粒度粒形分布特点对板材锯切和油漆砂光粉尘流动性的影响

Influence of Size and Shape Distribution on the Flowability of Particles Emitted during Panel Cutting and Paint Sanding

【目的】对板式家具生产性粉尘的粒度粒形进行研究,分析粒度粒形分布特点对粉尘流动性的影响,为板式家具生产线除尘系统的设计与运行参数优化提供基础数据。【方法】以板式家具生产中板材锯切和油漆砂光粉尘为研究对象,采用图像法对粉尘的面积等效直径、长宽比、粗糙度、坚固度和钝度等粒度粒形参数进行分析,归纳粉尘的粒度粒形分布特征,分析其对流动性的影响。【结果】锯屑和砂光粉主要由粒径小于100μm的小颗粒构成,具有较强的悬浮和扩散能力。与锯屑相比,砂光粉的尺寸更细小,分布相对集中,具有更强的黏附性和凝聚性。锯屑和砂光粉的宏观形态不规则,具有长宽差异较大的几何比例,个体间形态差异大;但在介观上,二者都具有高度平整的表面织构,并且2种颗粒的形态都随粒度减小而趋于规则。与砂光粉相比,锯屑颗粒的形态不规则性更强,颗粒间的形态差异也更显著。【结论】锯屑和砂光粉都属于流动性差的颗粒,与二者的粒度粒形特征密切相关。2种粉尘的尺寸较小,颗粒间的黏附性凝聚性较强,限制了粉尘的总体流动性。在形态上,大颗粒的形态不规则,在运动中易相互咬合并在颗粒间形成孔隙;小颗粒虽然形态上相对规则,但易填充在大颗粒间的孔隙中,流动性也受到限制。

【Objective】In order to lay a foundation for the optimized wood dust,the size and shape distribution of particles emitted in panel furniture manufacturing was studied to clarify their influence on the particle flowability.【Method】The particle samples were collected in the panel cutting and paint sanding processes.The area diameter,aspect ratio,roundness,solidity and bluntness of the particles were investigated by means of image analysis to characterize their size and shape distribution.The influences of size and shape distribution on the particle flowability were then analyzed.【Result】The sawdust and sanding dust were mainly composed of fine particles with diameters of less than100μm,which could float long and travel wide in the air.Compared to the sawdust,the size of the sanding dust was smaller and the size distribution was narrower,making them more cohesive and adhesive.In terms of macroscopic shape,the sawdust and sanding dust were both irregular particles,exhibiting small aspect ratios and great inter-particle shape variation.However,they presented highly smoothed surface in mesoscopically,and the shape irregularity decreased with the falling particle size.Compared to the sanding dust,the sawdust showed higher shape irregularity and greater inter-particle shape variation.【Conclusion】The flowability of both particles was poor,which highly correlated with their size and shape characteristics.The small size of both particles causes high cohesive and adhesive forces,which in turn lower the flowability of the particles.With respect to the particle shape,the irregular larger particles tend to interlock with each other,while the relatively regular smaller particles are often trapped in the voids formed between the larger ones.This structure restricts the flow of particles with all sizes.