JPH07260364A - Apparatus for and method of heating and melting metal - Google Patents

Abstract

PURPOSE:To detect excessive/short charging of materials into a furnace and abnormal operation such as hanging or the like by providing an induction coil for detecting a level of materials charged into the furnace and a gravimeter for detecting weights of materials charged into the furnace, in addition to an induction coil for causing heating reaction of heating elements and for heating and melting predetermined materials. CONSTITUTION:A material 2a being melted is transported to a furnace body 4 by a belt conveyor 11 to be charged into the furnace through an opened furnace lid 8. The material 2a being melted is heated by an induction coil 3, comes in contact with a carbon material 1, which has undergone induction heating in a like manner, to be subjected to reducing melting, and then is tapped out of the furnace through a tapping port 5. In this case, a detecting coil 6 for detecting a level of the materials is provided on an upper portion of the furnace body 4, and variation of impedance of the coil is detected for detection of whether the material 2a being melted is accumulated to a position of the coil 6. Also, a gravimeter 7 is provided on a lower portion of the furnace body 4 to detect weights of the furnace body 4 and the materials in the furnace. Further, a control arithmetic unit 23 is provided to detect excessive/short charging of materials into the furnace and abnormal operation such as hanging or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating and melting apparatus for continuously melting a material to be melted such as a metal to continuously obtain a molten metal and a method therefor.

[0002]

2. Description of the Related Art Various heating devices are known in which a material to be melted such as a metal is continuously heated and melted to obtain a molten metal. For example, in Japanese Patent Laid-Open No. 4-17631, another control amount (for example, voltage) and a material input amount are controlled so that any one of power, power, and voltage (for example, power) of a power supply control device is constant. And stable continuous operation is disclosed.

[0003]

SUMMARY OF THE INVENTION The above-mentioned conventional apparatus is used in an operation in which the power supply set value (any one of electric power, voltage, and current) of the power supply control device, the material input amount, and the furnace body capacity are matched. There was no problem, but there is no detection mechanism during abnormal conditions such as unmatching due to various operating modes and various materials used, and further due to rack hanging phenomenon in the furnace, which affects continuous operation. There was a problem.

The present invention is based on the above-mentioned unmatching,
By installing a safety control device that detects a hanging phenomenon (a phenomenon that a cavity is created in the middle of the furnace), displays each alarm, and automatically changes each set value if necessary,
The purpose is to enable stable continuous operation.

[0005]

In order to achieve the above object, according to the present invention, a weighing scale for detecting that a material corresponding to the capacity of the furnace body is charged, and the height of the furnace body to which the material is applied are measured. An induction coil for detecting whether or not there is provided, and an arithmetic and control unit for detecting and controlling the abnormality and its cause are provided.

[0006]

A weighing machine such as a load cell for measuring the weight of the furnace body detects whether or not an appropriate material is charged according to the capacity of the furnace body. The induction coil detects if the material has been charged to the proper position in the furnace body. The control arithmetic unit
By inputting the above data, the output of each alarm and the command to change each set value are performed as necessary.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, FIG. 1 will be described. Material to be melted 2
A is conveyed to the furnace body 4 by the belt conveyor 11, opens the furnace lid 8 and is put into the furnace. The material to be melted 2b charged in the furnace is heated by the induction coil 3 and further comes into contact with the carbon material 1 which is also induction heated in the furnace to be reduced and melted. It is heated and tapped from the tap hole 5 to the outside of the furnace.

Here, the material to be melted is set to a constant value with any one of the power, current and voltage applied to the induction coil (however, this embodiment will be described as voltage hereinafter). The charging is controlled in the furnace so that (For this charging method, for example, Japanese Patent Laid-Open No. 4-17631
The technology disclosed in the publication is available. That is, the amount of material input changes due to the change in the set value of this voltage. If this setting is mistaken, the amount of material to be melted in the furnace becomes abnormally small, or if the capacity of the furnace body 1 or more is exceeded. There is a problem that the material to be melted 2 is added. Therefore, in the present invention, the amount of material input into the furnace is detected by measuring the weight of the furnace body, and the amount of material input is controlled to fall within the set value range. In addition, even if there is no problem in the material input amount in the furnace, considering that there is a possibility that the material may be charged more than the height of the furnace body 1 due to hanging or the like, the material height above the furnace body 1 may be considered. The detection coil 6 is set. Impedance Z (Ω) of this induction coil 6 = 2
πfL, and the inductive reactance L of this coil 6 is proportional to the permeability μ of the substance traversing that coil. For example, when the melted material 2b has a magnetic permeability 300 times or more higher than that of the atmosphere, such as cast iron, the impedance Z is large depending on whether or not the melted material 6 is deposited at the position of the material detection coil 6. Since they are different, it is possible to easily detect whether or not the material to be melted 6 is deposited up to the position of the material detection coil 6 by detecting the change in the impedance Z. Iron materials such as cast iron have the property of rapidly losing their magnetism above the Curie point (about 770 ° C), but unlike the crucible type furnace such as the high / low frequency furnace, the vertical direction in the furnace Since there is a temperature gradient and the temperature is below 200 ° C in the upper part, there is no problem of losing magnetism.

