RFV Drying Schedule Development for Thick Western Red Cedar Timbers

Abstract Radio frequency vacuum drying of timbers could result in internal checking (honeycombing) due to elevated internal temperatures and pressures that is believed to be associated to the level of applied power density, but it might be also related to the way electric power is applied during the drying process. In this exploratory study the relationship between power density and wood damage for thick western red cedar dried in a laboratory RFV dryer was evaluated. Two different types of drying strategies were assessed and the results were used to identify apparent trends and thus recommend the drying schedule that appears to minimize internal and surface checking.

[1]  Stavros Avramidis,et al.  Exploratory radio-frequency/vacuum drying of three B.C. coastal softwoods , 1992 .

[2]  Taras,et al.  Comparison of moisture content distribution, stress distribution and shrinkage of red oak lumber dried by a radio-frequency/vacuum drying process and a conventional kiln , 1984 .

[3]  Stavros Avramidis,et al.  Drying characteristics of hem-fir squares as affected by species and basic density presorting , 1996 .

[4]  Stavros Avramidis,et al.  Commercial-scale RF/V drying of softwood lumber. Part 2. Drying characteristics and lumber quality , 1996 .

[5]  Martin R. Okos,et al.  CLASSIFICATION OF DRYING MODELS FOR POROUS SOLIDS , 1993 .

[6]  S. Avramidis,et al.  Drying Characteristics of Thick Lumber in a Laboratory Radio-Frequeocy/Vacuum Dryer , 1994 .

[7]  John F. Siau,et al.  Wood--influence of moisture on physical properties , 1995 .

[8]  S. Avramidis.  Radio-frequency/vacuum drying of softwood : drying of thick western red cedar with constant electrode voltage , 1994 .

[9]  Patrick Perré,et al.  Physical Formulation and Numerical Modeling of High Frequency Heating of Wood , 2003 .

[10]  S. Avramidis,et al.  Predicting Thermal Efficiency in Timber Radio Frequency Vacuum Drying , 2004 .

[11]  Stavros Avramidis,et al.  RADIO FREQUENCY VACUUM DRYING OF WOOD. I. MATHEMATICAL MODEL , 2001 .

[12]  K. Luyben,et al.  Drying of food materials: a review of recent developments , 1978 .

[13]  P. Perré.  Measurements of softwoods' permeability to air: Importance upon the drying model , 1987 .

[14]  R. M. Perkin,et al.  The heat and mass transfer characteristics of boiling point drying using radio frequency and microwave electromagnetic fields , 1980 .

[15]  S. Avramidis,et al.  Drying thick western hemlock in a laboratory radio-frequency/vacuum dryer with constant and variable electrode voltage , 1994 .

[16]  Stavros Avramidis,et al.  Commercial-scale RF/V drying of softwood lumber. Part 3. Energy consumption and economics , 1997 .

[17]  S. Avramidis,et al.  Moisture flow characteristics during radio frequency vacuum drying of thick lumber , 1997, Wood Science and Technology.

[18]  Patrick Perré,et al.  PROCESSES RELATED TO DRYING: PART I, THEORETICAL MODEL , 1991 .