RU2557330C2 - Method to determine geometric sizes of particles of pellet and/or granulate material in loose layer - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: method to determine geometric sizes of particles of pellet and/or granulate material in a loose layer consists in the fact that a visible area of each particle is formed, by its identification on a video image raster from its corresponding intensity maximum of reflected radiation from its closest minima. Then the sequence of treatment of these areas is set from particles with higher extent of roundedness of the visible area to the lower one, distance is measured from the appropriate maximum of intensity of reflected radiation to minima bordering with visible areas of particles having least extent of roundedness, and thus they determine geometric sizes of particles of pellet and/or granulate material.

EFFECT: increased accuracy of determination of geometric sizes of particles of pellet or granulate material in a loose layer.

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Description

The invention relates to measuring technique, in particular to a method for controlling the technological process of production of granules, for example pellets, granulate, stones or grains, and can be used to determine the geometric sizes of particles of pelletized and / or granular material in a bulk layer.

From the articles "Improving the accuracy of flotation grade measurements by data reconciliation", Haavisto 0., Kaartinen J., Hyotyniemi H., The 6th International Conference on Intelligent Processing and Manufacturing of Materials - IPMM-2007, Salerno, Italy, 24-29 June, 2007 and "Particle size distributions by laser diffraction - Part 1: Sensitivity of granularmatters trength to analytica loperating procedures" F. Storti, F. Balsamo, "RomaTre" University, Roma, Italy, 2009 known methods for solving the problem of assessing particle size distribution bulk material, however, these methods are intended exclusively for laboratory research and cannot be used in mining and processing plants.

A known method for determining the geometric dimensions of particles of pelletized and / or granular material (US Pat. RF. No. 2154814, op. 20.08.2000, bull. No. 23, prototype), which is subjected to direct electromagnetic radiation. Then, a two-dimensional distribution of the intensity of the radiation reflected from the particles is measured, and the maxima and minima, as well as their distance from each other in 8 or more directions, are determined in the intensity distribution of the reflected radiation. From the distances between the maxima and minima of the intensity determine the statistical distribution, which is used as a statistical distribution of the geometric dimensions of the particles. The known method provides a sufficiently accurate measurement of the geometric dimensions of the particles of pelletized and / or granular material, if they are located in a monolayer.

However, if it is necessary to determine the geometrical particle sizes of the pelletized and / or granular material in the bulk layer, this method loses its advantages. In the case of determining the size of the granules in the bulk layer, when the granules of the upper layer partially cover the granules of the lower layers (Fig. 2), even for the particles with a specific shape (pellets, granules whose shape is close to spherical), the known method does not allow determining their true sizes

Thus, the objective of the invention is to develop a method for determining the geometric dimensions of particles of pelletized and / or granular material in a bulk layer, using the well-established idea of using the uneven intensity of radiation reflected from the granules on the surface of the granule and on its boundary, and also taking into account their specific shape.

The problem is solved by the proposed, according to the invention, a method for determining the geometric dimensions of particles of pelletized and / or granular material in a bulk layer, including measuring electromagnetic radiation in the form of its two-dimensional distribution, by fixing it with a video camera in the form of a raster of a video image, and then in the distribution of the reflected intensity radiation determine the maxima and minima, characterized in that they form the visible region of each particle by highlighting it on the raster as images from the corresponding maximum intensity of reflected radiation to the minima closest to it, specify the sequence of processing of these regions from particles with a greater degree of roundness of the visible region to a smaller one, measure the distance from the corresponding maximum intensity of reflected radiation to minima bordering the visible regions of particles with a lower degree roundness, and thereby determine the geometric dimensions of the particles of pelletized and / or granular material.

Currently, the patent and scientific literature does not know the totality of the proposed, according to the invention, features that allow to solve the above technical problem.

So, according to the invention, a method for determining the geometrical sizes of particles of pelletized and / or granular material in a bulk layer consists in initially isolating the maxima and minima in the radiation reflected from each granule (stone, pellet, grain), then a visible region is formed for each particle by highlighting it on the raster of the video image from the corresponding maximum intensity of the reflected radiation to the minima closest to it, with the subsequent determination of the degree of its roundness. Granules having an almost spherical shape and located on the upper layers of the bulk layer, have a visible region in the form of a disk and, accordingly, are characterized by a roundness factor close to 1. The granules located on the lower layers of the bulk are partially covered by upper granules and therefore have a visible region , slightly resembling disks and characterized by a roundness factor of less than 1. Thus, the smaller the roundness factor of the visible region, the lower the corresponding granule in us pnoy weight. That is why it is necessary to set the processing sequence for the visible regions of particles, starting from particles with a greater degree of roundness of the visible region towards its decrease, and take the distance from the maximum intensity of reflected radiation to the minima, which is determined to the boundaries with particles having a smaller factor, as the true granule size the circularity of the visible region, that is, located on the lower layer.

Further details of the invention follow from the example embodiment of the method using the drawings.

