JPH0543974Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an abnormality monitoring device installed in a molten metal injection device, such as a device for injecting molten steel in a tundish into a mold in continuous casting equipment.

[Conventional technology]

In continuous casting equipment, in order to prevent molten steel from overflowing from the mold and breakout, when pouring the molten steel in the tundish into the mold, the molten steel is injected to maintain the molten metal level in the mold at an appropriate level. It is necessary to control the level of the molten metal to adjust the amount of molten metal. For example, a slider that moves horizontally in accordance with the forward and backward movement of the drive cylinder is installed in the middle of the pouring nozzle that extends from the bottom of the tundish to the casting. A sliding gate is provided to change the opening of the nozzle, and a level detector for detecting the level of the molten metal inside the mold and a nozzle opening detector for detecting the opening of the pouring nozzle are installed. The injection device is configured to perform the control by moving the driving cylinder forward and backward based on the deviation between the former detection signal and a preset value of the hot water level, using the latter detection signal as a feedback signal. is used.

In a pouring device with such a configuration, the molten steel at the bottom of the tundish may be cooled and solidified by contact with the slider, and may adhere and grow near the sliding gate. There is a problem in that the above-mentioned hot water level control is hindered. Therefore, the applicant has proposed that a periodic signal (specifically, a sine wave signal) with a predetermined amplitude be used as the signal corresponding to the deviation.
The driving cylinder is moved forward and backward by a superimposed signal, and the slider is constantly moved in the opening and closing direction, thereby suppressing the adhesion and growth of solidified metal and promoting the falling off of the adhering metal, thereby controlling the hot water level. proposed an injection device with improved accuracy (Japanese Patent Application Laid-open No. 60-3952).

[The problem that the idea attempts to solve]

However, the accuracy of hot water level control decreased,
Factors that cause abnormalities in the state of molten steel injection are not limited to the adhesion of solidified metal near the sliding gate described above, but include, for example: (1) failure or deterioration of the molten metal level detector or nozzle opening degree detector; (2) Misadjustment or malfunction of the proportional device, integrator, or differentiator that processes the detection signals of both detectors. (3) Deterioration of the servo valve that switches the direction of supply of pressure oil to the drive cylinder or the drive cylinder. Deterioration of the hydraulic drive system, such as deterioration of the hydraulic oil (4) Incorporation of air into the hydraulic oil (5) Heat deformation of the slider of the sliding gate, etc. Even in injection equipment, the accuracy of the level control of the molten metal may decrease during operation, and abnormalities may occur in the molten steel injection state.If an abnormality occurs, it is necessary to determine which of the above factors is the cause of the abnormality. In addition to the drawback that it takes a lot of time to make a determination, if the abnormality is serious and directly linked to the overflow of molten steel from the mold or the occurrence of a breakout, the operation of the continuous casting equipment is stopped and the determination is made. I have no choice but to do
The problem was that it led to a decrease in operational efficiency.

The present invention has been developed in view of the above circumstances, and provides an abnormality monitoring device for a molten metal injection device that can quickly determine the occurrence of an abnormality and its cause when an abnormality occurs in the injection state of molten metal. The purpose is to

[Means to solve the problem]

The abnormality monitoring device for a molten metal injection device according to the present invention is equipped with a sliding gate that opens and closes an injection port from a molten metal container, and the device is equipped with a sliding gate that opens and closes an injection port from a molten metal container, and the device has a sliding gate that opens and closes an injection port from a molten metal container. To the deviation signal,
In an abnormality monitoring device for a molten metal injection device, the sliding gate is driven by a hydraulic device to maintain a melt level at a predetermined level according to a signal superimposed with a predetermined periodic signal, the periodic signal; means for detecting a phase difference between the periodic component and the periodic component appearing in the opening degree detection signal as the periodic signal is superimposed; and information regarding the time point at which the molten metal container is replaced; The detected phase difference of the means is compared with a predetermined value, and if the detected phase difference exceeds the predetermined value, it is determined that the sliding gate is abnormal. The present invention is characterized by comprising means for determining that there is an abnormality in the hydraulic system.

