AU2007314155B2

AU2007314155B2 - Valve operation

Info

Publication number: AU2007314155B2
Application number: AU2007314155A
Authority: AU
Inventors: Ramon Horton; Wayne Leonard; Robert Mckenna; Frank Wheel
Original assignee: Alcoa of Australia Ltd
Current assignee: Alcoa of Australia Ltd
Priority date: 2006-10-31
Filing date: 2007-10-31
Publication date: 2013-06-20
Anticipated expiration: 2027-10-31
Also published as: WO2008052268A2; WO2008052268A3; AU2007314155A1

Abstract

An operating mechanism (40) for a valve (11) having a valve body (13) defining a valve seat (19) and a valve member (21) moveable into and out of engagement with the valve seat (19). The valve member (21) comprises a valve disc (25), a valve stem (23), and a bush (29) through which the valve stem (23) extends in threaded engagement therewith whereby relative rotation between the bush (29) and the valve stem (23) causes axial displacement of the valve stem (23) relative to the bush (29). The operating mechanism (40) comprises two operating drive sockets (104, 106) in opposed relation, each of which is drivingly connected to the bush (29). The operating mechanism (40) also comprises two unlocking drive sockets (118, 120) in opposed relation, each of which is drivingly connected to the bush (29). The drive ratio between the operating drive sockets (104, 106) and the bush (29), and the drive ratio between the unlocking drive sockets (118, 120) and the bush (29) are different from each other such that a larger torque is delivered to the bush (29) from operation of either one of the unlocking drive sockets (118, 120) in comparison to the torque delivered to the bush (29) from operation of the either one of the operating drive sockets (104, 106) for the same torque input. With this arrangement, either one of the unlocking drive sockets (118, 120) can be used for unlocking the valve; that is, to move the valve member (21) into a "just open" or throttled position in which the valve disc (25) is out of sealing engagement with the valve seat (19) without rotation of the valve stem (23). Further, either one of the operating drive sockets (104, 106) can be used for opening and closing the valve (11), as well as valve locking. Because there are two operating drive sockets (104, 106) in opposed relation, and also two unlocking drive sockets (118, 120) also in opposed relation, an operator can access the operating mechanism (40) from either side thereof according to what is more convenient.

Description

WO 2008/052268 PCT/AU2007/001665 1 "Valve Operation" FiellJ of the Invention This invention relates to operation of valves. More particularly, the invention is concerned with an operating mechanism for a valve and also an apparatus for 5 operating a valve, as well as a valve incorporating such an operating mechanism. Background Art There are certain types of valves which not only have a mechanism for openng and blosing the valve but also have a mechanism for initiating movement of t6e valve out of the closed condition (known as unlocking the valve). One such valve 10 is a drain valve commonly used in alumina processing plants. Sucn valves typically comprises a valve body having an inlet and an outlet between which fluid can flow. The valve body incorporates a valve seat adjacent the outlet, as well as a valve member moveable into and out of sealihg engagement with the valve seat for closing and opening the valve. The valve 15 niember comprises a valve disc supported on one end of a valve stem which can be traversed in order to move the valve disc into and out of sealing engagemcdint with the valve seat. Typically, the valve stem is rotatably supported in a yoke bush with which the valve stem is threadingly engaged. The threaded engagement is provided by tIhe 20 valve stem being externally threaded and the yoke bush being internally threaded, whereby rotation of the valve stem relative to the yoke' bush causes axial movement of the valve stem in one direction or the other, according to th e direction of rotation of the valve stem. The valve stem is rotated by turning an operating handle fitted onto the outer end of the valve stem. The yoke bush is 25 rotatably supported in the yoke and can be rotated by a yoke bush handle. Turning the yoke bush handle causes the yoke bush to be rotated about the valte stem with which it is in threaded engagement. This causes the valve stem to move axially with respect to the yoke bush, and so can be used to move the vai e WO 2008/052268 PCT/AU2007/001665 2 disc out of sealing engagement with the valve seat (which is known as crackingg" open the valve). Once the valve has been "cracked" open, the operating handle can Tbe used to rotate the valve stem with respect to the yoke bush to move the valve disc away from the valve seat and so continue opening of the valve. Ifhe 5 valve can be closed simply by rotating the operating handle in the opposite direction to move the valve disc into sealing engagement with the valve seat, The yoke bush handle may be used to lock the valve in the closed condition, but this is generally unnecessary with certain valves including drain valves. The Itorque required to rotate the yoke bush in order to unlock the valve to move 10 the alve disc Qut of sealing engagement with the valve seat can be significantly greater than the torque required to close the valve to effect sealing engageme t, Indeed, the torque required for valve unlocking can be as much as two to there times greater than the torque required for valve looking. There are several factors which can contribute to the different torque requirements, one being addition al 15 compression forces to which the valve member might be subjected once the valve has been closed (owing to thermal contractions within the valve), It is because of the greater force required for unlocking of the valve that it is necessary to use the yoke' bush handle. Forces much greater than those achievable by an operator without meohani al 20 inter ention are required to operate the valve handles, particularly the yoke bush handle during the valve unlocking stage. Accordingly, it is common to use impact device (such as a sledge hammer) to strike the handles to cause them to turn. The reed to turn the yoke bush.handle and also the operating handle manually by 25 striking them with means such as a sledge hammer can be exhausting, and also dangerous, for an operator. An operator can, for example, develop injuries through having to swing a heavy sledge hammer for prolonged periods. Further, injuries can also be sustained in cases where an operator does not strike t, e targeted handle correctly, with the result that the sledge hammer.deflects from t e 30 handle, or misses the handle altogether, and hits the operator or other personn I, or equipment, in the vicinity.

