GB2293185A

GB2293185A - Power-operated equipment

Info

Publication number: GB2293185A
Application number: GB9518739A
Authority: GB
Inventors: Rolf Ruesse
Original assignee: SEABOARD LLOYD Ltd
Current assignee: SEABOARD LLOYD Ltd
Priority date: 1994-09-13
Filing date: 1995-09-13
Publication date: 1996-03-20
Anticipated expiration: 2015-09-13
Also published as: GB2293185B; GB9518739D0; GB9418394D0

Abstract

A remotely operated valve 10 including a power actuator 72. The flow regulator 32 is mounted on the valve bonnet 22 which is locked to the valve body 12 by a latching mechanism 26 - 30. A flow regulator actuating mechanism 44, 62 extends through the bonnet 22 and is coupled to the surrounding actuator hub 78 by a coupling 80 which can be engaged and disengaged by sliding the coupling 80 in and out of the hub 78. The actuator hub 78 is made sufficiently large that the bonnet 22 and attached flow regulator 32 can be fully withdrawn from the valve body 12 without disturbing the actuator 72 or its connections. Valve maintenance is easier and quicker and maintenance equipment is lighter. Reliability is improved and costs are reduced. <IMAGE>

Description

"Power-Operated Equipment" This invention relates to power-operated equipment which is environmentally isolated, and relates more particularly but not exclusively to remotely operated valves.

Fluid-regulating valves which regulate the pressure or flow of fluids in pipes or other conduits are widely employed, for example in the production of gas and/or oil from underwater hydrocarbon fields. For reasons such as safety or convenience, it is common for such valves to be operable by a suitable form of powered actuator, wherein the power is applied or controlled from a location which is remote from the valve. The flow-regulating parts of such valves are exposed to the flowing fluid and may erode quite rapidly, eg if the fluid carries sand or other particulates, and/or if the fluid is corrosive, eg if the fluid contains hydrogen sulphide.

Consequently, the flow-regulating parts of such valves may require frequent replacement.

Examples of such remotely operated flow-regulating valves are the choke valves that are installed on underwater manifolds and christmas trees (wellhead valve clusters). Replaceability of the flow-regulating parts of such underwater choke valves without requiring simultaneous replacement of the entire valve may be achieved by forming the valve with a valve body which is permanently connected to pipes (or other conduits) on either side of the valve, the valve body forming a hollow pressure vessel which is normally closed in a leak-tight and pressure-resistant manner by a valve bonnet which carries the flow-regulating parts of the valve.

These bonnets or valve body closures are usually of considerable size and weight, and therefore require complicated support structures, adequate space, and remote installation/retrieval equipment of considerable size and sophistication.

The power-operated actuator for the flow-regulating parts of the valve may be hydraulic, electrical, or electrohydraulic in nature, or of any other suitable form or combination of forms. If the actuator is secured to the bonnet, the actuator and the bonnet have to be removed together even if (as is usual) only the flow-regulating parts require replacement. Retrieval of the actuator requires disconnection and reconnection of the hydraulic and/or electrical connections for the power and control circuits of the actuator, which actions may be a cause of immediate or subsequent failure. Moreover, the size and weight of typical bonnet/actuator combinations usually preclude their deployment solely by means of an ROV (remotely operated vehicle, ie a remotely controlled submarine with equipment manipulation facilities).

On the other hand, if the actuator is connected into the valve body below the level of the bonnet so as to obviate the need to remove the actuator with the bonnet, an additional primary pressure-containing seal is required, which represents another possible cause of failure.

The above-described remotely operated valve is one special case of a general class to which the invention is applicable, namely power-operated equipment which is environmentally isolated by a pressure vessel or any other form of environmental barrier, with one part of the equipment on the high-pressure or non-environmental side of the barrier, and another part of the equipment (including the powered actuator for the equipment) on the low-pressure or environmental side of the barrier.

The equipment is detachable from the barrier (if necessary, with preliminary isolation) to be withdrawable to the environmental side for repair or replacement of at least those parts of the equipment normally deployed in the non-environmental side of the barrier.

