KR101816759B1 - A Control Method of Timber Drying Process using Microwave - Google Patents

Abstract

The present invention relates to a method for producing wood comprising: measuring an initial moisture content of wood; Irradiating the first microwave according to the initial moisture content to dry the wood first; Measuring the moisture content during drying of the first dried wood; And a second drying step of drying the wood by irradiating a second microwave according to a moisture content of the drying water. The present invention relates to a method of controlling a wood drying process using a microwave, The moisture content of the dried wood can be measured and moisture content of the dried wood can be measured. Therefore, excessive drying or overheating of the wood can be prevented by applying suitable microwave drying conditions according to the dried state of the wood.

Description

[0001] The present invention relates to a method of controlling a timber drying process using a microwave,

The present invention relates to a method of controlling a wood drying process using a microwave, and more particularly, to a method of controlling a wood drying process using a microwave that can apply appropriate microwave drying conditions according to the drying state of the wood.

Typically, the wood has a moisture content of about 80% by dry weight. If wood is used to make wood products such as furniture, the wood must be completely dried.

Natural drying methods include natural drying methods and natural drying methods in which timber is piled up and left in the air for several years to dry the wood. The forced drying method uses a drying furnace to dry the wood in a few weeks Is dried.

This method involves heating the medium of air and drying the heated air by a convection conduction method that transfers heat from the surface of the dried object again, which is accompanied by waste of energy due to surface heating and outflow of hot air.

Further, when the wood is dried by the hot air drying apparatus, the surface of the wood is cracked due to the characteristics of the wood, or the difference in the drying state between the outside and inside of the wood occurs due to heat transfer.

Furthermore, as the thickness or diameter of the wood to be dried increases, the drying becomes more difficult and the drying yield is lowered due to the occurrence of dry defects during drying. Immature materials containing moisture are inherently poor in mechanical properties and are easily broken by dry stress generated during drying. In order to completely dry the interior of wood, if it is dried by hot air for a long time, There is a problem that when the hot wind is blown at a low temperature that the outer side of the wood is not damaged, the drying takes a lot of time and the processing ability is significantly deteriorated.

In addition, since it takes a lot of energy to dry and the control of the heating temperature is not easy, there are many difficulties in automating the drying process.

In order to solve the above problems, a drying method using a microwave has been developed.

The microwave is radiated by the magnetron, and the microwave is injected from the center of the wood, and the moisture and radiant heat evaporate water molecules in the wood by the principle of dielectric heating.

Wood drying methods using microwaves can be divided into continuous and intermittent.

In the continuous type, since the wood is moved at a constant speed, the magnetron, which is a microwave generating device, is continuously operated, and the microwave can be dispersed evenly into the wood.

However, if a large amount of moisture, such as timber, must be removed over a long period of time, it is impossible to design it continuously. That is, the length of the conveying device must be very long and the conveying speed should be minimized, but in reality, such a design is not applicable. Therefore, it is necessary to design the intermittent system.

However, if the microwave drying equipment is designed in the intermittent mode, there is a high possibility that the microwave is concentrated during the drying process. Particularly, when a magnetron with a high output power is used alone, microwave concentration phenomenon becomes very strong, causing deformation or destruction of the wood.

In other words, microwave drying induces its own dielectric heating, unlike hot-air drying, so that the drying speed is quick and the drying imbalance inside and outside the wood can be greatly reduced. However, Failure to do so may cause a runaway phenomenon, such as overheating of a specific area, which can lead to excessive drying or fire due to overheating.

Therefore, in the process of drying the wood, it is necessary to apply appropriate microwave drying conditions according to the dried state of the wood to prevent excessive drying or overheating as described above.

Korean Patent Publication No. 10-2010-0013726

The present invention provides a control method of a wood drying process using a microwave capable of preventing excessive drying or overheating of a wood by applying appropriate microwave drying conditions according to the drying state of the wood during the process of drying the wood The purpose is to provide.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a semiconductor device, comprising: measuring an initial moisture content of a wood; Irradiating the first microwave according to the initial moisture content to dry the wood first; Measuring the moisture content during drying of the first dried wood; And a second drying step of drying the wood by irradiating a second microwave according to the water content during drying.

In addition, the present invention provides a control method of a wood drying process using a microwave, wherein the initial moisture content is measured through the following equation (1).

... 수학식 (1)

... Equation (1)

(Where Mi is the initial moisture content (% db), Wo is the total dry weight (kg) and Wi is the initial weight of the wood (kg)).

