JP2923266B2 - Wood drying equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for drying pillars and logs using microwaves.

[0002]

2. Description of the Related Art When wood is used in an undried state,
Various adverse effects such as a large deformation with time or a contraction to form a gap occur. This adverse effect can be effectively prevented by drying and using the wood. The most common method of drying wood is to leave the wood unattended, but this method has the disadvantage of being extremely time consuming. As a method of drying wood in a single time, a method of heating wood with steam or high frequency has been put to practical use. In the method of heating with steam, the wood is heated to 100 ° C. or more in order to boil and remove moisture contained in the wood in a short time. For this purpose, wood is put into a pressure tank and steam at 100 ° C. or higher is supplied. This method requires a pressure vessel in order to heat the wood to 100 ° C. or higher, and has a drawback that the equipment cost is extremely high. In addition, since the method of heating wood with steam conducts heat from the surface of the wood and heats it, it takes a considerable time to heat the wood to the inside, and it is difficult to dry the wood efficiently in a short time . In particular, pillars and logs are
It takes a long time to heat the central part and cannot be dried in a short time. In addition, this method also has the disadvantage that the surface shrinks and breaks easily because the wood is dried from the surface.

[0003] As a device for heating wood from the inside, wood is heated by sandwiching it between electrodes connected to a high-frequency electrode.
Drying equipment has been put to practical use. This device heats the wood with the high frequency loss of the wood placed between the electrodes. This apparatus can dry thin wood such as a plate material relatively efficiently, but has a drawback that it cannot efficiently heat wood such as pillars that are thicker in terms of surface area or round wood such as raw wood. This is because pillars and the like cannot be sandwiched between wide electrodes, and if a log is sandwiched between planar electrodes, wood cannot efficiently absorb high frequencies. Further, this device has a drawback that the ideal electrode shape and size differ depending on the shape and size of the wood to be dried, and it is difficult to dry various woods with the same device. In addition, there is also a problem that high-frequency waves are radiated to the surroundings between the electrodes as radio waves.

[0004] An apparatus for drying wood by irradiating it with microwaves has excellent features not found in an apparatus sandwiched between electrodes. In particular, this drying device has a feature that the wood is heated from the inside because the wood is heated and dried by absorbing the microwaves into the wood. Wood heated from the inside shrinks from the inside, so that cracks on the surface can be reduced. Further, since the inside which is difficult to heat is efficiently heated, there is a feature that the time for heating and drying can be significantly reduced.

[0005] A drying apparatus using microwaves is described, for example, in Japanese Patent Application Laid-Open No. 60-178282. In the apparatus described in this publication, as shown in FIG. The conveyor 3 penetrates the waveguide 13. The wood 1 transferred by the conveyor 3 is heated and dried by being irradiated with microwaves when passing through the inside of the waveguide 13. The conveyor 3 is provided so as to penetrate the plurality of waveguides 13. Further, the plurality of waveguides 13 are provided inside the drying case 20. The conveyor 3 has both ends of the belt protruding outside the drying case 20, and is bent at the protruding portion.

[0006]

The wood drying apparatus shown in FIG. 1 continuously dries wood by microwaves. This type of device can dry thin wood such as boards. However, it is difficult to efficiently dry wood such as pillars and logs. Minimize external leakage of microwaves to cover long and thick wood,
This is because it is difficult to irradiate a strong microwave. In the wood drying apparatus of this structure, when the output of the microwave is increased, the microwave leaking to the outside is increased, and the environment becomes unfavorable for the worker. Microwaves have the property of leaking to the outside if there is a gap wider than the wavelength. The wavelength of microwaves used for drying wood is extremely short,
It has the property of leaking outside even from a narrow gap.

[0007] The present invention has been developed with the aim of further resolving this drawback. An important object of the present invention is to irradiate a long and thick timber with a strong microwave to efficiently operate it in a short time. An object of the present invention is to provide a wood drying device that can dry well.

Another important object of the present invention is to use a low-output magnetron mass-produced at low cost,
It is an object of the present invention to provide a wood drying device that can irradiate high-power microwaves to wood.

