AU2007350649A1

AU2007350649A1 - Sealing apparatus for an aluminium smelter

Info

Publication number: AU2007350649A1
Application number: AU2007350649A
Authority: AU
Inventors: Angelo Marcel Maximilian Pedonese
Original assignee: PEDONESE SERVICES Pty Ltd
Current assignee: PEDONESE SERVICES Pty Ltd
Priority date: 2007-04-03
Filing date: 2007-08-02
Publication date: 2008-10-09
Also published as: WO2008119100A1

Description

WO 2008/119100 PCT/AU2007/001080 Sealing apparatus for an aluminium smelter Field of the invention This invention relates to apparatus for providing a seal at a penetration region on a 5 wall of a structure through which an object passes. The invention finds application in the process of aluminium smelting however it could be applicable to other processes and apparatus where a seal may be required at a penetration region of the apparatus. Background of the invention 10 Aluminium smelters are used to extract the aluminium from alumina ore and in one form comprise a vessel into which the alumina is fed. The aluminium and other materials are subjected to an electric current which generates sufficient heat to maintain the alumina in a molten condition so as to enable the separation of the aluminium. The electric current is produced by an electric system which includes an anode which is disposed within the 15 vessel. The anode is supported by an anode stem which extends through a penetration region in a wall or hood of the vessel. The extraction process produces toxic fumes which need to be extracted from the vessel. The smelter is usually provided with a fume extraction system which facilitates safe removal of most of the fumes. There is however the potential for the escape of fumes at the penetration region. 20 The present invention seeks to provide apparatus which can reduce escape of toxic gases in the penetration region. Summary of the invention According to one aspect of the present invention there is provided apparatus 25 suitable for use in an aluminium smelter, the smelter including a vessel having a hood or vessel wall with a penetration region therein through which an anode stem can pass so as to extend into the vessel, the apparatus providing an at least partial seal for the anode stem at the penetration region and including a wall assembly which includes a plurality of wall sections, a locating zone which is at least partially bounded by the wall sections and 30 through which the anode stem can pass the wall sections being adapted for movement between an installation position in which the anode stem can be received within the WO 2008/119100 PCT/AU2007/001080 -2 locating zone and a sealing position in which the wall sections can at least partially border the anode stem in close proximity thereto. The arrangement is such that when the wall sections are in close proximity to the anode stem when installed the escape of toxic gases through the penetration region is substantially reduced. 5 In one form the wall assembly may include first and second said wall sections which are disposed on opposite sides of the locating zone. Preferably the first and second wall sections are each mounted for pivotal movement at respective pivot mounts so that the wall sections can each pivot about the pivot mounts towards and away from each other between the installation and sealing positions. The apparatus may further include an 10 adjustment device for one or both wall sections which enables limited movement of the or each wall section relative to the mounting associated therewith. The or each adjustment device may include an elongated slot in the wall section which receives the pivot mount therein enabling limited relative movement between the wall section and its associated pivot mount along the slot. The adjustment devices are such that they compensate for any 15 lateral misalignment of the anode stem during installation thereof. The arrangement of the slots and pivot mounts provide for limited displacement of the wall sections relative to the pivot mounts to try and ensure paper alignment of the wall sections relative to the anode stem. The apparatus may further include a biasing device which urges the wall sections 20 into the sealing position. The biasing device may be in the form of a spring associated with each wall section. The wall assembly may further include an end wall section which extends between the first and second wall sections and is mounted for lateral linear displacement towards and away from the locating zone. Preferably the end wall section is operatively connected 25 to the first and second wall sections such that lateral displacement of the end wall section in one direction causes one or both of the first and second wall sections to move into the installation position. The operative connection may be by way of motion control coupling which includes a stop on one or both end wall sections which engages with a lever on one or both the first and second wall sections to cause said movement. A biasing device such 30 as a spring may be provided to urge the end wall section in the direction of the locating zone.