Also, the present invention provides a control method of a wood drying process using a microwave, wherein the total dry weight (kg) of Wo is measured by the following equation (2).

... 수학식 (2)

&Quot; (2) "

(Where Db is the basic density (kg / m 3) of the wood to be dried and Vi is the volume of the dry mass (m 3)).

In addition, the present invention provides a method of controlling a wood drying process using a microwave, wherein the water content during drying is measured by the following equation (3).

... 수학식 (3)

... (3)

(Where Mn is the moisture content during drying (% db), Wo is the total dry weight (kg), Wi is the initial weight of the wood (kg) and Wd is the weight of the condensate)

According to another aspect of the present invention, there is provided a wood drying apparatus using a microwave comprising a main body for drying wood and a control unit for controlling the main body, the main body including: a housing having a space for receiving the wood; A plurality of magnetrons for drying the wood contained in the housing; A power supply unit for supplying power to the magnetron; A plurality of temperature sensors for sensing the temperature of the wood being changed during the process of drying the wood; And a condenser for condensing water vapor generated during the process of drying the wood.

The condensing unit may further include a water vapor collecting unit for collecting the water vapor; A condenser for condensing the water vapor collected in the water vapor collecting unit; And a condensate weighing device for measuring the weight of the condensed water condensed in the condenser.

According to the present invention as described above, the moisture content of the dried wood can be measured by calculating the content of water vapor generated during the process of drying the wood through the condenser, By applying the conditions, excessive drying or overheating of the wood can be prevented.

Further, in determining the drying conditions for irradiating the microwaves, by considering the permeability index of the wood to be dried, more accurate drying conditions of the wood can be determined according to the characteristics of the wood.

1 is a schematic view showing a wood drying apparatus using microwaves according to the present invention.
FIG. 2 is a schematic flow chart for explaining a method of controlling a wood drying process using microwaves according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. &Quot; and / or "include each and every combination of one or more of the mentioned items. ≪ RTI ID = 0.0 >

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" And can be used to easily describe a correlation between an element and other elements. Spatially relative terms should be understood in terms of the directions shown in the drawings, including the different directions of components at the time of use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view showing a wood drying apparatus using microwaves according to the present invention.

Referring to FIG. 1, a microwave-based wood drying apparatus 100 according to the present invention includes a main body 110 for drying wood and a control unit 120 for controlling the main body.

First, the main body 110 includes a housing 2 having a space for accommodating the wood 1, and a plurality of magnetrons 4 for drying the wood contained in the housing. And a power supply unit (3) for supplying power to the magnetron (4).

At this time, the housing 2 may be configured to be hermetically sealed so that water vapor generated during the process of drying wood does not escape to the outside.

The power supply unit 3 supplies power to the magnetron 4 and the magnetron 4 emits a microwave to dry the wood 1. [

1, the main body 110 includes a plurality of temperature sensors 5 for sensing the temperature of the wood during the process of drying the wood, and a plurality of temperature sensors 5 for condensing water vapor generated during the process of drying the wood, And a condensing portion 6 for condensing.

The temperature sensor 5 is arranged at a predetermined interval in the wood 1 so as to determine whether or not an overheating phenomenon occurs at a specific position of the wood by detecting the temperature of the wood during the process of drying the wood . This will be described later.

The condensing section 6 is for measuring the moisture content of the dried wood by calculating the content of water vapor generated during the process of drying the wood, that is, through the content of water vapor condensed in the condensing section, The water content of the wood undergoing drying can be measured.

In general, it is impossible to install a sensor for measuring the water content in the internal environment of the housing to which microwaves are irradiated.

Accordingly, in the present invention, it is possible to condense the total amount of water vapor generated while the microwave is irradiated to the drying process, and to measure the water content of the wood that is currently being dried through the condensed water vapor content.

As described above, since the housing 2 is configured to be hermetically sealed, the loss of water vapor during drying can be prevented, so that the total amount of generated water vapor can be condensed.

In the present invention, excessive drying or overheating of the wood can be prevented by irradiating the microwave according to the water content of the wood by measuring the water content of the wood under drying. This will be described later.

At this time, the condenser 6 is provided with a water vapor collecting unit (not shown) for collecting water vapor, a condenser (not shown) for condensing the water vapor collected in the water vapor collecting unit, and a condenser (Not shown) for measuring the temperature of the condensate water.

