JP4972626B2 - Wood coloring method and coloring apparatus - Google Patents

Description

  The present invention relates to an improvement in a coloring method and a coloring apparatus for wood used for building materials, for example.

  In general, when wood is heat-treated, it changes its color to brown due to the alteration of the wood components. This discoloration emphasizes the original grain, grain and knots of the wood, and emphasizes the woody feel of the wood. This heat treatment of wood is usually performed by drying to a level at which cracking does not occur in the wood, but if it is intended to obtain colored wood by slicing after the heat treatment, it is necessary to perform water absorption treatment of the wood again, etc. There is a problem that the process becomes complicated.

  In addition, in order to heat the flitch material excluding bark as a timber, it is necessary to heat it at a temperature of 100 ° C. or more. In order to prevent dry cracking of the surface due to the heating, the timber is always wetted further. However, the conventional coloring method does not cope with dry cracks on the surface accompanying heating.

  Therefore, various methods for coloring wood by high-pressure steam treatment have been proposed as a coloring method for heat treatment without drying the raw wood.

  For example, Patent Document 1 discloses that wood is treated with high-temperature steam in a compressed state inside a high-temperature and high-pressure container, so that cellulose, hemicellulose, and lignin, which are constituent components of wood, are altered and the whole is colored brown. A method for treating wood to be caused has been proposed.

In the case of such a method of coloring wood by high-pressure steam treatment, colored wood can be obtained by slicing after heat treatment without drying the wood or performing water absorption treatment again.
However, in the wood processing method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-155909, the wood surface is excessively dried when the wood returns from high pressure and high temperature to the atmospheric pressure in the final heat treatment stage. There was a problem of causing dry cracking.

  The present invention has been made in view of the above circumstances, and in the heating and coloring treatment using high-pressure steam, wood capable of shortening the processing time while preventing dry cracking of wood due to surface drying during pressure reduction treatment. It is an object of the present invention to provide a coloring method and an apparatus for carrying out the coloring method.

  In order to solve the above-described object, the wood coloring method according to claim 1 is a wood coloring method in which wood is colored by high-pressure steam treatment. After the wood is colored by high-pressure steam treatment, the high-pressure steam treatment is performed. It is characterized in that after the submerged wood is submerged, the pressure is reduced.

  The wood coloring method according to claim 2 is characterized in that, in claim 1, the wood is a sliced veneer.

  The wood coloring method according to claim 3 is characterized in that, in claim 1, the wood is a flitch material excluding bark having a moisture content of 33% or more (dry base).

  According to a fourth aspect of the present invention, there is provided the wood coloring method according to the third aspect, wherein the flitch material is constrained in a state where a plurality of the flitch materials are stacked with a spacer interposed therebetween, subjected to high-pressure steam treatment, and cooled in water. It is characterized by being.

  Claims 5 to 9 propose desirable processing conditions for each processing that the inventor has known in carrying out the method of the present invention.

  That is, the wood coloring method according to claim 5 is the method according to any one of claims 1 to 4, wherein the submergence of the wood maintains the pressure in a state in which the pressure is not lowered by 0.15 MPa or more from the pressure of the high-pressure steam treatment. It is characterized by being performed.

  The method for coloring wood according to claim 6 is characterized in that, in any one of claims 1 to 5, the pressure reduction treatment is performed after the wood has been cooled to a temperature of 115 ° C or lower. .

  The wood coloring method according to claim 7 is characterized in that, in any one of claims 1 to 6, the wood has one or more of vertical, horizontal, and length of 180 mm or less. .

  The wood coloring method according to claim 8 is characterized in that, in any one of claims 1 to 7, the heat treatment condition by the high-pressure steam treatment is an atmospheric temperature of 120 ° C or higher and 190 ° C or lower. .

The wood coloring method according to claim 9 is the method according to any one of claims 1 to 8, wherein in the high-pressure steam treatment, the difference between the center temperature and the ambient temperature of the wood is 10 ° C for 15 minutes or more. It is characterized by being held within.

  Further, in the tenth to thirteenth aspects, the wood coloring apparatus of the present invention is proposed.

  Here, the wood coloring apparatus according to claim 10 has a high-pressure high-temperature steam introduction port and an exhaust port, and is provided with at least a pedestal for placing the wood in a restrained state. After the high-pressure and high-temperature steam is introduced and the wood is colored by high-pressure steam treatment inside the high-pressure steam kettle, water is stored in the high-pressure steam kettle and the wood is restrained by the pedestal It is characterized in that after the water is submerged, the pressure is reduced.

  The wood coloring apparatus according to claim 11, wherein the water weir having at least a pedestal that has an inlet for high-pressure and high-temperature steam and an exhaust port and is placed in a state where the wood is constrained is provided as a high-pressure steam. The wood which is provided inside the pot, introduces the high-pressure and high-temperature steam, and after the wood is colored by high-pressure steam treatment inside the high-pressure steam pot, the water is stored in the water reservoir weir and the wood restrained by the pedestal It is characterized in that after the water is submerged, the pressure is reduced.

  The wood coloring apparatus according to claim 12, comprising a high-pressure steam kettle having an introduction port for high-pressure and high-temperature steam and an exhaust port, and at least holding means for holding the wood in a restrained state. After introducing high-temperature steam into the high-pressure steam kettle and coloring the wood restrained by the holding means in a high-pressure steam atmosphere, the pressure in the high-pressure steam kettle is held in a predetermined state. The cooling water is introduced into the high-pressure steam kettle, the wood is submerged in the cooling water and cooled, and then the pressure is reduced.

  The wood coloring apparatus according to claim 13 includes at least a water reservoir container having an introduction port for high-pressure and high-temperature steam and an exhaust port and having holding means for holding the wood in a restrained state. A high-pressure steam kettle provided, high-temperature steam is introduced into the high-pressure steam kettle, and the wood restrained by the holding means is exposed to a high-pressure steam atmosphere to develop a color; Is maintained in a predetermined state, cooling water is introduced into the water reservoir, the wood is submerged in the cooling water and cooled, and then the pressure is reduced.

  According to the wood coloring method of the present invention, the wood is colored by high-pressure steam treatment, so that the high-pressure steam penetrates into the wood and the wood is heat-treated in a wet state to develop color.