[0009] Still another important object of the present invention is that
An object of the present invention is to provide a wood drying apparatus which can minimize leakage of microwaves to the outside even though strong microwaves can be applied to the wood.

Still another important object of the present invention is to provide a wood drying apparatus which can adjust the number of case units to be connected and can manufacture an apparatus suitable for the length of wood to be dried at low cost. .

[0011]

The wood drying apparatus of the present invention has the following unique configuration. Wood drying equipment prevents microwaves from leaking out
The outer shield case 2 and the outer shield case 2
Arranged inside, microwaves are illuminated on the wood 1 to be carried in.
Radio wave case 21 to radiate, and carry wood 1 to radio wave case 21
To enter and discharge the wood 1 from the radio wave case 21
A conveyor 6 is provided. The outer shield case 2 is thin
Elongated hollow cylindrical shape extended in the transport direction of long timber 1
Made of metal shielding material to prevent microwave leakage
Have been. At the end of the outer shield case 2, wood 1
The entrance 8 for opening and exiting is opened. This doorway 8
The door 9 for preventing microwave leakage
It is provided in a state where Inside the outer shield case 2
The stored radio wave case 21 has a plurality of cables connected to each other.
Case unit 7 and the case unit 7
To form a radio wave case 21 in which wood 1 can be stored.
doing. Furthermore, each case unit 7 is
Microwave power supply 5 and microphone generated by microwave power supply 5
Antenna 4 that radiates black waves into case unit 7
It has. Of et al. In addition, Mai of each case unit 7
The microwave power supply 5 is a magnetron that generates microwaves
And a power supply circuit 12 for the magnetron 11.
ing. The microwave power provided in each case unit 7
The source 5 is connected to the antenna 4 provided in each case unit 7.
Each case unit from antenna 4 by supplying microwave
7 is irradiated with microwaves and stored in radio wave case 21
The wood 1 to be dried by microwave heating
Make up.

Further, in the wood drying apparatus according to the second aspect of the present invention, in order to heat and dry the entire wood more uniformly, the wood 1 is transported by the transfer conveyor 6 in a state where microwaves are irradiated from the antenna 4. Reciprocate back and forth.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate a wood drying apparatus for embodying the technical idea of the present invention, and the present invention does not specify a drying apparatus as follows.

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”. However, the members described in the claims are not limited to the members of the embodiments.

The wood drying apparatus shown in FIG. 2 has an outer shield case 2 for preventing microwaves from leaking to the outside,
A radio wave case 21 disposed inside the outer shield case 2 and irradiating the introduced wood 1 with microwaves;
Wood 1 is carried into radio wave case 21 and radio wave case 2
1 is provided with a transfer conveyer 6 for discharging the wood 1 from.

The outer shield case 2 is formed in an elongated hollow cylindrical shape extending in the transport direction of the elongated wood 1, and is made of a metal shield material such as an iron plate so as to prevent microwaves from leaking. Further, the outer shield case 2 has an entrance 8 at both ends, through which the wood 1 enters and exits.
The entrance 8 is closed in a state where it is electromagnetically shielded by an opening / closing door 9 that does not leak microwaves so as not to leak outside when microwaves are radiated.

The opening and closing door 9 does not leak microwaves, but is made of a porous iron plate or the like having many holes, which is sufficiently smaller than the wavelength of the microwaves so that the state of the wood 1 inside can be observed. It is a metal plate. A large number of small holes through which microwaves do not leak can also be provided on the side surfaces of the outer shield case and the radio wave case in order to check the dry state of the wood from outside.

The radio wave case 21 includes a plurality of case units 7
It consists of. The case unit 7 is opened at both ends,
The openings are connected to form a cylindrical radio wave case 21. The case unit 7 includes an antenna 4 for irradiating microwaves to the wood 1 placed therein, and a microwave power supply 5 for supplying microwaves to the antenna 4.

