Molten metal temperature measuring and monitoring device, molten metal temperature measuring and monitoring method, and program

Abstract

To provide a continuous temperature measurement monitoring technique of installing an imaging unit such as a camera at a position where a molten metal surface in a facility can be imaged in a molten metal holding facility and continuously measuring the temperature of a molten metal from luminance information of an image obtained by imaging the molten metal surface.SOLUTION: A temperature measurement monitoring device of a molten metal which is installed in a facility that holds the molten metal and can measure the temperature of the molten metal and monitor the state in the facility, comprises: an imaging unit which is positioned on the upper side of the monitoring imaging hole of the facility and captures an image of a molten metal surface in the facility through a monitoring imaging hole; a rotary disk which is positioned on the lower side of the monitoring imaging hole and has a slit that rotates at a fixed rotational speed; a control unit which controls timing at which the imaging unit captures an image of the molten metal surface and the rotational speed of the rotary disk; and a calculation unit which calculates the temperature of the molten metal surface on the basis of the image of the molten metal surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for measuring detailed information on the surface of a molten metal in a facility that holds the molten metal. In particular, the present invention relates to a molten metal temperature measuring and monitoring device that can continuously measure the temperature of the molten metal and monitor the condition inside the facility, and a molten metal temperature measuring and monitoring method and program using the molten metal temperature measuring and monitoring device. [Background technology]

[0002] Examples of conventional equipment for holding molten metal include converters, electric furnaces, RH vacuum degassing tanks, KR desulfurization equipment, hot metal ladles, molten metal ladles, molten steel ladles, tundishes, etc. As a method for measuring the temperature of molten metal in these equipment for holding molten metal, a method for measuring the batch temperature using a temperature probe has been proposed (see, for example, Patent Document 1). That is, Patent Document 1 discloses a temperature sampling device for a vacuum degassing apparatus in which, in the horizontal positioning of the temperature sampling, the temperature sampling probe can be safely raised and lowered in a narrow gap using the tank body as a guide.

[0003] Furthermore, as a technique for continuously measuring the temperature of molten metal, a method has been proposed in which a CCD camera is used to measure brightness from a tuyere provided at the bottom of a converter and convert the brightness into temperature (see, for example, Patent Document 2). That is, Patent Document 2 discloses a method for measuring the temperature of molten steel in a converter that ensures a field of view for measuring the molten steel temperature in the converter, makes it possible to continuously measure the molten steel temperature, and also makes it possible to suppress tuyere meltdown and extend the life of the tuyere.

[0004] Furthermore, as a method for monitoring the inside of a vacuum degassing tank, which is equipment for holding molten metal, a method has been proposed in which the addition of alloys or the falling of metals adhering to the inside of the tank is detected based on brightness information of an image of the inside of the tank taken by a camera installed at a position where the inside of the tank can be monitored (see, for example, Patent Document 3). That is, Patent Document 3 discloses a method in which the ratio of the area of ​​the part exceeding a preset brightness level to the entire image is calculated from the brightness information of an image of the inside of the vacuum degassing tank taken by an imaging device installed at the top of the vacuum degassing tank, and the addition of alloys or the falling of metals is automatically detected based on this ratio. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-207331 [Patent Document 2] JP 2007-322382 A [Patent Document 3] Japanese Patent Application Publication No. 7-150227 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional techniques have the following problems. That is, in the method of measuring the temperature of a batch of molten metal using a temperature measuring probe described in Patent Document 1, there is a problem that the temperature transition between measurements during the refining process of the molten metal is unknown. In addition, in the continuous temperature measuring technology using a camera described in Patent Document 2, the temperature measuring method of converting image brightness information into temperature has a problem that the exposure time needs to be constant during continuous temperature measurement because the detected brightness also changes when the exposure time of the camera is changed. Furthermore, in the method of monitoring the inside of a molten metal holding facility described in Patent Document 3, there is a problem that when ensuring the brightness of an image taken by the camera to check the inside of the facility, the exposure time needs to be changed according to the brightness of the image taken inside the facility. In addition, when a rotating disk with a slit is provided between the molten metal surface and the camera, there is a problem that it is not possible to obtain brightness information on the molten steel surface or monitor the inside of the molten metal holding facility unless the shutter is released at the timing when the rotating disk slit part passes through the field of view.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a continuous temperature monitoring technology in which an imaging unit such as a camera is installed in a position in a molten metal holding facility where the molten metal surface within the facility can be photographed, and the temperature of the molten metal is continuously measured from the brightness information of the image obtained by photographing the molten metal surface. [Means for solving the problem]

[0008] The molten metal temperature measuring and monitoring device of the present invention, which advantageously solves the above-mentioned problems, is a molten metal temperature measuring and monitoring device that is installed in equipment that holds molten metal and is capable of measuring the temperature of the molten metal and monitoring the condition within the equipment, and is characterized in that it comprises an imaging unit that is located above a monitoring imaging hole of the equipment and acquires an image of the molten metal surface within the equipment through the monitoring imaging hole, a turntable that is located below the monitoring imaging hole and has a slit that rotates at a constant rotational speed, a control unit that controls the timing at which the imaging unit acquires an image of the molten metal surface and the rotational speed of the turntable, and a calculation unit that calculates the temperature of the molten metal surface based on the image of the molten metal surface. Furthermore, it is considered that a more preferable solution would be for the molten metal temperature monitoring device of the present invention to further include a brightness adjustment unit that adjusts the brightness of the image of the molten metal while maintaining the exposure time of the imaging unit constant.

