AU648164B2 - Apparatus or plant for cleaning anode blocks of anode assemblies used in electrolytic smelting - Google Patents

Description

1

AUSTRALIA

PATENTS ACT 1990 648 1 6 4 C OMP T.E T RPErTFICATTON FOR A STANDARD PATENT

ORIGINAL

.9 9 9 *9 5* 9 Name of Applicant: Actual Inventor: Address for Service: Invention Title: WESTFALIA BECORIT INDUSTRIETECHNIK GmbH Erfried Simon SHELSTON WATERS Clarence Street SYDNEY NSW 2000 "APPARATUS OR PLANT FOR CLEANING ANODE BLOCKS OF ANODE ASSEMBLIES USED IN ELECTROLYTIC

SMELTING"

r The following statement is a full description of this invention, including the best method of performing it known to us:- APPARATUS OR PLANT FOR CLEANING ANODE BLOCKS OF ANODE ASSEMBLIES USED IN ELECTROLYTIC SMELTING The present invention relates to apparatus or plant for cleaning residual anode blocks on anode rods which form anode assemblies used in electrolytic baths.

It is well known that during aluminium smelting, for example, in electrolytic furnaces the carbon anodes become coated with aluminium oxide and solidified melt.

It is necessary to clean off the incrustations and coatings to enable the partly consumed anode blocks to be recovered and used to recycle new carbon anode blocks.

10 A known apparatus for cleaning anode blocks is described in US patent specifibation 4514873. In this :apparatus, the anode assemblies are transported in succession to a breaker with pivotal cutting blades which detaches incrustations and coatings of solidified melt 15 from the anode blocks. The cleaned anode blocks can then be recovered to produce new carbon anode blocks as is desired, while the detached coating material can be returned to the furnace. it is essential to ensure the anode blocks are cleaned thoroughly to remove the coatings and this can only be achieved by subjecting the anode assemblies to successive cleaning stages.

A general object of this invention is to provide an improved form of cleaning apparatus or plant.

According to the invention there is provided apparatus for cleaning coatings and incrustations of solidified melt on the residual blocks of anode assemblies used in electrolytic furnaces; said apparatus comprising a raisable and lowerable support which can be raised to engage and lift the assemblies in turn, a holding mechanism with an adjustable vertically disp ble clamping device having at least one location 10 means which cooperates with the support to locate and hold the assembly on the raised support and breaking means for breaking off the coatings and incrustations from the block of the assembly held between the holding device and the support.

Preferably there is at least one cleaning chamber defined by framework which contains the support, the holding mechanism and the breaking means.

In contrast to the known apparatus, the provision 'of the holding mechanism with its adjustable clamping device which can be set against an anode rod end piece and which cooperates with the raisable and lowerable support or table enables the anode block to be reliably releasably held while the coatings thereon are removed by impact tools rather than cutting blades. Preference is given to a pneumatic or hydraulic hammer operating one or more chisels as the impact tools.

The apparatus can be arranged as is known with each anode assembly being transported through the apparatus with the aid of a suspended-rail type conveyor.

The clamping device may employ separate stops which engage positively with the ends of the anode rod end piece from which project nipples or projections embedded o in the associated residual anode block.

10 Preferably, there are several cleaning stations with holding mechanisms and devices which permit the blocks to be subjected to successive cleaning operations.

During the breaking off of the coatings with the 1 impact tools, the positioning and fixing of the 15 anode assembly can be effected laterally from one side.

The clamping device can be realised as a forkshaped plate with prongs engaging on opposite sides of r the anode rod and a hook or claw-like plate acting as a •,og o locator or stop on the underside. Preference is given to a design in which there are a pair of stops each with a central faces adapted to mate against end faces of the end piece of the anode rod. The anode assembly end piece usually has several, e.g. six, nipples around which the anode block is formed. The stops are conveniently detachably fixed to the underside of the holding device for release and exchange.

