JP3517202B2 - Wood drying method and drying equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an apparatus for heating raw wood or rod-shaped wood lumbered in a column shape by microwaves to dry it.

[0002]

2. Description of the Related Art When wood is used in an undried state,
There are various adverse effects such as large deformation over time or contraction to form a gap. This adverse effect can be prevented by drying the wood. The most common method of drying wood is to let it dry naturally, but this method is extremely time consuming. As a method of drying wood in a short time, a method of heating wood with steam, far infrared rays, or high frequency has been put into practical use. In the method of heating with steam, the wood is heated to 100 ° C. or higher in order to boil the water contained in the wood and remove it in a short time. Therefore, wood is placed in a pressure tank and steam of 100 ° C. or higher is supplied. This method has a drawback that a pressure vessel is required to heat wood to 100 ° C. or higher, resulting in extremely high equipment cost. Also, in the method of heating wood with steam or far infrared rays, heat is conducted by conducting heat from the surface of the wood, so it takes a considerable time to heat the wood to the inside, and the wood is efficiently dried in a short time. Is difficult. In particular, pillars, logs, and the like take a long time to heat the central part and cannot be dried in a short time. Further, this method has a drawback that the surface is shrunk and easily broken because the wood is dried from the surface.

As a device for heating wood from inside, a device for heating and drying wood by sandwiching it between high frequency electrodes has been put into practical use. This device heats the wood with the high frequency loss of the wood placed between the electrodes. This device can dry thin wood such as plate material relatively efficiently. However, there is a drawback in that it is not possible to efficiently heat wood with a large surface area, such as pillars, or round wood, such as raw wood. that is,
This is because pillars and the like cannot be sandwiched by wide electrodes, and when logs are sandwiched by planar electrodes, it becomes impossible for wood to efficiently absorb high frequencies. Furthermore, this device has different ideal electrode shapes and sizes depending on the shape and size of the drying wood,
There is also the drawback that it is difficult to dry different woods with the same equipment. Further, there is also a bad effect that a high frequency wave becomes a radio wave from between the electrodes and is radiated to the surroundings.

An apparatus for irradiating wood with microwaves to dry it has an excellent feature that an apparatus sandwiched by electrodes does not have. In particular, this drying device radiates microwaves to the wood and heats it due to the dielectric loss of the wood, so the interior of the wood, which takes a long time to dry, can be heated more efficiently. Therefore, there is a feature that thick wood can be heated to the inside in a short time.

[0005]

Since the apparatus for heating wood by microwaves heats the wood internally, the microwave output can be increased and the drying time can be shortened. The usual way,
This is because, for example, the inside of thick wood can be heated quickly as compared to the method of heating from the outside with steam or infrared rays. However, the method of irradiating wood with microwaves to dry has a problem that the dried wood is easily bent. This is because the microwave-heated wood is heated to a high temperature inside to be softened and easily deformed. Especially,
Since raw wood and timber have a small surface area with respect to volume, the internal temperature of the timber and timber tends to rise and become soft when irradiated with microwaves. For this reason, if the wood is held horizontally and irradiated with microwaves, there is an adverse effect that the wood sags and bends due to its own weight. In order to eliminate this drawback, the present inventor has developed a device for drying the wood 1 while rotating it, as shown in FIGS. 1 and 2. This dryer is wood 1
Since it is placed on a plurality of sets of rollers 35 and dried while rotating, the bending of the wood 1 can be reduced. However, in the drying device having this structure, it is difficult to put a large number of pieces of wood together in the shield case 2 for drying, and it is not possible to efficiently dry a large number of pieces of wood. Further, the structure is complicated and the manufacturing cost becomes high. Furthermore, although this drying device can rotate and dry cylindrical wood such as logs, it cannot rotate square timber such as pillars or raw wood whose outer shape is not constant. For this reason, there is also a drawback that logs that can be dried are specified as logs.

A first object of the present invention is to eliminate such drawbacks, that is, to provide a drying method and apparatus capable of drying not only logs but also thick and heavy logs or timber without bending. . Another important object of the present invention is to
It is an object of the present invention to provide a drying method and apparatus capable of efficiently drying a large amount of wood together.

Further, in a device for heating wood with microwaves, microwaves are oscillated by a magnetron and radiated into a shield case by a waveguide. Since the microwave radiated from the waveguide has directivity, it is difficult to uniformly irradiate the entire wood put in the shield case with the microwave.
Since the drying apparatus shown in FIGS. 1 and 2 irradiates microwaves while the wood 1 is placed on the roller 35 and rotated, one log can be uniformly irradiated with microwaves. However, in the drying device having this structure, it is not possible to put a large number of pieces of wood, such as lumber and logs, that are not logs together in a shield case and irradiate each wood with microwaves uniformly. For this reason,
There is a drawback that a large number of woods cannot be efficiently dried by being uniformly irradiated with microwaves.

The present invention was developed for the purpose of eliminating such drawbacks, and the second object of the present invention is to efficiently irradiate a large number of woods with microwaves for efficient drying. It is to provide a drying method and apparatus.

Further, the method of microwave-drying wood has a drawback that if the output of microwaves is increased in order to shorten the drying time, the wood is easily broken. that is,
This is because the microwave heats the wood from the inside, so that the water boils inside the wood and the internal pressure becomes abnormally high.
Wood cracking during the drying process significantly reduces the commercial value of wood. This drawback can be solved by reducing the output of the microwave generator. However, if the output is reduced, the drying time becomes longer and it becomes impossible to dry in a short time. For this reason, it is difficult for the method of drying wood by microwaves to quickly dry the wood while preventing the wood from cracking.

The present inventor does not continuously irradiate the wood with the microwave, but irradiates the wood with the microwave for, for example, 1 hour, but interrupts the microwave irradiation for the subsequent 1 hour, and thereafter, the microwave is applied. We succeeded in preventing wood cracking by developing a method of drying by repeating irradiation and interruption of wood. This drying method is a step of interrupting the irradiation of microwaves, whereby water inside the wood is transferred to the surface and the water can be uniformly dispersed in the whole wood. When the internal temperature of wood becomes high, water boils inside and the internal pressure rises abnormally. If microwave heating is further performed in this state, the wood will crack, but when microwave irradiation is stopped, the pressure rises. Moisture inside migrates to the surface quickly. When the internal moisture moves to the surface and the internal pressure decreases, the boiling point of water decreases, and the water easily boil, and the internal temperature of the wood decreases due to the heat of vaporization. Further, when the water moves to the surface, the internal pressure of the wood decreases, but at this time, the water that moves to the surface passes through the wood conduit and is smoothly guided to the outside. Therefore, the method of temporarily interrupting the irradiation of microwaves on wood has a feature that cracks on the wood can be reduced.

Further, in the case of wood, the microwave output is controlled by turning the microwave output on and off in the heating state of the wood instead of repeating microwave irradiation and interruption for a fixed time, or the microwave output is continuously changed at the wood temperature. Even with the method of controlling to 1, the wood can be quickly dried with less cracks. In this drying method, for example, the temperature of the wood is detected, and when the temperature of the wood reaches a set temperature, the output of the microwave is stopped or the output is reduced to transfer the moisture inside the wood to the surface. Also in this method, it is possible to effectively prevent the cracking of wood by migrating water to the surface promptly.

A method of drying while preventing the cracking of wood by stopping or controlling the output of microwaves is as follows:
It is important how quickly the internal water can be transferred to the surface when the internal pressure rises. If moisture cannot be rapidly transferred to the surface, the time to stop irradiation of microwaves or reduce the output becomes long, the overall drying time becomes long, or the rise in internal pressure cannot be quickly reduced, so This is because cracking will occur.

As a result of further experimentation, the present inventor has found that the water inside wood is quickly flown down along a conduit by a simple method of irradiating microwaves while vertically suspending and transferring wood. Successful. Therefore, the third important object of the present invention is to minimize the cracking of wood,
It is an object of the present invention to provide a drying method and a drying apparatus for wood that can uniformly and quickly dry the whole wood.

