WO2016078689A1

WO2016078689A1 - Valve operator assembly with anti-rotation means

Info

Publication number: WO2016078689A1
Application number: PCT/EP2014/074763
Authority: WO
Inventors: Jérôme DUBUS; Christian Boch
Original assignee: Aktiebolaget Skf
Priority date: 2014-11-17
Filing date: 2014-11-17
Publication date: 2016-05-26

Abstract

A valve operator assembly is provided for a valve and comprises a housing (18), an input member (20) rotatably mounted with respect to said housing, and a transmission mechanism (22) comprising a translating element (24) and provided with a thread, and a rotating element (28) provided with a thread. The assembly further comprises first anti-rotation and axial guide means (56) provided on the translating element (24) of the transmission mechanism and second anti-rotation and axial guide means (58) provided on the housing (18). The first anti-rotation and axial guide means comprise at least one protruding element (60) secured to the translating element. The second anti-rotation and axial guide means comprise at least one straight anti-rotation portion (59) extending axially and cooperating with said protruding element so as to guide axial movements and to prevent angular movement of the translating element (24) relative to the housing (18).

Description

Valve operator assembly with anti-rotation means

The present invention relates to the fields of valves and manually operable valves, for instance gate valves, control or regulation valves or chokes valves. More particularly, the invention relates to a valve operator assembly for a gate valve.

Valves are used in a variety o f industries to control the flow o f fluids. In particular, gate valves are used extensively in the oil and gas industry to control the flow o f produced fluids at various stages o f production. Most gate valves used in this industry comprise a valve body having a longitudinal flow bore and a transverse gate cavity that intersects the flow bore. A gate having a gate opening extending transversely therethrough is disposed in the gate cavity. A valve stem is provided for moving the gate between an open position, in which the gate opening is aligned with the flow bore, and a clo sed position, in which the gate opening is offset from the flow bore. The gate cavity o f the valve body is covered by a bonnet having an axial bore transverse to the flow through which passes the valve stem.

Such a gate valve is associated to a valve operator assembly for selectively driving the valve stem up and down in order to close and open the gate valve. The valve operator assembly generally comprises a transmission mechanism to convert the rotational motion o f a drive input into axial motion of the valve stem. To quickly open and close the gate valve with a minimum number of turns, the transmission mechanism may be a ball screw mechanism or a planetary roller screw mechanism in order to reduce the operating torque, for instance manual hand-wheel torque or powered with electric, hydraulic or pneumatic drive for surface valves or with remote operating vehicle (ROV) torque tool or electric or hydraulic actuation for subsea valves. For more details, it is possible for example to refer to the patent EP- B l - 1 419 334 (SKF) .

Generally, the translating element of the transmission mechanism is connected to the gate of the valve body by the valve stem, and the anti-rotation torque of said translating element is supported by a seat of the gate cavity onto which said gate is bearing . This induces a resistance for the translation movement of the gate, which increases the required operating torque on the transmission mechanism. Otherwise, since it is a fluid pressurized area, it may affect the sealing function o f the valve and then necessitate more often maintenance.

One aim o f the present invention is to overcome these drawbacks.

It is a particular object of the present invention to provide a valve operator assembly for valve, for instance gate valve, control or regulation valve or choke valve, wherein the required torque for manipulating said valve is limited.

In one embodiment, the valve operator assembly is provided for a valve comprising a valve body and a valve translating member axially moveable. The assembly comprises a housing adapted to be mounted on the valve, an input member rotatably mounted with respect to said housing, and a transmission mechanism comprising a translating element adapted to be connected to the valve translating member of the valve and provided with a thread, and a rotating element connected to the input member and provided with a thread. Said transmission mechanism is adapted to convert applied rotation o f the input member into axial translation of said translating element.