[Effect]

In this invention, if the phase difference is larger than a predetermined value, it is determined that there is an abnormality in the sliding gate or the hydraulic system for driving it, but if the phase difference is less than the predetermined value, it is determined that the problem is caused by other factors. judge.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof. FIG. 1 is a schematic block diagram of continuous casting equipment equipped with an abnormality monitoring device for a molten metal injection device according to the present invention (hereinafter referred to as the device of the present invention).

In the figure, 1 is the tandate, and 2
is a cylindrical mold with an open top and bottom and is placed below the tundish 1 at an appropriate distance apart. At the bottom of the tundish 1, a cylindrical pouring nozzle 3 that opens at the bottom of the tundish 1 extends downward, and its lower end penetrates into the mold 2 for an appropriate length. The molten steel 4 passes through the pouring nozzle 3 and is injected into the mold 2, absorbs heat through contact with the water-cooled inner wall surface of the mold 2, solidifies, and is covered with a solidified shell 4a on the outside. At this point, it is pulled out from the bottom of the mold 2 by the rotation of pinch rolls (not shown).

A sliding gate 5 for opening and closing the pouring nozzle 3 is installed in the middle of the pouring nozzle 3. The sliding gate 5 includes a flat slider 50 formed by penetrating in the thickness direction a circular hole having a diameter approximately equal to the inner diameter of the pouring nozzle 3, and The slider 50, which is substantially orthogonal to each other,
The pouring nozzle 3 is made up of a driving cylinder 51 that is horizontally moved according to the forward and backward movement of the driving cylinder 51, and the pouring nozzle 3 is opened according to the advancing movement of the driving cylinder 51 and closed according to the retracting movement of the driving cylinder 51. The opening degree of the pouring nozzle 3 that is opened and closed in this way is determined by using, for example, a digital scale as the forward and backward position of the drive cylinder 51, and is detected by a nozzle opening degree detector 52 attached to the drive cylinder 51. It's getting old. The double-pressure oil chambers of the drive cylinder 51 are communicated with the double-pressure oil chambers of the servo cylinder 53, and the servo cylinder 53 is connected to the pilot cylinder 54 through a common rod. The oil chambers are each connected to a hydraulic pump P via a servo valve 55. Then,
When the pressure oil generated by the hydraulic pump P is supplied to the pressure oil chamber on the advancing side or the retreating side of the pilot cylinder 54 according to the operation of the servo valve 55, the pressure generated between the pilot cylinder 54 and the pressure oil chambers is The drive cylinder 5 moves forward or backward depending on the difference, and the accompanying movement of the servo cylinder 53 moves in or out.
A pressure difference is generated between the two pressure oil chambers, and the driving cylinder 52 moves forward or backward, and the pouring nozzle 3 is opened or closed.

Note that the drive cylinder 51 is driven via a pilot cylinder 54 and a servo cylinder 53.
In addition to the so-called indirect control method, as shown by the broken line in FIG. A so-called direct control method may be used in which the cylinder 51 is directly moved forward and backward.

In order to detect the level of the molten steel 4 injected in this way in the mold 2, a molten metal level meter 6 is disposed opposite the surface of the molten steel in the mold 2. This hot water level meter 6 outputs a voltage corresponding to the current hot water level in the mold 2, using, for example, eddy current, thermocouple, or radiation.
The output signal is given to the comparator 7. Further, the comparator 7 is supplied with a set voltage corresponding to an appropriate hot water level from a level setter 8. The comparator 7 compares the signal input thereto from the hot water level meter 6 and the input signal from the level setter 8, and determines whether the output signal of the hot water level meter 6 corresponds to the set voltage at the level setter 8. If it exceeds, that is, mold 2
If the hot water level inside exceeds the set level,
In order to reduce the amount of molten steel injected and lower the level of the molten metal, a signal instructing the closure of the pouring nozzle 3 is sent, conversely, when the output signal of the molten metal level meter 6 falls below the set voltage, i.e. When the level of the molten metal in the mold 2 falls below a set level, the amount of molten steel injected is increased and a signal instructing the opening of the pouring nozzle 3 is outputted in order to raise the level of the molten steel.

