JP3406282B2 - Wood drying equipment and wood drying method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to a drying apparatus and a method for drying the raw material, in particular, hit the drying of wood dimensional accuracy and yield are required, such as building materials, timber
The cracking and difficulty cause deformation of warp, moreover relates wood drying method using it with wood drying apparatus capable of drying hard preservatives or termiticide is easily dried in impregnated wood.

[0002]

Wood used in construction and the like is used after drying wood which is a raw material. Conventionally, as a method of drying wood, which is a raw material, generally, a method of forcibly steaming raw wood introduced into a drying chamber with steam, then raising the temperature in the drying chamber to dry and remove water is taken. It was being done.

Further, as another method for drying wood and the like,
The method of heating wood with steam was also widely used. Further, Japanese Patent No. 2828625 by the applicant of the present application discloses, as a method for drying raw wood using a far-infrared heater, far-infrared rays that radiate far-infrared rays toward raw wood that is an object to be dried. A wood drying device with a heater is described.

[0004]

However, in the former method of drying wood, since the steam is once steamed and then dried by steam heating, it takes a long time to dry the wood, and therefore the efficiency is extremely high. It was bad. In particular, the water content of wood begins to dry from its surface, and the water content remains inside, and even after a long time, the water content inside remains.

Further, since the drying temperature inside and on the surface of the wood greatly differs, the size and shape of the wood once cut into a predetermined size change. Further, due to the destruction of the cells and components of the wood, for example, only the central portion of the cross section of the wood such as timber tends to contract and become thin, cracked, twisted, or bent or warped in the straight portion. Therefore, there is a problem that the yield of wood deteriorates.

In the latter method of drying wood using a wood drying apparatus, since a far-infrared heater is used, the central part of the wood is evenly heated, activated and evaporated, so that the moisture in the central part is removed. Easily, and when the wood evaporates, the water evaporates from its interior and surface almost evenly and dries. Therefore, it is possible to uniformly dry the wood in a short time, and the wood is relatively free from cracking and deformation, and the drying yield can be improved.

However, even in the latter wood drying apparatus, when the wood is rapidly dried, it may be pulled, shrunk, or expanded during the wood drying process, and the wood may be cracked or deformed. Furthermore, in recent years, wood pre-cutting plants have come to perform antiseptic and anti-termite treatment on wood. This antiseptic and ant-proof treatment replaces conventional arsenic compounds and chromium compounds,
This is carried out by using a safer chemical consisting of a solution of copper and an alkylammonium compound, impregnating wood with this chemical, and then drying. In the impregnation of the chemicals, there is a cell membrane peculiar to wood, and it is difficult to permeate the inside, so that a method of injecting under high pressure (15 Kg / cm ² for 2.5 hours) is adopted.

However, since the chemical agent consisting of a solution of copper and an alkylammonium compound is highly hydrophilic, wood impregnated with the chemical agent has high water retention and is difficult to dry. for that reason,
In ordinary natural drying, it takes a long time to dry, and incomplete drying tends to occur. An object of the present invention, the light of the problems in the prior art, to reduce cracking or deformation caused to the wood during the drying, wood dimensional accuracy is required, such as building materials
Suitable for drying wood , and wood impregnated with chemicals that are difficult to dry
To provide a wood drying method using it and wood drying apparatus that can easily dry even wood.

[0009]

In order to achieve the above object, in the present invention, a spray water spray nozzle 3 is provided in a drying chamber 11 together with a far infrared heater 2 for heating and drying wood , and this spray water spray nozzle 3 is used. The humidifying conditions in the drying chamber 11 can be adjusted. Then, the wood 9 is efficiently heated by far infrared rays and dried.

That is, the wood drying apparatus according to the present invention is
A drying chamber 11 for storing wood 9 to be dried, and this drying chamber 1
Far-infrared heater 2 for heating wood 9 stored in 1
And a circulation fan 4 for circulating the air in the drying chamber, an air supply fan 13 for introducing outside air, and an exhaust fan 8 for exhausting the air in the drying chamber 11 to the outside of the drying chamber 11, and further the drying chamber 11 A water spray nozzle 3 for spraying water to the wood 9 introduced into the drying chamber 11 is provided therein.

[0011] Wood drying <br/>燥方method using such a timber drying apparatus, the timber 9 is accommodated in the drying chamber 11, far infrared drying chamber timber 9 housed in 11 in the far infrared heater 2 by emitting, to evaporate moisture of the wood 9, but by the exhaust fan 3 water evaporated from the wood 9 from the drying chamber 11 is to exhaust (water removal), by spraying water spray nozzle 3, wood drying schedule According to the set value, the tree in the process of drying
Appropriately watering timber 9, characterized by moisturizing wood 9.

