JP3513381B2 - Method and apparatus for detecting liquid level in mold - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a liquid level in a mold for detecting the liquid level of the molten metal in a mold in continuous casting of molten metal such as steel.

[0002]

2. Description of the Related Art In continuous casting of molten metal such as steel,
Molten metal is continuously cast by supplying molten metal into a mold from a molten metal container such as a tundish, and pulling out a slab that is being solidified below the mold. The liquid level of the molten metal in the mold is kept constant by balancing the feeding rate of the molten metal fed from above and the withdrawal rate of the slab to be pulled downward. In order to keep the liquid level in the mold constant, the liquid level in the mold is constantly monitored, and when the liquid level fluctuates, it is melted by a molten metal supply amount adjusting device such as a stopper in the tundish. To adjust the metal feed rate,
Alternatively, the demand-supply balance is adjusted by adjusting the withdrawal speed of the slab. Recently, various liquid level detecting methods and devices for automatically monitoring the liquid level in the mold have been put into practical use.

A plurality of temperature detectors, specifically thermocouples, are embedded in the mold at positions of different heights, and the liquid level is determined by the relative relationship between the temperatures in the mold detected by the plurality of temperature detectors. Methods for detecting levels are known. Hereinafter, the detection method by this method is referred to as a temperature detection method. It has the feature that the absolute value of the liquid level can be measured with high accuracy. On the other hand, since the temperature detection end will be installed at a position with a certain depth from the surface where the mold is in contact with the molten metal, the fluctuation of the detected temperature is delayed with respect to the fluctuation of the liquid level. Therefore, there is a problem that the reaction to the rapid liquid level change is slow. Also, when adopting the mold vibration that vibrates the continuous casting mold vertically with a constant cycle, the temperature detector arranged in the mold also vibrates together with the mold, so the temperature detection value has a fluctuation of the same cycle as the mold vibration. Have the problem of being.

A γ-ray generation source is arranged on one side of the mold and a γ-ray detector is arranged on the other side, and the level of liquid level changes from the change in the γ-ray transmittance caused by the molten metal in the mold blocking γ-rays. There are known methods for detecting. Hereinafter, this method is referred to as a γ-ray method. It can detect relatively rapidly even when the liquid level in the mold changes rapidly, and the running cost is low.
On the other hand, there is a problem that the initial investment is large and the handling should be careful. Also, if molten metal splashes or powder bears that block γ-rays adhere to the mold, the γ-ray detection value will fluctuate due to the effects of these deposits, and a liquid level value different from the actual liquid level of the molten metal will appear. There is a problem of outputting, so-called drift phenomenon.

An AC signal transmitting coil and a receiving coil are installed above the liquid level in the mold. When the coil and the liquid level are close to each other, a vortex is generated in the molten metal and the detection value of the receiving coil fluctuates. There is known a method of detecting the liquid surface level by utilizing the phenomenon. Hereinafter, this method is referred to as the eddy current method. It is most commonly used in large-section slab continuous casting equipment and bloom continuous casting equipment because it can handle sudden changes in liquid level and is easy to handle. On the other hand, because the coil must be installed very close to the molten metal,
If the liquid level of the molten metal rapidly rises due to a trouble, the heat easily causes the coil to be damaged, and the running cost is not low. Further, in the billet continuous casting device having a small cross section, the eddy current sensor can be installed only near the wall of the mold, and if the sensor is close to the wall of the mold, the sensor is affected and the detection sensitivity decreases. .

An industrial television camera (IT
A method is known in which the liquid level is detected by observing in V) and image-processing the observation result. Hereinafter, this method is referred to as the ITV method. Also, irradiate the laser light on the liquid surface in the mold,
A method of detecting the reflected light and detecting the liquid surface level is known. Hereinafter, this method is referred to as a laser method. IT
In both the V method and the laser method, the reaction speed with respect to the liquid level fluctuation is very fast, but when the liquid surface in the mold is covered with powder during powder casting, the surface to be detected is just the powder upper surface position, so the powder thickness is If it is unknown, there is a problem that the absolute value of the liquid level cannot be detected.