[0014]

According to the drying method of the present invention, wood 1 is microwave-dried. The wood 1 which has been heated by microwaves and has a high internal temperature quickly transfers the water content inside to the surface along the conduit of the wood 1. In order to drain water more smoothly, the wood 1 is hung and transferred with the conduit as the vertical direction. Further, the wood 1 that is hung in the vertical posture by the hanging conveyor 6 and transferred is rotated about the vertical axis.

The rotating wooden piece 1 is irradiated with microwaves from the side surface. The rotating wood 1 is a microwave generator 3
The position facing the antenna of changes. The microwave radiated from the antenna toward the wood 1 is transmitted through the wood 1 as shown in FIG.
The wood 1 is absorbed by and is heated. Microwaves absorbed by the wood 1 and transmitted while heating are gradually attenuated
Through. Therefore, the portion of the wood 1 that faces the antenna 36 is heated by the strong microwaves, but the opposite side is weakly heated by the microwaves that have passed through the wood 1 and are attenuated. When the wood 1 becomes thicker, the opposite side of the antenna 36 is heated by the attenuated weak microwave. Therefore, the rotating wood 1 heats a part of the wood 1 (A portion facing the antenna in the figure) with a strong microwave at one time, but when the wood is rotated 180 degrees, The opposite side is irradiated with a weak microwave. That is, the wood 1 partially has an irradiation part to which strong microwaves are applied and a non-irradiation part to which weak microwaves are applied. Since the wood 1 is transported while rotating, the irradiation portion and the non-irradiation portion change in synchronization with the rotation speed. Therefore, a part of the wood 1 heated to a high temperature in the irradiated portion transfers the water heated to a high temperature and a high pressure to the surface when it becomes a non-irradiated portion. Therefore, in the method for drying wood according to the present invention, the whole wood 1 is uniformly microwave-heated, but the whole wood is not always uniformly irradiated with microwaves, but the irradiation part and the non-irradiation part are partially irradiated. While being installed, the whole is uniformly heated and dried.

This unique dry condition is important for drying the wood without cracking. It is because when the wood is continuously heated by microwaves, the heated water inside the wood evaporates, the evaporated water vaporizes and the pressure inside the wood rises, and the increased internal pressure expands the wood and cracks it. This will cause The drying method of the present invention in which microwaves are applied while repeating irradiation and non-irradiation portions, when the non-irradiation portions are formed, moisture inside is transferred to the surface to effectively prevent increase in internal pressure. Therefore, the wood can be dried quickly without cracking. In the drying method of the present invention, the rotating wood 1 is 1
The rotation time can be 1 minute to 1 hour.

Further, in the drying method of the present invention, the wood 1 may be dried by repeating the microwave irradiation step of irradiating the wood 1 with the microwave and the microwave interruption step of interrupting the irradiation of the wood 1 with the microwave. it can. According to this drying method, when the wood 1 is irradiated with microwaves, the irradiation part and the non-irradiation part are provided and heated, and further, the time for interrupting the microwave irradiation is provided, so that the wood heated by the microwave is used. It is possible to more reliably reduce the increase in internal pressure of No. 1 and reduce cracking.

Further, in the drying method of the present invention, the wood sensor 4 can control the microwave output. In this drying method, the wood sensor 4 can detect any of the temperature, water content, and weight of the wood 1 to control the microwave output. Further, in this drying method, the wood sensor 4 can be used to detect smoke generated from the wood 1 to control the microwave output.

The drying apparatus of the present invention includes a shield case 2 for containing the wood 1 to be dried, a suspension conveyor 6 for suspending and transferring a plurality of woods 1 in the shield case 2, and a side surface of the shield case 2. A plurality of microwave generators 3 are provided for irradiating the wood 1 inside with microwaves. The plurality of microwave generators 3 are arranged at a predetermined interval so that the hanging conveyor 6 is separated in the direction in which the hanging conveyor 6 is transferred, and irradiate the transferred wood 1 with microwaves. The hanging conveyor 6 includes a rotating mechanism 23 that rotates the wooden piece 1 that is being hung and transferred, around the vertical axis. The hanging conveyor 6 transfers the wood 1 while rotating it by the rotating mechanism 23, and the microwave generator 3 irradiates the wood 1 with microwaves from the side surface to dry the wood 1.

In the drying device, the microwave generator 3 can be controlled by the wood sensor 4. This wood sensor 4
By detecting the heating state of the wood 1 and controlling the microwave output, the wood 1 can be brought into a microwave irradiation state and a state in which the microwave irradiation is interrupted or limited. Further, in the drying device, the shield plate 8 is arranged inside the shield case 2 to irradiate the wood 1 with microwaves,
It can be in a state where microwaves are not irradiated. This drying device includes a shield plate 8 and a shield case 2
The inside of is divided into a shield region 10 for shielding microwave irradiation and a microwave irradiation region 9 for microwave irradiation. This drying device transfers the wood 1 to the shield area 10 and the microwave irradiation area 9 by the hanging conveyor 6, heats the wood 1 in the microwave irradiation area 9, and removes the water content of the wood 1 in the shield area 10. Allow to flow down the conduit.

Furthermore, the drying device controls the microwave generator 3 to irradiate the wood 1 transferred by the hanging conveyor 6 with microwaves for a certain period of time and stop the irradiation of microwaves for a certain period of time. And a control circuit 5 for limiting. This drying device transfers the wood 1 on the hanging conveyor 6 and heats the wood 1 in the state of being irradiated with microwaves,
When the microwave irradiation is stopped or limited, the water content of the wood 1 is caused to flow down along the conduit.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. However, the following examples exemplify a drying method and a drying apparatus for wood for embodying the technical idea of the present invention, and the present invention does not specify the drying method and the following apparatus.

Further, in this specification, in order to make the claims easy to understand, the numbers corresponding to the members shown in the embodiments are referred to as "claims column" and "to solve the problems". It is added to the members shown in "Means column". However, the members shown in the claims are not limited to the members of the embodiment.

The wood drying apparatus shown in the plan views of FIGS. 3 and 4 and the front view of FIG. 5 has a shield case 2 into which the wood 1 is carried, and the wood 1 is hung vertically inside the shield case 2. A hanging conveyor 6 for transferring the wood 1, a plurality of microwave generators 3 for irradiating the wood 1 in the shield case 2 with microwaves, and a wood sensor 4 for detecting a heating state of the wood 1 heated by the microwaves. A control circuit 5 for controlling the output of each microwave generator 3 by a signal from the wood sensor 4 is provided.

The shield case 2 is a box shape in which a slender rod-shaped lumber 1 such as a pillar or a log is hung vertically by a hanging conveyor 6 and can be transferred. It is made in. The shield case 2 shown in the figure has a height that allows long timbers and pillars to be transported in an upright posture, and a width that allows the timber 1 to be transported in two rows by a hanging conveyor 6 that forms a closed loop in a horizontal plane. It has a length such that a large number of wood pieces 1 can be hung and transferred. The length of the wood 1 such as pillars and logs to be dried is 3 to 8 m. Therefore, the height of the shield case 2 is 4 to 10 m. The width of the shield case 2 is about 1 to 5 m because the wood 1 is transferred in two rows. Furthermore, 100-5
The shield case 2 for suspending and transporting 00 rod-shaped wood pieces 1 has a total length of 10 to 30 m.

A part of the shield case 2 is opened in order to carry in and take out the wood 1, and this opening is closed by a shield shutter 7. The shield shutter 7
In the opened state, the wood 1 can be supplied to the suspension conveyor 6 of the shield case 2, and the dried wood 1 can be discharged from the suspension conveyor 6 to the outside. When the shield shutter 7 is closed, it is shielded and blocked so that microwaves do not leak from the opening of the shield case 2. The shield case 2 in the figure is provided with a shield shutter 7 with its left end opened. The shield shutter 7 is moved in the left-right direction by a cylinder (not shown) or the like to open and close the opening of the shield case 2.

