Journal of the Korean Wood Science and Technology
- Volume 22 Issue 1
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- Pages.66-71
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- 1994
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- 1017-0715(pISSN)
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- 2233-7180(eISSN)
Shrinkages of Prefrozen or Presteamed Wood
전처리(前處理) 목재(木材)의 수축율(收縮率) 변화(變化)
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Kang, Ho-Yang
(College of Agriculture, Chungnam National University)
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강호양
(충남대학교 농과대학)
- Received : 1994.02.14
- Published : 1994.03.30
Abstract
To increase drying rate and reduce drying degradation, pretreatments such as prefreezing and presteaming have been widely used in wood industries. Presteaming lumbers prior to kiln drying is known positively to improve its permeability, to increase diffusion coefficient and to reduce discoloration, but negatively to increase collapse. Prefreezing lumbers prior to kiln drying is also known to reduce significantly its drying defects and its shrinkages. Thus it is no doubt that the pretreated lumbers shrink diversely from the untreated. In this study the shrinkage behaviors of the pretreated specimens are investigated by drying two tropical hardwoods (Apitong and Taun) in three different dying conditions: high temperature and slow drying rate (drying in a closed cylinder), high temperature and rapid drying rate (drying in an oven) and low temperature and slow drying rate(drying at room temperature). The prefrozen specimens show the least volumetric shrinkages in most drying conditions. The specimens dried in cylinders shrink most among all drying conditions. In general the pretreated specimens reached the 30 % moisture content faster than the untreated by about 30 %.