[0007]

As described above, all of the conventionally known methods for detecting the liquid level in a mold have advantages and disadvantages, and detection methods that do not have disadvantages in all respects. There is no way. An object of the present invention is to realize a method for detecting a liquid level in a mold that has a fast response speed to a rapid change in liquid level and does not cause a drift phenomenon at low running cost.

In particular, even when the method using the eddy current method cannot be adopted because the surface of the molten metal in the mold is narrow, as in the small-section billet continuous casting apparatus, the response speed to the rapid fluctuation of the liquid level is high. It is an object of the present invention to realize a method for detecting a liquid level in a mold that is fast and does not cause a drift phenomenon.

[0009]

The present invention has been made for the purpose of solving the above problems, and the gist thereof is as follows.

First, in the method of detecting the liquid level in the mold in continuous casting, the liquid level value calculated by calculation based on the temperature detection value obtained from the temperature detecting element installed in the mold, and the mold level Using the liquid level value obtained by calculating based on the γ-ray intensity detection value obtained by detecting the γ-ray from the γ-ray generation source on one side with the γ-ray detector on the other side of the mold, The liquid level level value is characterized by adding a short cycle fluctuation part of the liquid level level value based on the γ-ray intensity detection value and a long cycle fluctuation part of the liquid level level value based on the temperature detection value. This is a method for detecting the liquid level in the mold.

As a result, the γ-ray method, in which the measured value drifts due to the foreign substances adhering to the inside of the mold but the response speed is fast, and the temperature detection method, in which the absolute value of the liquid level can be measured but the response speed is slow, are combined. As a result, it is possible to realize the liquid level detection in the mold with a fast response speed and no drift. That is, by removing only the short-cycle fluctuation part of the detected value by the γ-ray method, the drift is erased and only the liquid level level fluctuation information of the short cycle is taken out, and only the long-cycle fluctuation part of the detected value by the temperature detection method is extracted. By taking out only the liquid level level fluctuation information of a long period by taking it out, it is possible to obtain a liquid level value with a fast response speed and no drift by adding both.

Secondly, in the method of detecting the liquid level in the mold in continuous casting, the liquid level value obtained by calculation based on the temperature detection value obtained from the temperature detecting element installed in the mold, and the mold level Using the liquid level value obtained by calculating based on the γ-ray intensity detection value obtained by detecting the γ-ray from the γ-ray generation source on one side with the γ-ray detector on the other side of the mold, The difference value is obtained by subtracting the long-cycle fluctuation part of the liquid level level value based on the temperature detection value from the long-cycle fluctuation part of the liquid level level value based on the γ-ray intensity detection value, and abrupt time change of the difference value. The liquid level in the mold is characterized in that bump level control is performed to remove the minute portion, and a value obtained by subtracting the value after the bumpless control from the liquid level level based on the γ-ray intensity detection value is used as the liquid level value. This is a level detection method.

As a result, in addition to the effect of the first invention as it is, even when the detection value of the thermocouple system fluctuates abruptly due to the disconnection of the thermocouple or the like, the bumpless control causes abrupt fluctuation. By subtracting the value controlled for gentle fluctuation from the γ-ray detection value,
In the liquid surface level control using the liquid surface level detection value according to the present invention, it is possible to prevent a sudden control abnormality from occurring.

Thirdly, the absolute value of the difference obtained by subtracting the long-cycle fluctuation part of the liquid level level value based on the temperature detection value from the long-cycle fluctuation part of the liquid level level value based on the γ-ray intensity detection value. The method for detecting the liquid level in a mold according to the first or second invention is characterized in that an alarm is issued as an abnormality in the liquid level when the liquid level exceeds a reference value.

This makes it possible to detect that the drift in the γ-ray system has become excessive, detect the occurrence of molten metal splash in the mold, and abnormal adhesion of powder bears, and take an early action.

Fourthly, the presence or absence of disconnection of the temperature detecting element and the signal wiring installed in the mold is detected, and when the disconnection is detected, the liquid level value based on the γ ray intensity detection value is set as the liquid level value. The method for detecting a liquid level in a mold according to any one of the first to third inventions, characterized in that.

Thus, in addition to the first and second aspects of the invention, when the detection element of the temperature detection method is broken, the detection is automatically switched to the γ-ray method only, and the control continues normally without interruption. It becomes possible.