The assembly further comprises first anti-rotation and axial guide means provided on the translating element of the transmission mechanism and second anti-rotation and axial guide means provided on the housing. One o f said first and second anti-rotation and axial guide means comprises at least one protruding element secured to the translating element or to the housing. The other anti-rotation and axial guide means comprises at least one straight anti-rotation portion extending axially and cooperating with said protruding element so as to guide axial movements and to prevent angular movement of the translating element relative to the housing . In one embodiment, the anti-rotation portion comprises at least one guide surface extending parallel with the axis of the translating element and in contact with the protruding element. Preferably, the anti-rotation portion comprises facing guide surfaces extending parallel with each other.

The protruding element may protrude radially with respect to the translating element or with respect to the housing.

In one embodiment, the straight anti-rotation portion is formed by a groove within which engages the protruding element. The groove may be formed on the bore of the housing. Alternatively, the groove may be formed on the outer surface o f the translating element.

The straight anti-rotation portion may be attached to the housing or to the translating element.

The protruding element may comprise a pin or a key.

In one embo diment, said anti-rotation and axial guide means further comprises a rolling means mounted onto the protruding element, rotatable about an axis and provided with an outer surface rollable along the straight anti-rotation portion.

The transmission mechanism may comprise a screw provided with an outer thread and a nut surrounding and coaxial with said screw, said nut being provided with an inner thread. In this case, the screw forms the translating element and the nut forms the rotating element, or vice versa.

The invention also relates to a valve comprising a valve body, a valve translating member axially moveable and a valve operator assembly as previously defined.

The present invention and its advantages will be better understood by studying the detailed description o f specific embodiments given by way o f non-limiting examp les and illustrated by the appended drawings on which:

Figure 1 is a cross-section o f a valve operator assembly for gate valve according to a first examp le o f the invention,

Figures 2 and 3 are detail views o f Figure 1 ,

Figure 4 is a section on IV-IV of Figure 1 , and Figure 5 is a cross-section o f a valve operator assembly according to a second example of the invention.

A valve operator assembly 10 as shown on Figure 1 is adapted for a gate valve 12 provided with a bonnet 14, a valve body (not shown) covered by said bonnet and a moveable valve stem 16 with an axis 16a. Conventionally, the valve bo dy has a flow bore and a transverse gate cavity that intersects the flow bore. The gate valve also comprises a gate having a gate opening extending transverse ly therethrough is disposed in the gate cavity. For more detail on such a gate valve, it could be referred to EP-B l - 1 419 334 (SKF) .

The valve operator assembly 10 comprises a tubular housing 1 8 mounted on the bonnet 14 of the gate valve, an input member 20 rotatably mounted with respect to said housing, and an inverted roller screw mechanism 22 interposed between said input member and the valve stem 16 of said valve to convert a rotational motion o f the input member 20 into axial motion of the valve stem. The inverted roller screw mechanism 22 is mounted into a bore 1 8a of the housing and is connected to the input member 20. One axial end of the housing 1 8 is secured to the bonnet 14 by threads or bolts. In the illustrated example, the bore 1 8a has a stepped form. Alternatively, the bore 1 8a may have different shape.

As shown more clearly on Figure 2, the mechanism 22 comprises a screw 24, with an axis 24a coaxial with the axis of the valve stem, provided with an outer thread 26, a nut 28 mounted coaxially about the screw 24 and provided with an inner thread 30, the internal diameter of which is greater than the external diameter of the outer thread 26, and a plurality o f longitudinal rollers 32 arranged radially between the screw 24 and the nut 28. The screw 24 extends longitudinally through a cylindrical bore of the nut 28 on which the inner thread 30 is formed. The lead o f the outer thread 26 of the screw is constant. The nut 28 has a tubular form and is elongated to accommo date the full extent of screw travel.

The ro llers 32 are identical to each other and are distributed regularly around the screw 24. Each roller 32 extends along an axis 32a which is coaxial with the axis 24a o f the screw and comprises an outer thread 34 engaging the thread 26 o f the screw and the thread 30 of the nut. Each roller 32 also comprises, at each axial end, outer gear teeth 36, 38 extending axially outwards the outer thread 34 and which are themselves extended axially by a cylindrical stud 40, 42 extending outwards. Each gear teeth 36, 38 are axially located between the associated stud 40, 42 and the outer thread 34. The outer thread 34 o f each ro ller is axially lo cated between the two gears 36, 38.