As well as the previously described valve, the equipment may additionally or alternatively comprise equipment other than flow-regulating or pressureregulating valves.

As well as the previously described valve body and bonnet, the environmental barrier may be the general case of a pressure containment. The environmental barrier may additionally or alternatively comprise any other form of barrier, for example radiation shielding surrounding a hot cell into which part of the equipment is deployed for the remote handling of radioactive materials.

According to a first aspect of the present invention there is provided power-operated equipment part of which is environmentally isolated by environmental barrier means in normal operation of the equipment, the barrier means comprising an aperture through which the environmentally isolated part of the equipment is presented to the non-environmental side of the barrier means in normal operation of the equipment, the equipment comprising mounting means by which the equipment may be normally mounted upon the barrier means adjacent the aperture therethrough in a manner to present the environmentally isolated part of the equipment to the non-environmental side of the barrier means, the mounting means being such that the equipment may be selectively dismounted from the barrier means during cessation of normal operation of the equipment and the normally isolated part of the equipment withdrawn through the aperture to the environmental side of the barrier means, the equipment further comprising or being functionally associated with power operation means by which at least the environmentally isolated part of the equipment may be selectively operated, the power operation means being normally mounted upon the barrier means adjacent the aperture therethrough, the arrangement of the aperture, the mounting means, and the power operation means being such that the normally isolated part of the equipment can be selectively withdrawn without dismounting the power operation means.

The power operation means is preferably disposed to lie outwith the path through the aperture along which path the normally isolated part of the equipment is withdrawn, apart from motion coupling means by which equipment-operating output movement of the power operation means is coupled to the normally isolated part of the equipment in use thereof. The power operation means may be disposed to circumscribe the path, or to lie to one side thereof.

The motion coupling means preferably comprises a mechanical coupling partly on the power operation means and partly on the equipment, the parts of the mechanical coupling preferably mutually cooperatively engaging and disengaging automatically upon emplacement and withdrawal of the equipment.

According to a second aspect of the invention there is provided a remotely operated valve comprising a valve body, a valve bonnet, fluid flow regulating means, and actuator means, the valve body comprising a fluid inlet and a fluid outlet, the fluid flow regulating means comprising a control member by which a fluid flow regulator of the regulating means may be selectively actuated, the valve bonnet mounting the fluid flow regulating means such that when the valve bonnet with bonnet-mounted regulating means is operatively secured to the valve body, the fluid flow regulator is disposed within the valve body between the fluid inlet and the fluid outlet to regulate the flow of fluid therebetween, the valve bonnet seals the valve body in a substantially fluid-tight manner other than for selectively regulated flow of fluid between the fluid inlet and the fluid outlet, and the control member is outside the pressure vessel constituted by the mutually sealed combination of the valve body and the valve bonnet, the actuator means being mounted on or adjacent the valve such that when the valve bonnet with bonnet-mounted regulating means is operatively secured to the valve body, the actuator means operatively engages the control member for selective remote operation of the flow regulator, the valve bonnet being withdrawable from the valve body together with the bonnet-mounted regulating means without dismounting the actuator means.

The valve is preferably arranged such that when the valve bonnet with bonnet-mounted regulating means is presented to the valve body to be operatively secured thereto, the actuator means and the control member automatically undergo mutual operative engagement, and vice versa upon withdrawal of the valve bonnet from the valve body. Such mutual operative engagement of the actuator means and the control member is preferably achieved by means of a motion coupling means of which mutually cooperable parts are respectively mounted on the actuator means and the control member. These mutually cooperable parts of the motion coupling means are preferably mutually engagable and disengagable solely by means of the relative movement between the valve bonnet (with bonnet-mounted regulating means) and the valve body during presentation and withdrawal of the bonnet respectively.The actuator means may be formed and disposed so as to surround the control member in use of the valve, the actuator means comprising a central aperture at least sufficiently large to permit the valve bonnet with bonnet-mounted regulating means to be withdrawn from the valve body through the central aperture.

