US2121578A - Means for adjusting the electrodes of electric furnaces - Google Patents

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E. WINTER ET AL June 21, 1938.

MEANS FOR ADJUSTING THE ELECTRODES OF ELECTRIC FURNACES Filed July 16, 1957 Ill/l/I/l/l/l/l/l/l/A Ernst Wnber Franz LLZc/(erazh INVENTORS TH El R ATTORNEYS Patented June 21, 1938 UNITED STATES PATENT OFFICE MEANS FOR ADJUSTING THE ELECTRODES OF ELECTRIC FURNACES Application July 16, 1937, Serial No. 154,019 In Germany December 20, 1934 9 Claims.

The present invention relates to means for adjusting the electrodes of electric furnaces.

The electrodes of electric furnaces which convey electric energy to the are or the furnace bath become consumed either by burning by the are or by chemical action caused by the charge. Adjustment of an electrode towards the bath as the electrode is consumed therefore becomes necessary. This adjustment of the electrodes, however, is often very difiicult to effect, as the current is usually conveyed to the electrodes by means of contact members which are pressed against the electrodes by the aid of screws, springs or by means of pneumatic or hydraulic pressure and which in most cases must simultaneously grip and carry the electrodes. In such cases it is difficult to ensure that the current is uninterrupted or undesirably varied while the electrode position is being adjusted.

For modern large industrial furnaces electrodes weighing 20,000 kilograms and more and carrying a current of 200,000 amperes and more are used. These large electrodes are often secured by contact plates with the aid of clamping or supporting rings which are movably arranged directly above the furnace charge; these clamping or supporting rings, therefore, are subjected to large strains. The heat of the furnace, mechanical wear and tear and scraping or electric currents in the members, however, produce structural defects which cannot 'be avoided and often cause an interruption of supply.

To change the contact plates which after a certain period become destroyed and also to change the clamping rings themselves is a rather difficult operation and requires very skilled workmen who are often forced to work above the still glowing furnace charge so that the work is very arduous.

Besides these difficulties there exist those drawbacks which are caused by interruption of the furnace working, such as a decrease of production, undesired cooling of the furnace hearth and the charge and the strains produced in the structural parts of the furnace.

In order to connect the current supply network with the electrode or with the clamping plates of the electrodes furnaces were hitherto usually provided with a flexible conductor which followed the movement of the electrode) and which consisted, for instance, of flexible tubes, cables or strips. These flexible conductors are often subjected to a high furnace temperature and are thereby exposed to great wear and tear so that they must often be changed.

Now we have found a device which fulfils the functions of the devices hitherto employed for carrying the electrode, moving the latter and conducting the current. The device comprises one or more bands or chains movable in a direction parallel to the axis of the electrode and located at the side of the electrode at a determined height by guiding means, clamping contact plates for gripping the electrode being arranged on the band or chain in such a manner that they are pressed strongly against the electrode where the band or chain is guided at said fixed height along the electrode so that the electrode is held in any desired position while it is maintained electrically connected to the supply network and means located nearlyat the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against the electrode being pressed from the other side by the clamping contact plates.

The chain or band provides the means for raising and lowering the electrode whereas the contact plates arranged thereon serve for the transmission of pressure and current to the electrode.

If only one band or chain is arranged at one side of the electrode, the electrode must be guided by stationary rollers at the opposite side which exert a counterpressure against the electrode. If several bands or chains are used, they are preferably angularly equally spaced around the electrode and bear upon it. In this case each of the chains exerts a counterpressure against the pressure exerted by other chains around the electrode. It is especially advisable to arrange each of the chains carrying the clamping contact plates as an endless track. The current may be conducted to the electrode in the device according to the invention in such a manner that only the part of the endless track guided at the side of i. e. facing, the electrode acts as a conductor, while the part on the opposite side or run is not in the circuit. This arrangement has the special advantage that clamping contact plates which may be damaged can be changed and replaced by new plates without having to interrupt the current supply and therefore the working of the furnace.

If the bands or chains are arranged as endless tracks the electrodes may for instance be supported in such a manner that pressing means act upon the part of the track facing the electrode which means at this part of the track press the clamping contact plates against the electrode whereas the plates on the opposite side of the track need not be so pressed. It is especially advantageous to press all the clamping contact plates against the electrode by means of a common pressure transmitting member. This arrangement has the advantage that the pressure is uniformly distributed over all the contact plates, so that the electrode is guided precisely and, when a so-called plastic electrode is used, is not deformed by constriction. In the same manner the pressure may be transmitted to the clamping contact plates supporting the electrode when the band or chain is not endless.

The accompanying drawing diagrammatically illustrates an embodiment of the invention in which an electrode is guided by four endless tracks formed by open link chains each provided with clamping contact plates.

In the drawing Fig. 1 is a side elevation of such a track and illustrates the mode of operation thereof.

Fig. 2 is a horizontal cross section through the device.

Referring to the drawing, clamping contact plates 1 and rollers 3 are arranged on the endless open link chain I forming an endless track. This track is guided over stationary drums 2, one or more of which are arranged to drive the track. In order, where a number of tracks are employed, to cause them to run in synchronism, the driving drums may be driven by toothed gearing or by any other known arrangement for producing constant speed. The clamping contact plates 1 with the rollers 3 at the part of the track facing the electrode 6 are pressed towards the electrode 6 by clamping springs 4 which thrust on a rail 5 and the plates serve simultaneously as supporting and current transmitting means, the rail 5 serving as part of the circuit of the plates and electrode. The pressure of all the plates 1 supports the electrode which is raised or lowered as the track is moved. Anchor rings l0 are provided to take up the back thrusts and to serve as fixed supports.

