การประเมินขนาดและรูปทรงของวัสดุเม็ดที่ได้จากเครื่องบดย่อยแบบฟันขบโดยใช้เทคนิคการวิเคราะห์รูปภาพ / กษม สัตยาวุฒิพงศ์ = Evaluation of size and shape of particulate materials ground by a pin mill using the image analysis technique / Kasom Sattayawuthipong
Fractal analysis is recognized as an applicable method for evaluating the shape of particle. However, it has limitation of consuming a great deal of man-hour and time, when analyzed manually. Additionally, such manual method may lead to different results according to human error of the one who carries out the analysis. Therefore, this work has paid attention to develop the application software of image analysis for analyzing particle shape using fractal theory. This software will enhance the analytical work to be faster and make the results more reliable. It will be also applicable for evaluating the feret's diameter of particulate materials. By comparison of particle size distribution of JIS standard powders with those based on feret's diameter and equivalent circle diameter, it was found that the median diameter obtained from image analysis was bigger than the reference value but it was almost the same as that of the mass-based size distribution. The correction of mass-based size distribution, which is converted from number-based size distribution, using a certain value of calibration constant will lead to the median diameter close to the reference number. The present work also studied effect of two major operating variables; feed rate of raw material and aperture of screen, on shape and flowability of ground calcite using a pin mill. From the experimental results, it was found that the flowability of ground calcite increased as the feeding rate was increased because of the increasing of ground calcite size. For the effect of screen aperture it was found that as screen aperture became larger, the flowability of ground calcite became smaller. On the other hand, it was also found that the shape irregularity (which is represented by fractal dimension) increased as the screen aperture was increased.
