shows the actuator of Figure 6, with the overlay tool having completely moved the valve member, from a closed position in Figure 6 to an open position in Figure 10;

[0064] Figure 11 shows a detailed view of the actuator configuration and overlay tool of Figure 6;

[0065] Figure 12 shows a detailed view of the actuator configuration and overlay tool of Figure 7;

[0066] Figure 13 shows a detailed view of the actuator configuration and overlay tool of Figure 8;

[0067] Figure 14 shows a detailed view of the actuator configuration and overlay tool of Petition 870260034088, dated 04 / 13 / 2026, page 30 / 135 26 / 55 Figure 9;

[0068] Figure 15 is a subsea actuator generically similar to that shown in Figure 6, in a normal operating mode, also showing a released tool spaced from the actuator;

[0069] Figure 15a is a detailed view of a portion of Figure 15;

[0070] Figure 16 shows the actuator of Figure 15 with the released tool moved to a first engagement position;

[0071] Figure 16a shows a corresponding detailed view of Figure 16;

[0072] Figure 17 shows the actuator of Figure 15 after operation of the release tool;

[0073] Figure 18 shows the actuator from Figure 17, also showing an overlay tool spaced from the actuator;

[0074] Figure 19 shows the actuator of Figure 18, with the overlay tool engaged with the actuator in a first position;

[0075] Figure 20 shows the actuator of Figure 10, with an advanced overlay tool rod for engaging an actuator interface;

[0076] Figure 21 shows the actuator of Figure 21 with the actuator being operated by the overlay tool to open a valve; and:

[0077] Figure 22 shows the actuator of Figure 21, with the valve operated by the overlay tool, via the actuator, to the fully open position. DETAILED DESCRIPTION OF THE DRAWINGS Petition 870260034088, dated 04 / 13 / 2026, page 31 / 135 27 / 55

[0078] Referring to Figure 1, an actuator (10) is shown in accordance with the present disclosure. Here, the actuator (10) comprises an electrically operable subsea actuator (10) for providing subsea electrical actuation of a valve (16). The actuator (10) comprises a screw assembly (18), here in the form of a roller screw assembly. The screw assembly (18) comprises a screw (20) and a threaded part (22). Here, the roller screw assembly (18) comprises a roller screw (20) and a roller nut (22). The actuator (10) comprises a housing (24) for the roller screw assembly (18); and an axial stop (axial stop) (26) for preventing axial movement relative to the housing (24) of the roller screw (20) and the roller nut (22). The actuator (10) comprises a primary drive for providing a rotational movement for the roller screw assembly (18) in a normal operating mode.The roller screw assembly (18) converts rotational movement to axial movement of a valve member (14) relative to the housing (24). The actuator (10) comprises an override (28) for operating the actuator (10) in an override mode (28) (as shown in Figure 2 and Figure 4). The override (28) is configured to release at least one of the roller screw (20) and roller nut (22) for axial movement relative to the housing (24). In the example shown, the override (28) releases the roller screw (20) for axial movement in the override mode (28).

[0079] The roller screw (20) of the assembly Petition 870260034088, dated 04 / 13 / 2026, page 32 / 135 28 / 55 roller screw (18) herein comprises a longitudinal member in the form of a rigid, solid, threaded rod. The roller nut assembly (22) comprises a plurality of rollers for drive transmission between the screw (20) and the roller nut (22) of the roller screw assembly (18). The transmission converts a rotational motion of the roller screw (20) into a longitudinal motion of the roller nut (22). In other examples (not shown), the roles of the roller nut (22) and the roller screw (20) may be reversed, with the transmission converting a rotational motion of the roller nut (22) into a longitudinal motion of the roller screw (20).

[0080] The roller screw assembly (18) is operable by converting rotational motion or torque, such as from a motor (e.g., electric), into axial motion or force. The axial motion or force is relative to the roller screw (20) and the transmission. Accordingly, operation of the roller screw (20) provides an axial movement of the roller nut (22) relative to the roller screw (20). The axial movement here comprises linear movement [e.g., the roller nut (22) from right to left or from left to right, as shown in [Figure 1 and Figure 2]. Here, the roller screw assembly (18) defines a linear actuator. The actuator (10) comprises a motor, which is the primary drive for operation of the actuator (10) in normal operating mode, as shown in Figure 1 and Figure 3. Petition 870260034088, dated 04 / 13 / 2026, page 33 / 135 29 / 55

[0081] The roller screw assembly (18) is operable to selectively axially pull the valve (16) cyclically between open and closed positions. For example, the roller screw assembly (18) is operable to push the valve member (14) into an open position (shown in Figure 1) and to pull the valve member (14) into a closed position [similar to the valve member position (114) shown in a closed configuration in Figure 6]. The roller screw assembly (18) comprises a push tube (30).

[0082] The valve (16) herein has a valve stem or rod (12). The valve stem (12) extends through a stem seal (32) housed in a bonnet (34). The valve member (14) comprises a bore sealing member, the bore sealing member being configured to sealably occlude access through a bore (36). The bore (36) herein is for provision of access below an XMT (not shown), such as when an XMT is removed, damaged, inspected or repaired, etc. The valve (16) comprises a seat (38) for the bore sealing member. As shown herein, the valve (16) is a gate valve. The valve stem (12) is perpendicular to the bore (36), with the valve stem (12) being axially movable along its geometric axis perpendicular to the bore (36).In accordance with this, the hole sealing member (14) is transversely movable into and out of the hole (36) to respectively close and open the hole (36) [e.g., for access through the hole (36)].