WO 2008/052268 PCT/AU2007/001665 3 There is a need for a mechanism which would allow a valve to be operated in a manner which is less manually intensive and does not require that the yoke bdsh handle and the operating handle to be struck manually with a sledge hammer. It is against this background, and the problems and difficulties associated 5 therewith, that the present invention has been developed. Disclosure of the Invention According to a first aspect of the invention there is provided an operating mechanism for a valve having a valve body defining a valve seat and a valve member moveable into and out of engagement with the valve seat, the valve 10 member comprising a valve disc and a valve stem, and a bush through which the valv6 stem extends in threaded engagement therewith whereby relative rotation between the bush and the valve stem causes axial displacement of the valve stem relative to the bush, the operating mechanism comprising two operating drive inpufs each of which is drivingly connected to the bush, either one of the tio 15 operating drive inputs being selectively operable for delivery of torque to the bush to case rotation thereof about the valve stem. Preferably the two operating drive inputs are rotatable about a common axis ahd are disposed on opposed sides of the operating mechanism. Preferably, the operating mechanism further comprises two unlocking drive inputs 20 each, of which is drivingly connected to the bush, the drive ratio between t 6 e operating drive inputs and the bush and the drive ratio between the unlockiig drive inputs and the bush being different from each other such that a larger torq le is delivered to the bush from operation of either one of the unlocking drive inputs in comparison to the torque delivered to the bush from the either one of the 25 operating drive inputs for the same torque input. Preferably, the operating drive inputs and the unlocking drive inputs are each drivin iply connected to the bush through a gear train, the gear ratio between t'i e operating drive inputs and the bush and the gear ratio between the unlockirg WO 2008/052268 PCT/AU2007/001665 4 drive inputs and the bush being different from each other to provide the different drive ratios. Preferably, the gear train comprises a bush drive gear adapted for connection to the bush whereby rotation of the bush drive gear imparts rotary motion to The 5 bush. Preferably, the gear train is supported on a base plate. Preferably, the operating mechanism further comprises a hub adapted to be mounted on the bush for rotation therewith, the hub being configured to define the bush drive gear. With this arrangement, the valve stem extends through the hub. 10 Preferably, the gear train comprises the bush drive gear in meshing engagement with an operating gear to which the two operating drive inputs are drivihg connected. Pref rably, the operating gear is connected to an intermediate gear for rotation therdwith, the intermediate gear being in meshing engagement with a pinion to 15 which the unlocking drive inputs are drivingly connected. It is 'he presence of the pinion and the intermediate gear that establishes the different drive ratios between the respective drive inputs and the bush such tha a larger torque is delivered to the bush from the unlocking drive inputs in com aison to the torque delivered to the bush from the operating drive inputs for 20 the same torque input. Preferably, each unlocking drive input is drivingly connected to the pinion throu h a respective ratchet adapted to transmit rotational torque to the pinion uppn rotation of the unlocking drive input in one direction and adapted to free-whdel upon' rotation of the unlocking drive input in the other direction so as not Io 25 transmit any rotational torque to the pinion.

