JPH0835778A - Wood temperature control method for wood drying equipment - Google Patents

Abstract

(57) [Summary] [Purpose] The temperature of wood is controlled by detecting the accurate wood temperature without degrading the commercial value of wood. [Structure] The wood 4 is supported by the electrode plate 8 in a sandwiched state, and a high frequency is applied to the electrode plate 8 to dry the wood 4 by dielectric heating. At this time, a thermometer 18 is embedded in the mouth 4a of the wood 4, and the wood 4 is attached to the mouth 4a.
The wood 4 by joining the auxiliary member 20 of the same quality as that of the predetermined shape
Was dried. Then, during the drying process, the temperature of the wood 4 is controlled by performing high frequency output control based on the temperature data detected by the thermometer 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood drying apparatus configured to dry wood by utilizing the heat generation effect of dielectric heating, and more particularly to a method for controlling the wood temperature during the drying process. .

[0002]

2. Description of the Related Art Conventionally, a drying chamber, a pair of electrode plates provided therein, a vacuum pump for setting the drying chamber to a predetermined vacuum state, and a high frequency generator for applying a high frequency to the electrode plate. There is known a wood drying apparatus having a.

According to this apparatus, a high frequency is applied to the electrode plates after the drying chamber is set to a predetermined vacuum state with the wood being held between the electrode plates, whereby the space between the electrode plates is increased. A high-frequency electric field is formed on the wood so that the wood is dielectrically heated.

[0004]

Since such an apparatus heats wood from the inside, a high frequency wave is generated according to the internal temperature of the wood, which is the highest temperature during the drying process, preferably the center temperature. It is preferable to perform output control and thereby maintain the temperature of the wood at a predetermined drying temperature according to the type of the wood in order to appropriately dry the wood.

However, in the case of the above-mentioned conventional apparatus, in reality, the dry state of the wood is detected based on the weight detection of the wood during the drying treatment or the detection of the amount of water evaporated from the wood, and as a reference, the drying chamber. The temperature of the wood is not accurately grasped because the wood drying process is performed by controlling the output of the high frequency while considering the ambient temperature of the wood.Therefore, the wood is overheated and the water content rapidly increases. Evaporates,
This may lead to cracks in the wood, so-called steam explosion, or conversely, insufficient drying of the wood due to insufficient heating of the wood, leading to poor drying.
This is extremely inconvenient in ensuring the stabilization of product quality.

Therefore, in view of the above-mentioned problem of keeping the temperature of the wood at a predetermined drying temperature according to the kind of the wood, the temperature of the wood is directly detected by burying a thermometer in the center of the wood. However, it is necessary to form a perforated portion for embedding a thermometer in the wood, and this method has a problem that the product value of the wood is likely to be impaired. Yes, it is difficult to implement in reality.

The present invention has been made to solve the above problems, and a wood drying apparatus capable of more accurately detecting the temperature of wood and controlling the temperature of the wood without impairing the commercial value of the wood. The purpose is to provide a temperature control method for wood in.

[0008]

The invention according to claim 1 is
In a wood drying device that supports wood between a pair of electrode plates in a sandwiched manner and applies a high frequency to the electrode plates to dry the wood by dielectric heating, a wood of substantially the same shape as the wood A dummy lumber with a temperature detection member embedded in a location is provided, the dummy lumber is mixed with the lumber to dry the lumber, and the temperature data detected by the temperature detection member is used during the drying process. Based on this, the output control of the high frequency is performed.

According to a second aspect of the present invention, there is provided a wood drying apparatus in which wood is sandwiched between a pair of electrode plates and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. , A temperature detecting member is provided at the mouth end portion of the wood, and in order to extend the mouth end surface, a detection assisting member having a predetermined shape is joined to the mouth end surface to dry the wood, and the drying treatment is performed. The output control of the high frequency is performed based on the temperature data detected by the temperature detecting member.

According to a third aspect of the present invention, there is provided a wood drying apparatus in which wood is sandwiched between a pair of electrode plates and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. Drying the wood in a state in which the first temperature detecting member is embedded at a predetermined depth from the wood mouth surface and the second temperature detecting member is disposed on the wood mouth surface or the other wood mouth surface. And the output control of the high frequency is performed based on the temperature data detected by the first and second temperature detecting members during the drying process.

