Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
권호 표지

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

산업용 규모의 압체고주파진공건조시스템 성능 평가

  • 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)
  • 이남호 (전북대학교 농업생명과학대학(농업과학기술연구소)) ;
  • ;
  • 황의도 (전북대학교 농업생명과학대학(농업과학기술연구소)) ;
  • 장세환 (전북대학교 농업생명과학대학(농업과학기술연구소)) ;
  • 신익현 (전북대학교 농업생명과학대학(농업과학기술연구소))
  • Received : 2008.12.11
  • Accepted : 2008.12.24
  • Published : 2009.05.25
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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.

본 연구에서는 수용재적 약 $3m^3$ 크기의 압체고주파진공건조시스템을 이용하여 Azobe (Lophira alata)와 국산 소나무(Pinus densiflora) 제재목을 건조하면서 건조시스템의 성능을 평가하였다. 압체고주파진공건조기의 진공도는 80~105 mbar를 유지시켰고, 건조 중 재온은 건조초기 $40^{\circ}C$에서 시작하여 건조말기 $60^{\circ}C$까지 상승시켰다. 全건조기간에 걸쳐 기전전극판측의 재온은 제어온도보다 항상 높게 유지되는 반면, 접지전극판측의 재온은 항상 낮게 유지되었다. 건조시간이 경과함에 따라 접지전극판측의 재온은 제어온도보다 더욱 낮고 기전전극판측의 재온은 제어온도보다 더욱 높게 나타났다. Azobe의 경우 입력포트측의 평균최종함수율보다 입력포트반대측의 평균최종함수율이 모든 잔적층에서 미미하게 높게 나타났으며, 잔적층의 수직방향으로의 최종함수율은 기전전극판측에서 접지전극판측을 향할수록 높게 나타났다. 기전전극판과 인접한 잔적층의 경우 재목당 평균할렬의 발생길이가 매우 경미하였으나, 접지전극판측을 향할수록 증가하는 경향을 보였다. 또한 투입된 에너지의 효율면에 있어 선진국의 상용설비와 유사한 수준을 보여 주는 것으로 평가되었다.

Keywords

Acknowledgement

Supported by : 농림부

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