WO 2008/052268 PCT/AU2007/001665 5 Preferably, the hub is fixed against rotation with respect to the bush by a key, thereby being rotatable with the bush. Preferably, the hub has a peripheral flange which is configured as a spur g ar which provides the bush gear. 5 The operating gear and the intermediate gear may each be defined by a first rotatable element The first rotatable element may also define a stub shaft which is rotatably supported within a first support- sleeve on the base plate. Preferably, the first rotatable element has an axis of rotation and two oppo ed axial ends one of which is configured to provide a first one of the two operating 10 drive inputs and the other of which is configured to provide a second one of the two operating drive inputs. The pinion may be defined by a second rotatable element, The second rotatable element may be rotatably supported within a second support sleeve on the base plate. Preferably, the second rotatable element has an axis of rotation and two opposPd 15 axial, ends one of which is configured to provide a first one of the two unlocking drive inputs and the other of which is configured to provide a second one of tke two unlocking drive inputs. Preferably, the operating mechanism further comprises a cover about the gear train 20 Preferably, the operating mechanism further comprises means for restraining the vaivd stem against rotation while allowing axial movement thereof in response Ito rotation of the bush. Preferably, the means for restraining the valve stem against rotation while allowing axial movement thereto in response to rotation of the bush comprises a 26 first element and a second element, the first element being fixedly supported on the threaded shank of the valve stem, and the second element cooperating with the first element to allow relative displacement of the first element in a direction WO 2008/052268 PCT/AU2007/001665 6 corresponding to the axis of the valve stem and to also block rotation of the first element relative to the second element about the axis of the valve stem, Preferably, the second element comprises a sleeve and the first element comprises a block accommodated in the sleeve for sliding movement therealong. 5 The sleeve may be of rectangular cross-section and the block is of a matching cross section to allow the sliding movement therealong' while being constrained against rotation therein, Typically, the sleeve is rigidly mounted on part of the'operating mechanism sdch as o6 the casing. 10 Prefbrably, the operating drives inputs and the unlocking drive inputs each comprises a drive socket. Preferably, the operating drive inputs and the unlocking drive inputs are each adapted to receive a driving tool. In this way, the driving tool can be applied ito any bne of the drive inputs at the time that rotational torque is required to be 15 applied thereto. Whete the operating drive inputs and the unlocking drive inputs each comprise a drive, socket, the driving tool preferably has a drive spigot for mating engagement with the sockets. While the driving tool can take any Appropriate form, it is particularly convenient 20 that it be a powered driving tool such as an air-operated torque gun. Reaction torque is generated during operation of a powered driving tool such a torque gun and so it is advantageous that there be a mechanism for transferring the reaction torque away from the operator of the powered driving tool rather than the operator having to resist the reaction torque. 25 For this purpose the operating mechanism may further comprise a fixed coupliig element associated with each of the operating drive inputs and the unlocking drive WO 2008/052268 PCT/AU2007/001665 7 L inputs, the coupling element being adapted to cooperate with a correspond ing coupling element on the powered driving tool, cooperation between the two coupling elements being adapted to allow displacement therebetween in the direction corresponding to the axis of rotation of the driving tool while constraining 5 the tyvo coupling elements against relative rotation about the axis of rotation. With' this arrangement, reaction torque arising from operation of the powered driving tool is transferred through the coupling element on the tool to the respective fixed coupling element. In this way, an operator holding the powered driving tool merely has to guide the tool during its operation and does not have to 10 counteract any reaction torque. The fixed coupling element may comprise a sleeve and the second couplihg element may comprise a block which is mounted on the body of the driving to and which is adapted to be received in the sleeve for sliding movement therealong. 15 The sleeve may be of rectangular cross-section and the block may be ofj a matching cross-section to allow the sliding movement therealong while being constrained against rotation therein. Typidally, the sleeve is rigidly mounted on part of the operating mechanism, suph as ori the casing. 20 Acco ing to a second aspect of the invention there is provided a apparatus for operating a valve having a valve body defining a valve seat and a valve mem er moveable into and out of engagement with the valve seat, the valve member comprising a valve disc and a valve stem, and a bush through which the vaite stem extends in threaded engagement therewith whereby relative rotation 25 between the bush and the valve stem causes axial displacement of the valve steIF relative to the bush, the apparatus comprising an operating mechanism accordip g to the first aspect of the invention and further comprising a powered driving tdol for s lective engagement with the drive inputs for delivery of rotational torqi e thereto, the operating mechanism further comprising a fixed coupling element WO 2008/052268 PCT/AU2007/001665 8 associated with each drive input, the coupling element being adapted! to cooperate with a corresponding coupling element on the powered driving tool, cooperation between the two coupling elements being adapted to allow displacement therebetween in the direction corresponding to the axis of rotation of 5 the driving tool while constraining the two coupling elements against relative rotation about the axis of rotation. According to a third aspect of the invention there is provided a valve comprising a valve body defining a valve seat and a valve member moveable into and Outl of engagement with the valve seat, the valve member comprising a valve disc ani a 10 valve stem, a bush through which the valve stem extends in threaded engagement therewith whereby relative rotation between the bush and the valve stem causes axial displacement of the valve stem relative to the bush, and two operating drive inputs each of which Is drivingly connected to the bush, either one of thl two operating drive inputs being selectively operable for delivery of torque 15 to the bush to cause rotation thereof about the valve stem. According to a fourth aspect of the invention there is provided a valve comprising a valve body defining a valve seat and a valve member moveable into and out of engagement with the valve seat, the valve member comprising a valve disc and a valve stem, a bush through which the valve stem extends in threaded 20 engagement therewith whereby relative rotation between the bush and the valve stem' causes axial displacement of the valve stem relative to the bush, two operating drive inputs each of which is drivingly connected to the bush, either oPe of the two operating drive inputs being selectively operable for delivery of torq ie to the bush to cause rotation thereof about the valve stem, and two unlockihig 25 drive! inputs each of which is drivingly connected to the bush, the drive ratio between the operating drive inputs and the bush and the drive ratio between tihe unlocking drive inputs and the bush being different from each other such that a larger torque is delivered to the bush from operation of either one of the unlockirig drive inputs in comparison to the torque delivered to the bush from the either one 30 of the operating drive inputs for the same torque input.

