JP3155241B2 - Dielectric heating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the evaporation of water in response to heating, such as the drying of wood, the production of laminated materials using an adhesive, and the thawing of frozen foods (frozen meat, frozen side dishes, other frozen foods, etc.). The present invention relates to a dielectric heating method and a dielectric heating method for a heating object in which the impedance of the heating object greatly changes due to a phase transition from ice to water.

[0002]

2. Description of the Related Art It is known that wood is deformed with the progress of natural drying. Therefore, if undried wood is processed and used as it is, there is a risk that dimensions will be distorted later and the workpiece will be distorted. Because of this, a drying treatment is generally performed prior to use. At the time of drying treatment of undried wood, artificial drying treatment which requires only several tens of hours to several days is adopted today in order to save time for natural drying.

[0003] In recent years, wood drying is performed by applying a high frequency while sandwiching a long piece of sawn timber between a pair of electrode plates in a drying furnace (housing) in a state of being laminated through a crosspiece for ensuring ventilation. Dielectric heating systems have been provided.

FIG. 9 shows a schematic configuration of such a high-frequency drying apparatus. In this figure, a power supply unit 101 receives electric power from a three-phase 200 V commercial AC power supply and converts it to a DC power supply of a desired level. A high-frequency oscillation circuit 102 has a high frequency of 13.56 MHz and a high frequency of 20 KW (KVA), for example. Is output. The generated high-frequency output is supplied to a space 105 between a pair of electrode plates via an automatic tuning circuit 103 and an inductance unit 104. The wood to be dried is loaded into the heating furnace 106 in a state where the wood to be dried is stacked between the two electrode plates 105 via a crosspiece. When a high frequency is applied between the electrode plates 106 in this state, the heating of the water inside the wood proceeds by the dielectric heating, the water inside the material is pressed out to the surface layer, and the water is controlled to the required temperature and humidity. Drying is promoted by steaming with hot air.

[0005] Wood has an initial moisture content of about 100% or more, though it depends on the type, and the moisture content is reduced to about 15% or less by a drying treatment according to a user's request. I try to lower it. If the object to be heated whose initial water content exceeds 100% is reduced to a water content of 15% or less, the impedance on the load side as viewed from the high-frequency oscillation circuit 102 changes greatly. The automatic tuning circuit 103 is composed of an LC element, and is provided for automatically correcting a matching shift (frequency shift) due to an impedance change. The control unit 103a detects the matching shift due to the impedance change and contacts the movable part. (Capacitance) of the variable capacitor 103c having no section
Is adjusted by the motor 103b (for example, the opposing area of the opposing electrode plates is changed in a separated state), and the matching feedback control is realized.

[0006]

However, as described above, it is not easy to sufficiently cover the matching range with only the capacitance in the drying of wood in which the impedance greatly changes as described above. FIG. 10 is a time chart of the drying process. As the drying of the wood having a high moisture content progresses and the moisture content decreases, the current gradually decreases as the impedance matching becomes gradually difficult to obtain, and the effective inside of the wood is reduced. It can be understood that it becomes difficult to supply a specific power (increase in reflected power), which causes a decrease in efficiency. On the other hand, with this, the voltage between the electrode plates has increased, and the danger of spark generation has increased.

In addition, since the dielectric drying apparatus requires a large power of several to several tens of kilowatts (KW), this power loss is accompanied by a prolonged drying time due to a decrease in drying efficiency. It is uneconomical because it requires an additional electricity fee, and it also leads to environmental problems associated with electricity production.

In view of this, it is conceivable to adopt a configuration in which the inductance section 104 can be made variable so that matching can be corrected. The reason that there is a limit to the correction using only the variable capacitor is that, furthermore, as a result of having a cross-bar structure in which a cross-bar is interposed for each layer in the laminated wood, a discontinuous space having a different dielectric constant in high frequency (electric field) (ie, It is considered that the presence of the discontinuous space further promotes the mismatch.

[0009] Therefore, from the time when the impedance gradually changes during the heat treatment and exceeds the correction range of the variable capacitor, a manual operation for adjusting the inductance of the inductance unit by the operator is required. For this purpose, a known power meter (SWR) or the like capable of detecting reflected power is connected to the load side of the high-frequency oscillation circuit 102, and by observing this meter, it is observed that the matching is deviated and the reflected power is increased. Then, each time (regardless of day or night), the inductance must be adjusted in a direction to reduce the reflected power, so that a complicated and severe work is forced and manual labor is required.

In addition, since a large amount of power of several kW to several tens of kW is used in drying wood, a large reflective power meter capable of measuring the reflected power for such large power is required. There is also a problem that the power meter is expensive.

[0011] The present invention has been made in view of the above,
For example, a dielectric heating method and an apparatus for performing dielectric heating on a heating target having a large impedance change, such as wood for drying, eliminate the need for manual and expensive wattmeters, and further reduce processing time and power consumption. It is intended to provide.

