EP0496885A1 - Procede de modification du traitement du bois et analogue - Google Patents

Procede de modification du traitement du bois et analogue Download PDF

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Publication number
EP0496885A1
EP0496885A1 EP90914969A EP90914969A EP0496885A1 EP 0496885 A1 EP0496885 A1 EP 0496885A1 EP 90914969 A EP90914969 A EP 90914969A EP 90914969 A EP90914969 A EP 90914969A EP 0496885 A1 EP0496885 A1 EP 0496885A1
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EP
European Patent Office
Prior art keywords
timber
treatment
cracking
high temperature
wood product
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90914969A
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German (de)
English (en)
Other versions
EP0496885A4 (en
Inventor
Hideaki Takahashi
Kinji Tamakawa
Kiyoshi Sato
Isao Suzuki
Satoshi Yunome
Katsumi Honma
Yasuo Suzuki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KYOGYOKUMIAI SENDAI FANICHIA
MIYAGIKEN
Original Assignee
KYOGYOKUMIAI SENDAI FANICHIA
MIYAGIKEN
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Publication of EP0496885A1 publication Critical patent/EP0496885A1/fr
Publication of EP0496885A4 publication Critical patent/EP0496885A4/en
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/34—Organic impregnating agents
    • B27K3/36—Aliphatic compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/04—Combined bleaching or impregnating and drying of wood
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/06—Controlling, e.g. regulating, parameters of gas supply