WO 2008/119100 PCT/AU2007/001080 -3 The apparatus may further include a base section to which each of the wall sections are mounted. The base section and wall sections may be generally flat plate-like elements. Preferably a side edge portion of each wall section provides the seal region of the apparatus. 5 The wall assembly may further include deflectors associated with each wall section which are adapted to deflect the wall section if struck by the anode or anode stem during installation. Preferably the deflectors are arranged at the aforementioned edge portions of the wall sections. To install the anode, it is lowered through the penetration region until it is at least 10 partially immersed in the alumina. The anode stem is then moved laterally so as to be clamped against a busbar. The lateral movement forces the anode stem into the inner end region of the locating zone, against the end wall section, forcing the end wall section to retract. During the lateral movement of the anode stem, the stops mounted on the end wall move laterally with the end wall section, which frees the other wall sections to swing about 15 the pivot under the biasing influence of the spring to adopt a sealing position, flat against adjacent walls of the anode stem. Description of a preferred Embodiment Preferred embodiments of the invention will hereinafter be described with 20 reference to the accompanying drawings and in those drawings: FIG. 1 is a schematic front elevation of an aluminium smelter; FIG. 2 is a section view through A-A of the aluminium smelter; FIG. 3 is a plan detail view of portion B; FIG. 4 is a plan view of a seal apparatus in an installation position; 25 FIG. 5 is a plan view of the seal apparatus in a sealing position; and, FIG. 6 is a front elevation view of the seal apparatus in the sealing position. Referring to figures 1 to 3 there is shown an aluminium smelter including a smelting pot 100 containing molten alumina 98. As best seen in FIG 2 the smelting pot 100 includes a hood 90 which has a hood ceiling 94 and removable sealing access panels 30 97. An extraction passage 95 is provided for extraction of noxious gases produced during smelting.

WO 2008/119100 PCT/AU2007/001080 -4 An anode 99 is shown immersed in the alumina 98, the anode 99 mounted on an end of an anode stem 8. The anode stem 8 extends through the hood 90 at a penetration region 5 and is square in section, having walls 2, 6, 7 and 9. Wall 6 is electrically connected to a busbar 96 and removably clamped thereto by clamp 93. 5 Referring more particularly to figures 4-6 there is shown a seal apparatus generally indicated at 10 which is suitable for sealing the penetration region 5. The seal apparatus 10 includes wall assembly comprising a plurality of wall sections 12 forming a locating zone 3 which provides a seal at the penetration region 5 on three sides of the anode stem 8. The wall section 12 include a first wall section 14 and a second wall section 16, the first and 10 second wall sections being spaced apart and disposed on opposite sides of the locating zone 3. The first and second wall sections are pivotally mounted and are adapted to pivot about pivot mounts 34 and 36 respectively. An end wall section 18 is provided which extends between the wall sections 14 and 16, and is disposed at an inner side of the zone 3. The seal apparatus 10 is adapted to move between a sealing position in which the 15 wall sections 12 are proximal or in abutment with the anode stem 8, and an installation position in which the wall sections 14 and 16 are disposed distal the anode stem 8. Wall sections 14, 16, and 18 are biased to the open position by biasing devices 44, 45 and 50, in the form of springs, respectively, 46, 47 and 52. Adjustment devices 42 are provided to compensate for any lateral misalignment of 20 the anode stem 8 when installed. The adjustment devices 42 are in the form* of elongate tracks or slots 38 and 39 so that, in the case of a misaligned anode stem 8, the respective pivots 34 and 36 follow in the tracks 38, 39 to laterally move one wall section 14 or 16 and simultaneously extend the other to maintain the jaws in a parallel disposition relative to an adjacent anode stem wall which facilitates a seal between the wall sections 14 and 16 and 25 the anode stem 8. Guides 80 are provided so that end wall section 18 is maintained in a parallel disposition relative to anode stem wall 6 during extension and retraction so as to facilitate a seal when in abutment therewith. A motion control apparatus 20 is provided which links the wall sections 14, 15 and 30 17 together so that movement of end wall section 18 causes movement of wall sections 14 and 16. The apparatus 20 includes two stops 22 and 24 which, due to the springs 46, 47, WO 2008/119100 PCT/AU2007/001080 engage or abut the wall sections 14 and 16 so that when the end wall section 18 slides, wall sections 14 and 16 are caused to pivot. This preferred arrangement provides a type of automatic operation, wherein when the anode stem 8 is released from the penetration region 5, the end wall section 18 extends into the penetration region 5. The extension of 5 end wall section 18 pushes the stops 22, 24 against the wall sections 14 and 16 so that they adopt a retracted or open position. A deflector 60 is provided to minimise damage to wall sections and to facilitate the movement of the adjusters 42. The deflector 60 is in the form of a round bar 64 mounted on an edge of each of the wall sections 12 so as to gently deflect walls 12 to a retracted 10 position if bumped by the anode stem 8 during installation. The deflector 60 generally conforms in section shape to anode stem walls 6, 7, and 9 so as to facilitate sealing; in the drawings deflectors 60 are straight to correspond with flat walls of anode stem 8. A base 40 is provided in the form of a flat pate 41. Preferably all components are generally flat to provide a low profile to reduce interference with loading anode 8. The 15 pivot mounts 34, 36 are mounted on the base 40. The base 40 is bolted to an upper surface of the hood ceiling 94. To install an anode 99, the removable sealing panels 97 are removed from the pot 100. The anode 99 is lowered into the penetration 5 until it is immersed in the molten alumina 98. The anode stem 8 is then moved laterally so that it may be clamped against 20 busbar 96. During the lateral movement, the anode stem wall 6 abuts end wall section 18 of the seal apparatus 10 at the deflector 60 and pushes end wall section 18 back deeper into the bight 3. The lateral movement moves stops 22 and 24 laterally with the end wall section 18 so that walls 14 and 16 are swung closed under the bias of the spring 44, 46 until they abut the anode stem 8 substantially parallel with anode stem walls 7 and 9. The 25 removable sealing panels are then replaced to seal the penetration 5 at anode stem wall 2. During the forcing of the anode stem into the end of the locating zone, the wall sections 14 and 16 can automatically correct for any lateral offset of the anode stem 8 by the action of the pivot 34 and 36 moving along guides 38, and 39. The pivot 34 may retract along guide 38 if there is lateral misalignment towards that side, and the other jaw 30 extends into the bight to compensate. In order to release the anode stem from the pot 100, the removable sealing panels WO 2008/119100 PCT/AU2007/001080 -6 97 are removed. The anode stem 8 is then unclamped and moved laterally away from the busbar which causes end wall section 18 of the seal apparatus 10 to move laterally into the penetration region under the influence of springs 52. The wall sections 14 and 16 are then forced to pivot open by the stops 22 and 24 until they hit opening stops 70 and 71. 5 Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or ambit of the invention. 10 15