[0012]

According to the first aspect of the present invention,
A dielectric heating device that performs dielectric heating by applying an electromagnetic wave from an electromagnetic wave generator to an object to be heated having a large impedance change from an application unit via an automatic tuning circuit configured as a variable type of one of the LC elements. A variable circuit section in which an element of the same type as the other element of the LC element is interposed between the electromagnetic wave generation section and the application section so that the component can be changed, and is set for the object to be heated. A storage unit that stores the change in impedance of the object to be heated in the elapse of time in accordance with the heating conditions in accordance with time as variable amount data of the variable circuit unit, a timer for measuring the heating time, and When heating the object to be heated under the heating condition, the component of the variable circuit unit is varied according to the variable amount data from the storage unit that is read according to the heating time from the timer. Those having a driving unit.

According to a seventh aspect of the present invention, an electromagnetic wave from an electromagnetic wave generator is applied to a heating object having a large impedance change via an automatic tuning circuit in which one of the LC elements is variable. A dielectric heating method for applying dielectric heating by applying a voltage from a part, wherein a variable element in which the same type of element as the other element of the LC element is interposed between the electromagnetic wave generating part and the applying part so that its component can be changed. It has a circuit unit, a driving unit that changes the components of the variable circuit unit, a timer that measures the heating time, and a storage unit, and performs heating according to the heating conditions set for the object to be heated. When the impedance change of the object to be heated in the elapse of time is obtained in advance as the variable amount data of the variable circuit unit corresponding to the time and taken into the storage unit, and the object to be heated is heated under the set heating condition, Serial reading a variable amount data from said storage unit in response to the heating time from the timer guided to the drive unit, in which varying the ingredients of the variable circuit portion.

According to these configurations, first, dielectric heating is performed on a heating target under heating conditions set according to the target. This heat treatment may be performed experimentally or at the time of the first drying treatment for a certain kind of heating object. In this process, the change in impedance of the object to be heated in the elapse of time during heating is represented by an LC element of one of the variable circuit sections, one of which is capable of changing its component (a capacitance element or an inductance element). It is obtained in advance as variable amount data corresponding to time.
That is, for example, when performing a drying process according to the type of wood, the components of the variable circuit unit are sequentially adjusted to an optimal state so as to minimize the deflection of the meter (a numerical value in the digital type) while observing the reflection type wattmeter at that time. The adjustment is performed, and the adjustment amount is stored in the storage unit in association with the time data. Later, when the same kind of object to be heated is subjected to the heating process under the already set heating condition, the adjustment amount, that is, the variable amount data is read from the storage unit according to the heating time from the timer, and the driving unit And the components of the variable circuit section are varied in accordance with the variable amount data, whereby efficient heating processing is performed in a proper matching state during the heating processing. As an application field, it is suitable for application to drying of wood, production of a laminated material by bonding the laminated material with an adhesive, or thawing of frozen food for thawing and foodstuffs. In the production of dry wood and laminates, the impedance changes due to the evaporation of internal moisture and adhesive moisture, and in the thawing of foodstuffs, the dielectric constant (ie, impedance) of ice and water changes significantly due to the phase transition from ice to water. Can be supported.

According to a second or eighth aspect of the present invention, the one element is a capacitance element and the other element is an inductance element. While automatic tuning is performed by the capacitance element, varying the inductance maintains proper matching.

According to a third aspect of the present invention, the variable circuit section is disposed apart from each other, one of which is connected to the electromagnetic wave generation section side, and the other is connected to the object to be heated side; And a relay member made of a conductive material in contact with the conductive member, wherein the driving unit moves at least one contact portion of the relay member with the conductive member on the conductive member to change the inductance. It is characterized by. According to this configuration, in the variable circuit portion, the short-circuit position between the two conductive members changes with the movement of the relay member, that is, the length between the electromagnetic wave generating portion and the electrode member changes, thereby changing the inductance. Will be

According to a fourth aspect of the present invention, the two conductive members are plate members and are arranged in parallel with each other, and the relay member is interposed between the two conductive plates in a state of being elastically deformed in a U-shape, and The part is characterized in that the relay member is slid in forward and reverse directions parallel to the surface of the conductive plate to increase and decrease the inductance. According to this configuration, the alignment can be obtained by a simple operation of simply moving the relay member in parallel.

According to a fifth aspect of the present invention, in the electromagnetic wave generator, a high-frequency electric field is generated between two electrode plates, and an object to be heated is interposed between the two electrode plates. It is characterized by being. According to this configuration, when the object to be heated is interposed between, for example, a pair of electrode plates, dielectric heating is performed by a high-frequency electric field of, for example, about several hundred KHz to several hundred MHz.

According to a sixth aspect of the present invention, there is further provided a heating housing for accommodating an object to be heated, and means for generating a high-temperature and high-humidity atmosphere in the housing for heating. It is characterized by being wood that is interposed between electrode plates in a laminated state and subjected to a drying treatment. By performing dielectric heating in a high-temperature and high-humidity atmosphere, suitable wood drying becomes possible. The temperature and humidity are appropriately set according to the heating target. The temperature is preferably in the range of about 50 ° C. to 100 ° C., the humidity is preferably about 60% to 90%, and it is also preferable that the temperature is finely adjusted appropriately in accordance with the progress of drying.

