JPH03110387A - Level detector for melted metal - Google Patents

Abstract

PURPOSE:To provide a level detector for melted metal capable of detecting the malfunction of an electrode, by providing changeover switch means for switching to form specific closed circuit at the times of detecting a liquid surface level and a malfunction. CONSTITUTION:When electrodes 21, 22 and 23, 24 of a level detector 10 are set in a level detection mode, an operator switches a changeover switch 41 to a level detection mode side. Here, when the liquid surface level of melted aluminum 1 in a melting furnace 2 is raised to a first liquid surface detection level 3, a closed circuit of a lead 81, an electrode 21a, the aluminum 1, an electrode 22a and a lead 83 is formed, and conducted to light a lamp 62. Accordingly, the operator stops melting, and discharges the aluminum 1 in the furnace 2. If the aluminum 1 is raised to a second liquid surface detection level 4, a closed circuit of a lead 85, an electrode 23a (or the lead 81 and the electrode 21a), the aluminum 1, an electrode 24a, and a lead 87 is formed, in addition to the above closed circuit, and conducted to light lamps 62, 64, thereby notifying a malfunction to the operator.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a level detection device for detecting the level of molten metal contained in a container, and in particular for detecting abnormalities such as wear and poor connection of the detection electrode. This invention relates to a molten metal level detection device that makes it possible to detect the level of molten metal.

[Prior art]

Usually, a melting furnace that melts base metals such as cast iron and aluminum to produce molten metal is equipped with a level detection device for detecting the liquid level of the molten metal in the melting furnace.

As shown in FIG. 4, the level detection device 100 has three connection terminals 102 to 104 fixedly disposed above a DC power supply 101 and a melting furnace 110, and each connection terminal 102 to 104.
The melting furnace 104 is composed of rod-shaped electrodes 105 to 107 that are attached to the upper ends of the melting furnace 104 and suspended within the melting furnace 110.

The connection terminal 102 is connected to the positive terminal of the DC power supply 101, the connection terminal 103 is connected to the negative terminal of the DC power supply 101 through the lamp 108, and the connection terminal 104 is connected to the negative terminal of the DC power supply 101 through the lamp 109. It is connected.

On the other hand, the lower end of the electrode 105 is immersed in the molten metal 111, and the lower end of the electrode 106 is located above the lower end of the electrode 105, as shown by the solid line in FIG. Set first detection level 1
12, and the lower end of the electrode 107 is located at a second detection level 113, which is the liquid level at which the molten metal 111 has abnormally risen above the lower end of the detection electrode 106, as shown by the dashed line in FIG. ing.

The lamps 108 and 109 are provided on, for example, an operation panel that can be visually recognized by an operator who operates and monitors the melting furnace 110.

By providing the level detection device 100 in this way,
When the molten metal 111 rises to the first detection level 112, the electrodes 105 and 106 are energized through the molten metal 111, and the lamp 108 is turned on to notify the operator. Further, when the molten metal 111 rises to the second detection level 113, the electrode 105 and the electrode 10
7 is energized, and in addition to lighting the lamp 108, the lamp 109 is turned on.
is lit to notify the operator of an abnormality in the level of the molten metal 111.

For reference, Japanese Patent Application Laid-Open No. 113723/1983 discloses a level sensor that provides a movable thermocouple electrode that can move up and down in addition to a plurality of fixed thermocouple electrodes to improve the accuracy of level detection of molten metal. The detection device is described.

[Problem to be solved by the invention]

In the level detection device 100 described above, there is a problem that when the electrodes 105 and 106 that contact the high temperature molten metal 111 are worn out and shortened, the first detection level 112 cannot be detected accurately.

Further, the electrodes 105 to 107 and the respective connection terminals 102
104 is disconnected, there is a problem that the liquid level of the molten metal 111 cannot be detected.

An object of the present invention is to provide a molten metal level detection device capable of detecting an abnormality in an electrode.

