JP6211984B2 - Heated object load estimation device for microwave heating, microwave heating device, and heated object load estimation method for microwave heating - Google Patents

Description

  The present invention relates to a load estimation device for a heated object related to microwave heating, a microwave heating device, and a load estimation method for a heated object related to microwave heating.

  A microwave heating apparatus for heat-treating an object to be heated is known (for example, see Patent Document 1). The microwave heating device has, for example, a magnetron. The microwave emitted from the magnetron is supplied to the chamber through a waveguide or the like, and heats an object to be heated in the chamber.

  A portion of the microwave that is not absorbed by the object to be heated in the chamber is reflected in the chamber and travels back to the magnetron. Since this microwave causes deterioration of the magnetron, it is preferable that the microwave does not reach the magnetron. Note that there are cases where a microwave oven for home use does not employ a configuration that suppresses the return of microwaves from the chamber to the magnetron due to cost constraints.

  On the other hand, industrial microwave heating apparatuses are often provided with a configuration for suppressing the return of microwaves from the chamber to the magnetron. Specifically, the industrial microwave heating apparatus includes a power monitor, a tuner, and an isolator in addition to the magnetron.

  The power monitor displays the intensity of the microwave emitted from the magnetron and the intensity of the microwave reflected from the chamber toward the magnetron (reflected microwave). The operator minimizes the reflected microwave by adjusting the tuner stub while watching the power monitor. The intensity of the reflected microwave varies depending on the intensity of the microwave from the magnetron. Further, the intensity of the reflected microwave also changes due to a change in the microwave absorption characteristics of the object to be heated due to a temperature change, and therefore changes during the heat treatment of the object to be heated. For this reason, when the reflected microwave is strong, the dummy load included in the isolator absorbs the microwave from the chamber. Thereby, the reflection of the microwave to a magnetron is suppressed and the damage of a magnetron is suppressed.

JP 2004-71269 A

  In order to improve the efficiency of the heat treatment of the object to be heated using microwave heating and the accuracy of temperature control, the microwave heating apparatus needs to grasp the load of the object to be heated with respect to the microwave heating. . The load in this case refers to microwave absorption characteristics of the object to be heated. However, in general, the load on the object to be heated with respect to microwave heating varies greatly depending on the material, and thus it is difficult to estimate the load. In the field of microwave heating devices, attempts to estimate the load of the object to be heated related to microwaves are not always active. In general, since the microwave absorption characteristics of a substance vary depending on the temperature of the substance, it is difficult to obtain appropriate heating conditions for the entire processing temperature range of the substance.

  As described above, in an industrial microwave heating apparatus having a power monitor, a tuner, and an isolator, an operator adjusts the stub of the tuner to minimize the reflected microwave. After this adjustment, the worker can estimate the load of the object to be heated with respect to the object to be heated based on the difference between the power of the incident microwave to the power monitor and the power of the reflected microwave. However, power monitors, tuners, and isolators are large in size and expensive. For this reason, the presence of a power monitor, a tuner, and an isolator is not preferable from the viewpoints of downsizing the device and reducing manufacturing costs.

  In view of the above circumstances, the present invention is capable of estimating the load of an object to be heated related to microwave heating with a simpler configuration, the load estimating apparatus for the object to be heated related to microwave heating, the microwave heating apparatus, And it aims at providing the load estimation method of the to-be-heated material regarding a microwave heating.

(1) In order to solve the above problems, a load estimation device for a heated object related to microwave heating according to an aspect of the present invention detects a leaked microwave as a microwave leaking from a chamber containing the heated object. The leakage microwave detection unit, and the microwave heating based on a predetermined relationship indicating a relationship between the supply microwave as the microwave emitted toward the chamber and the leakage microwave. A load estimating unit that estimates a load of a heated object, and the load estimating unit estimates an equivalent mass of the reference material when the object to be heated is replaced with a predetermined reference material as the load, A reference relationship indicating a relationship between the supply microwave and a leakage microwave when the reference material is disposed in the chamber instead of the object to be heated, and the predetermined relationship. And calculating the equivalent mass, and the supply at the inflection point where the ratio of the change in the strength of the leakage microwave to the change in the strength of the supply microwave changes in the predetermined relationship. A unit at an inflection point when the intensity of the microwave is defined as Pw and the ratio of the change in the intensity of the leaked microwave to the change in the intensity of the supply microwave in the reference relation changes. If the supply microwave intensity applied to said reference substance per mass was defined as PD _R, the load estimation unit, the equivalent mass We you calculated by the equation We = Pw / PD _R.

