JPH07225105A - Device for discontinuously detecting thickness of layer on metal fused body - Google Patents

Abstract

PURPOSE: To secure non-continuous detection of the thickness of an upper layer on a metal melt with high reliability but a scant cost. CONSTITUTION: A sensor device comprises at least two sensors 5, 6, a measuring signal for a distance from the metal melt 1 to a first electromagnetic sensor 5 using it is generated, a signal is generated at a predetermined distance from a second layer using a second sensor 6 and the measuring signal from the first sensor is evaluated by using an evaluating device when the second sensor 6 generates the signal showing the predetermined distance from the second layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for discontinuously detecting the thickness of a layer on a metal melt, using a sensor device movable in the direction of the layer. The sensor device is connected to at least one evaluation device and emits a characteristic signal for each layer to be detected.

[0002]

BACKGROUND OF THE INVENTION Generally known equipment as described above is used in the production of metals. Due to the manufacturing process, i.e. in the various cleaning processes of the metal melt, the non-metal constituents contained in said metal melt are collected on the surface of the melt, where they are influenced by the atmosphere and excessive heat. Forms a viscous solid slag layer that protects against loss.

Various devices are known for detecting the slag layer thickness upon which another process step of metal production depends.

From DE-A-364 1987 is known a device for measuring the height of a slag of a metal melt, using a support which is designed as a lancet. The support includes a hum detector connected to the antenna, which detects the power hum near the antenna. When the lancet is immersed in the metal melt, a hum detector detects the air / slag transition and an inductive sensor signals that the boundary layer between the slag and the metal melt has been reached. In order to determine the slag thickness from this, the signal obtained as described above must additionally be associated with a continuous distance measurement. Coupling this device to an external distance measuring device impairs the mobility of the device, making it particularly difficult to implement as a manual lancet.

From DE 38 32 763 A1 is known a device for detecting the level of a slag boundary layer of a metal melt, which device is based on the principle of detecting impedance changes via an impedance circuit.
Such an impedance circuit is connected to the oscillator and the measuring rod or the measuring rod feed cable.

The oscillator operates at a frequency different from the power supply frequency. The impedance change is detected using a synchronous detector. When the output signal of the sync detector passes through the circuit corresponding to the predetermined corresponding interface, the corresponding threshold circuit forms a signal. This signal indicates that the measuring rod is present at a certain distance from the corresponding interface. Once again, the slug thickness can only be detected by additionally associating the threshold circuit signal with a continuous distance measurement. In addition to the above-mentioned drawbacks with regard to the mobility problems of this device, this device also requires a particularly precise constant velocity. This is because the quality of impedance change is significantly affected by the distance and the velocity.

From JP 61-212702 A there is known a device for detecting the thickness of a slag, which is constructed as a lancet. In this device, the electrode at the tip of the lancet is immersed in the metal melt. At that time, the impedance changes between the electrode and the melt container in the air / slag transition region and the slag / metal melt transition region. Such impedance changes are detected by a threshold circuit, but also impedance changes must be additionally associated with the continuous distance measurement in order to detect the slug thickness.

From EP-A-0421828 is known a method for continuously measuring the thickness of a liquid slag layer on the surface of a metal melt. Here, the level sensor fixedly installed continuously measures the distance to the surface of the melt. The isothermal block is then held in the powder / liquid slag transition using a regulated tracking control device. In this case, in order to obtain the slag density from the difference between the results of the two measuring devices, the tracking control device needs a distance measuring device for detecting the position of the isothermal block. A continuous individual measurement with a configuration based on such a method takes longer than a discontinuous measurement and accelerates the wear of the isothermal block. Furthermore, the isothermal block requires a costly moving device (displacement device) using a distance measuring device and a control device.

The known devices and methods described above have common drawbacks. In other words, a mobile device that is expensive to measure,
Furthermore, a device that can detect the moving distance with high reliability is required. Therefore, as long as there is a corresponding mobile device, such a device must be additionally equipped with a travel distance detection device.