[0009] Furthermore, the present invention provides a molten metal temperature monitoring method, comprising the steps of: using the molten metal temperature monitoring device, acquiring an image of the molten metal surface by synchronizing the slit of the turntable to open the front of the field of view of the imaging unit at the timing when the imaging unit acquires an image of the molten metal; acquiring a brightness-adjusted image by adjusting the brightness of the molten metal image while maintaining a constant exposure time of the imaging unit; and calculating the temperature of the molten metal surface based on the brightness-adjusted image.

[0010] Furthermore, a computer program according to the present invention is a computer program used for implementing the molten metal temperature monitoring method, and is characterized in that it causes a computer to execute processes including a step of acquiring an image of the molten metal surface by synchronizing the slit of the turntable to open the front of the field of view of the imaging unit at the timing when the imaging unit acquires the image of the molten metal, a step of acquiring a brightness-adjusted image by adjusting the brightness of the image of the molten metal while maintaining the exposure time of the imaging unit constant, and a step of calculating the temperature of the molten metal surface based on the brightness-adjusted image. Effect of the Invention

[0011] According to the present invention, an imaging unit such as a camera is installed in a molten metal holding facility at a position where the molten metal surface inside the facility can be photographed, and the temperature of the molten metal can be continuously measured from the brightness information of the image obtained by photographing the molten metal surface. The molten metal temperature measuring and monitoring device according to the present invention is equipped with a turntable with a slit that is located below the monitoring imaging hole and rotates at a constant rotational speed, so that the molten metal circulating inside the facility will not splash onto the imaging unit such as a camera.

[0012] Furthermore, according to the present invention, gamma correction (image processing) can be performed on the images captured in the software while keeping the exposure time of the imaging unit such as the camera constant. Therefore, according to the present invention, it is possible to continuously measure the temperature of the molten metal surface and monitor the inside of the tank without the need for camera accessories such as a light-shielding lens for adjusting the brightness or the change in the calculated temperature of the molten metal that occurs due to the change in brightness information caused by changing the exposure time.

[0013] Furthermore, according to the present invention, by setting a turntable having a slit between the molten metal surface and the camera and setting the exposure time of an imaging unit such as a camera to a value correlated with the rotation period of the turntable, it is possible to release the shutter when the slit portion of the turntable passes through the field of view, thereby obtaining brightness information on the molten steel surface and monitoring the inside of the molten metal equipment. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a block diagram showing the configuration of a continuous molten metal temperature measuring device installed in an RH vacuum degassing vessel according to the present embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a continuous molten metal temperature measuring device installed in an RH vacuum degassing vessel according to the present embodiment. [Diagram 3] 3 is a schematic diagram showing the configuration of the peripheral equipment of the surveillance imaging hole provided in the RH vacuum degassing tank in which the continuous molten metal temperature measuring device according to the present embodiment is installed. Fig. 3(a) is a cross-sectional view showing the configuration of the peripheral equipment of the surveillance imaging hole, and Fig. 3(b) is a plan view showing the configuration of the peripheral equipment of the surveillance imaging hole. Fig. 3(c) is a schematic diagram showing the relationship between the slitted rotating disk constituting the peripheral equipment of the surveillance imaging hole and the imaging field of view of the imaging unit. [Figure 4] 1A and 1B are diagrams showing an image of the inside of a tank captured by a CCD camera during molten steel reflux treatment in an RH vacuum degassing equipment according to an embodiment of the present invention, a monitor output image after image gamma correction, and a molten steel temperature calculation flow using molten steel temperature calculation software. [Diagram 5] 4 is a graph showing the results of continuous measurement of the temperature of the molten metal in an RH vacuum degassing tank using the continuous molten metal temperature measuring device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The molten metal temperature monitoring device of this embodiment will be described below with reference to the drawings. Each drawing is a schematic diagram and may differ from the actual one. In addition, the following embodiment is an example of an apparatus and a method for embodying the technical idea of ​​the present invention, and the configurations thereof are not limited to those described below. In other words, the technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0016] [First embodiment] A molten metal temperature measuring and monitoring device 100 according to the first embodiment will be described. Here, the molten metal temperature measuring and monitoring device 100 according to the present invention can be adopted in any equipment capable of holding molten metal, such as a converter, an electric furnace, an RH vacuum degassing tank, a KR desulfurization equipment, a molten pig iron ladle, a molten metal ladle, a molten steel ladle, a tundish, etc. In this embodiment, a molten metal temperature measuring and monitoring device 100 installed when the equipment capable of holding molten metal is an RH vacuum degassing equipment will be described.

[0017] The molten metal temperature measuring and monitoring device according to the present embodiment is a molten metal temperature measuring and monitoring device that is installed in a facility that holds molten metal and is capable of measuring the temperature of the molten metal and monitoring the condition within the facility, and includes an imaging unit that is located above a monitoring imaging hole of the facility and obtains an image of the molten metal surface within the facility through the monitoring imaging hole; The present invention is directed to a molten metal temperature measuring device that is provided with a rotating disk having a slit located below the monitoring imaging hole and that rotates at a constant rotation speed, a control unit that controls the timing at which the imaging unit captures an image of the molten metal surface and the rotation speed of the rotating disk, and a calculation unit that calculates the temperature of the molten metal surface based on the image of the molten metal surface. Each of the components that constitute the molten metal temperature measuring device of this embodiment will be described below.

