JP2001058304A - Method for drying wood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dry a wood with improved strength and good workability without diminishing its commodity value by compression-fabricating the wood at a plastic fabricating temperature to apply a slight compression deformation of the wood and next lowering the temperature to carry out the routine drying process of the wood. SOLUTION: A container 16 for compression is a stainless steel container for storing a plurality of cut pieces with a rectangular section of wood 15 and has numerous drainage holes 31 for draining moisture discharged from the wood 15 in the board thickness direction. In addition, between the cut pieces of the wood 15 in the vertical direction, three pieces of stainless steel partition and compression plate 27 having a little smaller width than the inner width(w) of the container 16, are arranged. Further, between the cut pieces of the wood 15 at each of the stages in the horizontal direction, five pieces of stainless steel partition and compressibility setting plate 29 having a little smaller height than the height of the wood 15 with a sectional width W, are arranged in the perpendicular direction. The wood 15 does not suffer from cracking during drying process because its shrinkage is restrained and the strength of the wood 15 is improved without deteriorating its commodity value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drying wood to prevent cracking of the wood.

[0002]

2. Description of the Related Art Conventionally, drying of cut and sawn lumber is usually performed by introducing pressure steam at 50 to 120 ° C. into wood placed in a drying vessel and depressurizing the wood in accordance with the water content of the wood. Further, as another drying treatment, pressure steam of 50 to 120 ° C. is introduced into wood placed in a drying container, and the temperature and humidity are controlled by wind power. Wood is shrunk by about 3 to 8% due to drying, and cracks are generated. Particularly, in the case of a core material, a large crack is generated due to a large difference in shrinkage between the core and the outside. In order to prevent the occurrence of cracks, the wood is previously split at one location in the length direction and then dried.

[0003]

However, in the conventional drying treatment of wood, in order to prevent cracks, the wood is split in advance, so that the commercial value is reduced and the splitting of the wood by the split is not only performed. There was a problem that the strength was reduced. In addition, there is a problem that the working process is lengthened due to the necessity of a processing work for splitting the back.

[0004] The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a method of drying wood which can improve strength and workability without lowering commercial value. .

[0005]

According to the present invention, there is provided a method for drying wood according to the present invention, which comprises compressing wood at a plastic working temperature to perform a slight compressive deformation, and then lowering the temperature to perform normal drying. It is configured to perform processing. by this,
During the drying process, the shrinkage of the wood is suppressed, so that cracks do not occur. In the method for drying wood according to the present invention, the heating of the wood to the plastic working temperature can also be performed using steam, a heater, hot air, or high frequency. Thus, an optimal heating method can be selected according to the situation. In the method for drying wood according to the present invention, the compression processing of the wood at the plastic working temperature may be performed by storing the wood in a tank. Thereby, compression processing and drying can be processed in the same tank.

In the method for drying wood according to the present invention, the compression processing of the wood at the plastic working temperature can also be performed by hot pressing. Thereby, heating and compression can be performed by the same device. In the method for drying wood according to the present invention, the light compressive deformation may be performed by compressing the wood in the thickness direction by 5 to 15%.
This allows the wood to be compressed appropriately. If the compression is less than 5%, the occurrence of cracks cannot be suppressed, and if the compression exceeds 15%, the compression means becomes excessively large and uneconomical. In the method for drying wood according to the present invention, the normal drying treatment of wood is performed by first putting wood into a tank and heating the wood to a temperature of 50 to 120 ° C using steam.
The step and the second step of removing the water content by reducing the pressure of the heated wood can be performed a plurality of times. Thereby, shrinkage due to drying can be reduced. When the heating temperature is lower than 50 ° C., the drying time becomes longer. On the other hand, when the heating temperature is higher than 120 ° C., the wood is discolored.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a configuration diagram of a wood drying apparatus to which the wood drying method according to one embodiment of the present invention is applied, and FIG. 2 is a sectional view of a main part of the wood drying apparatus. As shown in FIG. 1, a timber drying apparatus 10 to which a timber drying method according to an embodiment of the present invention is applied is disposed on a floor 11 via a mounting base 12, and can be opened and closed with a sealing lid (see FIG. 1). A tank 13 which is an example of a pressure vessel having a pressure vessel (not shown);
A wood transport cart 14 that can move inside and outside the tank 13 via a sealing lid, a compression container 16 that is mounted on the wood transport cart 14 and that can store a plurality of woods 15, and is stored in the compression container 16. A plurality of pieces of wood 15 are subjected to a plastic working temperature (about 170
(−180 ° C.). Hereinafter, these will be described in detail. In addition,
For the wood 15, cedar, cypress, pine, and the like, which are core materials, are used.