  Further, since the wood subjected to the high-pressure steam treatment is submerged before the pressure reduction treatment, not only can the wood be cooled quickly, but the surface of the wood is not excessively dried during the pressure reduction treatment. Therefore, dry cracking of the surface can be effectively prevented.

  In particular, according to the method for coloring wood according to claim 2, not only the surface of the sliced veneer can be prevented from dry cracking during the pressure reduction treatment, but also the subsequent wood processing is facilitated.

According to the method for coloring wood according to claim 3, in the flitch material , there is no hardening of the wood due to drying, and slicing after the treatment is easy.

In addition, when forming the laminated material to be sliced, if the method of the present invention is used, the flitch material is subjected to high-pressure steam treatment and then laminated and bonded. The color of the material can be easily controlled, and a material with little color variation can be obtained.

  For example, even if the obtained raw materials have color variations of the raw materials, high-pressure steam treatment is performed to reduce the color variations of the raw materials, or the sliced veneer with a more uniform color is manufactured by combining the colored raw materials can do.

Alternatively, various and highly accurate color management can be performed when manufacturing sliced single plates in which woods that have been intentionally colored in different colors are assembled and bonded and then sliced to disperse the colors in a mosaic pattern.

  In this way, various and highly accurate color management can be performed and cracking of the laminated material can be prevented, so that the yield can be increased in the production of sliced single plates.

  According to the method for coloring wood according to claim 4, since a plurality of materials are constrained in a state where they are stacked with spacers interposed therebetween and subjected to high-pressure steam treatment, a large number of flitch materials can be treated at a time. Not only can the flitch materials without bark stick together during processing, but the thickness of each can be prevented from changing, so that coloring without variation is possible.

  According to the method for coloring wood described in claims 5 to 8, in an environment where the high-pressure steam kettle is operated, the pressure, temperature, wood size, etc. are controlled under normal controllable conditions, so that the wood varies in color. It can be colored without.

That is, according to claims 5, 6, and 7, conditions such as pressure, temperature, and wood size can be controlled to easily prevent dry cracks on the surface.
That is, according to the method for coloring wood according to claim 5, the submergence of the wood is performed while maintaining the pressure in a state in which the pressure is not lowered by 0.15 MPa or more from the pressure of the high-pressure steam treatment, so that the surface is more effectively applied. Can prevent dry cracking.
Further, according to the wood coloring method of the sixth aspect, since the pressure reduction treatment is performed by cooling to a temperature of 115 ° C. or lower, it is possible to prevent dry cracking of the surface during the pressure reduction treatment.

  Furthermore, according to the method for coloring wood according to claim 7, since any one of vertical, horizontal, and length of wood is 180 mm or less, the inside can be quickly heated. For this reason, there is no possibility of cracking by the temperature gradient inside the wood during the temperature rise and cooling.

  Moreover, uniform coloring without color variation is obtained.

Moreover, if it is 180 mm or less, it will be easy to manufacture a slice veneer by carrying out the high-pressure steam process of the wood, and then carrying out the lamination | stacking adhesion | attachment and forming a laminated material, and then slicing.

  Further, according to the wood coloring method of claim 8, since the high-pressure steam treatment is performed at an atmospheric temperature of 120 ° C. or higher, it is possible to quickly color to a necessary concentration without color variation. Moreover, deterioration of wood can be effectively prevented by setting the upper limit to 190 ° C. or lower.

  Furthermore, according to the method for coloring wood according to claim 9, since the difference between the center temperature of the wood and the ambient temperature is kept within 10 ° C. for 15 minutes or more in the high-pressure steam treatment, It is possible to secure the energy required for this, and it is possible to further reduce the color variation between the center of the wood and the outer surface.

  According to the wood coloring apparatus of the tenth to thirteenth to thirteenth aspects, an apparatus that can efficiently implement the present invention can be simply configured by incorporating necessary equipment in the high-pressure steam kettle.

That is, according to the apparatus described in claims 10, 11, 12 , and 13 , the pedestal is provided in the high-pressure steam kettle, and the wood is submerged in a restrained state, so that when the cooling water is introduced into the high-pressure steam kettle, The condition of the high-pressure steam kettle changes by moving and changing the posture, etc., or the water vapor in the high-pressure steam kettle condenses, creating a negative pressure space in the high-pressure steam kettle, which is contained in the wood It is possible to prevent the water vapor from rapidly evaporating and causing surface cracks.

Moreover, according to the apparatus of Claims 11 and 13, since the water retaining weir or the water reservoir container is provided in the high-pressure steam kettle, water is stored therein, and the wood that is being accelerated at the holding means is submerged. It is desirable when coloring by laminating flitch materials and the like.

  In particular, since a water reservoir weir or water reservoir is installed inside the high-pressure steam kettle and cooling water is introduced into it, the thermal shock applied to the high-pressure steam kettle when introducing cooling water into the water reservoir weir or water reservoir Can be reduced.

  Also, reduce the cost of the equipment by using different materials, such as making only the water reservoir weir or water reservoir container that touches water with stainless steel, and using a material that is cheaper for the high-pressure steam kettle. Can do.

  Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a conceptual diagram illustrating a configuration of a wood coloring device 1 according to a first embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the coloring device 1. FIG. 3 is a flowchart showing a coloring procedure in the coloring apparatus 1.

  As shown in FIG. 1, the wood coloring device 1 includes a pedestal 3 for placing a wood 2 in a high-pressure steam kettle 4 in a constrained state.

  The pedestal 3 is fixed to the inside of the high-pressure steam kettle 4 while being supported by the support legs 5 from the inner wall surface of the high-pressure steam kettle 4, and includes an upper fixed beam 3a and a lower fixed beam 3b. The upper fixed beam 3a and the lower fixed beam 3b are configured to be openable and closable so that the wood 2 can be restrained. That is, the wood 2 is sandwiched between the upper and lower sides of the pressing plates 2a and 2b and placed between the upper fixed beam 3a and the lower fixed beam 3b of the base 3, and the bolt hole 3c of the lower fixed beam 3b. It is restrained by a bolt 3d screwed into (FIG. 2).

  The high-pressure steam kettle 4 is made of a stainless steel material from the viewpoint of minimizing metal contamination of the wood 2 as much as possible, and is configured to be divided vertically as shown in FIG. The inside of the high-pressure steam kettle 4 can be opened by attaching and detaching bolts 4a and nuts 4b.