The shield case 2 shown in FIG. 3 has a shield plate 8 disposed therein, and a shield region 10 in which the wood 1 is shielded from microwave irradiation and a microwave is applied to the wood 1 inside the shield case 2. And a microwave irradiation region 9 for irradiating with. Shield case 2 in this figure
Has a shield plate 8 extending vertically and arranged vertically. The shield plate 8 is disposed substantially in the center of the shield case 2, and one side of the shield case 2 is provided with the shield region 1.
0 and the other side is the microwave irradiation area 9.
The microwave generator 3 is not fixed to the shield area 10, and the microwave generator 3 is provided only in the microwave irradiation area 9. The microwaves emitted from the microwave irradiation area 9 are reflected by the shield plate 8 to shield the wood 1 passing through the shield area 10 from the microwaves. Therefore, in the shield case 2, the suspension conveyor 6
The wood 1 transferred by is heated by microwaves when passing through the microwave irradiation area 9, and is not heated by microwaves when passing through the shield area 10.

However, since the shield plate 8 does not completely shield the microwaves, the wood 1 passing through the shield region 10 is also irradiated with weak microwaves in a dense manner. However, the weak microwave does not overheat the wood 1, and the temperature of the wood 1 passing therethrough is lowered to allow the contained water to flow down along the conduit. Therefore, in the present specification, the shield region is not specified as one that completely radiates the microwave applied to the wood. The shield area is
This is because a weak microwave may be emitted.

The shield case 2 shown in FIG.
Is not installed. The shield case 2 controls the output of the microwave generator 3 to adjust the microwaves applied to the wood 1.

The shield case 2 has a hanging conveyor 6 horizontally arranged at the upper part thereof in order to suspend and transfer the wood 1 vertically. The hanging conveyor 6 is an endless chain,
A chain drive mechanism and a chain guide that horizontally disposes the chain are provided. The chain connects suspending tools for suspending the wood 1 at predetermined intervals. Chain 1
1 and the chain guide 12 are shown in the cross sectional view of FIG. The chain 11 in this figure has wheels 11B connected to both ends of a roller shaft 11A so as to be rotatable. Wheel 1
1B rolls on the inner surface of the chain guide 12, which is C-shaped steel, to smoothly move the chain 11 along the chain guide 12.

The roller shaft 11A of the chain 11 is connected to the upper end of the hanging tool 13. The hanging tool 13 includes a main body 13A connected to the roller shaft 11A, and the main body 1
Suspended part 1 rotatably connected to 3A in a horizontal plane
3B and. The hanging portion 13B has an upper end connected to the main body portion 13A via a pin 14. The pin 14 is vertically screwed and connected to the lower end of the main body 13A.

Further, the hanging conveyor 6 is provided with a rotating mechanism 23 for rotating the wooden piece 1 to be hung and transferred. The rotating mechanism 23 shown in the figure is a gear 1 fixed to the hanging portion 13B.
5 and a rack 16 arranged on the side surface of the shield case 2 so as to mesh with the gear 15. Gear 15
Is fixed to the upper portion of the hanging portion 13B in a horizontal posture. The rack 16 is horizontally extended and fixed to the side surface of the shield case 2. The rack 16 is fixed to the inner surface of the shield case 2 that linearly moves the chain 11 continuously or partially intermittently.
When the chain 11 is moved, the rotating mechanism 23 having this structure rotates the gear 15 fixed to the hanging portion 13B by meshing with the rack 16 and rotating the hanging portion 13B. The rotating hanging portion 13B rotates the suspended wooden piece 1 about the vertical axis.

The rotation cycle in which the rotating mechanism 23 rotates the wooden piece 1 is determined by the number of teeth of the gear 15 and the moving speed of the chain 11. For example, when the number of teeth of the gear is reduced and the moving speed of the chain is increased, the rotation cycle of the wood is reduced. On the other hand, if the number of teeth of the gear is increased and the chain is moved slowly, the rotation cycle of the wood becomes large.
Therefore, the rotation mechanism 23 adjusts the moving speed of the chain 11 and the number of teeth of the gear 15 to be optimum. The rotating mechanism 23, for example, takes 1 minute to rotate the wood 1 once.
Adjust so that it is 1 hour.

The hanging portion 13B is a connecting portion 1 at the upper end of the wood 1.
Connected to 7. The connecting portion 17 of the wooden piece 1 shown in the drawing is a U metal fitting that is fixed to the upper end surface of the wooden piece 1 by hammering. The connecting portion 17 has its tip driven into the wood 1 to be fixed, and is connected to the hook-shaped hanging portion 13B of the hanging tool 13. The connecting portion 17 has a shape in which a thick metal rod is bent in U and both ends thereof can be driven into the wood 1. Wood 1
As shown in FIG. 7, it is possible to provide a connecting portion 17 having grooves 17A on both sides of the upper end portion. The hanging part 13B connected to the connecting part 17 of this structure has a pair of arms 18 that can be opened and closed, and the lower end of the arm 18 is put in the groove 17A.
The upper end of the timber 1 is clamped and suspended.

The distance between the hanging tools 13 connected to the chain 11 is about 20 to 50 cm. This spacing should be longer than the contour of the thickest wood to dry. This is because the wood is hung and transferred while rotating in a horizontal plane.

Although not shown, the drive mechanism of the chain 11 includes a sprocket that meshes with the chain 11, a motor that rotates the sprocket, and a speed reduction mechanism that connects the motor to the sprocket. The drive mechanism moves the chain 11 at a speed such that one cycle of the chain 11 is preferably about 2 hours. As shown in the figure, the drying device that divides the inside of the shield case 2 into the shield region 10 and the microwave irradiation region 9 has a moving speed of the chain 11 and the time of the microwave irradiation step of irradiating the wood 1 with microwaves. And the time of the microwave interruption process in which the microwave irradiation is not performed can be adjusted. For example, in a drying device in which the chain 11 makes one turn, that is, one cycle of the chain 11 is 2 hours, the microwave irradiation step and the microwave interruption step can each be 1 hour. This is because the time for the wood 1 to pass through the microwave irradiation area 9 is one hour, and the time for the wood 1 to pass through the shield area 10 is one hour.

In the drying of wood, the time for interrupting the microwave irradiation and transferring the moisture inside the wood to the surface is 1 to
Two hours is optimal. Therefore, as shown in FIG.
The structure in which the shield region 10 is provided in a part of the shield case 2 has a time period of 1 to 1 for the wood 1 to pass through the shield region 10.
Ideally, the moving speed of the chain 11 is determined so as to be two hours. However, for the wood 1, the time of the microwave interruption process for interrupting the microwave irradiation is, for example, 10 times.
It can be dried for 10 minutes to 10 hours, preferably 20 minutes to 6 hours, and more preferably 30 to 3 hours. Therefore, in the apparatus of FIG. 3, the time for the wood 1 to pass through the shield area 10 is 10 minutes to 10 hours, preferably 2 minutes.
It is also possible to determine the speed of the chain 11 so as to be 0 minutes to 6 hours, more preferably 30 to 3 hours. If the time for interrupting the microwave irradiation is shorter than 10 minutes, the moisture pressurized inside cannot be effectively transferred to the surface,
On the other hand, if the time during which microwave irradiation is not performed exceeds 10 hours, the time required for drying becomes long.

The drying device shown in FIG. 3 has a shield case 2
The inside of is divided by the shield plate 8 into one shield region 10 and one microwave irradiation region 9. The shield plate is divided into a plurality of shield regions and a plurality of microwave irradiation regions. You can also do it. In this drying device, when a chain of wood is wrapped around a shield case, the wood passes through a plurality of shield areas and a microwave irradiation area. Therefore, it takes less time to pass through one shield region. Therefore, the drying device that divides the inside of the shield case into a plurality of shield regions and a microwave irradiation region specifies the chain transfer speed so that the time for the wood to pass through one shield region is the time described above. To do.