[0018] FIG. 1 is a block diagram showing the configuration of a continuous temperature measuring device 100 for molten metal installed in an RH vacuum degassing tank according to this embodiment. The continuous temperature measuring device 100 for molten metal includes an imaging unit 101 for acquiring an image of the molten metal surface in the facility and a rotating disk 102 with slits that has a disk shape and rotates at a constant rotation speed. The continuous temperature measuring device 100 for molten metal includes a control unit 103 for controlling the timing at which the imaging unit 101 acquires an image of the molten metal surface and the rotation speed of the rotating disk 102. The image of the molten metal surface acquired by the imaging unit 101 is transmitted to a calculation unit 104 for calculating the temperature of the molten metal. The calculation unit 104 detects the maximum brightness of the image of the molten metal surface acquired by the imaging unit 101 and calculates the temperature of the molten metal based on the maximum brightness. When the brightness of the image of the molten metal surface acquired by the imaging unit 101 is low, the brightness adjustment unit 105 adjusts the brightness of the image of the molten metal surface by performing gamma correction. The temperature of the molten metal calculated by the calculation unit 104 is output by an output unit 106. The image of the molten metal surface, whose brightness has been adjusted by the brightness adjustment unit 105, is output by the output unit .

[0019] FIG. 2 is a schematic diagram showing the configuration of a continuous molten metal temperature measuring device 100 installed in an RH vacuum degassing vessel according to this embodiment. As shown in FIG. 2, the molten metal temperature measuring and monitoring device 100 is composed of members installed inside and outside an RH vacuum degassing vessel 107, which is equipment capable of holding molten metal. A ladle 108 is attached to the lower part of the RH vacuum degassing vessel 107. Under a vacuum, the RH vacuum degassing vessel 107 and the ladle 108 are held in a vacuum, and molten metal 109 (hereinafter sometimes referred to as "molten steel 109") is held therein. The molten metal 109 circulates inside the RH vacuum degassing vessel 107 and the ladle 108. As the molten steel 109 circulates inside the ladle 108, unnecessary gas contained in the molten steel 109 is removed.

[0020] The molten metal temperature measuring and monitoring device 100 is provided with an imaging unit 101 that is located above a monitoring imaging hole 111 in the RH vacuum degassing vessel 107 and that obtains an image of a molten metal surface 112 of the molten metal 109 present in the RH vacuum degassing vessel 107 through the monitoring imaging hole 111. That is, the imaging unit 101 is installed above the monitoring imaging hole 111 provided in an upper lid 110 of the RH vacuum degassing vessel 107. The diameter of the monitoring imaging hole 111 can be determined taking into consideration its relative relationship with the effective aperture of a lens installed at the tip of the imaging unit 101.

[0021] The imaging unit 101 captures an image of the molten metal surface 112 present at the interface of the molten metal 109 present inside the RH vacuum degassing tank 107. The imaging unit 101 is not particularly limited as long as it is a member such as a measuring device that can convert the image of the molten metal surface 112 into an electric signal and extract it. The imaging unit 101 may be, for example, a device that can obtain brightness information of an object such as a CCD camera, a CMOS camera, a two-color thermometer, or a radiation thermometer, and among these devices, a CCD camera is particularly preferable. Examples of the CCD camera include an electronically cooled CCD camera, a liquid nitrogen CCD camera, and a CCD camera with an image intensifier. The imaging unit 101 installed above the monitoring imaging hole 111 of the RH vacuum degassing tank 107 may be composed of not only one but also multiple units.

[0022] The molten metal 109 circulates inside the RH vacuum degassing tank 107 and the ladle 108, thereby forming different molten metal surfaces 112 according to the progress of the degassing treatment. The imaging unit 101 acquires images of the different molten metal surfaces 112 formed according to the progress of the degassing treatment of the molten metal 109 at a predetermined timing. The imaging unit 101 acquires images of the molten metal surface 112 by photographing the molten metal surface 112. The images acquired by the imaging unit 101 by photographing the molten metal surface 112 are transmitted as image information through a wired LAN 113 to a calculation unit 104 that calculates the temperature of the molten metal surface 112. The images of the molten metal surface 112 transmitted to the calculation unit 104 are output to an in-facility monitoring monitor 114 connected to the calculation unit 104.

[0023] Here, when the imaging unit 101 captures an image of the molten metal surface 112, slag may be generated at the interface of the molten metal surface 112. When slag is generated at the interface of the molten metal surface 112, the molten metal surface 112 is not exposed to the surface of the molten metal 109, and therefore it is expected that the imaging unit 101 will not be able to capture an image of the molten metal surface 112 of the molten metal 109. However, even in such a case, if the RH reflux treatment is being performed, slag is not generated uniformly on the surface of the molten metal surface 112, and therefore the molten metal surface 112 is partially exposed, and an image of the exposed molten metal surface 112 can be captured.

[0024] The molten metal temperature measuring and monitoring device according to this embodiment includes a rotating disk with slits that is located below a monitoring imaging hole and rotates at a constant rotation speed. That is, the molten metal temperature measuring and monitoring device 100 includes a slitted rotating disk 102 located below a monitoring imaging hole 111. The slitted rotating disk 102 rotates around a rotating shaft 116 located adjacent to the monitoring imaging hole 111 of the RH vacuum degassing tank 107 as its central axis. The rotating shaft 116 may be a driving rotating shaft driven by the rotating shaft 116 itself, or may be a driven rotating shaft that is linked to another driving rotating shaft.

[0025] Fig. 3 is a schematic diagram showing the configuration of the peripheral equipment of a surveillance imaging hole 111 provided in an RH vacuum degassing tank 107 in which a continuous molten metal temperature measuring device 100 according to this embodiment is installed. Fig. 3(a) is a cross-sectional view showing the configuration of the peripheral equipment of the surveillance imaging hole 111, Fig. 3(b) is a plan view showing the configuration of the peripheral equipment of the surveillance imaging hole 111, and Fig. 3(c) is a schematic diagram showing the relationship between a slitted turntable constituting the peripheral equipment of the surveillance imaging hole and the imaging field of view of the imaging unit.

