RU1815811C - Work-coil for heating movable articles - Google Patents

Abstract

SUMMARY OF THE INVENTION: An inductor comprises a water-cooled current lead, U-shaped sections of a magnetic core, which are installed with a gap from each other. The sizes of the inductor elements are related by a certain ratio. 2 ill.

Description

The invention relates to metallurgy and mechanical engineering and can be used to heat sheet, pipes and steel structures before deformation and for heat treatment.

The aim of the invention is to increase the operational reliability of the inductor and the quality of heating.

In FIG. 1 schematically shows a General view of the inductor; in FIG. 2 is a section AA in FIG. 1.

, The inductor for heating the moving products contains a water-cooled current path 1 of width A, each section of which is covered by a U-shaped section of the magnetic circuit 2 with a width of pole B. Between adjacent sections of the magnetic circuit there are air gaps 3 of width G.

The sections of the magnetic circuit are fixed on a non-magnetic carrier beam using special brackets made of dielectric material (not shown in FIG., Since they are auxiliary elements of the inductor design) at a distance E from the article 4. The sections of the magnetic circuit 2 are fixed to

active sections of the current lead 1 without electrical insulation and gaps with welds 5.

The sections of the magnetic circuit with the length n (5.0 ... 80.0) A are fixed on the active sections of the current path without being displaced relative to each other symmetrically to the longitudinal axis of the inductor.

The inductor operates as follows.

They turn on the power and supply voltage to the current path 1 of the inductor. Eddy currents are induced in article 4 and heating of the metal of the article begins. When the rolling temperature is reached, the product begins to move relative to the inductor and, in proportion to the increase in speed, the voltage on the current lead is increased until the required technological parameters for heating the product at the outlet of the inductor are achieved.

When the end of the product approaches the end of the inductor, the latter is turned off until the next product enters the zone of its operation and the heating cycle is repeated.

An inductor of the described construction with a power of 280 kW was manufactured and tested at a supply voltage frequency of 1.0 kHz. That (L

WITH

oo eat

00

the piping is made of a square-shaped copper tube (size mm) with a wall thickness of 2.0 mm and is curved by a snake with a length of straight sections of 115 mm.

The sections of the magnetic circuit with a width of 35.0 mm are assembled on the active sections of the current lead from transformer iron plates 0.3 mm thick without insulation and gaps between them with a set length of mm with a pole height of mm and a width of mm, and each of the plates is welded at the root of the pole seam height, 0 mm, section 10 mm2.

The number of active sections of the inductor and sections of the magnetic circuit was set equal to 22 with a total length of the magnetic circuit of 875 mm and gaps between the sections, 0 mm.

Magnetic core sections are aligned in space with lateral faces both in height and in length with an accuracy of 1.0 mm. The parallelism of the axes between the active sections of the current lead is maintained with the same accuracy, i.e. fluctuations in dimensions G and D along the length A of not more than 1.0 mm at mm.

The magnetic circuit is fixed in space on a rigid stainless steel beam using ceramic brackets to prevent sections from moving relative to each other in the vertical and horizontal planes and isolating them from the beam.

The inductor was tested in the process of heating samples of steel 17G1S-U with a thickness of 12.0 mm for 380 hours with cyclic on and off.

When the distance from the magnetic circuit to the surface of the sample was established, 0 mm and heated during movement at a speed of 1.0 m / min to 1000 ° C, the non-uniformity of the metal temperature across the width of the heating zone and the thickness at the outlet of the inductor did not exceed + 10 ° C.

To determine the stability and reliability of the inductor, the flow rate of cooling water was changed from 2.0 m / min to completely turn it into steam, and the water supply was completely stopped for a short time up to 10 seconds without changing the heating mode.

Inductor of known design after 150 hours under similar operating conditions

was stopped to repair charred micanite electrical insulation, as its further exploitation would lead to cracking of the insulation and short circuit.

Thus, the design of the inductor provides a significant increase in operational reliability due to the exclusion of burnable electrical insulation from the heating zone, increases the efficiency and uniformity of heating of the product due to the clever placement of the sections of the magnetic circuit in space with a minimum distance from the surface of the product.

Claims (1)

The claims An inductor for heating movable products, comprising a zigzag water-cooled current path, the active sections of which are located in the grooves of the magnetic circuit, characterized in that what. in order to increase the operational reliability of the inductor and the quality of heating, the magnetic circuit is made in the form of U-shaped sections, each of which is connected to the active section by a permanent connection, the sections are installed one from the other with a gap between their side faces, while the width of the current-carrying tube equal to A (5.0-25.0) mm, and the size of the specified gap G and the pole width of the magnetic circuit B selected respectively from the following relationships; O.ZA G 0.5A, B (0.2-0.7) A. FIG. 1