[0020]

FIG. 1 is a partially cutaway perspective view showing an example of a wood drying apparatus to which a dielectric heating apparatus according to the present invention is applied. In the drawing, a high-frequency generator is omitted. Also,
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, in which a fan portion is omitted. FIG. 3 is a block diagram of the present apparatus.

As shown in these figures, the wood drying apparatus 1
Preferably comprises a structure comprising a transportable unit structure 2. As shown in FIG. 1, the unit structure 2 is formed by a rectangular parallelepiped box whose six surfaces are surrounded by walls. Metal frame members 21 are arranged at ridges and other suitable places of the unit structure 2, and the frame members 21 form a rectangular parallelepiped skeleton. A door frame 22 is provided on one side of the skeleton, and the door frame 22 forms an entrance of a lumber (wood) R to the unit structure 2. A door 23 having a heat insulating structure is attached to the door frame 22 so as to be freely opened and closed. The door 23 has a small hole 23a for ventilation. An outer wall plate 24 and an inner wall plate 25 made of a thin metal plate are attached to the skeleton so as to sandwich the frame member 21. A heat insulating material 26 is filled between the outer wall plate 24 and the inner wall plate 25. I have. In the present embodiment, a galvanized color steel plate is applied to the outer wall plate 24 and the inner wall plate 25, and 50 mm thick glass wool is used as the heat insulating material 26.

Inside the unit structure 2, a floor surface 2a,
A drying room 20 (drying housing) surrounded by the inner wall surface 2b and the ceiling surface 2c is formed, and a door 23 of the drying room 20 is formed.
The equipment arrangement chamber 20a is provided above the upper edge of the apparatus, and a drying space 20b for drying the lumber R is provided below the equipment arrangement chamber 20a. The external dimensions of the unit structure 2 are, for example, 1.8 m in width (the side on which the door 23 is provided), 4.5 m in depth, and 1. m in height.
The height is set to 8 m, and the height of the drying space 20b is set to 1 m.

A partition plate 27 hangs down from the ceiling surface 2c in the equipment placement room 20a, and the equipment placement room 20a is bisected in the longitudinal direction by the partition plate 27, and a branch room 200a is formed for each. In each of the compartments 200a, between the inner wall surfaces 2b, a shielding plate 28 having a ventilation port 28a is provided upright at the center.

The blower fan 3 is attached to the shield plate 28 so as to face the blower opening 28a. By driving the fan 3, steam, which will be described later, is blown out from the blowing port 28 a into the drying space 20 b, and after passing through the gap of the lumber R formed by the crosspiece in the drying space 20 b, the shielding plate 2
8 and circulates through the drying chamber 20. In the present embodiment, two fans 3 each having 0.75 KW are provided, and the two fans 3 can adjust the amount of air to be blown within a range of 60 to 180 m ³ / min.

The present apparatus is provided with a high frequency generator 4 for dielectric heating by high frequency. The configuration of the high-frequency generator 4 is shown in detail in FIG. Inside the unit structure 2, a pair of electrode plates 41 and 42 to which a high-frequency output from the high-frequency generator 4 is supplied via an output line.
Can be loaded, and a sawmill R is provided between the electrode plates 41 and 42.
Are sandwiched in a laminated state. The sawn timber R is pierced by a crosspiece Rs in a cross-girder shape for each stage to ensure ventilation. The lower electrode plate 42 has a roller (caster) 42a on the lower surface thereof (see FIG. 1) in consideration of the convenience of loading and unloading of the lumber R.
Etc. are provided as necessary or can be attached.

Also, at an appropriate place outside the unit structure 2,
An electric heating type boiler 5 is attached. The steam generated from the boiler 5 is introduced into a pressure pump 52 provided at the center of the upper surface of the unit structure 2 through a steam pipe 51, is pressurized by the pressure pump 52, and passes through a pair of steam branch pipes 53. The drying chamber 20 is supplied into each of the equipment placement chambers 20a, and the inside of the drying chamber 20 is heated to a high-temperature and high-humidity atmosphere (eg, a
(Approximately 100 ° C., humidity about 50 to 90%). The boiler 5 is provided with a safety valve (not shown). When the amount of steam generated by the boiler 5 is larger than the amount of steam supplied from the pressure pump 52 into the drying chamber 20, excess steam is discharged from the safety valve to the outside. It is to be released.
In the case of the present embodiment, the boiler 5 has a built-in heater having a capacity of 3.4 KW. By heating water with this heater, steam having a pressure of up to 3 kg / cm ² G is produced by 5.1 k.
It can be generated at a rate of g / hr. Tap water or well water is directly supplied to such a boiler 5 via a predetermined hose or the like.
A cartridge type water tank having a capacity of 5 to 10 liters may be provided.

