JPH06277814A - Breakout detector for continuous caster - Google Patents

Abstract

PURPOSE:To execute the detection of breakout with an optical sensor having simple structure. CONSTITUTION:The temp. sensor 16 is constituted by winding an optical fiber in spiral form on the outer peripheral surface of a mold 15. A measuring instrument 18 executes the detection of the temp. by making incident pulse light from one end of the optical fiber constituting this temp. sensor 16 and taking out the scattered light generated in the inner part of the optical fiber in this method to measure the intensity of this scattered light. A controller 19 executes a prescribed calculation for the output from the measuring instrument 18 to decide presence/absence of the breakout.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breakout detecting device in a continuous casting machine.

[0002]

2. Description of the Related Art In continuous casting by a continuous casting machine,
The molten steel poured into the mold is cooled in the mold, but when the cast product is pulled out from the mold, the solidified shell may be broken and the internal molten steel may flow out, so-called breakout may occur. Therefore, for stable operation of the continuous casting machine, it is important to detect or predict and suppress breakout, and various methods have been tried in the past.

For example, a plurality of thermocouples are embedded in a mold plate forming a mold, the wall surface temperature of the mold plate is spot-measured, and information processing is performed by a dedicated arithmetic unit and a dedicated logic such as a neural network. There is a way. Further, a method of using an optical fiber instead of a thermocouple is disclosed in Japanese Patent Laid-Open No. 61-219456.

[0004]

Such a conventional breakout prediction method can measure a wide range of temperature because it can measure only a measuring point where a sensor such as a thermocouple or an optical fiber is installed. Therefore, it is necessary to install a large number of sensors, which complicates the device and increases the cost.

Accordingly, it is an object of the present invention to provide a breakout detecting device having a new sensor structure which eliminates the drawbacks of the breakout predicting method in the conventional continuous casting machine.

[0006]

According to the present invention, an optical fiber spirally wound around the outer peripheral surface of a mold plate in a mold, and pulsed light is made incident from one end of the optical fiber, and the optical fiber is provided. And a controller connected to the optical fiber so as to extract reflected and scattered light inside, and a controller connected to the measuring device and performing a predetermined calculation on the output of the measuring device to determine the presence or absence of a breakout. And a display terminal device connected to the controller, a breakout detection device is provided.

Further, in the breakout detecting device of the present invention, the measuring instrument is configured to detect the Raman scattered light reflected from the optical fiber and measure its intensity.

Further, in the breakout detecting device according to the present invention, the measuring device detects the Raman scattered light reflected from the optical fiber, and measures the time from the incidence of the optical pulse to the reception of the reflected scattered light. It is configured to measure.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the breakout detection device of the present invention, and FIG. 2 is an enlarged perspective view showing the essential parts of the sensor section thereof.

In FIG. 1, the molten steel 12 in the ladle 11
Is supplied into the mold 15 through the sliding nozzle 13 and the dipping nozzle 14. The slab 21 supplied into the mold 15 and cooled and solidified is pulled out from the lower part of the mold 15. A temperature sensor 16 made of an optical fiber is installed in the mold 15, and an input end of the temperature sensor 16 is connected to a measuring instrument 18 via an optical fiber line 17. The measuring instrument 18 generates an optical pulse and transmits it to the optical fiber line 1
The temperature sensor 16 is supplied to the input end of the temperature sensor 16 via the light sensor 7, and as described later, the temperature sensor 1
The scattered light generated in 6 is received via the optical fiber line 17.

The measuring instrument 18 detects the temperature from the received scattered light and supplies it to the controller 19. The controller 19 performs a predetermined calculation on the output of the measuring instrument 18 to determine the presence or absence of breakout. A display terminal device 20 for a man-machine interface is connected to the controller 19.

FIG. 2 shows the structure of the temperature sensor 16 installed in the mold 15 shown in FIG. 1. An optical fiber 23 is spirally wound around the outer peripheral surface or inside of a cylindrical mold plate 22 having a rectangular cross section. It has been turned. The larger the number of turns of the optical fiber 23, the better. The input end 24 of this optical fiber 23
Is connected to the measuring instrument 18 via the optical fiber line 17 of FIG. 1, and the other end is open.

The operation of the breakout detecting device of the present invention thus constructed will be described. The measuring instrument 18 generates an optical pulse and supplies it to the input end 24 of the optical fiber 23 constituting the temperature sensor 16. The optical pulse supplied to the optical fiber 23 passes through the spiral optical fiber 23 at the other end 2
It progresses toward 5, and in each part in the process of progressing, it slightly propagates and progresses while being attenuated.

