ANODE BLOCK REMNANT BREAKER

Abstract: Apparatus for breaking away the remnant of an anode block from stubs of an anode rod has downwardly movable push members (23, 24) for pushing on the top surface of the anode block and means (11) for restraining the anode rod from descending while said push members push the block. To provide for secure restraint of the anode rod from descent, and achieve removal of the remnant with minimum breakage, the push members (23, 24) are two longitudinally extending push beams which engage the anode block on respectively opposite sides of the anode rod, and the means (11) for restraining the anode rod from descending is at least one stop element movable into a location between the stubs of the anode rod and above the level of the push beams (23, 24).

Description: ANODE BLOCK REMNANT BREAKER The invention relates to an apparatus for breaking away the remnant of an anode block on stubs of an anode rod. In the electrolysis of alumina to aluminium, use is made of carbon anodes which are suspended on an anode rod by means of, for example, two stubs of a Y-piece (also called a breech piece or fork piece) at the lower end of the anode rod which is fixed to the current-carrying conductor. After for example about 26 days an anode block is worn out, and the block must be exchanged for a new block. The remnant of the anode block which is on the Ypiece must be broken away from the Y-piece. However, because the residual value of the large carbon fragments is higher than that of small ones, it is important to release the anode block from the breech piece as far as possible as a whole, or in the largest possible fragments. NL-A-6903190 (corresponding to GB-A-1269809) shows apparatus for breaking an anode block remnant away from the anode rod which is also intended to break the remnant up, for which purpose crushing teeth are provided. To break the block away, two pairs of movable clamping assemblies grip the stubs of the anode rod frictionally, while the clamp members each carry a downwardly movable pushing disc. There are thus four discs, acting at spaced parts of the anode block. The present invention has as its object the removal of the anode block in one piece or as large pieces as possible. Furthermore it is sought to avoid the disadvantage of frictional gripping of the anode rod and to make possible a relatively simple construction which is able to accommodate the high forces which may arise. The invention 'is set out in claim 1. It appears that by use of the apparatus of the invention the anode blocks can remain almost entirely intact and so retain the maximum possible residual value. Preferably the apparatus has a hoist, for moving the anode rod vertically, suspended from the hoist. Preferably also the apparatus has a frame and two carriages which can be moved on the frame horizontally towards or away from each other and each having, on the ends which is opposed to the other front member, a front member, the push beams being mounted so as to move vertically oh the respective front members, and there being a guide channel in one of the front members for guiding the stop element. This construction has the advantage that at least on one side, the high separation forces act within the structure of the front member. An embodiment of the invention will now be described by wayaof example with reference to the accompanying drawings, in which: Fig. 1 is a top view of the apparatus embodying the invention, Fig. 2 is a side view of the apparatus of Fig. 1, Fig. 3a shows a section (on line 3a-3a in Fig.4) and Fig. 3b a side view of parts of the apparatus of Fig. 1 on a larger scale, and Fig. 4 is a front view of the part shown in Fig. 3a. Referring to the drawings, at a suitable distance below a mono-rail track from which the anode rod is suspended and which, with the rod, is not shown, there is installed the apparatus embodying the invention shown in Figs. 1 and 2. The apparatus comprises a horizontally and vertically extending rectangular frame 1, within which two horizontally movable breaking carriages 2 and 3 can travel simultaneously, being moved by respective carriage cylinders 4 and 5, between vertical carriage guides 7 (Fig. 2) in the form of two pairs of freely moving rollers mounted on the frame 1. As may be seen from Figs. 1 and 2, the breaking carriages 2 and 3 can be moved towards and away from each other over a certain distance. Fig. 1 shows that the breaking carriages 2 and 3 are also guided horizontally by horizontal carriage guides 6 in the form of two pairs of freely moving rollers mounted on the frame 1. At their inner, opposed ends the breaking carriages 2, 3 each carry a front member in the form of a large front plate 8, 9 and in the space between these two front plates 8, 9 a vertically movable hoist, not shown, can raise or lower the anode rod suspended from it, when the carriages 2 and 3 are moved apart. A rod guide 10 fixed to the frame 1 prevents the suspended anode rod from swinging excessively. Figs. 3a, 3b- and 4 show the front plates 8 and 9 on a larger scale. The front plate 8 carries a horizontally movable stop element in the form of a flat rectangular rod or peg 11 which is horizontally moved by a cylinder unit 12 mounted fixedly on the breaking carriage 2. The peg 11 can move horizontally in a guide channel 13 which is formed in the front plate 8 and a forward extension thereof. This construction is suitable for an anode block with two or four stubs. Two pairs of bearing blocks 14 and 15 are mounted on each of the front plates 8 and 9, and a pair of guide rods 17 and 18 are movable vertically in the bearing blocks. These rods 17 and 18 are connected, between pairs of blocks 14 and 15, by a transverse yoke-shaped connecting assembly of plates 16, which assembly is fixed at its extremities to a pair of vertically acting hydraulic cylinder units 20 and 21. The piston rods of these cylinders 20 and 21 are mounted at 25 on the front plate. At their lower ends, below the bearing block 15, the guide rods 17 and 18 together carry a horizontally extending push beam 23, 24. Each front plate is provided on its rear side with a vertical adjustment screw 26 for height adjustment relative to the track of the breaking carriages 2 and 3. In operation, when an anode rod with two stubs and a Y-piece (not shown), with the side surfaces of the Y-piece parallel to the front plates 8 and 9, is lowered, the carriage cylinders 4 and 5 are first actuated so that the breaking carriages 2 and 3 move towards each other over a given distance and come to rest with the front plates 8 and 9 at a mutual separation which is a little greater than the width of the anode block. If the anode rod is now correctly positioned with the gap between the stubs of the Y-piece in front of the peg guide channel 13, the peg 11 is moved into this gap by actuation of the peg cylinder 12. Then the four pushing cylinders 20 and 21 are actuated so that the two push beams 23 and 24 are pressed downwards onto the top surface of the anode block (which is below the peg 11) by the connecting plates 16 and the guide rods 17 and 18. This results in the rod with the anode remnant being pressed downward until the Y-piece meets the peg 11 which restrains it from descending. Thus in principle the beams 23, 24 engage the anode block over a substantial length extending beside and preferably the full length of the Y-piece. The anode remnant is now pushed off the Y-piece and falls as a whole into a tray installed under the breaker. Because the high-separation forces which act between peg 11 and peg guide channel 13 on the one hand and the push beams 23 and 24 on the other hand act internally, that is to say within the structure of the front plates 8 and 9, and the relevant components are of robust construction, no deformations of the guides occur and no forces act externally. The bottom faces of the push beams 23 and 24 are inclined downwardly towards their inner edges, i.e. the beams are of trapezoidal shape as shown in Fig. 3, so that when they are pressed downwards the greatest force is exerted on the top of the anode block as close as possible to the two sides of the stubs of the Y-piece. When the anode remnant has been pushed off th & Y-piece, the anode rod is drawn upwards slightly and any residue which remains behind in the Y-piece aperture is now removed. Then the hydraulic cylinders 20 and 21 are actuated in reverse and the peg 11 is drawn back into the channel 13, after which the breaker carriages 2 and 3 are moved apart again by the appropriate actuation of the two carriage cylinders 4 and 5 respectively. The anode rod with the now bare Y-piece can be raised by the hoist and removed via the mono-rail. Although the anode remnant breaker in the embodiment here depicted and described is suitable for the case in which the anode block is connected to the anode rod by means of only two stubs (of a Y-piece), the present invention is not limited to this case, since the principle behind the invention is equally applicable to other known types of anode block with three, four or six stubs. With anode blocks with three or six stubs (two rows of three), two stop pegs which can be moved in parallel are required; for an anode block with four stubs (arranged in a square) one stop peg is sufficient.

