JPH10176908A - Apparatus and method for detecting grain size - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure grain size segregation under such circumstances with a high temperature and much light scattering medium by projecting a laser beam to a face to be measured, scanning the face with a light projection angle varied for detecting a dead angle pitch where strength of scattering light drops and calculating a grain diameter of grains by a specific equation from the dead angle pitch. SOLUTION: A projection point A and a reception point B of a laser beam are at a certain reference length L, wherein a vertical height H from the reference length L on a face 3 to be measured and a horizontal distance C from the projection point A are calculated from a light projection angle α and a light reception angle βwith respect to the reference length L. Further the face 3 is scanned while varying the light projection angle α for detecting a dead angle pitch Δα where strength of scattering light drops, and from the dead angle pitch Δα a, a grain diameter D of grains is calculated by an equation of D=(H<2> +C<2> )<0.5> ×Δα. Therefore in this grain size detector, under circumstances such as a blast furnace top face with a high temperature and including much light scattering medium inside, grain size segregation can be measured and feedback to operation is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for measuring particle size segregation at the top of a blast furnace.

[0002]

2. Description of the Related Art In a blast furnace for dissolving iron ore, coke and iron ore are usually charged alternately from the upper part of the furnace, and then 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 top profile is very important in saving fuel consumption of the blast furnace, and therefore a means for accurately measuring the top profile is required.

In order to satisfy this demand, Japanese Patent Publication No. 56-9 / 1981
No. 644 and Japanese Patent Application Laid-Open No. 54-65059 have been proposed and filed. Japanese Patent Publication No. 56-9644 discloses a "surface shape detection method", as schematically shown in FIG.
A laser beam 1 is used as a light cutting beam, and the laser beam is deflected by a scanning mirror 2 and projected on a surface 3 of an object to be measured, and a long-wavelength radiation beam emitted from a surface portion P heated by the projection. Captures an image of the heated portion P of the measured object, and detects the surface shape of the measured object from the trajectory of the heated portion.

A profile measuring apparatus disclosed in Japanese Patent Laid-Open Publication No. Sho 54-65059 scans a surface 3 to be measured with a laser beam 5 using a pulsed laser that repeatedly oscillates as a light source, as schematically shown in FIG. The scattered light 6 from the measured surface 3 is condensed 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. Things.

[0005]

On the other hand, the basic physical phenomena that occur with the charging of raw materials at the blast furnace top are the movement of the charged particles as an aggregate and the particle size caused by the particle size composition. And segregation. The movement of the aggregate can be grasped indirectly by the above-mentioned measurement of the furnace top profile, but the particle size segregation has no conventional measurement means, so that the blast furnace must be operated based on experience and feeling. was there.

That is, when operating at a high temperature and having many light scattering media inside such as the top surface of a blast furnace and the interior cannot be seen by a normal camera or the like, the particles (ore or coke There is no suitable means for measuring the particle size (particle size), and the development of such means has been strongly demanded.

[0007] The present invention has been devised to satisfy such a demand. That is, an object of the present invention is to measure the particle size segregation in an environment operated at a high temperature and having many light scattering media inside, such as the top surface of a blast furnace, and to detect the particle size segregated to give feedback to the operation. It is to provide an apparatus and a method.

[0008]

According to the present invention, there is provided a beam projecting device for projecting a laser beam onto a surface to be measured, and a beam receiving device for receiving scattered light of the laser beam from a projecting position on the surface to be measured. A light projecting point of the beam projecting device and a light receiving point of the beam light receiving device are separated from each other by a fixed reference length L. The device further includes a measured surface calculating device. The vertical height H of the surface to be measured from the reference length L and the horizontal distance C from the light projection position are calculated from the projection angle α and the light reception angle β with respect to the reference length L, and the projection angle α is further changed. Blind spot pitch Δ at which the intensity of the scattered light is reduced by scanning the surface to be measured
α is detected, and the particle diameter D of the particles is calculated from the blind spot pitch Δα. According to a preferred embodiment of the present invention, the particle size D is calculated by the above-mentioned measured surface computing device by the formula of (H ² + C ² ) ^0.5 × Δα.