Further, from Japanese Patent Laid-Open No. 2-247539,
Devices for detecting the thickness of the slag are already known, but this device does not necessarily require a distance measuring device.
This device includes one lancet, which is provided with a nozzle at the top of the lancet, through which the noble gas flows. When the dynamic pressure is detected each time using the pressure sensor, the dynamic pressure initially rises gently at the air / slag transition and rises sharply at the slag / liquid metal transition. The thickness of the slag is detected from the difference in pressure from entering the slag to entering the metal melt, taking the density of the slag into consideration. However, such a measuring principle can only be used with viscous slags. Even in the case of viscous slag, the dynamic pressure is not only affected by the density, but also by the immersion depth and the varying viscosity which can reach from liquid to solid state in the slag layer. Another drawback of this device is as follows. That is, the transition portion cannot be detected accurately, and it is actually impossible to measure a thin slag layer. If no distance measuring device is used, the dipping speed must be kept low and constant. Otherwise, in some cases the transition between the slag and the metal melt cannot be identified.

[0011]

SUMMARY OF THE INVENTION The object of the invention is to provide a device of the type mentioned at the outset in order to ensure reliable detection of the layer thickness at a small device cost. That is. In particular, the accuracy of the layer measurement should be independent of the mobile device and the travel distance detection device.

[0012]

SUMMARY OF THE INVENTION The above-mentioned problems are connected to at least one evaluation device according to the invention, which is movable in the direction of the layers and which emits a characteristic signal for each layer to be detected. Starting from the device for discontinuously detecting the thickness of the layer above the metal melt using the device,
With the aid of the sensor device, at least one signal is generated as a distance signal of the electromagnetic sensor with respect to one surface of the layer boundary surface, where a clear relationship between signal and distance is established in the measuring area. , At least one further signal is generated for each layer to be detected, at least at a certain distance from the sensor device to the layer to be detected in each case being distinct between the signal and the distance. The above relationship is established, and is solved by obtaining the layer thickness in the evaluation device from the above signal.

The sensor device according to the invention makes it possible to measure the thickness of the slag layer on the metal melt without taking into account generally unknown travel distances or travel speeds. This is possible with particular advantage in the following configuration. That is, at least one sensor is configured as an electromagnetic sensor, which sensor produces a distance signal for one of the layer boundary surfaces. When one of the layers is reached, the distance signal is evaluated by the evaluation device at the time when the switch signal indicates that another layer has been reached, together with another sensor that emits a simple signal, eg a switch signal. By doing so, it is possible to directly measure the thickness.

The sensor device comprises similar or different sensors having the same or different operating principles.

In a particularly advantageous embodiment of the invention, the sensor arrangement comprises at least two sensors, the first electromagnetic sensor being used to generate a signal for determining the distance from the metal melt to the sensor. A signal is generated at a predetermined distance from the layer using the second sensor. When the second sensor produces a signal indicative of the predetermined distance from the layer, the signal of the first sensor is evaluated using an evaluation device.

As the sensor device approaches the bed, it can plunge into the bed.

If the sensor device, which is preferably moved vertically with respect to the metal melt, moves with respect to the metal melt at an angle deviated from the vertical, the angular deviation is detected and is simply associated with the signal correction. Can be made.

In another embodiment of the invention, the sensor is configured as an acceleration sensor, said sensor comprising:
A signal is emitted when the sensor device reaches the upper layer.

According to such an embodiment, it is possible to detect whether or not the layer has reached the layer in a layer having a wide viscosity range.

In order to detect a relatively thin liquid medium on the basis of its electrical properties, it is advantageous if all the sensors are embodied as electromagnetic sensors.

In order to make the device according to the invention independent of external distance measurements, it is possible to configure the device as a hand-held lancet so that the sensor device can be moved manually in the layer direction. Such an embodiment is particularly suitable for measuring situations, such as test measurements, in tight spaces or where the cost of the mobile device is high.

Further, the embodiment of the present invention has a configuration in which the sensor device is attached to the lancet as a replaceable unit.

According to such an embodiment, the sensor device provided for measuring the layer thickness is replaced by another sensor, for example to detect another measurement value or to easily replace a defective sensor device. It can be easily replaced with a device.