In the method of the wood drying apparatus of the present invention, since the heat passes to the center of the wood due to the effect of the far infrared heater 2, moisture in the center is easily removed, and the inside and the surface of the wood 9 being dried are easily separated. The water content can be made uniform. Therefore, achieving a reduction in cracking or deformation of the timber 9, it is possible to dry the wood 9.

Furthermore, in the case of wood drying timber 9 is impregnated with the preservative and anti-termite agents, far infrared rays, for further wavelength than visible light is long wave, penetrates into the wood,
It excites water molecules bound to components such as copper and alkylammonium salts of preservatives and termites to break the bonds.
Therefore, water molecules bound to the preservatives and termites can be quickly released to the outside of the wood and dried,
The wood can be dried almost completely in no time.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described specifically and in detail with reference to the accompanying drawings. FIG. 1 and FIG. 2 show the internal structure of a wood drying apparatus as an embodiment of the present invention.

As shown in FIG. 2, the wood drying apparatus is
The inside has a drying chamber 11 which is partitioned from the outside, and the drying chamber 11 has an internal space formed by the housing 1. Specifically, the housing 1 is built in a box shape by, for example, a prefabricated method. In addition,
The shape of the housing 1 is not limited to the box shape, but may be, for example, a house shape or a shed shape having a roof on the upper part, and it goes without saying that the building material is not limited to the prefabricated structure. Yes. Also, this drying room 11
May be placed inside the building, or may be placed outdoors with the housing 1 as described above.

As shown in FIG. 1, this housing 1
A shutter door 12 is attached to the front of the.
Further, two sets of rails 5 are laid on the concrete base 10 on which the housing 1 is built from the outside of the shutter door 12 to the drying chamber 11 in the housing 1. A carriage 6 is movably mounted on the rail 5 via wheels 7. The wood 9 to be dried is stacked on the dolly 6 outside the shutter door 12, and then the dolly 6 is run along the rails 5 to bring the wood 9 into the drying chamber 11 in the housing 1. The dried wood 9 is carried out of the drying chamber 11 by the reverse procedure.

In the drying chamber 11 in the housing 1,
A plurality of far-infrared heaters 2 are arranged, for example, the far-infrared heaters 2 are attached to the inner walls on both sides of the housing 1. An air supply fan 13 for supplying air to the drying chamber 11 is provided above the front wall of the housing 1, and the front wall of the housing 1 faces the front wall of the housing 1. A plurality of exhaust fans 8 for exhausting the air in the drying chamber 11 are provided in the upper part. Further, on the ceiling of the housing 1, a plurality of circulation fans 4 are arranged in a line in the front-back direction of the paper in FIG.

In the above embodiment, both the air supply fan 13 and the exhaust fan 8 are provided, but only the exhaust fan 8 is provided, and the air supply is replaced by ventilation means having a damper in the ventilation window. Is also possible. Between the ceiling and both side walls of the housing 1, a plurality of spray watering nozzles 3 are attached in a line in the front-back direction of the paper in FIG. 2, and the spray watering nozzles are stacked on the carriage 6 and should be dried. wood
It is installed toward the material 9.

Next, the wood drying method executed by the wood drying apparatus will be described in detail. As described above, the shutter door 12 on the front surface of the housing 1 is opened, and the carriage 6
Is pulled out to the outside of the housing 1, and here the timber which is the timber 9 to be dried is piled up on the carriage 6. After that, the carriage 6 is moved along the rail 5, and then the shutter 12 is closed to make the drying chamber 11 in the housing 1 a space which is shielded from the outside, and the wood 9 is stored therein.

Next, the circulation fan 4 is operated to drive the drying chamber 11
The wood 9 stored in the drying chamber 11 is supplied with electric power to the far-infrared heater 2 while circulating the air inside.
Emits far infrared rays. At this time, the air supply fan 13 and the exhaust fan 8 are stopped or operated by adjusting the amount of exhaust so that the drying chamber in the housing 1 is kept in a substantially non-exhausted or very conservative ventilation state. As a result, the wood 9 in the drying chamber 11 is heated by the far-infrared rays emitted from the far-infrared heater 2, moisture contained in the wood 9 is heated and evaporated, and the vapor is released to the drying chamber 11. It Due to the water evaporated from the wood 9, the drying chamber 1
When 1 is satisfied, the humidity is saturated, that is, the humidity is 100.
%. At this time, in the temperature measurement by the dry and wet bulb in the drying chamber 11, the difference between the measured temperature values of the dry and wet bulb is 0 regardless of the temperature.