[0083] At least one of the screw and nut of Petition 870260034088, dated 04 / 13 / 2026, page 34 / 135 30 / 55 roller (22) of the roller screw assembly (18) is operatively associated with the valve member (14). Here, the roller nut (22) is connected to the valve member (14) in such a way that axial movement of the roller nut (22) axially moves the valve member (14). In other examples (not shown), the screw is connected to the valve member (14) in such a way that axial movement of the screw axially moves the valve member (14). The roller nut (22) is connected to the push tube (30), the roller nut (22) being the axially movable member of the roller screw assembly (18) in normal operating mode (as shown in Figure 1 and Figure 3). The roller screw (20) is the axially stationary member of the roller screw assembly (18) as shown here, at least during normal or primary operation of the actuator (10).The push tube (30) is configured to push the valve stem (12) and also to pull the valve stem (12), with the push tube (30) here being tied to the valve stem (12).

[0084] The actuator (10) comprises a housing (24) configured to maintain an axial position of the axially stationary roller screw assembly member (18). Here, the housing (24) comprises an axial stop (26) for maintaining the axial position of the roller screw (20), the axial stop (26) preventing axial movement of the axially stationary roller screw in a first axial direction – to the right, towards the valve (16), as shown in Figure 1. Here, a back plate (40) at the rear of the housing (24) prevents axial movement of the Petition 870260034088, dated 04 / 13 / 2026, page 35 / 135 31 / 55 roller screw (20) in a second axial direction - to the left, away from the valve (16), as shown in Figure 1. The axial directions are parallel to the longitudinal geometric axis of the roller screw (20). The housing (24) limits or prevents axial movement of the roller screw (20) during normal operation of the actuator (10). Accordingly, here, the actuator (10) is normally operable to actively rotate, driven by the motor, the roller screw (20) to axially displace the roller nut (22), thereby axially displacing the valve member (14) associated with the roller nut (22).

[0085] The actuator (10) comprises bearing assembly (42) comprising a bearing housing (44) containing contact angle bearings (46) for supporting the roller screw (20). The bearings (46) provide a high degree of axial rigidity, high axial load carrying capacity, accommodate high speeds and rapid accelerations, and offer high operating precision. The bearings (46) provide secure radial support and extremely precise axial guidance of the roller screw (20).

[0086] Here, the housing (24) seals the actuator (10), with an interior of the actuator (10) sealed from an exterior of the actuator (10). The housing (24) here comprises a cylinder, with an axial movement of the roller nut (22) being along a geometric axis parallel to a central longitudinal geometric axis of the cylinder.

[0087] The roller screw (20) is electrically operable. The roller screw (20) is electrically Petition 870260034088, dated 04 / 13 / 2026, page 36 / 135 32 / 55 operable by selectively supplying electrical power to the motor for drive transmission. Here, the electric motor is associated with the screw (20) of the roller screw assembly (18). Rotation of the screw (20) (e.g., at or towards a first end of the screw) forces the roller nut (22) to move axially, parallel to the central longitudinal geometric axis of the screw assembly (18). The screw (20) has a screw thread, with the roller nut (22) comprising a complementary inter-engaging screw thread profile for engaging the roller screw (20).

[0088] The actuator (10) here is configured to provide an alternative actuation for the valve member (14). The actuator (10) is configured to move the valve member (14) in the event of a failure of the roller screw assembly (18) or a component thereof, or of the primary actuation for the same. For example, the actuator (10) is configured to move the valve member (14) in the event that the roller screw assembly (18) becomes jammed.

[0089] The actuator (10) may comprise an override (28), configured to enable operation of the valve (16) without requiring drive transmission from the primary drive (motor) normally used to operate the roller screw (20). The override (28) is configured to release the roller screw (20). In at least some examples, the override (28) is configured to enable movement of the roller screw assembly (18) in unison. For example, the override (28) is configured to enable Petition 870260034088, dated 04 / 13 / 2026, page 37 / 135 33 / 55 Axial movement of the roller screw (20) and roller nut (22) together. The overlay (28) is configured to enable axial movement of the portion of the roller screw assembly (18) that is normally axially stationary during normal operation of the actuator (10). For example, where the roller screw (20) is normally axially stationary in normal operating mode as shown in Figure 1, the overlay enables the roller screw (20) to move axially in overlay operating mode, as shown in Figure 2 and Figure 4.

[0090] Here, the overlay (28) comprises a release mechanism (50) configured to enable axial movement of the roller screw (20) which is not otherwise possible without or prior to the operation of the overlay (28). The release mechanism (50) is configured to enable axial movement of the roller screw (20) not normally possible during normal operation of the actuator (10), upon activation of the overlay (28), as shown in Figures 1 - 4.

[0091] The overlay (28) herein comprises a releasable axial stop (26) defining or limiting axial movement in at least one direction for the roller screw (20). Herein, the axial stop (26) comprises a bearing housing. Operation of the overlay (28) to release the releasable stop enables movement of the stationary member of the roller screw assembly (18) not otherwise possible without or prior to operation of the overlay (28). In normal operation of the actuator (10) the roller screw (20) is Petition 870260034088, dated 04 / 13 / 2026, page 38 / 135 34 / 55 axially stationary, with traction rotation of the roller screw (20) consequently driving axial movement of the roller nut (22). As shown in Figure 2 and Figure 4, when the actuator override (28) is activated, operation of the actuator (10) in override mode (28) enables axial movement of the roller screw (20). In accordance with this, here, the override (28) can enable axial movement of both the roller screw (20) and the roller nut (22), such as in tandem (together) or unisonance.

