Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Defibration by projection or explosion
Reexamination Certificate
2001-09-24
2002-10-08
Yao, Sam Chuan (Department: 1733)
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Defibration by projection or explosion
C241S001000, C241S002000
Reexamination Certificate
active
06461472
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention generally relates to a technology for effective use of wooden source materials, and more particularly to a technology for decomposing into fragments various things, such as excessively slim trees and branches normally left as residues in forests, flitches and wood cuttings produced in factories, construction and demolition wastes as one of industrial wastes, and so forth, by water-vapor explosion, and a technology for binding these fragments by any appropriate adhesive and shaping them into a new wooden material.
Wood has been used widely since old days because of a number of advantages it has, such as giving soft and warm impressions, being easy to obtain and work, and being reproducible. Moreover, along with the global increase of population and improvements of human lives, the amount of use of wood has increased remarkably, and the demand for wooden materials is getting higher and higher, and more and more diversified.
Under these circumstances, there have been developed new wooden materials like OSB (orientated strand boards), WB (wafer boards), PSL (parallel strand laminates) in addition to conventional lumbers, bonded wood, plywood laminates, LVL (veneer laminates), shavings boards, fiberboards, wood wool cement boards and wood piece cement boards.
However, only with developments of these conventional wooden materials, limited forest resources cannot be used effectively.
For example, conventional lumbers and bonded wood use only a half of the entire volume of trees, and a lot of flitches and wood cuttings have been left useless.
In case of plywood laminates, LVL and PSL, 50 to 70% in volume of logs can be used, but the logs are limited to those with large diameters.
As to shavings boards, fiberboards, OSB and WB, logs of relatively small diameters can be used as well, and a high yield is promised. However, those with very small diameters, such as forest residues, and those containing metal pieces, earth, sand or other foreign matters, such as construction wastes, still remain unused. In case of wood wool cement boards and wood piece cement boards, their strength performances are not large enough to be used as structural members.
Toward an effective use of residues and wastes, there have been developed techniques for crushing them into chips, digesting and splitting them into the form of pulp, and manufacturing paper and boards therefrom.
As one of these techniques, there has been proposed a method of making fibrous elements by first blowing high-temperature, high-pressurized steam onto chips in a pressure tube and then momentarily releasing the pressure, in the process of the digestion (explosive crushing method). However, it needs the process of once chipping residues and wastes, and has not yet overcome technical problems difficult to control, such as injection of high-temperature, high-pressurized steam.
As explained above, although various efforts have been made toward effective use of wood resources, to date, the purpose has not been achieved sufficiently.
For example, almost all of very thin trees and branches are left unused in forests.
Further, although flitches, wood cuttings and other fragments produced in the wood industry are being crushed into chips for use as source material of paper and boards, or sent to wood-waste boilers as a fuel, these ways of use are not sufficiently effective from the economical viewpoint. Regarding construction wastes and other industrial wastes, although a part thereof is crushed into chips, major part thereof is still being discarded or incinerated because it is difficult to collect them or re-use them due to the presence of metal pieces, earth, sand or other foreign matters therein.
Taking account of the today's tendency toward a decrease of the forest resources along with developments and aggravation of the environments for the worse thereby, it is an urgent issue from the technical and economical viewpoints to find out how to deal with and use these thin trees, branches, cutting wastage from factories, industrial waste, and so on, heretofore not used effectively by any existing means.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide fragments obtained by water-vapor explosion of wooden raw materials, wooden material containing such fragments as its aggregate, their manufacturing methods and machines, which ensure the effective use of lumber resources.
According to the invention, there is provided a technique for reforming wood, bamboo and other wooden materials into fragments having desired properties and various sizes and shapes so as to enable fabrication of wooden material fragments usable various purposes even from slim trees, branches, wood cuttings from factories, construction wastes, and so on, to thereby overcome the problems involved in conventional techniques, comprising the steps of:
(a) adjusting water content of wooden source materials including wood and bamboo;
(b) compressing the source materials under a high temperature; and
(c) after compressing the source materials for a predetermined duration of time, instantaneously releasing the pressure to invite water vapor explosion in the wooden materials and partly or entirely releasing fiber coupling in the wooden materials along fibers thereof.
In the step (b), a plurality of source materials may be stacked to align their fibers substantially in parallel and may be compressed under a high temperature.
According to the invention, there is further provided a technique comprising the steps of:
(a) adjusting water content of wooden source materials including wood and bamboo;
(b) compressing the source materials under a high temperature; and
(c) after compressing the source materials for a predetermined duration of time, instantaneously releasing the pressure to invite water vapor explosion in the wooden materials and partly or entirely releasing fiber coupling in said wooden materials along fibers thereof, thereby to obtain the explosive-split fragments;
(d) drying the explosive-split fragments;
(e) applying an adhesive onto the dried explosive-split fragments;
(f) stacking the explosive-split fragment obtained in the step (e); and
(g) compressing the stacked explosive-split fragments under a heat to obtain a multi-layered material of explosive-split fragments of a predetermined size and shape, to thereby realize new and useful wooden materials to overcome the problems involved in the conventional techniques.
According to the invention, there is further provided a method for manufacturing a cement board of explosive-split fragments obtained by introducing explosive-split fragments obtained from wooden materials through predetermined steps into a frame, then supplying mortar onto the from wooden materials, next vibrating the frame to remove voids in the mixture of the explosive-split fragments and mortar, compressing and fixing the mixture, releasing the pressure after hardening the mortar, and curing a mass of explosive-split fragments hardened and shaped into a predetermined configuration by mortar, the predetermined steps comprising:
(a) adjusting water content of wooden source materials including wood and bamboo;
(b) compressing the source materials under a high temperature; and
(c) after compressing the source materials for a predetermined duration of time, instantaneously releasing the pressure to invite water vapor explosion in the wooden materials and partly or entirely releasing fiber coupling in the wooden materials along fibers thereof, to thereby realize new and useful wooden materials utilizing wooden materials to overcome the problems involved in the conventional techniques.
According to the invention, there is further provided a technique including predetermined steps to thereby realize new and useful wooden materials to overcome the problems involved in the conventional techniques, the predetermined steps comprising:
(a) adjusting water content of wooden source materials including wood and bamboo;
(b) compressing the source materials under a high temperature;
(c) after compress
Lipsitz Barry R.
McAllister Douglas M.
The Forestry and Forest Products Research Institute
Yao Sam Chuan
LandOfFree
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