榆木锯材常规干燥基准的优化研究

Optimization of conventional drying schedule of converted elm timber

榆木属于难干硬阔叶材,易出现干燥缺陷。针对50 mm厚的榆木锯材,根据其干燥过程中存在的问题,通过应力检测调整中间处理的次数与时间,对榆木锯材常规干燥基准进行了优化;并利用称重法对探针测得的含水率进行修正,得出补偿函数,以保证干燥基准的正确实施。结果表明,按优化后的干燥基准对试材进行干燥,含水率从60.0%±3.0%降至10.0±1.0%,干燥周期由626h缩短至506h,共节约19.17%的干燥时间;干燥后试材厚度上含水率偏差和残余应力分别减小46.73%和33.49%,各项质量检测指标基本达到国家一级标准。

Elm hardwood is difficult to dry and prone to drying defects. The drying schedule for elm wood of 50 mm thickness was optimized by means of adjusting the duration and time in intermediate treatment to solve the problems occured during the drying process. In addition, for ensuring the proper implementation of drying sched- ule, the value of moisture content measured by probe method was corrected through comparing it with the value measured by weighing method. The results showed that： in the optimized drying schedule the drying time de- creased from 626 hours to 506 hours, saved by 19.17%. Moreover, the moisture content distributed deviation and residual stress tested on the orientation of the samples thickness were reduced by 46.73% and 33.49%, respectively. Most indicators for quality test reached the national first level standard.