JPH0623687B2 - Particle size distribution measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an apparatus for measuring the particle size distribution of iron ore, coke, sinter or the like as a blast furnace charging raw material.

[Prior art]

The particle size of various raw materials charged into the blast furnace is greatly related to the air permeability in the furnace, and it is important to know the particle size distribution of the raw material immediately before the blast furnace is charged in order to stabilize the operation of the blast furnace.

FIG. 4 is a schematic diagram showing the structure of the particle size distribution measuring device disclosed in Japanese Patent Laid-Open No. 54-92389. In the figure, 31 is a hopper that stores the raw material, and the raw material is continuously fed from the hopper 31.
After being discharged and conveyed on the conveyer 33, 32 is dropped into the receiving hopper 34 from these end portions with a constant drop. The falling raw material 32 is configured to be horizontally imaged by a TV camera 35, and the TV camera 35 is connected to a computer 37 via a TV camera control device 36.
The TV camera controller 36 has a monitor 38 for displaying a photographed image,
A monitor 39 for displaying the measurement result of the particle size distribution is connected to the computer 37. In addition, the TV of the fall path of the raw material 32
An illumination device 40 using a stroboscope or the like for illuminating the raw material 32 is installed on the opposite side of the camera 35, and light emission is controlled by a computer 37.

In the device as described above, the raw material 32 continuously falling by the TV camera 35 is imaged by the light emission of the lighting device 40, and is captured as a still image. And from this still image computer 37
The area, number, particle size, and weight ratio of the particles of the raw material 32 are calculated according to the above, and the particle size distribution is measured based on the calculated values.

Further, a device is known in which the particle size distribution of the falling raw material 32 is measured by using a one-dimensional image sensor camera having a one-dimensional image sensor equipped with a lens in place of the TV camera 35 in the above device. FIG. 5 is a schematic diagram showing a main part of the configuration. The falling area of the raw material 32 falling in the arrow direction is a rod-shaped light source 51 such as a fluorescent lamp instead of the lighting device 40.
The rod-shaped light source 51 is extended in the horizontal direction parallel to the width direction of the falling area of the raw material 32. A one-dimensional image sensor camera 54 including a lens 52 and a one-dimensional image sensor 53 is arranged on the opposite side of the rod-shaped light source 51 so as to face the falling area of the raw material 32.
The one-dimensional image sensor 53 is arranged in parallel with the rod-shaped light source 51 through the falling area of the raw material 32, and the light from the rod-shaped light source 51 is condensed by the lens 52 to form the one-dimensional image sensor 53.
Imaged above. The one-dimensional image sensor 53 is an image memory
The image memory 55 is connected to the image processing device 56. When the raw material 32 falls between the rod-shaped light source 51 and the one-dimensional image sensor camera 54 according to the above configuration, the light from the rod-shaped light source 51 at that portion is blocked, so that the size of the raw material 32 from the one-dimensional image sensor 53 increases. A dark area signal proportional to is output.

FIG. 6 is an explanatory view of the photographing operation by the one-dimensional image sensor camera 54, and the one-dimensional image as shown by the scanning number 0 by the one-dimensional image sensor 53 until the lower end of the raw material 32 reaches the field of view of the camera. There is no dark part in the output signal of the sensor 53. When the lower end of the raw material 32 reaches the field of view of the camera, a slight dark portion appears as shown in scanning number 1, and when the central portion of the raw material 32 enters the visual field of the camera, a large dark portion as shown in scanning number 4 causes a one-dimensional image sensor. It occurs in the output signal of 53. As the raw material 32 moves out of the field of view of the camera, the dark area also decreases, and when the raw material 32 is completely out of the field of view of the camera as shown in scan number 7, the one-dimensional image sensor
The dark part disappears from the output of 53. By sequentially storing the changes in the signal of the one-dimensional image sensor 53 in the image memory 55, a two-dimensional image 60 corresponding to the shape of the raw material 32 can be obtained. Although it is extremely shown in a mosaic shape in this figure, a smooth image can be obtained by photographing with a high-resolution one-dimensional image sensor.

By performing known image processing by the image processing device 56 from the image 60 obtained in this way, the particle size of the raw material 32 is obtained, and the particle size distribution is measured.

