Effect of surface roughness on drying speed of drying lamellas in veneer roller dryer

Abstract

Lamellas, which are defined as top layers of multilayer parquet and favourable to wood veneer can be dried in jet ventilated automatic veneer roller dryer due to short drying period. The objective of this study is to determine the effect of surface roughness on the drying speed of the veneer roller dryer. Quercus spp., frequently used tree specie in Turkish solid wood and multilayer parquet industries was chosen as material in this study. Pre-dried lamella blocks were cut into 4 different machines. As a
result, 4 test groups of lamellas displaying different surface roughness values were obtained. Lamellas which belong to each of these 4 test groups were also divided into 2 sub-groups and dried at 90 and 130°C drying temperatures. Drying was evaluated in relation to drying speed. Mitutoyo SJ 301 profilmeter was used for determining surface roughness values. Drying speed of lamellas was expressed as: dividing difference of initial moisture content and final moisture content values to drying
time value. The result of variance analyses showed differences between groups as surface roughness values. There was no difference between groups as drying speed were determined at 90 and 130°C temperatures. Furthermore, the relation between surface roughness values and drying speed was searched using correlation analysis and no significant relationship was found. Finally, it was determined that there was no effect of surface roughness on drying speed in radial cut, pre-dried lamellas, which have surface roughness values between 10.464 and 15.064 ìm, drying in jet ventilated roller dryer, at 90 and 130°C temperatures.