US2686961A - Method of constructing turning tables for electric furnaces - Google Patents

Description

24, 195.4 T. ELLEFSEN 2,686,961

METHOD OF CONSTRUCTING TURNING TABLES FOR ELECTRIC FURNACES Filed Feb. 8, 1952 2 Sheets-Sheet 1 INVENTOR. Ybrmzs [tie/sew ATTORNEYS Aug. 24, 1954 T. ELLEFSEN METHOD OF CONSTRUCTING TURNING TABLES FOR ELECTRIC FURNACES Filed Feb. 8, 1952 2 Sheets-Sheet 2 Patented Aug. 24, 1954 METHOD OF CONSTRUCTING TURNING TABLES FOR ELECTRIC FURNACES Tonnes Ellefsen, Porsgrunn, Norway, assignor to Elektrokemisk A/S', a corporation of Norway Application February 8, 1952, Serial No. 270,730

3 Claims.

In United States Patent No. 2,300,355, dated October 27, 1942, I have described an electric furnace in which relative movement between the electrodes and the charge is preferably obtained by maintaining the electrode stationary and rotating the body of the furnace. The present invention relates to a method of constructing such furnaces whereby they may be operated efficiently with a relatively small expenditure of power.

As shown in my earlier patent the furnace body is mounted on wheels positioned toward the circumference of the furnace, which wheels run on a track. Experience has shown that it is exceedingly diflicult to arrange these wheels so that they carry a uniform load. As a result, certain of the wheels have carried the major portion of the load and the friction on these wheels has been so great that undue power consumption has been used to maintain the furnace in rotation. It will be realized that this problem is a serious one when it is borne in mind that the furnace to be rotated may weigh from 200 tons to 500 tons.

In accordance with the present invention I build such a furnace as follows:

First of all, a proper foundation is laid and on this is built a track which is as level as possible.

This track is then machined for accuracy, preferably by a rotary cutter pivoted at its center. A central plate or member is then provided and radial arms run out from this central plate to which are attached the wheels that run on the track. These radial arms are of substantial strength but are of sufficient flexibility relative to the central member so that the wheels will all rest evenly on the track during the time that the concrete is being poured and hardened.

The actual shaping of the concrete mass is accomplished by providing forms supported from below onto which the concrete is poured. These forms support the central member to which the arms running out to the wheels are attached and these forms should be so arranged that the concrete can embed the attachments to the wheels without imposing any material weight on the wheels before the concrete has hardened. Since the wheels will be resting on the track throughout the whole period while the concrete is being poured, it will be found that when the concrete has hardened and the forms are removed, the weight of the concrete support bed is evenly distributed between the wheels.

I find it preferable to provide the central plate with a thrust member and to provide a corresponding thrust member on the foundation immediately below. By having these two members spaced apart slightly, friction at this point will be avoided but nevertheless the supports will be present as an emergency bearing in case anything should happen to the wheels. If desired there may even be some contact and a small part of the load may be carried on this central support but this ordinarily is not advisable, as it is preferred that after the support table is cast and has become rigid, the entire weight should be carried on the wheels and be distributed equally between them.

When the support table has hardened and is fully rigid, the actual furnace is erected on this table and preferably is carried on columns each of which is positioned at a point on the support table directly over one of the rotating wheels. By this arrangement the furnace can be rotated with a remarkably low expenditure of power.

This invention can readily be understood by reference to the accompanying drawings which illustrate the production of a. furnace made in accordance with my invention. In these drawings Fig. 1 shows a vertical section through a furnace embodying my invention; Fig. 2 shows a plan view of the furnace of Fig. 1 with parts broken away and Fig. 3 shows a sectional view with the wheels and forms for pouring the concrete support in place and the concrete mass of the support table indicated.

In these drawings, [9 is the foundation for the furnace which must be very solidly built so that it will remain fixed. On this furnace is mounted the track I 2 the top of which is machined to make it smooth and absolutely level. In the middle, the foundation carries an upward extension I4 on which is positioned a support member [6 which may be of metal. Another support member l3 preferably also of metal is positioned above the support It. Each of these supports is preferably provided with a central opening and through them runs a central shaft 20 which may be fixed in the support It; and rotate freely in support [8 or vice versa. The support member I S and shaft 20 may be used as a central tap for grinding the track 12. Shaft 20 preferably is made hollow and may be employed for running pipes for cooling water and the like to the furnace.