[0026] As shown in FIG. 3(a), a surveillance imaging hole 111 is provided in the top cover 110 of the RH vacuum degassing tank 107. Peripheral equipment is provided around the surveillance imaging hole 111. The peripheral equipment includes the surveillance imaging hole 111 and the slitted turntable 102. Inside the surveillance imaging hole 111, two glass plates 117 are provided, which are a glass plate 117a on the imaging unit 101 side that forms the upper surface of the surveillance imaging hole 111, and a glass plate 117b on the slitted turntable 102 side that forms the lower surface of the surveillance imaging hole 111. The two glass plates 117 are fixed in the surveillance imaging hole 111 by being fitted into a recess 118 in the wall provided in the hole of the surveillance imaging hole 111. Furthermore, a sealing O-ring 119 is interposed between the glass plate 117a and the glass plate 117b that constitute the two glass plates 117. The monitoring imaging hole 111 captures an image of the molten metal surface 112 in the RH vacuum degassing tank 107 through two glass plates 117. Here, the planar shape of the monitoring imaging hole 111 is preferably a circle with a diameter within the range of the length of the slit 124 in the slitted turntable 102. The shape of the glass plate 117 is preferably a circle with the same diameter as the monitoring imaging hole 111 (Φ50 to 200 mm), for example. The thickness of the glass plate 117 is preferably 5 to 30 mm, for example. The thickness of the sealing O-ring 119 is preferably 2.0 to 3.0 mm, for example.

[0027] As shown in FIG. 3(b), the slitted rotating disk 102 is located below the surveillance imaging hole 111 and faces the glass 117b provided in the hole of the surveillance imaging hole 111. The disk 120 constituting the slitted rotating disk 102 is circular and made of a disk-shaped member having a predetermined thickness. The slitted rotating disk 102 is made of a heat-resistant material such as a heat-resistant metal material or ceramics. The slitted rotating disk 102 located below the surveillance imaging hole 111 is rotated at a predetermined rotation speed in a predetermined direction by a rotation driving force of a driving rotating shaft 121 such as a motor being transmitted to a rotating shaft (driven rotating shaft) 123 via a belt 122. As a result, the slitted rotating disk 102 rotates around the rotating shaft (driven rotating shaft) 123. The rotation direction and the number of rotations of the slitted rotating disk 102 are determined by the rotation driving force of the rotating shaft (driven rotating shaft) 123. The rotational driving force of the rotating shaft (driven rotating shaft) 123 is controlled by a control unit 103 provided in the molten metal temperature measuring and monitoring device 100. The rotation status of the slitted turntable 102 controlled by the control unit 103 can be monitored by an operation panel monitor 115 connected to the driving rotating shaft 121 by a wired LAN or the like.

[0028] The slitted turntable 102 has one or more slits 124. The number of slits 124 is not particularly limited, but is preferably 2 to 8. When the slitted turntable 102 has multiple slits 124, these multiple slits 124 are preferably provided at opposing positions within the plane of the slitted turntable 102. If the number of slits 124 is two or more, this is preferable because the camera exposure time can be shortened. If the number of slits 124 is eight or less, this is preferable because dust scattering into the monitoring hole can be prevented.

[0029] 3(c) is a schematic diagram showing the relationship between the slitted turntable constituting the peripheral equipment of the surveillance imaging hole and the imaging field of view of the imaging unit. The slitted turntable 102 is located below the surveillance imaging hole 111 and faces the glass plate 117b provided in the surveillance imaging hole 111. Therefore, the imaging unit 101 installed above the surveillance imaging hole 111 can form an imaging field of view 125 of the imaging unit 101 in the range where the surveillance imaging hole 111 and the slits 124 of the slitted turntable 102 overlap. The imaging unit 101 can capture an image of the molten metal surface 112 of the molten metal 109 present inside the RH vacuum degassing tank 107.

[0030] On the other hand, the imaging unit 101 installed above the monitoring imaging hole 111 cannot form an imaging field of view 125 of the imaging unit 101 in a range where the monitoring imaging hole 111 and the slits 124 of the slitted turntable 102 do not overlap. Therefore, the imaging unit 101 cannot capture an image of the molten metal surface 112 of the molten metal 109 present inside the RH vacuum degassing tank 107. In this way, the molten metal temperature measuring and monitoring device 100 of this embodiment is provided with the slitted turntable 102 that can rotate about the rotation axis 116 located adjacent to the monitoring imaging hole 111 of the RH vacuum degassing tank 107, thereby forming a state in which an image of the molten metal surface 112 of the molten metal 109 can be captured and a state in which an image of the molten metal surface 112 of the molten metal 109 cannot be captured.

[0031] The molten metal temperature measuring and monitoring device according to this embodiment includes a control unit that controls the timing at which the imaging unit captures an image of the molten metal surface and the rotation speed of the turntable. That is, the molten metal temperature measuring and monitoring device 100 includes a control unit 103 that controls the timing at which the imaging unit 101 captures an image of the molten metal surface 112 of the molten metal 109 and the rotation speed of the slit turntable 102. The control unit 103 controls the rotation period n of the slit turntable 102. The control unit 103 recognizes the number A of slits 124 that the slit turntable 102 has. Then, the control unit 103 determines the exposure time [seconds] of the imaging unit 101 based on the rotation period n of the slit turntable 102 and the number A of slits 124 that the slit turntable 102 has. The exposure time [seconds] of the imaging unit 101 is calculated and determined by the following general formula (1).