[0092] The release mechanism (50) is configured to release the bearing assembly (42) for axial movement, the bearing assembly (42) normally being axially fixed or limited by the axial stop (26) in the form of the bearing guard. In accordance with this, operation of the override (28) enables axial movement of the bearing assembly (42) together with the roller screw (20). Here, the override (28) is configured to release the bearing housing (44) for axial movement with the roller screw (20), upon activation of the override (28). As shown in Figure 1 and Figure 3, the bearing housing is axially stationary during normal operation, being stopped by the axial stop (26).

[0093] In other examples, the release mechanism (50) releases the roller screw (20) from the bearing assembly (42). For example, the release mechanism (50) in such examples is configured to enable the roller screw (20) to move longitudinally relative to a Petition 870260034088, dated 04 / 13 / 2026, page 39 / 135 35 / 55 bearing mounting (42) in overlapping mode (28). The roller screw (20) is axially immovable relative to the bearing mounting during normal actuator operation (10).

[0094] The release mechanism (50) herein comprises an external release interface, external to the actuator housing (24). The release mechanism (50) comprises an external release sleeve (52) located on an exterior of the actuator housing (10). Accordingly, the release mechanism (50) is operated externally to the actuator (10). The release mechanism (50) is normally to be locked in position by a mechanical lock, comprising a shear pin (54) herein for limiting or preventing movement of the external release sleeve (52) in normal use of the actuator (10). The shear pin is dissociated from the roller screw assembly (18), being isolated from forces associated with the roller screw assembly (18).Here, forces associated with the roller screw assembly (18) and bearings (46) for the same are isolated from the shear pin (54) by one or more bearings / balls (56) providing an interface between the outer release sleeve (52) and the roller screw assembly (18) and bearings (46) for the same. Accordingly, the shear pin (54) is prevented from shearing due to movement or force associated with the normal operation of the roller screw assembly (18). The shear pin (54) is only sheared by a movement or force applied externally to the outer release sleeve. Petition 870260034088, dated 04 / 13 / 2026, page 40 / 135 36 / 55 (52). The bearing(s) / balls (56) provide for low axial friction (rolling) for sliding motion during release of the outer release sleeve (52), while providing a rigid or stiff radial connection between the outer release sleeve (52) and the roller screw assembly (18).

[0095] Here the actuator (10) comprises a retainer (58) associated with the axial stop (26), the retainer (58) retaining the axial stop (26) axially during normal operation of the actuator (10). Activation of the release mechanism (50) introduces a transverse movement of the retainer (58). Here the retainer (58) comprises a split locking ring. The retainer (58) comprises a pre-tension when mounted on the actuator (10). Here the retainer (58) comprises a transverse, radial pre-tension when mounted on the actuator (10). The pre-tension assists in releasing the retainer (58) from its normal position when the release mechanism (50) is activated. The retainer (58) is normally locked in position during normal operation of the actuator (10), with the overlay (28) releasing the retainer (58).As can be seen in Figure 3 and Figure 4, when the external release sleeve (52) is released (moved from left in Figure 3 to right in Figure 4), a cavity (60) is advanced to the axial position of the bearing(s) / balls (56), enabling the bearing(s) / balls to be pushed radially outwards with the retainer (58), thereby releasing the axial stop (26) for axial movement in overlap mode as shown in Figure 4. A deflection angle (62) assists transverse release of the retainer (58). Petition 870260034088, dated 04 / 13 / 2026, page 41 / 135 37 / 55

[0096] Here, the overlay (28) does not comprise a bypass (detour, secondary passage), such as a bypass for bypassing one of the roller screw (20) and / or the roller nut (22). The overlay (28) utilizes at least some functionality of the roller screw assembly (18) to operate the valve member (14) in overlay operating mode. The overlay (28) here utilizes the same connection of the roller screw assembly (18) to the valve member (14) for operating the valve assembly (16) in overlay mode insofar as the connection of the roller screw assembly (18) to the valve member (14) for operating the valve assembly (16) in normal or primary operation previously for operating the overlay (28). The overlap (28) enables the same push tube (30) to operate for pushing and / or pulling the valve member (14) as in normal or primary actuator operation (10).The overlap (28) is configured to utilize the interface between the roller screw (20) and the roller nut (22) of the roller screw assembly (18) to directly transmit force and / or motion in the same direction or mode. For example, the overlap (28) enables the transfer of an axial force and / or axial motion between the roller screw (20) and the roller nut (22) [e.g., axially pushing / pulling the roller screw (20) which axially pushes / pulls the roller nut (22) through the threaded interface(s) between them]. Additionally, the overlap (28) is configured to rotate the roller screw (20). Accordingly, the actuator (10) does not comprise or. Petition 870260034088, dated April 13, 2026, page 42 / 135 38 / 55 requires an additional or alternative connection between the roller screw assembly and the valve member.