An exhaust pipe (exhaust hole) 60 communicating with the inside of the drying chamber 20 is provided at one corner of the upper surface of the unit structure 2 so as to discharge atmospheric air in the drying chamber 20. Inside the exhaust pipe 60, there is provided a damper 62 which rotates around the horizontal axis 61 to adjust the opening degree of the exhaust pipe 60. An actuator 63 for changing the opening of the damper 62 by rotating the horizontal shaft 61 around the axis is provided on the upper surface of the unit structure 2. 62
The degree of opening is adjusted. An exhaust fan 6 is provided below the exhaust tube 60. By operating the exhaust fan 6, the atmospheric air in the drying chamber 20 can be forcibly exhausted. In this embodiment, the exhaust fan 6 has a motor capacity of 65.
W is provided, and exhaust is performed at a capacity of 18 m ³ / min.

A control device 7 is provided on the upper surface of the unit structure 2. The control device 7 controls the humidity in the drying space 20b to a predetermined value with time or a predetermined control value stored in advance. It is automatically controlled based on a program.

The lead wire 8 has an outlet 81 at the tip. By connecting the outlet 81 to a predetermined power supply provided on site, the energy required for operating the wood drying apparatus 1 can be provided. . In addition, power may be generated using an energy source such as gas or oil.

The humidity in the drying chamber 20 is automatically controlled by the control device 7 attached to the unit structure 2. In order to perform automatic control, a temperature sensor and a humidity sensor (not shown) are provided in the drying chamber 20, and the temperature and humidity detected by these sensors are always input to the control device 7. The control device 7 controls the fan 3 based on the control program.
A control signal is output to the boiler 5, the pressure pump 52, and the actuator 63.

Next, the high frequency generator will be described with reference to the block diagram of FIG. The high-frequency generator 4 includes a control unit 40 having a built-in computer. The control unit 40 includes keys necessary for inputting drying conditions (heating conditions) and the like.
For example, it is made possible to receive the input contents from the operation unit 71 of the control device 7 having an instruction key, a numeric keypad, or the like, or has an operation unit dedicated to the high frequency unit. The input is made via the operation unit 71 or the like.

As the drying conditions, at least the initial water content (120 to 80%, etc.) and the drying time (50 to 200 hours "hour", etc.) are employed, and the finish water content (20 to 15%).
Etc.) are important. The type of wood may differ slightly in moisture content depending on the type of wood, and there may be some differences in the internal structure and shape, which may lead to differences in the water passage diameter. It does not necessarily have to be adopted as a condition. The power does not need to be constant (for example, a rated value) during the processing period, and may be changed and set as time passes. Other factors include the tread area, length,
The number of layers (the above may be collectively treated as a load amount) and the number of layers, humidity (amount of steam supply), and temperature can be adopted in an apparatus for drying in a drying housing (heating furnace). In the case of acquiring different variable data depending on the difference in the initial moisture content due to the place of production or the like even among the same kind of wood, a more efficient drying process can be provided.

A serial number (may be a symbol) or the like is assigned to the contents set as described above, and a data storage unit 4 such as a writable ROM or RAM provided in the control unit 40 or attached thereto.
0a can be registered (stored). Also, C
An RT or LCD (liquid crystal) display unit may be provided so that the registered contents may be read out from the data storage unit 40a and displayed so as to be visible. This has the advantage that the registered contents can be confirmed when necessary. is there.

The power supply circuit 44 receives a supply from a commercial power supply of, for example, three-phase 200 V, converts this power into a required level of direct current, and outputs it. The high-frequency oscillation circuit 45 has an internal oscillator or the like, and converts a DC power supply from the power supply circuit 44 into a high frequency of a required frequency and outputs the converted power as, for example, rated power. The automatic tuning circuit 46 is composed of LC elements, and at least one of the LC elements is configured so that its components can be adjusted. The automatic tuning circuit 46 supplies power in a predetermined matching state by matching with a load (timber R). It is something to make. That is, when the internal moisture evaporates and goes out to the outside as the wood dries, the dielectric constant on the load side changes, that is, the impedance changes. Therefore, the change in the power (anode current level) at this time is detected and The feedback correction is performed so as to maintain the matching condition by adjusting the capacitance of the variable capacitor. In a mode in which the temperature sensor is provided inside the drying chamber 20,
It is preferable that the application of high frequency is controlled on / off based on the detected internal temperature so that overheating of the material can be effectively prevented.

The variable inductance circuit 47 is provided at least between the high-frequency oscillation circuit 45 and the electrode plate 41 (applying unit), and is adapted to maintain the matching even outside the correction range of the automatic tuning circuit 46. The configuration is such that the inductance is changed based on an operation signal from the control unit 40.

