Apparatus for viscoelastic thermal compression of wood

Abstract

Viscoelastic Thermal Compression (VTC) of wood is a treatment which greatly improves material properties by means of densification with mechanical compression perpendicular to the grain. VTC is similar to other wood densification processes, but is designed for thin lamina and employs dynamic temperature and steam pressure conditions. A device was constructed that is capable of producing VTC wood. Details of the construction and operation of the VTC device are presented. The device consists of a pressurized chamber with variable volume. Wood density may be modified from the initial density of the virgin wood up to approximately 1400 kg/m3. Control of steam pressure and temperature insures that the wood cell walls are not fractured during the process. The device is designed for batch operation and may be adapted to a conventional laboratory hot-press. An example operating schedule is described, but other procedures are possible within the design parameters of the device.