[0097] The actuator (10) comprises an external interface (70) for an axially external overlay tool (not shown) to the actuator (10). Herein, where the actuator housing (24) comprises a cylinder, the overlay tool interface (70) is provided on or through an axial end of the cylinder. The overlay tool interface (70) is positioned with the roller screw assembly (18) located between the overlay tool interface (70) and the valve member (14). The overlay tool interface (70) is configured to transmit torque and / or axial force to the roller screw (20) to move the valve member (14). Herein, the overlay tool interface (70) comprises a torque interface to enable clockwise and / or counterclockwise torque to be applied to the roller screw (20) to move the valve member (14).The overlay tool interface (70) is configured to pull the roller screw (20) axially in the first direction to push the valve member (14). Additionally, the overlay tool interface (70) is configured to pull the roller screw (20) axially in the second direction to pull the valve member (14). The overlay tool interface (70) is configured to pull the roller screw (20) axially to open and close the valve member (14). Additionally, the overlay tool interface (70) is configured to pull at least one portion. Petition 870260034088, dated 04 / 13 / 2026, page 43 / 135 39 / 55 of the roller screw assembly (18) rotationally to open and close the valve member (14). Here, it will be appreciated that the roller screw (20) was axially and rotationally pulled from the position in Figure 1 to the position in Figure 2, thereby axially moving the roller screw (20) relative to the roller nut (22). It will be appreciated that the roller screw (20) can be pulled further (e.g., to the right in Figure 2). After that, it may be possible to close the valve (16) by actuating the roller screw assembly (18) in an opposite direction (e.g., to the left from the position shown in Figure 2) to pull the valve member (14) closed (to the left from the position shown in Figure 2). The overlay tool [not shown, but may be generically similar to that (190) shown in Figure 6] comprises an alternative drive, such as a hydraulic drive.

[0098] The overlay tool is operated remotely, by an ROV. In at least some examples, the actuator (10) is configured for overlay operation by a plurality of overlay tools, such as by an ROV overlay tool in a first overlay operation; and manually operated in a second overlay operation (for example, if the first overlay operation was unsuccessful; or if subsequently the first overlay operation was desired to be reversed).

[0099] Here, the actuator (10) comprises a rotational stop (80) for the roller nut (22) to prevent Petition 870260034088, dated 04 / 13 / 2026, page 44 / 135 40 / 55 or at least limit rotation of the roller nut (22), during normal operation and overlapping of the actuator (10). In accordance with this, the rotational stop (80) assists in providing the conversion of rotation between the roller screw (20) and the roller nut (22) to axial movement. The axial movement here is consequently pure movement, not linear rotational movement in the axial direction. The rotational stop (80) here comprises a plurality of anti-rotation pins associated with the roller nut (22), received in axial guide channels (82) associated with the housing (24).

[0100] In at least some examples, the actuator (10) is used as a subsea actuator (10) to provide an axial force to an element. The actuator (10) is used to operate one or more valves (16), such as gate valves (16). The valve (16) may be part of an XMT, as well as a vertical XMT. The XMT comprises a Reinforced Vertical Deep Water Tree. The actuator (10) is used in fully electric applications, such as a fully electric XMT, wellhead, SCM or similar.

[0101] Here, the actuator (10) comprises a subsea electric actuator (10) for providing subsea electric actuation. The valve (16) comprises a subsea gate valve (16) for selectively providing access through the bore (36) below an XMT. The valve (16) is normally closed, as during normal operation of the XMT. The valve (16) can be selectively opened by operating the actuator (10). Here, the roller screw assembly (18) comprises an assembly Petition 870260034088, dated 04 / 13 / 2026, page 45 / 135 41 / 55 planetary roller screw (18). The actuator (10) is configured for high precision. The actuator (10) is configured for high speed. The actuator (10) is configured for heavy load applications. The actuator (10) is configured for long life applications. The actuator (10) is configured for heavy-duty applications. It will be appreciated that the actuator (10) for the valve (16) shown here is part of a subsea wellhead apparatus for access control to a hydrocarbon well.

[0102] Figure 5 represents a method of operating the actuator (10) of Figures 1 to 4. The method comprises providing an actuator (10) of Figure 1 for underwater actuation of the valve (16). The method comprises using the axial stop (26) of the actuator (10) to prevent axial movement of the roller screw (20), the axial movement being relative to the housing (24) for the roller screw (18) mounting. The method comprises providing rotational movement for the roller screw (18) mounting in normal operating mode with the primary drive (electric motor). The method comprises using the roller screw mounting (18) to convert the rotational movement to axial movement of the valve member (14) relative to the housing (24). The method comprises using the overlap (28) to operate the actuator (10) in the overlap operating mode (28).The method comprises releasing the roller screw (20) for axial movement relative to the housing (24). The method comprises axial movement of the roller screw (20) to move the valve member (14) in the mode of. Petition 870260034088, dated 04 / 13 / 2026, page 46 / 135 42 / 55 overlapping operation.

[0103] The method comprises releasing the axial stop (26) to release the roller screw (20) for axial movement relative to the housing (24), with the axial stop (26) comprising the stop preventing axial movement of the roller screw (20) in normal operation of the actuator (10). The method comprises overriding the electric motor that is used to operate the actuator (10) in normal operating mode. The method comprises using an alternative drive to operate the actuator (10) in overriding operating mode (28). The method comprises operating the valve (16) of the wellhead apparatus for access control to a hydrocarbon well.

[0104] It will be appreciated that in the unlikely event that a portion of the actuator (10) fails, the overlay (28) may enable operation of the valve (16).