FIGS. 5A and 5B are configuration diagrams showing one embodiment of the variable inductance circuit portion, wherein FIG. 5A is a side view and FIG. 5B is a front view. The variable inductance circuit portion 47 is provided with a resin plate 472 having a required thickness, which is disposed in parallel at a predetermined distance in a housing 471 made of resin, and is fixedly disposed from above and below by resin screws.
In the present embodiment, the three opposing surfaces 3
A row of strip-shaped aluminum plates 473 is fixed at its upper and lower positions with screws or the like. In FIG. 5A, of the aluminum plate members 473 facing each other, three of the aluminum plate members 473 on the left side are shown.
The book is connected to the output side of the automatic tuning circuit 46 at the upper right place P1 (contact position), and the three aluminum plate members 473 on the right side are connected to the electrode plate 41 at the upper right place P2 (contact position).

Further, a relay piece 474 (relay member) made of a conductive aluminum material elastically deformed, for example, into a U-shape in cross section, is provided in sliding contact with both inner surfaces of the opposed aluminum plates 473. ing. The relay piece 474 has a width that makes sliding contact with the three aluminum plate members 473. Further, at least the relay piece 474 is provided at the lower end position of the relay piece 474 in the width direction.
A non-conductive supporting member 475 extending beyond the width of the fixing member 475 is fixed, and a female screw is screwed at both ends thereof.
Are formed.

On the other hand, on both sides in the width direction of the housing 471, as shown in FIG. 5 (b), a threaded rod 476 having a pair of male threads threaded is disposed so as to be rotatable vertically. The engagement portions 475 a at both ends of the support member 475 are screwed to the screw rod 476. Therefore, the screw rod 47
When the rotating member 6 rotates in the forward and reverse directions, the supporting member 475, that is, the relay piece 474, moves up and down in an interlocking manner. For example, when the relay piece 474 rises, the short-circuit length between the position P1 and the position P2 becomes shorter and the inductance decreases through the relay piece 474, and conversely, when the relay piece 474 falls, the relay piece 474 is moved. The length of the short circuit between the position P1 and the position P2 becomes longer to increase the inductance, thereby making it possible to vary the inductance. The upper end of the screw rod 476 has a rotation transmission mechanism 477 (shown by a broken line) mainly composed of a gear group and a motor as a drive source in which a motor shaft is connected to a rotation shaft at the most upstream position of the transmission by meshing or the like. 478 is provided in the housing 471. The amount of rotation of the motor 478 is set by an operation signal from the control unit 40.
The pair of screw rods 476 are rotated in the forward and reverse directions by rotating the joint 78 in the normal and reverse directions by a predetermined amount. As a result, the relay piece 474 is raised and lowered by a predetermined amount.

Next, the adjustment of the inductance will be described with reference to FIG. FIG. 6 is a time chart showing the relationship among the moisture content of wood, incident (input) power, reflected power, and the amount of inductance adjustment (movement) in the wood drying process.

In FIG. 6, the drying time (h) is plotted on the horizontal axis.
“Hour”), the power (KW) is set on the left vertical axis, and the movement amount (cm “L length”) of the relay piece 474 is set on the right vertical axis. In this embodiment, the type of wood to be dried is “cedar” and 1
Those having an initial moisture content slightly higher than 00% are employed, each of which has a small edge shape of 120 mm x 120 mm, a length of 170 cm, and six are arranged in one stage, and the number of lamination stages is eight,
Further, about 10 KW is set as the input power and 80 h is set as the drying time.

Referring to FIG. 6, a procedure for acquiring the movement amount data will be described. At this time, a reflection-type wattmeter is connected to the circuit to observe the fluctuation of the meter. The initial position of the inductance length (L length: variable amount data) is 0 cm.
The inductance correction is performed from a predetermined time position at the beginning of the drying start (about 16 hours after the start in FIG. 6), that is, from a point before the matching adjustment by the correction based on the reactance component is considered to exceed a suitable range. Is working.

First, wood to be dried is loaded between the electrode plates 41 and 42 of the wood drying apparatus 1, and a drying operation is started. With this start, the built-in timer 40b starts the aging operation.

In the initial stage of the application of the high frequency, the high frequency power is consumed to increase the internal temperature of the wood, and the water content does not decrease so much. Therefore, neither the incident power nor the reflected power changes much.
Note that the slightly higher reflected power seems to be peculiar to the initial transition period. When the water content starts to decrease after a certain period of time, the reflected power starts to increase accordingly, and the operation of adjusting the L length is started. The adjustment time of the L length may be a predetermined time interval, for example, 1 hour or 30 minutes, but may be set to a fine time interval such as 10 minutes in order to increase the matching accuracy. The interval of this adjustment time may be fixed,
When the fluctuation of the wattmeter is large, the setting can be made each time, and the matching accuracy can be further improved. On the contrary, the setting can be suspended during a period in which the fluctuation is small to reduce the number of data.
In any case, the time information of the timer 40b at the time of adjustment together with the adjustment data is stored in the data storage unit 40a shown in FIG.
It is taken in. The L length can be adjusted by observing the wobble of the wattmeter (while observing the numerical value in the case of digital display) from the operation unit 71 or a predetermined operation unit on the high frequency unit side.
This is possible by transmitting an operation signal in the forward and reverse directions to 8 and moving the relay piece 474 in the forward and reverse directions.