Definitions

  • This invention relates to a method of treatment for modifying the characteristics of timber and other wood products, wherein, in applying heat treatment to various worked vegetable materials such as logs, worked timber or bamboo material, etc. (hereinafter referred to as "timber and other wood products” or “timber and the like” depending upon circumstances), while making use of characteristics that the timber and the like naturally have to manufacture worked vegetable materials to which various characteristics are added, this method is adapted to have the ability to prevent cracking in timber and the like subjected to heat treatment, and to improve workability of timber and the like which has a tendency to be deteriorated by application of heat, thus to allow such timber and the like to be worked vegetable materials having a higher quality and more versatile properties as compared to the prior art.
  • the inventors of this application are developing to put into practice a new worked vegetable material using these technologies to apply heat treatment to timber and the like to make artificial lignite or fossil wood, artificial smoked bamboo or high temperature heat treated material.
  • Such high temperature heat treated materials so called new materials, are not only utilized as substitutes for natural lignite or fossil wood in short supply, but also are utilized for combining pieces having light and shading with each other to make up a beautiful wooden mosaic, or are utilized for furniture or facing material by making use of adhesiveness or machine workability which cannot be found in natural lignite or fossil material, and the property to give light and shading in color tone by a temperature difference.
  • these new materials are exhibiting usefulness or utility in various fields such as water related facing material such as bath tubs, lavatory or kitchen units, etc.
  • the inventors have taken hints from the above facts to conduct studies with a view to realizing prevention of cracking and improvement in workability of material in the high temperature heat treatment of timber and other wood products under more rigorous or severe conditions that of the drying treatment, thus to complete the invention of this application.
  • Moisture in timber includes ordinarily free water and combined or absorbed water. During drying, only free water is first dissipated and removed at the surface layer. As drying is developed, combined water will also be removed. In the case of the former movement of free water, capillary phenomenon is dominant. On the other hand, the latter movement of combined water is based on diffusion. In this way, free water and combined water at the surface layer of timber are removed, so the timber is dried. However, the inner layer still remains in a state having a high moisture percentage. Thus, the dry portion attempts to contract, whereas the moisture contained portion resists contraction.
  • Japanese Patent Publication No. 7317/808 Japanese Patent Publication No. 7317/808 to carry out prediction of a crack caused by drying of timber by using AE detection technology to control the ambient temperature and humidity of the timber, thus to prevent cracking.
  • a method is only described of predicting an initial crack in the drying treatment on the basis of the number of accumulated AE and the rate of occurrence of AE. Namely, even in the drying treatment, only prediction of an initial crack of drying in a temperature zone of 30 to 80°C is conducted, and consideration is not made in connection with cracking in the latter part of the drying treatment and/or cracking in high temperature heat treatment above 1000°C.
  • a procedure is disclosed to know the number of accumulated AE and the rate of occurrence of AE immediately before the timber is cracked to operate control equipment when the AE occurrence rate reaches a limit value to relax the drying condition, thus to prevent a crack.
  • the correlation between the number of accumulated AE or the rate of occurrence of AE and the occurrence of a crack is effective in the initial part of drying, but the correlation is not necessarily exhibited in the latter part of drying or high temperature heating.
  • a first object is to provide a new technology capable of efficiently manufacturing high temperature heat treated material of a high quality from an industrial point of view.
  • impregnating technology for timber is widely adopted.
  • any impregnant is used in advance with a view to preventing cracking in drying or heat treatment.
  • the inventors have found that when a specific organic solvent selected from various impregnants is impregnated into timer, etc., thereafter to apply heat treatment thereto, a chemical reaction takes place inside, whereby internal plasticization occurs so that thermal fluidity is rendered to the material.
  • thermal fluidity inside the timber may prevent cracking during heat treatment, thus to develop the invention of this application.
  • a specific organic solvent to implement impregnating treatment to cause hydrothermal chemical reactions the inside of the timber is plasticized.
  • a second object to prevent cracking by heat treatment, to greatly decrease the brittleness of wood caused by the high temperature heat treatment, thus to improve workability.
  • the invention of this application contemplates attaining, by combining the following technical means, the technical solution to prevent the occurrence of cracks during heat treatment and to prevent the lowering of workability as a result of the timber becoming brittle by thermal treatment, which are drawbacks of the method of modifying treatment of timber to implement high temperature heat treatment in the atmosphere of incombustible gas already known as previously described.
  • monitoring of the AE accumulated event number and the AE occurrence rate is made on line on the basis of the above AE signal to discriminate phases or stages of drying or heat treatment to analyze and study the meaning of an AE signal detected while making a comparison with a reference value empirically determined in advance to carry out predictive judgement of cracking in the course of treatment to control temperature and humidity on the basis of predicted information to effect a control to relax the atmospheric conditions so that no cracking takes place in timber, etc. It is further made clear that since cracking of timber, etc. is caused by movement of moisture caused by the drying treatment and the heat treatment, and the denaturation of material due to heat, if temperature and humidity are adjusted as a control factor, cracking can be sufficiently prevented.
