文献类型：期刊文献

中文题名：机械预处理对落叶松原木常规干燥特性的影响

英文题名：Effects of mechanical pretreatment on the conventional drying characteristics of larch logs

作者：褚江依[1] 王斯栋[1] 江京辉[1] 王朝晖[1]

第一作者：褚江依

机构：[1]中国林业科学研究院木材工业研究所,北京100091

年份：2022

卷号：42

期号：4

起止页码：162-169

中文期刊名：中南林业科技大学学报

外文期刊名：Journal of Central South University of Forestry & Technology

收录：CSTPCD;;北大核心:【北大核心2020】；CSCD:【CSCD_E2021_2022】；

基金：国家重点研发计划项目(2018YFD1101002)。

语种：中文

中文关键词：机械预处理;落叶松;原木;常规干燥;干燥质量

外文关键词：mechanical pretreatment;larch;log;conventional drying;drying quality

分类号：S781.3;TK6

摘要：【目的】探究不同机械预处理方法对于落叶松原木常规干燥的干燥速率、干燥质量、抗压强度的影响,得出一种较佳的干燥工艺,为原木应用提供理论支撑。【方法】以华北落叶松为研究对象,取4株落叶松,截取24段1 m长、径级14~16 cm间的原木。其中,12段原木去皮,12段原木不去皮,分别做单切口、双切口、中心钻孔和蜂窝式钻小孔的机械预处理,对处理后的原木常规干燥。【结果】4种机械处理后原木干燥速度相差不大,单切口处理试样速率最快为0.052%·h^(-1),双切口速率为0.044%·h^(-1),两种切口处理方式相较于两种钻孔处理提速0.014%·h^(-1)。其中,中心钻孔速率0.032%·h^(-1),钻小孔速率0.036%·h^(-1)。中心钻孔和双切口处理在减少端表裂数量和长度效果明显,其中双切口处理的表裂总长度为81.25 cm,相较于单切口处理的总长227.9 cm减少了64.3%。双切口相较于单切口表裂数量降低了35.3%,双切口处理对长表裂的减少尤为明显,降低75%;钻小孔干燥缺陷严重,表裂总长536.9 cm为双切口的3.4倍。中心钻孔处理原木虽然去除了部分心材,但对原木结构破坏小,抗压强度没有明显下降;而单切口和双切口处理的原木抗压强度均低于中心钻孔材。【结论】对于切口处理,增加切口数量可以降低含水率梯度,减少开裂的数量和长度。中心钻孔处理增大了与干燥介质接触面积,应力得到进一步释放,显著减少了端裂。钻小孔处理对原木结构破坏过大,干燥质量差,该工艺有待于进一步优化。
【Objective】The study was aimed to explore the effects of different mechanical pretreatment methods on the drying rate,drying quality and compressive strength of conventional larch logs,and obtain a better drying protocol to provide theoretical support for the application of logs.【Method】Taking Larix principis-rupprechtii as the research object,4 Larix principis-rupprechtii trees were selected,and 24 logs with a length of 1 m and a diameter of 13-18 cm were intercepted.Among them,12 sections of logs were peeled and 12 sections of logs were not peeled.The mechanical pretreatments of single incision,double incision,central drilling and cellular drilling were performed respectively,and the processed logs were routinely dried.【Result】The drying speed of the logs after the 4 mechanical treatments showed no significant difference.The sample rate of the logs with the single incision treatment was the fastest with 0.052%/h,and that of the double incision treated logs was 0.044%/h.The drying speed of the logs after the incision treatments was increased by 0.014%/h compared with that of the drilled logs.The central drilling and double incision treatment can significantly reduce the number and length of the end surface cracks.The total length of the surface cracks with the double incision treatment was 81.25 cm,which was 64.3%less than that of the single-cut logs.Compared with the single incision,double incision reduced the number of surface cracks by 35.3%,and double incision reduced the number of long surface cracks by 75%.Drilling showed serious drying defects.The total length of the surface crack was 536.9cm,which was 3.4 times that of the double-cut logs.Although part of the heartwood was removed by central drilling,it did little damage to the log structure and did not significantly reduce the compressive strength.The compressive strength of the logs treated with incisions was lower than that of the drilled logs.【Conclusion】For incision treatment,increasing the incision number can reduce the water content gradient,and the number and length of cracks.The central drilling treatment increases the contact area with the drying medium,which further releases the stress and significantly reduces the end cracks.The drilling treatment will cause too much damage to the log structure and lead to poor drying quality.Thus,the process needs to be further optimized.