The main body 110 may further include a wind-up portion 7 for cooling the housing. The wind-up portion 7 reaches the target moisture content and the dried wood is cooled to a predetermined temperature .

At this time, the power supply unit 7 can control the power supplied to the power supply unit through the power supply control unit 30. [

However, the present invention does not limit the presence or absence of the bulb 7.

Next, the control unit 120 includes an input unit 10 for inputting the type and size of the wood; A drying condition determining unit (20) for determining a drying condition according to the type and size of the wood inputted to the input unit (10); And a power supply controller 30 for supplying power to the power supply unit 3 according to the conditions of the drying condition determiner.

More specifically, the input unit 10 is configured to input the type and specification of the wood, so that it is possible to input species, specifications, initial moisture content, and target moisture content of the wood.

In this state, the input unit 10 transmits the input signal to the drying condition determining unit 20. At this time, the drying condition determining unit 20 preliminarily inputs the output application ratio of the microwave according to the kind of the wood An appropriate drying condition is determined according to the input value according to the characteristics of the wood transferred from the input unit 10. [

Then, the drying condition determining unit 20 determines drying conditions for each step and sends a signal to the power supply control unit 30 to control the ON / OFF operation of the power supply unit 3 installed in the main body 2. [

That is, the power supply control unit 30 receives a signal from the drying condition determination unit 20 and sends a signal to the power supply unit 3 installed in the main body 2, (4) so that the magnetron (4) emits microwaves.

In general, depending on the species, the difference in moisture content causes the drying speed and the drying time to be different. Therefore, a safe drying speed is required.

For example, pine trees have a 1% hr (1% water reduction per hour) level whereas 0.3% hr for oak trees. That is, in the case of pine tree, if the initial moisture content is 70% and the target moisture content is 20%, a drying time of at least 50 hours should be given. In the same case, oak must have a drying time of more than 150 hours. If drying is performed earlier than the above-mentioned time, ignition occurs due to overheating of the specific wood part due to excessive microwave energy input and concentration.

As a result, this safe drying rate is associated with the output application rate of the microwave.

Accordingly, in the present invention, the drying condition determining unit 20 determines the drying condition of the wood through the information of the safe drying speed depending on the type of wood, that is, the output application ratio of the microwave. ), Microwaves can be irradiated according to the kind of each wood.

Particularly, in the present invention, the drying condition determining unit 20 determines appropriate microwave drying conditions according to the drying state of the wood during the process of drying the wood, and transfers the drying conditions to the power supply control unit 30 , Excessive drying or overheating of the wood can be prevented.

That is, as described above, in the present invention, since the content of water vapor generated during the process of drying the wood can be calculated through the condenser 6 and the water content of the dried wood can be measured, It is possible to determine an appropriate microwave drying condition according to the drying condition of the wood.

1, the control unit 120 includes a receiving unit 40 for receiving a signal input from the main body 110, and supplies the received signal to the drying condition determining unit 20, And a signal transmission unit 50 for transmitting the signal to the base station.

That is, the receiving unit 40 transmits the information about the temperature inputted from the temperature sensor 5 of the main body 110 to the drying condition determining unit 20 through the signal transmitting unit 50, The drying condition determining unit 20 can provide information necessary for determining the drying conditions.

As described above, the temperature sensor 5 is disposed at a predetermined interval in the wood 1, and during the process of drying the wood, the temperature is detected by the position of the wood so that an overheating phenomenon occurs at a specific position of the wood Or not.

That is, in the process of drying the wood, the temperature sensed by the temperature sensor 5 is checked. When the temperature of the wood exceeds the set temperature, the magnetron 4 close to the temperature sensor 5, It is possible to prevent the ignition of a specific part of the logs due to the overheating of the wood, thereby achieving the best wood drying.

Thereafter, the signal transmission unit 50 continuously checks the temperature of the specific part of the wood transmitted to the receiving unit 40, and when the internal temperature of the specific part of the wood is cooled and reaches the set minimum temperature, The signal transmission unit 50 transmits the information to the drying condition determination unit 20 and the drying condition determination unit 20 sends a signal to the power supply control unit 30 to turn on the magnetron 4, To turn the microwave to the relevant part of the wood.

The receiving unit 40 may transmit the information on the amount of water vapor input from the condensing unit 5 of the main body 110 to the drying condition determining unit 20 through the signal transmitting unit 50 , The drying condition determining unit 20 can provide information necessary for determining the drying conditions.

