US2200372A - Electric steel furnace or the like - Google Patents

Description

May 14, 1940. w. LINDER ELECTRIC STEEL FURNACE OR THE LIKE Filed May 11, 1938- 2 Sheets-Sheet 1 Jr; ve nfor:

May 14, 1940. w. LINDER ELECTRIC STEEL FURNACE OR THE LIKE Filed May 11, 1938 2 Sheets-Sheet 2 Jnvenfo/z- Patented May 14, 1940 PATENT OFFICE ELECTRIC STEEL FURNACE OR THE LIKE Willy Linder, Essen, Germany, assignor, by mesne assignments, to Koppers Company, Pittsburgh, Pa., a corporation of Delaware Application May 11, 1938, Serial No. 207,295 In Germany May 12, 1937 6 Claims.

The present invention relates to electric steel furnaces and other furnaces with a roof of refractory material supported. by a frame independently of the anchorage of the side walls of the furnace, and more particularly to those electric steel furnaces or the like in which a removable coverconsisting of refractory material is provided upon the furnace, said cover being constructed like an arch and arranged within a ring- .10 shaped frame.

The arched roof of the electric steel furnaces known hitherto is supported by a rigid frame. The refractory bricks of the arched roof, however, expand to quite a considerable extent when the temperature of the furnace is raised to the very high operating temperature necessary for the production of steel or other materials. Since the frame of the roof as provided in the known steel furnaces cannot expand or give way in radial direction, the heat expansion of the roof bricks will force the material inwardly and this will cause a raising-upwards of the arch towards the centre thereof. If the refractory material of the furnace roof expands in this way, then the roof bricks no longer touch one another along their whole side faces, but only with their inner edges or with small zones adjacent thereto. Consequently, certain points of the individual brick are highly stressed and the inner edges of the 80 bricks tend to crack or spell-off. The life of the arched roof of the known electric steel furnaces is therefore comparatively short.

The main object of my present invention is to provide such improvements in electric steel furnaces Or other furnaces fitted with an arched roof that is anchored independently of the furnace side walls, which will allow a heat expansion of the refractory material of the furnace roof without exerting any dangerous additional 40 stresses upon the roof bricks.

My present invention principally consists in holding the refractory brickwork of the roof of electric steel furnaces or the like together at the circumferenceof the roof by elastic means, which 5 are fixed to a rigid ring-shaped supporting frame,

and against the pressure of springs arranged between the rigid frame and the said elastic supporting elements.

Another important feature of my invention in- 59 eludes the novel arrangement of the bricks in the bricklining of the roof of furnaces, and final ly my invention also comprehends the provision of means which enable the exact adjustment of the posltion of the elastic supporting elements relatively to the rigid supporting frame, and

limit the movement of the said supporting elements.

With the above and other objects and features of my present invention in view, I will now describe a preferred embodiment of my invention 6 on the lines of the accompanying drawings, in which Figure 1 shows a vertical section through the roof of the electric steel furnace built according to my present invention said view being taken 10 in part on the line A-A and in part on the line' BB.

Figure 2 is a side elevational view of the lateral framing of the roof on an enlarged scale.

Figure 3 is a view from below the roof accord- 1 ing to Figure 1.

The reaction or melting chamber of an electric steel furnace, only partly shown on the drawings, has been marked in the figure with l the furnace comprises the refractory brickwork 2 and the steel shell 3, enclosing the brickwork. The furnace chamber is closed at the top by means of the removable arch 4 which is traversed by the electrodes 5. The arched roof is covered on the outside by an insulating layer 6.

The arch is held by a tension frame consisting of a multitude of adjoining segment-like brick clamp supports 1 which are conformed to a circle in the design of the arch illustrated on the drawings.

The brick clamp supports 1 are suspended in a closed ring-shaped frame I by the means of the carrying levers I3 and fulcrum levers 9. The suspension, in the mode exemplifying this kind of construction, is effected in such a manner that $5 thefulcrum levers 9 engage in grooves suitably arranged on the circumference of the frame 8 by means of bushes It so that the clamp supports I may move about these points as pivots. The supporting frame I is further fitted with bearings H which are traversed, for a greater play, by the tension bolts II, which tie the carrying levers l3 of the supports 1 with the carrying frame 8, the bolts, at a certain distance behind the bearing, carrying the pressure-springs H, the tension of which is adjusted by screw-nuts II. Figure 1 of the drawings indicates the arch in cold condition. In this state, the carrying lever 13 fits directly against the supporting frame bearing II. In working condition, the pressure spring I4 is compressed by the degree of expansion so that the brick clamp supports I, together with the carrying levers l3 and fulcrum levers 9 assume the position indicated at A in dash and dot lines on the drawings, when the fulcrum -cold layers of the levers l3 together with the screw bolts l2 adjust themselves in corresponding to the movement about the turning point Ill.