Selective actuation of the fluid flow regulator may be achievable by rotation of the control member about an axis, the actuator means preferably being a rotary actuator disposed to produce rotary movement about a substantially coaxial axis.

The valve may be fitted with projecting guide posts for the docking of maintenance equipment. The guide posts may be anchored in the valve body and the guide post anchorages may also serve to clamp the rotary actuator to the valve body.

Embodiments of the invention will now be described by way of example, with reference to the accompanying drawing, the sole figure of which is a vertical sectional elevation of an embodiment of remotely operated valve in accordance with the present invention.

Referring to the drawing, a remotely operated valve 10 comprises a valve body 12 formed with inlet and outlet ports 14 and 16 which communicate from the exterior of the valve body 12 (in practice, from coupled pipes or conduits which are not shown in the drawing) to the hollow interior of the valve body 12. The top 18 of the valve body 12 is formed with a circular aperture 20 for access to the hollow interior of the valve body 12, for a purpose subsequently detailed.

The aperture 20 is plugged in normal operation of the valve 10 by means of a valve bonnet 22 which is provided with a laterally projecting key 24 which engages a corresponding keyway formed in the aperture 20 to ensure that the bonnet 22 fits into the valve body 12 in one mutual rotational alignment only. When fitted into the aperture 20, the bonnet 22 is locked in position by means of a circumferential array of locking segments 26 which is radially expanded into wedging engagement with an aperture-fitted ring 28 by axial movement of a locking sleeve 30. Details of the locking mechanism 26-30 are set out in GB2277574-A.

The ring 28 is mounted in the aperture 20 by means of a screw thread connection to the valve body 12, such that the axial position of the ring 28, and hence the interaction of the ring 28 with locking segments 26, can be suitably adjusted.

The bonnet 22 mounts a flow regulator 32 of known form to fit inside the follow interior of the valve body 12 when the bonnet 22 is secured in the aperture 20. The regulator 32 acts in normal operation of the valve 10 to regulate the flow of fluid between the inlet and outlet ports 14 and 16, by producing a variable choking effect in known manner utilising sliding axial movement of a choke member 34 relative to a valve seal 36 in the form of an annular sleeve fitted within a normally static regulator body 38. Movement of the choke member 34 is achieved by axial movement of a choke mount 40 whose stem 42 protrudes through the valve bonnet 22 where it is secured to a driven member 44. A sliding key 46 allows the driven member 44 (and hence the choke mount 40 together with the choke member 34) to move axially while preventing the driven member 44 from rotating by any significant extent.Movement of the driven member 44 is achieved by a mechanism which will be detailed subsequently.

The regulator body 38 is secured to the lower end of the valve bonnet 22 by means of a split attachment ring 48. The bonnet 22 and the body 38 are sealed to the interior of the valve body 12 by respective metal-to-metal U-seals 50 and 52. The choke mount 40 and the choke mount stem 42 are slidingly sealed to the bonnet 22 by respective sliding seals 54 and 56.

The choke member 34 and the choke mount 40 (which carries the choke member 34) are axially pressure balanced by end-to-end drillings 58.

The top face of the valve bonnet 22 has a central recess 60 within which a valve stem 62 is mounted for rotational movement about the vertical axis or centreline of the valve 10. The valve stem 62 is restrained against significant axial movement by an annular bush 64 threaded into the upper end of the aperture 60. The lower end of the valve stem 62 has a bore 66 which is internally screw-threaded for cooperation with a matchingly externally screw-threaded upper end 68 of the drive member 44.

Since the driven member 44 can move axially but is restrained against significant rotational movement, the valve stem 62 can rotate but is restrained against significant axial movement, and the driven member 44 is linked to the valve stem 62 by means of the cooperatingly screw-threaded parts 68 and 66 respectively, it follows that rotation of the valve stem 62 about the centreline of the valve 10 causes axial movement of the driven member 44, with consequent axial movement of the choke mount 40 and the choke member 34 carried thereby. Thus rotation of the valve stem 62 causes the choke member 34, in conjunction with the annular sleeve valve seat 36, to present effectively varying sizes of aperture to fluid in its passage between the inlet and outlet ports 14 and 16, thereby functionally actuating the flow regulator 32 of the valve 10.

