JP2002052510A - Drying of wood by dehydration by centrifugal force and forming of hard faced layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an artificially drying method for raising a use value as a structure material by raising a surface hardness of a cedar material considered to have only a strength of 75% compared with that of an imported material (an Oregon pine) as a pure material in order to propagate domestic materials having a tendency of being pressed down by imported materials of a low cost while generation of inferior goods is solved by shortening a period to be taken for initial drying artificial drying which are required for manufacturing dry wood and suppressing sudden drying of a surface layer part becoming causes for occurrence of a crack, a stress and the like. SOLUTION: After carrying out dehydration treatment of free water contained in wood by utilizing a centrifugal force as a means for hastening an initial drying stage of wood and dynamically moving the wood, a surfaces is pressed by an iron plate at a high temperature, a carbonized and compacted layer is formed in a surface layer part, and suppression of surface drying becoming a cause for a crack, improvement of shape stability and increase of strength are achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to stabilization of shape and improvement of strength by drying and surface treatment of wood.

[0002]

2. Description of the Related Art Conventionally, artificial drying of wood is based on vapor-phase drying using a steam system or a dehumidifying system.
The method of drying while adjusting the temperature and humidity in the room was the mainstream. However, drying of the surface layer progresses rapidly, but drying of the inside is due to factors such as a decrease in thermal conductivity and closing of the cell wall.
The drying rate was slow, and these were the major factors prolonging the drying period. Further, it has been considered that cracks, warpage, distortion, and the like are caused by a difference in pressure and a difference in shrinkage due to a difference in moisture content between the surface layer and the inside, and it is difficult to generate defective products and unify quality.

In order to solve these problems, a method has recently been used in which a small diameter material is dried in a short time, and then the laminated material (laminated material) is used to improve the material strength and stabilize the quality. However, there are also major issues such as higher costs.

[0004]

SUMMARY OF THE INVENTION According to the present invention, the period of initial drying and artificial drying required for producing dry wood is shortened, and the surface layer which causes cracks and distortions is reduced. The occurrence of defective products is eliminated by suppressing rapid drying. In addition, in order to spread the domestic timber that seems to be cheap imported wood, by increasing the surface hardness of cedar wood that is only 75% stronger than imported wood (Yonematsu) as solid wood, An object of the present invention is to provide an artificial drying method that enhances the value of use as a structural material.

[0005]

According to the present invention, centrifugal force is used as a means for accelerating the initial drying stage of wood, and dehydration of free water contained in the wood is performed by dynamically moving the wood. Thereafter, the surface is pressed with a high-temperature iron plate to form a carbonized / consolidated layer on the surface layer, thereby suppressing surface drying which causes cracking, improving shape stability and improving strength.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Water contained in wood is mainly divided into free water and bound water, and it is said that each of them exists at a ratio of 7: 3 when the water content is 100%. As the raw material dries, first free water and then bound water are lost. Therefore, when the water content is less than 30%, cracks and irregularities begin to occur due to differences in shrinkage and pressure. The purpose of the centrifugal drying apparatus is mainly to dehydrate the free water, and the inside of the apparatus is heated using steam or the like to activate the free water in order to increase the dehydration efficiency.

Next, hemicellulose and lignin, which are the main components of wood, begin to thermally decompose at around 100 degrees and 200 degrees, respectively. Since these substances play a role like a reinforcing bar in forming wood, the shape stability of wood can be achieved by softening and reforming these components. However, Japanese cedar, which is the main source of timber,
Even when dried as it is, it is said that it is only 75% stronger than Yonematsu. Therefore, by heating and compressing the surface of the wood, the fiber density of the surface layer portion of the wood is increased, and the inside moisture is prevented from being dried on the surface. By doing so, it is possible to suppress the pressure difference from the inside due to rapid drying of the surface and artificially create the same state as natural drying with the bark attached. In addition, as the surface density increases, the surface hardness increases and the water retention ability decreases, so that shrinkage causing cracking and warpage is eliminated, and the shape can be stabilized.

