Discoloration of beech wood during drying

Veliko krčenje bukovine je pogost vzrok nastalim razpokam in razvrednotenju lesa v postopku sušenja. Vse pogosteje se pojavlja nezaželeno obarvanje lesa. V realnih industrijskih pogojih smo na 7 šaržah preverili vpliv modificiranih sušilnih programov in tehnologije na kakovost osušenega lesa z vidika mehanskih poškodb in obarvanja. Prisotnost mehanskih sušilnih napak je bila v povprečju vseh šarž približno 7 %, kar je primerljivo s sušenjem s standardimi programiobarvanje pa se je zmanjšalo v povprečju iz 20 % na 5 %. Najboljše rezultate smo dosegli s hitrim sušenjem svežega lesa pri nizkih temperaturah. Na hitrost in enakomernost sušenja smo vplivali tudi s pravilno pripravo zložajev in ustreznim polnjenjem sušilnih komor. Elementi so se sušili hitreje, manj obarvali in razpokali. S povečanjem površine izhlapevanja na žaganih elementih smo dosegli do 40 % višje sušilne hitrosti ob primerjavi kakovosti sušenja.Great shrinking of beech wood often causes ruptures, and therefore wood devaluation during the process of drying. Uneven discolorations of the wood appear often. On 7 loads, the influence of modified kiln schedules, and technology impact on dried wood quality, regarding mechanical damages and discoloration, were studied in real industrial conditions. The presence of mechanical drying defects of all the loads on average was about 7%, comparable to the drying using standard programmesdiscoloration on average diminished from 20 % to 5 %. The best results were acquired by quick drying of moist wood at low temperatures. The correct stickering and adequate kiln loading have their impact on duration and more stable drying. Wood elements dried more quickly, there was less discoloration and less ruptures. By increasing the evaporation surface of sawn elements for up to 40 % the drying rate were acquired at suitable drying quality