  • First is to improve workability by preventing cracking by impregnation treatment with an organic agent, and by allowing the timber to be chemically modified.
  • Second is to detect an AE signal to predict cracking of the timber, etc., by the information processing thereof to carry out atmosphere control using, as a control factor, temperature and humidity on the basis of the predicted information, thus to prevent cracking.
  • Third is to carry out heat and drying treatment and high temperature heat treatment at normal pressure or high pressure while conducting atmosphere control to thereby improve the wood property characteristics and the functional characteristics.
  • this invention contemplates providing a new worked vegetable material in which timber, etc., is efficiently subjected to a modifying treatment so that it has a high quality.
  • the first invention for which the patent is sought to be granted resides in a method of first impregnating an organic impregnant, e.g., oxyether such as polyethylene glycol or methyl cellosolve, etc., polyatomic alcohol, phenol, natural rubber, synthetic rubber, or mixtures including them in combination, into various worked vegetable materials, etc., such as logs, worked timber, bamboo material (timber or any other wood product) to allow a hydrothermal chemical reaction (hydrolysis) to take place, thus to carry out the impregnating treatment.
  • an organic impregnant e.g., oxyether such as polyethylene glycol or methyl cellosolve, etc., polyatomic alcohol, phenol, natural rubber, synthetic rubber, or mixtures including them in combination
  • various worked vegetable materials etc., such as logs, worked timber, bamboo material (timber or any other wood product
  • Material which may be subjected to the treatment of this invention is not just timber, etc., but includes all worked vegetable materials such as logs, worked timber, bamboo material, etc. irrespective of the kind of vegetable.
  • a specific organic impregnant to be impregnated may employ an oxyether such as polyethylene glycol, or methyl cellosolve, etc., polyatomic alcohol such as 1, 4 butanediol, etc., phenol, a natural rubber, synthetic rubber, or mixtures including them in combination.
  • an oxyether such as polyethylene glycol, or methyl cellosolve, etc.
  • polyatomic alcohol such as 1, 4 butanediol, etc.
  • phenol 1, 4 butanediol, etc.
  • natural rubber a natural rubber, synthetic rubber, or mixtures including them in combination.
  • timber is comprised of cellulose of 40 to 50%, hemicellulose of 15 to 25%, lignin of 20 to 30%, and other sub-ingredients.
  • bundles of aggregate of cellulose molecular chains dodge meshes existing in the form of sponge, and hemicellulose are filled into a gap therebetween.
  • Combination of respective compositions is carried in a form as stated above.
  • bundles of aggregates of the cellulose molecular chains are regularly arranged to form crystals. Since these crystals are linear high molecular having a cubic arrangement of regularity and many hydroxyl groups, there is a state where regular hydrogen bonds of hydroxyl groups are apt to occur between adjacent molecules.
  • thermoplasticity results from hydrothermal chemical reaction.
  • an approach is employed to impregnate a specific organic impregnant in the timber to place it in high temperature water at more than 100°C to allow hydrothermal chemical reaction (hydrolysis) to take place to dissolve a portion of the cellulose or lignin, etc., in the wood to partially cleave several chemical bonds, to change esters in the resin to alcohol, or to implement halogen substitution of lignin aromatic nuclear to provide lignin chloride, etc., thus to provide the state where the woody part has thermal fluidity (thermal plasticity).
  • this treatment is not necessarily required as a pre-processing (hydrothermal chemical reaction), but may be carried out later in a manner doubling as a high temperature heat treatment.
  • the impregnation-treated timber, etc., after undergoing drying treatment is placed in an atmosphere of more than 90% incombustible gas, and an AE sensor is attached on the timber, etc.
  • incombustible gas refers to inert or inactive gas such as argon, krypton or helium, etc., or mixed gas including one or two kinds of ammonium, sulfur dioxide, carbon dioxide and nitrogen.
  • Attachment of the AE sensor is carried out through a wave guide by taking temperature and humidity into consideration.
  • the attachment position of the wave guide is the test specimen cross section.
  • AE signals sent from the sensor are sorted into each amplitude class.
  • AE event numbers for each class are represented as shown in Fig. 2.
  • AE signals are amplified at a pre-amplifier and then subjected to a threshold comparison with a net value by a cracking monitor (more than 1V at 80 dB). By amplifying the signals thus processed, the number of AE events is detected. Recording of such AE event data is shown in Fig. 3, and recording of an accumulated AE energy is shown in Fig. 4.
  • this invention is directed to a method of treatment for modifying timber, etc., which is adapted to apply temperature so that its gradient is not steep while controlling the atmosphere so that no cracking occurs in the timber, etc., by using temperature and humidity as a control factor on the basis of the above predicted information, thus to carry out a predetermined high temperature heat treatment.
  • the main cause of crack occurrence in high temperature heat treatment is not movement of moisture, but contraction or expansion through a sudden temperature change. Accordingly, while gently setting the temperature gradient when temperature is applied or lowered where a crack occurs meets with this purpose, since the limit value of the temperature gradient where a crack occurs varies depending upon the initial moisture percentage, the kind of wood, the plate thickness, and the device, etc., it is required to measure AE in advance under a predetermined condition to set, at all times, the accumulated AE energy increasing rate to less than a limit value (warning limit standard).
  • the strength is enhanced or increased with respect to impact, compression or bending by increasing lignin, and the tensile strength is weakened or decreased by reducing cellulose.
  • the crystals of cellulose have a high melting temperature, and are subjected to thermal decomposition before being placed in a thermal fluid state, no thermal fluid state is eventually provided (Fig. 13). Namely, this treatment is featured below.
