JPH1163823A - Method for drying wood and wood drying device used in the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for drying wood with high efficiency to sufficiently dry the wood to a core part in a short time. SOLUTION: In a method for drying wood 2, hot blast is blown and dried against the wood 2 at 80 to 150 deg.C and at a velocity of air of 0.1 to 1 m/sec through the air outlet of a duct arranged at the inner upper part of a drier. In this case, the two end parts of the wood 2 are covered with a cylinder body 1. In a wood drying device, a duct provided at an internal part with a plurality of fans and an air outlet is arraigned at the inner upper part of a drying chamber. The fans are disposed alternately in a reverse direction, a heating source is arranged in the vicinity of the air outlet, and a control means to regulate the temperature and the velocity of flow of hot blast is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a pillar, a base, a tension,
The present invention relates to a method for drying wood used for building structural materials such as digits and a wood drying apparatus used for the method.

[0002]

2. Description of the Related Art Conventionally, wood used as a building structural material must be sufficiently dried after felling, but in order to shorten the drying period, it is usually forcedly dried using a dryer. It takes about 600 to 700 hours (25 minutes) to dry the wood core sufficiently using a conventional dryer.
It takes up to 30 days), which requires enormous expenses when the depreciation cost of equipment such as drying facilities and other drying costs are combined.

[0003]

As a result of studying the shortening of the number of days for drying wood using a dryer, the present inventor has found that a conventional dryer uses hot air at 80 to 150 ° C. and a wind speed of 1.5 to 3 m / hour.
Since the wood is sprayed in sec, the sides and both ends of the wood (hereinafter referred to as "edges") dry rapidly, lowering the moisture content of those surface layers. However, the decrease in the water content deteriorates the heat conduction to the interior of the wood, and as a result, the surface of the wood hardens in a state where moisture remains therein, and it takes time to dry the interior of the wood. In the drying of wood, it was found that the moisture easily moves along the grain of wood, and that the diffusion of water from the edge of the wood is larger than that of the side of the wood. It was clarified that the internal drying time could be greatly reduced by reducing the difference in thermal conductivity between the inner and inner portions. Therefore, an object of the present invention is to provide an efficient method for drying wood, which can sufficiently dry the core portion in a short time, and a wood drying apparatus used for the method.

[0004]

In the method for drying wood according to the present invention, the wood is blown from the outlet of a duct provided in the upper part of the drying chamber.
Hot air of 80 to 150 ° C is blown onto the wood at a wind speed of 0.1 to 1 m / sec to dry it. Further, both ends of the wood placed in the drying chamber are dried by covering the end surfaces with a cylindrical body. This cylindrical body is preferably formed of a material having water absorbency and low thermal conductivity. The drying device of the present invention includes a duct having a plurality of fans and an outlet inside the upper portion of the drying chamber, and these fans are arranged alternately in opposite directions.
A heating source is provided near the outlet, and control means for adjusting the temperature and speed of the hot air is provided.

[0005] In the method for drying wood of the present invention, by placing the wood whose both ends are covered with a cylindrical body under a hot wind having a wind speed of 0.1 to 1 m / sec, the small edge of the wood is not directly exposed to the hot wind.
The moist state is maintained during drying, and the surface hardening due to rapid drying from the forehead can be delayed. As a result, the heat conduction to the interior of the wood is improved, and the moisture in the core of the wood can be gently diffused from the forehead over a long period of time, so that the drying time can be reduced and the wood can be dried uniformly.

The cylindrical body is formed in a square shape, a round shape, or the like according to the cross-sectional shape of the wood so as to cover the small edge of the wood. In addition, it is necessary to provide a gap between the wood and the cylindrical body, and this gap depends on the size of the applied wood. For example, in the case of a square bar having an end surface of 110 × 110 mm, the gap is 1 mm.
It is good to be about 10 mm, preferably 2 to 6 mm. The length of the cylinder is 150 to 250 mm, preferably about 200 mm, and the cylinder covers the wood from its end by about 50 to 100 mm,
The edge of the wood is preferably located approximately 100-150 mm deep from the open end of the cylinder. Further, the cylindrical body is preferably formed of a material having a low thermal conductivity with water absorption, and in particular,
Wood such as cedar is good.