The ro ller screw mechanism 22 also comprises two annular gear wheels 44, 46 provided on the outer surface of the screw 24 and each comprising outer gear teeth meshing the gear teeth 36, 38 respectively o f the ro llers 32 for the synchronization thereof. Each gear wheel 44, 46 is axially located near to an end of the outer thread 26 of the screw. Said outer thread 26 is axially located between the two gear wheels 44, 46. In the disclo sed embodiment, the gear wheels 44, 46 are formed directly on the outer surface of the screw 24. Alternatively, the gear wheels may be separate parts which are fixed onto the screw 24.

The mechanism 22 further comprises two annular guides or spacer rings 48 , 50 disposed on the outer surface of the screw 24. Said spacer rings 48 , 50 are radially disposed between the screw 24 and the inner thread 30 of the nut without contact with said thread. Each spacer ring 48 , 50 is mounted on the outer surface of the screw 24 axially next to the associated gear wheel 44, 46. Each spacer ring 48 , 50 is axially offset towards the outside of the nut 28 with regard to the associated gear wheel 44, 46. Each spacer ring 48 , 50 comprises a plurality o f cylindrical through-recesses (not referenced) which are distributed regularly in the circumferential direction and inside which the studs 40, 42 o f the rollers are housed. The spacer rings 48 , 50 enable the rollers 32 to be carried and the regular circumferential spacing thereo f to be kept. The mechanism 22 further comprises elastic retainer rings 52, 54 each mounted in a groove (not referenced) formed on the outer surface of the screw 24 in order to axially ho ld the corresponding spacer ring 48 , 50. Referring once again to Figure 1 , as will be described later, the valve operator assembly 10 further comprises first anti-rotation and axial guide means 56 connected to the screw 24 and associated second anti-rotation and axial guide means 58 provided on the housing 1 8 in order to prevent angular movements of said screw relative to said housing.

The valve operator assembly 1 0 also comprises rolling bearings 66 to 68 to guide the rotation of the nut 28 of the inverted roller screw mechanism. The rolling bearings 66 to 68 are radially mounted between the outer surface of the nut 28 and the stepped bore 1 8a of the housing. The rolling bearings 66 to 68 are mounted radially in contact with the outer surface of the nut 28 and a large diameter portion of the stepped bore 1 8a of the housing. In the disclo sed examp le, the rolling bearings 66 to 68 are angular contact thrust ball bearings and are disposed axially in contact one to another. A retaining ring 69 is secured on the outer surface of the nut 28 and axially bears against the rolling bearing 66. Axially on the opposite side, the rolling bearing 68 is axially mounted against a flange (not referenced) o f the nut 28 extending radially outwards the outer surface of said nut. The flange is axially located at an axial end of the nut.

The input member 20 comprises an adapter sleeve 74 mounted on the nut 28 and an operable hand-wheel 76 secured to said sleeve . The hand-wheel 76 forms a rotational drive input. The sleeve 74 comprises an annular axial portion 74a secured to the flange of the nut by any appropriate means, for example by threads, a radial portion 74b extending radially inwards said axial portion 74a, and a pin 74c proj ecting axially outwards from said radial portion 74b and onto which is secured the hand-wheel 76. The axial portion 74a bears axially against the end of the nut 28. Sealing means (not referenced) are provided between the axial portion 74a of the sleeve and the bore of the housing 1 8.

Referring once again to Figure 1 , axially on the side opposite to the input member 20, a recess 24c is formed on a frontal radial surface o f the screw 12 and into which is mounted an end o f the valve stem 16 o f the gate valve. The valve stem 16 is connected to the screw 24 by any appropriate means, for example by threads and/or a pin.

As shown more clearly on Figures 3 and 4, the first anti- rotation and axial guide means 56 are secured to the screw 24. These means 56 radially protrude outwards with respect to the outer surface of the screw 24. The anti-rotation and axial guide means 56 are lo cated at a fixed position on the screw 24. The second anti-rotation and axial guide means 58 comprises a groove 59 provided on the housing 1 8. As will be described later, the first anti-rotation and axial guide means 56 are rollable along the groove 59 o f the second anti-rotation and axial guide means 58.

