JPH09122901A - Method and device to induction-heat fire resistant molded part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly and uniformly heat a refractory formed parts by inserting an inner inductor into an internal space, heating the formed parts by the inner inductor, and taking out the inner inductor out of the internal space. SOLUTION: An inner inductor 4 is inserted in a cylindrical tubular internal space 2. The inner inductor 4 is provided with a cooled spiral induction coil 5, and the induction coil is connected to a generator 6. The induction coil 5 is matched with the internal space 2 in its dimension, in particular, in its length, so as to be extended over the whole length. In addition, the diameter is matched with the internal space 2. To prevent a dipping nozzle from being brought into contact with a part to which the voltage is applied, and/or to prevent the local overheating, the internal space 2 is electrically and/or thermally insulated from the induction coil 5 by a layer 13, e.g. ceramics glaze.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of induction heating a refractory molded part having a tubular interior space. The invention further relates to an apparatus for performing the method.

[0002]

2. Description of the Related Art Molded parts of this kind are parts of melt-pouring devices, especially in metallurgical vessels. These are preheated in order to avoid undesired cooling of the flowing melt, especially its freezing.

Published German patent application No. 3842
In 690, a refractory spout for continuous casting equipment is shown. The spout passage is surrounded on the outside by an induction coil, by means of which the inner and outer walls can be controlled and induction heated. The coil is a component of the spout part. As a result, this component is laborious and expensive, which is especially important because such refractory spout molding parts are consumable parts.

Normally, refractory spout molded parts, especially dip spouts, are heated by a gas burner. This means
In that case, there is a drawback that carbon, which is a material component of the molded part, may be burned. Furthermore, it is undesirable to cause a non-uniform temperature distribution in the molded part during heating. For example, a temperature difference of about 400 K was confirmed. Moreover, heating requires a considerable amount of time.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to enable the rapid and uniform heating of refractory molded parts.

[0006]

According to the invention, the aforesaid problems are solved in a method as described at the outset as follows. That is, the inner inductor is inserted into the inner space, the molded part is heated by the inner inductor, and then the inner inductor is removed from the inner space.

In this case, a rapid and uniform heating of the refractory component, for example the immersion spout or the pipe of the pipe-in-pipe system in which the melt outflow is interruptable and / or controllable or adjustable, takes place.

According to the present invention, increased equipment utilization is achieved because the problem of freezing is avoided. The method and apparatus are suitable not only for heating at the start of casting, but also for heating during interruption of casting in order to maintain the molded part at a suitable temperature.

The device for carrying out this method is advantageous in that the inner inductor is formed mainly from a cooled spiral induction coil.

Advantageous configurations of the invention are apparent from the dependent claims and the following description of exemplary embodiments.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An immersion spout (immersion casting tube) known per se for its form is a fire-resistant molded part 1 made of a ceramic material containing carbon, which molded part is
It can be inductively coupled to the alternating electric field that results in heating. The dip spout has a cylindrical tubular interior space 2. The dip spout has a metallic outer peripheral surface 3 in the outer part area. Therefore, since the metallic outer peripheral surface 3 shields the electromagnetic field from the immersion pouring port, the immersion pouring port cannot be uniformly heated by the outer induction coil.

In the state shown in the drawing, the inner inductor 4 is inserted in the cylindrical tubular inner space 2. The inner inductor 4 comprises a spiral cooled cooled induction coil 5, which is connected to a generator 6. The induction coil 5 is then fitted in the internal space 2 so that its dimensions, in particular its length, extend over the entire length of the internal space 2 as far as possible. Furthermore, its diameter is
It is matched to the diameter of the internal space 2.

In order to prevent the immersion spout from contacting the part through which the voltage is applied and / or to prevent local overheating, the internal space 2 is connected to the induction coil 5 by means of a layer 13, for example a ceramic glaze. It is electrically and / or thermally insulated.

In another configuration of the invention, the induction coil 5
The outer surface of is electrically and / or thermally insulated from the surface of the inner space 2 by the tube portion 7.

It is also advantageous to adapt the induction coil 5 to different geometries or wall thicknesses so that there are different distances between the induction coil 5 and the surface of the area to be heated. This procedure produces different energy densities in the molded part 1, which improves the heating uniformity at different wall thicknesses. The tube section 7 is correspondingly configured.

The tube portion 7 is also used for the central placement of the induction coil 5 in the interior space 2. Since the tube portion 7 is frictionally coupled onto the induction coil 5,
It can be replaced if necessary. The outer diameter of the tube portion 7 is matched to the inner diameter of the inner space 2 so that it can be easily pushed into the inner space 2 and pulled out from the inner space 2 together with the induction coil 5. However, the construction may be such that the tube section 7 is first pushed into the interior space 2 and then the induction coil 5 is pushed into the tube section 7.

