干燥前汽蒸处理对柞木板材干燥时间和干燥质量的影响

Effect of Steaming Prior to Drying on the Drying Time and Drying Quality of Oak Boards

在干球温度65℃和相对湿度100%条件下,干燥前蒸汽处理25.4mm厚度柞木板材4h后,将其与对照试件一起实施了常规干燥。试验结果表明:1)由于渗透性提高,处理材表层受限于较大压缩应力导致了较多木材纤维素的结晶化,降低了干燥速度,结果干燥时间延长了20%;2)因汽蒸处理期间抽提物质逐步由材内向材面移动,处理材弦/径向干缩率比明显大于对照材,差异干缩应力增大,干燥变形加大了5.88%。因此,为了节省能量消耗和减少干燥变形不应对柞木板材实施预汽蒸处理。

Steamed 25.4mm thick oak lumbers in saturated condition at 65℃ for 4 hours prior to drying were conventionally dried together with controls.The experiment indicated that：1） drying of treated samples delayed drying time by 20 percent because of the increased crystallinity inside the shells of the samples due to the larger compressive stress originated from the improved permeability of wood during steaming,2）the drying warp of the steamed samples increased by 5.88 percent because of enlarged differential shrinkage stress due to tangential/radial shrinkage ratio being increased,which caused by the extractive removing from the inside wood to the outside wood during steaming.Therefore,presteaming should not be applied to oak boards in order to save energy consumption and reduce the warp of wood.