The support table can be raised and lowered on a slider and is best supported on an arm linked to the slider with a ball-and-socket joint. In this way, the table has a considerable flexibility of movement and it can adapt itself to irregular shapes or contours on the underside cZ the residual blocks.

e If the initial cleaning is carried out by hammer 10 means, it is advisable to mount this means on a carriage which is guided for lateral movement on an upright S• framework of the apparatus so that the hammer tools can be removed from the site of action or introduced from the exterior.

15 If cleaning is carried out by hammers, as aforesaid, in a preliminary station, a subsequent e oo supplementary cleaning action involving other tools such as shears can be adopted.

To avoid noise and dust, the cleaning station or each of these stations can be disposed in a chamber under a roof wall with a slot for accepting the anode rods.

A conveyor in the bottom of the chamber can then transfer the detached coating material. The chamber can be sealed and connected with a suction line to draw off dust.

The apparatus can be composed of two parallel sections each with one or more cleaning stages as aforesaid.

The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description.

An embodiment of the invention will now be 10 described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a plan view of cleaning apparatus constructed in accordance with the invention; Figure 2 is an end view of the apparatus shown in 15 Figure 1; Figure 3 is an enlarged end view of part of the apparatus shown in Figures 1 and 2; Figure 4 is plan view of the hold down device of oo* the apparatus; Figure 5 depicts a stop detached from the hold down device; and Figure 6 is a side view of part of the apparatus showing an individual anode rod suspended from the rail conveying system.

6 The cleaning apparatus shown in the drawings has two operating sections I and II of identical design disposed parallel to one another. Each section I,II is controlled independently from a cabin 1 where an operator has a control panel. The sections I,II are conveniently provided with a common framework 12 which encloses the cabins 1. A suspended rail conveyor leads through the upper region of each section I,II. Figure 6 shows the S: conveyor with a rail 2 on which a carriage or trolley 3 runs. The carriage 3 has a chain tackle 4 with a coupler 6 to which an anode rod 5 to be treated is fixed with a pin or bolt 7. The rod 5 joins with a lower end piece 8 which has six projections or nipples 9 embedded in a residual anode block 10. The original shape of the complete anode block 10 is indicated with broken lines in Figure 6.

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The anode block 10 which has been removed from an electrolytic melt bath carries a coating 11 of solidified melt on its upperside and this coating 11 must be removed completely to enable the carbon of the anode block 10 to be recovered.

As shown in Figure 1, each section I,II has, within the common upright framework 12, a preliminary cleaning station A and a subsequent cleaning station B.

In the framework 12, there is a top wall 13 with a central slot 14 which guides the anode rods 5 moving along the conveyor rail 2 with the trolleys 3. Beneath the wall 13 in a chamber of the station A there is a lifting device with a support table 15 and above the table 15 there is a holding mechanism 16 with a clamping device 27. Between the support 15 and the holding mechanism 16 there is a breaking device 18 on the framework 12 for releasing the coatings 11 from the anode blocks 10. The anode block 10 to be treated is clamped on the table 15 with the device 27, while the coating 11 is detached with the device 18." As shown in particular in Figure 3, the table 15 is mounted on a ball-and-socket joint 19 for swivelling in all directions. The joint 19 is provided on an arm located on a slider 21. The slider 21 is mounted and guided in the framework 12 for raising and lowering and an hydraulic ram 22 serves to move the slider 21.

20 The breaking device 18 has a carriage 23 which carries one or more hydraulic hammers 24 with impact tools in the form of chisels 25. The or each hammer 24 is preferably enclosed in a jacket or housing to reduce the noise levels. The carriage 23 is itself 8 displaceable on a part 26 of the framework 12 in a transverse horizontal sense and is moved with one or more hydraulic units. The or each hamme:c 24 is disposed outside the working chamber of the cleaning station A.

The location of the hammer 24 and the support table 15 as the coating 11 is detached and released is shown in chain-dotted lines 24' and 15' in Figure 3.