[0007] The drying method of the present invention, which covers the edges at both ends of the wood placed in the drying chamber, is based on the ruling that hot air at 80 to 150 ° C is applied to the wood in the dryer at a wind speed of 1.5 to 3 m / sec. Although the conventional method is effective, the hot air in the above range is blown at a wind speed of 0.1 to 1 m / sec, preferably 0.3 to 0.5 m / sec.
By drying the wood placed in the drying chamber, a further effect can be obtained.

That is, when hot air having a wind speed of 1 m / sec or less is blown between the wood pieces placed in the drying chamber, the wood pieces move slowly from the core to the surface at a speed of about 10 mm per hour. Releases moisture. For this reason, surface hardening due to rapid drying of the wood is prevented, and a good-quality, soft-dried wood without damaging the wood and without cracking or twisting can be obtained.

As a drying apparatus used in the drying method of the present invention, for example, a duct is provided on the top surface of a drying chamber, a plurality of propeller fans are mounted in the duct, and the propeller fans are alternately arranged in opposite directions. At the same time, the wind speed in the duct is maintained at 20 to 30 m / sec, and the wind blown out from the outlet with a diameter of 30 to 40 mm provided on the outer wall of the duct is converted into hot air along the top surface by the heater provided near the outlet. Blowing out
It is good to circulate in a drying room. Further, in the drying method of the present invention, as in the invention previously filed (Japanese Patent Application No. 09-176839), as a material to be dried, all the side surfaces of the square bar were compressed and dewatered in advance. By using the square lumber, the drying time can be further reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method and apparatus for drying wood according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1A is a perspective view showing an example of a cylinder used in the wood drying method of the present invention, and FIG. 1B is a perspective view showing a state where the cylinder is placed on both ends of the wood. FIG. FIG.
FIG. 3 is a schematic plan view showing an example of the wood drying apparatus of the present invention, FIG. 3 is a side view thereof, and FIG. 4 is a front view thereof. FIG. 5 is a perspective view showing a state in which wood is piled on a cart carried into the drying apparatus of the present invention.

In the method for drying wood according to the present invention, hot air of 80 to 150 ° C. is blown out from an outlet of a duct provided in the upper part of the drying chamber, and is placed in the drying chamber by the hot air having a wind speed of 0.1 to 1 m / sec. The dried wood is dried, and the cylindrical body 1 used in this drying method is adapted to the cross-sectional shape of the wood to be dried.
When it is used for a square bar, as shown in FIG. 1A, the cross section is formed in a square tubular shape.

At the time of drying, as shown in FIG. 1 (b), both ends of the wood 2 are covered with the cylinder 1, and the small mouth of the wood is placed in the cylinder 50 to 100 so that the small edge 3 is not exposed from the cylinder 1. mm and placed in the drying room. An example of a drying apparatus that embodies the drying method of the present invention is shown in FIGS. As shown in FIG. 2, the drying apparatus includes a wood drying chamber 4 and a control chamber 5 for supplying and exhausting air to and from the drying chamber 4.

As shown in FIG. 3, a duct 6 is provided on the ceiling of the drying chamber 4.
A plurality of propeller fans 7 are provided on the left and right side walls 8, 9 of the duct 6.
, And are arranged alternately in the opposite direction. Further, air outlets (not shown) having a diameter of 35 mm are provided on the side walls 8 and 9 of the duct 6 at predetermined intervals, and a heater 10 as a heating source is provided near the air outlet on the outer wall of the duct 6. I have.