  • high temperature heat treatment is further carried out under incombustible conditions, i.e., in an atmosphere of incombustible gas to completely remove moisture while retaining tissue of a regular cubic arrangement as it is, and to harden or cure the entirety by thermal denaturation of protein or other ingredients.
  • the wood property is cured or hardened by this treatment, resulting in excellent weather resistance or water proofing. On the other hand, the wood becomes brittle, disadvantageously lowering workability.
  • acetyl groups or nitro groups, etc. are substituted for hydroxyl groups of cellulose to change the cellulose to a derivative to weaken the degree of hydrogen bonding, thus allowing the woody part to have thermal fluidity (thermal plasticity).
  • This invention relaxes curing of wood property by this treatment to decrease brittleness, and to recall tenacity or toughness intrinsic to wood thus to improve workability such as cutting property, etc.
  • an approach is employed to impregnate an organic impregnant, e.g., an oxyethyl such as polyethylene glycol or methyl cellosolve, etc., polyatomic alcohol, phenol, natural rubber, synthetic rubber, or mixtures including them in combination into various worked vegetable materials such as logs, worked timber, or bamboo material, etc., to implement impregnating treatment to cause hydrothermal chemical reaction (hydrolysis).
  • an organic impregnant e.g., an oxyethyl such as polyethylene glycol or methyl cellosolve, etc., polyatomic alcohol, phenol, natural rubber, synthetic rubber, or mixtures including them in combination into various worked vegetable materials such as logs, worked timber, or bamboo material, etc.
  • an AE sensor is attached to the impregnation treated timber, etc. to detect, as a signal, an AE that the timber, etc., produces in accordance with a change of the woody structure to carry out information processing of that signal to detect a crack of the timber, etc., to conduct a heat treatment at a temperature less than 80°C at a normal pressure while carrying out an atmosphere control so that no cracking takes place in the timber, etc., on the basis of the predicted information, thus to implement a drying treatment.
  • signals sent from the sensor attached to the wood, etc. are amplified at a pre-amplifier, and signals below a set level are cut out at a cracking monitor After such signals are amplified, the number of AE events of a specific amplitude is detected. The AE event data of the specific amplitude is recorded (Fig. 14). When this is illustrated as an accumulated energy, Fig. 15 is produced. The procedure until now is the same as that in the case of AE in the high temperature heat treatment. When a large number of such events are collected to carry out a statistical processing, a standard AE pattern in a timber dry treatment process as shown in Fig. 16 can be provided.
  • the first stage (I) is the stage where vapour is infiltrated or penetrated into the central portion of timber, etc., and the temperature and the moisture percentage become uniform, whereby drying is gradually developed.
  • the moisture percentage at the time when the first and second stages are divided is 25%, and corresponds to a fibre (tissue) saturation point (about 30 to 25%). At a point above the fibre saturation point, moisture in a liquid state exists in timber. At this stage, since cracks occur easily, attention must be sufficiently drawn.
  • the second stage (II) is the stage where moisture absorbed in the form of combined water into the tissue cuts the bond, and begins vaporization. Accordingly, the energy required for reducing the moisture percentage becomes larger than that at the first stage. It is considered that the tensile strength of the wood suddenly increases at this stage, thus to have the ability to tolerate a drying condition more severe than that at the first stage. Accordingly, a drying condition more severe than that at the first stage can be applied. Namely, at the second stage, it is possible to apply a drying condition more severe than that of this experiment. Thus, the drying time can be shortened.
  • the boundary between the second and third stages corresponds to about 15% of the moisture percentage.
  • the state of the moisture percentage of about 15% is considered to an equilibrium moisture percentage, and corresponds to the air dry state.
  • the method of predicting a "crack" in the drying process comprises: discriminating at which drying stage a present stage is at while monitoring the AE occurrence rate and the number of accumulated events on line, comparing the discriminated state value with the standard AE occurrence circumstances empirically determined (AE occurrence rate and AE accumulated event number), and the crack warning reference value, thus to carry out predictive judgement of a crack in the process of treatment.
  • an approach is employed to control the temperature condition and the humidity condition by using, as a reference, an optimum control pattern at that stage empirically determined on the basis of the crack predicted information to effect a control to relax the atmospheric condition so that no cracking takes place, or to allow the temperature condition and the humidity condition to be severe so that there is no loss in the treatment efficiency.
  • cracking is predicted by analysis of AE signals to carry out drying treatment while conducting the atmospheric control by using the temperature and the humidity as a control factor to dry the wood so that the moisture percentage of the timber, etc., becomes equal to a value less than 10%.
  • the impregnation-treated dried timber, etc. is placed in an atmosphere of more than 90% incombustible gas to carry out high temperature heat treatment at more than 100°C.
  • timber, etc. is placed in such a high temperature state, since it would become carbonized, it is preferable to place it in an incombustible gas atmosphere.
  • an approach is employed to attach an AE sensor to the timber to detect, as a signal, AE that the timber, etc., produces in accordance with changes in the woody structure to carry out information processing of that signal to predict cracking of the timber, etc., to carry out high temperature heat treatment at more than 100°C under high pressure or normal pressure while conducting the atmosphere control so that no cracking takes place, by using temperature and humidity as a control factor on the basis of the predicted information.
  • the second invention is directed to a method of treatment for modifying wood, etc., in which the above-mentioned approach is adopted.