[0032]

number

[0033] In the above general formula (1), n ​​is the rotation period of the slitted rotating disk, A is the number of slits provided on the slitted rotating disk, N is an integer, and α is a correction value. Here, N and α each independently represent the minimum value among the values ​​that change the γ value in the range of 0.75≦γ≦3.0 to obtain a monitor output brightness that allows the inside of the tank to be confirmed. In this way, the control unit 103 provided in the molten metal temperature measuring and monitoring device 100 according to this embodiment minimizes the extension of the exposure time of the imaging unit 101 by setting N to the minimum value in the above general formula (1) when setting the exposure time [seconds] of the imaging unit 101.

[0034] In this way, the control unit 103 sets the exposure time of the imaging unit 101 to a constant value, thereby enabling the imaging unit 101 to capture the molten metal surface 112 at the timing when the slits 124 of the slitted turntable 102 pass through the imaging field of view of the imaging unit 101. The technical significance of the control unit 103 matching the rotation period of the slitted turntable 102 and the exposure time [seconds] of the imaging unit 101 is as follows.

[0035] That is, an open portion of the imaging field of the imaging unit 101 due to the slits 124 of the slit turntable 102 and a closed portion of the imaging field of the imaging unit 101 due to the parts of the slit turntable 102 other than the slits 124 periodically appear within the imaging range of the imaging unit 101. Therefore, the amount of light collected by the imaging unit 101 during the exposure time attenuates the image brightness of the molten metal surface 112. As a result, the image brightness of the molten metal surface 112 captured by the imaging unit 101 is not stable, and the imaging unit 101 cannot capture the maximum brightness of the image of the molten metal surface 112. In other words, measurement errors are likely to occur in the temperature of the molten metal surface 112 continuously measured by the molten metal temperature measuring and monitoring device 100 of this embodiment.

[0036] Furthermore, when the exposure time of the imaging unit 101 is extended by setting the exposure time longer than a predetermined exposure time, the amount of collected light during the exposure of the imaging unit 101 is over-accumulated. Therefore, the brightness of the image of the molten metal surface 112 diverges, and the imaging unit 101 cannot obtain an accurate brightness of the image of the molten metal surface 112. As a result, the imaging unit 101 cannot obtain the maximum brightness of the image of the molten metal surface 112. In other words, the molten metal temperature measuring and monitoring device 100 of this embodiment cannot continuously measure the temperature of the molten metal surface 112.

[0037] Furthermore, the molten metal temperature measuring and monitoring device according to this embodiment includes a calculation unit that calculates the temperature of the molten metal surface based on an image of the molten metal surface. That is, the calculation unit 104 included in the molten metal temperature measuring and monitoring device 100 calculates the temperature T [°C] of the molten metal surface 112 (hereinafter, also referred to as "molten steel temperature T [°C]") based on the maximum brightness of the image of the molten metal surface 112 captured by the imaging unit 101. The calculation unit 104 detects the brightness of the image of the molten metal surface 112 acquired by the imaging unit 101 capturing the image of the molten metal surface 112. That is, the calculation unit 104 detects the brightness of the molten metal surface 112 of the molten metal 109 present inside the RH vacuum degassing tank 107. The calculation unit 104 identifies the maximum brightness in the acquired image of the molten metal surface 112 based on brightness information of the image.

[0038] The calculation unit 104 is provided with molten steel temperature calculation software, and detects the maximum brightness I[-] from the brightness information of the image of the molten metal surface 112 acquired by the imaging unit 101 using the molten steel temperature calculation software. The calculation unit 104 calculates the molten steel temperature T[°C] by converting the maximum brightness I[-] into temperature using a predetermined linear function. Here, the maximum brightness I[-] of the molten metal surface 112 is defined as the maximum brightness in the image obtained by the imaging unit 101 capturing the molten metal surface 112 in the RH vacuum degassing tank 107 through the monitoring imaging hole 111 and the slits 124 of the slitted turntable 102 during a set predetermined exposure time. The molten steel temperature T[°C] is calculated by the following general formula (2).

[0039]

number

[0040] In the above general formula (2), I[-] is the maximum brightness in the captured image obtained by capturing an image of the molten metal surface, and the values ​​of the predetermined coefficients a and b are coefficients used when processing the molten metal in the equipment that holds the molten metal, and are coefficients determined empirically for each type of molten metal holding equipment, for example. Note that the value of the predetermined coefficient a can be appropriately set depending on the processing conditions of the molten metal, but since the brightness increases as the molten steel temperature T [°C] increases, it is preferable that a>0.

[0041] [Second embodiment] The molten metal temperature measuring and monitoring device according to the second embodiment will be described. That is, the molten metal temperature measuring and monitoring device 100 according to this embodiment is characterized in that it further includes a brightness adjustment unit 105 that adjusts the brightness of the image of the molten metal surface while maintaining the exposure time of the imaging unit constant in the above-mentioned molten metal temperature measuring and monitoring device 100. The brightness adjustment unit 105 included in the molten metal temperature measuring and monitoring device 100 according to this embodiment applies gamma correction (image processing) to the image of the molten metal surface 112 transmitted from the imaging unit 101. The brightness adjustment unit 105 applies gamma correction (image processing) to the molten metal image 112, thereby obtaining an image output value D[-] after gamma correction. The image output value D[-] after gamma correction can be calculated by the following general formula (3).

[0042]

number

[0043] As shown in the above general formula (3), the image output value D[-] after gamma correction can be calculated by the product of the input light amount E[-] and the correction value γ[-]. In the above general formula (3), the input light amount E[-] represents the input light amount [-] in the image, and the correction value γ[-] represents the correction value used when applying gamma correction (image processing). Here, the correction value γ used when applying gamma correction (image processing) to the captured image is preferably 0.75≦γ≦3.0. If the correction value γ is 0.75 or more, the monitor brightness is not too dark and the inside of the tank can be seen, which is preferable. If the correction value γ is 3.0 or less, the monitor brightness is not too bright and the inside of the tank can be seen, which is preferable.