Fifth, in place of liquid level detection in which γ-rays from a γ-ray source on one side of the mold are detected by a γ-ray detector on the other side of the mold, a vortex sensor arranged above the mold is used. The mold according to any one of claims 1 to 4, wherein one of liquid level detection, liquid level detection based on an image of an industrial television camera, and liquid level detection based on a reflected signal of an emitted laser beam is used. This is a method of detecting the internal liquid level.

Sixth, in a device for detecting a liquid level in a mold in continuous casting, a liquid of a temperature detection method which is calculated by calculating a liquid level value based on a temperature detection value obtained from a temperature detecting element installed in the mold. The liquid level is calculated based on the γ-ray intensity detection value obtained by detecting the γ-ray from the γ-ray source on one side of the mold and the γ-ray detector on the other side of the mold. Γ-ray type liquid level detector, a high-pass filter for extracting a short cycle fluctuation part of the liquid level value by the γ-ray type liquid level detector, and the temperature detection type liquid level detector A low-pass filter (low-pass filter 1) for extracting a long-cycle fluctuation portion of the liquid level value according to the above, and an adder for adding the high-pass filter output and the low-pass filter output to obtain a liquid level value. A detection device in the mold fluid level characterized. It is an apparatus for carrying out the first invention.

Seventh, in a device for detecting the liquid surface level in a mold in continuous casting, a liquid of a temperature detection system which is calculated by calculating a liquid surface level value based on a temperature detection value obtained from a temperature detecting element installed in the mold. The liquid level is calculated based on the γ-ray intensity detection value obtained by detecting the γ-ray from the γ-ray source on one side of the mold and the γ-ray detector on the other side of the mold. And a low-pass filter (low-pass filter 2) for extracting a long-cycle fluctuation portion of the liquid level value based on the γ-ray liquid level detector, and the temperature detection Method Low-pass filter (low-pass filter 1) that extracts a long-cycle fluctuation portion of the liquid-level value by the liquid-level detector, and subtracts the output of the low-pass filter 1 from the output of the low-pass filter 2 to obtain the difference. A subtractor, a bumpless controller that performs bumpless control that removes a sudden time change of the difference value, and a bumpless controller output from the liquid level value by the γ-ray system liquid level detector. And a subtractor for subtracting the value to obtain a liquid level value. It is an apparatus for carrying out the second invention.

Eighth, a low-pass filter (low-pass filter 2) for extracting a long-cycle fluctuation portion of the liquid level value by the γ-ray type liquid level detector, and the low-pass filter 1 from the output of the low-pass filter 2 And a liquid level abnormality alarm generator for issuing an alarm as a liquid level abnormality when the difference value becomes larger than a reference value. Alternatively, it is a device for detecting a liquid level in a mold according to the invention of Item 7. It is an apparatus for carrying out the third invention.

Ninth, a temperature detecting element installed in the mold and a disconnection detector for detecting the presence or absence of disconnection of the signal wiring, and when the disconnection detector detects disconnection, a γ-ray type liquid level detector is used. The liquid level level detecting apparatus for a liquid level in a mold according to any one of the sixth through eighth aspects of the present invention, further comprising a switch for changing the liquid level level to the liquid level value. It is an apparatus for carrying out the fourth invention.

The tenth is a vortex type liquid level detector which detects the liquid level by a vortex sensor arranged above the mold instead of the γ-ray type liquid level detector, and the liquid level is detected by an image of an industrial television camera. Sixth to ninth features, which use one of an ITV type liquid level detector for detecting a liquid level and a laser type liquid level detector for detecting a liquid level based on a reflected signal of the emitted laser light. 1 is a device for detecting a liquid level in a mold of the invention.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A mold for continuous casting is usually made of copper having a water cooling mechanism inside, and a copper mold surrounds four spaces of a space into which molten metal is injected, and the molten metal injected from above is a mold. Solidification starts from the part in contact with and is drawn out below the mold.