  • the method of predicting cracking in timber, etc., in this high temperature heat treatment is the same as that of the invention of claim 1.
  • occurrence of AE signals having an amplitude more than a predetermined width and a limit value of the temperature gradient where a crack occurs vary depending upon the initial moisture percentage, the kind of wood, the plate thickness, and the device, etc.
  • the invention of this application is directed to a method of first carrying out impregnating treatment, to predict cracking of the timber, etc., on the basis of AE signals to dry the timber while controlling the atmosphere so that no crack takes place by using temperature and humidity as a control factor on the basis of predicted information, to subsequently carry out the high temperature heat treatment in consistency.
  • Fig. 17 shows, in model form, a standard AE occurrence pattern of the modifying treatment of timber, etc., for carrying out in consistency such dry treatment and high temperature heat treatment.
  • the third invention to which the patent is sought to be granted is directed to a method of treatment for modifying timber characterized in that "the method of detecting an AE as a signal to carry out information processing of that signal to predict a crack of timber, etc., to control the atmosphere so that no crack takes place in the timber, etc., by using temperature and humidity as a control factor", which is described in the above-mentioned first and second invention is modified as follows.
  • an approach is employed to detect an AE as a signal to discriminate amplitude of those signals from the total count number of AE to recognize AE signals having an amplitude greater than a predetermined value as a dangerous signal for crack to further carry out monitoring of the number of accumulated AE events and AE occurrence rate to discriminate if the present stage is an initial, medium or later stage, or whether or not the present stage is at a high temperature heat treatment stage to predict a crack while comparing it with a reference value at the discriminated treatment stage to control temperature and humidity on the basis of predicted information to carry out control of the atmosphere so that no crack occurs in the timber, etc.
  • a model pattern of heat temperature/moisture percentage, an accumulated AE energy in that instance, and AE occurrence rate standardized at the time of high temperature heat treatment is as shown in Fig. 11. Further, a model pattern of temperature/moisture rate, an accumulated AE energy in that case, and AE occurrence rate standardized at the time of timber drying treatment is as shown in Fig. 16. In addition, a model pattern of temperature/moisture percentage, an accumulated AE energy in that instance, and an AE occurrence rate in the case of carrying out in consistency dry treatment and high temperature heat treatment is as shown in Fig. 17.
  • Fig. 1 is a graph in which temperature and pressure of the high temperature heat treatment (example 1) are recorded
  • Fig. 2 is a graph in which AE event number (occurrence rate) for each amplitude class of the high temperature heat treatment (example 1) is recorded
  • Fig. 3 is a graph in which AE occurrence rate of an amplitude of more than 1V of the high temperature heat treatment (example 1)
  • Fig. 4 is a graph in which an accumulated AE energy of an amplitude more than 1V of the high temperature heat treatment (example 1) is recorded
  • Fig. 5(a) is an explanatory view showing the state of a test specimen after experiment of the high temperature heat treatment (example 1)
  • Fig. 5(b) is a cross-sectional view showing the essential part thereof.
  • Fig. 6 is a graph in which temperature and pressure of the high temperature heat treatment (example 2) are recorded
  • Fig. 7 is a graph in which AE event number (occurrence rate) for each amplitude class of the high temperature heat treatment (example 2) is recorded
  • Fig. 8 is a graph in which AE occurrence rate of an amplitude of more than 1V of the high temperature heat treatment (example 2) is recorded
  • Fig. 9 is a graph in which an accumulated AE energy of an amplitude more than 1V of the high temperature heat treatment (example 2) is recorded
  • Fig. 10(a) is an explanatory view showing the state of a test specimen after experiment of the high temperature heat treatment (example 2)
  • Fig. 10(b) is a cross sectional view showing the essential part thereof.
  • Fig. 11 is an AE occurrence model pattern at the time of high temperature heat treatment
  • Fig. 12 is a model view showing temperature/humidity control and AE occurrence
  • Fig. 13 is a graph showing changes in the wood property at the time of high temperature heat treatment.
  • Fig. 14 is a graph in which temperature and AE occurrence rate of an amplitude of more than 1V of the drying treatment (example 3) is recorded
  • Fig. 15 is a graph in which accumulated AE energy of an amplitude of more than 1V of the drying treatment (example 3) is recorded
  • Fig. 16 shows an AE occurrence model pattern at the time of high temperature heat treatment
  • Fig. 17 shows an AE occurrence model pattern at the time of drying/high temperature heat treatment
  • Fig. 18 is a graph in which a temperature change of the high temperature heat treatment in the embodiment 1 is recorded
  • Fig. 19 is a graph in which AE event number (occurrence rate) for each respective amplitude class of an unprocessed material is recorded.
  • Fig. 14 is a graph in which temperature and AE occurrence rate of an amplitude of more than 1V of the drying treatment (example 3) is recorded
  • Fig. 16 shows an AE occurrence model pattern at the time of high temperature heat treatment
  • Fig. 20 is a graph in which AE event number (occurrence rate) for each respective amplitude class of the impregnation treated material of the embodiment 1 is recorded
  • Fig. 21 is a graph in which AE occurrence rate of an amplitude of more than 1V of the unprocessed or non-worked material of the embodiment 1 is recorded
  • Fig. 22 is a graph in which AE occurrence rate of an amplitude of more than 1V of the impregnation treated material of the embodiment 1 is recorded
  • Fig. 23 is a graph in which an accumulated AE energy of an amplitude of more than 1V of the unprocessed or non-worked material of the embodiment 1 is recorded
  • Fig. 24 is a graph in which accumulated AE energy of an amplitude of more than 1V of the impregnation treated material of the embodiment 1 is recorded
