JP3092966B2 - Wood drying method and drying equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for drying wood.

[0002]

2. Description of the Related Art In general, wood is easy to process, has good electrical and thermal insulation properties, and is superior as various materials. However, since wood is distorted due to contraction and expansion due to moisture absorption and desorption, it must be used before use. Need to dry.

[0003] Wood is also bleached, colored, preservative, insect repellent,
When performing chemical processing such as termite control, flame retardation, and resin impregnation, or chemical modification, it is necessary to dry before processing in order to improve the processing effect and efficiency.

[0004] For drying wood, natural drying in which wood is dried under natural conditions, dehumidification drying in which wood is placed in a drying chamber and dried using a dehumidifier, or a high-frequency heating device under reduced pressure is used. There is artificial drying such as reduced-pressure high-frequency drying that utilizes drying.

[0005]

However, the former natural drying can be relatively easily dried to a certain extent, but further drying takes a very long time (several months). On the other hand, the latter artificial drying does not require as much time as natural drying, but still takes a considerable amount of time (2 to 3 weeks).
In addition, during that time, the dehumidifier, the high-frequency heating device, etc. must be operated day and night, so that running costs, personnel costs, management costs, etc. are increased and the costs are high. In addition, since the inner core part contains more moisture than the outer sap part, only the sap part dries rapidly and the drying of the core part is delayed. There is also a problem that stress and compressive stress are generated in the core material portion, and many cracks occur.

The present invention has been proposed in view of the above points, and has as its object to provide a method and an apparatus for drying wood, which significantly reduce the drying time and prevent cracks during drying. Aim.

[0007]

According to the present invention, in order to achieve the above object, wood is heated by a suitable heating means in a processing vessel to soften the wood, and the wood is compressed by a suitable compression means to reduce the wood content. After forcibly squeezing out the water in the cavity, the compressed state of the wood is released to restore the wood to a slightly compressed state from before the compression, and the wood is dried by an appropriate heating means inside or outside the processing vessel. The present invention provides a method for drying wood.

Further, the present invention provides a processing vessel provided with an appropriate heating means for heating wood, a softening wood provided inside the processing vessel, for compressing the softened wood, and after the compression, the wood is more compressed. A press machine configured to release the compression of the wood so that the wood is restored to a slightly compressed state, wherein the wood is heated by an appropriate heating means to soften the wood in the processing vessel, and the wood is pressed by the press machine. After the compression, the water in the lumen of the wood is forcibly squeezed out, and then the compressed state of the wood is released by the press machine to restore the wood to a slightly compressed state from before the compression. The present invention provides a wood drying apparatus in which wood restored to a folded state is dried inside or outside the processing container.

[0009]

According to the present invention, the wood is heated and softened in the processing vessel, and the wood is compressed by an appropriate compression means to forcibly squeeze out the moisture contained in the wood. Accordingly, since the wood is dried in a state where the water contained in the wood lumen contained in the wood is forcibly squeezed out, the drying time can be greatly reduced. In addition, the growth strain of the wood is extracted by heating, and the moisture in the sapwood part and the core material part is almost squeezed out by compression, and the moisture content is made uniform,
No cracking during drying.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.

1 and 2 are schematic general views showing an example of an apparatus for carrying out the method of the present invention, wherein 1 is wood, 2 is a processing container capable of withstanding high temperature and high pressure, and 3 is a press machine. I have.

The processing container 2 has a lid 5 hermetically attached to an opening of a container main body 4 made of high-strength steel or stainless steel so as to be opened and closed. The processing vessel 2 is heated to a high temperature (1) through a steam supply pipe 6 from a steam supply device (not shown).
00 to 180 ° C) and high pressure (1.2 to 25 kg / c)
m ² ) is supplied, and the steam and the drain are recovered by the steam supply device through the steam drain pipe 7. Reference numeral 8 denotes an intake pipe connected to a vacuum device (not shown). The vacuum device draws air inside the processing vessel 2 through the intake pipe 8 so that the pressure inside the processing vessel 2 is reduced. I have.