The radio wave case 21 has an elongated hollow cylindrical shape extended in the transport direction of the wood 1 so that the elongated wood 1 such as a pillar or a raw wood can be carried in.
It is made of metal shielding material such as iron. The radio wave case 21 shown in the drawing has an elongated cylindrical shape by connecting a plurality of case units 7 in series. The case unit 7 has a rectangular tubular shape with both ends opened, and the openings are connected to each other so that microwaves do not leak from the connecting portion, thereby forming a rectangular tubular radio wave case 21 as a whole. The total length of the radio wave case 21 can be easily changed by adjusting the number of connected case units 7. The total length of the pillars and logs to be dried is 3-8m. A device for drying short wood reduces the number of connected case units, and a device for drying long wood increases the number of connected case units.

Further, in the illustrated radio wave case 21, the openings 24 at both ends are closed in a state of being electromagnetically shielded by an opening / closing door 25 that does not leak microwaves. The opening / closing door 25 is fixed so as to be able to rotate inward as shown by a chain line in the figure, and the wood 1 carried into the radio wave case 21 and the wood 1 discharged from the radio wave case 21 pass through smoothly. I can do it. The radio wave case 21 having this structure includes the door 2
5, in addition to being able to effectively prevent microwaves from leaking from the openings 24 at both ends, the wood 1 can be carried in from one end and the wood 1 can be discharged from the other end. There are features that can be done well.

The antenna 4 and the microwave power supply 5 are built in the upper part of each case unit 7. The case unit 7 is provided with a power supply room 10 for housing the antenna 4 and the microwave power supply 5 at the upper part. The microwave power supply 5 housed in the power supply room 10 includes a magnetron 11 for generating microwaves, and a power supply circuit 12 for supplying the magnetron 11 with a high-voltage DC and an AC for heating a heater.
Consists of The magnetron 11 is connected to the antenna 4 via the waveguide 13 and supplies a microwave to the antenna 4. The antenna 4 is opened downward to the power supply room 10 so as to irradiate the microwave to the wood 1 in the radio wave case 21 from above.

The antennas 4 provided in each case unit 7 irradiate the wood 1 with microwaves at regular intervals. Antenna 4 provided in each case unit 7
Although the microwaves radiated from the medium interfere with each other, they are reflected and diffused in the transfer conveyor 6 and the radio wave case 21 to heat the long wood 1 uniformly. The interval between the adjacent antennas 4 provided in the radio wave case 21 is determined in consideration of the output of the microwave radiated from the antenna 4, the thickness of the wood 1, and the required drying time. When the antenna output is increased by reducing the distance between the antennas, thick wood can be heated and dried in a short time. For example, an antenna that outputs a microwave of 500 W can dry wood having a size of 10 cm square by several tens of minutes with an interval between adjacent antennas being 30 to 50 cm.

As shown in the figure, a case unit 7 in which an antenna 4 and a microwave power supply 5 are built in an upper power supply chamber 10.
In the drying device for drying long wood, the number of connected case units increases, and the total microwave output can be increased. For this reason, a long wood drying apparatus can increase the microwave output, and a short wood drying apparatus can reduce the microwave. Therefore, there is a feature that the case units having the same structure can be connected to each other to dry in an ideal state from short wood to long wood.

The transfer conveyor 6 shown in FIGS. 2 and 3 is a belt conveyor, and a plurality of rollers 14 are mounted on the bottom of each case unit 7 so as to be rotatable via metal bearings. The belt 22 is transported with the belt 22 placed thereon. Drive rollers 23 for driving a belt 22 of a belt conveyor are provided at both ends of the radio wave case 21. The roller 14 in the radio wave case 21 is mounted horizontally and parallel to the bottom of the case unit 7.

The drive roller 23 is connected to a reversible deceleration motor 17 which is a drive mechanism 15. The drive roller 23 projects the rotation shaft 16 to the outside of the outer shield case 2 for connection to the drive mechanism 15.
The deceleration motor 17 includes a chain 18 and a sprocket 19
Is connected to the rotation shaft 16 of the driving roller 23 via the. The drive mechanism 15 rotates the deceleration motor 17 to rotate the drive rollers 23 at both ends of the belt conveyor in the same direction. The deceleration motor 17 is rotated forward when the wood 1 is carried into the radio wave case 21 and when the wood 1 is discharged from the radio wave case 21. Forward rotation of deceleration motor 17
Rotates the drive roller 23 in the direction of loading or unloading the wood 1.

