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Performance of a Commercial Scale Radio-frequency/vacuum Dryer Combined with a Mechanical Compressive Load  

LEE, Nam-Ho (College of Agriculture & Life Sciences(Institute of Agricultural Science & Technology), Chonbuk National University)
ZHAO, Xue-Feng (College of Agriculture & Life Sciences(Institute of Agricultural Science & Technology), Chonbuk National University)
HWANG, Ui-Do (College of Agriculture & Life Sciences(Institute of Agricultural Science & Technology), Chonbuk National University)
CHANG, Sae-Hwan (College of Agriculture & Life Sciences(Institute of Agricultural Science & Technology), Chonbuk National University)
SHIN, Ik-Hyun (College of Agriculture & Life Sciences(Institute of Agricultural Science & Technology), Chonbuk National University)
Publication Information
Journal of the Korean Wood Science and Technology / v.37, no.3, 2009 , pp. 192-199 More about this Journal
Abstract
This study was carried out to investigate the performance of a radio-frequency/vacuum dryer combined with a mechanical compressive load (RF/VC) with a scale of about $3m^3$ during drying board of Azobe (Lophira alata) and Korean red pine (Pinus densiflora). The degree of vacuum of the RF/VC system was maintained at 80~105 torr, and wood temperature was increased from $40^{\circ}C$ at the beginning of drying to $60^{\circ}C$ at the end of drying and the radiofrequency generator was operated with schedule of 7 minute-ON and 3 minute-OFF. The wood temperatures near charge plate always remained higher than those of the control during all of the drying stage, whereas the wood temperature near ground plate always remained lower than those of the controlled. As drying time proceeding, the temperature of the wood near ground plate presented lower than those of the control. Whereas the temperature of the wood near charge plate presented higher than those of the controlled. The final average moisture contents of the Azobe boards stacked near the input side of the RF generator showed slightly lower than those near the opposite side. Those of the wood stacked in the layers near the charge plate were lower than those of near the ground plate. The average length of surface checks of the Azobe boards stacked near the charge plate was very slight, whereas that toward the ground plate represented high values. The efficiency of input energy was simliar with the commercial systems.
Keywords
radio-frequency/vacuum drying combined with a mechanical compressive load (RF/VC); Azobe; Korean red pine; wood temperature; final moisture content; checks; efficiency of input energy;
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