[0105] Figure 6 shows a further embodiment of an actuator (110) generically similar to that shown in Figures 1 to 4. The actuator (110) of Figure 6 shares common features with the embodiment of Figure 1, with those features represented by reference numerals incremented by 100. For example, the actuator (100) comprises a roller screw assembly (118) with a roller screw (120) and a roller nut (122). Not all features common to both embodiments are repeated here for brevity and clarity. Operation of the actuators (10, 110) is generically similar, with possible overlap by Petition 870260034088, dated 04 / 13 / 2026, page 47 / 135 43 / 55 an overlay tool.

[0106] As with the actuator (110), an exemplary overlay tool (190) is also represented in Figure 6. The overlay tool (190) is configured to engage with the overlay tool interface (170) at the axial end of the cylinder, as shown in the transition from Figure 6 to Figure 7. In Figure 7, the overlay tool (190) is shown here with a pair of arms (192a, 192b) positioned around an exterior of the cylindrical actuator housing (124). Each of the overlay tool arms (192a, 192b) comprises an internal protrusion (193a, 193b) for engaging the external release sleeve (152) of the actuator (110). As shown in Figure 7, the overlay tool was slid over (along the) housing (120) (towards the right) from the positions in Figure 6.It will be appreciated that the protrusions (193a, 193b) can be positioned beyond the outer release sleeve (152) due to bending of the overlapping tool arms (192a, 192b) as the protrusions (193a, 193b) run over (along the) outer release sleeve (152). In other examples, the protrusions (193a, 193b) can be positioned beyond the outer sleeve (152) (to the right as shown in Figure 7) by rotating the overlapping tool arms (192a, 192b) to align with castellations or slots in the outer release sleeve (152) before rotating to align the protrusions (193a, 193b) with corresponding protrusions in the outer release sleeve (152). It will also be appreciated that in other embodiments the overlapping tool... Petition 870260034088, dated 04 / 13 / 2026, page 48 / 135 44 / 55 may comprise more or fewer arms for engaging the external release sleeve (152). For example, in other embodiments, there may be a single arm; or the overlay tool (190) may comprise a sleeve extending completely around the external release sleeve (152). It will also be appreciated that in addition to, or instead of, arms for pulling, an overlay tool may have a sleeve or arms for pushing the external release sleeve, such as the external release sleeve (52) shown in Figure 1.

[0107] With the overlay tool (190) positioned as shown in Figure 7, the external release sleeve (152) can be operated - here by pulling on the arms (192a, 192b). It will be appreciated that the arms (192a, 192b) can be controlled to operate the sleeve (152) by applying a force such as from a cylinder or piston. For example, here pressurizing a chamber (194) (shown here as an annular chamber) can force movement of a piston (195) to force the arms (192a, 192b) to operate the sleeve (152). The piston (195) here divides a volume defined by an overlapping tool cylinder (191) into two chambers (194, 198). As shown in the transition between Figure 7 and Figure 8, the shear pin (154) is configured to shear in a force exerted by the arms (192a, 192b) of the overlay tool (190) - pulling the release sleeve (152) to the left as shown in Figure 8 to shear the pin (154) [while the sleeve (52) can be pushed to the right in the transition between Figure 1 and Figure 2, and Figure 3 and Figure 4, to shear the shear pin]. Petition 870260034088, dated 04 / 13 / 2026, page 49 / 135 45 / 55 54]. It will be appreciated that the overlay tool (190) can be hydraulically operated, such as by supplying or pressurizing hydraulic fluid into / to the chamber (194) to move the outer release sleeve (152) to shear the shear pin (154). It will also be appreciated that other actuation methods can be used to shear the shear pin (154), such as pressurizing other chambers [for example, in some embodiments an inner overlay tool chamber (196) can be pressurized] or other actuation means, such as electrically operated or even manual. A detailed view of the shear pin can be seen in Figures 12 to 13. In the embodiment shown here, the external release sleeve (152) comprises a cavity (160) which becomes aligned to release the axial stop (126) as illustrated in Figures 13 to 14.

[0108] With the external release sleeve (152) released by the overlay tool (190), as shown in Figure 8 (and Figure 13), the axial stop (126) can be released, similarly as for the actuator (10) in Figure 4. The cavity (160) is advanced to the axial position of the bearing(s) / balls (156), enabling the bearing(s) / balls to be pushed radially outwards with the retainer (158), thereby releasing the axial stop (126) for axial movement of the roller screw assembly (118) in overlay mode as shown in Figure 4. Here, an angle (162) in the axial stop (126) supports transverse release of the retainer (58). The angle (162) is configured to Petition 870260034088, dated 04 / 13 / 2026, page 50 / 135 46 / 55 assists in transverse movement of the retainer (158) away from the axial stop (126) when the retainer is applied in an axial direction – the axial direction being that of the actuator (110), with the transverse direction here being perpendicular to it. The angle is not a right angle; here the angle (162) is defined by a face of the axial stop (126) that is inclined backward (to the left in Figure 13) by a few degrees. Accordingly, the angle (162) is a small acute angle of a few degrees for a radial transverse access (110); and defines an obtuse opening of a few degrees more than 90 degrees between a side face (e.g., cylindrical outer side wall) of the axial stop (126). It will be appreciated that in other embodiments other interface configurations between the axial stop (126) and the retainer (158) can be provided.For example, the retainer (158) may comprise a deflection angle to assist transverse movement of the retainer (158) resulting from an applied axial force [such as by the axial stop (126)]. With the cavity (160) aligned with the bearing(s) / balls (156), the bearing(s) / balls (156) are free to move axially outwards into the cavity (160), as when applied by the retainer (158) - and represented in the transition from Figure 13 to Figure 14. Accordingly, when the retainer (158) is applied radially outwards via the angle (162) by an axial force applying the axial stop (126), the retainer (158) is no longer prevented from radial movement by the external release sleeve (152) [via the bearing(s) / balls (156)]. Petition 870260034088, dated 04 / 13 / 2026, page 51 / 135 47 / 55 in the overlapping configuration of Figure 13 and Figure 14 (and Figures 8 to 10), as opposed to the normal operating configuration of the actuator (110) of Figure 11 (and Figure 7). Accordingly, the retainer (158) can be released by the overlapping tool (190), releasing the axial stop (126), consequently enabling axial movement of the roller screw assembly (118) as shown in Figures 9, 10 and 13. It will be appreciated that the axial stop (126) and / or the retainer (158) can be circumferential (e.g., rings here). Although only a single set of bearings / balls (156) is shown in cross-section in the Figures, it will be appreciated that multiple sets (e.g., shaft) can be spaced circumferentially around the actuator (110).

