JP2003170405A - Method and apparatus for drying by steam heating of lumber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make preparation of laminated wood having characteristics of being not warped, being not bent and going not wrong, easy by making penetration of heat good by drying with steam heating. <P>SOLUTION: In the case where lumber is dried at a specific set temperature and set humidity by making an inside of a drying warehouse a steam-heated space A, a sensor for detecting a temperature in the warehouse is provided. When the temperature in the warehouse rises by a tolerable upper limit temperature, for example, 1°C from the set temperature by detection with the sensor, introduction of steam is stopped and a part of heated air in the warehouse is exhausted to the open air. When the temperature in the warehouse drops by a tolerable lower limit temperature, for example, 1°C, the inside of the warehouse is humidified by introducing steam into the warehouse via a digesting pipe 6. The temperature and humidity in the warehouse are held by adjusting at the specific humidity by repeating those operations. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for drying wood by steam heating, and in particular, a small-diameter thinning material such as cedar and cypress is formed into a rough trapezoidal plate having a predetermined width, length and thickness. The present invention relates to a method and an apparatus for drying wood by steam heating, which is suitable for accommodating cut pieces in a stacked state in a drying cabinet and performing heat drying using steam.

[0002]

2. Description of the Related Art Due to the fact that most of the thinned wood is cut off and decayed in vast forests today, the development of applications for these thinned wood such as cedar and cypress is strongly demanded from the viewpoint of forest protection and environmental conservation. Therefore, as part of the effective use of these thinned wood, the development of laminated wood used for flooring materials, wall materials, furniture materials such as tables, and building materials is under way.

By the way, the laminated wood generally used in the past is an artificially dried, laminated narrow laminated plate in which the fiber directions of the selected narrow boards are joined in parallel. In order to dry wood, in addition to natural drying by exposing it to the air to release moisture, a steam drying method is used to progressively put the air in the drying chamber to heat the air in the drying chamber to release the moisture of the wood, and lower the air pressure in the drying chamber. There are used a vacuum drying method of drying water by extracting water from the wood, a high-frequency drying method of heating wood by using a high-frequency device, and the like.

[0004]

However, the equilibrium water content is about 20% at the most when the wood used for processing is dried by each of the above-mentioned drying methods during the production of laminated wood. ， When it is used for wall material, desk top plate or construction material, it may warp with the progress of use, and it may be bent and become out of order, adversely affecting the function of use,
Often, it impairs the appearance.

The present invention copes with the above-mentioned situation, and pays particular attention to the drying of lumber such as cedar and cypress used for the processing of laminated lumber, etc., and performs drying at a predetermined temperature and humidity using steam heating. By finding the above, it is possible to achieve efficient and effective drying, and to have excellent properties such as warp-free, bend-free and stable, and to make excellent laminated wood for various purposes. The purpose is.

[0006]

That is, a feature of the present invention which meets the above-mentioned object is drying of wood by steam heating,
In a method of storing and drying wood in a drying cabinet, as a steam heating atmosphere space in which steam coexists, the temperature and humidity of the space are set to required temperatures and humidity, respectively, and during drying, The temperature and humidity inside the refrigerator are monitored by sensors, and when the temperature inside the refrigerator rises above the predetermined set temperature to an allowable upper limit temperature, part of the air inside the refrigerator is exhausted to the outside air for ventilation. When the temperature falls and reaches the allowable lower limit temperature, steam is introduced to humidify, and the temperature and humidity inside the refrigerator can be constantly adjusted by repeating the above ventilation and humidification.

As a specific mode of the invention according to claim 2, a plurality of rough trapezoidal plate materials having a required width and length are juxtaposed, and the juxtaposed plate materials are stacked in a plurality of stages with a ventilation gap. On the trolley, a required number of the trolleys are accommodated in a drying cabinet, and steam is introduced into the cabinet to heat the stacked plate material at a predetermined set temperature and set humidity, and When heating the steam by installing a sensor that detects the temperature and humidity in the room, when the temperature in the room rises 1 ° C above the specified temperature due to the detection by the sensor, the introduction of steam is stopped and the air in the room is partially removed. On the other hand, it is discharged and ventilated, and on the other hand, when the temperature drops by 1 ° C., steam is introduced to humidify the inside of the refrigerator, and the temperature and humidity inside the refrigerator are adjusted and maintained at the predetermined set temperature and humidity by repeating this.