The plate-like clamping device 27 of the holding mechanism 16 is pivotably mounted for swinging vertically 10 on a pivot joint 28 of a bracket 29 on the framework 12.

A pair of hydraulic or pneumatic units 30 have their cylinders articulated with joints 31 on the bracket 29 while the piston rods are articulated with joints 33 on the upper region of the device 27. These units 30 serve to swing the device 27 about the joint 28.

As shown in Figute 4, the device 27 is substantially bi-furcated or fork-shaped in plan view with two prongs 34 spaced apart with a clearance space sufficient to permit the prongs 34 of the device 27 to be moved either side of the anode rod 5. Stops 36 indicated in chain-dotted lines in Figure 4 are positioned on the underside of the device 27 in the region of the prongs 34. Figure 5 shows one of the stops 36 separately to the device 27. As shown the stop 36 takes the form of a hook-shaped plate with two contact faces 37,38 inclined to one another. The downwardlydirected face 38 extends via a ramp 39 to a tip 40. Each stop 36 is releasably fitted to the underside of the device 27 by screws engaging in threaded holes 41. The design and arrangement of the stops 36 is largely dictated by the shape of the end piece 8 of the anode rod The device 27 is merely shown in a schematic outline in Figure 6 as swung down to its working position. It 10 can be seen here that the stops 36 engage with their contact faces 37,38 against faces 42,43 at the ends of the end piece 8, thereby to support the anode block assembly 10,5.

.Figure 1 shows the anode rod 5 equipped with six 15 nipples at the leCa-hand side in the section II. The device 27 is not shown for the sake of clarity but in Figure 2, the device 27 is shown in the operating section I. At the upper side of the wall 13 of each section I,II there is a guiding and centering device which has a bi-furcated support 44 which can be displaced with a ram to engage with the anode rod 5 to prevent the rod from swinging around.

Figure 2 also shows a conveyor 46 which collects and transfers material released from the coatings 11 detached from the anode blocks 10. The released coating material is guided onto the conveyor 46 with the aid of individual funnel-like walls 47,28 and the material is transferiad along the conveyor 46. The walls 47 can be on the slider 21 or the lifting arm 20 as shown in Figure 3. The chambers beneath the walls 13 are sealed off from the exterior to prevent the release of dust and seals can be provided on the guides 44 in order to close the chambers from the top.

10 During use, the anode rods 5 removed from the electrolytic melting baths and carrying the blocks 10 of residual anode carbon are fed to the preliminary cleaning stations A of the sections I,II by means of the trolleys 3 running along the rails 2. The anode rods 5 are e.

guided in the slots 14 in the walls 13. With the suspended conveyor stationary, the fork 44 is pushed over the rod 5 to be located to fix the latter in a lateral sense. The table 15 is then raised by the ram 22 until the table 15 strikes the underside of the block 10 and lifts the anode rod 5 and the block 10 together into a position where the coating 11 can be attacked with the impact tool 25 as the hammer 24 performs its hammering action. Before the tool 25 operates, however, the device 27 is pivoted downwards to engage with the stops 36 11 against the end piece 8 of the rod 5. The anode block with the end piece 8 is thereby rigidly clamped between the table 15 and the device 27 so that the coating 11 can be reliably detached with the impact tool 25. The detached coating material falls onto the conveyor 46 and can be transferred and collected. Once the coating 11 has bee.. removed, the table 15 is lowered and the device 27 is swung upwards. The anode rod 5 is moved on with the conveyor 2,3 to bring the anode 5 and the anode block 10 10 into the station B where any residual coating 11 can be removed by a suitable tool or tools designated 50 in Figure 1. In the embodiment shown the tool 50 takes the form of cutting shears similar to US Patent specification 4514873. The subsequent cleaning carried out in the 15 station B also involves holding the rod 5 with the residual anode block 10 in a fixed position for treatment with the tool or tools 50. The combination of the support table 15 and the device 27 can also serve to, nold the assembly 10,5 during the treatment in the station B.

