DE1244996B - Electric furnace with furnace vessel fitted with a heating device and tiltable around an axis - Google Patents

Description

GERMAN WfiWGsSS PATENT OFFICE

EXPLAINING LETTER German class: 9 pm -18 / 30

Number: 1244 996

File number: D 38828 VIII d / 21 h

1 244 996 filing date: 3rd mail962

Opened on: July 20, 1967

The invention relates to an electric furnace, in particular an induction crucible furnace, with an axis tiltable furnace vessel provided with the heating device. Such heaters are with operated with high currents. This results in the need to generate electrical energy by means of a to transmit large numbers of power cables.

This regularly leads to difficult constructions because the high-current ropes make the pivoting movement of the furnace must compensate for the fixed power connection. To avoid a harmful self-induction, the high-current connections should be kept as short as possible. Of the Compensating for the tilting movement, however, requires longer lines. It also occurs when power lines Another difficulty in that to utilize the cross-sections under the effect of Skin effect the phases must be nested against each other.

Attempts have also been made to overcome these difficulties by using slip ring devices attached to power transmission. However, this results in considerable contact difficulties and leads to a complex construction.

The object of the invention is to provide a device for high current supply for alternating or three-phase current for such electric ovens, which avoids these disadvantages and difficulties.

In the case of roll electrode welding machines, it is known to supply the feed power to the rotating electrode disks, the primary winding of an ironless high-frequency transformer is stationary and to arrange the associated secondary winding on the rotating electrode shaft. Furthermore it is also known for rotating inductors for the heat treatment of metallic workpieces, the inductor with the drum-like secondary part of the transformer mechanically rigid connect and design the primary part as a jacket-shaped stator surrounding the secondary winding.

To solve the problem, with tiltable or swiveling electric ovens, in particular induction crucible ovens, to create a simple and reliable transmission of the electrical feed power, the application of the contactless transmission by means of the known per se is according to the invention Proposed principle of stationary primary part and axially circumferential secondary part of the transformer.

Due to the inductive transmission of the heating current, the galvanic current transfer by means of contacts or high-current ropes is avoided, and electric ovens with tiltable ones around an axis are included
the furnace vessel provided with the heating device

Applicant:

Demag Electrometallurgy G. m. B. H., Duisburg

Named as inventor:
Johannes Wagner, Bensberg

all associated disadvantages and construction costs continue.

In a preferred embodiment, the primary part of the transformer is a stationary sheath core formed with the primary winding, one leg of which is coaxial with the pivot axis and is enclosed in a ring by the secondary coil connected to the axis of movement.

Another embodiment of the invention is that the primary part of the transformer as a toroidal core with a fixed primary coil, which is fixedly attached in the radial plane coaxially to the pivot axis is formed, and the secondary part from a comprehensive cross section of the primary part, with the Pivot shaft permanently connected toroidal coil consists.

High frequency currents are used in some industrial furnaces. In these cases the invention can also be modified so that the principle of the Tesla transformer with coreless windings is applied.

Another modification of rotating furnaces is that the primary-side power supply to the transformer takes place via slip rings, the primary part of the transformer being fixedly attached in the radial plane coaxially to the axis of movement Ring coil is formed. In these cases, the use of slip rings is incompatible with the disadvantages mentioned at the outset, because there are high-voltage currents of greater amperage acts.

When applying the invention to rotating furnaces that rotate continuously, can also after a Another feature of the primary part of the transformer as being stationary and aligned coaxially to the axis of movement Transformer core be formed with the primary winding, while the secondary part a transformer core arranged concentrically to the rotating shaft and connected to it with the secondary winding, with between

