JP2009024941A - Power source damage preventive method for groove type induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source damage preventive method for a groove type induction heating device, relaxing fluctuation of a current to prevent damage of a power source even when a duct is blocked due to adhesion to the duct of foreign matter such as furnace slug involved in molten iron and oxide generated in a furnace in heating the molten iron using the groove type induction heating device having a grooved flow passage. <P>SOLUTION: A refractory material 19 forming the flow passage 23 is previously impregnated with iron, whereby when the passage is blocked due to foreign matter 22 or the like, a current is released to the iron impregnated region 24 so that the current is not completely interrupted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for preventing power supply damage in a grooved induction heating apparatus having a grooved channel, which is installed in a storage furnace for temporarily storing hot metal discharged from a blast furnace before refining in a converter. Is.

The hot metal discharged from the blast furnace is received in a hot metal transfer container such as a torpedo car or hot metal ladle, and after being subjected to preliminary treatment such as desulfurization treatment and dephosphorization treatment as necessary, it is transported to the converter. Decarburization and refining is carried out. At this time, the hot metal may be temporarily stored in the storage furnace before decarburization and refining in the converter in order to adjust the excess and deficiency of the hot metal that occurs due to the timing of brewing from the blast furnace and fluctuations in the processing amount in the converter. is there. Since the hot metal in the storage furnace causes a temperature drop due to heat radiation from an opening such as a tap outlet and heat removal from the refractory, it is necessary to heat the hot metal.
In order to heat the hot metal, an induction heating device (hereinafter also referred to as a groove type induction heating device) having a groove type flow path provided in a storage furnace is used.

  FIG. 5 is a diagram for explaining the heating principle of the induction heating apparatus. This can be explained by a transformer circuit 83 having an induction coil 81 of the iron core 80 as a primary circuit and a one-turn hot metal circuit 82 formed by hot metal filling the flow path as a secondary circuit.

  That is, when the induction coil 81 is energized from the power supply device 84, a magnetic flux F is generated in the iron core 80, and this magnetic flux F is linked to the hot metal circuit 82 to generate an induced current I. It is heated by Joule heat generation.

  In general, the Lorentz force (electromagnetic force) in the direction of contracting the cross section of the flow path acts on the hot metal in the flow path due to the induced current generated in the hot metal in the flow path. This Lorentz force is generally referred to as a pinch force, and the hot metal in the flow path contracts by this pinch force, and when the pinch force is large, the hot metal in the flow path is cut. A phenomenon in which the hot metal in the flow path contracts due to the pinch action and the hot metal in the flow path is cut by the contraction is referred to as a pinch phenomenon.

  When such a pinch phenomenon occurs, the current flowing through the induction coil wound around the iron core fluctuates severely, making it impossible to stably supply the power necessary for heating the hot metal, increasing the load on the power source and It may lead to troubles that damage the circuit.

  Further, since the slag in the furnace and the oxide generated in the furnace that are entrained in the hot metal adhere to the inner wall of the flow path as foreign substances, the flow path is reduced and sometimes the flow path is blocked. Thereby, since the cross-sectional area of the flow path becomes narrow, the induced current flowing in the hot metal per cross-sectional area increases, and there arises a problem that the above-described pinch phenomenon is more likely to occur.

As a countermeasure for this, for example, Patent Document 1 proposes a method of alternately supplying a high-output energization and a low-output energization to an induction coil wound around an iron core, thereby suppressing the blockage of the flow path due to foreign matter. ing.
JP 2004-218038 A

  However, the method disclosed in Patent Document 1 described above has the following problems. That is, the method of Patent Document 1 is a method in which the strength of the flow rate of the hot metal, which is a liquid, is changed to wash out foreign matter, so that only foreign matter with relatively weak adhesion can be washed away, and the flow path is sufficiently blocked. However, there is a problem that the power supply may be damaged due to a pinch phenomenon that cannot be suppressed.

  The present invention has been made in view of such problems, and when heating hot metal using a groove-type induction heating device having a groove-type flow path, in the furnace slag or the furnace caught in the hot metal. Even if a foreign substance such as generated oxide adheres to the flow path and closes the flow path, the power supply damage prevention method in the groove type induction heating device can prevent the power supply damage by reducing the fluctuation of the current. The purpose is to provide.

  In the invention according to claim 1 of the present invention, when induction heating of molten iron stored in a storage furnace using an induction heating device having a groove-type flow path, iron is previously applied to the refractory forming the flow path. A method of preventing damage to a power source of a grooved induction heating apparatus, wherein the current is not completely cut off by impregnating and allowing the current to flow into the iron-impregnated region when the flow path is closed.

  The invention according to claim 2 of the present invention is a groove type induction heating device having a groove type flow path for induction heating of the hot metal stored in the storage furnace, wherein the refractory forming the flow path is The groove type induction heating apparatus is characterized by being impregnated with iron in advance.

