Characteristics of vacuum wood drying kiln

Compared with the conventional drying, vacuum wood drying kiln can be achieved under the condition of low temperature rapid drying of wood, and ensure the quality of wood drying, largely avoid the generation of wood shrinkage defects.Through expert analysis to explore the discovery, cypress, for example, above the fiber saturation point, vacuum drying rate for conventional dry 2.34 ~ 2.88 times;While in the FSP, is 2.90 ~ 4.14 times.
Vacuum condition is the movement of the internal moisture can speed up the wood, wood drying speed, but may be more to speed up the wood surface water evaporation, the wood moisture content and high vacuum degree of improper or absolute pressure, moisture content of timber reach to the gradient will significantly increase, which can cause internal stress of wood increases, resulting in the possibility of deformation and cracking will also increase, causing the expansion of wood drying defects, so to grasp is the core part of vacuum conditions.Practice proved wood intermission vacuum drying convection heating drying cycle compared with the conventional kiln dry process, was only about a third, and the investment cost and conventional kiln drying equipment investment, and high vacuum drying quality.Vacuum drying quality advantage is reflected in: some pith of oak wood, northeast China ash timber, with conventional drying is very difficult to guarantee quality, drying with intermittent vacuum drying method basically didn’t produce the defects such as warping and cracking;Some kiln drying defects more difficult after dry wood vacuum drying method is used to dry, dry fall rate have significantly decreased.