In this latter device, the field of view of the camera is one-dimensional, and when compared to the former two-dimensional image capturing device, non-uniformity of illuminance within the imaging region can be suppressed, so there are few measurement errors due to it, and dust prevention is possible. There is an advantage that countermeasures are easy.

[Problems to be Solved by the Invention]

By the way, both the above-mentioned conventional devices have the following problems. FIG. 7 is an explanatory diagram thereof, and FIG.
(a) shows the raw material group which continuously falls in the arrow direction, and the image obtained by capturing this moment is FIG. 7 (b). 7th
In the figure (b), the raw material 61 at the upper end is not entirely within the imaging area, and the particle size of each raw material is inaccurate when calculated from this image, so an object that partially protrudes from the edge of the image is usually found. Are excluded from the measurement target.

However, the larger the diameter of the object, the higher the probability of protruding from the edge of the image, and the higher the probability of being excluded from the measurement target. On the other hand, in blast furnace raw materials, the larger the diameter, the smaller the quantity and the weight of even one piece, so the average particle size in terms of weight greatly differs depending on whether or not one piece is included in the measurement target. There is.

In order to avoid such a problem, it is conceivable to use two cameras to alternately take images so that the fields of view are overlapped. However, it usually takes more time for image processing than the time for taking images. Therefore, the capacity of the memory for storing the captured image becomes enormous, which is not realistic. Although it is possible to intermittently drop the raw material, it is difficult to drop the raw material for an extremely short time, and the amount to be measured becomes small, which is not preferable.

The present invention has been made in view of such circumstances, suppresses the large diameter objects that affect the particle size distribution from being excluded from the measurement target, and accurately determines the particle size distribution from small diameter to large diameter objects. It is an object of the present invention to provide a particle size distribution measuring device capable of measuring.

[Means for Solving the Problems]

The particle size distribution measuring apparatus according to the present invention is a two-dimensional image obtained by time-sequentially capturing an object group moving in one direction with a one-dimensional image sensor camera extending in a direction orthogonal to the moving direction. A device for measuring the particle size distribution of the object group from the data, wherein the one-dimensional image data in the moving direction of the object group is accumulated at a resolution substantially equal to that of the one-dimensional image sensor camera to obtain two-dimensional image data. Image data accumulating means, and second image data accumulating means for accumulating two-dimensional image data by accumulating one-dimensional image data in the moving direction of the object group at a resolution lower than the resolution of the first image data accumulating means. And a means for obtaining a particle size distribution of the object group based on the two-dimensional image data accumulated by the first and second image data accumulating means, respectively.

[Action]

In the two-dimensional image data obtained by the first image data storage means, the image of the object group to be moved has a resolution of the one-dimensional image obtained by the one-dimensional image sensor camera and a resolution in the moving direction of the object group that are substantially equal to each other. Things are formed.

In the two-dimensional image data obtained by the second image data storage means, an image of the object group to be moved is formed with a resolution in the moving direction of the object group lower than that of the first image data storage means.

As a result, a small-diameter object is detected mainly from the two-dimensional image data of the first image data accumulating means, and a large-diameter object is mainly detected from the two-dimensional image data of the second image data accumulating means. The overall particle size distribution is determined.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings illustrating the embodiments. FIG. 1 is a schematic block diagram showing the configuration of a particle size distribution measuring device according to the present invention. Raw material to be measured
16 is stored in the hopper 1 similarly to the conventional device shown in FIG. 4, and is continuously discharged from the hopper 1 in a predetermined cut amount, and after being transferred to the transfer conveyor 2, it is fixed from the end thereof. Is dropped into the receiving hopper 3 and conveyed to be loaded into a blast furnace (not shown). The raw material 16 being dropped is the rod-shaped light source 4 extending in the horizontal direction in parallel with the width direction of the falling area of the raw material 16 as in the conventional apparatus shown in FIG.
And is photographed by a one-dimensional image sensor camera 5 arranged in parallel with the rod-shaped light source 4 on the opposite side through the falling area. The one-dimensional image sensor camera 5 is configured such that the camera control device 6 controls the photographing cycle, that is, the scanning cycle of the image sensor.

