CS241818B1 - Inductor for medium frequency heating of blanks and cuts - Google Patents

Abstract

The solution concerns an inductor for medium-frequency heating of blanks and shears made of shorter sections. ■The essence of the invention is the structural modification of the inner faces of individual sections of the inductor, which prevents short-circuiting or reduces the insulation resistance between the guide rail and the winding of the induction coil. The face with the formed opening for cooling is made of a thermally conductive, preferably metal material. The inner face is separated from the lining in the upper part on half of its inner circumference by a second insulating insert, while there is an air gap between the end of the winding of the induction coil and the face.

Description

BACKGROUND OF THE INVENTION The present invention relates to an inductor for medium frequency heating of cuts and shavings formed from shorter sections.

Previously manufactured mid-frequency heating imducers with lengths of 1.7 to 3 m had inductor coil windings either split, about 1 m, or whole. The lining was not split in both cases. This embodiment had a number of disadvantages, the most serious of which were the difficulty of choking the lining at the indicated lengths and the necessity of using a sliding molding mandrel, which adversely affected the quality and durability of the lining.

For these reasons, the imductors are divided into approximately one-meter sections with split winding and lining. Both the outer and inner faces of the individual sections are made of hardened fabric. The internal face joint is sealed with a heat-resistant seal. Between the induction coil winding and the lining, an insulating insert made of micafolia and silicone lacquered glass fabric is inserted over the entire length of the section at the bottom about half of the inner circumference.

These measures are used to increase the insulation resistance between the winding and the guide rails mounted on the lining on which the heated material slides. By pre-drying the lining prior to commissioning the inductor, water is removed to moisten the lining during ramming; however, crystalline bound water is not removed, which is released at a temperature of about 400 ° C.

It is not possible to pre-dry the inductor at this temperature because the binder between the winding and the supporting sidewalls would be damaged. In addition, the sidewalls and fronts would also be burned.

When the inductor is connected to the heater, including the cooling circuits and the lining is heated above 400 ° C, crystalline bound water is released and until its evaporation predominantly inside the inductor the lining becomes conductive and between the guide! bars and windings could occur, and without the insulating insert 5, short circuits would actually occur. In order not to burn and burn the front plates from the hot lining, the outer windings 3 of all sections are extended, thereby separating the front plates from the lining and prevent sunburn.

This embodiment, however, has the disadvantage that the surface distance of the lining and the winding has only a value of the thickness of the insulating insert, i.e. about 0.5 mm, in the case of wet lining due to the released crystalline bound water and hence also wetted refractory seals between the faces may cause short circuits or poor insulation resistance.

The consequence is the necessity of long-term drying at higher temperatures directly on the heater, replacement of the refractory seal and possibly further drying after the heater.

The above-mentioned drawbacks are overcome by an inductor for medium frequency heating of billets and chunks according to the invention. The face with at least one cooling opening is made of a thermally conductive, preferably metallic material. The inner face is at the top half of its inner circumference separated from the lining by a second insulating insert, with an air gap between the end of the coil winding and the face.

The advantage of the construction of the inductor according to the invention is the safe separation of the guide bar and the winding of the induction coil, where no short-circuit or reduction of the insulation resistance after release of the crystalline bound water in the lining can occur.

The present embodiment of the inductor is shown in the attached drawing.

The faces 7 have openings 8 for cooling around their circumference. The inner faces 7 of two adjacent sections are sealed with a heat-resistant seal 2. The ends of the induction coil windings 3 do not extend up to the heat-resistant seal 2 and do not touch the conductive faces 7.

In the epode part of the lining 4 on the half of its outer perimeter there is a first insulating insert 5 along the entire length of the section that separates the lining 4 from the induction coil winding 3 and from the face 7. This insert is not disposed over the entire length of the section, but only covers the inner surface of the opening of the faceplate 7 and the extreme thread of the coil winding 3.

A guide rail 6 is then mounted on the lining 4 at the bottom thereof. The ends 7 are separated from the lining 4 by. its entire perimeter. Furthermore, they are not conductively connected to the coil winding 3. The distance between the guide rails 6 and the upper part of the coil winding 3, which is not separated by insulation from the lining 4 along its entire length, is sufficient, even with a wet lining 4,

The design is of particular importance for the inner ends 7, but is also applicable to

Claims (1)

SUBJECT Mid-frequency inductor heating of cut and trimmed sections, consisting of sections separated by a refractory seal, the linings of which are at the bottom half of their outer circumference covered by a first insulating insert, characterized in that the inner faces (7J with at least one aperture (8J) for OF THE INVENTION the cooling, made of a thermally conductive material, is at the top half of its inner; The air gap is between the end of the induction coil winding (3) and the end (7).