南京林业大学学报(自然科学版) ›› 1979, Vol. 3 ›› Issue (07): 1-13.doi: 10.3969/j.jssn.1000-2006.1979.07.002

• 研究论文 • 上一篇    下一篇

雷州桉木的高温干燥试验

  

  1. 广东省雷州林业局;南京林产工业学院木材干燥实验室;中国林业科学研究院热带林业科学研究所
  • 出版日期:1979-12-20 发布日期:1979-12-20

ON THE HIGH-TEMPERATURE DRYING OF EUCALYPTUS WOOD

The Forestry Office of Leizhou, Guangdong ProvinceLaboratory of Wood Drying, Nanjing Technological College of Forest Products Institute of Tropical Forest, Chinese Academy ot Forest Science   

  • Online:1979-12-20 Published:1979-12-20

摘要: 对雷州产的柠檬桉(Eucalyptus citriodora Hook f)、隆缘桉(E.exserta F.Muell)及雷一桉(E.Leizhou No.1)的木材进行了过热蒸汽干燥试验。干燥时干球温度高达110℃,湿球温度保持100℃。结果表明,隆缘桉与雷一桉比柠檬桉难干,心材比边材难干。 试验前曾运用分析弦向干缩系数对径向干缩系数比值的方法,预测在干燥期间木材可能发生应力开裂的含水率阶段。分析表明,在木材平均含水率降至30%以前,隆缘桉与雷一桉木材的弦,径向干缩系数比的比值远高于柠檬桉,心材的比值远高于边材。分析的预测和干燥质量相符合,即,隆缘桉与雷一桉板材中出现的应力开裂显然地多于柠檬桉;心材部分出现的应力开裂显然地多于边材。 对柠檬桉的气干材与高温干燥材的一部分力学性质作了对比测定。结果是:两种干材的顺纹抗压强度、静曲抗弯强度和静曲弹性模量的差别不明显,但高温干燥材的冲击韧性比气干材的小6%。

Abstract: Three kinds of eucalyptus woods from Leizhou, namely, Eucalyptus citriodora Hook f., E. exserta F. Muell, and E. Leizhou No. 1 were dried in superheated vapor with dry-bulb temperature as high as 110℃, while the wet-bulb temperature kept 100℃. Results of drying experiments showed that lumbsrs of E. exserta and E. Leizhou were much refractory than those of E. Citriodora and that heartwood was much refractory than sapwoodA method under the term "analysis of the ratio of tangential shrinkage coefficient to radial shrinkage coefficient" was used to predict the probable MC range within which the stress checks would appear in wood. It was known from the analysis that when wood was dried from 80-60 per cent MC to 30 per cent MC values of the ratio were much higher for E. exerta and E. Leizhou than for E. citriodora, and that values of the ratio were much higher for heartwood samples than for sapwood samples. The prediction of analysis corresponded well with the final drying quality that there were apparently much more stress checks appeared in lumbers of E. exerta and E. Leizhou and especially in the heartwood part.Several kinds of strength properties of E. citriodora were tested for both air-dried wood and HT-dried wood. Referring to strength properties of compression parallel to grain, static bending and modulus of elasticity, it was found that the differences between the air-dried wood and the HT-dried were not significant. However, the average strength value of impact bending of the HT-dried was 6 per cent lower compared with that of the air-dried wood.