Drying and gas or vapor contact with solids – Material treated by electromagnetic energy – Infrared energy
Patent
1996-10-02
1998-10-06
Joyce, Harold
Drying and gas or vapor contact with solids
Material treated by electromagnetic energy
Infrared energy
34396, 34417, 34443, 34479, 34539, 34212, 34225, F26B 334
Patent
active
058159452
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to wood having its pit membranes between cells constituting the wood broken for enabling wood drying to be effectively carried out.
BACKGROUND ART
The present inventor has already proposed a technique intended to greatly reduce a cost in wood drying by removing growth stress in wood (Japanese Patent Application No.308723/1993).
Wood from a naturally grown tree is, in itself, indispensable to human life from ancient times as a material for houses or furniture. To utilize wood as a material for houses or furniture, however, wood must be sufficiently dried and then subjected to work.
This is because wood immediately after felling contains large amount of water, wood undergoes contraction or expansion with time depending upon amount of water content, thereby leading to imbalances in shape or dimension. Further, physical and chemical properties of wood varies depending upon change in water content. Accordingly, to reduce water content, wood has heretofore been dried sufficiently over a long period of time to such an extent that the wood would undergo .no substantial deformation, and then subjected to work.
Wood drying includes natural drying carried out over a period of several tens years and artificial drying effected by forcing water contained in wood as described above to evaporate under a hot air stream. In particular, artificial drying is expensive and thus employs various techniques under-the existing circumstances.
However, such wood drying heretofore carried out is intended to remove water contained cells constituting wood naturally over a long period of time or forcibly by adding various steps such as heating, when considered at level of cells constituting wood.
However, wood is vital before felling, and thus, it is said that even if some branches and the like are damaged, self-remedy activity spontaneously functions for closing pits present between cells constituting wood, in particular, cells constituting tracheids and vessels which lead to the damaged branches to prevent contained water from escaping.
In other words, nutrients and water are essential for growth of tree, and wood absorbs nutrients and water from its roots and transfer the nutrients and water to its trunk, branches and leaves through pipes composed of cells referred to as tracheids or vessels. Individual cells constituting wood deliver or receive the nutrient and water between the cells by themselves or through the tracheids or vessels. Accordingly, a large number of small apertures or depressions referred to as pits (formerly explained as Mon-Koh) are present in cell membranes between the cells.
The pits are present generally in the form of a pair between two cells as described below, and therefore, often referred to as pit-pair. The basic structure is as schematically shown in FIG. 1. FIG. 1(a) is a schematic view showing basic structure of a section of a pit membrane, and FIG. 1(b) is a schematic plan view of the pit membrane, wherein character 1 represents torus, 2 a margo, and 3.sub.1 and 3.sub.2 pits. Cells of a tree having pits of such a basic structure are so constructed that, for growth of the tree, a gap is provided between the torus 1 and one pit 3.sub.1 or the other pit 3.sub.2 of the pit-pair to intercellularly supply nutrients and water essential for growth of the tree.
In other words, between such a pit-pair a membrane referred to as pit membrane is present, and the membrane comprises a torus (T) and a margo (M). These constitute such a mechanism that if some of cells constituting wood are once broken by, for example, felling of tree, pits in cell membranes are closed by self-remedy activity of the cells per se constituting the wood to prevent water contained in the cells from escaping.
To prevent evaporation of the water contained in the cell constituting the wood, the one pit 3 1 or the other pit 3.sub.2 of the pit-pair is blocked with the torus 1 (see FIGS. 1(c) and 1(d)) to prevent moisture gradient. Electron micrographs of pits between cells are shown in FIGS.2(1) a
REFERENCES:
patent: 1413018 (1922-04-01), Fujino
patent: 4179820 (1979-12-01), Steffensen et al.
patent: 5293700 (1994-03-01), Ishii
patent: 5472720 (1995-12-01), Rakhimov et al.
Membrane Structure of Bordered Pit on the Tangential Wall of Tracheid in Coniferae Species, Seizo Fujikawa et al. Mokuzai Gakkaishi vol. 20 No. 3 pp. 103-110 1974.
IAWA Bulletin vol. 8(3) pp. 237-244, 1987.
Notes on Torus Development in the Wood of Osmanthus Americanus, Roland R. Dute et al. IAWA Bulletin vol. 9(1) pp. 41-51, 1988.
Chuou Mokuzai Kaihatsu Kabusiki Kaisha
Gravini Steve
Joyce Harold
Minoru Ando
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