木材电热远红外线干燥内部温度的实验研究

EXPERIMENTAL RESEARCH ON INTERNAL TEMPERATURE OF LUMBER DRIED BY ELECTRIC HEAT FAR INFRARED RADIATION

用电热远红外线干燥大量木材,发现木材内部温度高于外部温度的现象,并作了初步分析:(1)在特定条件下,木材干燥内温高于外温的快慢时间,取决于木材的含水率与厚度,厚度、含水率大者则慢,反之则快。(2)随树种材质而不同,材质致密者慢,疏松者快。(3)木材内外温差的大小,则与上述条件相反。远红外线干燥木材,主要是木材纤维素、木素和水分等强烈地吸收远红外线电磁波,其吸收率可达90％以上;辐射、吸收、再辐射、再吸收,如此循环,促进了木材含水率与干燥温度均内高外低,方向一致,达到了同步干燥目的。蒸发木材中水分1kg耗电1kwh。

It is found that the internal temperature of the lumber dried by electric heat far infrarea radiation may be higher than the external temperature. The primary analysis is made. Under a particular condition, the rate at which the lumber reaches higher temperature internally than externally depends on its moiscure content (m. c.) and thickness. If the lumber is thick and contains more m. c. , the rate is slow and fast reversely. The rate also varies with lumber's internal structure, the dense wood is slow, and the loose one fast. The temperature between the internal and external wood is different based on the m. c. and thickness of lumber. The thinner the lumber and lower the m. c. , the smaller the temperature difference. Temperature of wet ball is more important in drying.To dry the medium-thick block the temperature is 50-65℃; to thick block, 60-75℃; and to very large square lumber, 70-85℃.