Further, according to the present invention, a laser beam is projected / received from a light projecting point and a light receiving point separated by a fixed reference length L, and the laser beam is received 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 of the measurement surface and the horizontal distance C from the light projecting position are calculated, and the surface to be measured is scanned by changing the light projection angle α to reduce the intensity of the scattered light. Detecting the blind spot pitch Δα and calculating the particle diameter D of the particles from the blind spot pitch Δα;
A method for detecting particle size is provided.

According to the above-described apparatus and method of the present invention,
It is equipped with a beam projector, a beam receiver, and a device to be measured, and emits / receives a laser beam from a projecting point and a receiving point separated by a fixed reference length L, thereby forming a triangulation technology (laser scanning). Etc.), the vertical height H of the measured surface from the reference length L and the horizontal distance C from the light projection position can be calculated from the projection angle α and the light reception angle β with respect to the reference length L. In this case, by combining an ultra-high sensitivity light detection technology (equivalent to photon counting), a weak light signal can be accurately detected even in a place where there are many light scattering media.

Further, by applying this technique and detecting the blind spot pitch Δα at which the intensity of the scattered light decreases when scanning the surface to be measured by changing the projection angle α, this blind spot pitch Δα is detected.
The particle diameter D of the particle and its position (vertical height H and horizontal distance C) can be calculated from α.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common parts are denoted by the same reference numerals. FIG. 1 is an overall configuration diagram of a particle size detection device according to the present invention. In this figure, a particle size detecting device 10 of the present invention includes a beam projecting device 12 for projecting a laser beam 5 (laser light) onto a surface 3 to be measured.
(Light projecting unit) and a beam receiving device 14 (light receiving unit) that receives the scattered light 6 of the laser beam 5 from the projecting position of the surface 3 to be measured. Although the measured surface 3 is a lamination surface of coke and iron ore charged in the blast furnace in this figure, the present invention is not limited to this, and can be applied to other measured surfaces.

In FIG. 1, a beam projecting device 12 (projecting section) includes a laser controller 12a, a laser power source 12
b, a laser oscillator 12c and a mirror scanner 13. The mirror scanner 13 is a reflection mirror that is rotatable about 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 3 to be measured, and The surface to be measured 3 is scanned by swinging.

The beam receiving device 14 (light receiving unit) includes a mirror scanner 14a, a lens 14b, a rotary optical attenuator 14,
c, a fiber array 14d and a light receiving control panel 15. The mirror scanner 14a is a reflection mirror that can swing about an axis parallel to the reflection surface. The mirror is swung in accordance with the position of the measured surface 3 projected by the beam projecting device 12, and the scattered light 6 of the laser beam 5 from the projected position of the measured surface 3 is constantly stabilized. The light is reflected toward 14d. The lens 14b is located 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.

Further, the grain size detecting device 10 of the present invention includes a measured surface computing device 16 (system control unit). The measured surface calculation device 16 (system control unit) includes a system control panel 16a and a display 16b.

FIG. 2 is a diagram showing the principle of measuring the furnace top profile by the apparatus shown in 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 light receiving device 14 are set at a fixed reference length L. Further, the above-described measured surface computing device 16 calculates the vertical height H of the measured surface 3 from the reference length L and the horizontal distance C from the light projecting position B based on the light projecting angle α and the light receiving angle β with respect to the reference length L. Is calculated.

FIG. 3 is a diagram showing the principle of measurement of particle size detection by the apparatus shown in FIG. As shown in this figure, the projection angle α of the laser beam 5 from the projection point A is changed (increased or decreased).
Then, when the surface 3 to be measured is scanned, the surface 3
Depending on the position, there is a blind spot where the scattered light from the light receiving point B on the surface 3 to be measured cannot be observed. That is, when the laser beam 5 is projected on the back side of the particle as viewed from the light receiving point B, almost no scattered light is observed, and the scattered light can be observed only when scanning the front side. The pitch angle Δα of the blind spot at which the intensity of the scattered light decreases with respect to the projection angle α (hereinafter, referred to as a blind spot pitch) increases and decreases almost in proportion to the diameter D of the particles. The blind spot pitch Δα is the nth blind spot start angle α
The difference between n and the (n + 1) th blind spot start angle αn + 1 (that is, Δα = αn + 1−αn). Accordingly, the blind spot pitch Δα is detected, and the measured surface computing device 16 can calculate the particle diameter D and the position of the particle from the blind spot pitch Δα.