It is also within the scope of the invention to couple the device for detecting at least one of the further measured values to the device according to the invention in the lancet or as part of a protective sleeve.

[0025]

The present invention will now be described in detail with reference to the drawings based on an embodiment.

FIG. 1 is a schematic diagram of a sensor device according to the present invention. This sensor device has α = 9 for the metal melt 1.
It can be moved at an angle of 0 °, that is, vertically. The metal melt 1 is covered with the slag layer 2, and the thickness of the slag layer 2 must be detected. The device comprises a lancet 3, shown cutaway, which is housed in a protective tube 4, which is also shown cutaway.
At the far end of the lancet 3, the first sensor 5 and the second sensor 5
Sensor 6 is arranged side by side so as to be flush with the end of the lancet 3.

The first sensor 5 is configured as an electromagnetic sensor and is connected to the first pretreatment device 8 via a conductor 7. The pretreatment device 8 is connected via a conductor 9 to an evaluation device (not shown). A first signal is generated at the first sensor 5. With this signal,
The respective distance from the metal melt 1 to the first sensor 5 can be determined.

The second sensor 6 is connected to the second sensor 6 via the conductor 10.
Is connected to the pretreatment device 11 and is connected to the evaluation device (not shown) via the lead wire 12. Second
The second signal is generated only at a defined distance from the slag layer 2 using the sensor 6 of.

FIG. 2 shows a waveform diagram for explaining the signal evaluation of the sensor device according to FIG. As shown in FIG. 2, when the second sensor 6 produces a second signal indicative of the defined distance from the slag layer 2, the first signal of the first sensor 5 is evaluated. Therefore, the slag layer thickness can be derived from the characteristic signal for the slag layer 2 to be evaluated.

Other detection methods are known to the person skilled in the art when the signal is recorded and stored during the measurement and is not evaluated until the end of the measurement. That is, it is also possible advantageously to measure layer thicknesses which are thicker than the measuring area of the first sensor.

[Brief description of drawings]

1 shows a schematic view of a sensor device according to the invention.

2 shows a waveform diagram for explaining the signal evaluation of the sensor device according to FIG.

[Explanation of symbols]

 1 Metal Melt 2 Slag Layer 3 Lancet 4 Protective Tube 5 First Sensor 6 Second Sensor 7 Conductive Wire 8 Pretreatment Device 9 Pretreatment Device 10 Conductive Wire

Claims (6)

[Claims] 1. Above the metal melt using a sensor device which is connected to at least one evaluation device and which emits a characteristic signal for each layer to be detected and is movable in the direction of the layer. In a device for the non-continuous detection of the layer thickness of a layer, at least one signal is generated as a distance signal of an electromagnetic sensor with respect to one of the layer boundary planes, using a sensor device, , There is a clear relationship between signal and distance in the measurement area, at least another signal is generated for each layer to be detected, from the sensor device to the layer to be detected each time. The thickness of the layer above the metal melt, characterized in that there is an explicit relationship between the signal and the distance in at least one distance of Detected non-continuously Because of the device. 2. The sensor device comprises at least two sensors (5, 6), the distance from the metal melt (1) to the sensor (5) being measured using a first electromagnetic sensor (5). Is generated and a signal is generated at a predetermined distance from the layer (2) using the second sensor (6), the second sensor (6) indicating a predetermined distance from the layer (2). The layer thickness detection device according to claim 1, characterized in that, when a signal is generated, the signal of the first sensor (5) is evaluated using an evaluation device. 3. The sensor (5 or 6) is embodied as an acceleration sensor, whereby a signal is emitted when the sensor device contacts the uppermost layer (2). Alternatively, the layer thickness detecting device according to item 2. 4. Layer thickness detection device according to claim 1, characterized in that the two sensors (5, 6) are configured as electromagnetic sensors. 5. The layer thickness detection device according to claim 1, wherein the sensor device is manually movable in the direction of the layer. 6. The layer thickness detection device according to claim 1, wherein the sensor device is mounted on the lancet as a replaceable device.