According to a third aspect of the present invention, there is provided an apparatus used for performing drying by steam heating as described above, which has an internal space having a required expansion, and a front door having a door for wood loading and unloading. The drying chamber has a heating chamber, which is open at both ends on the inner ceiling side thereof, has heating pipes inside, and is provided in parallel with a fan at a substantially central portion.
A steam pipe for injecting steam toward the inner space is provided under the open portions on both sides of the heating chamber, and an exhaust pipe for discharging the heated air in the storage chamber is provided under the heating chamber to penetrate the outer wall to enter the outside air. And a sensor for detecting the temperature and humidity inside the drying cabinet is installed at a required position of the drying cabinet.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Drying of wood such as cedar and cypress used in the laminated wood according to the specific embodiment of the present invention will be described below. Regarding the above-mentioned lumber used for laminated wood, lumber such as cypress, firstly, lumber such as cedar or cypress is cut into a predetermined length, usually about 50 to 80 cm, and this is cut into one piece to a rough trapezoidal shape. Processed and prepared dozens or dozens of similar things such as thickness, annual ring, color, material etc. with a crosspiece interposed, with a ventilation gap, stacking in multiple stages, usually 7 to 10 stages,
Ventilate well and dry, put this on a trolley and store a required number of it in a drying cabinet, and further artificially dry in the cabinet using steam to temporarily set the water content to about 8%, then Basically, the equilibrium water content is set to about 13% by curing.

Usually, the equilibrium water content of cedar or cypress used for wood processing is generally around 20%, so the cedar or cypress according to the present invention used for laminated wood is much smaller than that. It is the equilibrium water content, and heat drying using steam in the drying chamber of the present invention is an important drying process for obtaining excellent wood characteristics as an effective drying for that purpose.

FIGS. 1 to 3 show an example of a drying cabinet which is a main part of a drying apparatus for drying by steam heating according to the present invention. The drying cabinet 1 has an appropriate internal space A. Is provided with an entrance / exit door 2 for taking in and out the wood to be dried on one side, that is, the front surface, and the heating pipe 4 is provided by a hanging rod equipped with a turnbuckle 8 on the upper ceiling side inside thereof. The interior of the heating chamber 3 is suspended and held, and a plurality of fans 5 for uniformizing hot air are installed in the heating chamber 3 at substantially the center thereof.

Both sides of the heating chamber 3 are open to the inner space of the inside of the refrigerator, and the vaporizing pipes 6 for injecting steam to the inner space A are disposed at the lower portions on both sides of the opened heating chamber. The inside of the refrigerator is appropriately sprayed to form a steam heating space, while the lower portion of the heating chamber 3 penetrates the drying chamber 1 along the heating chamber and the outer wall 9 to penetrate the chamber. Exhaust pipes 7 for discharging a part of the heated air inside to the outside air are arranged in parallel, and when necessary, a part of the inside air can be discharged into the outside air by a blower to ventilate the inside. Has become. In addition, 10 is a sensor consisting of a psychrometer for detecting the temperature and humidity inside the drying chamber, which is attached to the required position of the drying chamber.
The vaporizing pipe 6 and the exhaust pipe 7 are provided so that each of the two pipes is provided so that the temperature and humidity inside the refrigerator can be maintained at the set predetermined temperature and humidity.
It is linked to the introduction of steam and the ventilation by discharging the heated air in the cabinet. In the figure, 11 is a gallery for air supply.

Thus, in the drying cabinet having the above-mentioned structure, rough trapezoidal wood having the required length and a width of about 8 to 15 cm and a thickness of about 3 to 5 cm is juxtaposed. When stacking a plurality of layers and loading them on a trolley, and accommodating a large number of the trolleys and performing drying according to the present invention, first, the temperature and humidity inside the refrigerator are set to predetermined temperatures and humidity, and steam at 130 ° C. is set. It is important to create a steaming space that holds the set temperature and set humidity and maintain the space. In this case, the set temperature and set humidity are usually 55 to 65 ° C.
In this range, the temperature is preferably set to 56 ° C. and the humidity is set to about 80%, but it may be set to 50 ° C. depending on the situation. Then, during the drying, the temperature is adjusted by the heating pipe 4 along with the vertical movement of the internal temperature by the detection of the sensor installed to maintain the above set temperature and set humidity, and the heating from the exhaust pipe 7 is performed. Part of the air is discharged, steam is introduced from the vaporizing pipe 6, or stopped. In this case, it is preferable that the upper and lower limits of the temperature be within ± 2 ° C with respect to the set temperature, and particularly preferably ± 1 ° C.

The situation will be described in more detail below.
Normally, 130 ° C steam is discharged into the refrigerator, and the temperature inside the refrigerator is maintained at the set value of 56 ° C. If the temperature inside the refrigerator rises 1 ° C during the drying process and it reaches 57 ° C, the sensor detection The valve of the steam supply pipe (not shown) is closed to stop the introduction of the steam, and the heated air in the refrigerator is partially exhausted by the blower through the exhaust pipe 7 to perform ventilation. When the temperature drops to 55 ° C and reaches 55 ° C, the valve is opened to introduce steam and the temperature is returned to the set temperature.

Then, the introduction of steam is stopped and ventilation is performed, and the introduction of steam is repeated during the drying by the detection of the sensor, whereby the drying is performed under the set temperature and humidity. At this time, the humidity is usually 85 at 57 ° C.
%, 76% at 55 ° C., so that the humidity is also adjusted by taking in and out steam.

As described above, the temperature and humidity in the storage are adjusted by introducing and exhausting steam, and the residual stress of the wood is appropriately removed by keeping the storage in the storage for about 6 hours.
In addition, the water content is once dried to about 8%. The moisture content is made into a preferable material for the subsequent laminated wood production by setting the equilibrium water content to about 13% by curing.

