JP3661900B2 - Particle size detection apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a particle size detection apparatus and method for measuring particle size segregation on the top surface of a blast furnace.
[0002]
[Prior art]
In a blast furnace for melting iron ore, coke and iron ore are normally charged alternately from the upper part of the furnace, and thereafter, the profile of the furnace top surface is set to have a V-shaped cross section by a stirrer. The desired V-shape of the furnace top profile has a very important meaning in terms of saving the fuel consumption of the blast furnace, and thus means for accurately measuring the furnace top profile is required.
[0003]
In order to satisfy this requirement, Japanese Patent Publication No. 56-9644, Japanese Patent Laid-Open No. 54-65059, etc. have been proposed and applied.
The “surface shape detection method” disclosed in Japanese Examined Patent Publication No. 56-9644 uses a laser beam 1 as a beam for light cutting, as schematically shown in FIG. 4, and deflects the laser beam with a scanning mirror 2 to be measured. The object to be measured 3 is projected onto the surface 3 of the object, and the heated part P of the object to be measured is imaged by the long-wave radiation emitted from the surface part P heated by the projection. The surface shape is detected.
[0004]
Further, as schematically shown in FIG. 5, the “profile measuring device” disclosed in Japanese Patent Application Laid-Open No. 54-65059 scans the surface to be measured 3 with a laser beam 5 using a pulsed laser that oscillates repeatedly as a light source, The scattered light 6 from the surface 3 is collected by a light receiving optical system 7 having a predetermined aperture diameter, and the profile of the measured surface 3 is obtained from the locus of an image drawn on the focal plane of the light receiving optical system 7. .
[0005]
[Problems to be solved by the invention]
On the other hand, the basic physical phenomenon that occurs with the raw material charging at the top of the blast furnace is as follows: (1) Movement as an aggregate of charged particles and (2) Particle size segregation caused by particle size composition. Become. The movement of (1) as an assembly can be grasped indirectly by measuring the furnace top profile as described above, but the particle size segregation of (2) has no conventional measuring means, so the blast furnace is operated by relying on experience and feeling. There was an inevitable problem.
[0006]
In other words, the particle size of the particles (ore and coke) stacked inside when operating at high temperatures and there are many light scattering media inside, such as the top surface of a blast furnace, where the inside cannot be viewed with a normal camera, etc. There is no appropriate means for measuring (particle size), and there has been a strong demand for the development of such means.
[0007]
The present invention has been developed to meet such a demand. That is, the object of the present invention is to detect particle size segregation in an environment where there is a large number of light scattering media inside and operated at a high temperature, such as the top surface of a blast furnace, and particle size detection that can be fed back to the operation. It is to provide an apparatus and method.
[0008]
[Means for Solving the Problems]
According to the present invention, there is provided a beam projecting device that projects a laser beam onto a surface to be measured, and a beam receiving device that receives scattered light of the laser beam from a projecting position on the surface to be measured. The light projecting point of the optical device and the light receiving point of the beam receiving device are separated from each other by a certain reference length L, and further includes a measured surface arithmetic device, and the projected surface angle α with respect to the reference length L is measured by the measured surface arithmetic device. And the light receiving angle β, the vertical height H from the reference length L of the surface to be measured and the horizontal distance C from the light projection position are calculated, and the surface to be measured is scanned by changing the light projection angle α. There is provided a particle size detection apparatus characterized by detecting a blind spot pitch Δα at which the intensity of scattered light decreases and calculating a particle diameter D of the particle from the blind spot pitch Δα. According to a preferred embodiment of the present invention, the particle size D is calculated by the equation (H ² + C ² ) ^0.5 × Δα by the measured surface arithmetic device.
[0009]
Further, according to the present invention, the laser beam is projected / received from the light projecting point and the light receiving point separated by a certain reference length L, and the surface to be measured is determined from the light projecting angle α and the light receiving angle β with respect to the reference length L. The vertical height H from the reference length L and the horizontal distance C from the light projection position are calculated, and the blind angle Δα at which the surface to be measured is scanned by changing the light projection angle α to reduce the intensity of the scattered light. Is detected, and the particle size D of the particle is calculated from the blind spot pitch Δα.
[0010]
According to the apparatus and method of the present invention described above, a beam projecting device, a beam receiving device, and a measured surface computing device are provided, and a laser beam is projected from the projecting point and the receiving point separated by a certain reference length L. / By receiving light, the vertical height H from the reference length L of the surface to be measured and the horizontal distance from the light projection position from the projection angle α and the light reception angle β with respect to the reference length L by triangulation technology (laser scanning etc.) C can be calculated. In this case, by combining ultra-high sensitivity light detection technology (equivalent to photon counting), it is possible to accurately detect a weak light signal even in a place where there are many light scattering media.
