科研之友
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摘要
New Zealand%26apos;s indigenous red beech timber is commonly air dried to remove much of the moisture before it is dried in a dehumidifier to the desired final moisture content. Air drying times are affected significantly by both the season the timber is stacked and year-to-year climate variations. This paper investigates drying-time variations at different locations in New Zealand to represent the variety of climatic conditions possible (from dry to wet), using a validated drying model and published climate data spanning a decade. In addition, an alternative method of drying red beech timber known as warehouse pre-drying is investigated. This method employs a relatively inexpensive drying chamber operated at low temperatures and humidities to dry red beech in a controlled fashion. The simulations show that 27 mm red beech timber stacked in spring can air dry nearly twice as quickly as the same timber stacked in autumn. Year-to-year climate variations can change the air drying time by over 2 months, which demonstrates the importance of tracking moisture content to ensure the timber is dried to the desired level. Warehouse pre-drying can be used to dry red beech from the green condition more quickly than can be achieved by air drying and with relatively low energy requirements compared with more the traditional methods of drying such as dehumidifier or conventional-kiln drying. The problem of significant green moisture-content variations in red beech timber can be addressed by pre-sorting the green timber or kiln equalising the air-dried or warehouse pre-dried timber.
- 出版日期2012-8
