JP2008096298A - Method and device for measuring blast furnace charging material profile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for measuring a three-dimensional charging material profile of a blast furnace from temperature pattern information of a charging material layer upper surface by a pair of infrared cameras arranged on the top of the blast furnace. <P>SOLUTION: A method and device for measuring the blast furnace charging material profile are described as follows: a pair of two-dimensional temperature pattern detectors using infrared cameras for receiving infrared light from the whole surface of charging materials in the blast furnace are arranged in the blast furnace; each temperature pattern information of the charging material upper surface at the same time from different directions is acquired; a characteristic part on an isothermal line is determined on two-dimensional temperature patterns of both detectors; an optional point P on the characteristic part is selected; a three-dimensional position of the point P is calculated from comparison of the position of the point P in images of both detectors; and the shape of the charging material layer upper surface in the blast furnace is drawn from position information of a plurality of characteristic parts. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for measuring the shape of an upper surface of a charge layer in a blast furnace shaft (hereinafter referred to as a charge profile) by information from an infrared camera disposed on the top of the furnace.

The blast furnace charge profile meter is used to control the charging of raw materials and the flow of gas in the furnace, and is an indispensable means for blast furnace operation management and facility maintenance.
The blast furnace charge profile meter is roughly classified into a contact type (mechanical type) and a non-contact type. Traditionally, various efforts have been made to develop better charge profilometers. For example, in the non-contact type, measurement by laser radar and sonic radar has been attempted, but the quality of the signal is poor due to high temperature and high dust inside the furnace, and the development of a device that can withstand harsh environments for a long time has been developed. It is difficult and none has been put into practical use.

At present, a microwave method (for example, Patent Document 1 below) is mainly used, and a contact type (a mechanical type such as a sounding rod method) is also used in part.
In the microwave method, a large microwave probe is inserted into the upper space of the furnace, and the irradiation profile is measured by scanning the irradiation microwave on a specific line. Although this method has an advantage that the attenuation of the microwave is small even with high-concentration dust, the apparatus is large and expensive, the measurement operation is complicated, and it can be used only several times a day.
On the other hand, in order to perform multi-point measurement, the mechanical type requires a long measurement time and easily causes a failure in the mechanical system due to the influence of dust in the furnace, which causes a problem in maintenance management.

  In view of the problems of the prior art as described above, the charge profilometer is a non-contact measurement method, hardly affected by high-concentration dust in the furnace, the device is small and inexpensive, Since the measurement time is short and time-consuming, it is preferable that information on the charge profile can be obtained almost continuously.

Therefore, the present inventors have focused on obtaining information on the charge profile by measuring the intensity or surface temperature of infrared rays generated from the charge surface by a night vision (infrared) camera.
The problems with this infrared camera system are, first of all, how to obtain the information of the three-dimensional charge profile from the information of the camera that observes the charge surface in two dimensions. Secondly, how to protect the camera lens from the furnace gas atmosphere with extremely high dust and mist concentration.

As for the former, by finding infrared intensity (temperature) information of the charge surface from different directions by a pair of infrared camera methods, we found that it can be realized by an analysis method that extended the principle of triangulation, The present invention has been completed.
Regarding the latter, for example, the following Patent Document 2 discloses a “TV camera device for dark place photography”. This is for lighting and photographing inside the furnace through a small hole for illumination and a small hole for photographing provided on the furnace wall. A partition with a small hole is placed at the focal position of the illumination or photographing lens, and the lens side A small amount of gas is ejected through this hole to secure the optical path, or a small hole is covered with glass and a small area hitting the optical path is purged from the opposite side of the lens to prevent contamination of the range surface or glass surface It is.
This method has a problem that if the hole diameter is large, the amount of purge gas required becomes excessive, and if the hole diameter is small, it is difficult to observe the entire interior of the furnace at a wide angle.

  Therefore, the first object of the present invention is to make it possible to measure the three-dimensional charge profile of the blast furnace from the temperature pattern information on the upper surface of the charge layer by a pair of infrared cameras. Charge profile that is almost unaffected by high-concentration dust, is small and inexpensive, has a short measurement time, and does not require much effort, so it can obtain information on the charge profile almost continuously. To provide a meter.

  A second object of the present invention is to provide means capable of observing the inside of the furnace at a wide angle without increasing the amount of purge gas when using purge gas to prevent contamination of the camera lens. .