[Means for Solving the Problems] The molten metal level detection device of the present invention is a level detection device for detecting the liquid level of molten metal contained in a container, in which the lower end is set at the liquid level detection level. a first electrode connected to the first energizing circuit; a second electrode having a lower end set at the liquid level detection level and connected to the second energizing circuit; and a second electrode connected to the lower end of the first electrode. 1 abnormality detection circuit, a second abnormality detection circuit connected to the lower end of the second electrode, and a first energization circuit, the first electrode, the molten metal, the second electrode, and the second energization when detecting the liquid level. When an abnormality is detected, the first energized circuit and the first
A changeover switch means is provided for switching the circuit so as to configure a closed circuit consisting of the abnormality detection circuit or a closed circuit consisting of the second energizing circuit and the second abnormality detection circuit.

[Function] In the molten metal level detection device of the present invention, when detecting the level of the molten metal in the container, the first energizing circuit, the first electrode, the second electrode, and the second energizing circuit are connected via the molten metal. The circuit is switched by means of a changeover switch so that a closed circuit is formed.

At this time, if the liquid level of the molten metal contained in the container is at a low level below the upper ends of the first and second electrodes, the closed circuit is not formed and no current is applied.

When the liquid level of the molten metal rises to a predetermined liquid level detection level at which the lower ends of the first and second electrodes are located, the closed circuit is formed through the molten metal and electricity is supplied.

Therefore, by providing a lamp or a buzzer in the closed circuit, it is possible to detect that the molten metal has reached a predetermined liquid level detection level by lighting the lamp or making a buzzer sound.

On the other hand, when detecting the presence or absence of an abnormality in the electrode, a closed circuit consisting of a first energizing circuit and a first abnormality detection circuit or a closed circuit consisting of a second energizing circuit and a second abnormality detection circuit is configured. The circuit is switched by means of a changeover switch.

If the first energizing circuit is disconnected, there is a poor connection between the first energizing circuit and the first electrode, or the lower end of the first electrode is worn out, the first energizing circuit and the first abnormality detection circuit A closed circuit is not formed and the current does not turn on. Similarly, if the second energizing circuit is disconnected, there is a poor connection between the second energizing circuit and the second electrode, or the lower end of the second electrode is worn out, the second energizing circuit and second abnormality detection A closed circuit with the service circuit is not formed and no current is applied.

Therefore, by providing a lamp or a buzzer in each closed circuit, the operator can detect whether or not there is an abnormality in each electrode by lighting the lamp or sounding the buzzer.

〔Effect of the invention〕

According to the molten metal level detection device of the present invention, as explained in the [Function] section above, abnormalities such as wear and tear of each electrode, disconnection of each current-carrying circuit, and poor connection between each electrode and each current-carrying circuit can be detected. Detection can be performed with a simple switching operation of the switch means. In addition, the liquid level of the molten metal can always be accurately detected.

In addition, since the lower end of the first electrode is set at the liquid level detection level, wear and tear on the first electrode can be reduced.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, the present invention is applied to a level detection device 10 installed in a melting furnace 2 for making molten aluminum 1, as shown in FIG.

The level detection bag W10 has a pair of V-shaped electrodes 21 and 22 for detecting a first liquid level detection level 3, and a second liquid level detection level 4 above the first liquid level detection level 3. A pair of V-shaped electrodes 23 and 24 for detection, and electrodes 21 and 22
and an electromagnetic switch 30 for switching the electrodes 23 and 24 between a level detection mode for detecting the liquid level of the molten aluminum 1 and an abnormality detection mode for detecting abnormalities in the electrodes and circuits.
, a control box 40 for operating and monitoring the melting furnace 2 , connection terminals 51 - 58 for attaching the electrodes 21 - 24 respectively, and conductive wires 81 - for connecting the connection terminals 51 - 58 and the electromagnetic switching device 30 It consists of 88 etc.

The electrode 21 consists of an electrode 21a of a predetermined length and an abnormality detection electrode 21b, and as shown in FIG.
The upper end portions of are attached to connection terminals 51 and 52, respectively.