As shown in FIG. 1, the tank 13 is made of a steel plate or stainless steel and formed in a drum shape.
The outer periphery of the bottom portion is fixed to the floor surface 11 via a mounting base 12 having a rectangular shape in plan view. A pair of rails 18 on which the wood transport cart 14 travels are mounted via rail mounting brackets 19 in the longitudinal direction of the bottom in the tank 13. At the top of the tank 13, the wood 1 in the tank 13
5 is provided with a steam supply pipe 21 for heating the plastic processing temperature to a plastic working temperature or performing a drying process.
Is provided with an on-off valve 22. Further, the plastic working temperature of the wood 15 in the tank 13 is adjusted, or
A steam exhaust pipe 23 for reducing the pressure in the inside 3 is attached, and the steam exhaust pipe 23 is provided with an on-off valve 24.
A temperature detector (not shown) for detecting the plastic working temperature is attached to the tank 13.

The wood transport cart 14 includes a pair of rails 18 in the tank 13 and wheels 25 rolling on the pair of rails outside the tank 13 connected to the pair of rails 18, and a deceleration for driving the wheels 25. A drive means (not shown) having a machine, a drive motor, and the like, and a mounting frame 26 which holds the wheels 25 and the drive means and on which the compression container 16 can be mounted. Rail 18, rail mounting bracket 1
9 and the wood transporting cart 14 have strength enough to withstand the pressing force of the compression working means 17 and at the same time withstand the plastic working temperature.

As shown in FIG. 1 and FIG.
Reference numeral 6 denotes a steel plate or stainless steel container for storing a plurality of pieces of wood 15 cut into a rectangular cross section.
Drain hole 31 for draining water released from wood 15
(Having a hole diameter of about 1 mm). In the compression container 16, six pieces of wood 15 are stacked and stored in four stages. Between the woods 15 in the up-down direction, three partition plates and compression plates 27 made of steel plate or stainless steel having a width slightly shorter than the inner width w of the compression container 16 are arranged. In the thickness direction of the partition / compression plate 27, a drain hole 28 (having a diameter of 1 m) for draining water released from the wood 15 is provided.
m) are formed in large numbers.

The height h, which is slightly lower than the height H of the wood 15 having a cross-sectional width W, is provided between the horizontal woods 15 of each stage.
5, five partition / compression ratio setting plates 29 made of steel plate or stainless steel are arranged in the vertical direction. Similarly to the partition and compression plate 27, the partition and compression ratio setting plate 29 is formed with a large number of drain holes 30 (having a diameter of about 1 mm) for draining water released from the wood 15 in the plate thickness direction. . The diameters of the drainage holes 28, 30, and 31 are set to such a size that the molds of the drainage holes 28, 30, and 31 are not formed on the surface of the wood 15 by compression.

The compression means 17 is a steel plate or stainless steel compression plate 3 placed on the uppermost timber 15.
2, a pressure block 33 made of stainless steel for pressing the compression plate 32, and a hydraulic cylinder 35 which is an example of a driving means for driving the pressure block 33 in the vertical direction via a connection fitting 34 made of stainless steel. I have. Hydraulic cylinder 35
The head side is attached by a pin 37 to a central portion of a horizontal compression member 36 horizontally disposed at the upper end of the vertical compression members 20 and 20 a provided vertically on both sides of the mounting base 12. At a portion where the rod 38 of the hydraulic cylinder 35 penetrates the tank 13, a seal block 39 fixed to the tank 13 and a packing 40 are provided within the seal block 39. A pressure block 33 is attached via 34. The pressure block 33 and the compression plate 32 are also provided with a large number of drain holes in the plate thickness direction, similarly to the partition and compression plate 27.

