JPH07166229A - Instrument for measuring developing quantity of splash in vacuum refining vessel - Google Patents

Abstract

PURPOSE:To prevent spitting caused in a vacuum refining furnace. CONSTITUTION:A CCD camera 1 is arranged so as to be possible to pick up the vacuum-atmosphere on molten steel surface in the vacuum refining vessel for molten steel at the angle in the range of no vision of the molten steel surface. Picture signal from the CCD camera 1 is inputted to a computer 3 through a filter 2. The computer 3 inputs the picture signal at each fixed time and stores it in a frame 4, and difference figure between data inputted at the previous time and data inputted at this time, is obtd. and further, this difference figure is binarized by arranging a threshold value to the brightness level. Then the developing quantity of splash is calculated based on this binarized data. The binarized figure data is displayed on a CRT 6 for displaying a figure processing result. By this method, the developing quantity of splash can surely be grasped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to prevent spitting during vacuum refining of molten steel.
The present invention relates to a device for measuring the amount of splash generated in a vacuum refining tank.

[0002]

2. Description of the Related Art In refining molten steel in a vacuum atmosphere, air is evacuated from the vacuum tank to gradually reduce the pressure in the tank to a vacuum atmosphere, thereby facilitating bonding of oxygen and carbon in the molten steel to CO. It is designed to generate gas for decarburization.

During the decarburizing and refining process, when the degree of vacuum sharply decreases, the decarburizing reaction in the molten steel rapidly occurs, and a large amount of CO gas, which is a decarburizing reaction product, is generated at one time.
The generated CO gas rises in the molten steel and is discharged into the vacuum atmosphere. At this time, the molten steel particles (splash) are also discharged into the vacuum atmosphere along with the CO gas. This phenomenon is called spitting, but when spitting occurs, the following problems occur. That is, when the splash occurs, the splash adheres to the ferro-alloy input port of the vacuum chamber, the ferro-alloy input port is clogged, and the operation cannot be continued. And not only the operation will stop, but also heavy labor will force you to remove dangerous metal.

In order to prevent the generation of splash due to such spitting, if the evacuation speed is reduced to suppress the generation of spitting, the refining time is extended, the life of the refractory is shortened, and the production capacity is increased. There is a problem that Therefore, in order to accurately suppress the occurrence of spitting, it is necessary to understand the state of splash generation in the vacuum chamber and the status of the metal in the vicinity of the ferroalloy input port. Had to monitor the inside of the chamber from the skylight provided on the ceiling of the vacuum chamber.

[0005]

However, in the conventional method for monitoring the inside of the vacuum chamber, since the splash is seen against the background of the molten steel with high brightness, it is determined that the splash has occurred unless it is a very intense splash. There is a problem that you cannot do it. Further, even if the splash is visible, there is a problem that it cannot be determined how high the splash is scattered.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and provides a splash generation amount measuring device in a vacuum refining tank which can accurately grasp the generation state of splash. It is an object.

[0007]

A device for measuring the amount of splash in a vacuum refining tank according to the present invention can photograph a vacuum atmosphere on the surface of a molten steel in a vacuum refining tank at an angle at which the surface of the molten metal does not enter the field of view. The image pickup means installed in this way, a means for fetching and storing the image signal from the image pickup means at regular time intervals, and a means for obtaining a difference image for each pixel of the image data fetched last time and the image data fetched this time And means for binarizing this difference image with respect to the brightness level to obtain a binarized image,
It is provided with a means for calculating the splash generation amount based on the binarized image.

[0008]

Since the image pickup device according to the present invention is installed so that the vacuum atmosphere on the molten metal surface can be photographed at an angle such that the molten metal surface does not enter the field of view, it is not affected by the radiated light from the molten metal surface.
You can shoot a splash splashing in a vacuum atmosphere. In addition, since the difference image of the image data taken by each other after a certain period of time is obtained and the difference image is binarized with respect to the brightness level, only the image of the part that changes in this time interval is detected. Therefore, only a thing that momentarily occurs and disappears, such as a splash, is detected, and a change in the background brightness or the like is gentler than the splash, and therefore is not detected. Therefore, by processing the binarized image, the amount of splash generated can be accurately grasped.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A splash generation amount measuring apparatus in a vacuum refining tank according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the device configuration of this splash generation amount measuring device, and FIG. 2 is an explanatory diagram for explaining the splash detection logic.

