图像沉降法测量颗粒粒度的研究

IMAGE-SEDIMENTATION TECHNIQUE FOR PARTICLE SIZE ANALYSIS

本文提出了图像沉降法，用于快速测量颗粒的粒度分布．该法采用具有2048个元素的图像传感器，沿着沉降高度测量消光强度，消光图像可显示于屏幕上，因而可以观察和监视颗粒的沉降过程．由液体（例如水）表面至任一给定点之间的高度可用图像技术精确地测量，不必借助移动光来或沉降池等附加机械装置．对于粒度为4.5μm的SiC粉末，本法的测量时间仅为5min；为国外同类仪器测量时间的1／5.本文最后给出了一些测量结果．

A technique called ' image- sedimentation', which based on the applicationof Stokes' law to suspensions and image technique, is proposed for rapid analysis of particle size distribution. A parallel beam of visible light is transmitted through a cell containingsedimenting particles, and the attenuated light is measured with an image sensor with 2048 photo-detectors, and at the designated time instants the images of attenuated light are displayed on the screen and also stored for postprocessing. The settling height between any given point to be measured and the liquid surface can be measured accurately by using the image techniquewithout additional mechanical device to move either the light beam or the glass cell containingthe suspension. Consequently the total time required for the determination of particle size distribution for carborundum powder having a medium diameter of 4.5 μm takes only about five minutes in contrast to twenty or more minutes by other instruments based on the sedimentation principle.