WO 2008/052268 PCT/AU2007/001665 9 Brief Description of the Drawings The invention will be better understood by reference to the following descriptions of one specific embodiment as shown in the accompanying dmwings in which: Figure 1 is a schematic sectional side view of a conventional drain val ie 5 intended to be modified by apparatus according to the embodiment; Figure 2 is a sectional view of apparatus according to the embodiment fitted on to the conventional drain valve; Figures 3 to 6 are views similar to Figure 2 except that in each case' a powered driving tool is shown connected to the apparatus; 10 Figure 7 is a schematic elevational view of the apparatus fitted onto the drain valve; Figure 8 is an elevational view of the base plate; Figure 9 is a sectional view of the base plate; Figure 10 is a further sectional view of the base plate; 15 Figure 11 is an elevational view of the casing; Figure 12 is a sectional view of the casing; Figure 13 is an elevational view of the hub adapted to be fitted to the yole bush of the drain valve; Figure 14 is a sectional view of the hub; 20 Figure 15 is a sectional view of the first rotatable element; Figure 16 is an end view of the first rotatable element; WO 2008/052268 PCT/AU2007/001665 10 Figure 17 is a perspective view of the nut forming part of the restraining means for the valve stem; Figure 18 is a sectional view of the nut; Figure 19 is a perspective view of a block section forming part of the 5 restraining means for the valve stem; Figure 20 is an elevational view of the driving tool; Figure 21 is an elevational view of a coupling element attached to the driving tool; and Figure 22 is a side elevational view of the coupling element. 10 Best Mode(s) for Carrying Out the Invention The embodiment is directed to apparatus 10 for modifying a conventional long stem. drain valve 11 to convert it into a valve having provision for selectively performing the functions of valve opening, valve closing, valve unlocking and valve looking. In other words, the apparatus 10 can be retro-fitted to an existing 15 drain'valve 11. Before describing the apparatus 10 according to the embodiment, it is necessary to consider the conventional drain valve 11 which is to be modified by way of t he apparatus. The description of the conventional drain valve 11 will be made with reference to Figure 1. 20 The conventional drain valve 11 comprises a valve body 13 having an inlet 15, 6n outle 17 and a flow path 18 from the inlet 15 to the outlet 17. The body 13 incorporates an annular valve seat 19 adjacent the inlet 15. A valve member 21 is movable into and out of sealing engagement with the valve seat 19 for closing arnd opening the flow path 18 extending between the inlet 16 and the outlet 17. The 25 valve member 21 comprises a valve stem 23 and a valve disc 25 supported on one bnd of the valve stem, the valve disc 25 being adapted for sealirng WO 2008/052268 PCT/AU2007/001665 11 engagement with the valve seat 19. The valve stem 23 extends through an opening in the valve body 13 and is supported within a yoke 27 mounted on he valve body 13. The yoke 27 rotatably supports a yoke bush 29 through which the vaive stem 23 passes. The yoke bush 29 has a portion 30 incorporating an 5 intemal screw thread which engages with an external screw thread on the valve sten 23. The outer end of the valve stem 23 is fitted with an operating handle 33. Spedificaly, the outer end of the valve stem 23 has a drive spigot 24 with which the operating handle 33 drivingly engages. The operating handle 33 is retained in 10 position by retaining nut 34. A looking handle 35 is connected to the yoke bush 29. The locking handle 35 h s a central hub portion 36 which fits onto a portion 32 the yoke bush 29 and is fixed thereto by a key 37. A lock nut 38 engages the yoke bush 29 to retain the looking handle 35 in position. A lock washer 39 locks the nut 38 in position. 15 Modification of the conventional valve 11 to accommodate the apparatus 10 fist involves removal of the operating handle 33, the locking handle 35, the lock rut 38, the key 37, and the look washer 39. .The operating handle 33, the Iockihg hand je 35, and the look washer 39 are discarded, and the look nut 38 and the key 37 retained for subsequent use with installation of the apparatus 10. Once these 20.- parts of the conventional valve 11 have been removed to provide a stripped version of the valve, various parts of the apparatus 10 are then fitted, as will be described later. With the operating handle 33 removed, drive spigot 24 on the free end of the valve stem 23 is exposed. The apparatus 10 according to the embodiment comprises an operating 25 mechanism 40 which includes a gear assembly 41 and a mounting means 3 incorporating two mounting plates 45, 47 The operating mechanism 40 has provi ion for restraining the valve stem 23 against rotation while allowing ax ai movement, as will be explained in more detail later.