Claims

1. Apparatus suitable for use in an aluminium smelter, the smelter including a vessel having a hood or vessel wall with a penetration region therein through which an anode 5 stem can pass so as to extend into the vessel, the apparatus providing an at least partial seal for the anode stem at the penetration region and including a wall assembly which includes a plurality of wall sections, a locating zone which is at least partially bounded by the wall sections and through which the anode stem can pass, the wall sections being adapted for movement between an installation position in which the anode stem can be received within 10 the locating zone and a sealing position in which the wall sections can at least partially border the anode stem in close proximity thereto.

2. Apparatus according to claim 1 including first and second said wall sections which are disposed on opposite sides of the locating zone. 15

3. Apparatus according to claim 1 or claim 2 wherein said first and second wall sections are each mounted for pivotal movement at a respective pivot mount so that the wall sections can each pivot about the pivot mounts towards and away from each other between the installation and sealing positions. 20

4. Apparatus according to claim 3 including an adjustment device for one or both wall section which enables limited movement of the or each wall section relative to the pivot mount associated therewith. 25

5. Apparatus according to claim 4 wherein the or each adjustment device includes an elongated slot in the wall section which receives the pivot mount therein enabling limited relative movement between the wall section and its associated pivot mount along the slot.

6. Apparatus according to any preceding claim further including a biasing device 30 which urges the wall sections into the sealing position. WO 2008/119100 PCT/AU2007/001080

7. Apparatus according to any one of claims 2-7 wherein said wall assembly further includes an end wall section which extends between said first and second wall sections and is mounted for lateral linear displacement towards and away from the locating zone. 5

8. Apparatus according to claim 7 wherein said end wall section is operatively connected to said first and second wall sections such that lateral displacement of said end wall section in one direction causes one or both said first and second wall sections to move into the installation position. 10

9. Apparatus according to claim 8 including a biasing device which urges said end wall section in a direction opposite to said one direction.

10. Apparatus according to claim 9 wherein said operative connection is by way of 15 motion control coupling which includes a stop on one or both end wall sections which engages with a lever on one or both the first and second wall sections to cause said movement.

11. Apparatus according to any preceding claim including a base section to which each 20 of the wall sections are mounted.

12. Apparatus according to claim 11 wherein the base section and wall section are generally flat plate-like elements. 25

13. Apparatus according to any preceding claim wherein the wall assembly includes deflectors associated with each wall section which are adapted to deflect the wall section if struck by the anode or anode stem during installation.