The electrode 22 consists of an electrode 22a of a predetermined length and an abnormality detection electrode 22b, the electrode 22a and the electrode 22b are joined at their lower ends, and the upper ends of the electrode 22a and the electrode 22b are attached to connection terminals 53 and 54, respectively. ing.

The electrodes 21 and 22 are suspended in the melting furnace 2, and the electrodes 21 and 22 are suspended in the melting furnace 2.
The lower end portions of 1 and 22 are located at a first liquid level detection level 3 where the molten aluminum 1 can be tapped, as shown by the solid line in FIG.

The electrode 23 is composed of an electrode 23a of a predetermined length and an abnormality detection electrode 23b, the electrode 23a and the electrode 23b are joined at their lower ends, and the upper ends of the electrode 23a and the electrode 23b are attached to connection terminals 55 and 56, respectively. ing.

The electrode 24 consists of an electrode 24a of a predetermined length and an abnormality detection electrode 24b, the electrode 24a and the electrode 24b are joined at their lower ends, and the upper ends of the electrode 24a and the electrode 24b are attached to connection terminals 57 and 58, respectively. ing.

The electrodes 23 and 24 are suspended in the melting furnace 2, and the electrodes 23 and 24 are suspended in the melting furnace 2.
The lower ends of 3 and 24 are located at the second liquid level detection level 4 when the molten aluminum 1 rises abnormally, as shown by the dashed line in FIG.

The electromagnetic switching device 30 is a pair of single-pole double-throw electromagnetic switching devices 3.
1 and 32, the electromagnetic switch 31 has a common terminal 31a and switching terminals 31b and 31c, the electromagnetic switch 32 has a common terminal 32a and switching terminals 32b and 32c, and the common terminal 31a is connected to the control box 40. It is connected to the positive terminal of the DC power source 40a, and the common terminal 32a is connected to the positive terminal of the DC power source 40a.
It is connected to the negative terminal of a.

Next, the connection terminals 51 to 58 and the electromagnetic switching devices 31 and 32 are connected to each other.
We will explain the connection with.

The connection terminal 51 is connected to the switching terminal 31b via a conductor 81, and the connection terminal 52 is connected to a lamp 61 interposed in series.
and the switching terminal 3 via a conductor 82 having an electromagnetic switch 71.
2c, the connecting terminal 53 is connected to the switching terminal 32b via a conductor 83 having a lamp 62, and the connecting terminal 54
is connected to the switching terminal 3 via a conductor 84 having an electromagnetic switch 72.
1c, the connecting terminal 55 is connected to the switching terminal 31b via a conducting wire 85, and the connecting terminal 56 is connected to the switching terminal 32c via a conducting wire 86 having a lamp 63 and an electromagnetic switch 73 interposed in series. and the connection terminal 57 is connected to the lamp 6.
The connecting terminal 5 is connected to the switching terminal 32b via a conducting wire 87 having an electromagnetic switch 74, and the connecting terminal 5 is connected to the switching terminal 31C via a conducting wire 88 having an electromagnetic switch 74.

The lamps 61 to 64 are mounted on the display panel of the control box 40 so that they can be viewed by the operator.

The control box 40 includes a programmable sequence controller equipped with a timer, and a preset sequence is programmed into the sequence controller.

The electromagnetic switches 31 and 32 and the electromagnetic switches 71 to 74 can be switched by a switching signal from a control box 40, and the control box 40 is equipped with a sequence controller that can be switched between a level detection mode and an abnormality detection mode. A changeover switch 41 for switching to
is provided.

The operation of the level detection device 10 configured as above will be explained.

When setting the electrodes 21 and 22 and electrodes 23 and 24 to the level detection mode, the operator
1 to level detection mode. At this time, a switching signal from the control box 40 causes the electromagnetic switching
The common terminal 31a and the switching terminal 31b of the electromagnetic switch 32 are closed, the common terminal 32a and the switching terminal 32b of the electromagnetic switch 32 are closed, and the electromagnetic switches 71 to 74 are opened.

