US1538286A

US1538286A - Protecting device for the cooling cylinders of the electrodes of furnaces heated by arcs

Info

Publication number: US1538286A
Application number: US707252A
Authority: US
Inventors: Krause Edmund
Original assignee: Individual
Current assignee: Individual
Priority date: 1924-04-17
Filing date: 1924-04-17
Publication date: 1925-05-19
Anticipated expiration: 1942-05-19

Description

May 19, 1925. 1,538,286

E. KRAUSE PROTECTING DEVICE FOR THE COOLING CYLINDERS OF THE ELECTRODES 0F FURNACES HEATED BY ARCS Filed April 17, 1924 mii I f /r of fine/war; 6-Ml 131 Y Patented May 19, 1925.

UNITED STATES PATENT. OFFICE.

EDMUND KRAUSE, OF HENNIGSDORF, NEAR- BERLIN, GERMANY.

PROTECTING DEVICE FOR- THE COOLING CYLINDERS THE ELECTRODES OF FUR- NACES HEATED BY- ARCS.

Application filed April 17, 1924. Serial No. 707,252.

T 0 all whomit may concern:

Be it known that I, EDMUND KRAUsE, a citizen of the German Republic, residing at Hennigsdorf, (Osthavelland), near Berlin, Germany, have invented a certain new and useful Protecting Device for the Cooling Cylinders of the Electrodes of Furnaces Heated by Arcs, of which the following is a s ecification.

n electric furnaces heated by arcs, either the electrodes electrically insulated, 'are passed through the cooling cylinders or rings in which case the cooling rings are connected to the furnace body by a metallic and electrically conducting connection, or the electrodes are passed through the cooling cylinders or rings without insulation, in which case the cooling rings are electrically insulated from the body of the furnace.

In both cases there is frequently notice able the disadvantage that when an-electrode breaks the are which is produced at the point of fracture perforates the cooling ring or cylinder surrounding the electrode so that the cooling water flows into the furnace thus causing interruption in the operation of the furnace for long periods, and involving expensive repairs.

To meet this disadvantage there is provided, according to the invention, a protecting device the purpose of which is to insulate electrically the electrodes from the cooling cylinders or rin s and also the cooling cylinders or rings from the furnacebody. By such double insulation it is possible for the cooling cylinders or rings to be connected so. that there is an electrically conducting path, to the furnace transformer or the cur rent generator by the switching-in of relays or maximumcurrent cut-outs, with or without the interposition of resistances.

By means of this protecting device, the slightest contact of the arc with the cooling cylinder immediately opens the main switch of the furnace transformer or current generator, and it is prevented from being closed during such time as the broken electrode is being replaced by a new one.

The device according to the invention is diagrammatically illustrated, by way of example, in the accompanying drawing.

The electrode a, which is connected to phase I of the transformer b, is insulated electrically both from the cooling cylinder 0 and from the furnace cover (I by means of the insulating material 6. The cooling cylinder 0 is connected by an electrical conductor f, through the series resistance 9 and a relay or maximum current cut-out h, to the zero point i of the transformer. Instead of the conductor f being connected to the zero point 2' of the transformer b, it may be connected upto one or other of phases II and III, in which case the conductor is completed through the transformer.

, If the electrode a becomes broken, the are produced contacts with the cooling cylinder 0' thus producing a closed circuit from the electrode a through the cooling cylinder 0, the resistance 9 and the relay h, to the furnace transformer b or current generator. By this means the relay is actuated and instantly closes the cut-out current I: of the main switch Z and simultaneously locks the switching-in current to the long distance connection of the main switch Z. The relay h is provided with a mechanical locking device m, which looks the relay after its operation until the mechanical lock is released by hand. By the use of this mechanical locking mechanism and by numbering the relays to correspond to the electrodes it is at once pos-. sible to determine where the broken electrode is situated.

Instead of actuating the protecting device by the furnace transformer, a special or secondary source of current. may be provided which supplies the current for actuating the switching-out relay upon an electrode being broken.

I claim: p

1. A protecting device for the cooling cylinder of the electrodes of furnaces heated by arcs, characterized in that not only are the electrodes insulated from the cooling cylinders or rings, but the cooling cylinders or rings are themselves insulated from the bodyof the furnace and are connected by an electrically conducting path to the furnace transformer or current generator, a switch device, which becomes effective in case of an electrode breaking, being interposed.

2. A protecting device according to claim 1, characterized in that a relay or maximum current cut-out is provided in the electrically conducting path between the cooling cylinders or rings and the furnace transformer, with or without the interposition of resistances, which cuts out the furnace when an ductor with relay,

electrode breaks and thereby prevent the cooling cylinders or rings from being fused. 3. A protecting device according to claim 1, cha acterized in that the relay or maximum current cut-out connected up into the protecting conductor is provided with a locking or stop device by which the oven is prevented from being rendered operative when an electrode has broken.

4. A protecting device according to claim 1, characterized in that for each electrode there is provided a separate protecting conlocking devices or stops and the like, whereby, by means of an indicating device, an indication is given that an electrode is broken and consequently an arc EDMUND KRAUSE.