  The high-pressure steam kettle 4 is provided with a high-pressure and high-temperature steam inlet 5a, an exhaust port 5b, and a pressurized water inlet 5c from the water tank 9 pressurized by the pressurized tank 8. A drain port 5e for draining the liquefied vapor through the steam trap 5d and a water drain port 5f are provided.

  The high-pressure and high-temperature steam inlet 5a, the outlet 5b, the water inlet 5c, the steam drain 5e, and the water drain 5f are respectively a steam inlet valve 6a, a steam exhaust valve 6b, The introduction valve 6c, the drain valve 6e, and the water discharge valve 6f adjust the flow rate of the fluid flowing through each of them.

  Next, with reference to FIG. 3, the coloring procedure of the timber 2 implemented using this timber coloring apparatus 1 is demonstrated.

  That is, in this wood coloring apparatus 1, first, a plurality of woods 2 are laminated in step S1. In this case, in the case of a flitch, spacers are used so that they stick to each other so that the substantial plate thickness does not increase.

  Next, in step S2, the uppermost surface and the lowermost surface of the plurality of laminated timbers 2 are sandwiched between pressing plates 2a and 2b.

  In step S3, the plurality of timbers 2 sandwiched between the pressing plates 2a and 2b are fixed to the base 3 in the empty high-pressure steam kettle 4.

  Then, in step S3-2, the high-pressure steam kettle 4 is closed, the steam introduction valve 6a, the steam exhaust valve 6b, and the drain valve 6e are opened, and the air in the high-pressure steam kettle 4 is replaced with steam.

  Thereafter, in step S4, the steam exhaust valve 6b is closed and the wood 2 is colored.

Here, when the wood 2 is colored, the wood 2 is preferably subjected to high-pressure steam treatment at a pressure of 0.1 MPa or more. In this embodiment, saturated steam is used for high-pressure steam treatment, and the temperature is determined by pressure. For example, when coloring wood at a temperature of 120 ° C., the saturated water vapor pressure at 120 ° C. is about 0.2 MPa , and the atmospheric pressure is 0.1 MPa, so that the processing pressure is 0.2 MPa−0.1 MPa = 0. .1 MPa.

Therefore, if the wood is subjected to high-pressure steam treatment at a pressure of 0.1 MPa or more, the wood 2 can be colored while preventing dry cracking of the surface more effectively.
If the ambient temperature is low, the coloring is slow and the coloring does not proceed. Therefore, the color cannot be colored to a necessary density, for example, the color remains initially varied. Moreover, when the temperature is high, the wood deteriorates.

  Therefore, it is preferable that the heat treatment conditions by the high-pressure steam treatment are heated in an atmosphere temperature of 120 ° C. or higher and 190 ° C. or lower.

  In order to reduce the color variation between the center and the outer surface of the wood 2 in the high-pressure steam treatment, the difference between the center temperature of the wood and the ambient temperature is made as small as possible and the temperature is maintained for a sufficient time. It is necessary to secure the energy required for coloring inside the interior.

In the high pressure steam treatment, for more than 15 minutes, it is preferable to maintain the difference between the center temperature and the ambient temperature of the timber 2 within 10 ° C..

  When the coloring is completed, in step S5, the water introduction valve 6c is opened, water is supplied into the high-pressure steam kettle 4, and the wood 2 fixed to the pedestal 3 remains in a high pressure state with a predetermined pressure applied. 2 is submerged in cooling water and cooled.

  At this time, if the pressure of the atmosphere decreases due to condensation of steam, the moisture of the wood evaporates and promotes dry cracking of the surface, so it is necessary to prevent the pressure from decreasing.

  Further, during submersion cooling, the space created in the steam kettle due to the replacement of high-pressure steam and water must be handled so that the heated steam filling it does not cause condensation and a vacuum is not generated. The submerged cooling is preferably performed while maintaining the pressure so that the pressure is not lowered by 0.15 MPa or more from the pressure of the high-pressure steam treatment.

  In addition, when the cooling water diffuses when the wood is submerged, and the steam condenses and the atmospheric pressure decreases, the moisture in the wood evaporates and promotes dry cracks on the surface, thus suppressing pressure fluctuations. Therefore, water must be introduced with appropriate calmness. Therefore, it is preferable to stabilize the water surface by introducing the cooling water so as to gradually and gently rise from below so that the water surface of the cooling water does not scatter.

  In order to shorten the cooling time, it is beneficial to circulate water. On the other hand, while introducing water, the introduced water is overflowed and drained, and fresh water is always supplied and continuously circulated to improve cooling efficiency.

  When the wood has been cooled to a temperature of 115 ° C. or lower (preferably 100 ° C. or lower), the steam exhaust valve 6b is opened in step S6, and the pressure in the high-pressure steam kettle 4 is reduced.

  In step S7, the water discharge valve 6f is opened to drain the water in the high-pressure steam kettle 4.

  In step S8, the high-pressure steam kettle 4 is opened, the wood 2 is taken out from the pedestal 3, and the process ends.

Thus, this coloring apparatus 1 introduces high-pressure and high-temperature steam, and after the wood 2 is colored by high-pressure steam treatment inside the high-pressure steam kettle 4, water is stored in the high-pressure steam kettle 4, and the pedestal The wood 2 restrained by 3 is submerged and cooled in a high pressure state, and then exhausted from the exhaust port 5b to perform a pressure reduction process.

  Next, a wood coloring device 11 according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a conceptual diagram showing a configuration of the wood coloring device 11 according to the second embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view of the coloring device 11. FIG. 6 is a flowchart showing a coloring procedure in the coloring apparatus 11.

  In the following description, the same members as those of the wood coloring apparatus 1 according to the first embodiment of the present invention are denoted by the same reference numerals, and redundant description will be omitted.

  As shown in FIGS. 4 and 5, the wood coloring device 11 is constituted by a high-pressure steam kettle 4 provided with a pedestal 3 for placing the wood 2 in a restrained state. It is the same as the coloring method and the coloring device 1 of the wood 2 according to the form.

  However, in the wood coloring method and coloring apparatus 11 according to the second embodiment, the pedestal 3 is provided in the water pool weir 12 provided inside the high-pressure steam kettle 4, and the high-pressure steam kettle 4. It is supported by the support leg 5 from the inner wall surface.

  In this way, since the area where water directly contacts the high-pressure steam kettle 4 is small, the thermal shock of the high-pressure steam kettle 4 during the cooling process can be mitigated.