Japanese Utility Model Publication No. 1-2216 JP-A-5-88094

The method for measuring the blast furnace charge profile of the present invention to solve the above problems is as follows.
A pair of infrared cameras provided with a two-dimensional light-receiving sensor that is arranged on the furnace shoulder of the blast furnace and receives infrared light from almost the entire top surface of the furnace interior, and detects the intensity of the infrared light. A temperature pattern detector that creates a three-dimensional temperature pattern is placed in a pair of blast furnaces, and information on the temperature pattern of the upper surface of the furnace interior is observed from different directions at the same time,
In the two-dimensional temperature pattern of both detectors, a characteristic curve having a common characteristic is defined, an arbitrary point P on the characteristic curve is selected, and the point P is compared with the position of the point P in the images of the two detectors. Calculate the three-dimensional position of P,
A method for measuring a blast furnace charge profile, wherein a shape of an upper surface of a charge layer in a furnace is plotted from position information of a plurality of characteristic curves.

  In the above measurement method, the characteristic portion C1 of the isotherm image is determined from the two-dimensional temperature pattern of one of the detectors (hereinafter referred to as the first detector), an arbitrary point P on the isotherm image C1 is selected, A straight line L extending in the direction of the point P from the optical reference point (principal point of the objective lens) O of one detector is assumed, and the C1 obtained by the other detector (hereinafter referred to as the second detector) is assumed to be C1. The image of the virtual straight line L is superimposed on the image of the corresponding feature portion C2, the length of the virtual straight line L is changed, and the virtual straight line when the L intersects the feature partial image C2 on the second detector. By giving the positional relationship between the first detector and the corresponding point P on the charging surface by L (by the length of L when the L is in contact with C2), the three-dimensional position of the point P is determined. It may be calculated.

The apparatus for measuring the blast furnace charge profile of the present invention is:
A pair of infrared cameras provided with a two-dimensional light-receiving sensor that is arranged on the furnace shoulder of the blast furnace and receives infrared light from almost the entire top surface of the furnace interior, and detects the intensity of the infrared light. A feature portion C1 of an isotherm image is determined from a pair of temperature pattern detectors for creating a two-dimensional temperature pattern and a two-dimensional temperature pattern of the first detector, an arbitrary point P on the isotherm image C1 is selected, A straight line L extending from the optical reference point O of the detector in the direction of the point P is assumed, and an image of the characteristic portion C2 corresponding to C1 obtained by the other detector (hereinafter referred to as a second detector) is obtained. The virtual straight line L is overlapped, the length of the virtual straight line L is changed, and the virtual straight line L when the L intersects the feature partial image C2 on the second detector (the L becomes C2). (Depending on the length of L when touching) And position calculating means for determining the position of P,
It is characterized by comprising drawing means for drawing the shape of the upper surface of the charge layer in the furnace from the positional information of the plurality of characteristic portions.

In the above-described measuring apparatus, a through-hole communicating with the blast furnace iron shell and its lower refractory is provided at the mounting position of the infrared camera, and a ball valve is disposed outside the through-hole of the iron shell in close proximity thereto. Established,
A partition wall having a small-diameter viewing hole is provided in the center of the ball valve near the inner end of the through hole in the ball,
And the objective lens system of the camera is disposed in the inside of the ball penetration part in the vicinity of the rear surface of the partition wall so that the optical axis thereof passes through the center of the viewing hole, and infrared light from the objective lens system is transmitted. And is configured to enter the two-dimensional light receiving sensor via an optical system as necessary,
It is preferable that the purge gas can be circulated from the back surface to the inside of the furnace through the viewing hole.

  With this configuration, the objective lens system can be arranged in the immediate vicinity of the back surface of the partition wall provided in the penetrating portion of the ball valve, and the inside of the blast furnace can be It will be observable. Since the diameter of the viewing hole of the partition wall can be reduced, the flow rate of the purge gas passing therethrough can be reduced. In an emergency, if the ball of the ball valve is rotated, the optical system of the infrared camera can be completely cut off from the furnace atmosphere, and the lens and the like can be easily protected.

In this measuring apparatus, a cover is provided outside the furnace inner opening of the ball valve valve seat so as to cover the opening, and the cover has a small diameter through which the optical axis of the objective lens system passes. It is more preferable that the second viewing hole is provided, and the purge gas can be circulated from the back surface of the second viewing hole to the inside of the furnace.
With such a configuration, it becomes possible to more completely prevent contamination of the objective lens system by the atmospheric gas in the furnace containing a large amount of dust and mist.

  According to the present invention, it is possible to measure the three-dimensional charge profile of the blast furnace from the information of the temperature pattern on the upper surface of the charge layer by a pair of infrared cameras. This makes it possible to provide a charge profile meter that is not easily affected by high-concentration dust in the blast furnace, is small and inexpensive, and is easy to measure. According to the method of the present invention, since the measurement time is short and the labor is not required, information on the profile of the entire charge can be obtained almost continuously.