The output signal of the comparator 7 is given to the servo amplifier 10, which controls the switching operation of the servo valve 55, together with the output signal of the nozzle opening degree detector 52. Further, an oscillator 11 is connected to the input side of the servo amplifier 10, and a sine wave signal generated by the oscillator 11 is given. They are starting to overlap. Servo amplifier 10
uses the signal input from the nozzle opening degree detector 52 as a feedback signal to give the current opening degree of the pouring nozzle 3, and controls the servo according to the opening/closing command signal inputted thereto from the comparator 7. Valve 5
5, the driving cylinder 51 is moved forward and backward as described above, and the pouring nozzle 3 is opened and closed.
The sine wave signal generated by the comparator 7 causes the servo valve 55 to constantly perform a switching operation at a predetermined period, regardless of whether the opening/closing command signal is generated from the comparator 7. The slider 50 of the sliding gate 5 is moved in the opening/closing direction with a period corresponding to the period of the sine wave signal and a stroke corresponding to the amplitude of the sine wave signal, and the solidified metal near the sliding gate 5 is moved. It works to suppress adhesion and growth, and to promote shedding of molten steel from solidified metal.

Reference numeral 12 in the figure denotes an abnormality determination unit using a microcomputer, and the output signal of the nozzle opening degree detector 52 and the sine wave signal output from the oscillator 10 are respectively input to the abnormality determination unit 12. The output signal of the phase difference detection section 13 is given. Further, when the tundish 1 is replaced, a tundish replacement signal generated by a process computer (not shown) or manually input by an operator is also input to the abnormality determination section 12. As mentioned above, the drive cylinder 51 that opens and closes the pouring nozzle 3 is driven by the output signal of the servo amplifier 11 on which the sine wave signal is superimposed, and is constantly moved in accordance with the sine wave signal. Therefore, the drive cylinder 5
The output signal of the nozzle opening detector 52, which detects the opening of the pouring nozzle 3 as one forward/backward position, includes a sine wave component corresponding to the sine wave signal.
The phase difference detection unit 13 compares this sine wave component with the sine wave signal that is the cause of the appearance of the component,
A phase difference occurring between the two is detected, and a signal corresponding to the detected phase difference is output to the abnormality determination section 12. The abnormality determination unit 12 monitors the signal input from the phase difference detection unit 13 while the continuous casting equipment is in operation, and sequentially stores changes in the signal, and monitors the melt level as described above. It is detected whether or not an abnormality has occurred in the level control, the cause of the abnormality is determined, and the occurrence of the abnormality and the determined cause are displayed on the display section 14 to notify the operator.

The abnormality determination unit 12 determines whether the phase difference signal input from the phase difference detection unit 13 exceeds a predetermined value, for example, if the phase difference exceeds 90 degrees.
Detect when an abnormality occurs. The predetermined value is determined depending on the frequency of the sine wave signal generated by the oscillator 11. Further, the abnormality determination unit 12 determines that when the phase difference changes during pouring of molten steel in one tundish 1, the cause of the abnormality is adhesion of solidified metal in the vicinity of the sliding gate 5 or thermal deformation of the slider 50. The content of the determination is displayed on the display unit 14. When this indication is made, the oscillator 11 is adjusted, for example, to change the amplitude of the sinusoidal signal, thereby further promoting the falling off of the solidified metal. If the abnormality is no longer determined as a result of this, it is sufficient to conclude that the abnormality is due to the adhesion of solidified metal and continue the operation.
If the determination of abnormality is continued, slider 50
If it is determined that this is due to thermal deformation, the operation may be temporarily suspended and the sliding gate 5 replaced.

In addition, by replacing the tundish 1, a tundish replacement signal is input to the abnormality determination section 12.
If the phase difference before and after this point changes significantly, the abnormality determining unit 12 determines that the cause of the abnormality is a defective mounting state of the sliding gate 5, and displays the content of the determination on the display unit 14. When this display is displayed, the abnormality can be avoided, for example, by temporarily suspending operation and properly installing the sliding gate 5.

In addition, regardless of whether or not the tundish 1 is replaced, if a state with a large phase difference continues to occur, the abnormality determination unit 12 determines that the cause of the abnormality is air mixed into the differential oil in the hydraulic drive system or the servo Valve 5
5 is determined to be malfunctioning, and the content of the determination is displayed on the display unit 14. If this display is made,
The operator adjusts the oscillator 11 to change the amplitude and frequency of the sinusoidal signal, and checks whether this changes the phase difference in a decreasing direction. As a result, if a change occurs, it can be determined that the cause of the abnormality is the former, so by venting the air from the hydraulic piping without stopping the operation, it is possible to restore the normal state and further prevent the change. If it does not occur, it is determined that the abnormality is due to the latter cause,
The operation may be temporarily interrupted and the servo valve 55 may be replaced.