  In the wood coloring apparatus 11 according to the second embodiment, the procedure for coloring the wood 2 is performed as shown in FIG.

  That is, first, in step S11, a plurality of woods 2 are stacked. In this case, in the case of flitch materials, spacers are used in order to prevent them from sticking to each other and increasing the substantial plate thickness.

  Next, in step S12, the uppermost surface and the lowermost surface of the plurality of laminated timbers 2 are sandwiched between the pressing plates 2a and 2b.

  In step S13, the plurality of timbers 2 sandwiched between the pressing plates 2a and 2b are fixed to the pedestal 3 in the empty water dam 12.

  Then, in step S13-2, the high-pressure steam kettle 4 is closed, the steam introduction valve 6a, the steam exhaust valve 6b, and the drain valve 6e are opened, and the air in the high-pressure steam kettle 4 is replaced with steam.

  Thereafter, in step S14, the steam exhaust valve 6b is closed and the wood 2 is colored.

  When the coloring is completed, in step S15, the water introduction valve 6c is opened, water is supplied into the water storage weir 12, and the wood 2 fixed to the pedestal 3 is submerged and cooled in a high pressure state.

  At this time, if the pressure of the atmosphere decreases due to condensation of steam, the moisture of the wood evaporates and promotes dry cracking of the surface, so it is necessary to prevent the pressure from decreasing. Therefore, it is preferable that the submerged cooling is performed while maintaining the pressure so that the pressure is not lowered by 0.15 MPa or more from the pressure of the high-pressure steam treatment.

  In step S16, the steam exhaust valve 6b is opened to depressurize the wood 2.

  In step S17, the water discharge valve 6f is opened to drain the water in the water reservoir weir 12.

  In step S18, the high-pressure steam kettle 4 is opened, the wood 2 is taken out from the pedestal 3, and the process ends.

Thus, after introducing the high-pressure high-temperature steam and coloring the wood 2 by high-pressure steam treatment inside the high-pressure steam kettle 4, the water 2 is stored in the water weir 12 and the wood 2 restrained by the pedestal 3. Is submerged and cooled in a high pressure state, and then exhausted from the exhaust port 5b to perform a pressure reduction process.

  Here, with reference to the table | surface of FIG. 7, the Example using the above-mentioned timber coloring apparatuses 1 and 11 is described. FIG. 7 is a table summarizing the evaluation results of each example.

  In FIG. 7, Example 1 is a coloring example of wood 2 performed using the wood coloring apparatus 1 according to the first embodiment.

That is, in Example 1, the wood 2 has a size of 170 mm (thickness) x 140 mm (width) x 485 mm (length) and a moisture content of 35% to 110%. For example, a temperature increase from 30 ° C. to 160 ° C. (transition time 30 minutes) with high-pressure steam and a heat treatment with 160 ° C. and 120 minutes holding with high-pressure steam were performed. Then until the product is submerged. Water was poured in as if the water was pushed up from the bottom, and the temperature was lowered.
At this time, if the size of the wood is large, the inside cannot be quickly heated. For this reason, a temperature gradient inside the wood occurs during heating and cooling, and it may break due to thermal strain.

  Further, color variation occurs between the surface and the inside, and uniform coloring cannot be obtained.

  Therefore, it is preferable that any one or more of the vertical, horizontal, and length of the wood is 180 mm or less.

  At this time, if the high pressure state to be maintained after the heat treatment is reduced by 0.15 Mpa or more from the heat treatment pressure, dry cracking occurs, and therefore, it is preferably maintained at the same level or higher than the heat treatment pressure. Therefore, the pressure fluctuation was controlled with high-pressure air so as not to decrease by 0.15 Mpa or more from the heat treatment pressure. The cooling time required 30 minutes.

  After that, the timber 2 is sized and laminated and glued so that the final overall size is 170 mm (thickness) x 317 mm (width) x 1860 mm (length). Formed.

  Example 2 is a coloring example of the wood 2 performed using the wood coloring device 11 according to the second embodiment. In other words, in the second embodiment, the water weir 12 for storing water is disposed in the high-pressure steam kettle 4 to alleviate the thermal shock of the high-pressure steam kettle 4. Other conditions are the same as in the first embodiment.

  In Example 3, a slice veneer was used instead of the flitch in Example 1. That is, forty slices of oak wood having a size of 0.25 mm × 300 mm × 600 mm and a water content of 35-110% were loaded.

  Other conditions are the same as in the first embodiment.

  Further, Comparative Example 1 is a case where the pressure reduction process is performed simultaneously with the temperature lowering without injecting high-pressure water in Example 1, and other conditions are the same as Example 1.

  As evaluation items, the occurrence of dry cracks was confirmed, and the yield rate was calculated. Here, the non-defective product rate indicates the yield of the sliced single plate after the flitch assembly for the flitches of Examples 1 and 2 and Comparative Example 1. Moreover, about the slice single board (Example 3), the yield with a single board is shown.

  FIG. 7 also compares the product temperature at the end of processing and the container temperature of the high-pressure steam kettle 4. Since it is preferable that the high-pressure steam kettle 4 be gradually cooled in consideration of metal fatigue, the container temperature of the high-pressure steam kettle 4 at the end of the treatment is considered to be less deteriorated as it approaches the treatment temperature (160 ° C. this time). .

  The evaluation results are as follows. That is, the non-defective product rate is 96% (◯) in Example 1, 97% (O) in Example 2, 95% (O) in Example 3, and twisting and cracking in the comparative example 1 0% (×).

  Next, the product temperature (container temperature) is 42 ° C. (54 ° C.) in Example 1, 45 ° C. (127 ° C.) in Example 2, 42 ° C. (54 ° C.) in Example 3, and Comparative Example 1. Was 92 ° C. (133 ° C.).

  Here, the product temperature and the container temperature will be described. Since the container temperature is closer to the processing temperature (160 ° C.) at the end of the processing, the deterioration is considered to be less. Therefore, the example 2 is the most preferable among the examples. Comparative Example 1 seems to have little deterioration, but it can be seen that the product temperature is as high as 92 ° C. and the cooling efficiency is low.