In the drying device of FIG. 4, the inside of the shield case 2 is not divided into the shield region 10 and the microwave irradiation region 9, but the whole is the microwave irradiation region 9. This drying device stops the output of the microwave generator 3 and interrupts the microwave irradiation of the wood 1. The device in this figure does not specify the time at which the microwave irradiation is interrupted at the transfer speed of the chain 11. This is because the time when the microwave generator 3 stops outputting microwaves can specify the time when the microwave irradiation is interrupted. Therefore, this device can efficiently dry the wood 1 by setting the speed of the chain 11 to a speed at which the wood 1 can be transferred in an ideal state.

In the drying device shown in FIGS. 3 and 4, when the timer is set to the drying time of the wood 1 and the timer is set up, the output of the microwave generator 3 can be stopped to dry the wood 1. However, preferably, the wood sensor 4 detects the heating state of the wood 1 heated by microwaves, the wood sensor 4 controls the microwave output to be turned on and off, or the average output is continuously controlled to dry. You can also The drying device that controls the output of the microwave generator 3 with the wood sensor 4 controls the output of the microwave while the wood 1 is heated. Therefore, in the device of FIG. 3, the output of the microwave generator 3 is turned on and off. The wood 1 passing through the microwave irradiation area 9 can be controlled so that the wood 1 is not irradiated with the microwave. Therefore, in the device of FIG. 3, the time for interrupting the microwave irradiation can be made shorter than the time for the wood 1 to pass through the shield region 10. Therefore, the wood 1 can be transferred slowly and slowly to shorten the time of the microwave interruption process. Further, in the apparatus shown in FIG. 4, the average output of the microwave generator 3 can be controlled so that the wood 1 can be dried while being continuously irradiated with microwaves so as not to be heated.

The chain guide 12 is a shield case 2.
Is installed horizontally on the ceiling of the. Illustrated chain guide 1
2 has a closed loop shape in which both ends of two straight line portions are connected by a semicircle. The chain guide 12 is C-shaped steel having a slit 12A opened on the lower surface. The chain guide 12 moves the chain 11 inward, and causes the hanging tool 13 to project to the outside from the slit 12A.

As shown in FIG. 3, the plurality of microwave generators 3 are fixed to the vertical surface of the shield case 2 so as to be separated from each other in the vertical direction with respect to the transfer direction of the wood 1. The microwave generators 3 are arranged at intervals so that the wood 1 passing through the microwave irradiation area 9 of the shield case 2 can be uniformly irradiated with microwaves. Microwave generator 3 to shield case 2
The microwave radiated therein is reflected by the inner surface of the shield case 2 and the shield plate 8 to uniformly heat the wood 1.
The center interval of the openings of the waveguide through which the microwave generator 3 radiates microwaves to the shield case 2 is, for example, 30.
-100 cm. The wood 1 can be dried more uniformly by narrowing the interval between the adjacent waveguides. Further, if the interval between the waveguides is widened, interference of microwaves radiated from the adjacent microwave generators 3 can be reduced.

As shown in FIG. 8, each microwave generator 3 includes a magnetron 31 for generating a microwave, a waveguide 30 for supplying the microwave generated by the magnetron 31 to the shield case 2, and a magnetron. The plate 31 includes a high-voltage power supply 32 that supplies a high-voltage direct current, and a heater power supply 33 that heats a heater. Each microwave generator 3 preferably comprises a magnetron 31, a high voltage power supply 32 and a heater power supply 33 respectively, but the heater power supply can also be designed to supply heater power to a plurality of magnetrons. . For example, the heater power source is common to all microwave generators, and one unit can supply heater power to all magnetrons.

Each microwave generator 3 is equipped with a magnetron 31 and a high voltage power source 32,
The average output of each microwave generator 3 can be adjusted independently. Therefore, the wood 1 can be dried in a more ideal environment. The microwave generator 3, which can control the output independently,
For example, the output of the microwave generators 3 arranged on the upper and lower portions of the shield case 2 can be controlled to be small to uniformly dry the entire wood 1.

The magnetron 31 has a frequency of 2 to 4 GHz from the side surface inside the shield case 2 via the waveguide 30.
Is applied, for example, a microwave of 2450 MHz is irradiated. The waveguide 30 is horizontally opened on the vertical surface of the shield case 2 to irradiate the wood 1 with microwaves. The high voltage power supply 32 is 100 or 200 to be input.
A commercial power source of V is boosted by a transformer, and the alternating current on the secondary side of the transformer is rectified into a direct current of 2000 to 4000 V and supplied to the magnetron 31. The heater power supply 33 includes a transformer that steps down the input alternating current to the heater voltage of the magnetron 31. The magnetron 31 has a heater power supply 33.
When a high voltage is input from the high voltage power supply 32 while the heater is heated by the power supplied from the microwave, the microwave is oscillated and output from the waveguide 30.

This microwave generator 3 has a high voltage power source 32.
The output of the magnetron 31 can be controlled by the average voltage supplied from the magnetron 31 to the magnetron 31. If you lower the average voltage,
The output of the magnetron 31 decreases, and the output of the magnetron 31 increases as the average voltage increases. High voltage power supply 32
Can adjust the average voltage of the high-voltage power supply 32 by the electrostatic capacity of a capacitor connected to the secondary side of the transformer. Increasing the capacitance of the capacitor increases the average voltage, and decreasing the capacitance decreases the average voltage.

Further, in the microwave generator 3, a switch 34 for turning on / off the microwave output is connected to the input side or the output side of the high voltage power supply 32. When the switch 34 is turned on, the magnetron 31 enters an operating state and outputs microwaves. When the switch 34 is turned off, the microwave is not output. Therefore, the microwave output can be controlled by turning on / off the switch 34. Further, the switch 34 can be turned on and off in a short cycle to adjust the average output of microwaves. When the duty ratio of the on time to the off time is increased, the average output of microwaves increases. The switch 34 is turned on / off by the control circuit 5 to turn on / off the output of the magnetron 31.

The microwave output of the microwave generator 3 is
It is controlled by the control circuit 5. The control circuit 5 is the wood sensor 4
Alternatively, the microwave generator 3 is controlled by a timer. The wood sensor 4 is a sensor that detects the heating state of the wood 1, and preferably a temperature sensor that detects the temperature is used. The temperature sensor uses a non-contact infrared sensor to detect the moving wood temperature. The temperature sensor ideally detects the mouth temperature of the wood 1. This is because when the wood 1 is internally heated by microwaves, the pressurized steam is injected to the outside through the conduit, so that the temperature of the wood mouth where the steam is injected becomes the highest.

The control circuit 5 for controlling the output of the microwave generator 3 with the temperature sensor stops the output of the microwave generator 3 when the wood temperature reaches the set temperature or controls the output to be small. The drying device of FIG. 3 has a microwave irradiation area 9
A temperature sensor is provided in the to detect the temperature of the wood 1 passing therethrough. A plurality of temperature sensors are provided in the microwave irradiation area 9, or one temperature sensor is provided. A device that detects the temperature of wood with a plurality of temperature sensors controls the output of the microwave generator 3 by the signal of the temperature sensor that detects the maximum temperature. However, the output of the microwave generator can be controlled by the average value of the plurality of temperature sensors.

In the drying device of FIGS. 3 and 4, the control circuit 5 for controlling the output of the microwave generator 3 by the signal of the temperature sensor detects from the temperature sensor that the wood 1 has risen to the maximum temperature. When a signal is input, the microwave generator 3
Output is controlled to be off or the average output is controlled to be small. The control circuit 5 that controls the average output to be small by the signal of the temperature sensor reduces the average output so that the wood temperature does not reach the maximum temperature. The control circuit 5, which detects that the temperature of the wood reaches the maximum temperature and switches off the output of the microwave generator 3, detects by the temperature sensor that the temperature of the wood 1 has dropped to the set temperature, The output of the generator 3 is switched on. In addition, the output of the microwave generator 3 is switched on after the elapse of a predetermined time by the timer.