[0021] By the far-infrared in the manner described above to emit the timber 9, when heated to evaporate water from the timber 9, the far infrared rays is strong penetration force, in proportion to the elapsed time until the interior of the timber 9 penetration To do. Therefore, of the water contained in the wood 9, not only surface-adsorbed water and free water that evaporate relatively quickly, but also bound water inside the tissue of the wood 9 that is hard to evaporate can be evaporated.

[0022] In addition, the drying chamber 11 is a closed state, tree
Since the humidity is increased by the moisture released from the inside of the material 9, only the surface-adsorbed water and the free water, which are likely to evaporate relatively quickly, are prevented from evaporating rapidly, and the bonding of the timber 9 inside the tissue is prevented. Water also evaporates from time to time. Therefore, the evaporation rate of water from the inside of the wood 9 does not have an extreme difference between the surface-adsorbed water, free water and bound water, and a so-called uniform and uniform evaporation rate of water can be obtained. In other words, the evaporation rate of the uniform moisture from the whole wood 9, such as cracking or bending occurs in timber 9, further, tar coming out from the inside to the surface of wood 9, the portion of the section timber 9 out surface It is possible to prevent the occurrence of distortion of the wood 9 due to drying, including the phenomenon of forming a concave portion in the inner wall, that is, including "ditch, knot". Further, since the inside and outside are uniformly heated and evaporated by the radiation of far infrared rays, it is possible to dry in a relatively short time without applying a too high temperature. Therefore, the material of the wood 9 does not deteriorate.

After that, the air supply fan 13 and the exhaust fan 8 are driven to ventilate the air in the drying chamber 11. At the same time, the power supply to the far infrared heater 2 is controlled to adjust the amount of far infrared radiation to the wood . That is, the drying of the wood 9 is promoted by ventilating the humid air in the drying chamber 11 containing the moisture discharged from the wood 9 by the radiation of far infrared rays with the outside air.

At this time, when the humidity in the drying chamber 11 suddenly drops, that is, when the difference between the temperature measurement values by the dry and wet bulbs in the drying chamber 11 becomes large, the air supply fan 13 and the exhaust fan 8 The ventilation in the drying chamber 11 is stopped and the water is sprayed from the spray watering nozzle 3 to the drying chamber 11. As a result, an appropriate in-machine humidity condition is adjusted according to the degree of drying of the wood 9.

Furthermore, the far-infrared heater 2 radiates far infrared timber 9, to dry the wood 9 in the same manner as described above. As a result, cracking and deformation of the wood 9 are further prevented, and the quality of the wood 9 is completely maintained. For example, FIG. 3 is a time chart showing an example of temperature and humidity settings in a wood drying schedule using the wood drying apparatus and an example of actually measured values of temperature and humidity in the drying chamber 11. The solid line is the setting example, and the broken line shows the actual measurement value in the drying chamber 11 at that time. The upper chart is temperature, the lower chart is humidity, and time is shown correspondingly to the top and bottom.

As shown in the upper part of FIG. 3, the total drying time 408
Of the time, the set temperature in the drying chamber 11 for the first 100 hours is raised to 60 ° C. The measured temperature in the drying chamber 11 is as low as 40 ° C. initially, but the temperature gradually approaches the set temperature. After the measured temperature of the drying chamber 11 reaches the steady state of 50 ° C., the set temperature is lowered to 50 ° C. in about 100 hours, and the set temperature is kept 308.
Keep on time.

On the other hand, the set value of the humidity in the lower row is shown by three numerical values: humidity / dry / wet bulb temperature difference / equilibrium water content of wood . From the initial setting of high humidity in the drying chamber 11 and high equilibrium moisture content of wood , the relative humidity in the drying chamber 11 gradually decreased,
Change to a setting with a low equilibrium water content of wood .

In this state, the actually measured humidity of the drying chamber 11 gradually approaches the set value. At this time, when there is a sudden decrease in the measured relative humidity, water is sprayed from the water spray nozzle 3 to the drying chamber 11 to adjust the humidity condition. As a result, it is possible to reliably prevent the wood 9 from being cracked or deformed. After such a drying schedule, finally, the relative humidity of the drying chamber 11 becomes about 10%, and the dry water content of the wood 9 becomes about 5 to 15%.