As shown in FIGS. 1 and 2, the press machine 3 has a receiving mold 1 having a groove 9 for accommodating wood 1 and having a concave cross section.
0 and a plunger 12 vertically moved up and down by a plurality of press cylinders 11, 11... The press machine 3 lowers the plunger 12 by the press cylinders 11, 11, and fits the plunger 12 into the groove 9 of the receiving die 10.
Wood 1 stored in the groove 9 of the press cylinder 11,1
Compression is performed through the plunger 12 with the pressing force of 1..

The press machine 3 has a receiving mold 10 and a plunger 12 serving as high-frequency electrodes, and the wood 1 is sandwiched between the receiving mold 10 and the plunger 12.
By supplying a high-frequency current to the plunger 12 and the plunger 12, the high-frequency current is passed through the wood 1 so that the wood 1 is heated at a high frequency.

Next, a method for drying wood in the present invention will be described.

First, the wood 5 is carried into the processing vessel 2 by opening the lid 5 of the processing vessel 2, and the wood 1 is stored in the groove 9 of the receiving mold 10 of the press 3 as shown in FIG.

Next, after the lid 5 of the processing container 2 is closed and the processing container 2 is hermetically sealed, the inside of the processing container 2 is passed through a steam supply pipe 6 from a steam supply device at a high temperature (100 to 180 ° C.).
In addition, high-pressure (1.2 to 25 kg / cm ² ) steam is supplied, and the wood 1 is heated by the high-temperature and high-pressure steam.
In this state, when the wood 1 is heated for a predetermined time (1 to 10 minutes), the wood 1 absorbs high-temperature and high-pressure steam and is softened by a rise in temperature.

When the wood 1 is softened, the pressing machine 3
The plunger 12 is lowered by the press cylinders 11, 11,... And fitted into the grooves 9 of the receiving mold 10, and the wood 1 stored in the grooves 9 of the receiving mold 10, as shown in FIG. Plunger 12 with pressure of 11 ...
And compress it to about 1/2 to 1/3 in cross-sectional area ratio. By compressing the wood 1 in this manner, the pits inside the wood 1 are forcibly destroyed and there is no obstacle to the flow of moisture, the moisture of the wood 1 is almost squeezed out, and the moisture percentage of each part is reduced. The state becomes uniform.

After the wood 1 is compressed by the press 3, the plunger 12 of the press 3 is pressed by the press cylinders 11, 11,.
It rises to about 8%. Then, the wood 1 is released from the compressed state by the plunger 12 and gradually expands. As shown in FIG. 4, when the wood 1 is restored to about 98% of the thickness before compression, the wood 1 is pressed again to the plunger 12. As a result, it is slightly compressed from before compression. However, the wood 1 compressed by the press 3 is about 98% of the thickness before compression.
In order to restore to the front and back, after the wood 1 is compressed by the press machine 3 to squeeze out moisture, the plunger 12 of the press machine 3 is immediately raised by the press cylinders 11, 11 to release the compressed state of the wood 1. There is a need. If the wood 1 is kept in a high-temperature and high-pressure steam atmosphere for a long time while being compressed by the press machine 3, the wood 1 is fixed by the high-temperature and high-pressure steam, and the compressed state of the wood 1 is reduced. This is because the wood 1 is not restored even if it is opened.

Next, in a state where the wood 1 is slightly compressed from before compression, the inside of the processing vessel 2 is depressurized through the suction pipe 8 by a vacuum device, and the water vapor in the processing vessel 2 and the water squeezed out of the wood 1 are reduced. Is collected in the steam supply device through the steam drain discharge pipe 7, whereby the processing vessel 2 is recovered.
Is made to be in a state where the wood 1 can be easily dried.

In this state, the receiving mold 1 of the press 3
The wood 1 is dried to a predetermined state by heating the wood 1 by applying a high-frequency current to the plunger 12 and the plunger 12.

Thereafter, when the wood 1 is dried to a predetermined state, the lid 2 of the processing container 2 is opened to open the processing container 2, and the wood 1 is taken out of the processing container 2 to complete the drying of the wood 1. I do.