That is, as described above, in the present invention, the moisture content of the dried wood is measured by calculating the content of water vapor generated during the process of drying the wood through the condenser 6, The drying condition determining unit 20 can determine an appropriate microwave drying condition according to the state of the dried wood by receiving the drying condition determining unit 20 and receiving the drying condition determining unit 20. [

Hereinafter, a control method of the wood drying process using the microwave according to the present invention will be described.

FIG. 2 is a schematic flow chart for explaining a method of controlling a wood drying process using microwaves according to the present invention.

Referring to FIG. 2, a control method of a wood drying process using a microwave according to the present invention includes a step of measuring an initial water content of a wood (S110).

The initial moisture content is different for each species of wood, and the initial moisture content may be different even if they are the same species.

The initial moisture content can be measured by the following equation (1).

... 수학식 (1)

... Equation (1)

(Where Mi is the initial moisture content (% db), Wo is the total dry weight (kg) and Wi is the initial weight of the wood (kg)).

At this time, the total dry weight (kg) as Wo can be calculated through the basic density (Db, kg / m3) of the wood to be dried and can be measured through the following equation (2).

... 수학식 (2)

&Quot; (2) "

(Where Db is the basic density (kg / m 3) of the wood to be dried and Vi is the volume of the dry mass (m 3)).

This total dry weight may have a unique value depending on the wood to be dried.

That is, as described with reference to FIG. 1, the type and specification of the wood, for example, the species and specification of the wood, the initial moisture content, and the target moisture content can be inputted through the input section 10 of the control section 120. [

Next, a method of controlling the drying process of the wood using the microwave according to the present invention includes a step of first drying the wood by irradiating the first microwave according to the initial moisture content (S120).

More specifically, the conditions for drying the wood are determined according to the information according to the initial moisture content, and the wood can be dried by irradiating the first microwave according to the conditions.

1, the drying condition determining unit 20 determines the drying condition of the wood material to be supplied from the input unit 10 based on the type of the wood material, the initial moisture content, The appropriate drying condition is determined according to the input value according to the following equation.

On the other hand, in determining the drying condition for irradiating the first microwave, the permeability index of the wood to be dried can be taken into consideration. By inputting the permeability index through the input unit, the drying condition determining unit determines the drying condition of the wood Can be applied as a function.

The permeability index is an index indicating a state in which moisture penetrates into the wood under a resultant force of a constant wet steam. A high permeability index means that it is difficult for the microwave to penetrate into the wood, and the low permeability index It is easy for the microwave to penetrate into the inside of the wood.

1, in the process of drying the wood by irradiating the first microwave, the temperature sensor 5 is arranged at a predetermined interval in the wood 1, and during the process of drying the wood, It is possible to determine whether or not an overheating phenomenon occurs at a specific position of the wood. Since this is the same as described above, a detailed description will be omitted.

Next, the control method of the wood drying process using the microwave according to the present invention includes a step of measuring the moisture content of the first dried wood during drying (S130).

As described above with reference to Fig. 1, in the present invention, the content of water vapor generated during the process of drying wood is calculated through the condenser 6, and the moisture content of the dried wood can be measured. Through the water content of the wood, it is possible to determine the appropriate microwave drying conditions according to the drying condition of the wood.

The water content during drying can be measured by the following equation (3).

... 수학식 (3)

... (3)

(Where Mn is the moisture content during drying (% db), Wo is the total dry weight (kg), Wi is the initial weight of the wood (kg) and Wd is the weight of the condensate)

At this time, the weight of the condensed water as Wd can be calculated by collecting water vapor through the water vapor collecting unit, condensing the water vapor collected in the water vapor collecting unit through the condenser, and measuring the weight of the condensed water condensed in the condenser.

The moisture content in the drying is transferred to the receiving unit 40 of FIG. 1 and inputted to the drying condition determining unit 20 through the signal transmitting unit 50, The drying conditions of the microwave are determined.

Next, the method for controlling the drying process of the wood using the microwave according to the present invention includes a step of drying the wood by the second microwave according to the water content during the drying (S140).

More specifically, the conditions for drying the wood are determined according to the information according to the water content during drying, and the wood can be dried by irradiating the second microwave according to the conditions.

1, the drying condition determining unit 20 determines the drying condition of the wood material to be supplied from the input unit 10 because the application ratio of the output of the microwave according to the kind of the wood, The appropriate drying conditions are determined according to the input values according to the following equation.

