SU592381A3 - Channel-type induction furnace - Google Patents

Description

The invention relates to the field of electrothermal. Known induction channel furnaces containing a bath, under which the inductor and the magnetic core 1, 2 are placed. However, these furnaces have a sufficiently high reactive power. Closest to the invention known is an induction channel furnace containing a bath and an inductor located in the form of at least two coils placed on the magnetic core, at least on one side of the channel for the circulation of molten metal made in lining 3. Such a furnace also does not have a sufficiently high power factor, does not allow to supply a significant voltage to the inductor's capacitance and to increase the capacity of the furnace. The goal of the invention is to reduce the reactive power of the furnace. the magnetic conductor is threaded through their middle. In order to prevent the molten metal from falling on the coils, the cooling system is made in the form of at least two flat spirals from the tube, repeating the shape of the coil, arranged parallel to the coil from the channel side. An additional cylindrical inductor coil can also be placed on the side of the radio conductor, threaded through the middle of the coils, provided with additional cooling system elements parallel to it. FIG. 1 shows an induction channel furnace, single channel version; in fig. 2 - the same, multi-channel version; in fig. 3 shows a schematic arrangement of a coil and a cooling channel; in fig. 4 - two rows of coil, cross section; in fig. 5 - distribution of magnetic current in a water channel variant; in fig, b - docking of conductors of rows of coils; in fig. 7 is a drive coil, side view; Fig. 8 is a cooling coil, side view; in fig. 9 and 10 are the placement of cooling elements in a multichannel embodiment. The induction duct furnace contains an inductor 1 located under the melting bath 2 furnaces. Lo both sides of channel 3 .al

Circulations of the molten metal are flat spiral coils 4 arranged parallel to each other and the channel plane. On the inner side of the coils, parallel to them are two rows of cooling elements 5, each of which is made in the form of flat spirals repeating the shape of the coil. A closed laminated magnetic circuit 6 is threaded through the middle of flat coils.

Such a furnace consumes low reactive power, often about half the power required for a conventional furnace, and differs from a conventional furnace with reduced leakage and improved induction between the coils and channels. The working flow will also be small and therefore a relatively small iron core can be used. The need for space is also small, and if necessary, the capacity of the furnace can be easily increased. The furnace design also makes it easy to replace the lining.

Inductor 1 Attaches to the oven tightly or removably. The metal in the channels serves as a secondary circuit. The electric current induced in the secondary circuit heats and melts the metal.

The power achieved in a single-channel inductor is expressed by the following equation:

c

R

(

where and is voltage, is active resistance, X is reactive resistance.

There are four possibilities to increase power (with cosf 0.7): an increase in voltage, resistance, reactance, or number of channels per unit inductor.

As the voltage increases, leakage will increase, resulting in unwanted heating by the eddy currents of the structure itself. With increasing resistance, the temperature in the channel increases, however, the increase in resistance is limited by the limiting temperature that the ceramic cladding withstands. Reducing the reactance can be achieved by improving inductive coupling, reducing the distance between the channel and the coil, making the channel more flat, etc. The ceramic lining thickness and the need for space, etc. are the factors that determine the lower limit. reactive resistance.

The power supply of the primary winding coil is usually single phase, but it can be multiphase, the current frequency is 50-60 Hz.

The arrangement of the coils one on each side of the channel (Fig. 3) allows the channel to be narrow in comparison with the height, which, in combination with the shape of the coil, provides a good inductive connection between the coil and the channel. The distance a can be reduced, and the channel plane is increased. This makes it possible to select the thickness of the lining and select a cross section for the channel.

The flat coil (Figs. 4, 6) has two levels located on the same axis one after the other, and a cooling channel 7 is formed in it.

The current and the cooler are fed to the inlet 8 and removed from the outlet 9. Between the winding levels there is an insulating layer 10, and between the coil and the core there are cooling elements in the form of gaskets 11. The two inner conductors of the coil are fused together and in them electric current and water can flow down and up through the indicated levels. The coils are connected to each other in series or in parallel.

The cooling elements 5 are placed between the channels (see Fig. 9) between the cooling pads 12, which are made, for example, of copper sheet with cooling holes arranged longitudinally inside.

The induction furnace may have an additional cylindrical coil 13 of the inductor primary winding with cooling elements 14

The flat shape of the multi-level coils reduces the risk of the coil cracking or molten metal penetrating it.

When parsing, first remove the core and the cooling gasket, after which the inductor is turned over and the lining falls out together with the coils.

The magnetic core is also used as support for flat coils and other parts of the inductor. The function of the flat blades is also partial or full support for the lining of the inductor. Sometimes cooling elements can independently perform

the functions of the coils as supporting elements between the channels and due to their cooling effect, they can increase the capacity of the inductor.

Claims (3)

1. Induction duct furnace containing a bath and an inductor located under it. in the form of at least two coils placed on the magnetic core, at least on one side of the channel for the circulation of molten metal, made in the lining, characterized in that, in order to reduce the reactive power, in the lining of the furnace are placed the cooling system and the inductor coil, made in the form of flat spirals of water-cooled tubes laid at least one row parallel to the vertical plane of the channel, and one side of the closed laminated magnetic circuit passes through their middle. 2. A furnace according to claim 1, characterized in that, in order to prevent molten metal from falling on the coils, the cooling system is made in the form of at least two flat coils from the tube, repeating the coil shape, arranged parallel to the coil from the channel side. 3. Furnace on PP. 1 and 2, characterized in that on the side of the magnetic circuit, threaded through the middle of the coils, an additional a cylindrical inductor coil equipped with additional elements of the cooling system, arranged parallel to it. Sources of information taken into account in the examination: 1. USSR Author's Certificate No. 212400, F 27 D 11/06. 1965. 2. US patent number 3551587, 13-29, 1970. 3. USSR Author's Certificate No. 362180, F 27 D- 1/00, 1970. $$; $$: $$$$: BUT Fig.Z Q