  Further, according to the present invention, when the purge gas is used to prevent lens contamination of the infrared camera, it is possible to completely prevent lens contamination without increasing the purge gas amount, and to easily and reliably protect the lens in an emergency. It has become possible to provide a means that can be used.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings of the examples. FIG. 1 is a schematic diagram showing the mounting position of the infrared camera according to the present invention. In this example, a pair of infrared cameras 2 a and 2 b are attached to an inclined portion at the upper part of the shaft of the blast furnace 1. An in-furnace gas exhaust pipe 3 is disposed on the inclined portion of the furnace shoulder, so that the position of the exhaust pipe 3 is removed and the tip of the charge chute 4 is not disturbed by the view. Install the camera at the same level or below. The two cameras 2a and 2b are preferably arranged at positions symmetrical with respect to the central axis of the blast furnace, but it is not always necessary to stick to this, and it is only necessary that they are arranged as far as possible.
For the infrared cameras 2a and 2b, it is preferable to use a lens having a wide angle (for example, a viewing angle of about 80 degrees) so that the entire surface of the charge 5 in the furnace can be observed.

FIG. 2 is a cross-sectional view showing the configuration of the optical system of the infrared camera in one embodiment of the present invention. This optical system includes a wide-angle objective lens 6, an in-furnace gas blocking filter 7, an image enlargement imaging lens 8, a two-dimensional image light receiving element 9, and an orifice for protecting the objective lens 6 (first orifice 10 and second orifice 10). Orifice 11) and the like. A wide-angle objective lens 6 forms an infrared real image 12 on the surface of the charge 5, and the image is magnified to a desired size by the image enlargement imaging lens 8. Get an image.
In this embodiment, the objective lens 6, the filter 7 and the image enlargement imaging lens 8 are made of germanium having good infrared light transmission, and the two-dimensional image light receiving element 9 is an uncooled bolometer. Is used. Further, an achromatic lens is used for the objective lens 6 and the image enlargement imaging lens 8 for correcting chromatic aberration.
The wavelength range of infrared rays received by this optical system is about 8.0 to 14.0 μm, and a charge temperature of 30 ° C. or more is detected. Since the surface temperature of the blast furnace charge is usually 50 to 600 ° C., the temperature pattern of the charge surface can be reliably detected with this configuration.

  FIG. 3 is a diagram showing the overall configuration of the charged substance profile measuring apparatus in the present embodiment. The pair of temperature pattern detectors (first and second detectors) each include an infrared camera 13 with a built-in light receiving element, a pan head 14 and a lens 15, which are housed in a dustproof case 16. . On the front surface of the lens 15, there is provided a shut-off valve (which uses a ball valve in this embodiment as will be described later) 18 that is differentially operated by an air cylinder 17, and a dust-proof hood 19 in front thereof. The shut-off valve 18 is supplied with lens purge nitrogen 20, and the dust hood 19 is supplied with ball valve seal nitrogen 21 and cooling water 22.

  The image from the infrared camera 13 is input to the image board of a personal computer (PC). The charge profile is determined by image processing. If necessary, a thermal image in the furnace can be displayed on a monitor via an image distributor to monitor the charge properties and gas flow in the vicinity of the charging surface. On the other hand, from the PC, a signal for controlling a control signal of the camera (for example, an image enlargement ratio, a pan head position, an on / off state of a shut-off valve, etc.) is sent to the camera side through a camera control cable.

  Hereinafter, the method of the present invention for measuring the profile of the top surface of the charge using a pair of temperature pattern detectors will be described. FIG. 4 is an explanatory diagram of the measurement principle. In FIG. 4, 15a is the objective lens of the first camera, 15b is the objective lens of the second camera, and the center point of the lens 15a is O as the optical reference point. Further, 23a is an image of the first detector (first camera), and 23b is an image of the second detector (second camera). In the images of the first and second detectors, an isotherm can be drawn, so the isotherm T on the charge surface at a certain temperature (circular for simplicity) is a common feature in the temperature pattern. This isotherm is analyzed.

When an arbitrary point P on the isotherm T is taken, it is recognized as T ₁ and P ₁ on the image 23a and recognized as T ₂ and P ₂ on the image 23b (the position of P ₂ is specified as follows). )
The vector S extending from the point O in the direction of the point P on the isothermal line T from the center of the lens 15a is recognized as _one point P ₁ on the image 23a. Therefore, from the image of the first detector, the point P Only the information on the azimuth of the camera is obtained, and information on the distance between the OPs is not obtained. On the other hand, when the vector S is observed from the second detector, it is observed as a line segment S ₂ extending from the O ₂ point toward the P ₂ point on the image 23b. Since the positions of the lenses of both cameras are fixed, the position of the point O can be specified on the image 23b (point O ₂ ).