Further, the wood sensor 4 may be a smoke sensor for detecting smoke emitted from the wood 1. When the wood 1 is internally heated by microwaves, the internal temperature locally rises and smoke is generated inside. This smoke is injected outside the wood 1 through the conduit. The state in which smoke is ejected from the wood 1 is a state in which the internal temperature of the wood 1 is considerably high, so the smoke becomes a parameter for detecting that the interior of the wood 1 has been heated to a high temperature. Therefore, the smoke ejected from the wood 1 can be detected to control the output of the microwave generator 3.

In the drying device of FIGS. 3 and 4, the control circuit 5 for controlling the output of the microwave generator 3 by the signal of the smoke sensor detects that the smoke sensor detects smoke in the shield case 2.
The output of the microwave generator 3 is controlled to be off, or the average output is controlled to be small. The control circuit 5, which controls the average output to be small by the signal of the smoke sensor, reduces the average output so that smoke is not generated in the shield case 2.
Detecting smoke in the shield case 2 and microwave generator 3
The control circuit 5 for switching off the output of the microwave generator 3 detects that there is no smoke in the shield case 2 and
The output of the microwave generator 3 is turned on, or the output of the microwave generator 3 is turned on after a predetermined time has elapsed by the timer. Although not shown, the shield case 2 exhausts internal air with an exhaust fan that is continuously operating.
Therefore, even if smoke is spouted from the wood 1 into the shield case 2, if the output of the microwave generator 3 is turned off, the smoke is not spouted from the wood 1, so the smoke inside the shield case 2 is discharged. Disappears.

A control circuit 5 for controlling the output of the microwave generator 3 by both the wood sensor 4 such as a temperature sensor and the smoke sensor.
Is a microwave sensor 3 using a wood sensor 4 such as a temperature sensor.
When the smoke sensor detects smoke in the shield case 2, the output of the microwave generator 3 is turned off, and then the microwave generator 3 is held in the off state.

Further, the wood sensor 4 can detect the water content and the weight of the wood 1. The sensor for detecting the water content can directly detect the water content of the wood 1, or can measure the weight of the wood 1 and detect the water content from this weight. The water content sensor measures the water content of the wood 1 in close proximity to or in contact with the surface of the wood 1.
The water content sensor that contacts the surface of the wood detects the water content by contacting the surface of the wood in a state where the wood transferred by the hanging conveyor 6 is transferred to a fixed position. Hanging conveyor 6
Since the wood is slowly transferred, the water content is detected by pressing a water content sensor with a cylinder or the like onto the surface of the wood that has been transferred to a fixed position. As the moisture content sensor, a commercially available one can be used, for example, one that measures the electrical resistance or the dielectric constant of wood to detect the moisture content. The moisture content sensor approaches the surface of the wood when measuring the moisture content of the wood and when not measuring the moisture content of the wood,
Stand away from the wood.

Although not shown, the water content sensor is fixed to the tip of the inlet / outlet cylinder and is brought into contact with the surface of the wood. The loading / unloading cylinder has a water content sensor fixed to the tip of the rod so that the water content sensor approaches the wood from the outside of the shield case. Further, the shield case is provided with a through hole at a portion where the water content sensor comes in and out, and an opening / closing lid is provided here.

The above moisture content sensor detects the moisture content of wood as follows. (1) Temporarily stop the oscillation of the microwave generator 3. The microwave generator 3 turns off the high voltage power supply 32 to stop the oscillation. (2) The water content sensor is brought into contact with the surface of the wood 1 using the in / out cylinder. (3) The water content sensor detects the water content of the wood 1, and outputs the detected water content signal to the control circuit 5. (4) Extend and retract the inlet / outlet cylinder to pull the moisture content sensor away from the surface of the wood 1 and pull it out of the shield case 2. (5) After that, the through hole is closed so that the microwave does not leak from the shield case 2. (6) After that, the microwave 1 is applied to the wood 1 by the microwave generator 3.

The wood sensor 4 can also detect the weight of the wood 1. Weight sensor 19 for detecting the weight of the wood 1
Are shown in the plan view of FIG. 9 and the front view of FIG. The weight sensor 19 shown in these figures is used for the hanging tool 13 of the chain 11.
A pair of mounting bases 20 are provided on both sides where the
A sensor element 21 for detecting the weight is fixed to the platform 20. The weight sensor 19 includes a pair of mounts 20.
The suspending tool 13 is mounted on and the weight of the wood 1 is detected. When the hanging tool 13 is placed on the platform 20, the weight of the wood 1 is reduced by the platform 20.
Act on. Therefore, in this state, the weight of the table 20 can be detected by the sensor element 21 to detect the weight of the wooden piece 1. Since the mounting table 20 is arranged on both sides of the suspension 13, the gear 15 of the suspension 13 slides on the mounting table 20 when the suspension 13 moves between the mounting tables 20. While passing. That is, the suspension 13 is placed on the platform 20. The gear 15 mounted on the mounting table 20 has pins 14
The suspension 13 is connected to the main body 13A of the suspension 13 so that it can be moved up and down to some extent. Weight sensor 19 is wood 1
When the weight of the wooden piece 1 is detected, the movement of the hanging conveyor 6 can be temporarily stopped to detect the weight of the wooden piece 1 more accurately. In the state where the hanging conveyor 6 moves, the gear 15 moves the hanging tool 1
3 is pulled by the main body 13A, and this pulling force causes an error in detecting the weight of wood. When the suspension conveyor 6 is stopped, the gear 15 is no longer pulled by the main body 13A, and the weight of the wood 1 acts on the platform 20 to accurately detect the weight.

In the weight sensor 19 shown in FIGS. 9 and 10, the sensor elements 21 are fixed to the lower surfaces of both ends of the pair of mounts 20 located on both sides of the hanging tool 13. That is, the weight sensor 19 shown in these figures measures the weight of the wood 1 with the four sensor elements 21. This weight sensor 1
9 has a feature that the weight of the wood 1 can be detected more accurately. However, in the weight sensor 19, as shown in FIG. 11, one sensor element 21 may be provided on each of the lower surfaces of the central portions of the pair of mounts 20. This weight sensor 19
Has a feature that the cost can be reduced because the weight of the wood 1 is detected by the two sensor elements 21. Further, in the weight sensor 19 shown in this figure, one end of the platform 20 is connected to the rotary shaft 25.
And the other end is connected to the support plate 24 so as to be vertically movable. The support plate 24 to which the vertically moving ends of the mounting table 20 are connected has an elongated hole 24A opened in the vertical direction.
A guide protrusion 20A protruding from a side surface of the mounting table 20 is inserted inside the elongated hole 24A. This weight sensor 1
When the gear 15 is placed on the platform 20 and the load of the wood 1 is applied, the platform 9 tilts and the load acts on the sensor element 21 arranged in the central portion. Can be accurately detected.

Further, FIG. 12 shows a weight sensor 19 for detecting the weight of wood more accurately. This weight sensor 19
Fixes the platform 20 to the tip of the push-up cylinder 22. The sensor element 21 is fixed to the upper surface of the mounting table 20. In the weight sensor 19, when the suspending tool 13 moves above the sensor element 21, the push-up cylinder 22 slightly pushes up the platform 20, and the gear 15 of the suspending tool 13 is moved.
Is placed on the sensor element 21. Therefore, in this state, the suspending tool 13 is not suspended from the chain 11, and the entire weight of the wood 1 pushes down the sensor element 21 via the gear 15.

The weight sensor 19 detects the weight of wood by mounting the gear 15 of the hanging device 13 on the mounting table 20. However, a member for mounting the mounting tool on the mounting tool is provided on the hanging device, or the weight of the wood is detected. The connecting portion fixed to the upper end may be provided with a holding portion to be mounted on the mounting table. In the structure in which the upper part of the wood is provided, it is not always necessary to connect the gear and the hanging part so that they can be moved up and down to some extent. Because there is play that can be moved up and down a little between the hanging part and the connecting part of the wood, it is possible to hang the entire weight of the wood from the upper part to the mounting base while the lifting part is placed on the mounting base. .

