Study On Drying Technology Of Small-diameter Manchurian Ash, Mongolian Oak And Birch

In this paper, the intermittent-heating and consecution-heats tests had been carried through to dry small-diameter lumber of northeast Mongolian Oak, Manchurian Ash and Birch by automatic conventional drying kiln with top-fan. The development and change law of MC , shrinkage and wood surface drying stress had been discussed. The factors affected dry quantity of small-diameter lumber had been analyzed. The final drying schedules are developed according to the result of the research, and the available drying technology of small-diameter lumber had been analyzed. Some advices are given to improve drying quality.The result of research show that: the drying rate of small-diameter lumber is fast than mature wood, and the time of beginning of shrinkage is more early; The intermittent heating makes the biggest value of stress backward and relax the drying stress, the more long result in intermittent time, impression is more obvious, especially Mongolian Oak and Manchurian Ash.The heart wood takes place longitudinal crack most easily; The bend emerge easily among un-standard flat or felt type of lumbers; The influence of heating method, lumber size, position of lumbers in top and bottom of the kiln to small-diameter lumber are bent and distortion.It is available to dry small-diameter lumber with small size, through by automatic conventional drying kiln with top-fan, and the intermittent-heating. The final drying schedules are developed according to the result of the research; Some advices are given to improve drying quality, such as preliminarily picking up, before drying, mildschedule, etc.After drying, the quantity of small-diameter lumber of Mongolian Oak and Manchurian Ash with intermittent-heating about 2 hours and consecution-heats tests have got to GB' 3; With intermittent-heating about 6 hours, the quantity of small-diameter lumber of Mongolian Oak and Manchurian Ash reach GB'2; All of the quantity of small-diameter lumber of Birch with intermittent-heating and consecution-heats tests have got to GB'3.The available drying technology of small-diameter lumber had been analyzed, the final drying schedules are developed according to the result of the research, and some advices are given to improve drying quality. This article prove a way preliminarily for drying , develop and use small diameter wood .