By setting the electrodes 21 and 22 and the electrodes 23 and 24 to the level detection mode in this way, the melting of the aluminum ingot in the melting furnace 2 progresses and the liquid level of the molten aluminum 1 reaches the first liquid level detection level 3. As it rises, the conductor 81
A closed circuit consisting of the electrode 21a, the molten aluminum l, the electrode 22a, and the conductor 83 is formed, and the lamp 62 is energized.
lights up. After confirming that the lamp 62 is lit, the operator stops melting and taps the molten aluminum 1 in the melting furnace 2.

In addition, in the unlikely event that the molten aluminum l reaches the second liquid level detection level 4,
When the temperature rises to 1, a closed circuit consisting of the conducting wire 85, the electrode 23a (or the conducting wire 81 and the electrode 21a), the molten aluminum 1, the electrode 24a, and the conducting wire 87 is formed in addition to the above-mentioned closed circuit, and the lamp 62 is energized. In addition, a lamp 64 is lit to notify the operator of the abnormality.

When setting the electrodes 21 and 22 and the electrodes 23 and 24 to the abnormality detection mode, for example, after the molten aluminum 1 is tapped from the melting furnace 2, the changeover switch 41 is switched to the abnormality detection mode side.

When set to the abnormality detection mode, the electromagnetic switches 31 and 32 and the electromagnetic switches 71 to 74 are switched according to the following sequence by a switching signal from the control box 40.

First, a switching signal is output from the control box 40 to the electromagnetic switch 32 and the electromagnetic switch 71, and the electromagnetic switch 32
The common terminal 32a and the switching terminal 32C are closed, and the electromagnetic switch 71 is closed.

In addition, the electromagnetic switch 31 has a common terminal 31a and a switching terminal 31b.
is closed, and the electromagnetic switches 72 to 74 are opened.

When the electrode 21 is normal, a closed circuit consisting of the conductor 81, the electrode 21a, the abnormality detection electrode 21b, and the conductor 82 is formed and the lamp 61 lights up, so the operator can confirm that the electrode 21 is normal. can be confirmed.

On the other hand, when the electrode 21 is abnormal, that is, when the connection between the electrode 21a and the connecting terminal 51 is disconnected, or when the joint between the electrode 21a and the abnormality detection electrode 21b is worn out due to contact with the hot molten aluminum 1. If the junction is separated as shown in Figure 3, the above closed circuit will not be formed and the lamp 61 will not light up, so the operator must
1 abnormality can be confirmed.

Next, from the control box 40, the electromagnetic switch 71
A switching signal is output to 73, and the electromagnetic switch 71 is opened and the electromagnetic switch 73 is closed. In addition, electromagnetic switching device 3
1 and 32 are in the same state as above, and the electromagnetic switch 72 and
74 are open.

When the electrode 23 is normal, a closed circuit consisting of the conductor 85, the electrode 23a, the abnormality detection electrode 23b, and the conductor 86 is formed and the lamp 63 lights up, so the operator can confirm that the electrode 23 is normal. can be confirmed.

On the other hand, as in the case of the electrode 21, when the electrode 23 is abnormal, the closed circuit is not formed and the lamp 63 does not light up, so that the operator can confirm whether the electrode 23 is abnormal.

Next, from the control box 40, the electromagnetic switch 31 and
32 and the electromagnetic switches 72 and 73, the common terminal 31a and the switching terminal 31c are closed, and the common terminal 32
a and the switching terminal 32b are closed, the electromagnetic switch 72 is closed, and the electromagnetic switch 73 is opened. In addition, electromagnetic switch 71/7
4 is in the open state.

When the electrode 22 is normal, a closed circuit consisting of the conductor 84, the abnormality detection electrode 22b, the electrode 22a, and the conductor 83 is formed and the lamp 62 lights up, so the operator can confirm that the electrode 22 is normal. can be confirmed.