In the γ-ray type liquid level detector, a γ-ray source 4 is arranged on one side of the mold 1 as shown in FIG. 1, and the intensity of γ-rays passing through the mold 1 is measured by the other side of the mold. It is detected by the γ-ray detector 6 arranged on the side. A region for detecting γ-rays in the γ-ray detector 6 has a width in the vertical direction of the mold, and the assumed liquid level 2 in the mold is near the center of the γ-ray detection region. Molten metal does not easily transmit γ rays, so if the liquid level 2 rises, γ
Since the line detection intensity becomes weak and the γ-ray detection intensity becomes strong as the liquid level 2 descends, the liquid level can be obtained from the detection intensity.

In the temperature detecting type liquid level detector, a temperature detecting element insertion hole is provided from the outside in a copper mold 1, and a temperature detecting element, specifically, a thermocouple 7 is inserted therein. The tip of the insertion hole is located as close as possible to the surface of the inner surface of the mold that contacts the molten metal. A plurality of temperature detecting elements are installed vertically in the mold. The temperature detecting element below the liquid surface 2 near the portion where the molten metal exists detects a high temperature,
Since the temperature detecting elements near the portion where the molten metal does not exist above detect a low temperature, the liquid level can be detected by comparing the detected temperatures of the temperature detecting elements arranged vertically. The calculating means for detecting the liquid surface level from the comparison result of the detected temperatures can be determined based on the liquid surface level detected by other means such as visual inspection and the actual detected temperature.

As means for extracting only the short-cycle fluctuation portion or the long-cycle fluctuation portion from the liquid surface level value detected by each liquid surface level detector, the signal can be obtained by passing the signal through a high-pass filter or a low-pass filter, respectively. As the high-pass filter and the low-pass filter, specifically, an analog filter using a condenser or a coil may be used, or a method of digitally processing a signal to extract only low frequency components and high frequency components may be adopted.

FIG. 1 shows the whole including the signal processing of the first and sixth inventions. By extracting only the short period fluctuation part from the liquid level value 10 by the γ-ray type liquid level detector, only the short-term and rapid fluctuation information of the liquid level is extracted, and the long-term and gentle fluctuation of the liquid level is obtained. Drift signals due to fluctuations and molten metal splashes or powder bear deposits on the mold are eliminated. Further, by extracting only the long cycle part from the liquid level value 11 by the temperature detection type liquid level detector, only the long-term and gentle fluctuation information of the liquid level is extracted, and the mold is oscillated vertically. The fluctuating signal caused by causing it to be deleted. Therefore, by adding the two extracted signals, the short-term and rapid fluctuation information of the liquid surface level and the long-term and gentle fluctuation information of the liquid level are added, and the actual liquid is accurately measured in the long-term and short-term. It is possible to obtain the liquid surface level value 12 that matches the surface level.

FIG. 2 shows the whole including the signal processing of the second and seventh inventions. The bumpless control according to the second aspect of the present invention is specifically a method of including a first-order lag element in the indicated value,
Alternatively, it is performed by a method of shaping so that the indicated value changes like a ramp.

FIG. 2 shows the third embodiment in addition to the second or seventh invention.
Alternatively, the liquid level abnormality detection of the eighth invention is included. Further, FIG. 3 shows an invention obtained by adding the third or eighth invention to the first or sixth invention. That is, the absolute value of the difference obtained by subtracting the long-cycle fluctuation part of the liquid surface level value 11 based on the temperature detection value from the long-cycle fluctuation part of the liquid surface level value 10 based on the γ-ray intensity detection value is exactly γ. The magnitude of the drift of the line method detection value is shown. The large drift indicates that the amount of molten metal splash and powder bear attached in the mold is increasing, and it is important to inform such information to the operator and control system as an alarm. . This object can be achieved by reading this difference value into a comparator and issuing an alarm when it becomes larger than a predetermined reference value.