The manner in which the support table for the furnace is poured or cast is indicated in Fig. 3. As shown in this figure, temporary forms are provided braced from below on the foundation In. In the particular embodiment here illustrated these forms are shown as made up of radial timbers 22 carried by vertical struts 24. Short struts 26 support the inner ends of the beams 22 and if desired the beams 22 can have their inner ends running beneath the upper flange of support member [8.

A series of wheels 28 rest on the track [2 and are connected with the support member 18 by the central plate or member 30 and the flexible metallic arms 32. The arms 32 are connected to the hub mounts 3 in which the hubs of the wheels 23 rotate. A flooring 36 is built on the beams 22 to support the concrete table while it is hardening and the hub mounts 34 of the wheels are free to move vertically relative to this flooring sufliciently so that the wheels 28 rest on the track 12 without carrying any appreciable part of the weight of the structure which is to support the concrete bed of the furnace. In the embodiment shown, the arms 32 are shown as interconnected by circular plates 38, 40 and 42, and extending upwardly from these plates and also from plate 30, are bolts 44 carrying crossbars 45 which will be firmly embedded in the final concrete. In addition to the flooring 3b the form includes side walls 48 also supported from the beams 22.

When thi framework is erected as indicated in Fig. 3, it is to be noted that each wheel rests evenly on the track l2 and since the arms 32 are flexible, there is no substantial pressure on these wheels to bring them out of adjustment.

A concrete slab is now poured on the platform 1 36 and within the side walls 43. The top shape of this slab is indicated in dot and dash lines in Fig. 3. This concrete slab will be entirely supported by the beams 22 and the struts which hold these beams up, and virtually none of the weight of the concrete will be transmitted to thewheels 20 which will still stay evenly pressed on the track l2.

Ultimately when the concrete has thoroughly set, the strutsZt and 2t and beams 22 and the forms supported by these beams will be removed. Now the weight of the slab will be carried by the wheels 28but since these wheels were at all times pressing'evenly on the track 82, they will continue to do so and thus an even distribution of weight on the wheels is attained.

Subsequently, the columns 52 of brickwork or the like are built on the concrete mass 59 and preferably these columns are positioned over each wheel 28. Onthese columns is positioned the main furnace 54. The numeral 56 indicates the electrodes which extend down into the furnace chamber but are held stationary as explained in my earlier'patent.

The furnace can be rotated by means of an electric'motor 58 operating through a gear train on the internal gear 68 which is attached to the arms 32 by means of projections on bolts Mi.

It is to be borne in mind that the furnace rotates very slowly. For example, it may make approximately one rotation in 24 hours. By distributing the weight evenly between the wheels 23 asdescribed I have found it possible to drive afurnace weighing 2000 tons with a motor of from to /2-horsepower.

It may also be noted that a wall 62 is supplied outside the wheels 28 and the track l2. This should be of suflicient strength to carry the support table and protect the machinery against damage in the event of wheel breakage. Also it will protect the rotating mechanism in case any of the contents ofthe furnace should spill over.

It is understod that the foregoing specific example is given only for the purpose of illustration,

This application is a continuation-in-part oil my earlier application Serial No. 729,961, filed February 20, 1947, now abandoned. i

What I claim is:

1. The method of constructing a rotatable furnace of great weight which comprises forming a level circular track, positioning on the track on a fixed solidly built foundation a series of spaced wheels each provided with a hub having an upwardly extending mount, interconnecting such hub mounts by a-metallic support structure sufficiently flexible so that the wheels will rest evenly on the track, providing a formsupported independently of the wheel hubs and their mounts below and around such metallic support structure but above said wheels into which concrete can be poured, pouring concrete into such form while the wheels are resting evenly on the track to form a concrete slab in which the metallic support structure connecting the hub mounts is embedded, permitting such concrete slab to harden whereby the hub mounts of the wheels are permanently locked in relative vertical position so that the wheels will be free to rotate but will bear equally on the track, removing the forms on which the concrete structure is cast so that the weight of the slab is carried on the wheels and constructing a furnace on such slab.

2. A method as specified in claim 1 in which the form for the concrete slab is adapted to support the central portion of such metallic support structure while the hub mounts oi the wheels are free to move vertically relative to such form sufficiently so that the wheels rest on the track without carrying any appreciable partof the weight of such form.

3. A method as specified in claim 1 which further includes the step of attaching to said metallic support structure, after the concrete slab in which it is embedded has hardened, a driving mechanism whereby said slab may be rotated.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,309,384 Yeomans July 8, 1919 FOREIGN PATENTS Number Country Date 921,027 France Jan. 8, 1947

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