Each brick clamp support I is fitted with at least one fulcrum lever 9 suspended from the fulcrum point It, and furthermore with two or several pressure-members l2, [4 supported by the supporting frame 8. In order to avoid a too considerable displacement of the roof bricks, and thus a loosening of same, in case of failure of the pressure screws l4, or relaxing of the tension, the fulcrum levers 9 and supporting frames 8 are also connected together by set screws IS, the nuts I! of which are adjusted in such a manner that they form a limitation for the greatest possible expansion of the arch in which the bricks still fit tightly against one another.

The supports 1 are fitted below with a flange 18 to which is affixed a vertical sheet-iron sealing frame 19 lying in a sand seal 20 so that a gas-tight closure for the furnace is ensured. In order to avoid a cooling-down of the interior of the furnace at the bearing face of the clamp supports 1, a refractory packing mass 2| is provided between the brickwork 2 of the substructure and the arch 4 of the electric steel furnace.

The arch 4 is suspended from a supporting frame 23, through the suspension frame 8, by means of eye-hooks 22 aflixed to same. The eyehooks 22 are for this purpose connected with pulling devices 24 which run over the rollers 25 on the supporting frame 23 and which are operated by a driving shaft, not shown on the drawmgs.

The process of pouring-out the melting bath is preferably carried out in such manner that the arched cover is removed from the furnace, the furnace is moved to the side and then tilted. After the discharge, the furnace is suitably topcharged during the run, the furnace is driven-in again and the cover placed on. In this way, an appreciable cooling down of the furnace as well as of the arch is avoided.

It must be mentioned that levers or the like capable of being put under pressure may be used instead of the pressure springs l4.

The efficiency of the furnace roof designed in accordance with the before mentioned description will also be considerably improved if the bricks of the arched cover-in the outer layers adjoining the supports 1 are not laid in a continuous bond, but if they form segments of brickwork laid in a bond which correspond to the length of the individual supports 1, while the roof bricklining towardsthe centre is carried out as usual in a continuous bond.

This is of advantage since the movable supports can be pressedJoack again corresponding to the heat expansion of the bricks, without necessitating provision of means for supplying an additional pressure for overcoming the friction of the roof bricks, due to the interconnection of the roof bricks in the outer arched cover. In case of large covers, the friction of the roof bricks in the outer layers, if the arched-roof is constructed in a continuous bond, may under certain conditions be to such a considerable degree that the movable arrangement of the roof supports is thus rendered ineffective.

Figure 3 of the drawings clearly shows the new arrangement of theroof brickwork. The mode of carrying out the invention according to Figure 3 corresponds to the arrangement of Figures 1 and 2 as regards the roof construction in general. The outer layers 32 of the roof brick-lining adjoining the segment-like supports 3| are laid in a bond in segments as may be seen from Figure 2. The various groups or segments thus formed are separated from one another by continuous joints 33. The internal sections of the roof arch 34 are, however, laid in a continuous bond.

The insulating layer placed above the roof, is likewise suitably carried out in a continuous bond. This layer generally consists of light bricks which are able to follow easily the movement of the roof supports. Should it happen, that the joints 33 gape during the operation, a sufficient seal is easily obtained by the insulating layer, situated above the roof, as shown in Figure 1.

Various changes may be made in the details of the construction of the foregoing specification, without departing from the invention and the advantages thereof, since the invention is not limited in all its aspects to the mode of carrying it out as described and shown, but may be variously embodied within the scope of the following claims.

I claim:

1. Metallurgical furnace or the like with the arched roof of the furnace supported independently of the side walls of the furnace, comprising a rigid frame mounted so as to be lowered and lifted into and out of operative relationship. with the furnace, a multitude of segment-like supports carried by said frame, said segment-like supports surrounding the arched furnace roof consisting of refractory bricks and clampingly supporting the bricks in contiguous relationship with each other, said segment-like supports being arranged moveably on said rigid frame in such a manner, that the said supports may move in a generally radial direction and means for adjusting the said segment-like supports, the rigid frame being spaced from the arch roof so as to be entirely clear of the same, the bricks of the roof being free of support by suspensory means between its margins and being otherwise unsupported other than by the segment-like supports that surround the arched roof, and the spaced rigid frame and segment like supports for clamping the bricks also constituting the sole load carrying and supporting means for the arched roof and its bricks.