The inside of the duct 6 is maintained at a wind speed of 20 to 30 m / sec, and the inside of the drying chamber 4 has a desired flow of 0.1 to 1 m / sec or less, depending on the amount of air blown from the outlets provided in the duct side walls 8 and 9. It is adjusted so that the wind speed can be maintained. The wind blown out of the outlet is heated by a heater 10 provided in the vicinity of the outlet of the duct, and is applied to the wood in the drying chamber at a wind speed of 0.1.
Sprayed at ~ 1 m / sec.

A rail 11 is laid on the floor of the drying chamber 4, and a truck 12 on which wood is piled can move on the rail 11 as it is, and can be carried into and out of the drying chamber 4. . Ventilation in the drying chamber 4 is performed by an air supply pipe 13 and an exhaust pipe 14 leading to the drying chamber. The temperature and humidity in the drying chamber are controlled by a control panel 15, and the state at the time of setting is always maintained. As shown in FIG. 5, the drying of the timber is carried out by laminating the timber 2 having the cylindrical body 1 covered on both ends on a bogie 12, and
Is carried into the drying chamber 4 and the drying chamber 4 is sealed.
Dry according to the above procedure.

[0016]

[Example] Size 110 × 110 × 3600mm, average water content 130
% Dewatered square timber is previously dehydrated to an average moisture content of 100%.
A cylindrical body is placed over the edge of the timber so that a gap of 3 mm is formed between the timber and the timber.
The hot air was blown onto the timber and dried, and it was possible to dry to a moisture content of 18% without cracks or twists in 60 hours, even if the time required for raising and lowering the temperature was added.

[0017]

According to the method for drying wood of the present invention, the drying of the wood from the fore edge becomes gentle, the difference in the thermal conductivity between the surface layer and the inside of the wood becomes small, and the core portion of the wood in a short period of time. Can be sufficiently dried. In addition, by compressing the upper and lower surfaces and both side surfaces of the timber and drying the dewatered wood in advance by the method of the present invention, it is possible to further reduce the drying time. In other words, in the conventional method of drying wood using a dryer, the core-bearing square timber of 100% moisture content is dried to a moisture content of 18%.
The time (25-30 days) required only 40-70 hours (2
3 days), and can be dried sufficiently in a very short number of days without causing cracks or twisting.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view showing an example of a cylinder used in the wood drying method of the present invention, and FIG. 1 (b) is a perspective view showing a state where the cylinder is placed on both ends of the wood. It is.

FIG. 2 is a schematic plan view showing an example of a drying apparatus used in the drying method of the present invention.

FIG. 3 is a schematic side view showing an example of a drying apparatus used in the drying method of the present invention.

FIG. 4 is a schematic front view showing an example of a drying apparatus used in the drying method of the present invention.

FIG. 5 is a perspective view showing a state in which wood is piled on a cart carried into a drying chamber.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylindrical body 8, 9 Side wall of duct 2 Wood 10 Heater 3 Wood edge 11 Rail 4 Drying room 12 Dolly 5 Control room 13 Air supply pipe 6 Duct 14 Exhaust pipe 7 Propeller fan 15 Control panel

Claims (4)

[Claims] 1. A method for drying wood, comprising blowing hot air of 80 to 150 ° C. at a wind speed of 0.1 to 1 m / sec onto the wood from an outlet of a duct provided in an upper part of a drying chamber to dry the wood. 2. The method for drying wood according to claim 1, wherein the both ends of the wood are covered with a cylindrical body and dried. 3. The method for drying wood according to claim 2, wherein the cylinder is made of a material having a low water conductivity and a water absorbing property. 4. An apparatus for performing the method for drying wood according to claim 1, further comprising a duct having a plurality of fans and an outlet inside the drying chamber, wherein the fans are alternately arranged. And a control means for controlling the temperature and flow rate of hot air, the heat source being provided in the vicinity of the air outlet, and having a control means for adjusting the temperature and flow rate of the hot air.