GB704713A - An electric smelter for producing porcelain enamel frit - Google Patents

Abstract

704,713. Electrode furnace for porcelain enamel. THORNTON, A. A. (Ferro Enamel Corporation). Feb. 6, 1952, No. 3137/52. Class 39 (3) A smelter for porcelain enamel frit in which the constituents are heated bv current therethrough comprises a refractory-lined rectangular vault having its bottom 9 stepped down longitudinally from an end wall 4 to a low rectangular communication passage 11, where the molten enamel passes from the melting chamber under a vertical wall 5 into a lining chamber 19, whence the enamel frit passes over a weir 28 in the end wall to pass through a vertical discharge opening 30. The charging opening 18 in the end wall 4, the passage 11 and the discharge weir 28 are axially aligned along the line of flow of material. Pairs of electrodes are arranged on opposite sides of the axial line, the first pair A being adjacent the charging opening 18, the second pair B arranged downstream therefrom and more widely spaced in the melting chamber. A third pair of electrodes C is arranged further downstream and adjacent the passage 11 and a fourth pair of electrodes D is arranged adjacent the weir 28. The furnace is roofed and the partition wall 5 has an upper aperture 42 through which hot gas passes from the fining chamber to the melting chamber, whence it is discharged through a roof chimney 17, preferably under reduced pressure. The electrodes A, B for melting are of material lower in the electromotive series than the materials present in the batch as oxides. Thus in the presence of zirconium oxide, the electrodes are of molybdenum, but with the oxides of cobalt or nickel, graphite electrodes may be used. Inclined molybdenum plate electrodes A, B are supported by brackets 33 on rods 31 passing through the furnace walls. The rods 31 are carried externally by an angular bracket 35 pivoted at 37 on a bracket 38 on the wall, so that the transverse distance between the electrodes may be adjusted. The lower edges of door openings 39 have recesses in which a block is placed over the rod, allowing vertical adjustment of the electrodes A, B. The smelter may be emptied through a discharge in the side wall below the bridge 5. Specification 683,701 is referred to.