Application Research Of Wood Roller-pressure Process

Roller- compression process is a new sort of wood protection process with very good development prospect,which can process the wet materials or raw materials directly,leave out the pre-drying process,decrease energy consumption,shorten processing time.In this study a novel impregnation technique called roller- compression is employed and White pine is used as experimental timber.Board with water saturation is compressed transversely by rollers in the preservative liquid,and which is absorbed when it leaves from the rollers.The compressibility and its ratio are studied and analyzed systematacially in the paper to discuss the physics mechanics performance and its effect of impregnation grocess.Under room temperature,experimental board with water saturation is copressed in tangential and radial direction and a few compression rates without limit in cross direction.The parameter variance rate is showed through percent rate of the difference value after and before roller-compression treatment divided by before.As results,the followings could be obtained:1) By testing and analysis of mechanics properties of wood compressed by roller,it appears that oven-dry density,air-dry density and basic density of wood increase.2) The coefficients of shrinkage of air-dry and oven-dry of radial direction,tangential direction and cubage enlarge gradually along with the rise of the compression ratio,the coefficients of shrinkage of tangential compression enlarge more than that of radial compression.The dimensional stability of treated wood reduces a little.3) The mechanics strength of wood compressed reduced differently.The loss of mechanics strength is cute as the increase of the compression ratio.4) The technics parameter of immersed deepness is discussed.It can improve obviously osmosis of wood by adding steeping time and times of compression,the impregnation depth parallel to compression direction is more than perpendicular and it increases slowly along with the rise of the compressibility rate because of the impregnation time and times of compression.5) X-ray diffractometer are used in this study.The 2θ- Diffraction curves between the compressed wood and uncompressed wood are homology.The relative crystallinity of wood compressed decrease a little.6) As the microcosmic analytic of cell wall from the roller-compression show,the cranny in pits membranes of intervascular appears because of squeezing;the cell wall is destroyed severity because of more than 30%of the compression ratio.