After the drying of the wood 9 is completed, the power supply to the far infrared heater 2 in the drying chamber 11 is stopped and the air supply fan 13
Then, the exhaust fan 8 is operated to return the drying chamber 11 to an environment almost the same as the outside air. After that, the shutter door 12 is opened and the carriage 6
The wood 9 placed on the table is taken out of the drying chamber 11. Then, outside the drying chamber 11, the wood 9 is loaded on a truck or the like and carried out.

[0030]

[Examples] Next, (Example 1), using the drying apparatus, the dimensions, 107 (W) × 107
The results of drying cedar squares of (D) × 3030 (L) (mm) are shown in Tables 1 to 3 below.

Here, based on the moisture content of the lumber that is the original wood 9, the dry and wet temperature, that is, the dry-bulb temperature in the drying chamber 11 is set for each moisture content range to be dried as shown in the leftmost column of each table. Wet-bulb temperature difference, drying chamber 11 calculated from them
The relative humidity and the equilibrium water content are shown. The range of water content to be dried was adjusted by the temperature of the far infrared heater 2 and the spraying of water into the drying chamber 11 by the spray watering nozzle 3. Wood made by any of the drying schedules shown in Tables 1-3
When the material 9 was dried, no cracks, bends, tars, knots, etc. of the dried wood 9 were found.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

(Example 2) Using the above drying apparatus, standard size, 105 (W) x 10
Table 4 shows the results of drying the square wood obtained by impregnating 5 (D) × 800 (L) (mm) rice bran with a solution chemical of copper and an alkylammonium compound under pressure injection. Here, the specific gravity of the wood when fully dried is 0.42 g / cm ³ , and the actual wood
The value obtained by multiplying the volume of the material is taken as the total dry weight, and the estimated water content is calculated by ( wood weight−total dry weight) / total dry weight × 100.

As shown in Table 4, except for sample 6,
In each case, the drying time was 48 hours and the initial value was 17.8% to 38.
The water content of 3% could be dried to a water content of 0 to 13.4%. Since Sample 6 had a high initial water content of 51.6%, the water content after 48 hours was 3%.
Although it could not be sufficiently dried at 5.7% in 48 hours, it could be sufficiently dried by setting the drying time to 72 hours.

[0037]

[Table 4]

[0038]

As described above, in the wood drying apparatus and method of the present invention, in the drying of raw wood , at the same time, a sufficient degree of dryness can be obtained, and at the same time, distortion such as cracks and bends that may occur in the wood during the drying. Occurrence can be reduced. This makes it possible to provide a suitable timber drying process to dry the dimensional accuracy is required timber, such as construction materials.
Furthermore, even wood which is hard to dry and which has been subjected to antiseptic and ant-prevention treatment can be quickly dried in 48 hours to 72 hours.

[Brief description of drawings]

FIG. 1 is a front view of a wood drying apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the same wood drying apparatus.

FIG. 3 is a chart diagram of set values such as temperature and humidity and measured values showing a schedule of a wood drying process performed by the wood drying apparatus.

[Explanation of symbols]

2 Far infrared heater 3 Sprinkling nozzle 9 Wood 11 Drying room

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B27K 5/00 B27K 3/02 B27K 3/52 F26B 9/06

Claims (4)

(57) [Claims] 1. DryingwoodDrying room for storing (9)
(11) and stored in this drying chamber (11)wood
Far infrared heater (2) for conductively heating (9) and drying
A circulation fan (8) for circulating the air in the chamber (11) and the outside
An air supply fan (13) for supplying air, and a drying room (1
Wood drying having an exhaust fan (3) for exhausting air to the outside of 1)
In the drying device, it is installed in the drying room (11)
Was enteredwoodA spray nozzle (3) that sprays and sprays water on (9)
Characterized by providing a temperature and humidity detection sensor (14)
RuwoodDrying device. 2. Wood (9) to be dried is impregnated with a preservative and / or a termite control agent.
The wood drying apparatus according to item 1 . 3. A timber (9) housed in the drying chamber (11), by emitting far-infrared rays in the far infrared heater (2) into the drying chamber (11) within the housing wood (9), the radiation conductive heat rises the temperature of the timber (9), evaporates the moisture of the wood (9), timber drying process for exhaust by the exhaust fan (3) the moisture evaporated from the timber (9) from the drying chamber (11) In the drying chamber (1
By controlling the temperature, the humidity value of 1), the tree
A method for drying wood , characterized in that the drying speed of the material (9) is adjusted. 4. The wood (9) to be dried is impregnated with a preservative and / or a termite control agent.
The method for drying wood according to .