Thereafter, if the water content decreases with the passage of time and the L length is left unadjusted, the matching gradually shifts as shown in FIG. Although the voltage increases, that is, the reflected power increases and the input power decreases, the L length is set and adjusted each time at a position where the reflected power is minimized in the wattmeter. Then, after 80 (h), dried wood having a water content of about 15%, which is close to the intended purpose, was obtained. As shown in FIG. 6, the result of the L length that has been successively adjusted as shown in FIG.
It rises to the right (in a direction to decrease the inductance) according to time.

The operation amount specified by the operation unit 71 or another operation unit is sequentially taken into the data storage unit 40a as L length data. Alternatively, a record is stored in association with the adjustment time and the adjustment amount, and this record is later stored in the data storage unit 40a.
May be manually input with one pattern number attached.

FIG. 7 shows an example of a data map of L length data recorded in the data storage section 40a. FIG.
In, a sequential time and a moving amount are written in association with each pattern number indicating a drying pattern based on the set drying condition. In pattern number 1, the length L is a length from the initial position (0 cm), and t1 to t1.
Until ti, 0 cm, the data adjusted for the first time at t (i + 1) is 0.5 cm, and the final tn is 28.0 cm. In the pattern number 2, the L length corresponding to τ1 to τn is stored. ing. The time in each pattern number may be the same timing, but may be unique for each drying pattern. Note that the L length data may be defined by the length from the initial position. However, when the motor 478 is, for example, a pulse motor or the like, the length between the immediately preceding position and the next position is defined by, for example, the number of pulses. Is also good.

Thereafter, for example, when performing a drying operation at a later date, the operation is performed in the following procedure. FIG.
5 is a flowchart showing a procedure of a drying operation.

When the power is turned on, this flowchart starts. First, it is determined whether or not a predetermined key of the operation unit 71 has been operated (step S1). If a predetermined key is not operated and another key is turned on, the computer does not take any special role as a normal drying process without using the registered drying pattern. However, the control device 7 executes normal control such as on / off control of the operation of the boiler 5 using a temperature sensor, a humidity sensor, and the like (not shown).
When the data storage unit 40a is not used, the input contents may be simpler conditions (for example, power supply and drying time), or may be set without any conditions (in this case, the rated output set for the device is Supplied and the drying time is continued until the operator performs a power-off operation).

In addition, a key input for performing a drying process may be received while also acquiring data using a new heating pattern. Further, even when the drying process is performed under the same drying conditions as those in which the heating pattern is already registered, both may be selectable so that the drying can be performed by the normal drying process. In this way, the start key is turned on and normal drying is performed.

In step S1, if a predetermined key is pressed (operated), the operation unit 71 then instructs input of a corresponding pattern number by pressing a ten key (step S3). Alternatively, a ten-key may be pressed together with the predetermined key. The pattern number data is set in accordance with the instruction of the pattern number, that is, set to a readable state, or transferred to the processing RAM so as to be sequentially readable (step S5). Subsequently, it is determined whether the start key has been turned on (step S).
7) When turned on, the drying process is started by using the electric power or the like in the drying pattern of the present pattern number, and the timer 40b is turned on (step S9). Next, it is determined whether or not the timer 40b has reached the first adjustment time of the set pattern number.

Now, a description will be given assuming that the pattern number 1 has been designated in step S3. Time t1 from the start of drying
Has elapsed (YES in step S11), the L length 0c
m is read and output as an operation signal (step S13). Then, it is determined whether the drying is completed (step S15). If not, the process returns to step S11 to determine whether the next adjustment time has been reached, and the L length data is read out as described above. , And thereafter, step S1
The loop from step 1 to step S15 is repeated, and when the drying time is one of the drying conditions (input otherwise when the drying condition is not satisfied), when the drying time is reached, step S15 is performed.
It is determined that drying is completed at 15 (YES at step S15),
The power is turned off and the drying process ends. In the embodiment in which the moisture content is set as the condition for terminating the drying, a moisture content sensor may be provided, and the termination of the drying may be controlled based on the sensor output. As a moisture content sensor, there is a weighing scale or the like, and the moisture content can be obtained by measuring the amount of moisture that has escaped based on the change from the initial weight.

The present invention is also applicable to the following embodiments. (1) In the above embodiment, external heating using high-temperature steam and dielectric heating are used in combination. However, the present invention provides a wood drying apparatus of a type that performs drying processing in a degassed state using a vacuum drying furnace (drying housing). Is also applicable. In this case, if the degree of vacuum is set depending on the material, the set degree of vacuum may be set as the drying condition.

(2) The present invention is not limited to the drying treatment, but can be applied to the production of a veneer laminate. The veneer laminate is made by laminating a required number of veneers on a veneer having a required thickness with an adhesive interposed therebetween, and performing dielectric heating in a pressed state to integrate the veneer with the adhesive. The heating conditions in this case may include the thickness of the veneer, the number of layers, the type of adhesive (curing temperature and moisture content), and the like.