[0044] For example, when the brightness of the image of the molten metal surface 112 transmitted from the image capturing unit 101 and output to the monitor of the brightness adjusting unit 105 is low, the brightness adjusting unit 105 increases the correction value γ with respect to the brightness (input light amount). On the other hand, when the brightness of the image of the molten metal surface 112 is high, the brightness adjusting unit 105 decreases the correction value γ. In this way, the brightness adjusting unit 105 provided in the molten metal temperature measuring and monitoring device 100 according to this embodiment can change the monitor output brightness of the image of the molten metal surface 112 of the image capturing unit 101 while keeping the exposure time of the image capturing unit 101 constant. In other words, the molten metal temperature measuring and monitoring device 100 according to this embodiment can monitor the state inside the facility that holds the molten metal by capturing an image at any brightness.

[0045] As described above, according to the molten metal temperature measuring and monitoring device of the second embodiment, by adjusting the brightness of the image of the molten metal, it is possible to continuously measure the temperature of the molten metal and monitor the inside of the tank without the need for camera accessories such as a light-shielding lens.

[0046] [Third embodiment] A molten metal temperature monitoring method according to the third embodiment will be described. That is, this embodiment is a molten metal temperature monitoring method using the above-mentioned molten metal temperature monitoring device. The molten metal temperature monitoring method according to this embodiment is characterized by including: (a) a step of acquiring an image of the molten metal surface by synchronizing the slits of the slitted turntable so as to open the front of the field of view of the imaging unit at the timing when the imaging unit acquires the image of the molten metal surface; (b) a step of acquiring a brightness-adjusted image by adjusting the brightness of the molten metal image while maintaining the exposure time of the imaging unit constant; and (c) a step of calculating the temperature of the molten metal surface based on the brightness-adjusted image. Each step included in the molten metal temperature monitoring method according to this embodiment will be described below.

[0047] (A process for acquiring an image of the molten metal surface) The molten metal temperature measuring and monitoring method of this embodiment includes a step of acquiring an image of the molten metal surface. That is, the step of acquiring an image of the molten metal surface is a step of acquiring an image of the molten metal surface 112 of the molten metal 109 present inside the RH vacuum degassing tank 107 using the above-mentioned molten metal continuous temperature measuring device. The step of photographing the image of the molten metal surface 112 is performed by synchronizing the timing at which the imaging unit 101 photographs the molten metal surface 112 with the slits 124 of the slitted turntable 102 so as to open the front of the field of view of the imaging unit 101. That is, the control unit 103 synchronizes the timing at which the imaging unit 101 photographs the molten metal surface 112 with the slits 124 of the slitted turntable 102 so as to open the front of the field of view of the imaging unit 101.

[0048] In the process of acquiring an image of the molten metal surface 112, the control unit 103 recognizes the number A of slits 124 in the slitted turntable 102. The control unit 103 determines the exposure time of the imaging unit 101 based on the rotation period n of the slitted turntable 102 and the number A of slits 124. The exposure time [seconds] of the imaging unit 101 is calculated and determined by the following general formula (1).

[0049]

number

[0050] In the above general formula (1), n ​​is the rotation period of the slitted rotating disk, A is the number of slits provided in the slitted rotating disk, N is an integer, and α is a correction value, each of which independently represents the minimum value among the values ​​within the range of 0.75≦γ≦3.0 at which the γ value is changed and the monitor output brightness becomes such that the inside of the tank can be observed.

[0051] In this way, in the process of acquiring an image of the molten metal surface 112, the control unit 103 sets the exposure time of the imaging unit 101, so that the imaging unit 101 can capture an image of the molten metal surface 112 (for example, a CCD camera or the like can release the shutter) at the timing when the slits 124 of the slitted turntable 102 pass through the imaging field of view of the imaging unit 101.Based on the captured image of the molten metal surface 112, brightness information of the molten metal surface 112 can be obtained and the inside of the equipment holding the molten metal can be monitored.

[0052] (Step of obtaining brightness-adjusted image) Next, the molten metal temperature measurement and monitoring method of this embodiment includes a step of acquiring a brightness-adjusted image. The step of acquiring a brightness-adjusted image is a step of applying gamma correction to the image acquired in the step of photographing the image of the molten metal surface 112. Furthermore, the step of acquiring a brightness-adjusted image acquires the brightness-adjusted image by adjusting the brightness of the image of the molten metal surface 112 acquired in the above step while maintaining a constant exposure time. The brightness-adjusted image is acquired by applying gamma correction (image processing) to the video image photographed in software in the step of acquiring the image of the molten metal surface 112.

[0053] In the process of acquiring the brightness-adjusted image, the brightness adjustment unit 105 applies gamma correction (image processing) to the image of the molten metal surface 112 transmitted from the imaging unit 101. The brightness adjustment unit 105 applies gamma correction (image processing) to the image of the molten metal surface 112, thereby obtaining an image output value D[-] after gamma correction. The image output value D[-] after gamma correction can be calculated by the following general formula (3).

[0054]

number

[0055] That is, the image output value D[-] after gamma correction can be calculated by the product of the input light amount E[-] and the correction value γ[-]. In the above general formula (3), the input light amount E[-] represents the input light amount [-] in the image, and the correction value γ[-] represents the correction value used when applying gamma correction (image processing). Here, the correction value γ used when applying gamma correction (image processing) to the captured image is preferably 0.75≦γ≦3.0. If the correction value γ is 0.75 or more, the monitor brightness is not too dark and the inside of the tank can be seen, which is preferable. If the correction value γ is 3.0 or less, the monitor brightness is not too bright and the inside of the tank can be seen, which is preferable.