2. Metallurgical furnace or the like with the arched roof of the furnace supported independently of the side walls of the furnace, comprising a rigid frame mounted so as to be lowered and lifted into and out of operative relationship with the furnace, a multitude of segment-like supports carried by said frame, said segment-like supports surrounding the arched furnace roof consisting of refractory bricks and clampingly supporting the bricks in contiguous relationship with each other, said segment-like supports being arranged moveably on said rigid frame in such a manner, that the said supports may move in radial direction, spring means arranged between said rigid frame and said segment-like supports so as to draw the latter to the former in such manner that the said segment-like supports are forced towards the center of the arched roof, the rigid frame being spaced from the arch roof so as to be entirely clear of the same, the bricks of the roof being free of support by suspensory means between its margins and being otherwise unsupported other than by the segment-like supports that surround the arched roof, and the spaced rigid frame and segment-like supports for clamping the bricks also constituting the sole load carrying and supporting means for the arched roof and its bricks.

3. Metallurgical furnace or the like with the arched roof of the furnace supported independently of the side walls of the furnace, comprising a rigid frame mounted so as to be lowered and lifted into and out of operative relationship with the furnace, a multitude of segment-like supports carried by said frame, said segment-like supports surrounding the arched furnace roof consisting of refractory bricks and clampingly supporting the bricks in contiguous relationship with each other, each of said segment-like supports being connected with the frame by a. lever fulcrumed on said rigid frame in such a manner that the said supports may move about the fulcrum in a generally radial direction, and means for adjusting said segment-like supports, the rigid frame being spaced from the. arch roof so as to be entirely clear of the same, the bricks of the roof being free of support by suspensory means between its margins and being otherwise unsupported other than by the segment-like sup-. ports that surround the arched roof, and the spaced frame and segment-like supports for clamping the bricks also constituting the sole load carrying and supporting means for the arched roof and its bricks.

4. Metallurgical furnace or the like with the arched roof at the furnace supported independently of the side walls of the furnace, comprisingarlgidframe molmtedsoastobelowered and lifted out of operative relationship with the furnace, a multitude of segment-like supports carried by the said frame, said segment-like surrounding the arched furnace roof of refractory bricks and clampingly the bricks in contiguous relationship with each other, each of said segment-like supports being connected with the frame by a lever fulcrmnedonsaidrigidframeinsuchamanner that the said supports may move about the fulcrumin agenenllyradialdirectiomandmeans fa: said segment-like supports, the

bearings for said levers being arranged on the outer surface of said rigid frame, the rigid frame being spaced from the arch roof so as to be entirely clear of the same, thebricks of the roof being free of support by suspensory means between its margins and being otherwise unsupported other than by the segment-like supports that surround the arched roof, and the spaced rigid frame and segment-like supports for clamping the bricks also constituting the sole load carrying and supporting means for the arched roof and its bricks.

5. In a furnace roof provided with means as set forth in claim 1, the roof bricks in the outer zones of the roof adjacent to said segment-like supports being in individual segments independent from one another and corresponding to said supports, the central part of said furnace me being arranged in a bond.

6. Electric steel furnace or the like with thearched roof of the furnace supported independently of the anchorage of the side walls of the furnace, comprising a ring-shaped rigid frame mounted so as to be lowered and lifted into and out of operative relationship with the furnace, a multitude of segment-likesupports carried by said frame, said roof consisting of refractory bricks and said segment-like supports surrounding the arched furnace roof and clampingly supporting the bricks in contiguous relationship with each 'other, said segment-like supports being arranged moveably on said ring-shaped rigid frame in such a manner, that the said supports may move in radial direction and means for adjusting the said segment-likesupports, the ring-shaped rigid frame being spaced from the arch roof so as to be entirely clear of the same, the bricks of the roof being free of support by suspensory means between its margins and being otherwise unsupported other than by the segment-like supports that surround the arched roof, and the spaced rigid frame and segment like Supports for clamping the bricks also constituting the sole load carrying and supporting means for the arched roof and its bricks.

WILLY LINDER.

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