Electrode holder for electric arc furnaces

DETAILED DESCRIPTION OF THE DRAWINGS FIG.
1 is a schematic illustration of the basic structure of a combination electrode for electric arc furnaces.
This electrode comprises an electrode holder that is formed by a cooled metal shaft 1.
An active part 2 of consumable material, e.
g.
graphite, is attached by means of a threaded nipple 3 to the lower tip of the metal shaft 1 constituting the electrode holder.
The electrode is held by a supporting structure 4 affixed to the upper section of the metal shaft 1 of the electrode holder.
FIG.
1 is a schematic illustration only, the electrical components and cooling elements are not shown, as they may be of the conventional type.
The only part that is important in connection with the invention is the hollow cylindrical protective jacket 5 of temperature-resistant material which surrounds that section of the metal shaft 1 which remains within the furnace, thus protecting it from excessive thermal and mechanical stress.
The protective jacket 5 is made up of hollowed cylinder sectors 10 as shown in FIG.
2.
The hollowed cylinder sector has an inner 11 and an outer sheath area 12, two abutting surfaces in peripheral direction 13, and two faces in axial direction 14.
In addition, the sector has two bores 15 which are located on one chord.
FIGS.
3 and 4 clearly show how several sectors 10 form a partial ring by joining their abutting surfaces 13.
The sectors 10 of this partial ring are connected by springs which pass through the bores 15.
In FIG.
3 the springs shown are spiral springs 20.
Fork-like clamping elements 21 guarantee that the spiral springs 20 are secured at the end, thus prestressing them.
These elements 21 hook on counter stops located at the end of the springs 20 or on their windings, thus keeping the springs 20 in a prestressed position.
FIG.
4 illustrates on the left how the clamping elements 21 are fastened, while on the right of the illustration they are already arrested.
FIG.
5 shows how partial rings, which consist of sectors 10, are joined, thus forming a complete ring