WO 2008/052268 PCT/AU2007/001665 12 The gear assembly 41, which is best shown in Figure 2, includes a gear train en supported on a base plate 63, The gear train 61 includes a hub 65 adapted to be mounted onto the yoke bush 29, the latter having been retained on the valve stem 23 in the stripped valve 11. The hub 65 is fixed against rotation with respect to 5 the oke bush 29 by yoke key 37 (which was also retained from the origi al valvb). The hub 65 has a peripheral flange 69 which is configured as a spur gear 71. The yoke bush nut 35 (from the original valve) retains the hub 65 in position on the yoke bush 29. The yoke bush nut 35 is retained in position by look was her 77, 10 The gear trai 61 further comprises an operating gear 91 in meshing engagem nt with ithe spur gear 71. The operating gear 91 is configured as part of a first rotatable element 93, The first rotatable element 93 is also configured to provide an intermediate gear 95 and a shaft section 97 which is rotatably supported wit iin a support sleeve 99 attached to the opposed side of the base plate 63. A buJsh 15 101 bf appropriate low-friction material is provided between the shaft section 97 and the support sleeve 99. The first rotatable element 93 has an axis of rotation and two axial end sections 102, ;one of which is configured to define a first operating drive input 103 and the othet of which is configured to define a second operating drive input 105. The first 20 operating drive input 103 comprises an operating drive socket 104, and the second operating drive input 105 comprises an operating drive socket 106. In tIlis embodiment, the two operating drive sockets 104, 106 are each configured as a female square drive facility. The intermediate gear 95 is in meshing engagement with a pinion 111 which 25 forms part of a second rotatable element 113. In the arrangement shown, tie second rotatable element 113 is assembled from two parts adapted [o interconnect to provide a driving connection therebetween. The second rotatable element 113 has a shaft section 114 which is rotatably supported within a support sleeve 116 mounted on the base plate 63.

