JPS6033643B2 - Method for correcting and preventing warped materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to restore wood that has been distorted during the drying process to a wood that is free from distortion, and to prevent distortion from occurring again. It was developed for the purpose of making wood that does not generate wood.

Sawn lumber products are affected by uneven moisture content that the wood itself has from the time it is standing, uneven moisture content due to differences in the timing of felling and sawing, uneven moisture content that occurs during transportation of sawn timber products, etc. Even in products, there are parts with high moisture content and parts with low moisture content.

If such lumber products with uneven moisture content distribution are subjected to natural drying without controlling temperature or humidity, or artificial drying such as hot air drying, vacuum drying, SV method, etc. without correcting the uneven moisture content, It is well known that a difference in the moisture content distribution always causes a difference in the shrinkage rate, and that the material with the larger shrinkage rate is drawn to the side, causing distortion. In addition, even if the sawn timber product is prone to distortion, it can be treated by applying appropriate humidity immediately after sawing.
It has long been well known that if the material is allowed to dry gradually over a long period of time, no distortion will occur.

For these reasons, in order to correct the uneven moisture content of sawn lumber products from the time of standing, etc., we can increase the moisture content of areas with low moisture content without increasing the moisture content of areas with high moisture content. If you make the distribution uniform and then lower the moisture content while maintaining a uniform moisture content distribution, uneven shrinkage will not occur.
It is thought that this will result in a lumber product that does not generate distortion.

In addition, water is forced into the cell cavities of the sawn lumber where distortion has occurred, and the product gradually expands, returning to the state immediately after sawn where no distortion has occurred, and further adding moisture to areas with low moisture content. If the moisture content is increased, the uneven moisture content distribution that existed at the time of tree standing will be corrected, so if the moisture content is subsequently lowered as described above, the distortion will also be corrected even in the wood that was already distorted. It is thought that this will result in wood that does not burn.

The present invention is a method that puts the above-mentioned idea into practice, and this method will be explained with examples.

The warped lumber product is placed in a pressure vessel and heated under pressure using saturated steam.

In order to frequently change the saturated steam pressure between 0.2 and 3.0 kg/clump while releasing a part of the saturated steam inside the container to the outside of the container, high-pressure steam from the boiler is transferred to the pressure vessel. Injection is stopped when the pressure reaches 3.0 kg/, and starts when the pressure inside the container reaches 0.2 k9/. If the initial moisture content of the lumber product is around the fiber saturation point, the pressure inside the container must be varied frequently until the temperature inside the container reaches 100%.
After exceeding 00, the time is adjusted appropriately according to the difference in the initial moisture content based on the number of minutes calculated from the thickness of the wood. When pressurizing and heating a sawn timber product with saturated steam, as long as the temperature of the wood does not rise to the saturated steam temperature, if the saturated steam comes into contact with the sawn timber product, the temperature of the steam will drop and the steam will turn into streaks of water. Since the inside of the container is pressurized, the condensation water generated on the surface of the sawn timber product enters into the wood.

If the pressure inside the container is constant, as in the SV heating method, no fog water will be generated if the temperature of the wood surface approaches the steam temperature, so the amount of water fog that permeates into the wood will be small, and the water content will be too high. There will be no increase. Set the saturated vapor pressure to 0.2 to 3.0k9/
If you change the flow frequently between c flows, the pressure will change from 0.2 to 3.0k9 even when the flow is 0.2k9/lump because it is in a pressurized state.
When it is rising to ', it is a pressurized state under pressure, and when it is decreasing by 3.0 to 0.2 k9/c, it is a reduced pressure state under pressurization.

In a pressurized state under pressure, condensed water generated on the surface of the wood permeates into the wood due to the pressure applied, and as it permeates, the temperature of the condensed water decreases, and the low-temperature water and air contained within the wood from the beginning are removed from the wood. It moves towards the center of the wood due to pressure. When the pressure is reduced under pressure, boiling occurs near the surface of the wood, and the heat of vaporization required during boiling lowers the surface temperature of the wood, creating a base that increases the amount of water condensation generated during the next pressurization. During pressurization, the contained water and air that moved toward the center of the wood move toward the surface of the wood, and the air passes through the water content in the wood and exits the wood, and when the next pressurization is applied, the condensed water and air move into the wood. A place will be created for you to enter. The distortion that occurs during the drying process after sawing is due to uneven shrinkage caused by a partial decrease in moisture content. The air inside the wood is released from the curved part and then heated,
Fog water is injected to increase the temperature and expansion of the area and correct the distortion.