  From the above, the overall evaluation is as follows: Example 1 is (◯), Example 2 is (◎), Example 3 is (○), Comparative Example 1 is (×), and coloring device 11 having a water weir 12 is provided. Example 2 of the flitch by the coloring device 1 is the best, followed by Example 1 of the flitch by the coloring device 1 and Example 3 of the sliced veneer by the coloring device 1, followed by lowering the temperature without injecting high-pressure water in the coloring device 1. It turned out that the comparative example 1 in the case of the flitch which performed the pressure | voltage reduction process simultaneously is the worst.

  As described above, according to the present invention, not only the flitch and slice veneer containing moisture can be directly subjected to the thermal coloring process, but also the coloring process can be easily performed as compared with the conventional coloring method.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a conceptual diagram showing a configuration of a wood coloring device according to a third embodiment of the present invention, and FIG. 9 is a schematic cross-sectional view of the coloring device of FIG. FIG. 10 is a flowchart showing a coloring procedure in the coloring apparatus of FIG. In the following description, the same members as those of the wood coloring apparatus 1 according to the first embodiment of the present invention are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIGS. 8 and 9, in the wood coloring device 21, the high-pressure steam pot 24 includes a water reservoir 25 having a pedestal 23 as a holding means for holding the wood 2 in a constrained state. In preparation.

  The pedestal 23 is the same as the wood coloring apparatus 1 in that the pedestal 23 includes an upper fixed beam 3a, a lower fixed beam 3b, and pressing plates 2a and 2b. FIG. 9 shows an example of a flitch, in which the wood 2 is sandwiched from the upper and lower sides by the pressing plates 2a and 2b, and the base 23 is fixed to the upper side with the spacers 7a and 7b interposed in order to secure a gap. It is placed and restrained between the beam 3a and the lower fixed beam 3b.

  The pedestal 23 is fixed in a water reservoir 25, and the water reservoir 25 is moved and fixed by a wheel 27 inside the high-pressure steam kettle 24 while being supported by the rail 26 from the inner wall surface of the high-pressure steam kettle 24. It is provided as possible.

  As described above, since the high-pressure steam kettle 24 and the water reservoir 25 are provided separately, the thermal shock applied to the high-pressure steam kettle 24 when introducing the cooling water into the water reservoir 25 can be reduced. As a result, the high-pressure steam The safety of the pressure vessel of the pot 24 is also increased.

  In addition, it is possible to reduce the cost of the apparatus by using different materials such as manufacturing only the water reservoir 25 that touches water with stainless steel, and adopting a material that is cheaper than the high-pressure steam pot 24. it can.

  The high-pressure steam pot 24 is configured to be divided in the longitudinal direction. The high-pressure steam pot 24 is configured so that the water reservoir 25 can be taken out together with the pedestal 23 by opening and closing the lid 24c by attaching and detaching the flanges 24a and 24b by a bolt nut mechanism or a clamp mechanism (not shown). It has become.

  The high-pressure steam kettle 4 is provided with a high-pressure and high-temperature steam inlet 5a, an exhaust port 5b, and a pressurized water inlet 5c from the water tank 9 pressurized by the pressurized tank 8. A drain port 5e for draining the liquefied steam through the steam trap 5d and a water drain port 5f, a steam introduction valve 6a, a steam exhaust valve 6b, a water introduction valve 6c, a drain valve 6e, a drain The valve 6f is provided in the same manner as the wood coloring apparatus 1.

  Also here, as the wood 2, a beech flitch material having a wet moisture content of 33% or more (moisture content: 33 to 67% dry base raw material) that has not been subjected to a drying treatment is employed.

  Further, the wood 2 has one or more of length, width, and length of 180 mm or less. In this embodiment, the size is 42 mm (thickness) × 140 mm (width) × 450 mm (length), and the L * value of the colorimeter varies from 59 to 83.

  Next, with reference to FIG. 10, the coloring procedure implemented using this wood coloring device 21 will be described.

  In the wood coloring device 21, first, in step S <b> 21, a plurality of woods 2 are stacked with spacers 7 a and 7 b interposed therebetween, and a gap between the woods 2 is secured.

  Next, in step S22, the pressing plates 2a and 2b are sandwiched between the uppermost and lowermost surfaces of the plurality of laminated timbers 2.

  Further, in step S23, the plurality of timbers 2 sandwiched between the pressing plates 2a and 2b are fixed to the base 23 which is a holding means in the empty high-pressure steam kettle 24.

  Then, in step S23-2, the water reservoir 25 is inserted into the high-pressure steam pot 24. A drain pipe and a drain pipe are also connected to the bottom of the water reservoir 25 and connected to a water drain port 5f and a drain port 5e, respectively, and the lid 24c is closed and closed.

  In step S23-3, the steam introduction valve 6a, the exhaust valve 6b, and the drain valve 6e are opened to replace the air in the hook with steam.

  In step S24, the exhaust valve 6b is closed, and high pressure steam is supplied into the high pressure steam pot 24 to color the wood 2.

  Then, when the coloring is completed, in step S25, the steam introduction valve 6a is closed, and the water introduction valve 6c is opened in the high-pressure steam pot 24 while being pressurized and water is supplied to fix the wood to the base 23. 2 is submerged.

  At this time, the water introduction valve 6c is opened, water is inserted into the high-pressure steam kettle 24 (0.7 MPa), and the wood 2 fixed to the pedestal 23 is submerged and cooled in a high-pressure state. At that time, the pressure in the high-pressure steam pot 24 is managed so as not to drop. To lower the pressure, the steam introduction valve 6a is opened auxiliary, or the pressure of water is increased. Further, when the pressure rises too much, it is controlled by the steam exhaust valve 6b. In order to further increase the cooling efficiency, the water is circulated while adjusting by overflowing.

  When the cooling is completed, in step S26, the steam exhaust valve 6b is opened, and the high-pressure steam pot 24 is subjected to a pressure reduction process. Further, after the drain valve 6f is opened and the cooling water in the water reservoir 25 is discharged, the drain pipe and drain pipe connected to the water drain port 5f and the drain port 5e, respectively, are removed from the water reservoir 25.

  After the drain valve 6f is opened and the cooling water in the water reservoir 25 is discharged, the water reservoir 25 is taken out from the high-pressure steam pot 24 in step S26-2.

  Finally, in step S27, the wood 2 is taken out from the pedestal 23 of the holding means, and the process ends.

  Here, experimental examples (Examples 2-1, 2-2, and 2-3, Comparative Examples 2-1, 2-2, and 2-3) performed using the above-described wood coloring device 21 will be described.