According to a fourth aspect of the present invention, in the third aspect, the first temperature detecting member is disposed on the mouth side of the wood, and the detection assisting member having a predetermined shape is provided to extend the mouth side. The end surface of the detection auxiliary member that is different from the side on which the first temperature detecting member is arranged, or the end of the wood that is different from the side on which the first temperature detecting member is arranged, The second temperature detecting means is disposed on the surface of the wood mouth.

[0012]

According to the invention described in claim 1, it is possible to indirectly know the actual center temperature of the wood by detecting the center temperature of the dummy wood. Based on the detected temperature, the wood temperature of the wood is detected. By controlling the temperature, it becomes possible to keep the wood at an optimum temperature.

According to the second aspect of the present invention, it is possible to detect the temperature close to the actual inner temperature of the wood while detecting the temperature at the mouth of the wood. Based on this detected temperature By controlling the temperature of the wood with the wood, it becomes possible to keep the wood at the optimum temperature.

According to the third aspect of the present invention, the temperature control of the wood is performed based on the temperatures of the two points of the wood mouth surface portion and the outer surface of the wood.

According to the fourth aspect of the present invention, the first temperature detecting means is provided on the surface of the wood, and the detection assisting member is joined to the surface of the wood, whereby a predetermined distance is obtained from the surface of the wood. It is possible to detect the temperature in the same situation as when the temperature detecting member is embedded in the depth.

[0016]

EXAMPLES Examples of the present invention will be described.

FIG. 1 is a sectional view showing an example of a wood drying apparatus to which the wood temperature control method of the present invention is applied. As shown in this figure, the wood drying apparatus is mainly used for the drying chamber 1
And a vacuum pump 2 that sets the inside of the drying chamber 1 to a predetermined vacuum state, and a high frequency generator 3 that generates a high frequency when drying wood.

The drying chamber 1 is provided with a storage port for storing the wood 4 at one end side, and a sealing lid 5 is provided in the storage port. A truck 6 for mounting the wood 4 is provided inside the drying chamber 1, and the truck 6 is movably arranged on a rail 7 laid in the drying chamber 1.

Inside the drying chamber 1, the carriage 6
An electrode plate 8 to which the high frequency generated by the high frequency generator 3 is applied is disposed on the side of the wood mounting surface. The electrode plate 8 is composed of a pair of upper and lower cathode electrode plates 81a and 81b and an anode electrode plate 82 arranged between them. The lower cathode electrode plate 81b is attached to the carriage 6 and the upper side thereof. The cathode electrode plate 81a is attached to the lower surface of a pressing plate 13 which will be described later and is provided in the upper portion of the drying chamber 1. The cathode electrode plates 81a and 81b may be arranged at the above-mentioned positions as a matter of course, and may of course be separate from the carriage 6 and the pressing plate 13.

As shown in the figure, the anode electrode plate 82 is integrally laminated at an intermediate position of the wooden piece 4 placed on the carriage 6.

Further, the drying chamber 1 is provided with a strain prevention mechanism 9 for the wood 4 placed on the carriage 6, that is, a mechanism for preventing distortion such as warp associated with the drying of the wood 4. The strain prevention mechanism 9 includes a pressing plate 13 arranged in the drying chamber 1, lift shafts 10a and 10b integrally connected to the pressing plate 13, and lift shafts 10a and 1b.
It is composed of a drive mechanism section 12 for raising and lowering 0b with respect to the ceiling section of the drying chamber 1, and a motor 11 as a drive source of the drive mechanism section 12. When the motor 11 is operated in the strain prevention mechanism 9, the rotational driving force is transmitted to the drive mechanism portion 12 and, as a result, the lifting shafts 10a and 10a.
The b and the pressing plate 13 are integrally moved up and down.

Next, the control system of the wood dryer is shown in FIG.
A brief description will be given with reference to the block diagram of FIG.

The wood drying apparatus has a control section 15 having a computer as a component, and the vacuum pump 2, the high frequency generator 3, the strain prevention mechanism 9 of the drying chamber 1, etc. are all electrically connected to the control section 15. Connected to each other. In addition, the control unit 1
Reference numeral 5 denotes an operation unit 16 provided with a numeric keypad for inputting drying conditions and the like. For example, predetermined data such as the type and size of the wood 4 to be stored in the drying chamber 1 can be stored in the operation unit 1
By inputting via 6, the above-mentioned devices and the like are centrally controlled by the control unit 15.