[0109] As shown here in Figure 8, once the outer release sleeve (152) has been actuated to shear the shear pin (154), further movement of the outer release sleeve (152) is limited. For example, further movement here is prevented from the position shown in Figure 8 [e.g., by a stop or stop (197), such as associated with the back plate (140) or housing (142)]. Accordingly, further pressurization of the chamber (194) here does not move the arms (192a, 192b) or outer release sleeve (152) further from the position in Figure 8. As shown from the transition from Figure 8 to Figure 9, further pressurization of the chamber (194) causes the piston (195) to move (further) relative to the housing. Petition 870260034088, dated April 13, 2026, page 52 / 135 48 / 55 overlapping tool cylinder (191). The piston (195) is connected to a tool rod (199) which is connected to and engages the actuator overlapping tool interface (170). Accordingly, as shown in Figure 9, axial movement of the piston (195) causes axial movement of the tool rod (199), here a rod, and actuation of the actuator (110) via the actuator overlapping tool interface (170), as described in detail below.

[0110] With the axial stop (126) released as described above and shown in Figure 13, the roller screw assembly (18) is no longer prevented from axial movement as a unit. In the example shown here, the bearing assembly (142), including the bearing housing (144), is released for axial movement by the actuation of the external release sleeve (152). The application of force from the actuator tool (190), here via the overlapping tool interface (170) and the tool rod (199) pulled by the piston (195), pulls the integrity of the roller screw assembly (118), including the bearing assembly (142), axially. Accordingly, even in the event of failure of the roller screw assembly (118) or a component thereof, the overlapping tool (190) can be used to operate the valve member (114).The valve member (114) can be operated between the closed position (e.g., in Figure 8) and the open configuration (e.g., in Figure 10). It will be appreciated that the embodiment shown in Figures 8 to 10 has a roller screw assembly. Petition 870260034088, dated April 13, 2026, page 53 / 135 49 / 55 (118) being pushed in unison as a single unit to move the valve member (114) to the open position. Accordingly, it is only necessary for the overlay tool (190) to contact the overlay tool interface (170) to push the roller screw assembly (118); and not necessarily to grip the overlay tool interface (170). However, it will also be appreciated that where the overlay tool (190) engages the overlay tool interface (170) to grip the overlay tool interface (170), the roller screw assembly (118) can additionally be pulled [e.g., to close the valve by pulling the valve member (114) from the position in Figure 10 to the position in Figure 8].Similarly, in at least some examples, it will also be appreciated that the overlay tool (190) can engage the overlay tool interface (170) to apply torque to the overlay tool interface (170). Accordingly, in at least some examples, the overlay tool (190) can be used to rotate the roller screw assembly (118), or a component thereof (such as the roller screw). Such rotation can be used to axially move at least one component of the roller screw assembly (118), or assist therein.

[0111] Figure 15 shows a further embodiment of an actuator (210) generically similar to that (110) shown in Figures 6 to 14. The actuator (210) of Figure 6 shares common characteristics with the Petition 870260034088, dated April 13, 2026, page 54 / 135 50 / 55 embodiment (110) of Figure 6, with those features represented by the reference numerals incremented by 100. For example, the actuator (200) comprises a roller screw assembly (218) with a roller screw (220) and a roller nut (222). Not all features common to both embodiments are repeated here for brevity and clarity. Operation of the actuators (110, 210) is generally similar, with overlap possible by an overlapping tool.

[0112] The example (210) shown here does not comprise an external release sleeve, in contrast to that (152) of Figure 6. As shown in Figure 15, and in detail in Figure 15a, the actuator (210) is configured for release of the bearing assembly (210) by release of an axial stop, here the back plate (240). In accordance with this, similar to the previous examples of actuator (210) overlay {as shown here, also comprised in an actuator linear drive module (ALDM)}, the overlay method involves release of the roller screw assembly (218) by release of the bearing assembly (242). The back plate (240) has a predefined vulnerability in the form of a recess (241), as shown in detail in Figure 15a.It will be appreciated that the recess (241) extends around the entire circumference of the backplate (240) in the example shown; although in other examples partial recesses, or multiple discrete recesses, may be used. As shown in Figure 15a, the recess is supported – here with a pair of half-rings (243) if. Petition 870260034088, dated April 13, 2026, page 55 / 135 51 / 55 extending around in the annular space provided by the recess (241). The back plate (240) here has a guide groove (notch) (245). The guide groove (245) assists in positioning a release tool (247), shown here as a core drill. As shown in Figure 16, and in detail in Figure 16a, an inner wall (249) of the ROV bucket also assists in guiding and supporting the release tool (247). The release tool (247) can be used to release the bearing assemblies (242) by releasing the back plate (240) – shown in Figure 16 – by rotating the core drill of the release tool (27) to cut into the back plate (240), guided by the guide groove (245). As shown here, the bearing assembly (242) has a bearing sleeve (244) configured to transfer loads and keep the supports (26) preloaded.