  • Fig. 25 is a graph showing an AE occurrence model pattern and a crack limit control reference by the accumulated AE at the time of high temperature heat treatment of the embodiment 1
  • Figs. 26(a) and (b) are explanatory views showing the state of a test specimen before and after the high temperature heat treatment according to the embodiment
  • Figs. 27(a) and (b) are explanatory views showing a cutting test state of a test timber subjected to temperature heat treatment according to the embodiment 1.
  • a naturally dried (moisture percentage 30%) natural raw timber log material (length of 200 mm x diameter of 80 ) of a maple tree is prepared.
  • This log material is first decompressed at room temperature to carry out deaeration of the timber thereafter to pressure-inject polyethylene glycol at 3 to 5 atm by a pressure pump.
  • the impregnated timber is inserted into high temperature water at more than 100°C to cause hydrothermal chemical reaction. It is to be noted in the case of carrying out high temperature heat treatment at more than 100°C that this treatment is not necessarily required as the pre-processing (hydrothermal chemical reaction), it is a matter of course to carry it out in a manner doubling as a subsequent high temperature heat treatment.
  • the log material pre-treated in this way and the same log material which has not been pre-treated are admitted into a thermal treatment chamber, and an AE sensor is attached to the materials through a wave guide.
  • the thermal treatment chamber internal side terminal of the wave guide is fixed to a section of the test timber by means of wood screws.
  • the wave guide is extended to the outside passing through a measurement hole provided in the thermal treatment chamber.
  • the AE sensor is attached to the externally extended portion of the wave guide, and is connected to a pre-amplifier, a cracking monitor, and a personal computer installed in the vicinity therewith. Then, air is deaerated from the thermal treatment chamber, and nitrogen gas is injected or introduced from an incombustible gas injection unit to provide an atmosphere of 97% incombustible gas.
  • thermocouple is caused to be operative to increase the temperature within the heat treatment chamber, and to inject vapour from a vapour insertion unit, thus to adjust humidity inside the chamber.
  • the temperature is raised up to 150°C at a stroke to carry out high temperature heat treatment of about 150 to 160°C for 22 hours thereafter to lower the temperature to a normal temperature in about two hours, thus to complete the treatment in about 24 hours.
  • Occurrence circumstances of AE for that time period was observed.
  • Fig. 19 shows AE event circumstances for each respective amplitude class of the untreated material in that instance.
  • Fig. 20 is a record indicating AE event occurrence circumstances for each respective amplitude class of the impregnation treated material.
  • AEs having an amplitude of more than 1V, with the amplification factor being set to 80 dB, within one minute to judge the present circumstances to fall within a crack warning zone when the accumulated event number is above a reference value, or when the amplitude is above a reference to allow the vapour injection unit to be operative to inject a large quantity of vapour into the heat treatment chamber in a short time to adjust humidity in the heat treatment chamber, and to control the operation of the heating unit to adjust temperature within the heat treatment chamber to control the atmosphere so as to maintain the state where no AE takes place from the timber, etc., the occurrence state where the AE signal is below a predetermined reference to allow the heating unit to be operative while carrying out such a control of atmosphere to gradually raise the temperature within the heat treatment chamber, thus to carry out a high temperature heat treatment for four hours at 160 to 180°C so that no cracking takes place in the timber, etc.
  • A1 and B1, B2 of reference photographs 4 show the compared results.
  • a cup byte of a lathe is used to carry out cutting of the wood section at 1580 rpm.
  • cutting quality of an edge tool is improved, and chips are successive in a belt shape (A1 of reference photograph 4).
  • the cutting surface is smooth.
  • the first invention of this application resides in a method of treatment to modify timber, etc., of impregnating a specific impregnant into timber, etc., to allow an hydrothermal chemical reaction (hydrolysis) to take place, to apply high temperature heat treatment to the timber, etc., in the atmosphere of an incombustible gas, wherein an approach is employed to detect acoustic emissions that the timber, etc., produces in accordance with a change of the timber structure in the high temperature heat treatment to detect cracking of the timber, etc., thus to carry out high temperature heat treatment while controlling the atmosphere so that no cracking occurs in the timber, etc., by using temperature and humidity as a control factor.
  • thermal plasticity is rendered to wood property.
  • the second invention of this application resides in a method of impregnating a specific organic impregnant into the timber, etc., to allow hydrothermal chemical reaction (hydrolysis), thereafter to carry out a heat drying process.
  • a drying treatment an approach is employed to detect AE as a signal to predict cracking of the timber, etc., to carry out atmosphere control by using temperature and humidity as a control factor. Accordingly, there is hardly any cracking during treatment.
  • the degree of drying is developed to a level less than 10% in this way, the impregnated timber, etc. is subjected to high temperature heat treatment in the atmosphere of an incombustible gas to render it the property of lignite or fossil wood.
  • an approach is employed to detect AE as a signal to predict cracking of the timber, etc., to carry out atmosphere control by using temperature and humidity as a control factor.
  • the third invention of this application resides in a method based on the methods of the first and second invention wherein an approach is employed to detect AE as a signal to analyze it to predict cracking to carry out high temperature heat treatment while preventing cracking by conducting the atmosphere control.
  • this third invention is characterized in that an approach is employed to have the ability of predicting in advance cracking of timber by analysis of AE. By adopting this approach, it has become possible to industrially and efficiently mass-produce timber, etc. having good yield and free from cracks.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