Disconnection detection and third of the fourth or ninth invention
Alternatively, a second or seventh invention including the eighth invention is shown in FIG. The presence / absence of disconnection of the temperature detecting element and the wiring can be easily known by confirming the presence / absence of conduction of a signal from the temperature detecting element. When disconnection occurs, a thermocouple type liquid level detector generates a disconnection detection signal. If a disconnection is detected, the temperature detection type liquid level detector cannot be used.Therefore, both the short cycle and long cycle liquid level information can be detected as the detected value by the detection result of the γ ray type liquid level detector. To do. However, immediately before switching, the output of the γ-ray type liquid level detector is likely to include a drift part, so calculate the drift component value immediately before disconnection,
It is necessary to delete this value from the output of the γ-ray type liquid level detector as a constant value before switching. As the drift component value immediately before the disconnection, the long-term fluctuation portion of the liquid level level value based on the γ-ray intensity detection value of the third or eighth invention is changed to the long-term value of the liquid level level value based on the temperature detection value. Since the absolute value of the difference after subtracting the period variation part indicates exactly the magnitude of the drift of the γ-ray detection value, always store this difference value at the immediately preceding timing,
At the same time that a disconnection occurs, this difference value immediately before is read,
The drift component value can be used in the fourth invention.

According to the method shown in FIG. 4, even if the temperature detecting element is broken, the γ-ray system can be switched smoothly, so bumpless control is not always necessary. If bumpless control is excluded in the second invention, control equivalent to that in the first invention is performed. That is, in the control on the liquid level value of the γ-ray system, the first invention extracts the short period part and uses it for the control, but in the second invention, the long period part is extracted and finally This is because it is equivalent to using a value obtained by subtracting the long period portion from the γ-ray system liquid level level for control.

Instead of the γ-ray type liquid level detector, a vortex type, ITV type and laser type liquid level detector may be used. As described above, the liquid level detectors of these systems have a high response speed to a sudden change in the liquid level. On the other hand, especially in the ITV system and the laser system, the absolute value of the liquid surface level cannot be grasped in powder casting. Therefore, when combined with the thermocouple system in the present invention, abrupt liquid surface level change and liquid surface absolute value can be obtained. Therefore, the liquid level can be detected with high accuracy.

[0034]

[Example] Size of slab in mold 125 mm x 125 mm
The present invention was applied to the continuous billet casting of steels. γ
As a linear system liquid level detector, a ¹³⁷ Cs γ-ray source 4 is arranged on one side of the mold 1 and γ-ray source 4 on the other side of the mold 1.
The γ-ray detector 6 having the width of the line detection region of 100 mm in the mold height direction was arranged. As the temperature detection type liquid level detector, three thermocouple insertion holes are arranged side by side on the side surface of the copper mold 1 in the height direction of the mold, and the thermocouple 7 is inserted into the thermocouple insertion hole. The temperature detection end was used. The distance between the thermocouple insertion holes was fixed at 15 mm, and the distance from the surface of the inner surface of the mold to the temperature detection end was 4 mm. Regarding the relationship between the actual measured temperature of each thermocouple and the liquid level value, the calculation logic is determined based on the data of the measured temperature and the actual liquid level, and the liquid level value is calculated based on that calculation logic. We were able to.

Inventive Example No. No. 1 of the present invention is a combination of the first invention and the third invention as shown in FIG. 2 is a combination of the second invention, the third invention, and the fourth invention as shown in FIG. Comparative Example N
o. No. 1 is an example using only the γ-ray type liquid level detector. No. 2 is an example using only the temperature detection type liquid level detector. The details of the liquid level detector in both the inventive example and the comparative example are as described above.

The low-pass filter for the detection value of the temperature detection method, the low-pass filter for the detection value of the γ-ray method, and the high-pass filter for the detection value of the γ-ray method used in the examples of the present invention all have a cutoff frequency of 0.1 to 0.1. It was set within the range of 1 Hz. The low-pass filter, high-pass filter, addition, subtraction, comparison, and bumpless control in this embodiment were all carried out by program control for performing digital calculation in a digital sequencer.

In actual casting, the liquid level in the mold was detected by using the detection devices of the present invention example and the comparative example. FIG. 5 shows the liquid level detection result according to this embodiment.
The line graph shows the detection results of the detection devices of the present invention example and the comparative example, and the black circles in the figure are the actual liquid surface levels observed by observing the inside of the mold at regular intervals. Comparative Example No. Regarding No. 1, as the casting progressed, a drift dissociated from the actual liquid surface level occurred, and this Comparative Example No. It was difficult to perform the liquid level control based on the signal obtained by No. 1. In addition, Comparative Example No. For No. 2, no detection signal corresponding to a sudden change in the liquid surface level was obtained, and only a signal with noise of the same frequency as the mold vibration was added, but the drift differed from the actual liquid surface level. Was not observed. On the other hand, the present invention example No. 1, No. Two
In both cases, the occurrence of drift that deviated from the actual liquid level was not seen, and a signal corresponding to a sudden change in the liquid level was obtained, which was sufficient as the liquid level value for automatic control of the liquid level. I got a usable signal.