The anti-rotation and axial guide means 56 comprise a pin 60 connected with the screw 24 and a roller 62 rotatably coupled with the pin. The roller 62 may be maintained on the pin 60 by a screw (not shown) . In the illustrated example, the anti-rotation and axial guide means 56 further comprise a sleeve 64 radially surrounding the part of the pin 60 which protrudes outwards. The sleeve 64 radially bears against the outer surface of the screw 24.

The pin 60 is connected to the screw 24. The pin 60 radially protrudes outwards with respect to the outer surface of the screw 24.

The pin 60 comprises an inner mounting portion (not referenced) mounted into a hole 24b o f the screw and an outer mounting portion (not referenced) onto which is rotatably mounted the roller 62. In the illustrated example, the inner mounting portion of the pin 60 comprises an external thread cooperating with an internal thread of the ho le 24b to secure the anti-rotation and axial guide means 56 onto the screw 24. Alternatively, the pin 50 may be secured to the nut 16 by any other appropriate means, for instance by press-fitting, gluing, or welding, etc. The ho le 24b extends radially from the outer surface o f the screw.

The ro ller 62 is radially spaced apart from the screw 24. The roller 62 is mounted into the groove 59 provided on the housing 1 8 and is rollable along said groove. The roller 62 engages within the groove 59. The roller 62 is rotatable about an axis 62a located at a fixed position on the screw 24. The axis 62a is perpendicular to the axis 24a of the screw. With regard to the axis 24a, the axis 62a extends radially. The roller 62 comprises an outer rolling surface 62b . In the illustrated example, the rolling surface 62b has a cylindrical form. In another embodiment, the rolling surface may have a profile with curvatures or be a combination o f several surfaces.

The groove 59 is formed on the bore 1 8a of the housing. The groove 59 is formed radially towards the outside from the bore 1 8a. The groove 59 is made into the thickness o f the housing 1 8. The groove 59 is formed on a limited length of the bore 1 8a. The groove 59 is axially lo cated on the housing 1 8 between the nut 28 of the screw mechanism and the end o f the screw 24 connected to the valve stem 16 (Figure 1 ) .

The groove 59 is delimited by two guide surfaces 59a, 59b facing each other. The guide surfaces 59a, 59b extend parallel to each other. The ro ller 62 is disposed between the guide surfaces 59a, 59b . The guide surfaces 59a, 59b form guideways for the roller 62. The guide surfaces 59a, 59b extend axially on the housing 1 8 , i.e. paralle l with the axis 24a of the screw. The roller 62 rolls along the guide surfaces 59a, 59b o f the groove and comes into contact with said surfaces . The spacing distance between the surfaces 59a, 59b is slightly greater than the diameter of the roller 62 at least at the contact position. The groove 59 forms a straight anti-rotation portion extending parallel to the axis 24a of the screw. The straight groove 59 extends purely axially with regard to the axis 24a.

When an operator applies a torque on the hand-wheel 76, this torque is transmitted to the nut 28 of the inverted roller screw mechanism. With the rotation of the nut 28 , the rollers 32 rotate on themselves about the screw 24 and move axially and additionally rotate in the nut 28. The rollers 32 are rotationally guided by outer gear wheels 44, 46 provided on the screw and meshing with the gear teeth of the rollers. Both the rollers 32 and the screw 12 are axially or longitudinally moveable into the nut 28. Accordingly, the rotational motion o f a hand-wheel 76 is converted into a displacement of the screw 24.

With the anti-rotation and axial guide means 56 secured to the screw 24 and engaged within the straight groove 59 of the housing as shown on Figure 1 , the rotation of the nut 28 is converted into a linear translation of the screw 24. Said linear guidance of the screw 24 is done along its axis 24a. The screw 24 only has an axial movement relative to the nut 28 and the housing 1 8. An angular movement of the screw 24 is prevented by the cooperation of the first anti-rotation and axial guide means 56 with the second anti-rotation and axial guide means 58. The roller 62 of the anti-rotation and axial guide means rolls along the guide surfaces 59a, 59b of the groove 59. The valve stem 1 6 of the valve gate is axially moved together with the screw 24. The straight groove 59 forms a guiding path for the anti-rotation and axial guide means 56 and enables to prevent, during rotation of the nut 28 , a rotation movement o f the screw 24 with regard to said nut and the housing 1 8.