On the other hand, as in the case of the electrode 21, when the electrode 22 is abnormal, the closed circuit is not formed and the lamp 62 does not light up, so that the operator can confirm whether the electrode 22 is abnormal.

Next, from the control box 40, the electromagnetic switch 72
A switching signal is output to 74, and the electromagnetic switching device 72 is opened.
The electromagnetic switch 74 is closed. In addition, electromagnetic switching devices 31 and 32
is in the same state as above, and the electromagnetic switches 71 and 73 are in the open state.

When the electrode 24 is normal, a closed circuit consisting of the conductive wire 88, the abnormality detection electrode 24b, the electrode 24a, and the conductive wire 87 is formed and the lamp 64 lights up, allowing the operator to confirm that the electrode 24 is normal. can be confirmed.

On the other hand, as in the case of the electrode 21, when the electrode 24 is abnormal, the closed circuit is not formed and the lamp 64 does not light up, so that the operator can confirm whether the electrode 24 is abnormal.

In this way, the confirmation of the presence or absence of abnormalities in the electrodes 21, 22 and the electrodes 23, 24 is completed, and the electrodes 21, 22 and the electrodes 2
When it is confirmed that there is no abnormality in terminals 3 and 24, and the operator switches the changeover switch 41 to the level detection mode, a switching signal is output from the control box 40 to the electromagnetic switching device 31 and the electromagnetic switching device 74, and the common terminal 31a and the switching signal are output. The terminal 31b is closed, the electromagnetic switch 74 is opened, and the electrode 21
・Set 22 and electrodes 23 and 24 to level detection mode.

On the other hand, if an abnormality is confirmed in the electrodes 21 and 22 and the electrodes 23 and 24, the operator replaces the electrodes or repairs the electrical system.

In this way, abnormalities such as wear or poor connection of the electrodes 21 and 22 and the electrodes 23 and 24 can be detected with a simple operation. Furthermore, the liquid level of the molten aluminum 1 in the melting furnace 2 can always be accurately detected.

It goes without saying that the level detection device 10 can be used to detect not only the liquid level of molten aluminum l, but also the liquid level of various molten metals such as cast iron and aluminum alloy. In addition, the electrodes 21 and 22 and the electrodes 23 and 24
is formed into a V-shape by joining, but it may be integrally formed into a V-shape.

Furthermore, it is also possible to use a buzzer or an ammeter instead of the lamps 61 to 64. Note that the lower end of the electrode 21 may be set at a level lower than the first liquid level detection level 3,
The electrode 23 is not necessarily required and may be omitted.

[Brief explanation of drawings]

1 to 3 show embodiments of the present invention. FIG. 1 is a block diagram of the level detection device, FIG. 2 is an enlarged view of the lower end of the electrode, and FIG. 3 is an enlarged view of the lower end of the electrode. Enlarged view showing wear and tear,
FIG. 4 is a block diagram of a level detection device according to the prior art. ■...Aluminum molten metal, 2...Melting furnace, 3...1st
Liquid level detection level, 4...Second liquid level detection level, 2
1a to 24a... Electrode, 21b to 24b... Electrode for abnormality detection, 31, 32... Electromagnetic switching device, 40...
Control box, 81-88... conductor.

Claims (1)

[Claims] (1) In a level detection device that detects the liquid level of molten metal contained in a container, a first electrode whose lower end is set at the liquid level detection level and connected to the first energizing circuit; a second electrode set to a liquid level detection level and connected to a second energizing circuit; a first abnormality detection circuit connected to the lower end of the first electrode; and a first abnormality detection circuit connected to the lower end of the second electrode. When detecting the liquid level, the circuit forms a closed circuit consisting of the first energizing circuit, the first electrode, the molten metal, the second electrode, and the second energizing circuit, while when detecting an abnormality, the first energizing circuit The present invention is characterized by being provided with a changeover switch means for switching the circuit so as to configure a closed circuit consisting of the circuit and the first abnormality detection circuit or a closed circuit consisting of the second energizing circuit and the second abnormality detection circuit. Molten metal level detection device.