  The present invention prevents the current from being completely interrupted by letting the current flow into the iron-impregnated region when the flow path is closed, so that the load on the power supply is prevented from increasing abnormally and the trouble of the power supply equipment is avoided. It becomes possible. As a result, stable heating operation such as improvement in the heating efficiency of the hot metal is achieved, and industrially beneficial effects are brought about.

  Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 3 is a diagram showing a schematic cross section of a heating type storage furnace equipped with a grooved induction heating apparatus according to the present invention. 4 is a schematic cross-sectional view taken along the line B-B in FIG. 3. In the figure, 10 is a storage furnace, 11 is an iron skin, 12 is a grooved induction heating device, 14 is a receiving port, 15 is a spout, 18 is hot metal, and 19 is a refractory.

  As shown in FIGS. 3 and 4, the cylindrical storage furnace 10 has an outer shell made of an iron shell 11, and a refractory 19 is constructed inside the iron shell 11, and a hot metal such as a hot metal ladle or a torpedo car. A receiving port 14 for receiving hot metal 18 from a transport container (not shown), and an outlet 15 for discharging the stored hot metal 18 to a hot metal holding container (not shown) such as a charging pan. Is installed on the side wall of the storage furnace 10.

  Further, four groove type induction heating devices 12 are arranged at the lower portion of the side wall of the storage furnace 10. The hot metal 18 discharged from the blast furnace is subjected to hot metal pretreatment such as desulfurization treatment and dephosphorization treatment as necessary, and then charged into the storage furnace 10 through the receiving port 14, and the grooved induction heating device 12. It is stored with heating. At the time of extraction from the storage furnace 10, the storage furnace 10 is tilted and the molten iron 18 is extracted from the outlet 15.

  FIG. 1 is a schematic cross-sectional view of a grooved induction heating apparatus according to the present invention. FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. In the figure, 20 is an induction coil, 21 is an iron core, 22 is a foreign object, 23 is a flow path, and 24 is an iron-impregnated region. Other reference numerals are the same as those in FIGS.

  As shown in FIGS. 1 and 2, the groove type induction heating device 12 includes an iron core 21 around which an induction coil 20 is wound around a box made of a refractory material that forms a flow path 23 serving as a path for the hot metal 18 to pass through. The flow path 23 communicates with the inside of the storage furnace 10. By causing an alternating current to flow through the induction coil 20, an alternating magnetic flux interlinking with the loop-shaped flow path 23 is generated, and an induced current is generated in the hot metal 18 inside the loop-shaped flow path 23, which is generated by this induced current. The hot metal 18 is heated by Joule heat.

  In addition, the Lorentz force acts on the hot metal 18 inside the flow path 23 by this induced current and the alternating magnetic flux generated by the induction coil 20, and the hot metal 18 moves inside the flow path 23, thereby the inlet of the flow path 23. A flow toward the outlet is formed. That is, the heated hot metal 18 is discharged from the outlet, and instead, the hot metal 18 inside the storage furnace 10 flows into the grooved induction heating device 12 from the inlet, and the hot metal 18 is sequentially heated. In addition, the arrow in the flow path in FIG. 1 has shown the direction of the flow of the hot metal 18. FIG.

  When the hot metal 18 is heated by the grooved induction heating device 12, slag entrained in the hot metal 18, oxide generated inside the storage furnace 10, etc. are deposited on the inner wall of the flow path 23, and the foreign matter 22 Form. The formed and grown foreign matter 22 damages the power supply device due to a sudden change or interruption of the induced current caused by a pinch phenomenon in which the flow path 23 contracts or closes.

  As shown in FIG. 1, the present invention is characterized in that an iron-impregnated region 24 in which iron is impregnated in part or all of the refractory 19 forming the flow path is provided. When the flow path 23 is contracted / blocked, the current flows through the iron-impregnated region 24, so that fluctuations in the induced current are alleviated and the circuit is not completely cut off. By stopping the power supply device during this period (a time margin for stopping the power supply device is created), it is possible to prevent the power supply device from being damaged.

It is a figure which shows the schematic cross section of the groove type induction heating apparatus which concerns on this invention. It is a figure which shows the schematic cross section by the AA arrow of FIG. It is a figure which shows the schematic cross section of the heating type storage furnace provided with the groove type induction heating apparatus which concerns on this invention. It is a figure which shows the schematic cross section by the BB arrow of FIG. It is a figure explaining the heating principle of an induction heating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Storage furnace 11 Iron skin 12 Groove type induction heating apparatus 14 Receiving port 15 Outlet 18 Hot metal 19 Refractory 20 Induction coil 21 Iron core 22 Foreign material 23 Channel 24 Iron impregnation area

Claims (2)

In induction heating of hot metal stored in a storage furnace using an induction heating device having a groove-type flow path,
A groove type characterized in that the refractory forming the flow path is impregnated with iron in advance, and the current is not completely cut off by letting the current flow into the iron-impregnated region when the flow path is closed. A method for preventing power supply damage of an induction heating device. A groove-type induction heating apparatus having a groove-type flow path for induction-heating hot metal stored in a storage furnace,
The groove type induction heating apparatus characterized in that the refractory forming the flow path is impregnated with iron in advance.

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