The valve stem 62 has a squared-off upper end 70 for the attachment of a hand crank (not shown) or other valve operating implement not normally present.

However, for normal operation of the valve 10, a powered rotary actuator 72 is provided. The actuator 72 is generally annular and is clamped to the valve body top 18 by two or more studs 74 and nuts or other actuator locking units 75. The upper ends 76 of the studs 74 are adapted to act as guide posts for the docking of an ROV or other intervention tool (not shown).

The actuator 72 has a hub 78 which is concentric with the centreline of the valve 10. The hub 78 rotates at a suitable (normally low) speed in a selected rotational direction when the actuator 72 is energised under remote control (eg from a surface installation, not shown). Means for coupling rotation of the actuator hub 78 to the valve stem 62 will now be described.

The rotation-coupling means comprises a cup-shaped stem drive sleeve 80 whose lower end hub 82 is coupled to the valve stem 62 by a key 84 sliding in a longitudinal keyway 86 formed along the exterior or the upper half of the stem 62. The key 84 and keyway 86 allow the drive sleeve 80 to slide longitudinally but not rotate with respect to the valve stem 62. A radially projecting ring 88 clamped around the valve stem 62 just below its upper end 70 serves to prevent the slidable sleeve 80 becoming separated from the valve stem 62.

The generally cylindrically periphery of the drive sleeve 80 is fitted with one or more keys 90 dimensioned for longitudinal sliding engagement with a keyway or respective keyways 92 formed in the generally cylindrical inside surface of the actuator hub 78. It is to be particularly noted (for reasons subsequently to be explained) that the inside diameter of the actuator hub 78 (in which the keyway or keyways 92 are formed) is at least as great as the inside diameter of the ring 28 forming part of the bonnet locking mechanism. Consequently, when the locking sleeve 30 is retracted upwards (see below) to allow the locking segments 26 to retract radially inwards under the influence of a garter spring 94 by an extent sufficient to allow the segments 26 to clear the ring 28, the retracted segments 26 will also clear the inside of the actuator hub 78.Since the maximum diameter of the valve bonnet 22 is necessarily limited to a dimension which will also clear the inside of the ring 28, this ensures that the bonnet 22 and all components assembled on it can be withdrawn from the valve body 12 (when the locking segments 26 are retracted) without any need first to detach and remove the actuator 72. This greatly simplifies replacement of the parts of the flow regulator 32 by reducing the number and weight of items to be detached (and subsequently re-assembled), and avoids reducing reliability by leaving actuator power and control connections (not illustrated) undisturbed.

Components assembled on and withdrawn with the unlocked valve bonnet 22 include the flow regulator 32. Since the flow regulator body 38 can be detached from the bonnet 22 simply by opening the split attachment ring 48, the choke member 34 and the valve seat 36 are easily accessible for their replacement by fresh components. Self-alignment on re-assembly is assured by forming the bonnet 22 and the body 38 with a stepped diameter profile dimensioned such that two steps will simultaneously align with complementary profiles inside the valve body 12, so eliminating binding.

Upward retraction of the locking sleeve 30 to initiate detachment of the bonnet 22 from the valve body 12 is achieved by forming the outer (upper) end of the ring 30 with an inturned rim 96 which loosely engages an outwardly rimmed ring 98 secured to the underside of the drive sleeve hub 82. The ring 98 allows the drive sleeve 80 to rotate as required without dragging the locking sleeve 30 around (which would otherwise cause excessive wear to the locking segments 26 and to the sleeve 30 itself) but at the same time the ring 98 ensures that axial movement of the drive sleeve 80 along the centreline of the valve 10 is transmitted to the locking sleeve 30 such that the sleeves 80 and 30 are linked for conjoint axial movement.The drive sleeve 80 can be gripped for axial movement by engagement of the intervention tool (not shown) with a circumferential groove 100 formed around the periphery of the upper end of the drive sleeve 80. The axial sliding movement of the drive sleeve 80 with respect to the valve stem 62 permitted by the key 84 and the keyway 86 allows the drive sleeve 80 to be pulled upwards (and with it, the locking sleeve 30) while the valve bonnet 22 is still locked into the valve body 12.

