CS236156B1 - Equipment for electric induction heating of metals - Google Patents

Abstract

Device for electric induction heating of metals, provided with a pan with a mechanically strong metal shell surrounded by a heating coil. The shell of the pan consists of an upper steel part (1) and a lower steel part (2), which are connected together by vertical radially oriented flat ribs (5) made of non-magnetic material. The length of the heating coil (5) is 5θ to 80% of the distance between the lower edge of the upper steel part (1) and the upper edge of the lower steel part (2). Bundles of transformer sheets (6) with pole pieces (7) are symmetrically arranged along the outer circumference of the heating coil (5), the length of the bundles of transformer sheets (6) being 50 to 100% of the distance between the lower edge of the upper steel part (1) and the upper edge of the steel part (2). The device will be used wherever metal is inductively heated.

Description

The invention relates to an apparatus for the electric induction heating of metals.

The hitherto known apparatus for induction heating of metals in a ladle simply excludes the heating of the ladle shell. This sheath must be metal and strong, because for example 40 tons of liquid steel are in the ladle. The tires are therefore made in differently divided with mutually insulated parts and mainly from expensive chrome-nickel alloys. All of this leads to the possibility of relatively small specific power inputs to the ladles or to the possibility of constructing only ladles of smaller volumes of metal.

The above-mentioned drawbacks are overcome by a device for electric induction heating of metals, provided with a ladle with a mechanically strong metal jacket surrounded by a heating coil, according to the invention. It consists in that the shell of the ladle consists of an upper steel part and a lower steel part which are connected together by vertical radially oriented flat ribs of non-magnetic material and the length of the heating coil is 30 to 80% of the distance between the lower edge of the upper steel part and the upper edge lower steel part. It is further advantageous that transformer sheet bundles with pole extensions are symmetrically arranged around the outer periphery of the heating coil, the length of the transformer sheet bundles being 50 to 100% of the distance between the lower edge of the upper steel part and the upper edge of the lower steel part.

The effect achieved by the invention is mainly that, in such a heating system, the shell of the ladle does not inductively heat up even at high specific heating powers, being mechanically very strong and consuming at least expensive materials. Also, the manufacturing effort is low and comparable to that of sheaths for normal portable metallurgical ladles.

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The invention and its effects are explained in more detail and described by way of example with reference to the accompanying drawing, in which: ο /, λ 1 shows a front view of the device in section and Fig. 2 shows section AA by this radiance m. It is transparent for electromagnetic waves, eg 50 Hz, and virtually no electrical energy is absorbed in the ladle by induction heating in a ladle. In doing so, most of the shell mass is normal structural steel, non-magnetic steel is only a part of ·

The upper steel part 1 of the ladle is of normal structural steel and has pins for catching the ladle by a crane. The lower steel part 2 forming the lower part of the ladle is also made of normal structural steel. The two parts are connected to each other by flat ribs 3, which are normally welded to the upper steel part 1 and the lower steel part 2. By means of their edges. The flat ribs 3 are of non-magnetic steel or other non-magnetic material. The tangential thickness of the flat fins 3 is selected in relation to the heating frequency used, for example about 15 mm for 50 Hz, the width of the flat fins 3 in the radial direction is selected as small as possible, but to suit the strength. The length of the flat fins 3 in the axial direction of the ladle is about 1.6 times longer than the length of the induction heater coil 5. The heater coil 5 is positioned symmetrically axially along the length of the flat ribs 3. On the outside of the heating coil 5 are transformer plate bundles 6 for guiding the magnetic flux of the heating coil 5. To obtain a better magnetic coupling of the heating coil 5 to the charge, the transformer plate bundles 6 may also have pole extensions 7 also made of transformer plates.

In the cavity of the ladle, a ceramic heat-insulating refractory lining 4 for a given liquid metal is provided in a conventional manner.

The principle of the clarity of the electromagnetic wave pan is that the same magnitude of the magnetic flux of the heating coil 5 is used. which enters the charge at the top of the pan between the flat pans

3 236 158 the ribs 3 _t are returned between the flat ribs 3 in the lower part of the ladle. The resulting magnetic flux in the window, which forms every two flat ribs 3, is thus equal to zero. Therefore, there is also no orbital voltage to push the eddy heating currents. The upper steel part 1 of the ladle and the lower steel part 2 form short threads, but they are already practically out of range of the magnetic flux of the heating coil 5. If necessary, these two parts can be shielded short by copper threads against the magnetic dock of the heating coil 5. sufficiently away from the heating coil.

The invention can be used wherever the metal is to be inductively heated in a portable pan or even in a non-portable pan, which must have a mechanically strong metal jacket.

Claims (2)

Apparatus for electric induction heating of metals, comprising a ladle with a mechanically strong metal jacket surrounded by a heating coil, characterized in that the ladle jacket is formed by an upper steel part (1) and a lower steel part (2) which are connected together by vertical radially oriented the length of the heating coil (5) is 30 to 80% of the distance between the lower edge of the upper steel part (1) and the upper edge of the lower steel part (2). Apparatus according to claim 1, characterized in that beams of transformer plates (6) with pole extensions (7) are arranged symmetrically on the outer periphery of the heating coil (5), wherein the length of the beams of transformer plates (6) is 50 to 100% distance between the lower edge of the upper steel part (1) and the upper edge of the lower steel part (2).