Further, since the orientation of the vector S at the first detector is specified, it is possible to plot in which direction the vector S extends from the point O ₂ on the image 23b (this line segment is projected to OP). Called a line). The projection line is given as a straight line on the image 23b, the intersection of the projection line or its extrapolation as isotherms T ₂ is deemed to be P _2. Since the length of the projection line (S ₂ ) on the image 23b also changes depending on the length of the vector S, the distance between OPs can be calculated based on the length of the line segment O ₂ P ₂ .

On the image 23a of the first detector, the azimuth of the point P (the azimuth angle (θ, φ) in spherical coordinates with the point O as the center) is determined. Target position can be calculated.
Since the three-dimensional position of an arbitrary point P on the isotherm T can be calculated, the three-dimensional position of the entire isotherm T on the charge surface can be calculated. If such position information is obtained for a plurality of isotherms (T ₁ , T ₂ , T ₃ ...), It is possible to draw a profile of the top surface of the charge in the entire furnace based on this information. Easy.

Next, a procedure for calculating the three-dimensional position of the point P based on the above principle will be described.
< Determination of coordinate axes>
FIG. 5 is an explanatory diagram of a coordinate axis determination method. FIG. 6 is a diagram showing the relationship between the point Q on the charging surface and the images P and P ′, in order to calculate the three-dimensional profile of the charging surface from the two-dimensional thermal image projected by the camera as follows. Define the coordinate system. In FIG. 5, the optical center of the first camera (the optical main plane center of the objective lens) is defined as the orthogonal axis origin (hereinafter referred to as the origin), and x1, x2 and the vertical axis are defined as x3 on the horizontal plane. In this coordinate system, a point on the charging surface and a point on the camera image are represented. The same coordinate system is used for the second camera, and in the following description, the symbol used in the second camera is attached with “′” to associate with the first camera.

  An arbitrary point Q (u1, u2, u3) on the charging surface is indicated by a point P (x1, x2, x3) on the image plane such as a CCD element built in the first camera as shown in FIG. The image is formed as an inverted real image, reversed and enlarged by an electric circuit, and displayed on the monitor. Since the image filed in the personal computer is used for the calculation of the loading surface profile, the imaging planes π and π ′ are files of the personal computer, and the coordinate axes are given to this file data. Video on a personal computer is handled with polar coordinates P (r, ξ) with the center determined in some way as the origin. The coordinates given to the charging surface image on the personal computer can be set freely, but in this document, the video coordinates are determined so that the actual size of the image displayed on the personal computer monitor becomes the image size of the image plane.

<How to find camera parameters and image plane coordinates>
The point P on the camera image is represented by two-dimensional coordinates P (r, ξ), but in order to associate with the point Q (u1, u2, u3) on the charging surface, the point P is orthogonal coordinates P (x1, x2, x3) must be expressed. The two coordinate systems are converted into each other by a normal vector N 1 which extends from the origin O to the imaging plane π. The calculation requires the length N of the normal vector N shown in FIG. 7 and the angle θ formed with the vertical axis x3. Hereinafter, these two quantities are referred to as camera parameters. N and θ are defined as follows.

FIG. 7 is an explanatory diagram of the definition of camera parameters. In FIG. 7, O is the origin, A (a1, a2, a3) is the point where π and the x3 axis intersect, and N is the point where the normal vector intersects with π. Next, the unit vector in the normal direction is n (l1, l2, l3), and P (x1, x2, x3) is an arbitrary image point on π. Since A and P are on a plane perpendicular to the normal vector N, the length N of N is given by the following standard form of Hesse.
N = | N | = l1 ・ a1 + l2 ・ a2 + l3 ・ a3 (= l1 ・ x1 + l2 ・ x2 + l3 ・ x3) (1)
If the vector OA = A, the angle θ is obtained from the following equation.
θ = cos ^-1 (x) (2)
However, x = (A ・ n) / (| A | ・ | n |) = (a1 ・ n1 ＋ a2 ・ n2 ＋ a3 ・ n3) / (a1 ² + a2 ² + a3 ² ) ^1/2・ (n1 ² + n2 ² +3 ² ) ^1/2
In equations (1) and (2), camera parameters can be obtained by giving A and N.

Next, a relational expression for converting P (x1, x2, x3) to P (r, ξ) is shown. The vector NP giving P (r, ξ) on the π plane is between the known normal vector ON that defines the imaging plane π, the vector OA, and the vector OP expressed in the (x1, x2, x3) coordinate system Given from the relationship that holds.
Vector NP = Vector ON-Vector OP
Vector NA = Vector OA-Vector OP
Therefore, the length r of the vector NP and the angle ξ formed by the vector NP and the vector NA are as follows.
r = {(x1-n1) ² + (x2-n2) ² + (x3-n3) ² } ^1/2 (3)
ξ = cos ^-1 (y1 / y2) (4)
However, y1 = (a1-n1) (x1-n1) + (a2-n2) (x2-n2) + (a3-n3) (x3-n3)
y2 = {(a1-n1) ² + (a2-n2) ² + (a3-n3) ² } ^1/2・ {(x1-n1) ² + (x2-n2) ² + (x3-n3) ² } ^1/2
The above is an expression for obtaining coordinates on the image plane for the point Q of the object.