[0010] The molten steel 22 is sucked from the molten steel ladle 21 to decarburize and refine, and on the side wall opposite to the ferroalloy input port 24 of the vacuum refining tank 23, at an angle where the molten metal surface 22a of the molten steel 22 does not enter the field of view, A CCD camera 1 is attached. The video signal from the CCD camera 1 passes through the filter 2 and is input to the computer 3. A frame memory 4 for storing image data is connected to the computer 3. The image processing result display CRT 6 is used to display an image of the splash obtained as a result of the implementation of the present invention. In this example, the CCD camera 1 is attached so that the ferroalloy input port 24 is in the field of view, and the signal from the CCD camera is
It is used to directly enter the CRT 5 for monitoring the ferroalloy input port 24 and monitor the ferroalloy input port 24.

As its internal processing, the computer 3 fetches an image signal from the image pickup means at a fixed time interval and stores it in the frame memory 4, and the image data previously fetched and stored in the frame memory 4 and this time. A difference image for each pixel of the captured image data is obtained, and the difference image is binarized with respect to the brightness level to obtain a binarized image. Then, the splash generation amount is calculated based on the binarized image. The binarized image is displayed on the CRT 6 for displaying the image processing result.

The CCD camera 1 is housed in a cooling box 7 and is always cooled. Also, C
The eaves 8 is provided on the CD camera 1 mounting hole,
By arranging the CCD camera 1 for monitoring the vacuum refining tank 23 at a deep position, the CCD camera 1 is burned out by molten steel scattered to the upper part inside the vacuum refining tank 23 and dripping along the inner wall of the vacuum vacuum refining tank 23. I try to prevent it.

Reference numeral 26 in FIG. 1 is a vacuum exhaust port, 27.
Is an evacuation device. Next, with reference to FIG. 2, a method of grasping the generation of the splash 25 by this device will be described. When the spitting does not occur, the image 11 in the vacuum refining tank 23 and the image 12 of the same image after a predetermined time.
Since only the image 13 of the ferroalloy input port 24 is shown, even if there is a change in the brightness of the visual field of the CCD camera 1 due to a change in the molten metal condition, the difference image 14 resulting from the difference between the two is obtained.
, Only a thin image 15 of the ferroalloy input port 24 is captured, and nothing is captured in the image 16 in which only a high brightness portion is left by binarizing the brightness by setting a threshold value.

On the contrary, in the image 17 when spitting occurs, the image 13 of the ferroalloy input port 24 and the image 18 of the splash 25 are shown. Therefore, the difference image 19 between the image 12 before spitting and the image 17 when spitting occurs
In addition to the thin image 15 of the ferroalloy input port 24, the image 18 of the splash 25 is shown. Then, as described above, in the image 20 in which only the high-luminance part is binarized and left,
Only the image 18 of the splash 25 is shown. Therefore, by adding up the area of the image 18 of the splash 25 of the image 20, it is possible to accurately grasp the generation amount of splash. As a result, the vacuum evacuation speed is accelerated or decelerated based on the generation amount of the splash 25 to suppress the reaction and prevent the occurrence of spitting, and the splash 25 prevents the ingot from adhering to the ferroalloy input port 24. Can be prevented.

[0015]

Since the present invention is configured as described above, the amount of splash generated can be accurately grasped.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a device configuration of a splash generation amount measuring device.

FIG. 2 is an explanatory diagram illustrating a splash detection logic.

[Explanation of symbols]

 1 CCD camera 3 Computer 4 Frame memory 6 CRT screen for displaying image processing results

Claims (1)

[Claims] 1. An image pickup means installed so that a vacuum atmosphere on a molten metal surface in a molten steel vacuum refining tank can be photographed at an angle such that the molten metal surface does not enter the field of view, and an image signal from the image pickup means at regular time intervals. A means for capturing and storing, a means for obtaining a difference image for each pixel of the image data captured last time and the image data captured this time, and means for binarizing the difference image with respect to the brightness level to obtain a binarized image. And a splash generation amount measuring device in the vacuum refining tank, which has a means for calculating the splash generation amount based on the binarized image.