JPH02165902A - Recovering method for deformation of cell of wood material - Google Patents

Abstract

PURPOSE:To recover the deformation of cell of wood material with high energy efficiency by so treating with steam the wood material in which cells are deformed that enthalpy to be applied per unit weight of the wood material becomes the whole wetting heat or less of the wood material. CONSTITUTION:The deformation of cells of wood material occurs mainly in a drying step. In order to efficiently recover the deformation, enthalpy per unit weight of the material of steam in contact with the wood material is set to the whole wetting heat or less of the wood material. Thus, the interior and exterior of the wood material in contact with the steam all attain fiber saturation point or less. Since the wetting heat is generated, the steam has energy for wetting the cellular wall.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for restoring deformed cells of wood. More particularly, the present invention relates to a treatment method that can energy-efficiently and relatively effectively restore wood that has undergone cellular deformation.

[Prior art and its problems] Wood cells are originally cylindrical, but if the cells are deformed due to stress from the inside and outside, it will appear as abnormal shrinkage after drying, resulting in deformation of the wood and deterioration of dimensional stability. In order to deal with this phenomenon, attempts have been made to use steam steaming.

However, in all of the methods currently in use, the enthalpy of water vapor imparted to the wood per unit weight of wood is greater than the total wet heat of the wood, so the surface and interior of the wood reach above the fiber saturation point and the water vapor condenses into condensation. becomes. As a result, the wood tends to become saturated with water, requiring re-drying. In addition, tensile force is generated in the cell lumen during drying, which tends to cause similar cell deformation.Furthermore, the condensation heat given to the wood when water vapor condenses does not only unnecessarily increase the temperature of the wood and deteriorate the wood quality. This results in large energy loss.

[Problems to be Solved by the Invention] Therefore, in view of the above-mentioned prior art, the inventors of the present invention sought to find a method for recovering cell deformation caused in wood in an energy efficient and relatively effective manner (through intensive research). As a result of repeated efforts, they discovered for the first time a completely new method for restoring cell deformation of wood that can solve all of these problems, and completed the present invention.

[Means for Solving the Problem] That is, the present invention treats wood whose cells have been deformed with steam such that the enthalpy given per unit weight of the wood is less than the total wet heat of the wood, thereby deforming the cells. on how to recover.

[Operations and Examples] Deformation of wood cells is mainly caused during the drying process. That is, it is caused by transmitting a tensile force to the cell wall when free water existing in the inner cavity of wood cells is extracted. Therefore, it is necessary to maintain the wood below the fiber saturation point in order to efficiently deform the cells (as a condition for recovery ■).

2) Energy that causes water vapor to swell cell walls Luggy to have.

Is required. In order to provide the condition 1), it is sufficient that the enthalpy given per unit weight of the wood to the water vapor in contact with the wood is less than the total wet heat of the wood, and by this condition, all the inside and outside of the wood in contact with the water vapor are saturated with fibers. point or less. In addition, in order to provide the condition 2), the encruby given per unit weight of the wood to be treated should give the integral adsorption heat of the wood, but at this time, the heat of moisture is generated at the same time, so the condition 1) is satisfied. If water vapor satisfies the following conditions, the condition 2) can be satisfied.

Next, the method for recovering abnormal shrinkage based on cell deformation of wood according to the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example I and Comparative Example 1 Two specimens of white ash sapwood measuring 150mm in the fiber direction, 75III11 in the tangential direction, and 4++n in the radial direction were extracted from adjacent parts, and each was boiled in water for 5 hours at 70°C. The sample was dried for 72 hours in a constant temperature and humidity chamber (model IG-41, manufactured by Yamato Kagaku ■) set at 70% RH. After that, 60°C steam (Example 1) was applied to one specimen, and 100°C steam (Comparative Example 1) was applied to the other specimen for 1 hour, and each specimen was then heated to the above constant temperature. It was placed in a 70" C170% RHI and dried for 72 hours. The results are shown in Table 1.

[Margin below] Part 1 table Considering the above results, we get the following.

The total heat of wetting is the sum of the integral heat of adsorption up to the fiber saturation point and the heat of condensation of water at the adsorption temperature. 70℃, 70%RH
Since the equilibrium moisture content of wood is approximately lO%, the moisture content l
The integral heat of adsorption from O% to the fiber saturation point is (integral heat of adsorption) #70 cal/Kg and the heat of condensation of water at 70°C is (heat of condensation/70°C) 4559.1 Kcal/Kg
Therefore, the total wet heat is 70 + 559.1 = 629.1 (K
cal/g), and the enthalpy of water vapor at 60℃ and 100℃ is 622.9Kc, respectively.
g to al/, g to cal/ to 638.8
Water vapor at 100°C will cause condensation on wood. This problem is caused by the insufficient restoration of dimensions during the secondary drying shown in Table 1. Furthermore, the enthalpy of water vapor at 100°C is 9.7 Kcal, which is greater than the total wet heat.
/ Kg, and energy loss occurs by this amount of heat. As described above, abnormal contraction caused by cell deformation is effectively improved by this treatment, and a remarkable recovery ability is observed.

As mentioned above, the method of restoring wood deformation according to the present invention is energy efficient (it is the first treatment method that can relatively effectively restore cell deformation that has occurred in wood, and will reduce the added value that will occur as the quality of wood deteriorates in the future. We believe that this is a groundbreaking invention for improving.

Procedural amendment (formality) %formula% ■Display of incident 26 Name of invention 3. Person who makes corrections Relationship to the incident: Patent applicant Wood cell deformation recovery method 5. Subject of correction Column for the name of one invention in the specification 6. Contents of amendment Revised to ``Shape Restoration Method.''

Claims (1)

[Claims] A unit of wood in wood that has undergone cellular deformation. The enthalpy given per weight is Treated with steam that is less than the total wet heat of the material. A method for restoring cell deformities.