[0113] As shown in Figure 17, the core drill of the release tool (247) only needs to penetrate the back plate (240) to the recess (241). Although shown here as having an internal diameter corresponding to the core drill of the release tool (247) [and the groove guide (245)]. It will be appreciated that in other examples, the recess (241) may extend to a smaller diameter – such as to allow for additional tolerance in the positioning and / or cutting of the core drill of the release tool (247). Once the back plate (240) has been cut by the core drill of the release tool (247) as far as the recess (241), the bearing assembly (242) is released relative to the housing (224) – along with a Petition 870260034088, dated 04 / 13 / 2026, page 56 / 135 52 / 55 inner portion of the back plate (240) which is further tied for bearing mounting (242).

[0114] Once the release tool (247) has released the bearing assembly (242), as shown in the configuration of Figure 17, the actuator (210) is in a configuration generally similar to that shown in Figure 2 and Figure 8 - with the roller screw assembly (218) capable of axial movement as a unit together with the bearing assembly (242). With the back plate (240) released as described above and shown in Figure 16, the roller screw assembly (218) is no longer in any way prevented from axial movement as a unit.In the example shown here, the bearing assembly (242), including the bearing sleeve (244), is fed for axial movement by the cut of the back plate (240). It will be noted here that where the axial stop (226) normally prevents axial movement of the bearing assembly (242) [and roller screw assembly (218)], the valve side axial stop (226) is connected to the back plate (240) in such a way that release of the central portion of the back plate (240) also releases the axial stop (226) at the other end of the bearing assembly (218). In accordance with this, as shown sequentially in Figure 18 through Figure 22, an overlay tool (290) can be used to engage the external interface (270) of the actuator (210) to control the valve (216) with the actuator (210). As shown in Figure 19, the overlay tool (290) has a tool shank (299) that can be extended to engage the. Petition 870260034088, dated 04 / 13 / 2026, page 57 / 135 53 / 55 external interface (270), as shown in Figure 20 - with the actuator (210) and the overlay tool (290) in portions generally similar to those shown in Figure 8.

[0115] In accordance with this, pressurization of the chamber (294) causes the piston (295) connected to the tool rod (299) to move relative to the overlapping tool cylinder housing (291). As shown in the transition from Figure 20 to Figure 21, axial movement of the piston (295) (to the right as shown) causes axial movement of the tool rod (299), here a rod, and actuation of the actuator (210) via the actuator-overlap tool interface (270).

[0116] The application of force from the actuator tool (290), here by means of the overlapping tool interface (270) and the tool rod (299) pulled by the piston (295), pulls the integrity of the roller screw assembly (218), including the bearing assembly (242), together with the central portion of the back plate (240), axially. Accordingly, even in the event of failure of the roller screw assembly (218) or component or control thereof, the overlapping tool (290) can be used to operate the valve (216). The valve member (214) can be operated between the closed position (e.g., in Figure 16) and the open configuration (e.g., in Figure 22). It will be appreciated that the embodiment shown in Figures 18 to 22 has the roller screw assembly (218) being pushed in Petition 870260034088, dated April 13, 2026, page 58 / 135 54 / 55 unison as a single unit to move the valve member (214) to the open position. Accordingly, it is only necessary for the overlay tool (290) to contact the overlay tool interface (270) to push the roller screw assembly (218). However, it will also be appreciated here that the overlay tool (290) can engage the overlay tool interface (270) to grip the overlay tool interface (270), such that the roller screw assembly (218) can also be pulled [for example, to close the valve (216) by pulling the valve member (214) from the position in Figure 22 to the position in Figure 16].

[0117] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being realized on the basis of the present patent application as a whole in the light of the common general knowledge of a person skilled in the art, regardless of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the patent claims.

[0118] The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. It should be understood that the embodiments described herein are merely illustrative and that various Petition 870260034088, dated 04 / 13 / 2026, page 59 / 135 55 / 55 modifications may be made to the same without departing from the scope or spirit of the present invention. For example, it will be appreciated that although shown here as a screw comprising a continuous screw thread, in other embodiments the longitudinal member of the roller screw assembly may comprise an interface or profile for inter-engagement (interaction) (e.g., screw thread(s), spindle(s)) in only one or more portions of the longitudinal member (e.g., one or more axial zones). Similarly, where a roller screw assembly is shown in exemplary embodiments, other embodiments may comprise other screw arrangements, such as with an ACME screw, ball screw, lead screw (main screw) or the like. Petition 870260034088, dated 04 / 13 / 2026, pp. 60 / 135

Claims

1 / 6 CLAIMS 1. Subsea electric actuator (10) for providing a subsea electric actuation of a valve (16), the actuator comprising: a screw assembly (18) comprising a screw (20) and a threaded part (22) for receiving the screw; a housing (24) for the screw assembly (18); an axial stop (26) for preventing axial movement relative to the housing (24) of at least one of the screw (20) and the threaded part (22); a primary drive for providing a rotational movement to the screw assembly (18) in a normal operating mode, the screw assembly (18) converting the rotational movement to an axial movement of a valve member (14) relative to the housing (24);an overlay (28) for operating the actuator in an overlay operating mode, the overlay being configured to release at least one of the screw (20) and the threaded part (22) for axial movement relative to the housing (24), characterized in that the screw (20) comprises a roller screw and the threaded part (22) comprises a roller nut, and the overlay (28) is configured to release the axial stop (26) to release at least one of the roller screw and the roller nut for axial movement relative to the housing (24).