709 617/416

Claims (6)

see the opposing cores a very small air gap is present, which allows the mutual relative movement. Embodiments of the invention are shown in the drawing and are described below. F i g. 1 shows the power transmission for single-phase furnace power; F i g. 2 the design according to FIG. 1 for three-phase furnace power; F i g. 3 and 4 further exemplary embodiments with an annular primary coil; F i g. 5 and 6 further exemplary embodiments with bobbins designed as a pot core. In Fig. 1 and 2, 1 denotes the furnace or some other heating vessel which can be pivoted or rotated about the axis A. With 2 and 3, the bearing points of the pivot shaft 18 are designated. The leg 4 a of the transformer core 4 lies coaxially to the movement axis A. The leg 4 a is provided with the primary winding 5. This is enclosed in a ring by the secondary coil 6, which is coaxially connected to the pivot shaft 18 by means of the holder 7. The current is supplied in a known manner to the primary coil 5 by means of the supply lines 8. The removal of the furnace current from the secondary coil 6 is not shown in particular. F i g. 2 shows the same arrangement as FIG. 1 for three-phase heating. Here, the legs 4 a, 4 b, 4 c of the three phases of the transformer are also coaxial with the pivot axis A. There are three primary coils 5 a, Sb, 5 c and three secondary coils 6a, 6 b, 6 c, the latter being provided are connected to the shaft 18 by means of a holder 7. F i g. 3 and 4 show a primary part with a toroidal core 9 and primary coil 10, which lie in a radial plane to the pivot axis A. The primary part 9, 10 is enclosed by a likewise ring-shaped secondary coil 11 which is coupled to the pivot axis A by means of a strong connection 12. Here, too, the current is supplied to the primary coil 10 by means of the supply lines 8 in a known manner, and the transformed furnace current is likewise transmitted in the usual manner from the secondary coil 11 to the heating elements. In the F i g. 5 and 6 show further modifications of the device according to the invention which can be used in continuously rotating furnaces. The furnace vessel 1 is connected to the shaft 18 and is rotatable in the axis A in bearings 2 and 3. The annular primary part of the transformer 13, 14 is fixedly attached in the radial plane and coaxially to the axilla. In Fig. 5, the primary part consists of a core with a U-shaped cross section (14) which is open towards the axis. The primary winding 13 is attached in the annular groove thus formed. A transformer core, which is also arranged within the primary part 13, 14 and has a U-shaped cross section and which contains the secondary winding 15 in its outwardly directed annular groove, serves as the secondary part. There is a small air gap between the two transformer parts, which enables the relative movement of the secondary part; this is connected to the shaft 18 by means of a holder 17. F i g. 6 shows a similar arrangement in which both the primary part and the secondary part are also formed from annular bodies. Only here are the openings of the U-shaped, but in the axial direction, profiles facing each other. Consistent with FIG. 5, the primary winding 13 and the secondary winding 15 are thus separated from one another only by a small air gap. Patent claims: 1.Electric furnace with a furnace vessel that can be tilted around an axis and is provided with the heating device, characterized by the application of the roller electrode welding machines and rotatable ones Inductors for heat treatment known per se principle of stationary primary part and axially circumferential secondary part of the transformer. 2. Electric furnace according to claim 1, characterized in that the primary part is designed as a stationary sheath core (4) with primary winding (5) , one leg (4 a) of which runs coaxially to the pivot axis (A) and from that with the pivot shaft (18) rigidly connected secondary part designed as a central coil (6) is enclosed. 3. Electric furnace according to claim 1, characterized in that the primary part of the transformer is a radial plane and coaxially to the pivot axis (A) fixedly arranged toroidal core (9) with a fixed primary coil (10) and the secondary part as a cross-section of the primary part (9 , 10) comprehensive ring coil (11) firmly connected to the pivot shaft (18) is formed. 4. Electric furnace according to claims 1 to 3, characterized in that when using High-frequency currents, the windings are designed without cores. 5. Electric furnace according to claims 1 to 3, characterized in that with continuously rotating furnace movement, the primary-side power supply to the toroidal core takes place concentrically to the movement axis (A) by means of slip rings. 6. Electric furnace according to claim 1, characterized in that with continuously rotating furnace movement, the primary part as a stationary, coaxially to the movement axis (A) arranged pot core (14) with the primary winding (13) and the secondary part as concentric to the rotating shaft (18) arranged and attached to this pot core (16) is formed with the secondary winding (15) , wherein there is a small air gap between the opposing pot cores (14, 16) which enables the relative movement. Considered publications:
German Patent Nos. 902 065, 939 465;
German Auslegeschrift No. 1102 930;
»News from Technology«, 1961, No. 4/5,
. May 1961, p. 2. For this purpose 2 sheets of drawings 709 617/416 7.67 © Bundesdruckerei Berlin