SU857687A1 - Ore smelting furnace - Google Patents

Description

(54) ORE-THERMAL ELECTRIC OVEN

one

The invention relates to a metallurgical metallurgy industry, in particular, can be used in closed arc ore-thermal furnaces with a stationary bath, as well as in electric heating furnaces. The furnace contains a stationary, lined from the inside, rectangular-shaped bathtub cover, covered from above by a vault. The furnace arch installation unit is designed in such a way that the horizontally installed arch rests on the bath lining, and the side gap between the arch and the inner wall of the furnace casing around the perimeter is filled with electrical insulation, for example, chamotte brick or chamotte grit 1.

The disadvantage of this design is that when thermally expanding the lining c. During the operation of the furnace, there is a vertical growth of the lining of the walls, as a result of which the arch is deformed, which can lead to breakage of the electrodes, depressurization of the bath, disruption

connections of the flue duct with the vault and tubules of the feed system.

The purpose of the invention is to prevent deformation of the roof from the thermal expansion of the bath lining.

The goal is achieved by the fact that in an ore-thermal electric furnace including a roof mounted on the lining, inside the casing with a side gap around the perimeter between them, filled with electrical insulation, the inner wall of the casing in its upper part around the perimeter is provided with support brackets on which a layer of fire-resistant electrical insulation and a roof with a gap between the upper horizontal surface of the lining walls and the horizontal surface of the brackets, which is 0.02-0.04 from the height of the lining wall.

Claims (2)

In addition, a ledge of refractory material with a height equal to the height of the layer of refractory electrical insulation, mounted on brackets, with a vertical clearance relative to it and 0.3-0.5 of its height, is lined to the upper level of the walls of the lining along the perimeter. FIG. 1 shows a vertical section of the stationary bath of the furnace, general view; in fig. 2 — node I in FIG. 1. The ore-thermal electric furnace includes a bath casing 1 and a lining 2. The furnace is closed from above with a vault 3, which passes through the opening in the working ceiling of the workshop 4. The support brackets 5 are attached (welded) to the inner walls of the casing 1 in the upper part around the perimeter which is placed a layer of refractory electrical insulation 6, made for example of fireclay bricks, and its arch 3. The supporting sections of the brackets 5, on which electrical insulation 6 is laid, are set horizontally. Between the horizontal surface of the brackets 5 and the upper level 7 of the lining 2 there is a gap of 0.02-0.04 from the height of the wall of the lining 2. The side clearance around the perimeter between the roof 3 and the casing 1 is filled with electrical insulation 8. On the upper level 7 of the lining 2 laid on the perimeter of the ledge 9 of refractory material, such as fireclay bricks. The height of the ledge 9 is equal to the height of the refractory insulating layer 6. The shoulder 9 is located with a vertical clearance from the refractory power station 6. The clearance can be taken equal to 0.3-0.5 of the height of the refractory electrical insulation layer 6. With a clearance smaller than 0.3 from the height of the layer of refractory electrical insulation 6, the gap is so small that its implementation can make installation difficult. When the clearance is equal to more than 0.5 from the height of the layer of refractory electrical insulation 6, the gap is unreasonably large and impairs the thermal protection of the bracket 5. The installation unit of the roof of the stationary furnace works as follows. The load from the mass of the roof 3 through the brackets 5 is transferred to the casing 1. During operation of the furnace, the lining 2 heats up, resulting in its growth, in particular at a height. Taking into account that between the inner surface of the roof 3 and the upper level 7 of the lining 2 there is an air gap of 0.02-0.04 from the height of the wall of the lining 2, the possibility of direct contact of the surface of the lining 2 with the bottom surface of the roof 3 or bracket 5 is excluded. heating the furnace, moving its upper level 7 of the lining 2 with its vertical growth is within the limits of the air gap provided. Thus, the possibility of transfer of thermal forces arising from the vertical growth of lining 2 to the lower surface of the roof 3 and the bracket 5 is eliminated. The specified range defining the height of the air gap between the lower surface of the roof 3 and the upper level 7 of the lining 2 is equal to 0.02 -0.04 from the height of the wall of liner 2 is optimal. If the clearance is less than 0.02 from the height of the wall of the lining 2, it may turn out to be too small and with the growth of the lining 2, the upper level 7 can transmit forces to the roof 3, which makes it possible to lift the arch 3. When the clearance is more than 0 , 04 from the height of the wall of the lining 2 is a shamefully unnecessarily large in terms of thermal protection of the bracket and the casing. The size of the gap is determined analytically from the condition of the properties of the refractory material of the walls of lining 2 and its geometrical dimensions. For example, if the lining 2 is made of magnesite brick, i.e., of a material with a significant linear expansion coefficient, the gap is chosen larger than when the lining is made of light brick, which has a lower linear expansion coefficient. Practically the size of the gap can be from 50 to 100 mm. The ledge 9 reliably protects the brackets 5 from thermal radiation, since the height of the ledge 9, taken 0.02-0.04 from the height of the wall of the lining 2, ensures that its upper surface is above the brackets 5. Thus, using the invention will eliminate the mechanical effect on thermal expansion of the lining. The expected economic effect of 300 thousand rubles. in year. Claim 1. Inferno electric furnace containing arch installed on the lining inside the casing with a side gap around the perimeter between them, filled with electrical insulation, characterized in that, in order to prevent deformation of the arch from thermal lining of the bath lining, the inner wall of the casing at its top parts around the perimeter are provided with supporting brackets, on which a layer of refractory electrical insulation is installed and a roof with a gap between the upper horizontal surface of the lining walls and the horizontal surface of brackets constituting 0.02-0.04 of the height of the lining wall. 2. Electric furnace according to claim 1, characterized in that the ledge of refractory is laid on the upper level of the walls of the lining along the perimeter