In Example 2-1, when the size is 42 mm (thickness) × 140 mm (width) × 450 mm (length) and the L * value of the colorimeter varies from 59 to 83, the temperature reaches 135 ° C. in 30 minutes. The temperature was raised and high-pressure steam treatment was performed for 1 hour at 135 ° C. (The center temperature was held for 0.7 hours at 125 ° C. or higher)
Thereafter, 0.7 MPa of pressurized water was inserted and cooled for 30 minutes, then released to atmospheric pressure and taken out.

Thus, in this high-pressure steam treatment, in order to ensure the interior of the energy required for coloring, for more than 15 minutes, and to hold the difference between the center temperature and the ambient temperature of the timber 2 within 10 ° C. .

  Thereafter, the heat-treated wood 2 is subjected to dimensional adjustment and surface finishing with a molder and a saw, and an adhesive is applied to the surface, and then laminated and bonded with a press.

  Then, the laminated wood 2 was sliced to a thickness of 0.25 mm with a slicer.

  Example 2-2 is obtained by increasing the flitch size in Example 2-1. Tree species, moisture content, and L * value of the colorimeter are the same as in Example 2-1.

In Example 2-2, since the size was 180 mm (thickness) × 180 mm (width) × 450 mm (length), the temperature was raised to 135 ° C. in 30 minutes, and the flitch size was large. High-pressure steam treatment was performed for 4 hours longer than (1 hour). (The center temperature was held for 0.5 hours at 125 ° C. or higher)
Thereafter, 0.7 MPa of pressurized water was inserted and cooled for 2 hours, then released to atmospheric pressure and taken out.

Glue bonding and slicing are the same as in Example 2-1.

  Example 2-3 is a case where the heat treatment time is shortened in Example 2-1, and the tree species, flitch size, moisture content, and L * value of the colorimeter are the same as those of Example 2-1.

  In this Example 2-3, the temperature was raised to 135 ° C. in 30 minutes, which was the same as in Example 2-1, but a high-pressure steam treatment was performed for 0.3 hours shorter than that in Example 2-1 (1 hour). It was. The center temperature was 125 ° C. or higher as in Example 2-1, but the retention time was only 0.1 hour compared to 0.7 hours in Example 2-1. .

Water-cooling conditions, assembly adhesion and slicing are the same as in Example 2-1.

  Comparative Example 2-1 is a case where the heat treatment temperature is too high in Example 2-1, and the tree species, flitch size, moisture content, and L * value of the colorimeter are the same as in Example 2-1.

In this comparative example 2-1, in 30 minutes, the temperature was raised to 195 ° C., which was 60 ° C. higher than that in Example 2-1, and the high-pressure steam treatment was performed for the same 1 hour as in Example 2-1 (1 hour). (The center temperature was held at 185 ° C. or higher for 0.25 hours)
Thereafter, 0.16 MPa of pressurized water was inserted and cooled for 45 minutes, then released to atmospheric pressure and taken out.

Glue bonding and slicing are the same as in Example 2-1.

  Comparative Example 2-2 is a case where the size of the wood 2 is too large in Example 2-1, and the tree species, flitch size, moisture content, and L * value of the colorimeter are the same as in Example 2-1. is there.

In Comparative Example 2-2, the size of 200 mm (thickness) × 200 mm (width) × 450 mm (length) was raised to 135 ° C. in 30 minutes, and the flitch size was large. A high-pressure steam treatment was performed for 5 hours longer than 1 (1 hour). (The center temperature was held for 0.5 hours at 125 ° C. or higher)
Thereafter, 0.7 MPa of pressurized water was inserted and cooled for 2.5 hours, then released to atmospheric pressure and taken out.

Glue bonding and slicing are the same as in Example 2-1.

  Comparative Example 2-3 is a case where water cooling is not used in the cooling process in Example 2-1, and the can is left as it is, and the tree type, flitch size, water content, and L * value of the colorimeter are Same as Example 2-1.

In Comparative Example 2-3, as in Example 2-1, high-pressure steam treatment was performed in which the temperature was raised to 135 ° C. in 30 minutes and held for 1 hour. (The center temperature was held for 0.7 hours at 125 ° C. or higher as in Example 2-1.)
Thereafter, the pressurized water was not inserted and the container was left as it was in the closed kettle and cooled from 135 ° C. to 102 ° C. for 5 hours, then released to atmospheric pressure and taken out.

Glue bonding and slicing are the same as in Example 2-1.

  FIG. 11 is a table summarizing the evaluation results of the raw material yield and product color variation of each of the above experimental examples using the wood coloring device 21 of FIG. The color variation indicates the L * value of the product. Evaluation was represented by symbols ◎ (very good), ○ (good), △ (normal), and × (poor).

According to this, the raw material yield, as in Example 2-1, a full rich size slightly larger in Example 2-2, and Example 2-3 of the heat treatment time is short is, bend respectively, 95% (crack 5 %) O, 86% (cracking, bending 14%) O, 97% (cracking bending 3%) O were all good, and Example 2-3 with the short heat treatment time was the best.

  On the other hand, in the comparative examples, both are poor x, natural cooling comparative example 2-3 is 55% (cracking 45%) x, and heat treatment temperature is too high comparative example 2-1 is 25% (cracking, Deterioration 75%) ×, and the size of the wood was too large Comparative Example 2-2 was 15% (crack 75%) ×, and the raw material yield decreased in this order.

  Next, color variation before processing is L * 59 to 83 (MAX-MIN = 24), whereas Example 2-3 in which the heat treatment time is short is L * 39 to 73 (MAX-MIN = 34). Example 2-1 was the best except that it was Δ), L * 39 to 48 (MAX−MIN = 9) O, and then Example 2-2 with a slightly larger flitch size was L. * It was good with 42-53 (MAX-MIN = 11) O.

  On the other hand, in the comparative example, comparative example 2-1 whose heat treatment temperature is too high is L * 29 to 38 (MAXM-IN = 9) O, and natural cooling comparative example 2-3 is L * 38 to 47 ( MAX-MIN = 9) O, but Comparative Example 2-2 in which the size of the wood was too large was L * 40 to 55 (MAX-MIN = 15) Δ.