The output signal of the one-dimensional image sensor camera 5 is given to the image memory 7 which is the first image data storage means and the signal thinning-out device 8, respectively, and the signal thinning-out device 8 together with it outputs the second image data storing means. The output signal is given to the compressed image memory 9 constituting the. Image memory 7 is 1
The signal from the three-dimensional image sensor camera 5 is accumulated and a two-dimensional image having a horizontal and falling direction ratio of 1: 1 is stored. Here, the scanning cycle of the image sensor is set in the camera control device 6 so that the resolution in the falling direction of the two-dimensional image becomes equal to the resolution in the horizontal direction, that is, the resolution of the one-dimensional image sensor camera 5. From the image stored in the image memory 7, the particle size distribution of the small diameter raw material is mainly obtained.
In this case, it is impossible to measure all of the falling raw materials, but the small-diameter raw material is much larger in number than the large-diameter raw material, and therefore the representativeness of sampling is sufficient.

The signal thinning device 8 thins the signals from the one-dimensional image sensor camera 5, and the thinning rate can be changed according to the required accuracy and the expected maximum diameter of the raw material 16. As a result, the signals from the one-dimensional image sensor camera 5 are thinned out and stored in the compressed image memory 9, so that the resolution in the falling direction is lower than that of the image memory 7, and the two-dimensional image compressed in the falling direction is obtained. Is memorized. Signal thinning device 8
The thinning rate is set to a rate that is normally 2 to 20 times the scanning cycle of the image sensor stored in the image memory 7. In this way, from the image compressed and stored in the compressed image memory 9, the particle size distribution of the large-diameter raw material is mainly obtained. That is, in the compressed image, the small-diameter raw material is difficult to detect, but the large-diameter raw material is detected. The measurement target area is longer than the measurement target area stored in the image memory 7 in the falling direction. Therefore, it is possible to measure a large-diameter raw material, which has a small number and is highly likely to be excluded at the upper and lower end portions of the image storage area of the image memory 7, without omission of detection.

Reference numerals 10 and 11 denote monitors connected to the image memory 7 and the compressed image memory 9, respectively, and display images stored in the memories. The image memory 7 and the compressed image memory 9 are connected to the image processing device 12, and the image processing device 12 processes the signals of each memory to obtain the area, number, and particle size of the small diameter and large diameter raw materials in each image.

The image processing device 12 is connected to a computer 13, and the computer 13 calculates the weight from the particle size and the number obtained by the image processing device 12, obtains the weight ratio within a predetermined particle size range, and calculates the particle size distribution. Index. This particle size distribution is computer 13
It is displayed in the form of a histogram by a CRT 14 connected with.

Now, the operation of measuring the particle size distribution by the apparatus of the present invention configured as described above will be specifically described. Usually, the blast furnace raw material has a particle size of about 3 mm to 100 mm. This raw material is used, for example, by using a 1000-element one-dimensional image sensor camera 5.
To shoot with a resolution of 0.6 mm, the field of view of the camera is 600 mm
You can set it to.

Next, when the raw material 16 is dropped from a height of 0.5 m from the camera installation position, it passes through the field of view of the camera 5 at a speed of about 3 m / sec. In order to take an image of the raw material 16 in the falling direction with a resolution of 0.6 mm, it is necessary to take an image every time it falls by 0.6 mm.
In other words, it is necessary to take a picture every 0.6 mm / 3000 mm / sec = 0.2 msec. If the number of pixels in the image memory 7 is 1000 × 1000,
As shown in the explanatory view of FIG. 2, the raw material 16 falling within a range of 600 mm × 600 mm, which falls in 0.2 msec × 1000 = 0.2 sec, is a measurement target. Here, for example, for a raw material having a particle size of 100 mm, a part of the raw material protrudes from the image storage area within 50 mm of the upper and lower ends of the image storage area, so it is stochastically (50 + 50) mm / 600.
The number of mm = 1/6 is excluded from the measurement target. Incidentally, in the width direction of the falling area, the raw material can be prevented from protruding from the image storage area by appropriately setting the carrying width of the carrying conveyor 2.