Besides, integrating the anti-rotation and axial guide means 56 , 58 into the valve operator assembly 10 decreases friction at the translating gate of the associated valve and minimizes the required operating torque. Since the anti-rotation and axial guide means are not provided into the valve 12 but rather integrated within the associated valve operator assembly 10, the sealing of the valve may be improved in the fluid pressurized area.

In this embodiment, the first anti-rotation and axial guide means 56 are connected to the screw 24 and the second anti-rotation and axial guide means 58 are provided on the housing 1 8. Alternatively, it is also possible to have an inverted arrangement with the first anti-rotation and axial guide means 56 connected to housing 1 8 and the second anti-rotation and axial guide means 58 provided on the screw 24 as illustrated on Figure 5 , in which identical parts are given identical references .

In this second examp le, the first anti-rotation and axial guide means 56 are secured to the housing 1 8 and radially protrude inwards with respect to the bore 1 8a of the housing. The anti-rotation and axial guide means 56 are lo cated at a fixed position on the housing 1 8. The pin 60 o f said means is mounted into a hole (not referenced) provided in the thickness of the housing 1 8. The pin 60 radially protrudes inwards with respect to the bore 1 8a of the housing. The ro ller 62 mounted on the pin 60 is radially spaced apart from the housing 1 8.

The roller 62 is mounted into the groove 59 provided on the screw 24 and is ro llable along said groove. The roller 62 engages within the groove 59. The groove 59 is formed on the outer surface o f the screw 24. The groove 59 is formed radially towards the inside from said outer surface. The groove 59 is made into the thickness o f the screw 24. The groove 59 is formed on a limited length of the screw 24. The groove 59 is axially located between the outer thread o f the screw 24 and its end connected to the valve stem 16. The groove 59 is similar to the groove of the first example . The groove 59 is delimited by two guide surfaces parallel and facing each other. The guide surfaces extend axially on the screw 24, i. e. parallel with the axis 24a. The ro ller 62 ro lls along the guide surfaces of the groove and comes into contact with said surfaces . The groove 59 forms a straight anti- rotation portion extending parallel to the axis 24a of the screw. The straight groove 59 extends purely axially with regard to the axis 24a.

The invention has been illustrated on the basis o f a valve operator assembly for gate valve comprising an inverted roller screw mechanism. The invention can also be applied to a valve operator assembly having other type o f roller screw mechanism such as standard planetary roller screw mechanism. The invention can also be applied to a valve operator assembly having a standard or an inverted ball screw mechanism. Otherwise, the invention can also be applied to a valve operator assembly having other type o f transmission mechanism adapted to convert a rotation into a linear movement, for instance a direct threaded connection. In this case, the outer thread of the screw engages directly the inner thread of the nut without interposition o f rolling elements. However, such transmission mechanism requires large actuation forces . Although the invention has been illustrated on the basis of a valve operator comprising a screw connected to the valve stem o f the gate and a nut connected to the input member, it should be understood that the invention can be applied with a screw connected to the input member and a nut connected to the valve stem. In this case, the nut acts as the translating element and the screw acts as the rotating element.

In the described examples, the first anti-rotation and axial guide means comprise the protruding element are connected or coupled directly to the translating element of the transmission mechanism or to the housing. Alternatively, it could be possible to foresee an indirect connection between these means and the translating element, or the housing, in which one or more other components are interposed therebetween. In the disclo sed examples, a rotatable roller is provided on the protruding element in order to limit friction with the associated groove. Alternatively, other component may be provided on the protruding element to engage within the groove, for example a ro lling bearing or a plain bearing. In these cases, the protruding element cooperates indirectly with the associated groove. Alternatively, the protruding element may only comprise a pin or key. In these cases, the protruding element cooperates directly with the associated groove. In another variant, it could also be possible to use several protruding elements connected to the translating element o f the transmission mechanism or to the housing. In this case, it is necessary to provide for each protruding element one associated groove.