The tube section 7 has a flange 8 on the upper side to limit the indentation. In the present example it is closed on the underside by a bottom 9.

Immersion spout with its spread head area 10
The induction coil 5 is also heated at
With an additional winding 11.

The tube portion 7 is made of highly heat resistant ceramic fiber or foam material.

The tube section 7 need not extend the entire length of the induction coil 5. Two or more tube sections may be provided in the length of the induction coil 5.

The one or more tube sections 7 may not be able to be withdrawn from the interior space 2. One or more tube sections 7 may be configured as a lining of the interior space 2, which lining is then decomposed by the melt during the first use.

In order to prevent the immersion spout from radiating, ie, losing heat, when it is heated, it preferably has an outer insulation 12 of ceramic fiber material or ceramic foam. You can This improves the rapid and uniform heating of the dip spout.

When attempting to heat the immersion spout, the inner inductor 4 with its tube portion 7 is inserted into the inner space 2 and the generator 6 is turned on. The dip spout is thereby induction heated, generally over its entire length, quickly and uniformly. After reaching the target temperature, the inner inductor 4
Is withdrawn from the dip spout. The dip spout is then preheated and prepared for casting operation.
The inner inductor 4 can be utilized in multiple immersion spouts for multiple heating processes. As a result, its working capacity does not depend on the consumption of the immersion spout. Pipe part 7
When it is exhausted, it can be withdrawn from the induction coil 5 and replaced with a new tube section. If the inner diameter of the dip spout is different, it is possible to prepare a tube section 7 with a correspondingly different outer diameter. Therefore, even when the diameters of the internal spaces are different, the induction coils 5 can be coaxially centered and inserted.

[Brief description of the drawings]

FIG. 1 shows a dip spout for a metallurgical vessel with an inner inductor inserted.

[Explanation of symbols]

 1 Molded Parts 2 Inner Space 4 Inner Inductor 5 Induction Coil 7 Pipe Part 12 Outer Insulation Part 13 Insulation Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical location H05B 6/36 H05B 6/36 D (72) Inventor Rieudegel Grau Austria Graz Rudolf-Hans -Baltiilles-Syuttrace 22 (72) Inventor Daniel Grimm Federal Republic of Germany Bad Syuv Arbatha Light Alley 18 (72) Inventor Steve Lee United Kingdom Scottland Cardross Liver Beau Crescent 6

Claims (15)

[Claims] 1. A method for inductively heating a refractory molded part having a tubular internal space, wherein an inner inductor (4) is inserted into the inner space (2) and the molded part (1) is formed by the inner inductor (4). ) Is heated and then the inner inductor (4) is removed from the internal space (2). 2. Process according to claim 1, characterized in that the molded part (1) is a refractory immersion cast tube. 3. Device for carrying out the method according to claim 1 or 2, characterized in that the inner inductor (4) is formed mainly from a cooled spiral induction coil (5). 4. Device according to claim 3, characterized in that the dimensions of the induction coil (5) are matched to the dimensions of the internal space (2) of the refractory molded part (1). 5. A layer (13) electrically and / or thermally insulating between the induction coil (5) and the internal space (2), characterized in that: 4. The device according to 4. 6. The distance from the surface of the fire-resistant molded part (1) to be heated to the induction coil (5) is set so as to be able to transfer various amounts of energy. Device according to one of claims 3 to 5. 7. Device according to one of claims 3 to 6, characterized in that the induction coil (5) is arranged centrally in the interior space (2) of the molded part (1). 8. A tube section (7) surrounding the induction coil (5) for centering the induction coil (5) centered within the interior space (2) of the molded part (1). Device according to claim 7, characterized in that 9. One or more tube sections (7) can be overlaid on the induction coil (5),
The device according to claim 7 or 8. 10. One or more tube sections (7) in the induction coil (5) are replaceable,
Device according to one of claims 7 to 9. 11. Device according to one of claims 7 to 10, characterized in that one or more tube sections (7) consist of an electrically and / or thermally insulating material. 12. Device according to claim 7, characterized in that the one or more tube sections (7) consist of a ceramic fiber material or a ceramic foam material of high heat resistance. 13. One or more tube parts (7) are arranged in the interior space (2) of the molded part (1) as at least a partial lining thereof,
Device according to one of claims 7 to 12. 14. Device according to claim 13, characterized in that the lining in the internal space (2) of the molded part (1) is decomposed after heating. 15. Molded part (1), characterized in that it has an outer insulation (12), preferably of ceramic fiber material or ceramic foam material.
The device according to one of the items 4 to 4.