In some of the scattered light, the wavelength of the incident light is slightly shifted as a result of the transfer of energy with the lattice vibration of the quartz molecule of the optical fiber. That is, when energy is applied to the lattice motion, the wavelength of light shifts to the long wavelength side, which is called Stokes light. On the contrary, the wavelength of light given energy from the lattice motion shifts to the short wavelength side, which is called anti-Stokes light. The scattered light whose wavelength is shifted in this way is called Raman scattered light, but this Raman scattered light has temperature dependence, and in particular, the intensity of anti-Stokes light changes greatly with temperature, so scattered light is It is possible to measure the temperature by utilizing it.

That is, the optical pulse supplied to the input end 24 of the optical fiber 23 travels in the spiral optical fiber 23 toward the other end 25, and is scattered at each part in progress as described above. And a part thereof travels backward in the optical fiber 23 toward the input end 24 side. And the input end 2
Returning from 4 to the measuring instrument 18 via the optical fiber line 17,
Here, the intensity of anti-Stokes light is measured. Temperature data can be obtained from this intensity measurement. At this time, the measuring instrument 18 can obtain the position information of the scattered portion by measuring the time from the emission of the light pulse to the return of the scattered light.

As shown in FIG. 4, the temperature data based on the anti-Stokes light obtained by the temperature sensor 16 gradually decreases from the upper side to the lower side of the mold plate 22 as shown in FIG. In FIG. 4, the horizontal axis represents the distance from the upper side to the lower side of the mold plate 22, and the vertical axis represents the temperature. On the other hand, as shown in FIG. 3, when a breakout 32 occurs in a part of the shell 31 formed by solidifying the molten steel 12 that contacts the inner wall of the mold plate 22, the temperature data is
As shown in FIG. 5, peaks (typically 51 and 52 are shown) occur for each pitch of the spiral optical fiber 23 in the mold outer peripheral direction.

The controller 19 is supplied with these temperature data from the measuring instrument 18, and in order to know the temperature distribution from the upper side to the lower side of the mold plate 22, the mold plate 22 is subjected to a flattening process to develop an isothermal line. The processing produces a temperature distribution chart as shown in FIG. That is, FIG. 6 shows the mold plate 22 having the side surfaces A, B, C, and D of FIG. The controller 19 further includes a slab 21
The residence time in the mold plate 22 and the assumed steady temperature obtained by the molten steel solidification coefficient are compared. At the same time, the temperature distribution change, that is, the size of the high temperature portion, the temperature change per unit time, and the like are monitored in time series, and the presence or absence of breakout and the lower end of the mold plate 22 are reached by using, for example, a neural net method. The possibility of convergence of breakout during the period is determined, and the result is displayed on the display terminal device 20. The operator performs necessary operations on the continuous casting machine based on the displayed contents.

[0018]

As described above, according to the present invention, an optical sensor having a simple structure in which an optical fiber is spirally wound around an outer peripheral surface of a mold plate is used, so that the entire temperature from the upper side to the lower side of the mold plate is lowered. Since the distribution can be measured, the position of the breakout that has occurred in the mold plate and the state of its size, shape, etc. can be accurately known, which is extremely effective in predicting and suppressing the breakout.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a breakout detection device that is an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a main part of the sensor unit of the present invention shown in FIG.

FIG. 3 is a partially cutaway sectional view of a mold plate for explaining a breakout detection operation according to the present invention.

FIG. 4 is a graph showing the temperature distribution of the mold plate during normal operation of continuous casting, which is detected by the measuring instrument of the present invention.

FIG. 5 is a graph showing the temperature distribution of the mold plate when a breakout occurs, which is detected by the measuring instrument of the present invention.

FIG. 6 is a graph showing a temperature distribution subjected to a flattening process by the controller of the present invention, (A) showing a normal temperature distribution, and (B) showing a temperature distribution when a breakout occurs.

[Explanation of symbols]

 11 Ladle 12 Molten Steel 13 Sliding Nozzle 14 Immersion Nozzle 15 Mold 16 Temperature Sensor 17 Optical Fiber Line 18 Measuring Instrument 19 Controller 20 Display Terminal Device 21 Cast Piece 22 Mold Plate 23 Optical Fiber

Claims (3)

[Claims] 1. An optical fiber spirally wound around an outer peripheral surface of a mold plate in a mold, and pulsed light is made incident from one end of the optical fiber, and reflected and scattered light inside the optical fiber is taken out. A measuring instrument connected to the optical fiber, a controller connected to the measuring instrument, for performing a predetermined operation on the output of the measuring instrument to determine the presence or absence of breakout, and a display terminal connected to the controller. A breakout detection device in a continuous casting machine, comprising: 2. The breakout detection device according to claim 1, wherein the measuring device is configured to detect the Raman scattered light reflected from the optical fiber and measure the intensity thereof. . 3. The measuring device is configured to detect the Raman scattered light reflected from the optical fiber and measure the time from the incidence of the optical pulse to the reception of the reflected scattered light. The breakout detection device according to claim 2, wherein