JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 1979, Vol. 3 ›› Issue (07): 1-13.doi: 10.3969/j.jssn.1000-2006.1979.07.002

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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

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.