Effect of pretreatment with high temperature and low humidity on drying time and prevention of checking during radio-frequency/vacuum drying of Japanese cedar pillar

• Published in: Journal of wood science Vol. 56; no. 1; pp. 19 - 24
• Main Authors: Lee, Nam-Ho, Li, Chengyuan, Zhao, Xue-Feng, Park, Moon-Jae
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.02.2010; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Cedar; Characterization and Evaluation of Materials; Drying; High temperature; Humidity; Life Sciences; Materials Science; Moisture content; Original Article; Pretreatment; Radio frequency; Wood Science & Technology; Compressive loading; High-temperature with low humidity; Radio-frequency/vacuum drying; Surface and internal check
• ISSN: 1435-0211; 1611-4663
• DOI: 10.1007/s10086-009-1050-4

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 × 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.