  As a result, the overall evaluation is that Example 2-1 is the best, ◎, then the flitch size is slightly larger Example 2-2 is good O, and the heat treatment time is shorter in Example 2-3. In contrast, Comparative Example 2-1 in which the heat treatment temperature was too high, Comparative Example 2-2 in which the size of the wood was too large, and Comparative Example 2-3 in natural cooling were all poor.

As described above , according to the coloring apparatuses 1, 11, 21 and the respective coloring methods of the above embodiment, the wood 2 is colored by high-pressure steam treatment, so that the high-pressure steam penetrates into the wood 2 and the wood 2 is Colored by heat treatment in a wet state.

  Further, since the wood 2 that has been subjected to the high-pressure steam treatment is submerged before the pressure reduction treatment, not only can it be cooled quickly, but the surface of the wood 2 is not excessively dried during the pressure reduction treatment. Therefore, dry cracking of the surface can be effectively prevented.

In particular, the veneer to be sliced, it is possible not only to prevent drying cracks on the surface during the step-down processing, wood processing after is facilitated.

Moreover, when the flitch material without a bark whose moisture content is 33% or more (dry base) is used, there is no hardening of the wood 2 due to drying, and slicing after the treatment is easy.

  Also, when forming a sliced laminated material, if the method of the present invention is used, the flitched material is laminated and bonded after high-pressure steam treatment, so that the laminated material is compared with the colored material after forming the laminated material. Color control can be easily performed, and a product with little color variation can be obtained.

  For example, even if the obtained raw materials have color variations of the raw materials, high-pressure steam treatment is performed to reduce the color variations of the raw materials, or the sliced veneer with a more uniform color is manufactured by combining the colored raw materials can do.

Alternatively, a variety of highly accurate color management can be performed when manufacturing sliced single plates in which the timbers 2 which are intentionally colored in different colors are assembled and bonded, and then sliced to vary the colors in a mosaic shape. .

  In this way, various and highly accurate color management can be performed and cracking of the laminated material can be prevented, so that the yield can be increased in the production of sliced single plates.

  Furthermore, if high pressure steam treatment is performed by constraining a plurality of materials in a stacked state with spacers interposed, not only can a large number of flitch materials be processed at once, but also bark-free flitch materials can be treated together. Since it is possible to prevent the thicknesses from sticking to each other and changing, the coloring can be performed without variation.

In addition, under the environment where the high-pressure steam pots 4 and 24 are operated, the pressure, temperature, size of the wood 2 and the like are controlled under normal controllable conditions, so that the wood 2 can be easily colored without color variation.

  That is, the submergence of the wood 2 is performed while maintaining the pressure in a state where the pressure is not lowered by 0.15 MPa or more from the pressure of the high-pressure steam treatment, so that dry cracking of the surface can be more effectively prevented.

  In addition, since the pressure is lowered to 115 ° C. or lower, the surface can be prevented from cracking during the pressure reduction.

  Furthermore, since one or more of the vertical, horizontal, and length of the wood 2 is 180 mm or less, the temperature inside can be quickly raised. Therefore, the temperature gradient inside the wood 2 does not break when the temperature is raised or cooled. Moreover, uniform coloring without color variation is obtained.

Moreover, if it is 180 mm or less, it will be easy to manufacture a slice single board by carrying out the high-pressure steam process of the wood 2, and carrying out the lamination | stacking adhesion | attachment and forming a laminated material, and then carrying out a slice process .

  In addition, since the high-pressure steam treatment is performed at an atmospheric temperature of 120 ° C. or higher, it is possible to more quickly color to a required concentration without color variation. Moreover, deterioration of the timber 2 can be effectively prevented by setting the upper limit to 190 ° C. or less.

  Furthermore, since the difference between the center temperature and the ambient temperature of the wood 2 is kept within 10 ° C. for 15 minutes or more in the high-pressure steam treatment, it is possible to secure the energy necessary for coloring inside the wood 2. The color variation between the center of the wood 2 and the outer surface can be further reduced.

  In addition, according to these wood coloring devices 1, 11, and 21, by incorporating necessary equipment in the high-pressure steam kettles 4 and 24, an apparatus that can efficiently implement the present invention can be easily configured.

  That is, according to these coloring devices 1, 11, and 21, the high-pressure steam kettles 4 and 24 are provided with the pedestals 3 and 23, and the wood 2 is submerged in a state of being restrained by the pedestals 3 and 23. When the cooling water is introduced into 24, the condition of the high-pressure steam kettles 4, 24 is changed by moving the wood 2 and changing the posture, etc. It is prevented in advance that a negative pressure space is generated in the hooks 4 and 24, and the water vapor contained in the wood 2 is rapidly evaporated to cause surface cracks.

  Further, according to these coloring apparatuses 11 and 21, the water storage weir 12 or the water storage container 25 is provided in the high-pressure steam pots 4 and 24, water is stored therein, and the wood 2 accelerated by the holding means is submerged. Therefore, it is desirable when a thick flitch material or the like is laminated and colored.

  In particular, since the water reservoir weir 12 and the water reservoir container 25 are provided inside the high-pressure steam pots 4 and 24 and the cooling water is introduced therein, when the cooling water is introduced into the water reservoir weir 12 and the water reservoir container 25, Thermal shock applied to the high-pressure steam kettles 4 and 24 can be reduced.

  In addition, only the reservoir weir 12 and the reservoir 25 that come into contact with water are made of stainless steel, and the high-pressure steam pots 4 and 24 are made of materials that are cheaper than that. Cost can be reduced.

  The above-described embodiment is merely a preferred specific example of the present invention, and the present invention is not limited to the above-described embodiment.

  For example, the holding means is not limited to the configuration such as the illustrated pedestals 3 and 23. FIG. 12 is an explanatory view showing a configuration in which the wood 2 is restrained by a metal basket 35 as a holding means. In the coloring apparatus 31 of FIG. 12, the metal basket 35 includes a net basket 35a and a basket base 35b, and can store a plurality of wood 2 stacked by opening the top of the net basket 35a. In this coloring device 31, a plurality of timbers 2 stacked via a spacer 7a are packed in a metal cage 35 and subjected to high-pressure steam treatment, and the timber 2 is submerged while preventing the timber 2 from floating by the metal cage 35. It is configured to cool. Thus, various holding means can be employed as long as the structure can hold the wood 2 in a restrained state.