(3) The present invention is also applicable to a dielectric heating device for thawing frozen foods. For example, beef, pork, chicken, etc. as raw materials for hamburgers are -20 to -25 ° C.
It is thawed to about -3 to +3 [deg.] C. using a dielectric heating device and is lowered in the next manufacturing process to become a hamburger as a final product. In this case, in the frozen state, the water-containing water is frozen and becomes ice, which returns to water by thawing, but the thawing process proceeds because the dielectric constant of ice and the dielectric constant of water are significantly different. , The misalignment is remarkable, and the automatic correction of the inductance enables highly efficient decompression processing.

(4) The configuration of the variable inductance circuit section is not limited to the above embodiment, and at least one conductive plate 473 may be used. Further, the relay piece 474 is not limited to the movement at both ends and may be fixed at one end.
In short, any structure may be used as long as the inductance length can be changed as a result of the position of the relay piece being moved between the two conductive plates 473 while being connected to both. Furthermore, one conductive flat plate and a conductive slider that slides on one surface in the longitudinal direction are formed. One end of the conductive flat plate is connected to the automatic tuning circuit 46, and the conductive slider is connected to the electrode plate 41. It may have a connected configuration.

(5) The present invention is not limited to the high-frequency operation using the counter electrode. The high-frequency operation of the positive electrode and the negative electrode is alternately supplied to the grid electrodes arranged in parallel in one direction. (Wood or the like) may be integrally bonded with an interposed adhesive, and may be applied, or a microwave irradiation chamber may be irradiated with microwaves.

(6) In the present embodiment, the timbers are laminated with the crosspiece interposed therebetween. However, the present invention is not limited to this, and the present invention can also be applied to those laminated as they are. In the configuration with the crosspiece, the high-frequency electric field may be slightly concentrated on the crosspiece portion. However, when the matching is secured with high accuracy, the power loss is considerably reduced as compared with the case where the matching is not ensured. There is an advantage.

(7) Also, the electrode plates are not limited to those arranged on the upper and lower sides of the laminated material. A required number of electrode plates are interposed in the middle, and a predetermined time interval is set between adjacent electrode plates. The present invention is also applicable to a device that repeats an operation of applying a high frequency in order.

(8) The adjustment of the L length (inductance) can be realized by a sequence process without using computer control.

(9) In the present embodiment, the length L is proportional to the time direction, and the gradient varies depending on the drying conditions. However, it does not necessarily change linearly depending on the heating target. Of course, the invention is fully applicable to such.

(10) In the above embodiment, the adjustable element of the automatic tuning circuit 46 is used as a capacitor, and the element adjusted under heating conditions is adopted as an inductance element (variable circuit section). The variable circuit section need not necessarily be a different type of component element from the variable element of the automatic tuning circuit 46, and may be the same type of component element. In a mode in which a variable capacitor is used instead of the variable inductance circuit unit 47, the high-frequency oscillation circuit 45
And an electrode (applying unit) may be interposed in series or in parallel.

(11) In this embodiment, an aluminum plate 473 as a plate is used as the inductance circuit portion 47.
However, the present invention is not limited to the configuration of the inductance circuit, and the conductive pipe-shaped members are arranged in parallel at a required distance from each other, and the conductive pipe-shaped members are connected with the connecting rods in a state where they are electrically connected. It is also possible to adopt a structure in which the bridge member is movable in the longitudinal direction of the pipe so that the inductance can be changed and adjusted.

[0063]

According to the present invention, the dielectric heating process for a heating object having a large impedance change can be automatically corrected with the previously obtained variable amount data, so that the heating operation does not require manpower and is expensive. Eliminates the need for a wattmeter,
Furthermore, processing time can be reduced and power consumption can be reduced.

According to the second and eighth aspects of the present invention, it is possible to correct the misalignment by adjusting the inductance of the inductance element.

According to the third and fourth aspects of the present invention, the inductance can be changed by moving the relay member.

According to the fifth aspect of the present invention, the present invention can be applied to an apparatus using a high frequency, and a heat treatment can be performed by interposing an object to be heated between electrode plates.

According to the sixth aspect of the present invention, laminated wood can be efficiently dried in a high-temperature and high-humidity atmosphere.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a wood drying apparatus to which a dielectric heating device according to the present invention is applied.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a control block diagram of the wood drying apparatus.

FIG. 4 is a block diagram of a high-frequency generator.

5A and 5B are configuration diagrams showing one embodiment of a variable inductance circuit unit, where FIG. 5A is a side view and FIG. 5B is a front view.

FIG. 6 is a time chart showing the relationship between the moisture content of wood, incident (input) power, reflected power, and the amount of inductance adjustment (movement) in the wood drying process.

FIG. 7 is a diagram showing a data map of L length data.

FIG. 8 is a flowchart showing a procedure of a drying operation.

FIG. 9 is a diagram showing a schematic configuration of a conventional high-frequency drying device.

