JP3149647B2 - Metal layer detector for melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal layer detecting device for a melting furnace for detecting a metal layer generated above a molten metal (molten metal) being melted by the melting furnace.

[0002]

2. Description of the Related Art Conventionally, various alloys such as a Ni-based alloy, a Co-based alloy, and a Cu-based alloy are prepared by mixing raw materials weighed and mixed so as to have a predetermined alloy composition in a vacuum induction melting furnace, a high-frequency induction melting furnace, It is melted by a melting method most suitable for each alloy, such as a frequency induction melting furnace, and this melted alloy is processed into intermediate materials such as ingots and slabs by continuous casting method, etc., while it is formed into welding rods, castings, etc. Has been cast.

[0003]

In the case of melting the raw material by the melting method, a vertically long melting furnace is often used because of its high thermal efficiency.
As shown in the figure, the newly charged raw material 1 is caught above the molten metal 3 in the furnace 2 depending on its shape to form a metal layer 4,
Alternatively, the molten metal component solidifies from the inner surface 2a of the furnace 2 toward the center above the molten metal 3 as shown in FIG. 5 to form an alloy layer 5, or the molten metal 3 is oxidized as shown in FIG. The resulting metal oxide layer 6 covers the surface of the molten metal 3 or covers the lower part of the newly charged raw material 1,
There was a problem that troubles such as hindering the drop of the raw material 1 occurred.

[0004] Above the molten metal 3, the metal layer 4, the alloy layer 5,
When the oxide layer 6 and the like are formed, the raw material 1 added later does not fall into the molten metal 3, and the molten metal 3 is covered with the metal layer 4, the alloy layer 5, the oxide layer 6, and the like. At the moment when the temperature of the molten metal 3 rises, the internal pressure of the molten metal 3 rises, and a portion of the metal layer 4, the alloy layer 5, the oxide layer 6, etc., falls into the molten metal 3, or at the moment There is a possibility that the molten metal 3 will be bumped at the moment when a part of 4 to 6 is melted to form a hole. Also,
If the melting furnace 2 is overheated, there is a risk that the furnace material will be melted and the coil will melt. When the coil is melted, there is a danger that steam explosion may occur due to cooling water flowing in the coil, which is extremely dangerous.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a metal layer detecting device of a melting furnace which can quickly detect a metal layer formed above a molten metal.

[0006]

In order to solve the above-mentioned problems, the present invention employs the following apparatus for detecting a metal layer in a melting furnace. That is, an apparatus for detecting a metal layer generated above a molten metal being melted by a melting furnace, wherein at least one of electric power, current or voltage supplied to the melting furnace is measured at a predetermined time interval. Detecting means for taking in as measurement data; comparing the measurement data at a predetermined time among the measurement data output from the detection means with the measurement data after a predetermined time has passed from the predetermined time; And determining means for determining that a metal layer exists when the difference between the two is equal to or less than a preset value.

[0007]

In the apparatus for detecting a metal layer of a melting furnace according to the present invention, the detecting means measures at least one of electric power, current or voltage supplied to the melting furnace at a predetermined time interval and takes in as measurement data. Compares the measurement data at a predetermined time among the measurement data output from the detection means with the measurement data after a lapse of a predetermined time from the predetermined time, and a difference between the measurement data is equal to or less than a preset value. By determining that a metal layer exists in the case of, the metal layer generated above the molten metal is quickly detected, and the raw material is caught above the molten metal, or the raw material solidifies above the molten metal to form an alloy layer. In addition, it is possible to prevent the occurrence of problems such as that the oxide covers the surface of the molten metal. This makes it possible to prevent undissolution of the raw material, bumping of the molten metal, melting of the furnace material, and the like.

[0008]

FIG. 1 is a block diagram of an apparatus for detecting a metal layer in a melting furnace according to an embodiment of the present invention. This metal layer detecting device 21
Is a device for detecting a metal layer generated above the molten metal during melting, and includes a furnace 2 and a power supply 22 for supplying power to the furnace 2.
A detection unit (detection means) 24 which is connected to the medium frequency induction melting furnace 23, which is configured to measure the power supplied to the furnace 2 at predetermined time intervals, and takes in the power as power data (measurement data); Comparing the power data at a predetermined time and the power data after a predetermined time has elapsed from the predetermined time among the power data output from the detection unit 24,
A determination unit (determination means) 25 that determines that a metal layer exists when the difference between the power data is equal to or less than a preset value. Here, the medium frequency induction melting furnace 23 uses a magnetic triple frequency converter.

Next, the operation principle of the metal layer detecting device 21 will be described with reference to FIG. When the raw material is charged into the furnace 2 and the supply of electric power is started, the reactance (L) fluctuates as the charged raw material is melted, causing a mismatch with the capacitor (C) and reducing the power (0 to t). _{Between 1} ). Therefore, the power factor is adjusted by adding a capacitor, the reactance (L) is matched with the capacitor (C), and the power is increased to melt the raw material (between t _{1 and} t ₂ ). As the raw material is melted, the reactance (L) fluctuates again, causing a mismatch with the capacitor (C) and reducing the power (t
Since between ₂ ~t _3), during the dissolving the starting material (t ₃ ~t ₄ increases the power take matching with the adjusted power factor reactance by adding a capacitor again (L) and capacitor (C) ).
By repeating the above operation, the charged raw materials can be sequentially dissolved.

Here, for example, when the newly charged raw material is caught above the molten metal in the furnace 2 due to its shape and forms a metal layer, there is no change in the reactance (L), so that it matches with the capacitor (C). The power is kept constant (between t ₄ and t ₅ ). However, since the power Similarly, when the raw material temperature of the completely burn through and solution water into the molten metal is increased is constant, in order to distinguish it, dissolving time interval between t ₄ ~t ₅ The formation of the metal layer can be accurately detected by deciding in consideration of various conditions such as the input amount of raw materials at the time, the timing, the method of supplying power at the initial stage and during melting, and the like.