The weight sensor 19 is, for example, as shown in FIGS.
As shown in the plan view of FIG. 1, it is arranged inside the shield case 2 and near the entrance and exit of the wood 1. In the drying device shown in the figure, two weight sensors 19 are arranged in the vicinity of the shield shutter 7 which is the entrance and exit of the wood 1. One of the two weight sensors 19 is arranged on the supply side of the wood 1, and the other is arranged on the discharge side of the wood 1. The weight sensor 19 arranged on the supply side of the wood 1 detects the weight of the wood 1 before it is dried by making one round in the shield case 2. The weight detected here is input to the control circuit 5 as the initial weight of the wood. Weight sensor 19 arranged on the discharge side of the wood 1
Detects the weight of the dried wood that makes one round in the shield case 2. The weight detected here is input to the control circuit 5 as the dry weight of wood. The control circuit 5 stores, for example, the weight of wood for each hanging tool, and based on the difference between the initial weight input from the weight sensor 19 and the dry weight,
The amount of water reduction, which is the amount of water removed, is calculated. In particular, it is possible to detect the amount of water reduction that is removed while the wood makes one round in the shield case 2.

The control circuit 5 determines from the weight input from the weight sensor 19 whether the wood 1 is dried. In the control circuit 5, for example, the weight of the wood when the drying is finished is set as a dry finish weight region having a certain width. The control circuit 5 includes a weight sensor 1
The dry weight detected in 9 is compared with this dry end weight region to determine the dry state of the wood. The dry end weight region is a weight region determined by the type, shape, size, etc. of wood, and is calculated in advance and input to the control circuit. However, the dry end weight region can be calculated and set from the initial weight when wood is supplied into the shield case. If the dry weight of the wood is within this area, the control circuit 5 determines that the wood has been dried to a predetermined weight, discharges it from the shield case 2, and finishes the drying.
The dried wood, after stopping the microwave generator 3,
The shield shutter 7 is opened and the sheet is discharged. The discharge of the wood can be performed by controlling the control circuit 5 or can be performed by the operator directly by hand. Further, at this time, the wood that has not been dried to a predetermined weight is transported once more for drying without being discharged. However, even if the timber has not been dried to a predetermined weight, the amount of water loss when it is transported by one more round and dried causes
If it can be estimated that the product will be dried to a predetermined weight or less, it is discharged without being transferred and the drying is completed. This is to prevent overdrying of wood.

In the above drying apparatus, the weight sensors 19 are arranged on the supply side and the discharge side of the wooden piece 1, respectively. Although not shown, the weight sensor may be provided only on the wood supply side or the wood discharge side to determine the dry state of the wood. The weight sensor can calculate the amount of water reduction removed during one round in the shield case from the weight detected last time and the weight detected this time. The drying device in which the weight sensor is provided only on the discharge side compares the detected weight with the dry end weight region to determine the dry state of the wood.
Further, the drying device in which the weight sensor is provided only on the supply side estimates the weight of the wood after one round of transfer from the amount of water decrease, compares the estimated weight of the wood with the dry end weight region, and Determine the dry state.

Further, the control circuit 5 controls the output of the microwave generator 3 with the output of the weight sensor 19, or
An arithmetic circuit converts the weight of the wood 1 detected by the weight sensor 19 into a water content, and the output of the microwave generator 3 is controlled by the water content. The calculation circuit for calculating the water content from the weight of the wood subtracts the weight (W) of the wood detected by the weight sensor 19 from the weight of the wood, that is, the weight (W ₀ ) in the completely dry state, to subtract the weight of the wood. The water content (x) is calculated, and the ratio of the water content (x) to the absolutely dry weight (W ₀ ) is calculated as the water content. That is, the water content of wood is calculated by the following formula. Moisture content [%] = x / W ₀ × 100 (where x = W−
W ₀ )

The weight (W ₀ ) of the absolutely dried wood can be obtained by multiplying the volume (V) of the dried wood by the specific gravity (ρ) of the completely dried wood. The volume of wood can be calculated, for example, from the length and the total length of the vertical and horizontal sides of the cross section in the case of timber, and from the diameter and the total length in the case of raw wood. Since the specific gravity (ρ) in the absolutely dry state varies depending on the type of wood, it is input into the arithmetic circuit for each type such as cedar, pine, cypress, etc. In the above moisture content detector, when the wood is dried, the size and type of the wood are input to the arithmetic circuit, and the weight (W
₀ ) is calculated by the arithmetic circuit. In addition, the moisture content detector
Calculated weight of absolutely dry wood calculated by the arithmetic circuit (W ₀ ).
And the water content (W) of the wood detected by the weight sensor 19, the water content of the wood is calculated. The water content detector of this structure is
The moisture content of the whole wood can be detected.

The control circuit 5 for controlling the water content of the wood 1 detected by the water content sensor or the weight sensor 19 or the output of the microwave generator 3 by the weight of the wood 1 uses the water content of the wood 1 as a parameter, or The microwave output is controlled using the weight as a parameter. The drying device of FIG. 3 or FIG. 4 provided with this control circuit 5 continuously controls the average output of the microwave output to dry the wood 1, or switches the microwave output on and off to perform the microwave irradiation step. Wood 1 repeating the microwave interruption process
To dry.

FIG. 13 shows a state in which the control circuit 5 for drying the wood 1 by continuously changing the microwave output controls the microwave output. This control circuit 5 linearly controls the output of microwaves in a predetermined range of the water content of the wood 1, and when the water content of the wood 1 is greater than the predetermined water content, the microwave is maximized. Further, when the wood 1 is dried to a predetermined water content, the microwave output is set to 0, that is, the microwave is not irradiated. As shown in FIG. 14, the control circuit 5 controls the microwave output stepwise in a predetermined range of the water content of the wood 1, and when the water content of the wood 1 is higher than the predetermined water content, It is also possible to set the wave to the maximum output and, when the wood 1 is dried to a predetermined water content, set the microwave output to 0, that is, not to irradiate the microwave.

In the drying device of FIG. 3, since the wood 1 is not irradiated with the microwave in the shield area 10, the microwave output applied to the wood 1 in the microwave irradiation area 9 is controlled by the control circuit 5.

When the control circuit 5 controls the microwave output to dry the wood 1 as shown in FIGS. 13 and 14,
The water content of the wood 1 decreases with time and is dried. At first, since the microwave output is large, the water content of the wood 1 is rapidly reduced. When the microwave output is linearly or stepwise reduced, the decrease in the water content of the wood 1 gradually decreases. When the wood 1 is dried to a predetermined water content, the microwave output becomes 0 and the water content of the wood 1 does not change. The water content at which the microwave output is 0 is the water content obtained by drying the wood 1 to a predetermined water content.

The control circuit 5 may control the microwave output so that the water content of the wood 1 decreases first and then decreases gradually, or the water content of the wood 1 decreases linearly. it can. Also in the method of reducing the water content of the wood 1 in this way, when the wood 1 is dried to a predetermined water content, the microwave output is set to 0 and the irradiation of microwaves is stopped.

The control circuit 5 for detecting the water content of the wood 1 and controlling the microwave output, when the water content of the wood 1 becomes larger than the value indicated by the memory function stored in advance,
The microwave output is increased to bring the moisture content of wood 1 closer to the memory function. When the water content of the wood 1 becomes smaller than the value indicated by the memory function, the microwave output is decreased,
The moisture content approaches the memory function.

The simplest control circuit 5 controls so that the microwave outputs of the plurality of microwave generators 3 become the same. The control circuit 5 that controls the microwave outputs of the plurality of microwave generators 3 by the plurality of wood sensors 4 can also separately and independently control the microwave outputs of the respective microwave generators 3.