Similarly, the axial sliding movement of the drive sleeve 80 with respect to the actuator hub 78 permitted by the key(s) 90 and the keyway(s) 92 simultaneously allow the drive sleeve 80 to be pulled upwards (while the valve bonnet 22 is still locked into the valve body 12) while the actuator 72 is still clamped on top of the valve body 12.

In short, by allowing sliding connection/disconnection and by making the actuator hub 78 with an adequately large inside diameter, the valve bonnet 22 and the attached flow regulator 32 can be withdrawn and subsequently re-inserted without disturbing the actuator 72 or its connections.

As already described, the axial position of the ring 28 in the valve body aperture 20 is adjustable by reason of the screw-thread connection of the ring 28 to the valve body top 18. Suitable adjustment of the ring 28 and selection of the original dimensions of the locking sleeve 30 allows for setting up to produce an interference fit between the locking sleeve 30 and the locking segments 26 when the segments 26 are radially extended by axial insertion of the sleeve 30 to lock the valve body 12. This interference fit creates a pre-loaded locking connection and as the contact between the locking sleeve 30 and the locking segments 26 is cylindrical (ie purely radial), there is no pressure-resultant unlocking moment. This situation makes it possible to transfer the bonnet-locking movements as well as actuator-driven valve stem rotation through the stem drive sleeve 80.

Once the valve' bonnet 22 (with attached components) is installed in and locked to the valve body 12, a protective cap 102 is optionally installed over the above-described mechanisms. The cap 102 is located by the guide posts 76 and locked to them by respective nuts or other cap locking units 104. The cap 102 includes a docking profile 106 to allow an ROV-deployed actuator (not shown) to couple directly to the valve stem end 70 for "over-ride" operation of the valve 10.

Actuation of the retrieval (withdrawal) and installation (re-insertion) mechanisms can be achieved by a hydraulically-actuated intervention tool (not shown) designed to interface with the various components (for example, to include radiallycontractable annular jaws to grip the drive sleeve 80 by way of its peripheral groove 100).

As well as the previously described advantages in respect of the invention-enabled ability to refurbish the flow regulator 32 without disturbing the actuator 72, the invention conversely enables the actuator 72 to be separated from the remainder of the valve 10 while leaving the bonnet 22 and the flow regulator 22 undisturbed.

Further advantages of the above-described embodiment of the invention arise from bonnet-locking mechanism being internal to the valve body 12 when in place and locked, thus allowing the valve body 12 to be used for mounting the actuator 72 and the guide posts 76, consequently eliminating complicated prior art support structure as well as assuring accurate alignment of mated tools and vehicles. The internal nature of the bonnet-locking mechanism also reduces the size and weight of the assembly, which reduces the space needed for installation and allows underwater deployment by a remotely operated vehicle, resulting in substantial savings in time and cost. The bonnet-locking mechanism exerts a pre-load which resists separation due to internal pressure and so extends the life of the pressure seals.

While a preferred embodiment has been described with reference to the accompanying drawing, the invention is not restricted to the exact form shown therein.

Modifications and variations can be adopted without affecting the basis of the invention; for example the illustrated fluid flow regulator may be substituted by a flow regulator actuated by rotational movement (eg a ball valve). Other modifications and variations can be adopted without departing from the scope of the invention as defined in the appended claims.