If the camera is installed so that the imaging plane π is orthogonal to the x1 and x2 planes, P (x1, x2, x3) is converted to P (r, ξ) using the camera parameters.
x1 = -r sin (ξ), x2 = -N sin (θ) + r cos (ξ) cos (θ), x3 = N cos (θ) + r cos (ξ) sin (θ) (5)
P (x1, x2, x3) is converted to P (r, ξ) by the following formula.
ξ = tan ^-1 ((x2 + N × sin (θ)) / x1cos (θ)), r =-x1 / sin (ξ) (6)
For N and θ used in equations (1) and (2), the camera is installed in the blast furnace, the positions of multiple points Q (u1, u2, u3) on the charging surface are obtained, and the corresponding point coordinates P on the camera image are obtained. Obtained from (r, ξ).

<Camera calibration>
The calibration for obtaining camera parameters N and θ is as follows. Regarding the symbols used in this description, the point on the charging surface is Q, and the point on the imaging surface is P.
FIG. 8 is an explanatory diagram of a camera parameter determination method. In FIG. 8, the interval | OV | between the camera origin and the charging surface is measured and is defined as H (| OV | is the length of the straight line OV). If the origin (image center point) on the image plane π is O, the corresponding O point on the charging surface is determined. The straight line PO-QO becomes the image center point on the optical axis of the camera, and determines the image coordinates. The position coordinates of the camera are on the vertical axis x3.

With such an arrangement, the QO and QV on the loading surface are determined, the corresponding point coordinates PO and PV on the video screen are read, and the camera parameters are obtained from the following calculations.
θ = tan ^-1 (| QV-QO | / H) = tan ^-1 (| O-PO | / | PV-PO |), N = (| PV-PO | / | QV-QO |) × H… ……(Four)
In the actual calibration, a point on the charging surface further includes a plurality of points to improve accuracy such as correcting distortion of the camera lens.

<Relationship between two coordinates>
The origin of the two cameras is on the same straight line (x2, x2 'axis). When the distance | O-O '| between the origins O-O' is D, the conversion from the first camera coordinates (first coordinates) to the second camera coordinates (second coordinates) is as follows.
x1 '= x1, x2' = d -x2, x3 '= x3 (3)
By combining equations (1), (2), and (3), the two camera image coordinates can be related to each other via a point on the loading surface.

Next, the procedure for calculating the charge profile will be described. This procedure consists of the following steps:
(1) Import two-dimensional temperature profiles measured by two cameras into a personal computer and create characteristic curves T and T 'such as isothermal lines.
(2) Select an arbitrary point P (r, ξ) on the T curve and convert it to P (x1, x2, x3) using equation (1).
(3) Since the coordinate of the corresponding point Q on the charging surface of P is a road, the coordinate of Q * is determined from the following equation assuming the length U (= | OQ |) from the origin O. “*” Is a symbol indicating a virtual straight line. The coordinates Q * (u1 *, u2 *, u3 *) of Q * are given by the following equation.
u1 * =-(U / N) x1, u2 * =-(U / N) x2, u3 * =-(U / N) x3, U = (u1 * ² + u1 * ² + u1 * ² ) ^{1 / 2} (5)
Q * (u1 * ', u2 *', u3 * ') is
u1 * '= u1 *, u2 *' = D-u2 *, u3 * '= u3 * (6)

(4) The corresponding point P ′ (x1 ′, x2 ′, x3 ′) on the imaging plane π ′ plane of the second camera is given by the following equation.
x1 '=-(N / U) u1 *', x2 '=-(N / U) u2 *', x3 '=-(N / U) u3 *'
U = (u1 * ² + u1 * ² + u1 * ² ) ^1/2 (7)
(5) P ′ (x1 ′, x2 ′, x3 ′) is converted to P ′ (r ′, ξ ′) using equation (2). As a result, the point Q * on the virtual straight line is represented as video coordinates on P (r, ξ) on the π plane and P ′ (r ′, ξ ′) on the π ′ plane. Note that the Q * point does not exist on the charging surface unless U gives the correct length, and therefore the P ′ point is not on the curve T ′ on the π ′ plane.