FIG. 3 is an explanatory view of the stored image, and FIG. 3 (a) is an image stored in the memory 7, which is obtained by photographing the falling raw material group 16 for 0.2 seconds. As described above, since the resolution in the falling direction is 0.6 mm, the small-diameter raw material having the particle diameter of 3 mm can be detected without fail. On the other hand, FIG. 3 (b) shows a compressed image stored in the compressed image memory 9, which is obtained by thinning out a signal photographed every 0.2 msec, for example, once every 10 times. . In this compressed image, it was taken 6000 mm in the falling direction, and the probability that a large diameter raw material with a particle size of 100 mm will protrude from the upper and lower ends of the image storage area is
(50 + 50) mm / 6000 mm = 1/60, which is significantly lower than the case of the image memory 7 as a non-measurement target.

In this case, how the small-diameter raw material is memorized will be memorized once every 10 times, so it will be memorized each time it falls by 6 mm. Therefore, there is a high probability that a small diameter raw material of 3 mm will not be remembered. However, since the compressed image memory 9 mainly performs image processing on large-diameter raw materials, there is no problem.

In this way, the image memory 7 mainly stores the small-diameter raw material, and the compressed image memory 9 mainly stores the large-diameter raw material. Based on the detection results of the raw material particle diameters obtained from both images, a wide range from the small diameter to the large diameter is obtained. The particle size distribution of the entire raw material can be measured with high accuracy.

Since the compressed image memory 9 compresses the image in the falling direction of the raw material 16, it is not necessary to drop the raw material 16 for an extremely short time even during intermittent operation, and the amount to be measured does not significantly decrease.

Further, in the present embodiment, the second image data storage means is configured to store in the compressed image memory 9 the signal obtained by thinning out the photographing signal of the one-dimensional image sensor camera 5 by the signal thinning-out device 8. The present invention is not limited to this, and for example, a one-dimensional image sensor camera that captures the falling raw material at an imaging cycle longer than the imaging cycle of the one-dimensional image sensor camera 5 may be separately provided, and the imaging signal may be directly stored in the memory. .

〔effect〕

As described above, in the particle size distribution measuring device according to the present invention,
A small-diameter object is obtained from a two-dimensional image in which one-dimensional image data in the moving direction of the object group is accumulated at a resolution substantially equal to that of the one-dimensional image sensor camera, and a large-diameter object is reduced in the moving direction of the object group. Two-dimensional image data stored
Since it is configured to mainly detect each from a three-dimensional image, the probability that a part of a large-diameter object will protrude from the image and be out of the measurement target is a two-dimensional image that is accumulated for a small-diameter object as in the past. It is significantly lower than the case of detecting only by using. As a result, regardless of large or small diameter,
With sufficient representativeness, it is possible to measure the particle size distribution of raw materials with high accuracy,
The present invention has excellent effects such as improved reliability.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the configuration of a particle size distribution measuring device according to the present invention, FIG. 2 is an explanatory diagram of an image storage area, and FIG.
FIG. 6 is an explanatory diagram of a stored image, FIGS. 4 and 5 are schematic diagrams showing the configuration of a conventional device, FIG. 6 is an explanatory diagram of a photographing operation of a one-dimensional image sensor camera, and FIG. 7 is a problem of the conventional device. FIG. 1 ... Storage hopper, 4 ... Rod light source, 5 ... One-dimensional image sensor camera, 7 ... Image memory, 8 ... Signal thinning device, 9 ... Compressed image memory, 12 ... Image processing device,
16 ... Raw material

Claims (1)

[Claims] 1. A two-dimensional image data obtained by time-sequentially capturing an object group moving in one direction by a one-dimensional image sensor camera extending in a direction orthogonal to the moving direction. In a device for measuring a particle size distribution, first image data storage means for storing two-dimensional image data by accumulating one-dimensional image data in a moving direction of an object group at a resolution substantially equal to that of the one-dimensional image sensor camera. , Storing the one-dimensional image data in the moving direction of the object group at a resolution lower than the resolution of the first image data storage means 2
A second image data accumulating means for obtaining three-dimensional image data; and a means for obtaining a particle size distribution of the object group based on the two-dimensional image data respectively accumulated by the first and second image data accumulating means. A particle size distribution measuring device characterized by: