研究了微波预热对中密度纤维板板坯中水分和温度分布规律的影响.结果表明:微波预热处理使板坯形成表层含水率高,芯层含水率低的含水率梯度,减小预压高度、增加微波预热时间、适当调高板坯初含水率有利于在板坯中形成表层含水率略高于芯层的含水率梯度;微波预热处理使板坯形成芯层温度高,表层温度低的温度梯度,形成了驱动内部水分向表层渗透的蒸汽压差,加速水分的迁移,使板坯中的水分重新分布;微波预热处理减少板坯的热压工序,缩短热压时间,实现了生产线生产能力的提高和单位产量能耗的降低.%An experiment was conducted to study the moisture and temperature distribution of medium-density fibreboard (MDF) mat after microwave preheating. Result showed that the microwave preheating made the mat form a moisture gradient with the high moisture of the edge layer and the low moisture of the central layer. And it could also reduce the preloading height, increase the microwave preheating time, and suitably raise the initial moisture content, which helped to form the moisture gradient. Moreover, the microwave preheating made the mat form a temperature gradient with the high temperature of central layer and the low temperature of the edge layer, which caused the vapor pressure difference. Thereby the internal water permeated to the surface layer and the velocity of water moving increased, which resulted in the redistribution of water in the mat. The microwave preheating could reduce the mat heating process and cut down the heating time, which realized the improvement of production capacity and the reduction of energy consumption per unit of production.
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