微波乾燥測定木材含水率可行性之研究

Feasibility Study of Wood Moisture Content Determination Using Microwave Drying

熊如珍(Ju-Chen Hsiung) ； 翟思湧(Sy-Yung Jai)

《台灣林業科學》 12卷2期 (1997/06) Pp. 203-210

https://doi.org/10.7075/TJFS.199706.0203

摘要

本研究旨在探討微波乾燥測定木材含水率之可行性，特以檸檬桉(Eucalyptus citriodora)與香楠(Machilus zuihoensis)為試材，就微波烘箱照射與傳統烘箱乾燥，分別測計其生材含水率、氣乾材含水率以及纖維飽和點含水率。
試驗結果顯示：自生材或氣乾材乾燥至絕乾狀態，若經由傳統烘箱(103±2℃)乾燥，檸檬桉試材需要長達3天的時間，香楠試材則需24小時；若改採微波烘箱照射時，檸檬桉試材僅需2（氣乾材）或4分鐘（生材），香楠試材亦僅90秒鐘（氣乾材）或3分鐘（生材）。香楠心材纖維飽和點含水率之測定，經由收縮率所推算者（傳統烘箱者28.36%，微波烘箱照射者28.95%，費時2週以上），與依據微波烘箱照射之乾燥速率所推定者（28.60%，費時60秒鐘），二處理間之結果一致，並無差異。

關鍵字

微波乾燥 ； 烘箱乾燥 ； 木材含水率 ； 檸檬桉 ； 香楠

並列摘要

This study evaluates the feasibility of wood moisture content determination using microwave drying instead of conventional oven drying. Lemon-scented gum (Eucalyptus citriodora) and incense machilus (Machilus zuihoensis) were used for this study.
Treatments of wood drying were: A (conventional oven drying) and B (Microwave oven drying). The moisture contents of green and air-dried specimens were tested for lemon-scented gum and incense machilus. The moisture content at the fiber saturation point was tested only for incense machilus.
The results of this study indicate that:
1. The times of the wood moisture content determination using microwave drying (treatment B) for lemon-scented gum were 2 min (air-dried wood) or 4 min (green wood), and for incense machilus were 1.5 min (air-dried wood) or 3 min (green wood).
2. For incense machilus, the differences of the moisture contents at the fiber saturation point (calculated from the shrinkage) were not significant between treatments A and B.
3. For incense machilus heartwood, the time (determined for the moisture content at the fiber saturation point) obtained from the drying rate for treatment B was a few minutes, white that for the shrinkage for treatment A was more than 2 weeks.
4. The application of microwave drying reduces the drying time for wood moisture content determination as compared with using conventional oven drying.

並列關鍵字

microwave drying ； oven drying ； wood moisture content ； lemon-scented gum ； incense machilus