Effect of Pre-Steaming on Deresination Rate and Drying Quality of Radiata Pine Lumber
The sawn timber of radiata pine(Pinus radiata)was degreased and dried by combining pre-steaming and conventional drying.The effects of pre-steaming on the moisture content(MC),the deresination rate,and the drying quality of radiata pine sapwood and heartwood were analyzed.The results showed that after the pre-steaming treatment,the drying time of heartwood shortened but the drying time of sapwood had little change.Because the lower resin content and higher permeability of sapwood,the pre-steaming had a little effect on the deresination rate of sapwood.The deresination rate of the sapwood was about 60%in both with and without pre-steaming techniques.For heartwood,pre-steaming treatment promoted the migration of resin,so that the deresination rate of the pre-steaming group was higher than that of the control group.However,the initial MC of the heartwood was low and the permeability was poor,so the deresination rate of heartwood was lower than that of sapwood.Both the pre-steamed group and the control group showed good anti-resin-exudation.The visual quality of the pre-steaming group was better than that of the control group.In conclusion,pre-steaming treatment had no significant effect on the drying quality of sapwood and heartwood.Special attention was paid to prevent the distortion caused by the spiral texture of heartwood in the process of wood drying.
国家科技期刊平台
NSTL
万方数据
维普
