Abstract:

A series of radio frequency/vacuum (RF/V) drying tests were conducted on boxed-heart square timber of plantation larch with cross section of 100 mm×100 mm. Drying processes under various RF/V conditions were analyzed in terms of drying quality and drying rate. Kerfing and superheated-steam pretreatment were introduced during the process in order to minimize the surface checks. High drying quality has been achieved with optimizing the drying conditions. The run-through kerf and superheated-steam pretreatment at the temperature of 105 ℃ could significantly reduce the surface check occurred during the drying.

Key words: radio frequency/vacuum (RF/V) drying, plantation larch, boxed-heart square timber, kerf pretreatment, superheated-steam pretreatment