Further, if the phase difference itself is not detected, the abnormality detection section 12 determines that the nozzle opening degree detector 52 is malfunctioning, and displays the determination content on the display section 14.
to be displayed. It goes without saying that when this display is displayed, the nozzle opening degree director 52 should be replaced immediately.

There is a known method for determining abnormalities in a control system based on the phase difference between a sinusoidal signal given as an input and the response of the control system to the signal. Sometimes, a sine wave signal is input to the servo valve 55 and the final output, which is the operation of the drive cylinder 51, is extracted as an output, and an abnormality in the control system is detected based on the phase difference between the two. There are many causes of abnormalities in the level control of continuous casting equipment, and most of them occur during operation, so the above-mentioned abnormality detection when the operation is stopped is meaningless. In order to suppress the adhesion and growth of solidified metal on the sliding gate 5, this device uses a sine wave signal superimposed on the input signal to the servo valve 55 to detect abnormalities in the control system during operation. In addition, the cause of the detected abnormality can also be determined.

Next, we will explain the results of actual operations in which the proposed device was applied to continuous casting equipment that produces round bars with diameters of 187 mm to 312 mm.

The casting speed is 2.0m/min to 3.0m/min,
The oscillator 11 generates a sine wave signal having a frequency of 0.8 to 1.2 Hz and an amplitude that allows the slider 50 to obtain an inching stroke of 5 mm to 10 mm, and the phase difference detection unit 13 detects a phase difference of 90 degrees or more. If detected, it is determined that an abnormality has occurred in the injection state.

As a result of one month of operation as described above, the following abnormalities were detected 12 times.

Abnormality of the sliding gate 5 7 times Air mixed into the hydraulic piping 4 times Malfunction of the servo valve 55 1 time In each of these abnormalities, the cause is correctly determined, and the prescribed measures are promptly taken accordingly. As a result, we were able to significantly improve operational efficiency.

Note that the signal superimposed on the opening/closing command signal to the opening adjustment section is not limited to the sine wave signal shown in this embodiment, but may be a rectangular wave signal, a triangular wave signal, etc. as long as it is a periodic signal. .

Further, in this embodiment, a case has been described in which the present apparatus is applied to continuous casting equipment, but it goes without saying that the application of the present apparatus is not limited to this.

〔effect〕

As detailed above, according to the device of the present invention, if an abnormality occurs during injection of molten metal, the occurrence of this abnormality can be quickly detected, and the factors that led to this abnormality can be determined, so that this abnormality can be detected. If the abnormality is mild, the cause can be eliminated without interrupting the infusion, and even if the abnormality is severe, the infusion can be interrupted and the cause of the abnormality can be eliminated according to the judgment result. , it is possible to quickly restart injection, and it has excellent effects such as greatly improving operational efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of continuous casting equipment equipped with the device of the present invention. 1... Tanditetsu, 2... Mold, 3... Pouring nozzle, 5... Sliding gate, 6...
Hot water level meter, 11... oscillator, 12... abnormality determination section, 13... phase difference detection section, 51... drive cylinder, 52... nozzle opening degree detector, 55... servo valve.

Claims (1)

[Claims for Utility Model Registration] Equipped with a sliding gate that opens and closes the injection port from the molten metal container, the deviation signal between the set value of the molten metal level at the injection destination and the detected value of the molten metal level is determined by a predetermined value. In an abnormality monitoring device for a molten metal injection device, the sliding gate is driven by a hydraulic device in order to maintain a melt level at a predetermined level according to a signal on which a periodic signal is superimposed, the periodic signal and the period. means for detecting a phase difference between the periodic component appearing in the opening degree detection signal as a result of superimposition of the target signal; and information regarding the time point at which the molten metal container is replaced; The detected phase difference is compared with a predetermined value, and if the detected phase difference exceeds the predetermined value, it is determined that the sliding gate is abnormal, and if the detected phase difference exceeds the predetermined value both before and after the replacement time, the hydraulic system An abnormality monitoring device for a molten metal injection device, comprising means for determining an abnormality in a molten metal injection device.