A method of detecting the material to be melted by using a camera or the like is also conceivable. However, this method requires that the furnace lid 8 be kept open at all times, which makes it difficult to collect the exhaust gas and simultaneously This method is superior because it has a problem in that it is difficult to establish a reducing atmosphere by shutting off from the outside.

Next, the control method will be described with reference to FIG. Material height detection coil current 21 and furnace body weight 2
2 is input to the arithmetic and control unit. First, it is determined whether the furnace weight 22 is within a preset range, and if it is above the range, an "excessive material" alarm is output and the operating voltage setting is changed, and the charging is stopped or charged depending on the amount of material charged. Outputs a quantity reduction command.

If the current of the material height detecting coil 6 is below the set value (that is, the material height is large) even within the weight setting range or below, an alarm of "hanging up" is displayed,
Take mechanical or operator action.

Next, when the weight is less than the set range and the current value is more than the set value, the amount of material input is too small, so that an "insufficient material" alarm is displayed and the operating voltage is changed and the amount of material input is increased. The increase command of is output.

In other cases, it is regarded as a steady operation and the control of the previous loop with the same set value is continued.

Although not shown in FIGS. 1 and 2, a plurality of material height detecting coils 6 are provided, one for interlock, one for alarm, and another for normal operation detection. It is also possible to use a method such as "ni".

[0015]

According to the present invention, by providing the coil for detecting the material height, the weight scale for measuring the weight of the furnace body, and the arithmetic control device for controlling the same, It is possible to detect abnormalities such as excessive / small amount of material input in the furnace and hanging, and it is possible to take safety measures.

2. Even if the operating voltage settings do not match, stable operation can be performed by automatic control.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a melting apparatus according to the present invention.

FIG. 2 is a flow chart showing an operation flow of the melting apparatus shown in FIG.

[Explanation of symbols]

1 ... Carbon material, 2a, b ... Material to be melted, 3 ... Induction coil,
4 ... Furnace body, 5 ... Tap, 6 ... Coil for detecting material height, 7
... Weighing scale, 8 ... Furnace lid, 11 ... Belt conveyor, 12 ... Belt conveyor motor, 13 ... Furnace power supply control device, 2
DESCRIPTION OF SYMBOLS 1 ... Current detector, 22 ... Weight detector, 23 ... Control arithmetic unit.

Claims (5)

[Claims] 1. A melting apparatus comprising a heating element made of a conductive refractory material as a heat source and a furnace wall for accommodating the heating element, wherein a predetermined material is melted and then passes between the heating elements.
In addition to an induction coil for heating the heating element and heating and melting a specified material, an induction coil for detecting the height of material input into the furnace and a weighing scale for detecting the weight of material in the furnace are installed. apparatus. 2. The melting apparatus according to claim 1, wherein an induction coil for detecting a material charging height in the furnace and a weight of the material in the furnace are detected to detect an excessive amount / insufficient amount of material in the furnace and a shelf. A method characterized by detecting and displaying an abnormal operation such as suspension. 3. A melting furnace for melting a material whose magnetic permeability changes according to the melting state, a coil provided above the melting furnace, a power supply for supplying a current to the coil, and a current flowing through the coil. Of the melting furnace, and a controller for controlling the operation of the melting furnace according to the detection output from the detector. 4. A melting furnace for melting a material whose magnetic permeability changes according to the melting state, a coil provided above the melting furnace, a power supply for supplying a current to the coil, and a current flowing through the coil. Of the detector, and an alarm device that issues an alarm according to the detection output from the detector. 5. A coil is provided in the upper part of a melting furnace for melting a material whose magnetic permeability changes according to the melting state, and a change in the flowing current is detected while the current is passed through the coil, and the above-mentioned is detected according to the detection result. A method for controlling a melting apparatus for controlling the operation of a melting furnace.