While the temperature inside the wood is not uniform, the saturated vapor pressure is reduced to 0.
By frequently varying the pressure over a medium and wide range of 2 to 3.0 k9', it is possible to achieve a large decompression state under pressure, and the temperature of the wood is increased too much by wasting the heat of vaporization due to boiling near the surface of the wood. If it is possible to increase the moisture content without causing any damage, and after the above-mentioned period of time has passed, the wood will be in a state immediately after sawing in which the distortion has been almost corrected, and the internal temperature of the wood will be close to about 110 oo. In addition, a sawn timber product with a large difference in moisture content distribution, such as moisture content unevenness that has been present since the time of tree standing, is placed in a pressure vessel, filled with saturated steam, and after the temperature inside the pressure vessel exceeds 100 qo, the thickness side of the sawn timber product is If the pressure of saturated steam is frequently varied between 0.3 and 0.5 k9' for a number of minutes, condensation water will mainly infiltrate into the parts of the sawn timber product that contain less water. As the moisture content increases, the internal temperature of the wood reaches approximately 10,800°C.

The above two kinds of sawn products heated to about 108 oo are heated at a saturated steam pressure of 0.8 to 1.2 kg/ground frequently for a number of minutes calculated by the thickness of the sawn products. If the pressure is varied, the pressurized state under increased pressure and the reduced pressure state under increased pressure are frequently repeated, and development that does not occur with fixed pressure application such as heating in the SV method can be achieved. A large amount of water is generated, and while the amount of striped water increases inside the wood, the water content moves from areas with more water to areas with less water, and the low-temperature water content that was in the lumber product during the reduced pressure state moves toward the surface layer. However, since the high-temperature condensed water moves toward the center under pressure, the two are mixed smoothly, and after the above period of time, the moisture content distribution becomes uniform and the inside of the sawn timber product becomes uniform. The temperature becomes a uniform temperature of 12000 as the temperature of the mixed old and new contained water increases. After that, if the saturated steam is released from the pressure vessel and the pressure inside the vessel is reduced,
Due to the uniform internal temperature of the sawn product, all water content boils uniformly.

If all the contained water is boiled uniformly, the movement of the contained water will be prevented by the boiling pressure during one depressurization, without having to repeat the process of steaming and depressurization in the SV method many times. All of the resin that had become stained is chemically decomposed and removed by steam distillation, and the enlarged development of thin capillaries and pores occurs, making the wood easy to release all the water contained, and at the same time, all the cell cavities are removed. Since the water contained therein boils uniformly, it is possible to produce a lumber product having cavities in which part of the water contained uniformly diffuses throughout the cell cavities. After making such lumber products, if you take the wood out of the pressure vessel and dry it naturally outside, there will be no areas where the contained water will diffuse unevenly, and there will be uniform cavities in all cell cavities. Therefore, there is a cavity in which the water contained in the cell cavity, which is difficult to move, can move to the adjacent tsumugi cavity, so simultaneous movement is possible for all the contained water to evaporate, and excess water gradient does not occur. First, since the cause of uneven moisture content distribution has been removed, the moisture content decreases uniformly, so there is no uneven shrinkage, and the material has an equilibrium moisture content, and no distortion occurs.

Next, using the method of the present invention, wood having uniform cavities in all cell cavities according to the above-mentioned example was made, and then dried using the natural drying or SV method. An example of a process that was processed using the conventional method without using the method is also shown.

1. If you make a knotless post angle of 4 pieces from a medium-grained log of high-quality cypress, the moisture content distribution between the periphery and the center of the log will be different from when it was standing, so if you leave it as it is, it will move in the direction of the line. Therefore, it can no longer be used as a pillar.

If we tried artificial drying of this column angle using the SV method or other existing methods, the warpage would become larger, so there was no other option than to gradually dry it naturally over a long period of time. 12 stored in warehouse
If we collect six pillar angles that curve about three degrees toward one corner in this pillar with an elevation angle of 0, and apply the processing method shown in the above example, this warpage will be completely eliminated. It was taken out of the pressure vessel as straight wood.