The high frequency generator 3 includes a power supply circuit 3a,
A high-frequency generator circuit 3b and an automatic tuning circuit 3c are provided, and a power meter 17 for measuring the supplied power is additionally provided.

The power supply circuit 3a is supplied with power from, for example, a commercial AC power supply, converts this power into a direct current of a required level, and outputs it. The high frequency generating circuit 3b
Has an oscillator or the like inside, and converts the DC power from the power supply circuit 3a into a high frequency of a required frequency and outputs the high frequency.

The automatic tuning circuit 3c serves to match the load and supply power in a predetermined matching state. That is, when the water content inside the wood 4 evaporates and escapes to the outside as the wood 4 dries, the dielectric constant changes accordingly.
In accordance with this, the predetermined matching condition is always maintained, and the control unit 15 controls based on the measurement result of the power meter 17.

Further, a thermometer 18 for measuring the temperature of the wood 4 in the drying chamber 1 is connected to the control section 15, and the high frequency generator 3 is operated based on the detection result of the thermometer 18. It is controlled. That is, the high-frequency generator 3 is controlled to be turned on and off according to the temperature rise of the wood 4 due to the dielectric heating, so that the temperature of the wood 4 stored in the drying chamber 1 depends on its type, thickness and the like. It is designed to be kept at the optimum drying temperature.

Next, the first embodiment of the wood temperature control method according to the present invention will be described together with the wood drying treatment procedure in the wood drying apparatus.

First, the truck 6 is carried out from the storage opening of the drying chamber 1, and the wooden pieces 4 are stacked on the truck 6 and placed. In the embodiment, square wood is used as the wood 4, and as shown in FIG. 1, the wood 4 is placed on the carriage 6 in a state of sandwiching the anode electrode plate 82 and stacking it in two stages above and below the anode electrode plate 82. The wood pieces 4 are arranged in the same manner in the direction orthogonal to the paper surface of the figure.

Then, a thermometer 18 is embedded inside any one of the placed wooden pieces 4. Specifically, as shown in FIG. 3, the wood 4 has a predetermined depth (implementation) approximately at the center of the mouth 4a in the longitudinal direction of the wood 4 (left in FIG. 3) from the surface of the mouth 4a. The thermometer 18 is embedded by about 10 cm in the example. In particular, although the kind of the thermometer 18 is not limited, in the embodiment, a thermometer using an optical fiber is used. This thermometer has a structure in which a prism coated with a fluorescent substance is arranged at the tip of an optical fiber, irradiates the fluorescent substance with pulsed light through the optical fiber, and reflects the fluorescent substance from the reflected light. The temperature change is detected by detecting the change in the afterglow time. That is, since noise is easily affected by temperature detection in a place where the electric field is strong, accurate temperature can be detected by applying a thermometer using such an optical fiber. Other than this, a thermistor, a thermocouple, or the like can be applied, but in this case, it is necessary to eliminate noise through a low-pass filter or the like.

Next, for example, an auxiliary wood (detection auxiliary member) 20 of the same type as the wood 4 and having the same cross section as the wood 4 is joined to the ostium surface 4a of the wood 4. At this time, it is not always necessary to firmly bond the wood entrance surface 4a and the auxiliary lumber 20 and it is sufficient that the wood entrance surface 4a and the auxiliary lumber 20 are not separated from each other.

When the above work is completed, the dolly 6 is carried into the drying chamber 1, and the dolly 6 is fixed at a predetermined fixed position.
Then, after closing the lid 5 to seal the inside of the drying chamber 1, the motor 11 of the strain prevention mechanism 9 is operated to operate the pressing plate 13.
Is lowered, whereby the wood 4 in the drying chamber 1 is held by the pressing plate 13 and the carriage 6.