2. Actuator, according to claim 1, Petition 870260034088, dated 04 / 13 / 2026, page 61 / 135 2 / 6 characterized in that the axial stop (26) comprises a baffle, the baffle preventing the axial movement of at least one of the screw (20) and the threaded part (22) in normal operation of the actuator, optionally the axial stop (26) comprises a back plate, the back plate preventing the axial movement of at least one of the screw (20) and the threaded part (22) in normal operation of the actuator.

3. Actuator, according to claim 1 or 2, characterized in that the actuator comprises a bearing assembly (42) for supporting a portion of the screw assembly (18), and the overlay (28) is configured to release a portion of the bearing assembly for axial movement in the overlay operating mode.

4. Actuator, according to any of the preceding claims, characterized in that it is the screw that is prevented from axial movement relative to the housing (24) by the axial stop (26) and the threaded part converts the rotational movement into axial movement, preferably the threaded part is prevented from rotating relative to the housing (24) with axial movement of the threaded part relative to the housing being guided by a guide member, and the threaded part is connected by means of a push tube (30) to the valve member, axial movement of the threaded part axially moving the valve member.

5. Actuator, according to any of the preceding claims, characterized in that the overlay (28) is configured to enable an alternative actuation to operate the screw assembly (18) to move the valve member relative to the housing (24), the alternative actuation being alternative to the primary actuation, preferably the actuator comprises an external interface to enable the alternative actuation to be connected externally to the screw assembly (18).

6. Actuator, according to any of the preceding claims, characterized in that the overlap (28) is configured to enable axial movement in both axial directions in the overlap mode, such as pushing and pulling, the valve member.

7. Actuator, according to any of the preceding claims, characterized in that the overlap (28) is configured to enable rotation of at least one of the screw (20) and the threaded part (22).

8. Actuator, according to any of the preceding claims, characterized in that the overlap (28) is configured to enable the application of torque to at least one of the screw (20) and the threaded part (22) for drive rotation of at least one of the screw and the threaded part.

9. Actuator, according to any of the preceding claims, characterized in that the overlay (28) comprises a release mechanism (50), the axial stop (26) defining a releaseable member of the release mechanism, the release mechanism (50) further comprising an external release member Petition 870260034088, dated 13 / 04 / 2026, page 63 / 135 4 / 6 (52), the external release member being accessible on an exterior of the actuator, preferably the external release member comprising an external sliding sleeve, the sleeve being locked during normal operation to prevent sliding movement of the sleeve and becoming unlocked during the overlay mode (28), more preferably the overlay (28) comprising a shear pin (54), wherein the external sliding sleeve is unlocked for the overlay mode by applying a force to the external sliding sleeve to shear the shear pin.

10. Actuator, according to any of the preceding claims, characterized in that the actuator further comprises a retainer (58), the retainer being associated with the axial stop (26), wherein the retainer is configured to move transversely upon activation of the overlap (28) to release the axial stop (26), the transverse movement being transverse to the direction of axial movement of the valve member.

11. Actuator, according to any of the preceding claims, characterized in that the overlay (28) comprises a predefined vulnerability, the predefined vulnerability configured to reconfigure the actuator from a normal operating mode to an overlay operating mode upon activation or disruption of the predefined weakness.

12. Apparatus, characterized in that it comprises the actuator as defined in any of the preceding claims, optionally, the apparatus comprises a wellhead apparatus for accessing a hydrocarbon well.

13. Submarine electric actuation method, characterized by comprising: providing a submarine electric actuator for actuating a valve as defined in any one of claims 1 to 11, the actuator comprising a screw assembly comprising a screw and a threaded part; employing an axial stop of the actuator to prevent axial movement of the screw and the threaded part, the axial movement being relative to a housing for the screw assembly; providing a rotational movement for the screw assembly in a normal operating mode with a primary drive; employing the screw assembly to convert the rotational movement to an axial movement of a valve member relative to the housing;To use an override to operate the actuator in an override operating mode, wherein the override releases at least one of the screw and threaded portion for axial movement relative to the housing, and at least one of the screw and threaded portion is axially moved to move the valve member.

14. Method, according to claim 13, characterized in that it comprises: releasing the axial stop to release at least one of the screw and threaded part for axial movement relative to the housing, with the axial stop comprising Petition 870260034088, dated 04 / 13 / 2026, page 65 / 135 6 / 6 a barrier preventing axial movement of at least one of the screw and threaded part in normal operation of the actuator, and superimposing an electric motor to operate the actuator in normal operating mode, using an alternative drive to operate the actuator in superimposed operating mode.

15. A method according to claim 13 or 14, characterized in that it comprises operating a valve of a wellhead apparatus to control access to a hydrocarbon well, preferably the method comprising activating a release mechanism to reconfigure the actuator to an override operating mode, more preferably the method comprising using a predefined weakness to reconfigure the actuator to override operation. Petition 870260034088, dated April 13, 2026, pp. 66 / 135

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