预处理对榆木锯材干燥效果及尺寸稳定性的影响

探讨了25 mm厚榆木锯材的常规干燥工艺,并在此基础上分析了100℃水热处理与汽蒸处理对干燥周期、干燥质量和尺寸稳定性的影响,旨在丰富榆木干燥理论,为高效常规干燥工艺提供科学依据。结果表明:干燥基准Ⅲ的工艺最佳,干燥周期为177 h,干燥质量满足国家锯材干燥质量标准一级指标;预处理可在保证榆木锯材干燥质量的前提下缩短干燥周期;与未处理材相比,预处理材的干缩率、干缩系数与湿胀率均有不同程度增加,其干裂势有较大幅度的降低,抗干缩(湿胀)率略有降低;汽蒸处理材的吸水率均高于未处理材,水热处理材的吸水率均低于未处理材。

Effect of Pre-treatment on Drying Consequence and Dimensional Stability of Elm

Basing on the determination of conventional drying technology of 25-mm elm, we studied the effect of 100℃pre-boil-ing and pre-steaming on drying period, drying quality and dimensional stability of timber to enrich drying theory and scien -tific evidence for efficient conventional drying technology of elm .The drying schedule Ⅲwas the optimal drying technolo-gy, drying period of that was177 h, and the drying quality met the national lumber first drying quality index .Drying period of pre-treated timber was shortened , and the drying quality was guaranteed .Dry shrinkage , dry shrinkage coefficient and wet inflate rate of pre-treated specimens were significantly decreased compared to the untreated ones , but shrinkage rate , shrinkage coefficient and bulking rate were contrary .Anti-dry-shrinkage of pre-treated specimens mirrored a little reduction . Water absorption of pre-boiled samples was lower than that of untreated ones , while that of pre-steamed specimens was higher.