The above control circuit 5 is the wood sensor 4 for detecting the water content and the weight, and continuously changes the microwave output.
It is also possible to switch the output of ON / OFF, that is, to perform drying in the microwave irradiation step and the microwave interruption step. This drying device stores the moisture content and the weight for switching off the microwave output as a plurality of set values, or the variation values of the moisture content and the weight for switching off the output of the microwave generator 3. is doing.

The drying device shown in FIGS. 3 and 4 having the control circuit 5 storing a plurality of set values is a microwave generator when the moisture content or the weight of the wood 1 decreases to the set value. Turn off the output of 3. After that, when the set time of the timer has elapsed, the microwave generator 3 is turned on again. Further, the control circuit 5 which stores the change values of the water content and the weight changes the control circuit 5 when the wood 1 is dried and the water content and the weight change to the stored change values.
Switches off the output of the microwave generator 3. After that, when the set time of the timer has elapsed, the microwave generator 3 is switched on.

The drying device dries the wood in the following steps. (1) Method for Drying Wood without Using Wood Sensor The drying apparatus shown in FIG. 3 irradiates the wood 1 passing through the microwave irradiation area 9 with microwaves and the wood 1 passing through the shield area 10 with microwaves. The wood 1 is dried without irradiation. The microwave generator 3 is switched off by the control circuit 5 after the time for drying the wood 1 elapses. Wood loading process The shield case 2 is opened and the wood 1 is supplied to the hanging conveyor 6. At this time, the microwave generator 3 is held in the off state. The hanging conveyor 6 transfers the wood 1 to the hanging tool 13 and supplies the wood 1 to the next hanging tool 13. When the wooden pieces 1 are supplied to all the hanging tools 13, the shield case 2 is closed to prevent microwaves from leaking. The microwave generator 3 is switched on, and the wood 1 passing through the microwave irradiation area 9 is irradiated with microwaves. The wood 1 transported by the suspension conveyor 6 inside the shield case 2 passes through the microwave irradiation area 9, and is a microwave irradiation step, and when passing through the shield area 10, the microwave interruption step. Therefore, the wood 1 is dried by repeating the microwave irradiation step and the microwave interruption step. In the microwave irradiation step, the wood 1 is heated from the inside. Therefore, the wood 1 has a high internal temperature and a low surface temperature. Further, since water is quickly removed from the surface, the surface has a low water content and the inside has a high water content. Then, in the microwave interruption step in which the irradiation of microwaves is interrupted, water flows down from the inside at high temperature and high pressure along the conduit and is transferred to the surface. When the water is transferred to the surface, the water content of the wood 1 becomes uniform, and the internal pressure and temperature decrease. The internal pressure is lowered by discharging the internal moisture, and the internal pressure is lowered, the boiling point of water is lowered, the water is quickly vaporized, and the water is vaporized to cool the interior of the wood 1 by the heat of vaporization. This is because that. The microwave irradiation step and the microwave interruption step are repeated to reduce the water content of the wood 1 and dry it to a predetermined water content. When the wood 1 is dried, the microwave generator 3 is turned off, the shield case 2 is opened, and the wood 1 is taken out.

In the above drying method, the wood 1 can be dried without using a timer, but the temperature sensor, the water content sensor, and the smoke sensor detect that the wood 1 has been dried to a predetermined moisture content, and The wave generator 3 can also be stopped.

The drying apparatus shown in FIG. 4 can dry the wood 1 in a state where the microwave irradiation step and the microwave interruption step are repeated by setting the time for turning on and off the microwave generator 3 with a timer. . The timer also stores the time when the wood 1 dries, and when this timer is set up and the wood 1 dries, the microwave generator 3 is stopped. Also in this drying method, it is possible to stop the microwave generator 3 by detecting the drying of the wood 1 with the wood sensor 4.

(2) Method of Drying Wood by Using Wood Sensor while Control Circuit Controls Microwave Generator Using Wood Sensor Signal The drying apparatus shown in FIG. Even in the method of controlling the microwave generator 3, the wood 1 passing through the microwave irradiation area 9 is irradiated with microwaves, and the wood 1 passing through the shield area 10 is not irradiated with microwaves. However, since the control circuit 5 controls the output of the microwave generator 3, the wood 1 passing through the microwave irradiation area 9 is not necessarily irradiated with microwaves.
This is because the heating state of the wood 1 is detected by the wood sensor 4 and the microwave generator 3 is controlled. Therefore, the wood 1 passing through the microwave irradiation region 9 is irradiated with the microwave at the rated output, or is irradiated with the microwave whose average output is adjusted to be small, or is not irradiated with the microwave. However, the wood 1 passing through the shield region 10 is not irradiated with microwaves, and in this step, the water content inside flows down along the conduit.

In the drying device shown in FIG. 4, the entire inside of the shield case 2 is used as the microwave irradiation area 9. This drying device is a method of drying while continuously adjusting the average output of microwaves by the control circuit 5, and a method of drying the wood 1 transferred by the hanging conveyor 6 by repeating the microwave irradiation step and the microwave interruption step. There is a method of drying. The method of continuously controlling the average output of microwaves is to detect the temperature of the wood with a temperature sensor and control the microwave output so that the wood 1 does not become abnormally high, or, as shown in FIGS. 13 and 14, The wood 1 is dried by controlling the microwave output with the water content as a parameter, or by controlling the microwave output so that the water content and the weight decrease according to the stored function.

In the drying apparatus shown in FIG. 4, the microwave generator 3 is switched on and off, and the wood 1 is dried by repeating the microwave irradiation step and the microwave interruption step. The microwave generator 3 is switched on and off by the signals of the wood sensor 4 and the timer, and the microwave irradiation step and the microwave interruption step are repeated to dry the wood 1.

The drying apparatus shown in FIG. 4 switches the microwave generator 3 on and off to dry the wood 1 by repeating the microwave irradiation step and the microwave interruption step. There is a method of switching on and off together, and a method of dividing the plurality of microwave generators 3 into a plurality of blocks and separately switching on and off the microwave generators 3 of the respective blocks.

The method of separately turning on / off the microwave generators 3 of a plurality of blocks is to turn on / off the microwave generators 3 of each block in synchronization with the transfer of the wood 1 to the hanging conveyor 6. Switch. This method
For example, the microwave generator 3 can be switched on or off as the wood 1 is transferred,
The time of the microwave irradiation step and the microwave interruption step can be set regardless of the transfer speed of the suspension conveyor 6. In this method, the heating state of each piece of wood 1 is independently detected by the wood sensor 4, or the entire wood piece is divided into a plurality of blocks, and the heating state of the divided piece of wood 1 is detected by the wood sensor 4. It is also possible to sequentially switch off the microwave generators 3 of the wood through which the irradiation of microwaves needs to be stopped, or the portions through which the blocks pass. Therefore, according to this method, the wood can be partially carried into the shield case 2 and all the wood can be dried in an ideal state.

[0083]

The drying method according to claim 1 and claim 6 of the present invention.
The drying device has a feature that thick and heavy logs and timbers can be straightened and dried without bending. This is because the wood heated by the microwave is vertically hung and not transferred, and the wood is dried by the microwave. In addition to heating wood from the inside, the microwave heats and heats the wood itself, so that the heating temperature has no upper limit in principle. Therefore, the temperature of the wood heated and dried by the microwave becomes extremely high, and the wood is softened and easily deformed. The present invention utilizes this state to prevent the bending of the wood and further has the function of straightening the bent wood that has advanced by its own weight.

Furthermore, the drying method according to claim 1 and the drying device according to claim 6 of the present invention irradiate microwaves while drying the wood while suspending and transporting it, so that a large amount of wood can be efficiently dried together. . This is because the wood is hung vertically and irradiated with microwaves, so that the water inside the wood heated to high temperature and high pressure by the microwaves can be quickly discharged to the outside along the vertical conduit. Furthermore, since a long piece of wood is hung vertically, the horizontal area is extremely small, and a large amount of wood can be loaded into a device with a small installation area and can be dried together efficiently.