By providing the compression vertical members 20 and 20a and the compression horizontal member 36, the reaction force of the pressing force by the hydraulic cylinder 35 can be borne.
No. 3 is not required to be affected by the pressurizing force, and only needs to have strength enough to withstand the vapor pressure. In addition, the compression processing means 17
Plural units are provided according to the length of the wood 15 and the magnitude of the pressing force. The degree of slight compression deformation is to compress the wood 15 by 5 to 15% in the thickness direction. That is, as shown in FIG. 2, if the width W is constant, H / h = 1.05
1.15.

Next, a method for drying wood according to an embodiment of the present invention using the wood drying apparatus 10 will be described with reference to the drawings. (1) A compression container 16 is mounted on a wood transport cart 14 stopped outside the tank 13, and as shown in FIG. 1, a partition / compression plate 27 and a partition / compression ratio setting are set in the compression container 16. Timber 15 is stacked using the plate 29, and the topmost timber 1
The compression plate 32 is placed on 5. (2) After carrying the wood transport cart 14 into the tank 13, the tank 13 is sealed, the on-off valve 24 is closed, and the on-off valve 22 is opened, and saturated steam at 200 ° C. and 7 to 8 kgf / cm ² is supplied into the tank 13. To make the wood 15 a plasticizing temperature (or a plastic working temperature).

(3) It is confirmed by a temperature detector that the wood 15 has reached the plasticizing temperature, and the compression processing means 17 is operated to slightly compress the wood 15 as shown in FIG. h = 1.05-1.15) for about 20-30 minutes. (4) Thereafter, the temperature of the wood 15 is lowered to perform a normal drying process. First, the on-off valve 24 is opened to discharge high-temperature (about 170 ° C.) steam from the tank 13, and then the on-off valve 2 is opened.
4 is closed, the on-off valve 22 is opened, steam at 70 to 140 ° C. is put into the tank 13, and the wood 15 is heated to a temperature of 50 to 120 ° C. (first step of drying).

(5) Next, the on-off valve 22 is closed, the opening degree of the on-off valve 24 is adjusted, the steam in the tank 13 is released from the on-off valve 24 to reduce the pressure, and 50 to 120 in the first step of drying.
The water inside the wood 15 heated to the temperature of ° C. is removed (second step of drying). (6) The steps (4) and (5) are repeated a plurality of times until a predetermined dry state is obtained. (7) When the drying process is completed, the wood transport cart 14 is carried out of the tank 13, and the dried wood 15, the partition / compression plate 27, the partition / compression ratio setting plate 29, and the compression plate 32 are removed from the compression container 16. Take out.

In the method for drying wood according to one embodiment of the present invention, the wood 15 is compressed at a plastic working temperature, so that the compression does not return to the original state even if the temperature is lowered and dried. Therefore, even if the wood 15 is dried, the occurrence of cracks due to the difference in shrinkage can be prevented. Moreover, since the wood 15 is compressed, the strength of the wood 15 is increased, and as a result, the wood 15 can be used as a strength member such as a base or a pillar. Further, since heating and drying can be performed in the tank 13, workability is improved.

In the present embodiment, the method of heating the wood 15 to the plastic working temperature is performed by using the heating steam, but is not limited thereto, and the wood 15 is heated by using a heater, hot air, high frequency, or another method. You can also. Wood 1 at plastic working temperature
Although the compression processing of No. 5 was performed by storing the wood 15 in the tank 13, the compression processing is not limited to this as long as the plastic processing temperature can be maintained. For example, the wood can be heated to a plastic working temperature, and the wood heated to the plastic working temperature can be heated by a compressible hot press.

Although the degree of the slight compression deformation is such that the wood 15 is compressed by 5 to 15% in the thickness direction, the wood 15 can be compressed outside this range if necessary. As the compression ratio increases, the strength increases, but the compression processing means becomes excessive. The magnitude of the compression is mechanically adjusted by the height (corresponding to h) of the partition / compression ratio setting plate 29, but is not limited to this. For example, the compression processing means may be provided with a pressing force detector. It can also be adjusted. The drying process of the wood 15 includes a first drying process in which the wood 15 is placed in the tank 13 and heated using steam, and a second drying process in which the heated wood 15 is depressurized to remove moisture therein. It was done by repeating the number of times, but it is not limited to this,
Drying can also be performed by other existing methods.