[0056] In the step of acquiring the brightness-adjusted image, if the brightness of the tank image output to the tank interior monitor 114 provided in the calculation unit 104 is low, the correction value γ is increased with respect to the brightness (input light amount). On the other hand, in the step of acquiring the image of the molten metal surface, if the brightness of the tank interior image is high, the correction value γ is decreased with respect to the brightness (input light amount). Thus, in the step of acquiring the brightness-adjusted image in the molten metal temperature monitoring method according to this embodiment, the correction value γ is changed according to the brightness of the image of the molten metal surface 112, thereby changing the output brightness of the tank interior monitor of the image of the molten metal surface 112 of the image capturing unit 101 while keeping the exposure time of the image capturing unit 101 constant. In other words, the molten metal temperature monitoring method according to this embodiment can monitor the state inside the facility that holds the molten metal by using an image captured at any brightness.

[0057] (Process for calculating the temperature of the molten metal surface) Furthermore, the molten metal temperature measurement and monitoring method according to this embodiment includes a step of calculating the temperature of the molten metal surface. The step of calculating the temperature of the molten metal surface calculates the temperature of the molten metal surface (molten steel temperature T [°C]) from a brightness-adjusted image that has been subjected to brightness adjustment. The molten steel temperature T [°C] can be calculated by converting the maximum brightness of the brightness information of the captured image into temperature using a linear function using software provided in the calculation unit 104. The molten steel temperature T [°C] is calculated and determined using the following general formula (2).

[0058]

number

[0059] In the above general formula (2), I[-] is the maximum brightness in the captured image obtained by capturing an image of the molten metal surface, and the values ​​of the predetermined coefficients a and b are coefficients used when processing the molten metal in the equipment that holds the molten metal, and are coefficients determined by empirical rules. Note that the value of the predetermined coefficient a can be appropriately set depending on the processing conditions of the molten metal, but since the brightness increases as the molten steel temperature T [°C] increases, it is preferable that a>0.

[0060] In the molten metal temperature measurement and monitoring method according to the present embodiment, in the step of acquiring a brightness-adjusted image, it is preferable to use a correction value γ used in gamma correction (image processing) of, for example, any value between γ=1.8 and 2.4, and to continuously measure the temperature of the molten metal with a monitor brightness that allows the inside of the tank to be confirmed. In addition, in the step of calculating the temperature of the molten metal surface, when calculating the molten steel temperature T [°C] from the luminance inside the tank, it is preferable to use a linear function of T=a×I+b using the maximum luminance I [-] in the captured image and coefficients a and b. Specifically, in the molten metal temperature measurement method according to the present embodiment, coefficients a=0.400 and b=1446.4, and the molten steel temperature T [°C] can be calculated from the maximum luminance inside the tank by the molten steel temperature calculation software provided in the calculation unit 104.

[0061] As described above, according to the method for measuring and monitoring the temperature of molten metal in the third embodiment, the temperature of the molten metal can be continuously measured from brightness information obtained by photographing the molten metal surface. Furthermore, according to the method for measuring and monitoring the temperature of molten metal in the third embodiment, an image of the molten metal surface can be acquired at the timing when the slits of the slitted turntable pass through the field of view of the imaging unit, and brightness information on the molten metal surface can be acquired and the inside of the molten metal facility can be monitored.

[0062] [Fourth embodiment] A computer program according to the fourth embodiment will be described. That is, the computer program according to this embodiment is a computer program used to implement the molten metal temperature monitoring method according to the above embodiment. That is, the computer program according to this embodiment can also be realized as a program describing the processing contents for realizing each function of the molten metal temperature monitoring device according to the above embodiment, or a storage medium having a program recorded thereon. Therefore, it should be understood that these are also included in the technical scope of the present invention.

[0063] The computer program of the present embodiment may be supplied directly or remotely to a system or device. Therefore, a program installed on a computer to realize the above-mentioned embodiment of the present invention by a computer, a medium storing the program, and a WWW (World Wide Web) server from which the program can be downloaded are also included in the technical scope of the present invention. Furthermore, a non-transitory computer-readable medium storing a program for causing a computer to execute the processing steps for implementing the molten metal temperature monitoring method of the above-mentioned embodiment is also included in the technical scope of the present invention.

[0064] As described above, the computer program of this embodiment is configured to realize each step of the molten metal temperature monitoring method of the above embodiment, so that the temperature of the molten metal can be continuously measured from the brightness information of the molten metal obtained by photographing the molten metal surface, and the inside of the tank can be monitored using an image of the molten metal surface with adjusted brightness.

[0065] [Other embodiments] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above embodiment. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the technical scope of the present invention. EXAMPLES

[0066] An example of measuring the temperature of molten metal in a vacuum degassing tank using the molten metal temperature measuring and monitoring device according to the present invention is shown below. In this example, a vacuum degassing tank was used to process 280 to 350 tons of molten steel from a ladle, and the results of continuous temperature measurement of the molten metal during reflux treatment of molten steel at a temperature of 1620 to 1700°C for 10 to 50 minutes are shown.

