Effect of pretreatment with high temperature and low humidity on drying time and prevention of checking during radio-frequency/vacuum drying of Japanese cedar [Cryptomeria japonica] pillar
2010
Lee, N.H., Chonbuk National Univ., Chonju (Korea R.) | Li, C. | Zhao, X.F. | Park, M.J.
This study investigated the effect of pretreatment with high temperature and low humidity (HT-LH) on characteristics of radio-frequency/vacuum (RF/V) drying of boxed heart timber of Japanese cedar (150 x 150 mm in cross section, 3600 mm long). From green to approximately 15% moisture content, the drying times including HT-LH treatment were 170 h for the nonkerfed control, 190 h for the kerfed control, and 150 h for both the kerfed and nonkerfed HT-LH specimens. Surface checks were effectively prevented by the HT-LH treatment while the kerfed HT-LH specimens were free from surface checks. In order to prevent the formation of internal checking during RF/V drying, it is suggested that HT-LH treatment should finish around the fiber saturation point.
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