(6) Next, U of u1 *, u2 * and u3 * is changed so as to satisfy the expression (5). As a result, the Q * point moves on the POQ line. Correspondingly, the locus of point P ′ draws a straight line on the π ′ plane.
(7) U when the straight line drawn by the point P ′ on the π ′ plane intersects the curve T ′ gives the coordinates of the point Q on the charging surface.
(8) The point P on T is changed to determine the coordinates of T on the charging surface.
(9) Change the isotherm temperature level to create various Ts for the first and second cameras, create Ts that cover the entire surface of the charging surface, determine their coordinates on the charging surface, and load Determine the 3D coordinates of the entire surface.

  9A and 9B are diagrams showing the structure of the camera mounting portion in the present embodiment. FIG. 9A is a longitudinal sectional view, and FIG. 9B is a transverse sectional view. A through hole is provided in communication with the iron core of the blast furnace shoulder of the camera mounting part and the refractory material below (not shown), and a ball valve is provided as a shut-off valve directly above the through hole. The inside of the furnace is observed through the through-hole portion of the ball valve.

  As shown in FIG. 9, a partition wall (first orifice 10) having a small-diameter viewing hole is provided at the center of the ball valve rotating ball 24 in the vicinity of the inner end portion of the ball valve. The objective lens 6 is arranged in the part. As a matter of course, the optical axis of the objective lens 6 is set so as to pass through substantially the center of the hole of the first orifice 10. Further, by using the ball valve in this way, the objective lens 6 can be disposed close to the orifice 10. Thus, using the wide-angle lens as the objective lens 6 so that the entire surface inside the blast furnace having a large diameter can be observed is an effect of arranging the objective lens in the ball valve.

The ball 24 is rotationally driven by the air cylinder 17 via the ball rotation shaft 25. When necessary, the ball 24 is rotated so that the optical system of the infrared camera can be shielded from the furnace atmosphere. Further, the ball rotating shaft 25 is sealed by the shaft packing 26 so that the high-pressure gas in the blast furnace does not leak. Two in-furnace gas barrier glasses 27 are disposed on the upper side of the ball 24, and an infrared camera 13 incorporating a magnification imaging lens 8 and a light receiving sensor (not shown) is disposed on the upper side thereof.
In addition, a cover 29 is provided so as to cover an opening (inside the furnace) of the valve seat 28 of the ball valve, and the cover 29 is also provided with a partition wall (second orifice 11) provided with a small-diameter viewing hole. Yes. Both the first orifice 10 and the second orifice 11 are intended to prevent purge dust (nitrogen gas in this embodiment) from flowing from the back to prevent dust, oil smoke, and the like in the furnace from entering the optical system. Is.

  FIG. 10 is an explanatory diagram of the flow direction of the purge gas in the present embodiment. A lens purge nitrogen 20 is supplied to the ball valve and flows out through the hole of the first orifice 10. This flow is in the longitudinal direction (axial direction). On the other hand, the ball valve seal nitrogen 21 is supplied to the lower cover 29 of the ball valve. FIG. 10B is a cross-sectional view taken along the line AA in FIG. As seen in FIG. 10B, the ball valve seal nitrogen 21 is blown in the tangential direction and flows out through the hole of the second orifice 11 as a swirling flow. Thus, the dust-proof effect can be further enhanced by blowing the purge gas in two stages and combining the axial flow and the swirl flow.

Two infrared cameras having a wide field of view were installed at the blast furnace furnace mouth as shown in FIG. 11, and the charge profile was measured by the method of the present invention. The two cameras were installed in the x2, x3 plane (ie, x2 ', x3' plane) and made the same height.
<Example of charging surface height calculation>
First, camera parameters were calibrated with respect to two cameras arranged as shown in FIG. 11 during a quiescent period when the operation of the blast furnace was stopped. Since the charging surface during rest is almost flat, the boundary image between the charging surface and the blast furnace inner wall is close to a perfect circle.

A point heat source such as a floodlight is placed on the SN line on the loading surface, and the first camera image is recorded on a personal computer. The point O that determines the optical axis of the camera changes the point light source position while looking at the personal computer screen, and the position where the point O comes to the center of the screen is set as the optical axis point O. For point V on the vertical axis, place a point heat source directly below the camera lens and record the image as point V. The same measurement was performed for the second camera, and O 'and V' points were determined. The camera interval is | V−V ′ | = d. In addition, the loading surface height measured from the camera is H.
As a result of measuring the camera installation position by the above method, the values shown in Table 1 were obtained. The values shown in Table 2 were obtained on the video screen on the personal computer for each point on the charging surface shown in Table 1. Further, Table 3 is obtained by calculating the camera parameters by the above-mentioned equation (4).