Furthermore, when the outer shield case 2 is closed and the wood 1 is irradiated with microwaves, the deceleration motor 17 rotates the drive roller 23 in the forward and reverse directions to reciprocate the wood 1. The stroke for reciprocating the wood 1 is, for example, １ ／ to 1 of the interval between the adjacent antennas 4.
Range. Further, the speed of reciprocating the wood 1 does not need to be so high. For example, the wood 1 is reciprocated at a speed in which one stroke of one reciprocation takes 5 seconds to 2 minutes.

Although the apparatus shown in the figure has a drive mechanism connected to a belt conveyor, the drying apparatus of the present invention does not necessarily need to have a drive mechanism connected to the belt conveyor. This is because a belt conveyor without a driving mechanism can push wood and carry it into the radio wave case, and can push out or pull out dried wood and discharge it from the radio wave case.

Further, in the drying apparatus shown in the figure, a belt conveyor is used as a transfer conveyor, but a roller conveyor or a chain conveyor can be used as the transfer conveyor.

In the above embodiment, a plurality of case units are connected in a line to form a cylindrical radio wave case. However, in the wood drying apparatus of the present invention, a plurality of case units can be connected in two rows as shown in FIG. In the drying device shown in this figure, two rows of case units 7 connected in series are further connected in parallel to form one radio wave case 21. The case units 7 connected in two rows have the lateral width of the hollow cylindrical portion removed by removing the wall of the boundary portion to be connected. In other words, the radio wave case 21 has a wide rectangular tube shape. Further, the transfer conveyor 6 disposed at the bottom of the radio wave case 21 is a belt conveyor, and the width of the belt 22 is made substantially equal to the width of the hollow portion of the radio wave case 21. The belt 22 is provided through a hollow portion of the radio wave case 21, and is driven by driving rollers 23 disposed at both ends of the radio wave case 21. Wood carried into the radio wave case 21 is heated by being uniformly irradiated with microwaves from the magnetron 11 disposed above each case unit 7.

As described above, in the drying device in which the case units are connected in two rows, the width of the hollow portion of the radio wave case 21 can be increased. Further, since the number of the case units 7 is doubled, the microwave output of the entire apparatus can be doubled. For this reason, in addition to being able to carry in and dry a wide flat plate material, there is also a feature that a large number of square materials and logs can be carried in and dried at once. Therefore, this drying device
From thin rods to wide flat plates, it can be conveniently used according to the shape of the plate, and has excellent features that allow it to be dried efficiently.

[0031]

The wood drying apparatus according to the present invention has a feature that long and thick wood can be efficiently dried in a short time by irradiating a strong microwave to the whole wood. This is because the drying apparatus of the present invention has a radio wave case for irradiating microwaves to wood inside the outer shield case for preventing microwaves from leaking to the outside. The drying device having this structure effectively prevents the microwave from leaking to the outside in both the radio wave case and the outer shield case. In other words, regardless of the structure of the radio wave case installed inside,
The outside shield case located on the outside can completely prevent microwave leakage. Therefore, when drying long and thick wood, it can be dried efficiently by irradiating strong microwaves in a short period of time, and microwaves leak to the outside despite irradiating the wood with strong microwaves. There is a feature that can be reduced. The device capable of preventing microwave leakage has a feature that an operator can use it safely.

Further, the wood drying apparatus of the present invention is characterized in that wood can be irradiated with high-power microwaves by using a small-output magnetron mass-produced at low cost. That is, the drying device of the present invention connects a plurality of case units to form a radio wave case capable of storing wood therein, and each case unit has a microwave power supply and a microwave power supply. This is because an antenna that radiates microwaves inside the case unit is provided. The drying device having this structure can increase the microwave output of the entire device even if a microwave power source having a small output is used as the microwave power source. This is because, when drying long wood, the total number of microwave units can be increased by increasing the number of connected case units. Therefore, there is a feature that high-power microwaves can be applied to wood using a low-power magnetron that is mass-produced at low cost. Furthermore, since a small-output magnetron mass-produced at low cost is used, the manufacturing cost can be reduced and maintenance parts and the like can be easily obtained. In addition, the drying device can reduce the output of microwaves irradiated from each microwave power source, and thus has a feature of reducing radio wave leakage.