That is, the wood obtained as described above is processed into a trapezoidal cross section with both sides having an inclination of about 60 ° in the process of producing laminated wood, and usually 5-8 pieces are used. The wood surface, the back of the tree, the base opening, and the end opening are combined with each other and the inclination angles are combined, the mating surfaces are bonded with an adhesive, and pressed with a hot press or the like to be integrated to form a juxtaposed material.

Then, the juxtaposed material is further spliced in the longitudinal direction so as to have a required length to form an juxtaposed material having a required length.
If necessary, it is further laminated and pressed and integrated to be processed into a plate-shaped or block-shaped laminated material for various uses.

[0019]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a plurality of rough trapezoidal plate materials having a required width and length are dried side by side, and the juxtaposed plate materials are provided with a ventilation gap. When stacking a plurality of tiers and placing them on a trolley, storing a required number of the trolleys in a drying cabinet, and introducing steam into the cabinet to dry them, the inside of the cabinet is heated to a predetermined set temperature and set humidity atmosphere. In addition to forming a space, a sensor that detects the temperature and humidity inside the refrigerator is installed, and when the temperature of the inside of the refrigerator rises above the predetermined set temperature due to the detection of the sensor, the introduction of steam is stopped. Ventilation of the air inside the refrigerator, and on the other hand, when it falls to the allowable lower limit temperature, steam is introduced to humidify the inside of the refrigerator to adjust and maintain the temperature and humidity inside the refrigerator at the predetermined set temperature. Since it is heated by steam heating, it is better than hot air heating. Penetration into the interior wood is uniform, and
Good and stable drying is possible, and because the steam is repeatedly taken in and out within the allowable upper and lower limits, preferably ± 1 ° C, it is possible to efficiently modify the wood by the breathing effect and remove residual stress. It is extremely effective, and when used as a flooring material, wall material, flooring material, etc., as a laminated material, it retains the characteristics of not warping, bending, and getting entrenched, and has a remarkable effect on the formation of accurate materials. Have

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an internal configuration of a drying cabinet used in the present invention.

FIG. 2 is a schematic view of the internal configuration of FIG. 1 viewed from the side.

3 is a schematic plan view of the internal configuration of FIG. 2. FIG.

[Explanation of symbols]

1 drying cabinet 2 doorway 3 Air heating chamber 4 Heating piping 5 fans 6 evaporation tube 7 exhaust pipe 8 turnbuckles 9 outer wall 10 sensors

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigenori Izumi             48, 2-650, Meito-cho, Tokushima City F term (reference) 2B230 AA15 BA01 EA21 EB06 EB12                       EC00 EC21                 3L113 AA01 AB02 AC05 AC43 AC45                       AC46 AC48 AC49 AC53 AC67                       BA05 CA08 CA09 CB24 DA11                       DA24

Claims (3)

[Claims] 1. A method for storing and drying wood in a drying cabinet, wherein the interior of the cabinet is a steam heating atmosphere space in which steam coexists, and the temperature and humidity of the space are set to a predetermined temperature and humidity, respectively. At the same time, during drying, the temperature of the inside
Humidity is monitored, and when the temperature inside the cabinet rises above the preset upper limit to the allowable upper limit temperature, part of the air inside the cabinet is exhausted to the outside air for ventilation, while the internal temperature decreases and the allowable lower limit is reached. A method for drying wood by steam heating, characterized in that when temperature is reached, steam is introduced to humidify and the temperature and humidity inside the refrigerator are adjusted by repeating the above-mentioned ventilation and humidification. 2. A plurality of rough trapezoidal plate members having a required width and length are juxtaposed, and the juxtaposed plate members are stacked on a truck by a plurality of stages with a ventilation gap, and the truck is placed in a drying cabinet. The required quantity of steam is introduced, and steam is introduced into the storage to heat the stacked plate material at a predetermined set temperature and humidity, and a sensor for detecting the temperature and humidity inside the storage is installed. During heating, when the temperature in the refrigerator rises 1 ° C above a predetermined set temperature as detected by the sensor, the introduction of steam is stopped and the air in the refrigerator is partially exhausted for ventilation, while the temperature has dropped 1 ° C. At this time, a method for drying wood by steam heating is characterized in that steam is introduced to humidify the inside of the store and the temperature and humidity inside the store are adjusted to the predetermined set temperature and humidity by repeating the process. 3. A device for drying wood by steam heating, comprising a drying cabinet having an internal space having a required expansion and a front door for loading and unloading wood, the drying cabinet being on the inner ceiling side thereof. The heating chambers with both ends open to the inside are equipped with heating pipes and are installed side by side with a fan at approximately the center, and steam is injected toward the internal space at the lower part of the opening on both sides of the heating chamber. There is a vaporizing pipe that is installed in the lower part of the heating chamber, and an exhaust pipe that discharges the heated air inside the chamber penetrates the outer wall and extends into the outside air. A dryer for heating wood by steam, which is equipped with a sensor that detects the internal temperature and humidity.