The height of the electrode may be adjusted and regulated by means of a motor controlled in dependence on the intensity of the current of the r furnace, the motor being coupled with one or more of the drums 2. For example, if the current exceeds a permissible maximum value or falls below a minimum value the chain is driven by the motor so that the track moves the electrode up or downward until the current has reached its normal value.

The contact plates may be changed without interrupting the furnace operation; the substi tution of the plates is effected in the run 8 which is remote from the run which presses on the electrode and this can be done by removing the bearing caps 9 of the chain pins.

The entire arrangement may be suspended or supported from below.

Instead of four driving tracks illustrated in the drawing, 2, 3 or 5 tracks may, of course, be arranged, equally angularly spaced around the electrode. It is also possible to use only one chain, for instance that illustrated on the lefthand side of Fig. l of the drawing. In this modification a number of small rollers may be arranged on the right-hand side of the electrode shown in Fig. 1 to guide the electrode on this side. If the chain I is not formed as an endless track the ends must, of course, be secured in a suitable manner. For example, they may be wound on drums or attached to springs which can be loaded or unloaded in order to move the chain by means of, for example, a system of levers and so adjust the position of the electrode.

In all these cases, however, the chain serves to raise and lower the electrode While the necessary pressure to hold the electrode is only transmitted to a short part of the chain immediately facing the electrode.

We claim:

1. Means for adjusting the electrodes of electric furnaces which comprises at least one chain movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the side of the electrode at a determined constant height, clamping contact plates carried by the chain, means for strongly pressing said plates against the electrode Where the chain is guided at said fixed height along the electrode, and means located nearly at the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against the electrode being pressed from the other side by the clamping contact plates so that the electrode is held in any desired position While it is maintained electrically connected to the supply network.

2. Means for adjusting the electrodes of electric furnaces which comprises a chain movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the side of the electrode at a determined constant height, clamping contact plates carried by the chain, means for strongly pressing said plates against the electrode where the chain is guided at said fixed height along the electrode, said chain with the clamping contact plates being arranged at one side of the electrode, and a number of stationary rollers located nearly at the same height as the guided part of the chain at the opposite side of the electrode and exerting a counterpressure against the electrode to thereby guide it on that side.

3. Means for adjusting the electrodes of electric furnaces which comprises a number of chains movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the sides of the electrode at a determined constant height, said chains being nearly angularly equally spaced around the electrode whereby each exerts a counterpressure against the pressure exerted by other chains around the electrode, clamping contact plates carried by the chains, means for strongly pressing said plates against the electrode where the chains are guided at said fixed height along the electrode, so that the electrode is held in any desired position while it is maintained electrically connected to the supply network.

4. Means for adjusting the electrodes of electric furnaces which comprises at least one endless chain movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the side of the electrode at a determined constant height, clamping contact plates carried by the endless chain, means for strongly pressing said plates against the electrode where the endless chain is guided at said fixed height along the electrode and means located nearly at the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against the electrode being pressed from the other side by the clamping contact plates so that the electrode is held in any desired position while it is maintained electrically connected to the supply network.

5. Means for adjusting the electrodes of electric furnaces which comprises at least one chain movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the side of the electrode at a determined constant height, clamping contact plates carried by the chain, means for strongly pressing said plates against the electrode Where the chain is guided at said fixed height along the electrode, of which clamping contact plates only those guided at the side of the electrode act as conductors for the electrical connection to the supply network while the plates on the opposite side are not in the circuit and means located nearly at the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against the electrode being pressed from the other side by the clamping contact plates.

6. Means for adjusting the electrodes of electric furnaces which comprises at least one chain movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the side of the electrode at a determined constant height, clamping contact plates carried by the chain, pressing means acting upon those clamping contact plates facing the electrode which pressing means at this part of the chain press the contact plates against the electrode and means located nearly at the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against the electrode being pressed from the other side by the clamping contact plates so that the electrode is held in any electrode member and means located nearly at the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against the electrode being pressed from the other side by the clamping contact plates so that the electrode is held in any desired position while it is maintained electrically connected to the supply network.

8. Means for adjusting the electrodes of electric furnaces which comprises at least one chain movable substantially in a direction parallel to the axis of the electrode, guiding means adapted to maintain the chain at the side of the electrode at a determined constant height, clamping contact plates carried by the chain, pressing means acting upon those clamping contact plates facing the electrode to strongly press said plates against the electrode where the chain is guided at said fixed height along the electrode, said plates acting as conductors for the electrical connection to the supply network while the plates on the opposite side of the chains can be changed during the working of the furnace, and means located nearly at the same height as the guided part of the chain and nearly at opposite sides of the electrode which means exert a counterpressure against theelectrode being pressed from the other side by the clamping contact plates.

9. Means for adjusting the electrodes in electric arc furnaces comprising at least one chain having a run thereof movable in a direction substantially parallel to the major axis of the electrode, guiding means for the chain adapted to maintain said run of the chain at the side of the electrode at a predetermined constant height along the said side of the electrode, clamping contact plates carried by the chain, means for forcing said plates into gripping and electrical contact with said side of the electrode and means operating on the opposite side of the electrode in opposition to the force set up by said clamping plates so that the electrode is held in any desired position while being maintained in electrical connection with the current supply.

ERNST W INTER. FRANZ LUCKERATH.

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