Since it has not yet become a dry material, put it into the pressure vessel again.
When the moisture content was reduced using the SV method over a day, the moisture content became 21 soil and 1%. When it was left in the warehouse for another week, the moisture content decreased to less than 18%, allowing it to be used in wooden houses. This example shows that even if the warpage becomes larger if the SV method is applied immediately, if the SV method is applied after the invention method of the present application is carried out, the warped material can be corrected and the material can be made into a dry material. ing.

2. When split wood is taken from a small-diameter raw log, the moisture content of the outer part of the wood is higher than that of the back part of the wood, so if left untreated, it will bend in the direction of the outer surface of the tree and become unusable.

Such split wood is not worth the cost of drying due to its low price, but even if you force it to dry using the SV method for 2 days or hot air drying for 5 days, you will not be able to obtain the dried wood of Naomura. For example, if you stock a 40 x 9 length warimura made of two pieces of small diameter pine wood, there will be a lot of warping and twisting.

After treating these strain-generating materials in accordance with the embodiments of the present invention, excluding the bent wood,
If left outdoors for 2 weeks, the moisture content will be 18% with all raw wood.
I was able to dispose of it. The conventional method of the present invention has been able to break through the common sense in the industry that it was not possible to make dry lumber even if thinned wood or small pine wood was cut into dry wood. This shows that the fixed concept of lumber varieties can be corrected by the

3. If a column corner is taken from thinned wood or small-diameter wood from a pine tree, it will not be possible to mill the wood so that the edges with a high moisture content are evenly placed outside the column corner, and the moisture content will be distributed on all four sides at the same location in the length direction. There will be a high part and a low part, and if left untreated, warping and twisting will occur in addition to cracking, limiting the places where it can be used, and S
With any of the conventional drying methods, including the V method, even if profitability is ignored, it is not possible to produce a desiccated material that can be sold.

I calculated the volume based on the unopened dimensions and purchased the thinned pine wood.
Cut 60cm long, 105mm elevation angle, 9mm elevation angle, 75cm
If lumber sawn to a willow angle and a 60m elevation angle is treated according to the embodiment of the present invention, dried naturally, connected with mini fingers and cut into regular lengths, it will not crack. It can be made into a long material without twisting or warping, and the yield is 120%.

Currently, afforestation businesses cannot be established unless production methods that utilize thinned wood and small-diameter trees are developed, but the invention of the present application allows for the creation of various new production methods such as the new method described above. It shows.

The present invention, as shown in the above embodiments and production examples, can reduce the pressure of saturated steam in a pressure vessel by reducing the pressure of saturated steam in a pressure vessel. By frequently changing the lumber, it expands due to the increase in water content in the lumber product, returning it to the state before distortion occurred.
In addition, after correcting uneven moisture content from the time of tree stand, etc., the pressure inside the container is reduced to create a wood with uniform cavities in which some of the water contained in the lumber has emanated from all cell cavities. Since this is a method to correct or prevent the occurrence of distortion by making it a lumber product that shrinks, it is possible to use materials that generate distortion, which could not be used until now, in the same way as general materials, and at the same time, it can be used as a material that generates distortion. This has great practical effects, as it enables the development of many new uses for wood, which was previously limited.

Claims (1)

[Claims] 1 Placing sawn timber products that are distorted or that are likely to become distorted in saturated steam in a pressure vessel, and by frequently varying the pressure of the saturated steam, each sawn timber product is The condensation water generated on the surface and inside is forced into each sawn product, expanding the warped sawn product to correct the distortion, and at the same time remove the warped sawn product or the risk of warping. After making the water content distribution and temperature distribution of a certain sawn timber product uniform, the saturated steam is released and the pressure inside the pressure vessel is reduced to uniformly boil all the water contained, and all of the water content is uniformly boiled. A method for correcting warped materials and preventing the occurrence of warping, which is characterized in that the wood has uniform hollow parts in which a portion of the water contained in the cell cavities has boiled off and is made into a sawn lumber product that will not experience uneven shrinkage thereafter. Method.