Next, we calculated the charging surface height for the P1 and P2 points arbitrarily selected on the boundary line image, and verified the validity of this method by comparing with the measured values. FIG. 12 is an image of a circular profile created by the intersection line between the inner wall of the blast furnace and the charging surface during the resting wind captured by two cameras. The boundary image is the same for camera 1 and camera 2, but PS, PE, PN, and PW are reversed, and PE and PW are significantly above the horizontal axis.
In order to obtain the charging surface height, P1 and P2 are appropriately determined on the boundary line. Table 4 shows their coordinates.

  When the length of the virtual straight line created on the POQ is changed, the virtual straight line image is displayed on the second camera image. The right figure of FIG. 12 is the second camera image, and the straight tip locus is indicated by a dotted line. The height H when the straight line intersects the boundary line gives the correct height. The measurement results are summarized in Table 5. Indicates the coordinates and height H when the virtual straight line intersects the boundary line. The calculated value corresponds well with the actual measurement value. As can be seen from this example, if the boundary line is measured with two cameras, the position of the charging surface can be measured almost accurately, and the accuracy is almost the same as the triangulation method conventionally used for ranging. It is considered equivalent.

<Measurement example of charge profile>
The following is an example of a 3D charging surface profile obtained by measuring charging surface images with two infrared cameras. The infrared image of the charging surface is taken into a personal computer and converted into a temperature image. In the case of a blast furnace, the shape of the charging surface is closely related to the temperature distribution, and in the case of a temperature image, a temperature distribution that is almost symmetrical about the central axis is often obtained. When creating an isotherm profile, the temperature is chosen so that the isotherm covers the entire charging surface. An isotherm distribution map as shown in FIG. 13 is obtained by smoothing the somewhat uneven isotherm. The temperature profiles captured by the two cameras are almost the same, which indicates that the temperature distribution is an axis target.

In the figure, the positions of 0 ° (south point), 90 ° (east point), 180 ° (north point), and 270 ° (west point) with respect to the center of the blast furnace for each isothermal line are selected as evaluation points. , PS, PE, PN, and PW, and the height at each position was determined. Since the isothermal line shape is simple, the evaluation points are 4 points for one isotherm. However, if the isothermal line shape is complicated, the evaluation points need to be increased.
The measurement results are shown in Table 5. The charging surface height was measured with an existing microwave profilometer, and the accuracy was verified. Table 6 shows a comparison between the calculation result of the method of the present invention and the measurement result of the microwave profilometer.

When Table 6 is graphed, FIG. 14 is obtained. If the measurement data is repeatedly measured and smoothed, the accuracy is further improved. Moreover, in the data measured by this method, the north-south profile and the east-west profile are in good agreement, and it can be seen that the charging surface profile is axisymmetric.
This profilometer can measure not only the three-dimensional shape of the profile in real time, but also the time change, which was not possible with the conventional profilometer.

< Measurement method of charging surface profile with one camera >
As can be seen from FIG. 14, when the charging surface profile is symmetric with respect to the blast furnace central axis, the images of the first camera and the second camera coincide. In this case, the second camera is not necessary, and the second camera image can be synthesized from the first camera image in the personal computer. The blast furnace is designed to be symmetrical with respect to the central axis, and the operation is performed so that the charging surface takes a symmetrical pattern with respect to the central axis. Therefore, in most cases, the isotherm distribution often has a clean axisymmetric pattern. When two cameras cannot be installed due to restrictions on equipment, it is possible to measure the charging surface pattern with a single device assuming that the charging surface is a central axis symmetrical pattern.
In addition, the method for calculating the profile also uses P (r, ξ) on the first camera image plane π plane and P ′ (r ′, ξ) on the second camera image plane π ′ plane with the profile height as a parameter in advance. If the relationship of ') is tabulated, camera image distortion can be corrected and the profile can be determined by simple interpolation calculation.

It is a figure which shows the example of the attachment position of the infrared camera in this invention. It is a figure which shows the structure of the optical system of the infrared camera in the Example of this invention. It is a figure which shows the whole structure of the blast furnace charge profile measuring apparatus which is an Example of this invention. It is explanatory drawing of the measurement principle of this invention. It is explanatory drawing of the determination method of the coordinate axis in calculation of the blast furnace charge profile of this invention. It is explanatory drawing of the relationship between the point Q on the charging surface and image | video P, P 'in calculation of the blast furnace charging profile of this invention. It is explanatory drawing of the definition of the camera parameter in calculation of the blast furnace charge profile of this invention. It is explanatory drawing of the determination method of the camera parameter in calculation of the blast furnace charge profile of this invention. It is a figure which shows the structure of the infrared camera attachment part in a present Example. It is explanatory drawing of the outflow situation of the purge gas for lens protection in a present Example. It is explanatory drawing of the measurement point used for the camera arrangement | positioning and camera parameter determination in a present Example. It is a figure which shows the position of the camera image and evaluation point of the circular profile made with a blast furnace inner wall and a charging surface in a present Example. It is an isotherm distribution map created from two camera images in the present embodiment. It is a figure which shows the comparison of the calculation result of the charge profile in a present Example, and the measurement result of a microwave profilometer.

