小径木核桃楸锯材干燥工艺的选择

Selection of Drying Technology on Small-diameter Manchurian Walnut Timber

对小径木核桃楸锯材进行三周期的间歇式干燥 ,小径木核桃楸年轮宽度较宽、胞腔直径较大、胞壁率及胞壁厚度较小 ,在干燥过程中细胞腔中的自由水比较容易排出 ,干燥速度较快 ;小径材的弦、径向干缩系数均比成熟材大 ,小径木核桃楸的干缩系数约为成熟材的 3倍 ,在干燥过程中极易产生干缩变形 ;小径木核桃楸径切材的抗剪切力均大于弦切材。根据木材特性分析 ,采用间歇式干燥方式可提高锯材的干燥质量。

Small-diameter Manchurian walnut timbers were dried with intermittent heating method for three cycles. The results show that the free water in cell cavity drains more easily and drying speed is more quickly in the course of drying for those timber with wider ring width, larger cell diameter, less cell space ratio and cell wall thickness. The coefficients of tangential shrinkage and radial shrinkage of small-diameter timber a larger than those of adult timber, and the coefficient of shrinkage of the former is three times as much as the latter. Therefore deformation by shrinkage for small-diameter timber occurs easier during drying. For small-diameter timber, the shearing strengths of radial timber are larger than that of tangential timber. According to wood characteristics, drying with intermittent heating method can improve the qualities of timber.