Then, after the vacuum pump 2 is operated to set the inside of the drying chamber 1 to a predetermined vacuum pressure, the high frequency generator 3 is activated to apply a high frequency of a predetermined frequency to the electrode plate 8. When a high frequency is applied to the electrode plate 8 in this manner, the cathode electrode plate 8
A high frequency electric field is formed between 1a and the anode electrode plate 82 and between the cathode electrode plate 81b and the anode electrode plate 82, and the high frequency electric field dielectrically heats the wood 4 to accelerate the drying of the wood 4.

At this time, when the temperature of the wood 4 rises due to the dielectric heating and the temperature detected by the thermometer 18 reaches a predetermined temperature preset according to the type of the wood 4 and the like,
The operation of the high frequency generator 3 is stopped, which causes the wood 4
Heating is suppressed. Then, when the temperature of the wooden piece 4 decreases with time, the high-frequency generator 3 is activated, and thereby the heating of the wooden piece 4 is promoted again. That is, the thermometer 18
By intermittently heating the wood 4 based on the temperature detected by the wood 4, the temperature of the wood 4 is kept at the optimum temperature for drying.

When the above-mentioned drying process is performed for a preset time, the driving of the vacuum pump 2 and the high frequency generator 3 is stopped, the motor 11 of the strain prevention mechanism 9 is reversely driven, and the pressing plate 13 is raised. After that, the cart 6 is carried out from the drying chamber 1 and the wood 4 is taken out, whereby the drying of the wood 4 is completed.

As described above, in the above-mentioned apparatus, the thermometer 18 is embedded in the mouth 4a of the wood 4 to detect the actual temperature of the wood 4, and the wood 4 is intermittently heated based on the detected temperature. However, since the temperature of the wood 4 is controlled by this, the wood 4 is more accurate than the conventional device.
The temperature can be controlled. In particular, not only by embedding the thermometer 18 in the vicinity of the wood mouth surface 4a of the wood 4 but also by joining the auxiliary wood 20 to the wood mouth surface 4a and performing the drying process, as described below. The temperature can be controlled extremely accurately.

That is, when the wood 4 is heated by dielectric heating, the heat is hidden in the center of the wood 4, so that the temperature distribution in the longitudinal direction of the central axis of the wood 4 is as shown by the solid line in FIG. It is the highest in the central part, and becomes asymptotically low in the vicinity of the mouth end surface 4a. Therefore, merely burying the thermometer 18 in the vicinity of the mouth 4a of the wood 4 is not sufficient because it detects a lower temperature than the central portion as shown in FIG.

However, as shown in the above embodiment, when the auxiliary lumber 20 is spliced to the wood entrance surface 4a, heat release in the vicinity of the wood entrance surface is suppressed, so that the wood entrance surface as shown by the chain line in FIG. The temperature gradient in the vicinity becomes gentle. As a result, the temperature difference Pb between the temperature detected by the thermometer 18 and the central portion temperature becomes smaller than the same temperature difference Pa when the auxiliary lumber 20 is not spliced, which makes it extremely close to the central portion temperature of the lumber 4. The detected temperature can be detected. For example, the temperature of the center of the wood 4, the temperature detected by the thermometer 18, and the surface 4 of the wood
It can be seen from FIG. 5, which is a graph showing the change over time of the surface temperature of a, that the temperature detected by the thermometer 18 is closer to the central temperature of the wood 4 than the wood mouth surface 4a.

Moreover, by joining the auxiliary lumber 20 as described above, the thermometer 18 is less susceptible to the influence of disturbance, and therefore the reliability of the detected temperature is improved.

That is, by joining the auxiliary lumber 20 in this manner, the temperature can be detected in the same condition as when the thermometer 18 is embedded at a deeper position from the wood mouth surface 4a, that is, at a position closer to the center. You can do it.

Therefore, according to the method for controlling the temperature of the wood 4 of the above-described embodiment, the temperature of the wood 4 is controlled based on the temperature which is closer to the central temperature of the wood 4, so that the temperature of the wood 4 during the drying process is controlled. Can be properly maintained at the optimum temperature for drying, and as a result, it is possible to properly use wood 4 without causing problems such as steam explosion due to overheating and non-drying due to poor heating.
Can be dried.