Inventive Example No. In 2, the absolute value of the difference obtained by subtracting the long-cycle fluctuation part of the liquid level level value based on the temperature detection value from the long-cycle fluctuation part of the liquid level level value based on the γ-ray intensity detection value, The difference value was compared with the actual adhesion state of the molten metal splash or powder bear in the mold. As a result, the correlation that the difference value increases as the adhesion inside the mold increases, and there is a possibility that normal casting cannot be performed. I was able to set it. As a result of issuing an alarm based on this reference value, it is no longer necessary to arrange an operator to monitor the situation in the mold, and it is possible to reduce the personnel required for the operation for continuous casting.

Inventive Example No. 1, No. In 2, the disconnection condition was created by artificially disconnecting the signal line of the temperature detection type detector, and the actual results of the liquid level value after that were confirmed. Inventive Example No. Regarding No. 2, as shown in FIG. 5, the detection could be smoothly continued without being affected by the drift accumulation of the γ-ray type detector immediately after the wire breakage. However, since the drift value changes with the passage of time, it goes without saying that it is necessary to repair the disconnection of the temperature detection type detector at the earliest possible timing and restore the original control.

[0040]

According to the present invention, by detecting the liquid level level detected by the γ-ray method and the liquid level level detected by the temperature detection method and then synthesizing the signals, the liquid level detection with high response speed and no drift can be performed. It is possible to get the value. As a result, the liquid level control with high accuracy can be performed in continuous casting, and the running cost can be reduced. In particular, when powder casting is performed in small-section billet continuous casting where it is difficult to use swirl type liquid level detection or ITV type liquid level detection, it is the first time to perform accurate liquid level detection at low running cost. It became possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing the first invention.

FIG. 2 is a block diagram showing the second and third inventions.

FIG. 3 is a block diagram showing the first and third inventions.

FIG. 4 is a block diagram showing the second, third and fourth inventions.

FIG. 5 is a diagram showing the liquid level detection results of the example of the present invention and the comparative example.

[Explanation of symbols]

1 mold 2 liquid level 3 slab 4 γ-ray source 5 Radiation γ-ray region 6 γ-ray detector 7 thermocouple 8 γ-ray intensity detection value 9 Temperature detection value 10, 11, 12 Liquid level value 13 adder 14 Subtractor 15 Changeover switch

Claims (10)