If the particles are substantially spherical and the blind spot pitch Δα substantially corresponds to the diameter, the measured surface arithmetic unit 16 geometrically changes the particle diameter D to (H ² + C ² ) ^0.5 × Δα.
Approximate value can be calculated by Equation 1. In this equation, C is a horizontal distance from the light projecting position B, and L / 2−R
(R is a radial position). In addition, H and C (or R) in Expression 1 also change during the scanning of the blind spot pitch Δα, but an average value or the like can be used as a representative value (global value) for estimation. Furthermore, the actual ore or coke has an uneven surface, and when a thin laser beam 5 is used, the blind spot pitch Δα may not correspond to the diameter. In such a case, the projection diameter of the laser beam 5 is appropriately changed so that the blind spot pitch Δα representing the particle diameter D is obtained.
Needs to be adjusted to obtain For example, when the unevenness of the surface is extremely severe, the dispersion state of the ore and the coke can be grasped by using the light emission diameter d which is about half the known diameter of the ore or the coke to be used.

The device described above is used as follows. (A) First, a laser beam 5 is projected / received from a light projecting point A and a light receiving point B separated by a certain reference length L, and a measured surface 3 is obtained from a light projecting angle α and a 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 and scanning the surface 3 to be measured, a dead angle pitch Δα at which the intensity of the scattered light is reduced is detected, and the particle diameter D of the particle is calculated from the dead angle pitch Δα.

Preferably, (A) and (B) are performed simultaneously by a single scan. However, if necessary, (A) and (B) can be performed as separate steps.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0022]

According to the apparatus and method of the present invention described above, a beam projecting device, a beam receiving device, and a device for calculating a surface to be measured are provided. By projecting / receiving the laser beam, the vertical height H of the measured surface from the reference length L and the horizontal distance from the projection position are obtained from the projection angle α and the reception angle β with respect to the reference length L by triangulation technology. C can be calculated. In this case, by combining an ultra-high sensitivity light detection technology (equivalent to photon counting), a weak light signal can be accurately detected even in a place where there are many light scattering media.

Further, by applying this technique and detecting the blind spot pitch Δα at which the intensity of the scattered light decreases when scanning the surface to be measured by changing the projection angle α, the blind spot pitch Δα is detected.
The particle diameter D of the particle and its position (vertical height H and horizontal distance C) can be calculated from α.

Therefore, the particle size detection device of the present invention can measure particle size segregation in an environment such as a blast furnace furnace top and in an environment where there are many light scattering media inside, and provide feedback to the operation. It has excellent effects such as being applied.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a particle size detection device according to the present invention.

FIG. 2 is a view showing a principle of measuring 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 Particle size detector 12 Beam light emitting device (light emitting unit) 13 Mirror scanner 14 Beam light receiving device (light receiving unit) 14a Mirror scanner 14b Lens 14c Rotary optical attenuator 14d Light receiver array 15 Light reception control panel 16 Measurement surface calculation device (system control unit)

Claims (3)

[Claims] 1. A beam projection device for projecting a laser beam onto a surface to be measured, and a beam receiving device for receiving scattered light of the laser beam from a projection position on the surface to be measured, The light projecting point of the device and the light receiving point of the beam receiving device are separated by a fixed reference length L, and further include a measured surface calculation device. The vertical height H of the surface to be measured from the reference length L and the horizontal distance C from the light projecting position are calculated from the light receiving angle β, and the surface to be measured is scanned by changing the light projecting angle α to scatter. Detecting the blind spot pitch Δα at which the intensity of light decreases, and calculating the particle diameter D of the particles from the blind spot pitch Δα;
A particle size detection device characterized by the above-mentioned. 2. The particle size detecting device according to claim 1, wherein the particle size D is calculated by an equation of (H ² + C ² ) ^0.5 × Δα by the measured surface computing device. 3. A laser beam is projected / received from a light projecting point and a light receiving point separated by a predetermined reference length L, and a reference length L of the surface to be measured is determined based on a light projection angle α and a light receiving angle β with respect to the reference length L. , And a horizontal distance C from the light projecting position is calculated.
By changing the light projection angle α and scanning the surface to be measured, the blind spot pitch Δα at which the intensity of the scattered light is reduced is detected.
Calculating a particle diameter D of the particle from the particle diameter.