超细气流粉碎分级系统产品粒径的确定与控制

Determination and Control of Product Size for a Ultrafine Milling-Classifying Closed Loop System

建立扁平式超细气流粉碎机与离心式超细空气分级机组成的闭路循环系统。粉碎机将粉碎原料粉碎至粒度 1 0 μm左右 ,分级机使粉碎产品的粒度分布更窄。影响超细气流粉碎分级系统产品粒径的因素有粉碎机的加料速度、分级机叶轮转速及分级机二、三次风量等。通过正交试验及最小二乘法得到分级机分级叶轮转速、粉碎机加料速度、二次风量等对产品粒径影响的回归公式。正交试验结果表明 ,当分级机分级叶轮转速增加时 ,产品粒径减小 ;当原料加入速度增加 ,产品粒径增大 ;二次风量增加 ,产品粒径稍有减少。在回归分析的基础上 ,建立粉碎分级系统产品粒径的计算机控制过程。通过计算机控制粉碎分级系统产品粒径 ,实现粉碎产品粒径的“目标控制”。控制系统的可行性得到试验结果的验证。

The closed loop system which composed by ultrafine pancake jet mill and ultrafine centrifugal air classifier has been set up. The product cut size of jet mill is less than 10 μm. The classifier obtains sharp distribution of end product cut size. Feeding rate of jet mill, rotational speed of classifier, flow rate of secondary air flow and flow rate of third air flow are the factors that affect on the cut size of end product. The optimal operation conditions of the system are discussed by using orthogonal experiment. The relation among rotational speed of classifier, feeding rate of jet mill, flow rate of secondary air flow of classifier and end product cut size has been analyzed by means of regressive method. Based on the results of regressive analysis, the end product cut size control process of ultrafine milling and classifying system is introduced in this paper. The feasibility of computer control system has been testified by the results of experiments.