Next, a more specific method of capturing and determining the power data of the metal layer detecting device 21 will be described with reference to FIG. Here, the detection unit 24 is the furnace 2
Is measured at one-minute intervals and fetched as power data, and the determination unit 25 outputs the power data d at the first time (0 minutes) of the power data output from the detection unit 24.
₀ compared after 10 minutes and power data d _10. here,
If the difference Δd between the power data d ₀ and the power data d ₁₀ exceeds the preset value D, the power data d ₁ after one minute and the power data d ₁₁ after 11 minutes are compared. Thus, 2
When the difference Δd between the two power data exceeds the preset value D, the two power data are sequentially compared.

Thereafter, as shown at point A in the figure, when the power value rises sharply, the power factor is adjusted by adding a capacitor to match the reactance (L) with the capacitor (C). Then, the power data so far is erased, and the power is newly measured at one-minute intervals and is taken in as power data. afterwards,
As shown after point B in the figure, the power data d ₂ and 12
Comparing the power data d ₁₂ after minute, it is determined that the difference Δd of the two power data metal layer is present in the case was less than predetermined value D, turn off 22 and simultaneously sounds the alarm. Since the interval for measuring the power data and the time interval between the two power data to be compared can be arbitrarily set, the optimum interval is considered in consideration of various conditions such as the capacity of the furnace 2 and the time until the raw material is completely dissolved. The interval may be set.

As described above, according to the metal layer detecting apparatus 21 of the above-described embodiment, the power supplied to the furnace 2 connected to the medium frequency induction melting furnace 23 is measured at predetermined time intervals. A detection unit that captures as power data, and compares the power data at a predetermined time among the power data output from the detection unit with the power data after a predetermined time has elapsed from the predetermined time. And a determination unit 25 that determines that a metal layer is present when the difference between them is equal to or less than a preset value. Therefore, it is possible to quickly detect a metal layer generated above the molten metal, and This prevents the occurrence of problems such as being caught in the melt, the solidification of the raw material above the melt to form an alloy layer, and the oxide covering the surface of the melt. Therefore, unmelting of the raw material, bumping of the molten metal, melting of the furnace material, and the like can be prevented.

In the above embodiment, the melting furnace is a medium-frequency induction melting furnace 23. However, this melting furnace may be any electric furnace, other than the medium-frequency induction melting furnace 23.
For example, it is needless to say that the present invention can be applied to a high frequency or low frequency induction melting furnace. Also, this medium frequency induction melting furnace 2
Although 3 uses a magnetic triple frequency converter, the present invention is not limited to the above-described embodiment. For example, a device using a thyristor frequency converter can provide the same effect.

In the above embodiment, the power data is fetched as measurement data, and the presence or absence of the metal layer is determined based on the fetched power data. However, in addition to the power data, current data or voltage data is measured. Of course, the presence or absence of the metal layer may be determined based on the captured current data or voltage data.

The metal layer detecting device 21 detects a metal layer generated above the molten metal during melting, but the raw material is completely melted into the molten metal and the temperature of the molten metal is rising. In the same case, since the power is constant, the time interval between the two power data to be measured and compared is determined by various conditions such as the amount of raw material to be melted, the timing, and the method of supplying power at the initial stage and during melting. By taking this into consideration, it is possible to accurately detect an excessive temperature rise of the molten metal.

[0017]

As described above, according to the apparatus for detecting a metal layer of a melting furnace of the present invention, the electric power supplied to the melting furnace,
Detecting means for measuring at least one of the current or the voltage at a preset time interval, and capturing the measured data as measurement data;
The measurement data output from the detection means is compared with measurement data at a predetermined time and measurement data after a predetermined time has elapsed from the predetermined time, and a difference between the measurement data is equal to or less than a predetermined value. In such a case, a determination means for determining that a metal layer is present is provided, so that a metal layer generated above the molten metal can be quickly detected, and the raw material can be caught above the molten metal, or the raw material can be detected above the molten metal. Problems such as solidification to form an alloy layer and the oxide covering the surface of the molten metal can be prevented. Therefore, unmelting of the raw material, bumping of the molten metal, and melting of the furnace material can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an apparatus for detecting a metal layer of a melting furnace according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation principle of the metal layer detecting device of the melting furnace according to one embodiment of the present invention.

FIG. 3 is a diagram showing a method of capturing and determining power data of the metal layer detecting device of the melting furnace according to one embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing an example of a defect in a conventional melting furnace.

FIG. 5 is a longitudinal sectional view showing an example of a defect of a conventional melting furnace.

FIG. 6 is a longitudinal sectional view showing an example of a defect of a conventional melting furnace.

[Explanation of symbols]

 Reference Signs List 21 metal layer detecting device 23 medium frequency induction melting furnace 24 detecting unit (detecting means) 25 determining unit (determining means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F27B 14/20 F27B 14/06 F27D 21/00 H01B 6/02

Claims (1)

(57) [Claims] 1. A device for detecting a metal layer generated above a molten metal being melted by a melting furnace, wherein at least one of electric power, current or voltage supplied to the melting furnace is set for a predetermined time. Detecting means that measures at intervals and captures as measurement data, and compares the measurement data at a predetermined time among the measurement data output from the detection means with the measurement data after a lapse of a predetermined time from the predetermined time, Determining means for determining that a metal layer is present when the difference between the measurement data is equal to or smaller than a preset value.