[0011]
Further, this technique is applied to detect a blind spot pitch Δα at which the intensity of scattered light decreases when scanning the surface to be measured by changing the projection angle α, and from this blind spot pitch Δα, the particle diameter D of the particle is obtained. The position (vertical height H and horizontal distance C) can be calculated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and used for the common part in each figure.
FIG. 1 is an overall configuration diagram of a particle size detection apparatus according to the present invention. In this figure, a particle size detection apparatus 10 according to the present invention includes a beam projecting device 12 (projecting unit) that projects a laser beam 5 (laser light) onto a surface to be measured 3, and a projection position on the surface to be measured 3. A light receiving device 14 (light receiving unit) for receiving the scattered light 6 of the laser beam 5. The surface to be measured 3 is a laminated surface of coke and iron ore charged in the blast furnace in this figure, but the present invention is not limited to this and can be applied to other surfaces to be measured.
[0013]
In FIG. 1, a beam projector 12 (projector) includes a laser controller 12a, a laser power source 12b, a laser oscillator 12c, and a mirror scanner 13. The mirror scanner 13 is a reflection mirror that can rotate around the axis of the laser beam emitted from the laser oscillator, reflects the laser beam 5 emitted from the laser oscillator 12c toward the surface to be measured 3, and The surface to be measured 3 is scanned by swinging.
[0014]
The beam receiving device 14 (light receiving unit) includes a mirror scanner 14a, a lens 14b, a rotary optical attenuator 14c, a fiber array 14d, and a light receiving control panel 15. The mirror scanner 14a is a reflecting mirror that can swing around an axis parallel to the reflecting surface. The mirror is swung according to the position of the surface to be measured 3 projected by the beam projecting device 12, and the scattered light 6 of the laser beam 5 from the light projecting position of the surface to be measured 3 is always stably received. Reflected toward 14d. The lens 14b is positioned between the mirror scanner 14a and the light receiver array 14d, and collects the scattered light 6 on the detection surface of the light receiver array 14d.
[0015]
Furthermore, the particle size detection apparatus 10 of the present invention includes a measured surface arithmetic device 16 (system control unit). The measured surface arithmetic device 16 (system control unit) includes a system control panel 16a and a display 16b.
[0016]
FIG. 2 is a diagram showing the measurement principle of the furnace top profile by the apparatus of FIG. As shown in this figure, the light projecting point A of the beam projecting device 12 and the light receiving point B of the beam receiving device 14 are installed with a certain reference length L therebetween. Further, the above-described measured surface calculation device 16 makes the vertical height H from the reference length L of the measured surface 3 and the horizontal distance C from the light projection position B from the light projection angle α and the light reception angle β with respect to the reference length L. And to calculate.
[0017]
FIG. 3 is a diagram showing the measurement principle of particle size detection by the apparatus of FIG. As shown in this figure, when the measurement surface 3 is scanned by changing (increasing or decreasing) the projection angle α of the laser beam 5 from the projection point A, depending on the position of the measurement surface 3 to be projected. There is a blind spot where the scattered light on the measurement surface 3 cannot be observed from the light receiving point B. That is, when the laser beam 5 is projected on the back side of the particle as viewed from the light receiving point B, the scattered light is hardly observed, and the scattered light can be observed only when scanning the front side. A pitch angle Δα (hereinafter referred to as a blind angle pitch) with respect to the projection angle α of the blind angle at which the intensity of the scattered light decreases increases and decreases in proportion to the particle diameter D. The blind spot pitch Δα is a difference between the nth blind spot start angle αn and the (n + 1) th blind spot start angle αn + 1 (that is, Δα = αn + 1−αn). Therefore, the blind spot pitch Δα can be detected, and the particle diameter D and the position of the particle can be calculated from the blind spot pitch Δα by the measured surface calculation device 16.
[0018]
When the particles are substantially spherical and the blind spot pitch Δα substantially corresponds to the diameter, geometrically, the particle size D is expressed by Equation 1 of (H ² + C ² ) ^0.5 × Δα by the measured surface calculation device 16. An approximate value can be calculated. In this equation, C is a horizontal distance from the light projection position B, and can be replaced with L / 2-R (R is a radial position). Further, although H and C (or R) in Equation 1 change during scanning of the blind spot pitch Δα, an average value or the like can be used as a representative value (global value) for rough estimation. Furthermore, actual ore and coke have an uneven surface, and when the thin laser beam 5 is used, the blind spot pitch Δα may not correspond to the diameter. In such a case, it is necessary to appropriately adjust the projection diameter of the laser beam 5 so that a blind spot pitch Δα representing the particle diameter D can be obtained. For example, when the unevenness of the surface is very severe, it is possible to grasp the dispersion state of the ore and coke by using a projection diameter d that is about half the known diameter of the ore or coke to be used.