Claims

1. Power-operated equipment part of which is environmentally isolated by environmental barrier means in normal operation of the equipment, the barrier means comprising an aperture through which the environmentally isolated part of the equipment is presented to the non-environmental side of the barrier means in normal operation of the equipment, the equipment comprising mounting means by which the equipment may be normally mounted upon the barrier means adjacent the aperture therethrough in a manner to present the environmentally isolated part of the equipment to the non-environmental side of the barrier means, the mounting means being such that the equipment may be selectively dismounted from the barrier means during cessation of normal operation of the equipment and the normally isolated part of the equipment withdrawn through the aperture to the environmental side of the barrier means, the equipment further comprising or being functionally associated with power operation means by which at least the environmentally isolated part of the equipment may be selectively operated, the power operation means being normally mounted upon the barrier means adjacent the aperture therethrough, the arrangement of the aperture, the mounting means, and the power operation means being such that the normally isolated part of the equipment can be selectively withdrawn without dismounting the power operation means.

2. Equipment as claimed in claim 1 wherein the power operation means is disposed to lie outwith the path through the aperture along which path the normally isolated part of the equipment is withdrawn, apart from motion coupling means by which equipment-operating output movement of the power operation means is coupled to the normally isolated part of the equipment in use thereof.

3. Equipment as claimed in claim 2 wherein the power operation means is disposed to circumscribe the path.

4. Equipment as claimed in claim 2 or claim 3 wherein the motion coupling means comprises a mechanical coupling partly on the power operation means and partly on the equipment, the parts of the mechanical coupling mutually cooperatively engaging'and disengaging automatically upon emplacement and withdrawal of the equipment.

5. A remotely operated valve comprising a valve body, a valve bonnet, fluid flow regulating means, and actuator means, the valve body comprising a fluid inlet and a fluid outlet, the fluid flow regulating means comprising a control member by which a fluid flow regulator of the regulating means may be selectively actuated, the valve bonnet mounting the fluid flow regulating means such that when the valve bonnet with bonnet mounted regulating means is operatively secured to the valve body, the fluid flow regulator is disposed within the valve body between the fluid inlet and the fluid outlet to regulate the flow of fluid therebetween, the valve bonnet seals the valve body in a substantially fluid-tight manner other than for selectively regulated flow of fluid between the fluid inlet and the fluid outlet, and the control member is outside the pressure vessel constituted by the mutually sealed combination of the valve body and the valve bonnet, the actuator means being mounted on or adjacent the valve such that when the valve bonnet with bonnet-mounted regulating means is operatively secured to the valve body, the actuator means operatively engages the control member for selective remote operation of the flow regulator, the valve bonnet being withdrawable from the valve body together with the bonnet-mounted regulating means without dismounting the actuator means.

6. A valve is claimed in Claim 5 wherein the valve is arranged such that when the valve bonnet with bonnet-mounted regulating means is presented to the valve' body to be operatively secured thereto, the actuator means and the control member automatically undergo mutual operative engagement, and vice versa upon withdrawal of the valve bonnet from the valve body.

7. A valve as claimed in claim 6 wherein mutual operative engagement of the actuator means and the control member is achieved by means of a motion coupling means of which mutually cooperable parts are respectively mounted on the actuator means and the control member.

8. A valve as claimed in claim 7 wherein the mutually cooperable parts of the motion coupling means are mutually engagable and disengagable solely by means of the relative movement between the valve bonnet (with bonnet-mounted regulating means) and the valve body during presentation and withdrawal of the bonnet respectively.

9. A valve as claimed in any of claims 5 to 8 wherein the actuator means is formed and disposed so as to surround the control member in use of the valve, the actuator means comprising a central aperture at least sufficiently large to permit the valve bonnet with bonnet-mounted regulating means to be withdrawn from the valve body through the central aperture.

10. A valve as claimed in any of claims 5 to 9 wherein selective actuation of the fluid flow regulator is achievable by rotation of the control member about an axis, and the actuator means is a rotary actuator disposed to produce rotary movement about a substantially coaxial axis.

11. A valve as claimed in any of claims 5 to 10 wherein the valve is fitted with projecting guide posts for the docking of maintenance equipment.

12. A valve as claimed in claim 11 wherein the guide posts are anchored in the valve body and the guide post anchorages also serve to clamp the rotary actuator to the valve body.

13. A remotely operated valve substantially as hereinbefore described with reference to and as shown in the accompanying drawing.