  Note that the load of the object to be heated with respect to microwave heating refers to the absorption characteristics of the microwave in the object to be heated. In other words, the load refers to the heating characteristic of the object to be heated with respect to microwave heating.

  According to this configuration, based on a predetermined relationship indicating the relationship between the supply microwave and the leakage microwave, the load estimation unit loads the object to be heated with respect to microwave heating (hereinafter, also simply referred to as the object to be heated). Is estimated. With such a configuration, the load estimation unit can easily know the output of the supplied microwave based on the output of the microwave generation source. Further, the load estimation unit can easily know the leakage microwave using the leakage microwave detection unit. With such a simple configuration, the load estimation device can estimate the load of the object to be heated. Therefore, the load estimation apparatus does not need to use a large apparatus such as a power monitor, a tuner, and an isolator, and can estimate the load of the object to be heated with a simpler configuration.

Furthermore , the load estimation unit estimates an equivalent mass of the reference material when the object to be heated is replaced with a predetermined reference material as the load.

  According to this configuration, the load estimation unit estimates the load of the object to be heated using the equivalent mass of the reference material. Thereby, the load estimation part can unify the calculation method of the load of a to-be-heated object irrespective of the material of a to-be-heated object. As a result, for example, creation of a heating pattern (recipe) for an object to be heated during microwave heating becomes easier.

Further , the load estimation unit includes a reference relationship indicating a relationship between the supply microwave and the leakage microwave when the reference material is disposed in the chamber instead of the object to be heated, and the predetermined relationship. Based on the above, the equivalent mass is calculated.

  According to this configuration, the load estimation unit can calculate the equivalent mass by comparing the reference relationship with the predetermined relationship.

Further , when the strength of the supplied microwave is defined as Pw at the inflection point where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supplied microwave in the predetermined relationship changes And the supply given to the reference material per unit mass at an inflection point where the ratio of the change in the intensity of the leaked microwave to the change in the intensity of the supply microwave in the reference relationship changes. If the intensity of the microwave is defined as PD _R, the load estimating unit calculates the equivalent mass We by the formula We = Pw / PD _R.

According to this configuration, when the strength of the microwave supplied to the object to be heated exceeds the value at the inflection point, the strength of the leakage microwave increases rapidly. That is, when the strength of the microwave supplied to the object to be heated exceeds the value at the inflection point, the number of microwaves that are not absorbed by the object to be heated increases, and as a result, the leakage microwave from the chamber increases rapidly. . This tendency is the same when the reference material is heated by microwaves. By using such a tendency, the load estimation unit can estimate the load of the object to be heated with reference to the inflection point. As a result, the load estimation unit can estimate the load capacity of the object to be heated more accurately.
(2) More preferably, the reference substance is water.
According to this configuration, the load estimation unit can estimate the equivalent mass of water corresponding to the load of the object to be heated. If it is water, it is easy to grasp the absorption characteristics of the microwave, and therefore the work for estimating the load of the object to be heated becomes easier.

( 3 ) In order to solve the above-described problem, a microwave heating apparatus according to an aspect of the present invention emits a predetermined supply microwave toward a chamber for accommodating an object to be heated and a space in the chamber. And a control unit that controls the microwave emitting unit based on the load estimated by the load estimating unit.

  According to this structure, a load estimation part estimates the load of a to-be-heated object based on the predetermined relationship which shows the relationship between a supply microwave and a leakage microwave. With such a configuration, the load estimation unit can easily know the output of the supplied microwave based on the output of the microwave generation source. Further, the load estimation unit can easily know the leakage microwave using the leakage microwave detection unit. With such a simple configuration, the load estimation device can estimate the load of the object to be heated. Therefore, the load estimation apparatus does not need to use a large apparatus such as a power monitor, a tuner, and an isolator, and can estimate the load of the object to be heated with a simpler configuration.

  Further, the control unit controls the microwave emitting unit based on the load value estimated by the load estimating unit. Thereby, the microwave emission part can supply a supply microwave to a to-be-heated object in the aspect matched with the load of the to-be-heated object. Thereby, the microwave emission part can supply a supply microwave to a to-be-heated material efficiently and accurately. As a result, the energy consumption efficiency of the microwave heating device and the accuracy of the heat treatment can be further increased.

( 4 ) In order to solve the above-described problem, a load estimation method for an object to be heated related to microwave heating according to an aspect of the present invention detects a leaked microwave as a microwave leaking from a chamber containing the object to be heated. The to-be-heated object related to microwave heating based on a predetermined relationship indicating a leakage microwave detection step and a relationship between a supply microwave as a microwave emitted toward the chamber and the leakage microwave estimating a load, the load estimating step, only contains the load estimating step, as the load, and estimates an equivalent mass of the reference substance if the object to be heated is replaced by a predetermined reference substance, the A reference relationship indicating a relationship between the supply microwave and the leakage microwave when the reference material is disposed in the chamber instead of the object to be heated; Based on the predetermined relationship, the equivalent mass is calculated, and at the inflection point where the ratio of the change in the leakage microwave strength to the change in the strength of the supplied microwave changes in the predetermined relationship. The inflection point when the strength of the supplied microwave is defined as Pw and the ratio of the change in the strength of the leaked microwave to the change in the strength of the supplied microwave changes in the reference relationship If the, the reference intensity of the supply microwaves applied to the material per unit mass was defined as PD _R by the load estimating step, to calculate the equivalent mass We by the formula We = Pw / PD _R The

  According to this configuration, the load on the object to be heated is estimated based on the predetermined relationship indicating the relationship between the supply microwave and the leakage microwave. With such a configuration, the output of the supply microwave is easily known based on the output of the microwave generation source. Also, leaky microwaves are easily known in the leaky microwave detection step. With such a simple configuration, the load on the object to be heated is estimated. Therefore, when estimating the load of the object to be heated, it is not necessary to use a large device such as a power monitor, a tuner, and an isolator, and the load of the object to be heated can be estimated with a simpler configuration.

  According to the present invention, it is possible to estimate the load of the object to be heated with respect to the microwave with a simpler configuration.

It is a front view of the microwave heating device concerning one embodiment of the present invention. It is a side view of a microwave heating device. It is sectional drawing of the principal part which follows the III-III line of FIG. It is a typical graph for demonstrating the relationship between a supply microwave and a leakage microwave. It is a flowchart for demonstrating an example of the flow of a process in a load estimation apparatus and a control part.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention can be widely applied as a load estimation device for a heated object related to microwave heating, a microwave heating device, and a load estimation method for a heated object related to microwave heating.

  FIG. 1 is a front view of a microwave heating apparatus 1 according to an embodiment of the present invention. FIG. 2 is a side view of the microwave heating apparatus 1. With reference to FIG. 1 and FIG. 2, the microwave heating apparatus 1 is used in order to heat the to-be-heated material 50 with a microwave. The object to be heated 50 may be an object heated by microwaves, and the material is not limited.

  The microwave heating device 1 includes a housing 2, a chamber 3, a magnetron 4 (4a, 4b, 4c, 4d), a waveguide 5, an inverter 6, a control box 7, a load estimating device 8, And a control unit 9.

  The housing | casing 2 is formed combining the metal plate, for example. In the present embodiment, the housing 2 is formed in a hollow quadrangular prism shape. The housing 2 accommodates a chamber 3, a magnetron 4, a waveguide 5, an inverter 6, and a control box 7. In addition, in the figure, the housing | casing 2 is shown with the dashed-two dotted line which is an imaginary line.

  Doors 11 and 12 are provided on the front surface of the housing 2. The door 11 is configured to allow the control box 7 to be exposed to the outside of the housing 2. The door 12 is configured to expose the chamber 3 to the outside of the housing 2. An observation window 13 is attached to the side wall of the housing 2 adjacent to the door 12. An operator can visually recognize the chamber 3 from the outside of the housing 2 through the observation window 13.

  The chamber 3 is provided to accommodate the object to be heated 50. In this embodiment, the chamber 3 is arrange | positioned in the intermediate part of the housing | casing 2 in the up-down direction. The chamber 3 is configured to reflect microwaves using a metal plate or the like. The chamber 3 is formed in a hollow box shape.

  3 is a cross-sectional view of the main part taken along the line III-III in FIG. 1 to 3, the chamber 3 includes four side walls 14, 15, 16, 17, a choke mechanism 18, a top wall 19, and a bottom wall 20.

  The side walls 14, 15, 16, and 17 are formed in a hollow quadrangular prism shape as a whole, and extend vertically. A window portion 21 is formed on the side wall 14.

  The window portion 21 is provided so that an operator can visually recognize the inside of the chamber 3 from the outside of the chamber 3. The window portion 21 is provided in a partial region of the side wall 14. The window part 21 is arrange | positioned in the approximate center of the side wall 14, and is formed in the rectangular shape.