[0019]
The apparatus described above is used as follows.
(A) First, the laser beam 5 is projected / received from the light projecting point A and the light receiving point B separated by a certain reference length L, and the surface to be measured 3 is determined from the light projecting angle α and the light receiving angle β with respect to the reference length L. The vertical height H from the reference length L and the horizontal distance C from the projection position A are calculated.
(B) Further, by changing the projection angle α, the surface to be measured 3 is scanned to detect the dead angle pitch Δα at which the intensity of the scattered light decreases, and the particle diameter D of the particle is calculated from the dead angle pitch Δα.
[0020]
(A) and (B) are preferably performed simultaneously by a single scan. However, if necessary, (A) and (B) can be performed as separate steps.
[0021]
In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.
[0022]
【The invention's effect】
According to the apparatus and method of the present invention described above, a beam projecting device, a beam receiving device, and a measured surface computing device are provided, and a laser beam is projected from the projecting point and the receiving point separated by a certain reference length L. / By receiving light, the vertical height H from the reference length L of the surface to be measured and the horizontal distance C from the light projection position are calculated from the projection angle α and the reception angle β with respect to the reference length L by the triangulation technique. be able to. In this case, by combining ultra-high sensitivity light detection technology (equivalent to photon counting), it is possible to accurately detect a weak light signal even in a place where there are many light scattering media.
[0023]
Further, this technique is applied to detect a blind spot pitch Δα at which the intensity of scattered light decreases when scanning the surface to be measured by changing the projection angle α, and from this blind spot pitch Δα, the particle diameter D of the particle is obtained. The position (vertical height H and horizontal distance C) can be calculated.
[0024]
Therefore, the particle size detection apparatus of the present invention can measure particle size segregation in an environment where there are many light scattering media inside such as the top surface of a blast furnace, and feedback to the operation is applied. It has an excellent effect.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a particle size detection apparatus according to the present invention.
FIG. 2 is a diagram showing a measurement principle of a furnace top profile.
FIG. 3 is a diagram illustrating a measurement principle of particle size detection.
FIG. 4 is a configuration diagram of a conventional example for detecting a furnace top profile.
FIG. 5 is a configuration diagram of another conventional example for detecting a furnace top profile.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser beam 2 Scanning mirror 3 Surface to be measured 5 Laser beam 6 Scattered light 7 Light receiving optical system 10 Grain size detector 12 Beam projector (projector)
13 Mirror scanner 14 Beam receiving device (light receiving unit)
14a Mirror scanner 14b Lens 14c Rotating optical attenuator 14d Photoreceiver array 15 Light reception control panel 16 Surface measurement apparatus (system control unit)

Claims (3)

A beam projecting device for projecting a laser beam on the surface to be measured; and a beam receiving device for receiving the scattered light of the laser beam from the projecting position on the surface to be measured, the projecting point of the beam projecting device And the light receiving point of the beam receiving device are separated by a certain reference length L,
Further, a measurement surface calculation device is provided, and from the projection angle α and the light reception angle β with respect to the reference length L, the measurement surface calculation device calculates the vertical height H from the reference length L of the measurement surface and the projection position. The horizontal distance C is calculated, and further, the projection angle α is changed to scan the surface to be measured to detect the dead angle pitch Δα at which the scattered light intensity decreases, and the particle diameter D of the particle is determined from the dead angle pitch Δα. A particle size detection apparatus characterized by calculating. The particle size detection apparatus according to claim 1, wherein the particle size D is calculated by the equation of (H ² + C ² ) ^0.5 × Δα by the measured surface calculation device. A laser beam is projected / received from a light projecting point and a light receiving point separated by a certain reference length L, and a vertical height from the reference length L of the surface to be measured from the light projecting angle α and the light receiving angle β with respect to the reference length L. H and the horizontal distance C from the light projection position are calculated, and further, the light projection angle α is changed to scan the surface to be measured to detect a blind spot pitch Δα at which the intensity of scattered light decreases, and the blind spot pitch Δα The particle size detection method characterized by calculating the particle diameter D of particle | grains from this.

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