In the case of the above embodiment, since it is necessary to embed the thermometer 18 in the mouth 4a of the wood 4, it is feared that the commercial value of the wood 4 will be impaired. For the reason, there is a situation in which the wood mouth surface portion is cut in many cases, and therefore, there is no fear that the commercial value of the wood 4 is significantly impaired. Therefore, by embedding the thermometer 18 at the maximum allowable depth according to the type and length of the wood and detecting the temperature, the more accurate central temperature of the wood 4 can be obtained. It is possible to detect without damaging.

Although the method of controlling the high frequency generator 3 is not described in detail in the above embodiment, for example,
The on / off control of the high frequency generator 3 may be performed according to the actual detected temperature value, or the correlation between the central temperature of the wood 4 and the detected temperature of the thermometer 18 may be experimentally obtained in advance. Alternatively, this may be stored in the control unit 15 as a table, and ON / OFF control of the high frequency generator 3 may be performed according to the center temperature on the table obtained from the actual detected temperature of the thermometer 18. Furthermore, in addition to such on / off control, the high output level and the low output level (for example, the output 70
% And 30%).

Further, in the above embodiment, the thermometer 18 is embedded at a location approximately 10 cm deep in the wood 4 from the surface of the wood entrance surface 4a. The specific arrangement of the thermometer 18 may be appropriately set according to various conditions such as the type, length and thickness of the wood to be dried so that the wood is appropriately dried.

Next, a second embodiment of the wood temperature control method according to the present invention will be described.

In this embodiment, as shown in FIG. 6, the wood surface 4a of any one of the woods 4 mounted on the dolly 6 is mounted.
A thermometer 21a is embedded in the vicinity of the auxiliary wood 22, and the auxiliary wood 22 is joined to the wood mouth surface 4a as in the first embodiment, and the surface of the auxiliary wood 22, specifically, the auxiliary wood 22 is joined.
A thermometer 21b is attached to the end face 22a on the outer side (right side in FIG. 6) of the wood 4 and the wood 4 is dried in this state.

During the drying process, the inside temperature of the wood 4 near the mouth of the wood 4 is determined from the inside temperature of the wood 4 detected by the thermometer 21a and the outside surface temperature of the auxiliary wood 22 detected by the thermometer 21b. The temperature gradient of the wood 4 is calculated, and the temperature of the wood 4 is controlled by the central temperature of the wood 4 determined by the calculation result.

That is, in this embodiment, the correlation between the temperature gradient in the vicinity of the mouth of the wood 4 obtained from the detection results of the thermometers 21a and 21b and the actual center temperature of the wood 4 is obtained in advance, This is stored in the control unit 15 as a table, and at the time of drying, ON / OFF control of the high frequency generator 3 is performed based on the central temperature of the wood 4 determined from the table according to the temperature gradient obtained from the actual detected temperature. I'm trying to do.

According to the wood temperature control method of the second embodiment, since the central temperature of the wood 4 is obtained based on the temperatures at two points inside and outside the wood 4, the central temperature of the wood 4 is calculated. The temperature of the wood 4 can be controlled more accurately.

In the second embodiment described above, the auxiliary lumber 22 is spliced to the wood surface 4a of the lumber 4 and the thermometer 21b is attached to the outer surface of the auxiliary lumber 22, but the auxiliary lumber is not always necessary. 22 need not be spliced, thermometer 21
b may be directly attached to the wood surface 4a. However, from the viewpoint of preventing the influence of disturbance and increasing the reliability of the detected value by the thermometer 21a, it is preferable to join the auxiliary wood 22.

The thermometer 21b may be attached to the other surface of the wood 4, that is, the surface of the wood 4 different from the side where the auxiliary wood 22 is joined (reference numeral 23 in FIG. 6). Attach it at the indicated location). That is, since the temperature gradient of the timber 4 to which the auxiliary lumber 22 is attached is substantially equal at both ends thereof as shown in FIG. 4, instead of the end surface temperature of the auxiliary lumber 22, the other cusp surface temperature of the timber 4 is changed. Even if it detects, the required surface temperature can be detected.
In particular, when adopting such an arrangement of the thermometer 21b,
Since the thermometer 21b detects the surface temperature of the wood 4 itself to be dried, it is advantageous in that the reliability of the detected value becomes high.

Next, a third embodiment of the temperature control method for wood according to the present invention will be described.