They depict:

Figure 1 - installation for producing pellets,

Figure 2 - two-dimensional distribution of intensity,

Figure 3 - maxima and minima of the intensity of the reflected radiation,

Figure 4 - the distance from the corresponding maxima of the intensity of the reflected radiation of the pellets A and B (figure 3) to the minima,

Figure 5 - sizes of pellets, determined in a known manner,

6 - sizes of pellets defined by the proposed method,

Fig.7 is a histogram of the distribution of pellets, the dimensions of which are determined in a known manner,

Fig. 8 is a histogram of the distribution of pellets, the dimensions of which are determined by the proposed method.

The proposed method for determining the geometric dimensions of the particles of pelletized and / or granular material in the bulk layer can be illustrated by the example of installation 1 for producing pellets from iron ore (figure 1). The mixture of iron ore and bentonite to be pelletized is fed through a conveyor belt 5 and a material store 6 to a plate pelletizer 7. The pelletized material is discharged through the next belt conveyor 8. The plate pelletizers 7 are controlled and controlled. The purpose of this control and regulation is to obtain pellets of a certain size from an iron-bentonite mixture. For this, the size of the pellets is measured by measuring unit 2. This measurement can be done when the pellets fall on the conveyor belt 8 or when they lie on the conveyor belt 8. The measuring unit 2 consists of electromagnetic radiation sources uniformly distributed around the circumference, and a video camera. The image supplied by the camera (Fig. 2) is pre-processed and transmitted via a data line 3 to a computer. Evaluation of this transmitted signal occurs in the computer 4 so that there can be obtained information about the distribution of the size of the pellets, which is necessary for regulating the disk pelletizer 7. On the two-dimensional distribution of intensity (figure 2) it is shown that the pellets appear as areas with a higher light intensity. Due to the convex surface in the raster image of the pellets during multidimensional irradiation, for example, by irradiation with three light sources uniformly distributed around the circumference, different reflection of individual regions of the pellet is obtained. So the light from the center of the pellet is reflected more strongly than from the edges. Thus, by conducting threshold processing of the bitmap image (Fig. 2), one can obtain maxima and minima of the intensity of the radiation pellets reflected from the bulk layer (Fig. 3). Next, the processing of the visible areas of the pellets is performed, starting from the areas with the greatest roundness factor in the direction of its decrease. Figure 4 for the pellets A and B shows the measured in 16 directions distances from the centers of the corresponding maxima of the intensity of the reflected radiation to the minima. The table below shows the values obtained.

Table The radii of pellets A and B, measured in 16 directions Measurement number The angle of the direction of measuring the distance from the center of the maximum intensity to the minima The distance from the center of the maximum intensity of the reflected radiation of the pellet A to the minima in pixels The distance from the center of the maximum intensity of the reflected radiation of the pellet B to the minima in pixels one 0 ° 17.00 8.00 2 22.5 ° 8.94 10.44 3 45.0 ° 6.40 21.00 four 67.5 ° 7.28 14.76 5 90.0 ° 8.00 13.00 6 112.5 ° 8.94 10.44 7 135.0 ° 12.04 14.14 8 157.5 ° 16.55 9.49 9 180.0 ° 14.00 9.00 10 202.5 ° 7.28 8.54 eleven 225.0 ° 7.81 10.63 12 247.5 ° 9.49 11.70 13 270.0 ° 9.00 15.00 fourteen 292.5 ° 7.62 16.55 fifteen 315.0 ° 10.00 7.07 16 337.5 ° 18.36 8.54 Average 10.54 12.05

According to the known method for determining the size of the pellets, which consists in averaging the measured distances, the radius of the pellet A will be 10.54 pixels, and the pellet B - 12.05 pixels. Estimating the size of the pellets according to the proposed method, for the pellet A we get the size of 17.68 pixels (only the distances determined for 0 ° and 337.5 ° are averaged, considering the 0 ° direction coinciding with the horizontal axis, since in these directions the pellet A borders with region C, which does not have a maximum intensity and, accordingly, is located on the lowest layer of bulk density), and for pellet B it is 21.00 pixels (the distance defined at an angle of 45 °, since in this direction the pellet B borders on region D, also not having maximum intensity and located on the lower bulk layer).

In Fig.7 and Fig.8 presents a histogram of the distribution of the size of the pellets in the image pixels, calculated in a known manner and proposed, respectively. According to the histogram in Fig. 7, the average size of the pellets is 24.58 pixels, while according to the refined histogram in Fig. 8, this value is 26.03 pixels, which corresponds to a relative error of 6%.

Thus, the technical result of the invention is to improve the accuracy of determining the geometric dimensions of the particles of pelletized and / or granular material in the bulk layer.

Claims (1)

A method for determining the geometric dimensions of particles of pelletized and / or granular material in a bulk layer, comprising measuring electromagnetic radiation in the form of its two-dimensional distribution, by fixing it with a video camera in the form of a video image raster, after which maxima and minima are determined in the intensity distribution of the reflected radiation, characterized in that form the visible region of each particle by highlighting it on the raster of the video image from the corresponding maximum intensity of the reflection radiation to the minima closest to it, determine the sequence of processing of these regions from particles with a greater degree of roundness of the visible region to a smaller one, measure the distance from the corresponding maximum intensity of reflected radiation to the minima bordering the visible regions of particles having a lower degree of roundness, and thereby determine geometrical particle sizes of pelletized and / or granular material.

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