WO 2008/052268 PCT/AU2007/001665 13 The second rotatable element 113 has an axis of rotation and two axial ehd sections 115, one of which is configured as a first unlocking drive input 117 and the other of which is configured as a second unlocking drive input. 119. The fist unlocking drive input 117 comprises an unlocking drive socket 118, and the 5 second unlocking drive input 119 comprises an unlocking drive socket 120. In this embodiment, the two unlocking drive sockets 118, 120 are each configured a , a female 3/4" drive facility. Eacn unlocKing drive socket 118, 120 operates through a ratchet mechanism 121 which provides for torque transmission in a direction corresponding to valve 10 unlocking only. The ratchet mechanism 121 is arranged to transmit rotational torque to the second rotatable element 113 (and hence to the pinion 111) upon rotation in one direction (to unlock the valve) and to free-wheel upon rotation in the other direction so as not to transmit any rotational torque to the second rotatsble element 113. 15 The gear train 61 thus drivingly connects both the operating drive sockets 104, 106 and the unlocking drive sockets 118, 120 to the yoke bush 29. Either one of the two unlocking drive sockets 118, 120 can be used for unlocki g the Valve; that is, to move the valve member 21 into a "just open" or throttled position (in which the valve disc 25 is out of sealing 'engagement with the valye 20 seat 19) without rotation of the valve stem 23. Further, either one of the two operating drive sockets 104, 106 can be used for opening and closing the valve, as well as valve locking. The separate unlocking drive sockets 118, 120 are provided for unlocking the valve as greater torque is required for that operation. By way of explanation, the 25 torque.required to rotate the yoke bush 29 in order to unlock the valve from tie closed condition can be significantly greater than the torque required to open aid close the valve (including locking the valve in the closed condition to effect sealig engaemerrt). In order to accommodate the different torque requirements, ti e gear tatlo between the yoke bush 29 and the unlocking drive sockets 118,120 is WO 2008/052268 PCT/AU2007/001665 14 different from the gear ratio between the yoke bush 29 and the operating dive sockets104, 106. More particularly, the presence of the pinion 111 and intermediate gear 95 in which it is meshing engagement provide the additi nal torque requirements. The ratchet mechanisms 121 associated with the unlocking 5 drive sockets 118, 120 to ensure that they can only be used for unlocking e valve. Because the ratchet mechanisms 121 do not transmit rotational torque when the unlocking drive sockets 118, 120 are rotated in the other direction, the unlocking drive sockets cannot be utilised for locking the valve. This is a safety feature, as use of the unlocking drive socket 119 to lock the valve could exert 10 such a compression force between the valve member 21 and the valve seat 19 that extreme torque may be necessary in order to subsequently unlock the valve (having regard to. the fact that torque requirements to unlock a valve are significantly greater than the torque requirements for locking a valve). The gear assembly 41 also includes a casing 123 which provides a protective 15 shroud about the gear train 61. The 'mounting plates 45, 47 are positioned on opposed sides of the yoke 27 a d clamped in position by way of clamping bolts 131. As the yoke 27 is a casting it may be necessary to grind the opposed faces of the casting to ensure that they are sufficiently flat in order to receive the mounting plates 45, 47. 20 The base plate 63 is attached to the mounting plates 45, 47 in a manner permitting variation to the orientation of the base plate with respect to the mounting plates. In the arrangement shown, the mounting plates 45, 47 eabh have' a mounting flange 48 to which the base plate 63 is releasably attached by mears of mounting bolts 125. The mounting bolts 125 pass through aligned b It 25 holes, in the flanges 48 and in the base plate 63. The mounting bolts 125 threadingly engage in holes incorporated in a backing 'plate 128 which is positioned against the base plate 63. The use of the backing plate 128 avoids t hle need for.a nut for each bolt 125 and thereby makes assembly easier. The base plate 63 incorporates a plurality of available bolt holes 127 through 30 which the mounting bolts 125 can pass, as best seen if Figure 8. In this way, tie WO 2008/052268 PCT/AU2007/001665 15 orientation of the base plate 63 (and that the operating mechanism 41 attached therpto) can be predetermined according to the particular bolt holes 127 selected for 'ttaching the base plate 53 to the mounting plates 45, 47. This is particularly advantageous, as it allows the overall apparatus 10 to be 5 oriented in order for the various drive sockets to be conveniently accessible to! an operator. Further, it accommodates various orientations of the valve 11. Further, because there are two operating drive sockets 104, 106 in opposed relation, and also two unlocking drive sockets 118, 120 also in opposed relation, an operator can access the operating mechanism (40) from either side therhof 10 according to what is more convenient. As ailluded to above, the valve stem 23 is restrained against rotation while allowing axial movement thereto in response to rotation of the yoke bush 29. The restraint is provided by restraint means 130 comprising a first element 131 and a second element 132. The first element 131 comprises a nut assembly 153 15 thre~dingly engaging the threaded shank of the valve stem 23. The nut assembly 133 comprises a nut section 135 threaded on the valve stem 23, and a bl ck section 137 which is fixed to the nut section and which is also fixed to the valve stem 23. More particularly, the block section 137 is fixed to the nut section 135 by cap head screws (not shown). The block section 137 is fixed to the rectangular 20 spigt portion provided at the free end of the valve stem 23 such that there is restraint against any relative rotation between the valve stem 23 and the block section 137. The second element 132 cooperates with the first element 131 ,to allow, relative displacement of the first element 131 in a direction corresponding Ito the axis of the valve stem 23 and to also block rotation of the first element 131 25 relative to the second element 132 about the axis of the valve stem. The seco d element 132 comprises a sleeve 141 which is mounted on the casing 123 and within which -the block section 137 is accommodated for sliding movement therealong, The sleeve 141 is of rectangular cross-section and the block section 137 1 of a matching cross section to allow the sliding movement therealong wh le 30 beind constrained against rotation therein.

WO 2008/052268 PCT/AU2007/001665 16 The Various'drive sockets are each adapted to receive a powered driving tool 1 0 which an operator can use to deliver driving torque thereto. The driving tool 160 can be applied to any one of the operating drive sockets 104, 106 and unlockihg drive sockets 118, 120 at the time that rotational torque is required to be delivered 5 thereto. In this embodiment, the driving tool 160 has a square drive spigot 101 for mating engagement with the various drive sockets. While the driving tool 1 0 can take any appropriate form, it is particularly convenient that it be an dir operated torque gun. In Figures 3 to 6 the driving tool 160 is shown connectedito a respective one of the various drive sockets available. 10 Reaction torque is generated duririg operation of the powered driving tool 160 ahd so it is advantageous that there be a mechanism for transferring the reaction torque away from the operator of the powered driving tool rather than the operator havirig to resist the reaction torque. For this purpose, the operating mechanism 40 further comprises a coupling 15 arrangement 170 operable- between the driving tool 160 and the operatig mechanism 40 for transferring the reaction torque away from the operator of thle powered driving tool. The coupling arrangement 170 comprises a first (fixed) coupling element 171 associated with each of the operating drive inputs 104, 106 and the unlocking drive inputs 118, 120, and a second (corresponding) coupling 20 element 172 on the powered driving tool 160. The arrangement is such that cooperation between the two coupling elements 171, 172 is adapted to allow displacement therebetween in the direction corresponding to the axis of rotation of the driving tool 160 while constraining the two coupling elements against relative rotation about the axis of rotation. With this arrangement, reaction torque arisipg 25 from operation of the powered driving tool 160 is transferred through the couplirig element 172 on the tool to the respective fixed coupling element 171. In this w y, an operator holding the powered driving tool 160 merely has to guide the tc.ol during its operation and does not have to counteract any reaction torque, Each first coupling element 171 comprise a sleeve 175 mounted on the casirjg 30 123 around the respective drive socket 104, 106, 118, 120. The second coupling element 172 comprise a block 177 which is rigidly mounted on the body 163 bf WO 2008/052268 PCT/AU2007/001665 17 the 'driving tool 160 and which is adapted to be received in the sleeve 175 for sliding movement therealong. The sleeve 175 is of rectangular cross-section and the 'block 177 is of a matching cross-section to allow the sliding movement theriealong while being constrained against rotation through interaction between 5 the sleeve 175 and the block 177 accommodated therein. The operator can access the respective drive socket though the hollow interior of the Oleeve 175 associated with the drive socket. In this embodiment, the block 177 comprises a body 179 having a central opening 181 into which part of the body 163 of the tool 160 is received, as best seen in 10 Figu res 21 and 22. The opening 181 has splines 183 which engage with match ng splihes (not shown) provided on the body 163 of the tool, Interaction between the splires fixes the block 177 against rotation relative to the tool body 163 which is held by the operator, With this arrangement, the operator merely needs to insert the tool 160 into the 15 respective sleeve 175 to engage the drive spigot 161 on the tool to the respective drive socket. In doing this, the operator needs to align the block 177 with he sleeve 175 so that the block can enter the sleeve. The block 177 is slidable along the sleeve 175 to allow engagement between the drive spigot 161 on the tool 160 and the respective. drive socket, but interaction between the block and the sleeve 20 prevents rotation of the block within the sleeve upon operation of the driving tool (whidh involves powered rotation of drive spigot on the tool to deliver rotational torque to the drive socket with which the drive spigot is engaged). It should be appreciated that the scope of the invention is not limited to the scope of the embodiment described. 25 While the embodiment has been described with respect to apparatus for modifying a drain valve, it should be understood that the invention may haye application to other valves, including both short stem valves and long stem valves.

18 Further, while the embodiment has been described with reference to modification of existing valves, the invention may also be incorporated into original equipment manufacture; that is, a valve could be constructed to incorporate the invention. 5 Modifications and changes may be made without departing from the scope of the invention. Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood 10 to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. It will be clearly understood that, if a prior art publication is referred to herein, that reference does not constitute an admission that the publication forms part of the 15 common general knowledge in the art in Australia or in any other country.

Claims

1. ;An operating mechanism for a valve having a valve body defining a val ve seat and a valve member moveable into and out of engagement with the valve seat, the valve member comprising a valve disc and a valve stem, and 5 a bush through which the valve stem extends in threaded engagement 'therewith whereby relative rotation between the bush and the valve stem causes axial displacement of the valve stem relative to the bush, the operating mechanism comprising two operating drive inputs each of which! is drivingly connected to the bush, either one of the two operating drive inputs 10 being selectively operable for delivery of torque to the bush to cau e rotation thereof about the valve stem.

2. An operating mechanism according to claim 1 wherein the two operating drive inputs are rotatable about a common axis and are disposed on 'opposed sides of the operating mechanism. 15

3. An operating mechanism according to claim 1 or 2 further comprising tvo unlocking drive inputs each drivingly connected to the bush: the drive rio !between the operating drive inputs and the bush and the drive ratio between the unlocking drive inputs and the bush being different from each other sudh that a larger torque is delivered to the bush from operation of either one of 20 the unlocking drive inputs in comparison to the torque delivered to the bush ,rom operation of the either one of the operating drive inputs for the sane torque input.

4. An operating mechanism according to claim 3 wherein the operating dri e inputs and the unlocking drive inputs are each drivingly connected to t6e 25 bush through a gear train, the gear ratio between the operating drive inputs and the bush and the gear ratio between the unlocking drive inputs and the bush being different from each other to provide the different drive ratios. WO 2008/052268 PCT/AU2007/001665 20

5. An operating mechanism according to claim 4 wherein the gear train comprises a bush drive gear adapted for connection to the bush whereby rotation of the bush drive gear imparts rotary motion to the bush.

6. An operating mechanism according to claim 5 further comprising a hub 5 adapted to be mounted on the bush for rotation therewith, the hub being configured to define the bush drive gear.

7. An operating mechanism according to claim 5 or 6 wherein the gear train comprises the bush drive gear in meshing engagement with an operating gear to which the two operating drive inputs are driving connected. 10

8. An operating mechanism according to claim 7 wherein the operating gea1 is connected to an intermediate gear for rotation therewith, the intermediate gear being in meshing engagement with a pinion to which the unlocking drive inputs are drivingly connected.