Le procédé décrit se fonde sur le fait que lorsqu'une fissure se produit dans un élément en bois à la suite d'un traitement thermique, il se produit une émission acoustique (AE). Selon le procédé, on détecte un signal d'émission acoustique effective se rapportant directement aux fissures, et le nombre total (intégré) d'évènements et le taux de survenance d'émissions acoustiques sont contrôlés tandis que le processus de traitement de séchage et le processus de traitement à haute température sont différenciés, de manière à réunir toutes les preuves susmentionnées afin de prévoir la formation de fissures pendant les processus de traitement de séchage et de traitement à haute température, la température et l'humidité étant régulées en fonction des informations prédites, afin de réguler l'atmosphère de manière à éviter la formation de fissures. Le bois est en outre imprégné avec un milieu solvant organique spécifique permettant d'effectuer le traitement d'imprégnation là où l'eau et la chaleur réagissant chimiquement entre elles, ce qui permet de plastifier l'intérieur de l'élément en bois et d'empêcher la formation de fissures provoquées par le traitement thermique, ainsi que d'éviter que le bois ne soit rendu fragile par le traitement à haute température, ce qui améliore l'aptitude du bois à être travaillé.
EP19900914969 1989-10-16 1990-10-16 Method of modifying treatment of timber and the like Withdrawn EP0496885A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP268410/89 1989-10-16
JP1268410A JP2717713B2 (ja) 1989-10-16 1989-10-16 木材等の改質処理法