FIG. 10 is a time chart of a drying process by a conventional apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wood drying device 2 unit structure 20 drying room 3 fan 5 boiler 7 control device 71 operation unit 4 high frequency generator 40 control unit 40 a data storage unit 40 b timer 41, 42 electrode plate 44 power supply circuit 45 high frequency oscillation circuit 46 automatic tuning circuit 47 Variable inductance circuit portion (variable circuit portion) 473 Aluminum material plate 473 (conductive member, conductive plate) P1, P2 Upper right place (contact position) 474 Relay piece (Relay member) 475 Support member 475a Mesh 476 Screw rod 477 Rotation Transmission mechanism 478 Motor (drive) R Lumber (wood)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Yamamoto, Inventor 6-3-12 Kamishio, Tennoji-ku, Osaka Yamamoto Binita Co., Ltd. (72) Tsuneo Nagata 6-3-12 Kamishio, Tennoji-ku, Osaka Inside the Vinita Co., Ltd. (72) Inventor Junichi Kodama 6-3-12 Kamishio, Tennoji-ku, Osaka Yamamoto Within the Vinita Co., Ltd. (56) References JP-A-8-35778 (JP, A) JP-A-9- 133462 (JP, A) JP-A-59-121794 (JP, A) JP-A-3-58513 (JP, A) JP-A-8-288060 (JP, A) JP-A-11-148775 (JP, A) Japanese Utility Model Application No. 3-74497 (JP, U) Japanese Utility Model Application No. 1-2418 (JP, U) Japanese Utility Model Application No. 56-32418 (JP, U) Japanese Utility Model Application No. 55-71517 (JP, U) Japanese Utility Model Application No. 55-45203 (JP, U) (58) investigated the field (Int.Cl. ^7, DB ) F26B 3 / 347,23 / 08,9 / 06 H05B 6 / 50,6 / 68,6 / 64 H01F 21/06 H01F 29/06 - 29/12 H01F 39/00

Claims (8)

(57) [Claims] An electromagnetic wave from an electromagnetic wave generator is applied to an object to be heated having a large impedance change from an application unit through an automatic tuning circuit in which one of the LC elements is configured as a variable type to perform dielectric heating. A dielectric heating device to be applied, wherein a variable circuit section in which an element of the same type as the other element of the LC element is interposed between the electromagnetic wave generation section and the application section so that its component can be changed, and A storage unit that stores the change in impedance of the heating object in the elapse of time in the elapse of time according to the set heating condition in association with time as variable amount data of the variable circuit unit, and a timer that measures the heating time When heating the object to be heated under the set heating conditions, the configuration of the variable circuit unit is performed in accordance with variable amount data from the storage unit that is read according to the heating time from the timer. A dielectric heating device, comprising: a drive unit for changing the minute. 2. The dielectric heating apparatus according to claim 1, wherein said one element is a capacitance element, and said other element is an inductance element. 3. The variable circuit section is disposed apart from each other, one of which is connected to the electromagnetic wave generating section side, the other is connected to the heating object side, and the conductive section is in contact with both conductive members. And a relay member made of a material, wherein the driving unit moves at least a portion of the relay member in contact with the conductive member on the conductive member to change the inductance. 3. The dielectric heating device according to 2. 4. The relay member is a plate member and is arranged in parallel with each other. The relay member is interposed between the conductive plates in a state of being elastically deformed in a U-shape. 4. The dielectric heating apparatus according to claim 3, wherein the inductance is increased or decreased by sliding the plate in forward and reverse directions parallel to the surface of the conductive plate. 5. The electromagnetic wave generator according to claim 1, wherein a high-frequency electric field is generated between two electrode plates, and an object to be heated is interposed between the two electrode plates. The dielectric heating device according to any one of claims 1 to 4. 6. A heating housing for accommodating a heating object, and means for generating a high-temperature and high-humidity atmosphere in the heating housing, wherein the heating object is stacked between the two electrode plates. 6. The dielectric heating apparatus according to claim 5, wherein the wood is subjected to a drying treatment. 7. An inductive heating is performed by applying an electromagnetic wave from an electromagnetic wave generation unit to an object to be heated having a large impedance change from an application unit via an automatic tuning circuit in which one of the LC elements is variable. A dielectric heating method, wherein a variable circuit unit in which an element of the same type as the other element of the LC element is interposed between the electromagnetic wave generation unit and the application unit so as to change its component, It has a drive unit for changing the components, a timer for measuring the heating time, and a storage unit, and the impedance of the heating object in the time direction during heating according to the heating condition set for the heating object. The change is obtained in advance as the variable amount data of the variable circuit unit in correspondence with time and is stored in the storage unit, and when heating the object to be heated under the set heating condition, according to the heating time from the timer. A dielectric heating method, comprising reading variable amount data from the storage unit, guiding the variable amount data to the driving unit, and changing the components of the variable circuit unit. 8. The dielectric heating method according to claim 7, wherein a capacitance element is used as said one element, and an inductance element is used as said other element.