In this case, in determining the drying condition for irradiating the second microwave, the permeability index of the wood to be dried can be taken into consideration. By inputting the permeability index through the input unit, the drying condition determining unit determines the drying condition of the wood Can be applied as a function. Since this is the same as described above, a detailed description will be omitted.

In the drying condition determining unit, the output application ratio of microwaves may be input as shown in Table 1 below.

However, Table 1 shows only one example. Depending on the type of wood, the water content of the wood, the permeability index of the wood, etc., the output application ratio of the microwave may be different.

Moisture content Microwave power application ratio Permeability index A (high) Permeability index B (low) Initial moisture content ~ 30% 100% to 75% 75% to 50% 30% to 20% 75% to 50% 50% to 25% 20% to 15% 50% to 25% 25% to 12.5% 15% to 10% Less than 25% Less than 12.5%

For example, in step S110, when the initial moisture content of the wood to be dried is 50% and the permeability index is A, the output application ratio of the microwave is 100% to 75%, and then the primary dried wood When the water content is 25%, the microwave output application ratio is 75% to 50%.

1, in the process of drying the wood by irradiating the second microwave, the temperature sensor 5 is arranged at a predetermined interval in the wood 1, and during the process of drying the wood, It is possible to determine whether or not an overheating phenomenon occurs at a specific position of the wood. Since this is the same as described above, a detailed description will be omitted.

Subsequently, when the moisture content of the wood does not reach the target moisture content, the steps of S130 and S140 described above are continued. When the moisture content of the wood reaches the target moisture content, the drying step is terminated, The drying process of the wood is completed by cooling the dried wood to a predetermined temperature through the air blowing unit described with reference to FIG.

As described above, according to the present invention, the moisture content of the dried wood can be measured by calculating the content of water vapor generated during the process of drying the wood through the condenser, , Excessive drying or overheating of the wood can be prevented.

Further, in determining the drying conditions for irradiating the microwaves, by considering the permeability index of the wood to be dried, more accurate drying conditions of the wood can be determined according to the characteristics of the wood.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (6)

Measuring an initial moisture content of the wood;
Irradiating the first microwave according to the initial moisture content to dry the wood first;
Measuring the moisture content during drying of the first dried wood; And
And second drying the wood by irradiating a second microwave according to the water content during drying,
The moisture content of the first dried wood is measured by measuring the moisture content of the first dried wood through the condenser for condensing the steam generated during the first drying of the wood,
Wherein the condenser comprises: a water vapor collecting part for collecting the water vapor; A condenser for condensing the water vapor collected in the water vapor collecting unit; And a condensate weigher for measuring the weight of the condensed water condensed in the condenser,
Wherein the moisture content of the first dried wood is measured through the condensing unit to calculate the content of water vapor generated during the first drying of the wood to measure the moisture content of the first dried wood. The method according to claim 1,
Wherein the initial moisture content is measured by the following equation (1).

... Equation (1)
(Where Mi is the initial moisture content (% db), Wo is the total dry weight (kg) and Wi is the initial weight of the wood (kg)). 3. The method of claim 2,
Wherein the total dry weight (kg) as Wo is measured by the following equation (2).

&Quot; (2) "
(Where Db is the basic density (kg / m 3) of the wood to be dried and Vi is the volume of the dry mass (m 3)). The method according to claim 1,
Wherein the water content during drying is measured through the following equation (3): < EMI ID = 3.0 >

... (3)
(Where Mn is the moisture content during drying (% db), Wo is the total dry weight (kg), Wi is the initial weight of the wood (kg) and Wd is the weight of the condensate) A wood drying apparatus using a microwave, comprising a main body for drying wood and a control unit for controlling the main body,
Wherein,
A housing having a space capable of accommodating the wood;
A plurality of magnetrons for drying the wood contained in the housing;
A power supply unit for supplying power to the magnetron;
A plurality of temperature sensors for sensing the temperature of the wood being changed during the process of drying the wood; And
And a condensing portion for condensing the water vapor generated during the process of drying the wood,
Wherein the condenser comprises: a water vapor collecting part for collecting the water vapor; A condenser for condensing the water vapor collected in the water vapor collecting unit; And a condensate weigher for measuring the weight of the condensed water condensed in the condenser,
And a moisture content of the steam generated during the drying process of the wood through the condenser is calculated to measure the water content of the dried wood. delete

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