Publications (2)

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EP0496885A1 true EP0496885A1 (fr) 1992-08-05
EP0496885A4 EP0496885A4 (en) 1992-09-23

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EP (1) EP0496885A4 (fr)
JP (1) JP2717713B2 (fr)
KR (1) KR920703279A (fr)
CA (1) CA2067824A1 (fr)
WO (1) WO1991005643A1 (fr)

Cited By (9)

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FR2786425A1 (fr) * 1998-11-27 2000-06-02 Arimpex Sarl Procede de traitement thermique d'un materiau ligno-cellulosique comportant un palier de refroidissement
FR2786426A1 (fr) * 1998-11-27 2000-06-02 Arimpex Sarl Procede de traitement thermique d'un materiau ligno-cellulosique avec elimination de l'oxygene en phase gazeuse
FR2786424A1 (fr) * 1998-11-27 2000-06-02 Arimpex Sarl Procede de traitement thermique d'un materiau ligno-cellulosique par confinement des gaz, et materiau ligno-cellulosique susceptible d'etre obtenu par ce procede
CN1056553C (zh) * 1993-01-12 2000-09-20 亚历山大·施密德梅尔 防止竹管裂开的方法
WO2001001056A1 (fr) * 1999-06-25 2001-01-04 The Regents Of The University Of California Baguette speciale et procede de detection d'emission acoustique ou de transmission ultrasonore pendant le sechage de sciage
US7814799B2 (en) 2005-09-09 2010-10-19 Korwensuun Konetehdas Oy Method for the determination of the stresses occurring in wood when drying
CN104385402A (zh) * 2014-09-22 2015-03-04 东北林业大学 一种木材表面负载无机纳米粒子保护层的方法
CN105643750A (zh) * 2016-02-25 2016-06-08 南京林业大学 竹筒的高效炭化及无裂缝处理方法
CN112629239A (zh) * 2020-12-23 2021-04-09 柳州市汇方科技有限公司 一种提高自动烘干设备的烘干效率的方法和装置

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JP5101134B2 (ja) * 2007-02-28 2012-12-19 志朗 坂 熱可塑性木質系バイオ材料の製造方法及び熱可塑性木質系バイオ材料
CN103753676A (zh) * 2013-12-11 2014-04-30 常熟市鑫磊木业制造厂 薄板炭化方法
CN106182274A (zh) * 2016-07-27 2016-12-07 阜南县大自然工艺品有限公司 一种竹子防开裂的干燥方法
CN106671237A (zh) * 2016-12-09 2017-05-17 广西北海浩邦新能源科技有限公司 一种林木炭化处理工艺
CN107914327A (zh) * 2017-11-02 2018-04-17 成都金川田农机制造有限公司 一种杨木的干燥工艺
CN118032794B (zh) * 2024-04-11 2024-06-25 沈阳欧施盾新材料科技有限公司 一种高压气瓶的瓶壁缺陷检测方法及系统

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SU1041811A1 (ru) * 1982-03-10 1983-09-15 Завод-Втуз При Производственном Объединении Турбостроения "Ленинградский Металлический Завод" Способ регулировани процесса горени черного целока

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1056553C (zh) * 1993-01-12 2000-09-20 亚历山大·施密德梅尔 防止竹管裂开的方法
FR2786425A1 (fr) * 1998-11-27 2000-06-02 Arimpex Sarl Procede de traitement thermique d'un materiau ligno-cellulosique comportant un palier de refroidissement
FR2786426A1 (fr) * 1998-11-27 2000-06-02 Arimpex Sarl Procede de traitement thermique d'un materiau ligno-cellulosique avec elimination de l'oxygene en phase gazeuse
FR2786424A1 (fr) * 1998-11-27 2000-06-02 Arimpex Sarl Procede de traitement thermique d'un materiau ligno-cellulosique par confinement des gaz, et materiau ligno-cellulosique susceptible d'etre obtenu par ce procede
WO2001001056A1 (fr) * 1999-06-25 2001-01-04 The Regents Of The University Of California Baguette speciale et procede de detection d'emission acoustique ou de transmission ultrasonore pendant le sechage de sciage
US7814799B2 (en) 2005-09-09 2010-10-19 Korwensuun Konetehdas Oy Method for the determination of the stresses occurring in wood when drying
CN104385402A (zh) * 2014-09-22 2015-03-04 东北林业大学 一种木材表面负载无机纳米粒子保护层的方法
CN105643750A (zh) * 2016-02-25 2016-06-08 南京林业大学 竹筒的高效炭化及无裂缝处理方法
CN105643750B (zh) * 2016-02-25 2018-04-27 南京林业大学 竹筒的高效炭化及无裂缝处理方法
CN112629239A (zh) * 2020-12-23 2021-04-09 柳州市汇方科技有限公司 一种提高自动烘干设备的烘干效率的方法和装置

Also Published As

Publication number Publication date
KR920703279A (ko) 1992-12-17
EP0496885A4 (en) 1992-09-23
JP2717713B2 (ja) 1998-02-25
WO1991005643A1 (fr) 1991-05-02
CA2067824A1 (fr) 1991-04-17
JPH03162902A (ja) 1991-07-12

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