In this embodiment, as shown in FIG. 7, the wood is the same as the wood 4 to be dried and has the same shape, that is, the center of the wood, that is, the center of the cross section of the wood, and its longitudinal direction. A dummy wood 25, in which a thermometer 24 is embedded, is provided in the middle part, and wood 4 to be dried
At the same time, the wood 4 is dried while being placed on the dolly 6. Then, during the drying process, the wood 4 is intermittently heated based on the temperature detected by the thermometer 24 so that the temperature of the wood 4 is maintained at a predetermined temperature.

According to the wood temperature control method of the third embodiment, since the dummy wood 25 has the same quality and the same shape as the wood 4 as described above, the central temperature of the dummy wood 25 is detected by the thermometer 24. Thus, the actual center temperature of the wood 4 can be indirectly known. Therefore, the temperature of the wood 4 during the drying process can be maintained at the optimum temperature with the same reliability as in the case where the temperature of the central portion of the wood 4 is directly detected and the temperature is controlled.

In the third embodiment, the dummy wood 25 is formed by embedding the thermometer 24 in the center of the same wood as the wood 4, that is, in the center of the cross section of the wood, and in the longitudinal middle thereof. However, it is not always necessary to embed the thermometer 24 in the center of the timber, and the temperature of the timber 4 required for temperature control should be set to the highest value according to various conditions such as the type, length and thickness of the timber to be dried. It may be set as appropriate so that it can be suitably detected.

Further, for example, a thermometer 24 is provided inside the wood which is of the same quality and the same cross-sectional shape as the wood 4 and which is shorter than the wood 4.
A dummy lumber 25 having a structure in which is embedded is provided, and the timber 4 is dried in a state where it is spliced to the opening 4a of the timber 4 in the same manner as the auxiliary lumbers 20 and 22 used in the first and second embodiments. During the drying process, the wood 4 may be intermittently heated based on the detection result of the thermometer 24 to control the temperature of the wood 4.

By the way, in the above-described embodiment of the present invention, in the above-mentioned first and second embodiments, the auxiliary lumber 20, 2 is used.
2 is composed of the same kind of wood as the wood 4 to be dried, but even if it is not the same kind of wood as the wood 4, the correlation of the temperature change between the wood 4 and the auxiliary woods 20 and 22 due to the difference in properties in advance. If you try to save
It is also possible to apply a different kind of wood from the wood 4 when forming the 22. Similarly, the dummy wood 25 of the third embodiment is different from the wood 4 as the dummy wood 25 if the correlation of the temperature change between the wood 4 and the dummy wood 25 due to the difference in properties is taken in advance. It is possible to apply different types of wood. Further, the auxiliary members 20 and 22 and the dummy lumber 25 do not necessarily have to be a water-containing material, and similar to the above, the correlation of the temperature change between the timber 4 and the auxiliary lumbers 20 and 22 and the dummy lumber 25 due to the difference in properties is previously taken. If it is kept, even dried wood can be used.

Further, as the auxiliary members 20 and 22 and the dummy wood 25, besides the wood itself, it is also possible to apply a wood-based material, that is, a material obtained by solidifying sawdust or the like with an adhesive, a resin material or the like. That is, if the material can be heated by electric field by high frequency, the auxiliary member 20,
22 and dummy wood 25 can be sufficiently applied.

[0059]

Industrial Applicability As described above, according to the present invention, wood is sandwiched between the electrode plates, and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. In the apparatus, a dummy lumber in which a temperature detecting member is embedded is provided at a predetermined position of the lumber having substantially the same shape as the lumber, and the dummy lumber is mixed with the lumber to dry the lumber, and the drying treatment is performed. In addition, since the output control of the high frequency is performed based on the temperature data detected by the temperature detection member, the center temperature of the wood necessary for temperature management is preferably detected without impairing the commercial value of the wood. As a result, the temperature of the wood can be controlled, and as a result, the wood can be appropriately dried without causing problems such as steam explosion due to overheating and non-drying due to poor heating.

Further, the present invention provides a wood drying apparatus in which wood is sandwiched between electrode plates, and high frequency is applied to the electrode plates to dry the wood by dielectric heating. A temperature detecting member is provided at the mouth end portion, and in order to extend the mouth end surface, a detection assisting member having a predetermined shape is joined to the mouth end surface to dry the wood, and during the drying process, Since the output control of the high frequency is performed based on the temperature data detected by the temperature detecting member, the temperature of the wood can be controlled based on the temperature extremely close to the temperature of the central portion of the wood, and The wood temperature can be kept better at the optimum temperature for drying.