9. An operating mechanism according to claim 8 wherein each unlocking drve 15 input is drivingly connected to the pinion through a respective ratch et adapted to transmit rotational torque to the pinion upon rotation of the unlocking drive input in one direction and adapted to free-wheel uppn rotation of the unlocking drive input in the other direction so as not to transmit any rotational torque to the pinion. 20

10. An operating mechanism according to any one of claims 6 to 9 wherein the hub has a peripheral flange which is configured as a spur gear providing the bush gear.

11. An operating mechanism according to any one of the preceding claims wherein the operating gear and the intermediate gear are defined by a first 25 rotatable element having an axis of rotation and two opposed axial ends otie Of which is configured to provide a first one of the two operating drive inputs and the other of which is configured to provide a second one of the tWo operating drive inputs. WO 2008/052268 PCT/AU2007/001665 21

12. An operating mechanism according to any one of claims 8 to 11 wherein e pinion is defined by a second rotatable element having an axis of rotation and two opposed axial ends one of which is configured to provide a first one of the two unlocking drive inputs and the other of which is configured to 5 provide a second one of the two unlocking drive inputs.

13. An operating mechanism according to any one of the preceding claims further comprising means for restraining the valve stem against rotation while allowing axial movement thereof in response to rotation of the bush.

14. An operating mechanism according to any one of the preceding claims 10 wherein the operating drive inputs and the unlocking drive inputs are each adapted for engagement with a powered driving tool and wherein there is provided a fixed coupling element associated with each of the operatLng drive inputs and the unlocking drive inputs, the fixed coupling element be Ing adapted to cooperate with a corresponding coupling element on the powered 15 driving tool, cooperation between the two coupling elements being adapted to allow displacement therebetween in the direction corresponding to the axis of rotation of the driving tool while constraining the two coupling elements against relative rotation about the axis of rotation,

15. An operating mechanism according to claim 14 wherein the fixed couple ng 20 element comprises a sleeve and the second coupling element comprise' a block on the body of the driving tool adapted to be received in the sleeve for sliding movement thereaIong.

16. Apparatus for operating a valve having a valve body defining a valve seat and a valve member moveable into and out of engagement with the valve 25 seat, the valve member comprising a valve disc and a valve stem, and a bush through which the valve stem extends in threaded engagement therewith whereby relative rotation between the bush and the valve stem causes axial displacement of the valve stem relative to the bush, the apparatus comprising an operating mechanism according to any one of the 30 preceding claims and further comprising a powered driving tool for selective WO 2008/052268 PCT/AU2007/001665 22 engagement with the drive inputs for delivery of rotational torque thereto, ihe operating mechanism further comprising a fixed coupling element associa ed with each drive input, the coupling element being adapted to cooperate ith a corresponding coupling element on the powered driving tool, cooperation 5 between the two coupling elements being adapted to allow displacement therebetween in the direction corresponding to the axis of rotation of ihe driving tool while constraining the two coupling elements against relative rotation about the axis of rotation.

17. A valve comprising a valve body defining a valve seat and a valve member 10 moveable into and out of engagement with the valve seat, the valve member comprising a valve disc and a valve stem, a bush through which the valve stem extends in threaded engagement therewith whereby relative rotation 'between the bush and the valve stem causes axial displacement of the valve stem relative to the bush, and two operating drive inputs each of which is 15 drivingly connected to the bush, either one of the two operating drive inputs being selectively operable for delivery of torque to the bush to cause rotation thereof about the valve stem.

18. A valve according to claim I wherein the two operating drive inputs are rotatable about a common axis and are disposed on opposed sides of the 20 valve

19. A valve comprising a valve body defining a valve seat and a valve member moveable int& and out of engagement with the valve seat, the valve mem er comprising a valve disc and a valve stem, a bush through which the valve stem extends in threaded engagement therewith whereby relative rotat on 25 between the bush and the valve stem causes axial displacement of the valve stem relative to the bush, two operating drive inputs each of whichI is drivingly connected to the bush, either one of the two operating drive inpLts i being selectively operable for delivery of torque to the bush to cause rotation thereof about the valve stem, and two unlocking drive inputs each of which is 30 t drivingly connected to the bush, the drive ratio between the operating drive inputs and the bush and the drive ratio between the unlocking drive inputs 23 and the bush being different from each other such that a larger torque is delivered to the bush from operation of either one of the unlocking drive inputs in comparison to the torque delivered to the bush from the either one of the operating drive inputs for the same torque input. 5

20. A valve according to claim 19 wherein the two operating drive inputs are rotatable about a common axis and are disposed on opposed sides of the operating mechanism. 10

21. A valve according to claim 19 or 20 wherein the two unlocking drive inputs are rotatable about a common axis and are disposed on opposed sides of the operating valve.