Furthermore, the drying method according to claim 1 and the drying device according to claim 6 of the present invention, while minimizing the cracking of wood,
It has the feature that it can evenly and quickly dry the entire wood. It suspends the wood vertically and irradiates it with microwaves, so that the high temperature and high pressure water is smoothly discharged along the vertical conduit to prevent the wood from bulging due to the rise in internal pressure. In addition, the moisture can be quickly discharged to shorten the drying time.

Furthermore, a remarkable feature of the drying method according to claim 1 and the drying device according to claim 6 of the present invention is that a large number of woods can be uniformly irradiated with microwaves to be efficiently dried. The drying method and the drying apparatus of the present invention irradiate the wood transported by the hanging conveyor with microwaves from the side surface, and transport the hanging wood while rotating it about the vertical axis for drying. In this way, the wood that is transported while rotating on its axis is dried while the portions irradiated with strong microwaves and the portions irradiated with weak microwaves are changed by rotation. In particular, when the portion heated to a high temperature by the strong microwave is irradiated with the weak microwave by the rotation of the wood, the moisture heated to the high temperature and the high pressure is transferred to the surface. Therefore, it is possible to uniformly heat the entire wood while smoothly transferring the moisture heated inside the wood to the surface. This is also very effective in minimizing the cracking of wood.

In the drying method according to claim 3 and the drying device according to claim 11 of the present invention, the wood is repeatedly dried in the microwave irradiation step and the microwave interrupting step. Water that has been heated and pressurized by is flowed down a vertical pipe and smoothly transferred to the surface for discharge, and then the water is transferred from the inside of the wood with a high water content to the surface to make the entire water content uniform. Turn into. Therefore, in the microwave interruption step, the water content inside the wood is discharged more quickly, and the internal pressure is rapidly decreased. For this reason, cracking of the wood is more effectively prevented.

Furthermore, in the drying apparatus according to the tenth aspect of the present invention, the inside of the shield case is divided into a shield area for shielding microwave irradiation by a shield plate and a microwave irradiation area for microwave irradiation. Since the wood is dried while being transferred to the shield area and the microwave irradiation area, the moisture inside the wood heated to a high temperature in the microwave irradiation area is made to flow down the vertical conduit in the shield area and is smoothed. The water content can be made uniform by moving to the surface and discharging. This drying device can also quickly drain the water inside the wood and quickly reduce the internal pressure, so that cracking of the wood can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a wood drying device developed by the present inventor.

2 is a cross-sectional view of the drying device shown in FIG.

FIG. 3 is a plan view of a wood drying apparatus according to an embodiment of the present invention.

FIG. 4 is a plan view of a wood drying apparatus according to another embodiment of the present invention.

5 is a front view of the wood drying apparatus shown in FIG.

FIG. 6 is an enlarged cross-sectional view showing a state where the hanging conveyor suspends wood.

FIG. 7 is a cross-sectional view showing another example of a suspender for suspending wood.

FIG. 8 is a schematic configuration diagram of a microwave generator.

FIG. 9 is a plan view showing a weight sensor for detecting the weight of wood.

FIG. 10 is a front view of the weight sensor shown in FIG.

FIG. 11 is a plan view showing another example of a weight sensor for detecting the weight of wood.

FIG. 12 is a front view showing another example of a weight sensor for detecting the weight of wood.

FIG. 13 is a graph showing an example of controlling the microwave output by the water content of wood.

FIG. 14 is a graph showing another example of controlling the microwave output by the water content of wood.

FIG. 15 is a schematic horizontal sectional view showing a state in which wood is irradiated with microwaves.

[Explanation of symbols]

1 ... Wood 2 ... Shield Case 3 ... Microwave Generator 4 ... Wood Sensor 5 ... Control Circuit 6 ... Hanging Conveyor 7 ... Shield Shutter 8 ... Shield Plate 9 ... Microwave Irradiation Area 10 ... Shield Area 11 ... Chain 11A ... Roller Axis 1
1B ... Wheel 12 ... Chain guide 12A ... Slit 13 ... Hanging tool 13A ... Main body 1
3B ... Suspended part 14 ... Pin 15 ... Gear 16 ... Rack 17 ... Connection part 17A ... Groove 18 ... Arm 19 ... Weight sensor 20 ... Mounting stand 20A ... Guide protrusion 21 ... Sensor element 22 ... Pushup cylinder 23 ... Rotation mechanism 24 ... Support Plate 24A ... Slot 25 ... Rotating shaft 30 ... Waveguide 31 ... Magnetron 32 ... High voltage power supply 33 ... Heater power supply 34 ... Switch 35 ... Roller 36 ... Antenna

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-14251 (JP, A) JP-A-62-178875 (JP, A) JP-A-11-512513 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F26B 3/347 B27K 5/00 F26B 15/00 F26B 15/12

Claims (11)

(57) [Claims] 1. A method for drying wood (1) by irradiating it with microwaves, the wood (1) being hung by a hanging conveyor (6) so that the conduit is in a vertical direction, and transferred. Irradiate microwaves from the side to the wood (1) transferred by the hanging conveyor (6), and further the wood (1) transferred by the hanging conveyor (6)
Is a method for drying wood that rotates while rotating about the vertical axis. 2. The rotation time of the rotating wood (1) is 1
The method for drying wood according to claim 1, which is from minutes to 1 hour. 3. The microwave irradiation step of irradiating the wood (1) with microwaves, and the microwave interruption step of interrupting the microwave irradiation of the wood (1) are repeated for drying.
The method for drying wood described in. 4. The wood sensor according to claim 1, wherein any one of temperature, water content and weight of the wood (1) is detected by a wood sensor (4), and the microwave output is controlled by a signal of the wood sensor (4). Method of drying wood. 5. A wood sensor (4) for detecting smoke generated from the wood (1).
The method for drying wood according to claim 1, wherein the microwave output is detected by the method described above, and the output of the microwave is controlled by the output of the wood sensor (4). 6. A shield case (2) for containing dry wood (1), a hanging conveyor (6) for suspending and transferring a plurality of wood (1) in the shield case (2), and this shield A plurality of microwave generators (3) for irradiating microwaves from the side surface of the case (2) toward the internal wood (1) are provided, and the plurality of microwave generators (3) include a hanging conveyor (6 ) Is wood
(1) is placed in a predetermined distance away from the direction of transfer, irradiates the transferred wood (1) with microwaves, and the hanging conveyor (6) hangs the transferred wood. (1)
, Is equipped with a rotation mechanism (23) that rotates about the vertical axis, and the hanging conveyor (6) transfers the wood (1) while rotating it with the rotation mechanism (23). Microwave Generator (3)
A wood drying device in which the side is irradiated with microwaves and dried. 7. A wood sensor (4) for detecting the heating state of the wood (1) in the shield case (2), the wood sensor (4)
7. The wood drying apparatus according to claim 6, wherein the microwave generator (3) is controlled by the. 8. The wood sensor (4) is a sensor for detecting one of the temperature, water content and weight of the wood (1).
The wood drying apparatus described in 1. 9. The wood drying apparatus according to claim 7, wherein the wood sensor (4) is a smoke sensor for detecting smoke generated from the wood (1). 10. A shield plate (8) is disposed on the shield case (2), and the shield plate (8) is a shield case.
(2) Shield area where microwave irradiation is shielded
(10) and the microwave irradiation area where the microwave is irradiated
The wood according to claim 6, which is partitioned into (9) and the hanging conveyor (6) transfers the wood (1) to the shield area (10) and the microwave irradiation area (9) for drying. Drying equipment. 11. The microwave generator (3) is controlled to irradiate the wood (1) transferred by the hanging conveyor (6) with microwaves for a certain period of time and stop irradiation of microwaves for a certain period of time. 7. A wood drying device according to claim 6, further comprising a control circuit (5) for limiting.