Furthermore, the present invention provides a wood drying apparatus in which wood is sandwiched between electrode plates and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. The first temperature detecting member is embedded at a predetermined depth from the wood mouth surface, and the wood is dried while the second temperature detecting member is arranged on the surface of this wood mouth surface or the other wood mouth surface, During the drying process, the first and second
Since the output control of the above high frequency is performed based on the temperature data detected by the temperature detection member, it is possible to detect the center temperature of the wood more accurately, and the wood temperature during drying is optimal for drying. Can be better maintained at various temperatures. In the present invention, the first temperature detecting member is arranged on the ostium of the wood, and the detection assisting member is joined to the ostium of the wood, and the first temperature detecting member is disposed on the detection assisting member. The same effect can be obtained by disposing the second temperature detecting means on the end face on the side different from the side or on the mouth end side of the wood different from the side on which the first temperature detecting member is disposed. It is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a wood drying apparatus to which a wood temperature control method of the present invention is applied.

FIG. 2 is a block diagram showing a control system of the wood drying apparatus.

FIG. 3 is a diagram illustrating a first embodiment of the temperature control method for wood according to the present invention.

FIG. 4 is a diagram showing an example of temperature characteristics of wood during drying.

FIG. 5 is a graph showing an example of changes over time in the center temperature of wood, the wood entrance surface temperature, and the temperature detected by the thermometer in the first embodiment.

FIG. 6 is a diagram illustrating a second embodiment of the temperature control method for wood according to the present invention.

FIG. 7 is a diagram illustrating a third embodiment of the temperature control method for wood according to the present invention.

[Explanation of symbols]

 1 Drying Room 2 Vacuum Pump 3 High Frequency Generator 3a Power Circuit 3b High Frequency Generator 3c Automatic Tuning Circuit 4 Wood 5 Lid 6 Bogie 7 Rail 8 Electrode Plate 81a, 81b Cathode Electrode Plate 82 Anode Electrode Plate 9 Strain Prevention Mechanism 10a, 10b Lifting shaft 11 Motor 12 Drive mechanism part 13 Pressing plate 15 Control part 16 Operating part 17 Electric power meter 18 Thermometer 20 Auxiliary wood

Claims (4)

[Claims] 1. A wood drying apparatus in which wood is sandwiched between a pair of electrode plates and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. A dummy wood formed by embedding a temperature detection member in a predetermined position of a shaped wood is mixed with the wood to dry the wood, and the temperature detection member detects the temperature during the drying process. A method for controlling the temperature of wood in a wood drying apparatus, characterized in that the high-frequency output control is performed on the basis of the temperature data. 2. A wood drying apparatus, wherein wood is sandwiched between a pair of electrode plates, and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. A temperature detecting member is disposed in a portion, and a detection assisting member having a predetermined shape is joined to the above-mentioned mouth side to dry the above-mentioned wood in order to extend the above-mentioned mouth side. A method for controlling the temperature of wood in a wood drying apparatus, wherein the output control of the high frequency is performed based on temperature data detected by a member. 3. A wood drying apparatus in which wood is sandwiched between a pair of electrode plates and a high frequency is applied to the electrode plates to dry the wood by dielectric heating. A first temperature detecting member is embedded at a predetermined depth from the above, and the above wood is dried while the second temperature detecting member is provided on the surface of the wood mouth surface or the other wood mouth surface. A method for controlling the temperature of wood in a wood drying apparatus, wherein output control of the high frequency is performed based on temperature data detected by the first and second temperature detection members during processing. 4. The first temperature detecting member is disposed on the wood mouth surface, and a detection assisting member having a predetermined shape is joined to the wood mouth surface to extend the wood mouth surface, and the detection assisting member is joined. The second temperature detecting means is provided on an end face of the member on a side different from the side on which the first temperature detecting member is arranged or on a wood mouth face of the wood on a side different from the side on which the first temperature detecting member is arranged. The wood temperature control method in the wood drying apparatus according to claim 3, wherein the wood temperature control method is provided.