Explanation of symbols

1: Blast furnace 2a, 2b: Infrared camera 3: Furnace gas exhaust pipe 4: Charge chute 5: Furnace interior charge 6: Wide-angle objective lens 7: Furnace gas blocking filter 8: Image magnification imaging lens 9 : Two-dimensional image light receiving element 10; First orifice 11; Second orifice 12: Infrared image on charged surface 13: Infrared camera 14: Camera platform 15, 15a, 15b: Lens 16: Dust-proof case 17: Air cylinder 18: Shut-off valve 19: Dust-proof hood 20: Lens purge nitrogen 21: Ball valve seal nitrogen 22: Cooling water 23a, 23b: Detector image 24: Ball valve rotating ball 25: Ball rotating shaft 26: Shaft packing 27: Furnace gas Barrier glass 28: Ball valve seat 29: Cover

Claims (5)

A pair of infrared cameras provided with a two-dimensional light-receiving sensor that is arranged on the furnace shoulder of the blast furnace and receives infrared light from almost the entire top surface of the furnace interior, and detects the intensity of the infrared light. A temperature pattern detector that creates a three-dimensional temperature pattern is placed in a pair of blast furnaces, and information on the temperature pattern of the upper surface of the furnace interior is observed from different directions at the same time,
In the two-dimensional temperature pattern of both detectors, a characteristic curve having a common characteristic is defined, an arbitrary point P on the characteristic curve is selected, and the point P is compared with the position of the point P in the images of the two detectors. Calculate the three-dimensional position of P,
A method for measuring a blast furnace charge profile, wherein a shape of an upper surface of a charge layer in a furnace is drawn from position information of a plurality of characteristic curves.   The characteristic portion C1 of the isotherm image is determined from the two-dimensional temperature pattern of one of the detectors (hereinafter referred to as the first detector), an arbitrary point P on the isotherm image C1 is selected, and the optical of the first detector is selected. An imaginary straight line L extending from the reference point O in the direction of the point P is assumed, and an image of the characteristic portion C2 corresponding to C1 obtained by the other detector (hereinafter referred to as a second detector) is displayed on the imaginary straight line L. And the length of the virtual straight line L is changed, and the virtual line L when the L intersects the characteristic partial image C2 on the second detector is used to change the first detector and the charging surface. 2. The method of measuring a blast furnace charge profile according to claim 1, wherein the positional relationship of the corresponding points P is given. A pair of infrared cameras provided with a two-dimensional light-receiving sensor that is arranged on the furnace shoulder of the blast furnace and receives infrared light from almost the entire top surface of the furnace interior, and detects the intensity of the infrared light. A feature portion C1 of an isotherm image is determined from a pair of temperature pattern detectors for creating a next temperature pattern and a two-dimensional temperature pattern of the first detector, an arbitrary point P on the isotherm image C1 is selected, A straight line L extending from the optical reference point O of the detector in the direction of the point P is assumed, and an image of the characteristic portion C2 corresponding to C1 obtained by the other detector (hereinafter referred to as a second detector) is obtained. The virtual straight line L is overlapped, the length of the virtual straight line L is changed, and the virtual straight line L when the L intersects with the characteristic partial image C2 on the second detector is changed onto the charging surface. A position calculating means for determining the position of the corresponding point P;
An apparatus for measuring a blast furnace charge profile, comprising: plotting means for drawing a shape of an upper surface of a charge layer in a furnace from position information of a plurality of the characteristic portions. At the mounting position of the infrared camera, a through-hole communicating with the blast furnace iron skin and its lower refractory is provided, and a ball valve is disposed outside the through-hole of the iron skin in close proximity thereto,
A partition wall having a small-diameter viewing hole is provided in the center of the ball valve near the inner end of the through hole in the ball,
And the objective lens system of the camera is disposed in the inside of the ball penetration part in the vicinity of the rear surface of the partition wall so that the optical axis thereof passes through the center of the viewing hole, and infrared light from the objective lens system is transmitted. And is configured to enter the two-dimensional light receiving sensor via an optical system as necessary,
4. The apparatus for measuring a blast furnace charge profile according to claim 3, wherein purge gas can be circulated from the back surface to the inside of the furnace through the peep hole.   A cover is provided outside the inner opening of the ball valve valve seat so as to cover the opening, and a second small-diameter viewing hole through which the optical axis of the objective lens system passes is provided at the center of the cover. The apparatus for measuring a blast furnace charge profile according to claim 4, wherein purge gas can be circulated to the inside of the furnace from the back side of the second peephole.

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