The heating and drying of the wood 15 are performed in one tank 1
3, the heating and drying treatment was carried out in the tank 13
May be provided separately to form a double tank type, and the tank 13 may be heated and dried indirectly from outside using heated steam or the like. As an example of wood compression, W
It is possible to compress W × h (unit: mm) to 120 × 120 or to convert 130 × 240 to 120 × 240 by compressing one having × H (unit: mm) of 120 × 130. As compression processing means 17, together with wood 15
Although the lumber transport cart 14 is also configured to be compressed, the lumber 1 in the compression container 16 is compressed without compressing the lumber transport cart 14.
It is also possible for only 5 to have an economical structure, for example to be compressed using a screw mechanism.

[0021]

In the method for drying wood according to the first to sixth aspects of the present invention, shrinkage of the wood is suppressed during the drying treatment so that cracks do not occur. Improvement can be achieved. In particular, in the method for drying wood according to the second aspect, the heating method can be selected according to the circumstances, so that the optimum method can be freely selected according to the type of wood, the method of treatment, and the like. In the method for drying wood according to the third aspect, since the compression processing and the drying can be performed in the same tank, workability is improved.

In the method for drying wood according to the fourth aspect, since heating and compression can be performed by the same apparatus, workability is improved and an inexpensive apparatus can be obtained. In the method for drying wood according to claim 5,
Since the wood can be compressed appropriately, cracking is suppressed and at the same time, the compression processing means is appropriate and economical. In the method for drying wood according to the sixth aspect, since shrinkage due to drying can be reduced, the occurrence of cracks can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wood drying apparatus to which a wood drying method according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view of a main part of the wood drying apparatus.

[Explanation of symbols]

10: Wood drying device, 11: Floor surface, 12: Mounting stand, 13: Tank (pressure vessel), 14: Wood transport trolley,
15: wood, 16: container for compression, 17: compression processing means,
18: rail, 19: rail mounting bracket, 20,
20a: Vertical material for compression, 21: Steam supply pipe, 22: On-off valve, 23: Steam exhaust pipe, 24: On-off valve, 25: Wheel, 2
6: mounting frame, 27: partition and compression plate, 28: drain hole, 29: partition and compression ratio setting plate, 30: drain hole,
31: drain hole, 32: compression plate, 33: pressure block,
34: Connection fitting, 35: Hydraulic cylinder (drive means),
36: Horizontal material for compression, 37: Pin, 38: Rod, 3
9: seal block, 40: packing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2B230 AA16 AA27 BA01 BA02 BA17 EA19 EB05 EB06 EB12 EB13 EB28 EB29 EC02 EC13 EC24 3L113 AA01 AB02 AB09 AC05 AC23 AC43 AC45 AC46 AC48 AC49 AC54 AC57 AC63 AC67 AC72 AC73 AC75 AC90 BA05 CA08 DA01 DA06 DA07 DA21 DA24

Claims (6)

[Claims] 1. A method for drying wood, comprising subjecting wood to compression working at a plastic working temperature to perform a slight compression deformation, and then lowering the temperature to perform a normal drying process. 2. The method for drying wood according to claim 1, wherein the heating of the wood to the plastic working temperature is performed using steam, a heater, hot air, or high frequency. 3. The method for drying wood according to claim 1, wherein the compression processing of the wood at the plastic working temperature is performed by:
A method for drying wood, wherein the wood is stored in a tank. 4. The method for drying wood according to claim 1 or 2, wherein the compression processing of the wood at the plastic working temperature comprises:
A method for drying wood, which is performed by hot pressing. 5. The method for drying wood according to claim 1, wherein the slight compressive deformation is performed by compressing the wood in a thickness direction by 5 to 15%. How to dry wood. 6. The method for drying wood according to any one of claims 1 to 5, wherein the normal drying of the wood is performed by:
Put the wood in a tank and use steam to reach 50-120 ° C.
A method of drying wood by repeating a plurality of times of a first step of heating the wood and a second step of removing the inside water by reducing the pressure of the heated wood.