Claims: CLAIMS 1. Apparatus for breaking away the remnant of an anode block from stubs of an anode rod, the apparatus having downwardly movable push members (23, 24) for pushing on the top surface of the anode block and means (11) for restraining the anode rod from descending while said push members push the block characterised in that said push members (23, 24) are two longitudinally extending push beams which engage the anode block on respectively opposite sides of the anode rod and said means (11) for restraining the anode rod from descending is at least one stop element movable into a location between the stubs of the anode rod and above the level of the push beams (23, 24). 2. Apparatus according to claim 1 further including a hoist for vertically moving the anode rod, suspended from the hoist. 3. Apparatus according to claim 1 or claim 2 having a frame and two carriages (2, 3) movable on the frame towards and away from each other horizontally and each having a front member (8, 9) on its end opposed to the other carriages, the two push beams (23, 24) being respectively mounted on said front members for vertical movement relative thereto, and the stop element (11) being located in a guide passage (13) in one of the front members. 4. Apparatus according to any one of claims 1 to 3 wherein said push beams (23, 24) have inclined bottom faces, with in each case the lower edge at the side of the beam facing the other beam.

Inventors: DIETVORST, PETRUS JOHANNES, MEKKERING, HENDRIK
Applicants: ALUMINIUM DELFZIJL B.V.
Application year: 1985
Main classification: C25C3
IPC codes: C25C3