As described above, the wood 1 is heated and softened by the high-temperature and high-pressure steam in the processing vessel 2 and is compressed by the press 3 to forcibly squeeze out the moisture in the wood 1.
The wood 1 is restored to about 98% of the thickness before compression, and high-frequency current is supplied to the receiving mold 10 and the plunger 12 of the press machine 3 to dry the wood 1 by high-frequency heating. It can be dried in a predetermined state in half a day.

In the above embodiment, the wood 1 is placed in the processing vessel 2
The case where the water is forcibly squeezed out by compressing the inside of the inside and then drying in a predetermined state by high-frequency heating in the processing container 2 is described, but the present invention is not limited to this. It is also possible to take out the wood 1 from the processing container 2 and dry it to a predetermined state with an ordinary dryer after the water is forcibly squeezed out by compressing the water in the processing container 2. In this case, the wood 1 can be dried to a predetermined state within one day.

In the above embodiment, the wood 1 is softened by heating with high-temperature and high-pressure steam. However, it is also possible to heat the wood 1 with heating means other than high-temperature and high-pressure steam, for example, by heating with high frequency. It is. According to the high-frequency heating, since the wood 1 is heated from the inside, uniform heating is possible.

Further, in the above-described embodiment, the case where the timber is dried is described. However, as shown in FIGS. 5 to 7, if the receiving die 10 and the plunger 12 of the press machine 3 are changed, the log can be tapped. Can be dried. Also, by appropriately changing the receiving mold 10 and the plunger 12 of the press machine 3, it is possible to dry wood of various shapes.

[0027]

According to the present invention, as described above,
In drying the wood to a predetermined state, the wood is heated and softened by a suitable heating means in a processing vessel, and the wood is compressed by a suitable compression means to forcibly squeeze out the moisture in the wood lumen. Since the drying is performed by an appropriate drying means, the drying time of the wood is significantly shortened within half a day to one day, and the drying cost is greatly reduced. In addition, the growth strain of the wood is extracted by heating, and at the same time, the moisture in the sapwood part and the core material part is almost squeezed out by compression, and the moisture content of each part is made uniform. it can. In addition, the pits inside the wood are forcibly broken by heating and compression, so that there is no obstacle that obstructs the flow of moisture, so that the impregnation with resin, preservative, and the like becomes easy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus for performing a method of the present invention.

FIG. 2 is a longitudinal sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view showing a state in which wood is compressed by a press according to the method of the present invention.

FIG. 4 is a longitudinal sectional view showing a state in which wood is compressed to a slightly short thickness before compression after being compressed by the method of the present invention.

FIGS. 5 to 7 are views showing an operation state when a log is dried by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wood 2 Processing container 3 Press machine 4 Container main body 5 Lid 6 Steam supply pipe 7 Steam drain discharge pipe 8 Intake piping 9 Groove 10 Receiving mold 11 Press cylinder 12 Plunger

Claims (4)

(57) [Claims] 1. Wood is heated and softened by a suitable heating means in a processing vessel, and the wood is compressed by a suitable compression means to forcibly squeeze out the moisture in the wood cavity. Wherein the wood is restored to a slightly compressed state from before compression and dried by a suitable heating means inside or outside the processing container. 2. The method for drying wood according to claim 1, wherein the wood is softened by heating with high-temperature and high-pressure steam. 3. The method for drying wood according to claim 1, wherein the wood is heated by high frequency to be softened. 4. A processing vessel provided with an appropriate heating means for heating the wood, and provided inside the processing vessel, wherein the softened wood is compressed, and after the compression, the wood is slightly compressed from before the compression. A press machine configured to release the compression of the wood so as to restore to the state, wherein the wood is heated and softened by an appropriate heating means in the processing vessel, and the wood is compressed by the press machine. After forcibly squeezing out the water in the lumber of the wood, the compressed state of the wood is released by the press machine to restore the wood to a slightly compressed state from before compression, and to a slightly compressed state from before compression. An apparatus for drying wood, wherein the dried wood is dried inside or outside the processing container.