  The material of the high-pressure steam pots 4 and 24 is not limited to stainless steel. Considering metal contamination of the wood 2, stainless steel is preferable for the pressure vessel, but other materials can be adopted.

  Moreover, in this embodiment, the wood 2 is not limited to the beech material of the moisture base which has not performed the drying process: 33-67% dry base (raw material). Various substrates can be used, and various design changes can be made in size. Various design changes can be made to the assembly and slicing conditions.

  In addition, the wood 2 is applied to the flitch and slices loaded with single plates, but can also be applied to other wood 2 such as interior materials, furniture materials, decorative wood materials manufactured by slicing, etc. is there.

  The heat treatment with high-pressure steam is preferably 120 ° C. or more and 190 ° C. or less. However, when the treatment temperature is 130 ° C. (treatment pressure 0.175 MPa) or less, the submerging of the wood 2 is caused by high-pressure steam treatment. It is preferable to maintain the pressure in a state where the pressure does not drop 0.08 MPa or more from the pressure.

  In this embodiment, high-pressure air is used for maintaining the pressure. However, for example, when nitrogen gas or the like is used, oxidation of the wood 2 can be suppressed.

  Moreover, although the pressurization means of water is not specifically limited, use of a high-pressure water tank or a high-pressure pump is preferable.

  Although the required cooling temperature inside the wood 2 varies depending on the size and tree species, it is generally considered to be about 115 ° C. or less, desirably 105 ° C. or less.

  In addition, it goes without saying that various design changes are possible within the scope of the claims of the present invention.

It is a conceptual diagram which shows the structure of the coloring apparatus of the wood of the 1st Embodiment of this invention. It is sectional drawing of the outline of the coloring apparatus of FIG. It is a flowchart which shows the coloring procedure in the coloring apparatus of FIG. It is a conceptual diagram which shows the structure of the coloring apparatus of the wood of the 2nd Embodiment of this invention. FIG. 5 is a schematic cross-sectional view of the coloring device of FIG. 4. It is a flowchart which shows the coloring procedure in the coloring apparatus of FIG. It is the table | surface which put together the evaluation result of Example 1, 2, 3 and the comparative example 1. FIG. It is a conceptual diagram which shows the structure of the coloring apparatus of the wood of the 3rd Embodiment of this invention. FIG. 9 is a schematic cross-sectional view of the coloring device of FIG. 8. It is a flowchart which shows the coloring procedure in the coloring apparatus of FIG. It is the table | surface which put together the evaluation result about the yield of the raw material of the above-mentioned each experimental example using the wood coloring apparatus of FIG. 8, and the color variation of a product. It is explanatory drawing which shows the structure which restrains a timber to the metal basket as a holding means.

1, 11, 21 Wood coloring device 2 Wood 3, 23 Base (holding means)
4, 24 High-pressure steam kettle 4c High-pressure high-temperature steam inlet 4d High-pressure high-temperature steam exhaust 12 Water reservoir 25 Water reservoir

Claims (13)

In the wood coloring method of coloring wood by high-pressure steam treatment,
A method for coloring wood, comprising: coloring the wood by high-pressure steam treatment, submerging the wood subjected to high-pressure steam treatment, and then performing pressure reduction treatment. In claim 1,
The wood is a sliced veneer, wherein the wood is colored. In claim 1,
A wood coloring method, wherein the wood is a flitch material excluding bark having a moisture content of 33% or more (dry base). In claim 3,
A wood coloring method, wherein a plurality of the flitch materials are constrained in a state where they are stacked with a spacer interposed therebetween, are subjected to high-pressure steam treatment, and are submerged and cooled. In any one of Claims 1 thru | or 4,
The wood coloring method characterized in that the submergence of the wood is performed while maintaining the pressure so that the pressure is not lowered by 0.15 MPa or more from the pressure of the high-pressure steam treatment. In any one of Claims 1 thru | or 5,
The method of coloring wood, wherein the pressure reduction treatment is performed after the wood is cooled to a temperature of 115 ° C. or lower. In any one of Claims 1 thru | or 6,
The wood is characterized in that any one or more of length, width and length is 180 mm or less. In any one of Claims 1 thru | or 7,
A method for coloring wood, wherein the heat treatment condition by the high-pressure steam treatment is an atmospheric temperature of 120 ° C. or higher and 190 ° C. or lower. In any one of Claims 1 thru | or 8,
Above in the high pressure steam treatment, for more than 15 minutes, the coloring method of the wood, characterized in that to hold the difference between the center temperature and the ambient temperature of the timber within 10 ° C.. A high-pressure steam kettle having an introduction port for high-pressure and high-temperature steam and an exhaust port and provided with at least a pedestal for placing the wood in a restrained state;
After introducing the high-pressure and high-temperature steam and coloring the wood by high-pressure steam treatment inside the high-pressure steam kettle, water is stored in the high-pressure steam kettle and the wood restrained by the pedestal is submerged. This is a wood coloring device that has been designed to reduce pressure. A high-pressure steam kettle is provided with a water reservoir weir having an introduction port for high-pressure and high-temperature steam and an exhaust port, and at least a pedestal for placing the wood in a restrained state.
After introducing the high-pressure high-temperature steam and coloring the wood by high-pressure steam treatment inside the high-pressure steam kettle, the water is stored in the water reservoir weir and the wood restrained by the pedestal is submerged. A wood coloring device that is designed to perform pressure reduction. A high-pressure steam kettle having an introduction port for high-pressure and high-temperature steam and an exhaust port, and at least holding means for holding the wood in a restrained state;
After introducing high-temperature steam into the high-pressure steam kettle and coloring the wood restrained by the holding means in a high-pressure steam atmosphere, the pressure in the high-pressure steam kettle is held in a predetermined state. A wood coloring apparatus in which cooling water is introduced into the high-pressure steam kettle, the wood is submerged in the cooling water and cooled, and then the pressure is reduced. A high-pressure steam kettle provided with at least a water reservoir having a holding means for holding a high-pressure and high-temperature steam introduction port and an exhaust port and holding the wood in a restrained state;
After introducing high-temperature steam into the high-pressure steam kettle and coloring the wood restrained by the holding means in a high-pressure steam atmosphere, the pressure in the high-pressure steam kettle is held in a predetermined state. A wood coloring device in which cooling water is introduced into the water reservoir, the wood is submerged in the cooling water and cooled, and then the pressure is reduced.

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