[0008]

Embodiment 1 FIG. 1 is a plan view of a lathe part of a centrifugal force device. The lathe is divided into nine sectors, each having an independent drying chamber. The wood that has been fixed and shallowly stacked with a special jig there is fixed on the lathe body along the rails using the stopper at the center of the lathe while keeping the trolley. After securing the trucks to all sectors, close the entrance door and rotate the lathe. Moisture scattered from the timber port flows out through a groove dug in the wall, and is discharged to the outside through a drain pipe provided on the floor in the trolley. In the dryer room, the temperature and humidity of the room are adjusted while feeding steam from 12 in FIG. 2 to increase the temperature of the wood and activate the movement of moisture. Wood is centrifuged for 8 to 48 hours in a centrifugal machine to obtain a water content of 8%.
It becomes uniform within 0-50%.

[0009]

Example 2 After the wood whose moisture content was made uniform by the centrifugal force device was installed at the center of the compression press machine of FIG.
While spraying steam, the surface is uniformly compressed from both sides with a hot plate whose surface has been treated such as Teflon (registered trademark) processing so that the wood does not stick. Approximately 3 if the pillar is about 120
Shrink about 2 to 4 mm in about 4 tons and maintain that state for a few minutes. Although the set temperature of the iron plate differs depending on the finishing method, if only the shape stability is required, the temperature is set before or after the thermal decomposition temperature of lignin. However, the holding time in the state where the compression is applied is lengthened accordingly. When adding strength,
The temperature is set higher than the cellulose thermal decomposition temperature. At this time, in order to form a carbonized layer on the surface layer of the material, the finish is taken into consideration,
It is necessary to make the lumber with a size of about mm larger. Although wood can withstand temperatures up to about 300 degrees, flammable gases may be evolved when the surface temperature of the steel plate is increased. However, a large timber, such as a column or a beam, has a large heat capacity, so that the heat is diffused throughout, and the temperature rise is slow, and the generation of combustible gas is slowed accordingly. Even if a thick material is ignited, the progress of combustion can be suppressed because a carbonized layer is formed on the surface.

Next, the material is turned over and the same operation is performed. By doing so, a consolidated layer is formed on the four surfaces of the wood excluding the connection. The surface of this consolidated layer is finished using a sander or a planar.

[0011]

The reinforced wood thus produced retains sufficient dimensional stability even if the internal water content is high, and its strength is increased, so that quality control can be performed without being affected by the water content.

[Brief description of the drawings]

Fig. 1 Lathe top view for centrifugal dryer

Fig. 2 Cross section of centrifugal dryer

FIG. 3 is a plan view of a consolidation device.

FIG. 4 is a front view of a consolidation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Truck 2 Wood 3 Rail 4 Stopper for fixing wood 5 Centrifugal force device main shaft 6 Steam feeding pipe 7 Truck fixing jig 8 Free water drain pipe 9 Drain tank 10 Power engine 11 Centrifugal dryer support board 12 Steam inlet 13 Centrifugal machine lathe body 14 Compression iron plate 15 Teflon machined surface 16 Hydraulic jack 17 Steam water tank 18 Consolidation device support board 19 Connection fixed plate 20 Crane

Claims (5)

[Claims] 1. A lathe or a dryer rotates around a main shaft,
A device that uses the centrifugal force to dehydrate or dry wood. 2. A drying chamber for carrying wood in which a plurality of drying chambers are arranged in a circular shape and which can be rotated as a whole. 3. A drying apparatus which has a trolley which can fix wood by using a jig having a shallow pile or a shelf shape, and which can be fixedly mounted in a drying room as it is. 4. An apparatus for forming a hardened layer by consolidating and carbonizing a wood surface. 5. A wood drying apparatus having the features of claim 1 and claim 4.