GB927871A - Improvements in and relating to the mounting of electrodes of electric furnaces - Google Patents

Abstract

927,871. Furnace electrode holders. SPEMBLY Ltd., and A. C. THORNE. Aug. 1, 1961 [May 6, 1960], No. 16130/60. Class 39 (3). A mounting for a rod electrode of an electric furnace comprises two cooling jackets rigidly secured together and electrically insulated from one another, one cooling jacket serving to support the electrode, and the other cooling jacket being secured to the furnace casing and surrounding a portion of the electrode in spaced relationship. In the example shown, a graphite electrode 12 has a tapered portion 18 engaging a lower water jacket 2 which is attached to an upper water jacket 1 by studs 13 and nuts 13A. The jacket 1 is spaced from the electrode as shown, and is secured to a housing 15 by studs and nuts 14, the housing being welded to a bottom wall 28<SP>1</SP> of a furnace casing (Fig. 3). The jackets are electrically insulated from one another by joint rings 3, 4. Cooling water for the jackets is circulated through inlets 20 and outlets 21, partitions 17 being included in the jackets to direct the water upwardly and then downwardly. The electrode is secured in the jacket 2 by a screw-threaded ring 10 and its tapered portion 18 may be copper plated to improve its electrical contact with the jacket. A central axial bore is provided in the electrode whereby the temperature of the electrode can be determined with the aid of an optical or radiation pyrometer head 5. Electrical connections are made to the jacket 2 by means of axial bores (Fig. 2, not shown) in the end of the jacket in which cable ends are secured. A vacuum-tight joint ring 19 is provided between the housing 15 and the jacket 1, and a joint ring 29 is provided between the housing 15 and a section c of a graphite sleeve which engages the jacket 1; the ring 29 also seals a thin metal lining 27, the space between which and the furnace casing 28 is filled with refractory material e.g. lampblack. Sections a, b, c of the graphite sleeve shrouding the electrode are connected by joints as shown, the upper section a engaging an aperture 24 in a graphite hearth-plate 23. The joints in the graphite sleeve are adapted to allow the section b to pivot in a vertical plane to compensate for radial expansion of the furnace. The upper end of the electrode is of frusto-conical shape, and engages a corresponding recess in a graphite ring (not shown) forming part of a heating element and with which other electrodes similar to that shown are also engaged. Each water jacket may comprise an inner and an outer shell welded together at the points shown; and each shell may be made from mild steel. Specification 922,891 is referred to.