In the disclo sed examples, the straight anti-rotation portion o f the second anti-rotation and axial guide means is formed by a groove provided directly on the housing or on the translating element of the transmission mechanism. Alternatively, the groove may be delimited by two separate plates attached directly to the housing or to the translating element, by any other appropriate means.

In another variant, it could also be possible to foresee another type of straight anti-rotation portion to cooperate with the protruding element of the other anti-rotation and axial guide means, for example two separate straight wires extending axially may be provided instead of a groove. In this case, the protruding element engages between the wires .

Although the invention has been illustrated on the basis of a valve operator assembly for gate valve, it should be understood that the invention can also be used with other types of valves, for instance control or regulation valves or choke valves . The valve operator assembly may be used for instance with a surface gate or a subsea valve gate which may be actuated by a remote operating vehicle (ROV) torque tool or an actuator.

Claims

1 . Valve operator assembly for valve comprising a valve body and a valve translating member axially moveable, the assembly comprising a housing ( 1 8) adapted to be mounted on the valve, an input member (20) rotatably mounted with respect to said housing, and a transmission mechanism (22) comprising a translating element (24) adapted to be connected to the valve translating member of the valve and provided with a thread, and a rotating element (28) connected to the input member and provided with a thread, said transmission mechanism being adapted to convert applied rotation of the input member into axial translation of said translating element, characterized in that the assembly further comprises first anti-rotation and axial guide means (56 ; 58) provided on the translating element (24) of the transmission mechanism and second anti-rotation and axial guide means (58 ; 56) provided on the housing ( 1 8), one of said first and second anti-rotation and axial guide means comprising at least one protruding element (60) secured to the translating element or to the housing, the other anti-rotation and axial guide means comprising at least one straight anti-rotation portion (59) extending axially and cooperating with said protruding element so as to guide axial movements and to prevent angular movement of the translating element (24) relative to the housing ( 1 8) .

2. Valve operator assembly according to claim 1 , wherein the anti-rotation portion (59) comprises at least one guide surface extending parallel with the axis (24) o f the translating element (24) and in contact with the protruding element (60).

3. Valve operator assembly according to claim 2, wherein the anti-rotation portion (59) comprises facing guide surfaces (59a, 59b) extending parallel with each other.

4. Valve operator assembly according to any o f the preceding claims, wherein the protruding element (60) protrudes radially with respect to the translating element (24) or with respect to the housing ( 1 8) .

5. Valve operator assembly according to any of the preceding claims, wherein the straight anti-rotation portion (59) is formed by a groove within which engages the protruding element (60) .

6. Valve operator assembly according to claim 5 , wherein the groove is formed on the bore of the housing ( 1 8) .

7. Valve operator assembly according to claim 5 , wherein the groove is formed on the outer surface of the translating element (24) .

8. Valve operator assembly according to any of the preceding claims 1 to 4, wherein the straight anti-rotation portion (59) is attached to the housing ( 1 8) or to the translating element (24) .

9. Valve operator assembly according to any of the preceding claims, wherein the protruding element (60) comprises a pin.

10. Valve operator assembly according to any of the preceding claims, wherein said anti-rotation and axial guide means further comprises a rolling means (62) mounted onto the protruding element (60), rotatable about an axis (62a) and provided with an outer surface (62b) rollable along the straight anti-rotation portion (70) .

1 1 . Valve operator assembly according to any o f the preceding claims, wherein the transmission mechanism (22) comprises a screw (24) provided with an outer thread and a nut (28) surrounding and coaxial with said screw, said nut being provided with an inner thread.

12. Valve operator assembly according to claim 1 1 , wherein the screw (24) forms the translating element and the nut (28) forms the rotating element, or vice versa.

13. Valve comprising a valve body, a valve translating member

( 16) axially moveable and a valve operator assembly ( 10) according to any o f the preceding claims .