Further, in the wood drying apparatus of the present invention, the radio wave case is formed by connecting the openings of a plurality of case units having both ends opened. Therefore, there is a feature that the number of the case units to be connected can be adjusted to easily and inexpensively manufacture an apparatus most suitable for the length of wood to be dried.

Further, the wood drying apparatus according to the second aspect is characterized in that wood can be uniformly irradiated with microwaves and dried. It is the transfer conveyor of this drying device,
This is because it has a drive mechanism that can reciprocate the wood back and forth. In this device, the wood in the radio wave case is reciprocated by the drive mechanism in a state where the microwave is radiated from the antenna, so that the microwave can be uniformly radiated on the surface of the wood. In addition, the reciprocating wood changes its contact state with the transfer conveyor, so that the bottom surface of the wood can be evenly irradiated with the microwave without unevenness. Therefore,
Since the wood drying apparatus of the present invention can uniformly irradiate microwaves, in addition to being able to irradiate strong microwaves to the wood, it is possible to realize a feature that can efficiently and quickly heat and dry the wood in a short time. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional drying apparatus using microwaves.

FIG. 2 is a vertical sectional view of a wood drying apparatus according to an embodiment of the present invention.

FIG. 3 is a plan view of a transfer conveyor of the wood drying apparatus shown in FIG. 2;

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Wood 2 ... Outer shield case 3 ... Conveyor 4 ... Antenna 5 ... Microwave power supply 6 ... Transfer conveyor 7 ... Case unit 8 ... Doorway 9 ... Opening / closing door 10 ... Power supply room 11 ... Magnetron 12 ... Power supply circuit 13 ... Waveguide DESCRIPTION OF SYMBOLS 14 ... Roller 15 ... Driving mechanism 16 ... Rotating shaft 17 ... Deceleration motor 18 ... Chain 19 ... Sprocket 20 ... Drying case 21 ... Electromagnetic case 22 ... Belt 23 ... Drive roller 24 ... Opening 25 ... Opening / closing door

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F26B 3/347 F26B 13/04 F26B 13/10

Claims (2)

(57) [Claims] 1. Preventing microwaves from leaking to the outside
Outer shield case (2) and this outer shield case (2)
Microwaves are placed inside the timber (1)
Radio wave case (21) and radio wave case (21)
(1) is carried in, and wood (1) is discharged from the radio wave case (21).
Transport conveyor (6), and the outer shield case (2)
Microwave does not leak due to elongated hollow cylinder
Made of metal shield material and
At the end of the cold case (2), the timber (1) enters and exits.
The entrance (8) is open, and the entrance (8) has a microphone
Electromagnetic shielding of the open / close door (9) to prevent wave leakage
Radio wave case (21) built into the outer shield case (2)
Consists of multiple case units (7) connected to each other
And the case unit (7)
It forms a radio wave case (21) that can store materials (1) , and each case unit (7)
Power supply (5) and microwave generated by microwave power supply (5)
Antenna (4) that radiates the light inside the case unit (7).
Eteori, furthermore, the microwave power in each case unit (7) (5)
Is a magnetron (11) that generates microwaves and this
A power supply circuit (12) for the magnetron (11), and a microwave power supply (5) provided in each case unit (7).
Is attached to the antenna (4) provided in each case unit (7).
Each case unit from the antenna (4) by supplying micro wave
The inside of (7) is irradiated with microwaves and stored in the radio wave case (21).
The wood (1) to be stored is heated and dried by microwave.
Wood drying equipment configured as follows. 2. A driving mechanism (1) for reciprocating wood (1) back and forth in a state where microwaves are emitted from an antenna (4).
The wood drying apparatus according to claim 1, wherein the transfer conveyor (6) includes the step (5).