[0067] FIG. 4 shows a monitor output image 127 before gamma correction of the captured image 126 of the inside of the tank taken by the CCD camera during the molten steel reflux process, and a monitor output image 128 after gamma correction of the captured image. As is clear from FIG. 4, the brightness of the CCD camera captured image 127 of the inside of the tank taken by the CCD camera during the molten steel reflux process is low, whereas the brightness of the CCD camera captured image 128 after gamma correction of the captured image is high. As shown in FIG. 4, the molten steel temperature T [°C] is calculated from the maximum brightness in the tank by the molten steel temperature calculation software provided in the calculation unit 104. Specifically, in this embodiment, a linear function of T=a×I+b is used using the maximum brightness I[-] and coefficients a and b, with a set of a=0.400 and b=1446.4, and the molten steel temperature T [°C] is calculated from the maximum brightness 129 in the tank by the molten steel temperature calculation software.

[0068] Furthermore, a slitted turntable with a rotation frequency of n=25[Hz] and number of slits A=4 was provided below the monitoring imaging hole provided between the molten steel surface and the CCD camera of the molten metal temperature measuring and monitoring device used in this example. The shutter of the CCD camera was released when the slit part of the slitted turntable passed through the imaging field of view. Here, the exposure time of the CCD camera was calculated using the above general formula (3). In the above general formula (3), N=2, α=420×10 -6 The exposure time was not changed during the molten steel reflux process, and the temperature of the molten steel was continuously measured and the condition inside the vessel was monitored.

[0069] FIG. 5 is a graph showing the results of continuous temperature measurement of molten metal during molten steel reflux treatment, when the molten metal temperature measuring device according to the present invention is installed in a vacuum degassing facility. As shown in FIG. 5, the results of continuous temperature measurement of molten metal are shown as measured values ​​of molten steel temperature T [°C] (vertical axis) versus elapsed time [min] (horizontal axis). In FIG. 5, the continuous temperature measurement of molten metal was performed at a rate of 60 plots / min, with one plot (temperature measurement) per second, and the average value of five intervals was calculated as the average value for five seconds, and then displayed as a broken line. As is clear from FIG. 5, it was found that continuous temperature measurement of molten metal was possible when the molten steel temperature T [°C] was in the range of 1580 to 1595°C. That is, the molten metal temperature measuring device according to the present invention was able to continuously measure the temperature of molten metal during molten steel reflux treatment in the vacuum degassing facility.

[0070] In this way, by using the molten metal temperature measuring and monitoring device of the present invention, the temperature of the molten metal can be continuously measured from the brightness information obtained by photographing the molten metal surface, and the situation inside the equipment can be monitored with adjusted brightness. [Industrial Applicability]

[0071] The molten metal temperature measuring and monitoring device of the present invention can continuously measure the temperature of the molten metal from the brightness information obtained by photographing the molten metal surface, and can perform gamma correction (image processing) on ​​the images taken within the software while keeping the camera exposure time constant. This makes it possible to perform continuous temperature measurement and monitoring inside the tank without the need for camera accessories such as light-shielding lenses, making it extremely useful in industries such as the steelmaking industry. [Explanation of symbols]

[0072] 100 Molten metal temperature measuring and monitoring device 101 Imaging unit 102 Slotted Turntable 103 Control section 104 Calculation section 105 Brightness adjustment section 106 Output section 107 RH vacuum degassing tank 108 Ladle 109 Molten Metal 110 Top lid 111 Surveillance and imaging hole 112 Molten metal surface 113 Wired LAN 114 Facility monitoring monitor 115 Operation panel monitor 116 Rotating shaft (driven rotating shaft) 117 Glass Plate 117a Glass plate 117b Glass plate 118 Wall recess 119 Sealing O-ring 120 Disc 121 Drive shaft 122 Belt 123 Driven Rotary Shaft 124 Slit 125 imaging field 126 Image of inside the tank taken with a CCD camera 127 Monitor output image of molten metal surface before gamma correction 128 Monitor output image of molten metal surface after gamma correction 129 Maximum brightness point in the image captured by the CCD camera

Claims

1. A molten metal temperature measuring and monitoring device that is installed in a facility for holding molten metal and is capable of measuring the temperature of the molten metal and monitoring the condition within the facility, an imaging unit located above a monitoring imaging hole of the facility and capturing an image of a molten metal surface in the facility through the monitoring imaging hole; a rotating disk having a slit located below the surveillance imaging hole and rotating at a constant rotation speed; a control unit that controls a timing when the imaging unit captures an image of the molten metal surface and a rotation speed of the turntable; a calculation unit that detects a maximum brightness among brightness information of the image of the molten metal surface and continuously calculates a temperature of the molten metal surface based on the maximum brightness, the control unit synchronizes a rotation period of the rotating disk having the slit with an exposure time of the imaging unit, A molten metal temperature measuring and monitoring device further comprising a brightness adjustment unit that adjusts the brightness of the image of the molten metal while maintaining the exposure time of the imaging unit constant.

2. Using the molten metal temperature measuring and monitoring device according to claim 1, acquiring an image of the molten metal surface by synchronizing the slit of the rotating disk so as to open a front portion of a field of view of the imaging unit at a timing when the imaging unit acquires an image of the molten metal; a step of acquiring a brightness-adjusted image by adjusting the brightness of the image of the molten metal while maintaining the exposure time of the imaging unit constant; and calculating a temperature of the molten metal surface based on the brightness-adjusted image.

3. A computer program used to implement the molten metal temperature monitoring method according to claim 2, acquiring an image of the molten metal surface by synchronizing the slit of the rotating disk so as to open a front portion of a field of view of the imaging unit at a timing when the imaging unit acquires an image of the molten metal; a step of acquiring a brightness-adjusted image by adjusting the brightness of the image of the molten metal while maintaining the exposure time of the imaging unit constant; and calculating a temperature of the molten metal surface based on the brightness-adjusted image.

Images