(57) [Claims] 1. In a method of detecting a liquid level in a mold in continuous casting, a liquid level value calculated by calculation based on a temperature detection value obtained from a temperature detection element installed in the mold and one of the molds. Using the liquid level value calculated by calculating the γ-ray from the γ-ray source on the side of the γ-ray intensity detection value obtained by detecting the γ-ray detector on the other side of the mold, the γ-ray A mold characterized by adding a short-cycle fluctuation part of the liquid level level value based on the strength detection value and a long-cycle fluctuation part of the liquid level level value based on the temperature detection value to obtain a liquid level value. How to detect the internal liquid level. 2. A method of detecting a liquid level in a mold in continuous casting, wherein the liquid level value calculated by calculation based on a temperature detection value obtained from a temperature detection element installed in the mold and one of the molds Using the liquid level value calculated by calculating the γ-ray from the γ-ray source on the side of the γ-ray intensity detection value obtained by detecting the γ-ray detector on the other side of the mold, the γ-ray The long-cycle fluctuation part of the liquid surface level value based on the temperature detection value is subtracted from the long-cycle fluctuation part of the liquid level level value based on the intensity detection value to obtain a difference value, and the abrupt time change of the difference value is calculated. Performing bumpless control to delete, the value obtained by subtracting the value after the bumpless control from the liquid level value based on the γ-ray intensity detection value is taken as the liquid level value of the mold level. Detection method. 3. The absolute value of the difference obtained by subtracting the long-cycle fluctuation part of the liquid level level value based on the temperature detection value from the long-cycle fluctuation part of the liquid level level value based on the γ-ray intensity detection value. The method for detecting the liquid level in the mold according to claim 1 or 2, wherein an alarm is issued as an abnormality in the liquid level when the liquid level becomes larger. 4. A liquid level level value based on the γ-ray intensity detection value is detected when the presence or absence of a break in the temperature detection element and signal wiring installed in the mold is detected. The method for detecting a liquid level in a mold according to any one of claims 1 to 3. 5. A liquid level by a vortex sensor arranged above the mold instead of liquid level detection in which γ-rays from a γ-ray source on one side of the mold are detected by a γ-ray detector on the other side of the mold. 2. One of level detection, liquid level detection based on an image of an industrial television camera, and liquid level detection based on a reflected signal of an emitted laser beam is used.
5. The method for detecting the liquid level in the mold according to any one of 4 to 4. 6. A temperature detecting method liquid level which is calculated by calculating a liquid level value based on a temperature detection value obtained from a temperature detecting element installed in a mold in a device for detecting a liquid level level in a mold in continuous casting. The detector and γ on one side of the mold
A γ-ray type liquid level detector for calculating the liquid level based on the γ-ray intensity detection value obtained by detecting the γ-ray from the radiation source with the γ-ray detector on the other side of the mold, A high-pass filter for extracting a short-cycle fluctuation part of the liquid level value by the γ-ray type liquid level detector, and a long-cycle fluctuation part of the liquid level value by the temperature detection type liquid level detector. An apparatus for detecting a liquid level in a mold, comprising: a low-pass filter (low-pass filter 1) for extraction; and an adder for adding the high-pass filter output and the low-pass filter output to obtain a liquid level value. 7. A liquid level level detecting method for a liquid level level in a mold in continuous casting, which is obtained by calculating a liquid level value based on a temperature detection value obtained from a temperature detecting element installed in the mold. The detector and γ on one side of the mold
A γ-ray type liquid level detector for calculating the liquid level based on the γ-ray intensity detection value obtained by detecting the γ-ray from the radiation source with the γ-ray detector on the other side of the mold, Of the liquid level values based on the γ-ray type liquid level detector, a low-pass filter (low-pass filter 2) for extracting a long-cycle fluctuation portion of the liquid level values, and the liquid level value by the temperature detection type liquid level detector. Of the low-pass filter (low-pass filter 1) for extracting the long-cycle fluctuation part of the low-pass filter, a subtractor for subtracting the output of the low-pass filter 1 from the output of the low-pass filter 2 to obtain a difference value, and a rapid time change amount of the difference value. A bumpless controller that performs bumpless control to be deleted and a subtraction that subtracts the output value of the bumpless controller from the liquid level value by the γ-ray type liquid level detector to obtain the liquid level value. DOO-mold liquid level of the detection device, characterized in that it comprises a. 8. A low-pass filter (low-pass filter 2) for extracting a long-cycle fluctuation portion of a liquid-level value detected by a γ-ray type liquid-level detector, and an output of the low-pass filter 2 to an output of the low-pass filter 1. And a liquid level abnormality alarm generator that issues an alarm as a liquid level abnormality when the difference value becomes larger than a reference value. 7. A device for detecting a liquid level in a mold according to 7. 9. A disconnection detector for detecting the presence or absence of disconnection of a temperature detection element and a signal wiring installed in a mold, and a liquid level by a γ-ray type liquid level detector when the disconnection detector detects the disconnection. 9. The apparatus for detecting the liquid level in the mold according to claim 6, further comprising a switching device for setting the level value to the liquid level value. 10. A vortex type liquid level detector for detecting the liquid level by a vortex sensor arranged above the mold instead of the γ-ray type liquid level detector, and the liquid level is detected by an image of an industrial television camera. One of the ITV type liquid level detector and the laser type liquid level detector which detects the liquid level by the reflected signal of the irradiated laser beam.
The liquid level detection device in a mold according to claim 6, wherein a seed is used.