After the treatment, the anode rod 5 with the residual anode block 10 is taken out of the apparatus for further treatment. The stations A,B in each section are best provided with inlet and outlet doors which are held shut during the cleaning process.

Instead of having one common anode block on the nipples of the anode, it is possible to have individual anode blocks 10 on some or all of the nipples as represented in Figure 1 in section II. Here, the anode rod 5 has three nipples for each block The apparatus as described can be adapted for automatic control.

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Claims (12)

1. Apparatus for cleaning coatings and incrustations of solidified melt on the residual blocks of anode assemblies used in electrolytic furnaces; said apparatus comprising a raisable and lowerable support which can be raised to engage and lift the assemblies in turn, a holding mechanism with an adjustable clamping device having at least one location means which cooperates with .the support to locate and hold the assembly on the raised support and breaking means for breaking off the coatings 10 and incrustations from the block of the assembly held between the clamping device and the support.

2. Apparatus according to claim 1, wherein the o. support is in the form of a table. S" 3. Apparatus accordinr to claim 1 or 2, wherein a suspended rail conveyoi is provided to transport a succession of assemblies through the apparatus.

4. Apparatus according to claim 1, 2 or 3 wherein the clamping device is pivotally mounted and means is provided for bringing the device to a working position where it engages the assembly on the support. Apparatus according to claim 4, wherein the clamping device is a fork-shaped plate with prongs for engaging either side of the anode rod of the assembly and the locating means is a stop on the underside of the plate.

6. Apparatus according to claim 5, wherein there are two stops, one associated with each prong, and the stops are hook or claw-shaped with contact faces which match end faces of an end piece of the anode rod provided with nipples around which the anode block is formed.

7. Apparatus according to claim 6, wherein the end faces of each stop are set at an angle to one another. S. 8. Apparatus according to claim 5, 6 or 7, wherein the stop or each of the stops is detachably fixed to the clamping device.

9. Apparatus according to any one of the preceding claims, wherein the breaking means comprises at least one hammer with an impact tool. Apparatus according to claim 9, wherein the hammer is mounted on a carriage which is displaceable laterally relative to the support. 11i. Apparatus according to claim 10, wherein a cleaning chamber in which the support, the clamping device and the breaking means operate is defined by framework including an upper wall which has a guide slot for guiding the anode rods of the assemblies.

12. Apparatus according to claim 10 or 11, wherein the breaking means is arranged at one side of the chamber.

13. Apparatus according to claim 10, 11 or 12, wherein the chamber is sealed off and is connectable to a suction line to draw off dust.

14. Apparatus according to any one of the preceding claims wherein the support is mounted on an arm connected to a raisable and lowerable slider with the aid of a ball-and-socket joint.

15. Apparatus according to Claim 10, 11, 12, 13, or 14 6 and further comprising a further cleaning station for cleaning the assemblies after the first-mentioned 6* cleaning station.

16. Apparatus according to anyone of Claims 10 to and arranged to treat the assemblies in two parallel operating sections, each transporting the assemblies through said cleaning station or stations.

17. Apparatus substantially as described with *666 reference to, and as illustrated in, any one or more of the Figures of the accompanying drawings. DATED this 30th. Day of April, 1992 WESTFALIA BECORIT INDUSTRIETECHNIK GmbH Attorney:' IAN ERNST Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS APPARATUS OR PLANT FOR CLEANING ANODE BLOCKS OF ANODE ASSEMBLIES USED IN ELECTROLYTIC SMELTING ABSTRACT Apparatus for removing solidified electrolytic melt coatings (11) from anode blocks (10) of anode assemblies 10) has a chamber defining a cleaning station through which the anode assemblies (5,10) are transported with a suspended rail conveyor A table (15) in the chamber is raised to lift the anode assembly 10) to a position where an impact tool of a breaker (24) can detach the coatings A clamping device (27) of a mechanism (16) is swung down to engage either side of the anode rod of the assembly and to locate and clamp the assembly against the table while the breaker (24) operates. Figure 3.