  The window portion 21 is formed by using a part of the side wall 14 as punching metal. In the window portion 21, a large number of fine through holes having a periodic structure (a regularly arranged structure) are formed, so that the inside of the chamber 3 can be observed, but the micro-holes in the chamber 3 can be observed. The wave is configured not to leak outside beyond a predetermined reference value. Each said through-hole is formed in the round hole shape, for example. Needless to say, the allowable value of the amount of leakage of microwaves used for detecting microwaves is not more than the electromagnetic wave intensity guideline value indicated in the radio wave protection guideline. The above-mentioned radio wave protection policy is disclosed in “Protection policy for human body in radio wave use” (Advisory No. 38, Telecommunications Technology Council, June 1990).

  The door 12 is provided with a λ / 4 choke mechanism 18 (λ is the wavelength of the microwave). The choke mechanism 18 is provided to suppress leakage of the microwave supplied to the chamber 3. The space surrounded by the side walls 14, 15, 16, and 17 is covered with a top wall 19 from above.

  The ceiling wall 19 is formed in the shape which pushed up the center part of the metal plate so that it might become convex upwards, for example. The outer peripheral portion of the top wall 19 is fixed to the upper ends of the side walls 14, 15, 16, and 17. The top wall 19 faces the bottom wall 20 vertically.

  The bottom wall 20 is provided as a part where the article to be heated 50 is placed. The bottom wall 20 is formed in a substantially rectangular flat plate shape. The outer peripheral portion of the bottom wall 20 is connected to the side walls 14, 15, 16, and 17. As described above, the space surrounded by the bottom wall 20, the side walls 14, 15, 16, 17 and the top wall 19 is defined as a heating space 28 for heating the article to be heated 50. A plurality of openings 24, 25, 26, 27 are formed in the bottom wall 20.

  The openings 24, 25, 26, and 27 are provided as microwave inlets to the heating space 28, respectively. The openings 24, 25, 26, and 27 are arranged so as to surround the object to be heated 50 in plan view. In this embodiment, each opening part 24, 25, 26, 27 is formed in the elongate rectangular shape. The two openings 24 and 26 are arranged so as to sandwich the object to be heated 50 in a state where the directions are aligned in a plan view. Further, the opening 25 is arranged in a direction shifted by 90 ° from the direction of the opening 24 in plan view. Similarly, the opening 27 is disposed in a direction shifted by 90 ° from the direction of the opening 24 in plan view. The openings 25 and 27 are arranged so as to sandwich the object to be heated 50 in plan view. The openings 24, 25, 26, and 27 are connected to the corresponding waveguides 5, respectively.

  Each waveguide 5 is provided to guide microwaves from the corresponding magnetrons 4 a, 4 b, 4 c, 4 d to the heating space 28 of the chamber 3. Each waveguide 5 extends downward from the bottom wall 20 of the chamber 3 and is connected to the corresponding magnetron 4a, 4b, 4c, 4d.

  The magnetron 4 (4a, 4b, 4c, 4d) is provided in order to generate the microwave given to the article 50 to be heated. In the present embodiment, four magnetrons 4a, 4b, 4c, and 4d are provided. In addition, the number of magnetrons should just be one or more, and is not specifically limited. The magnetron 4 is an example of the “microwave emitting unit” in the present invention. In the present embodiment, the magnetrons 4a, 4b, 4c, and 4d are collectively referred to as magnetrons 4. In the present embodiment, a configuration in which microwaves are generated using the magnetron 4 will be described, but this need not be the case. For example, the article to be heated 50 may be heated by microwaves generated using a semiconductor.

  Each magnetron 4a, 4b, 4c, 4d is supported by the housing 2. Each magnetron 4 a, 4 b, 4 c, 4 d is configured to emit microwaves toward the heating space 28 via the corresponding waveguide 5. As a result, the microwaves from the magnetrons 4a, 4b, 4c, and 4d reach the heating space 28 through the corresponding waveguides 5 and heat the object to be heated 50. The magnetron 4 is connected to the inverter 6.

  The inverter 6 is provided to supply power to the magnetron 4. The inverter 6 is connected to a commercial power source or the like. The inverter 6 supplies AC power for generating microwaves to the magnetron 4. The inverter 6 and the magnetron 4 are controlled by the control unit 9.

  The controller 9 is configured to control the heating amount of the article to be heated 50. In the present embodiment, the control unit 9 is a computer having a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). An example of control by the control unit 9 will be described later. The control unit 9 is accommodated in the control box 7.

  The control box 7 is provided to accommodate devices related to the control of the microwave heating device 1. In the present embodiment, the control box 7 is disposed above the chamber 3. An operation panel 29 is attached to the door 11 located in front of the control box 7. The operation panel 29 includes, for example, a power switch and is exposed to the outside of the housing 2. The operation panel 29 outputs a predetermined signal to the control unit 9 or the like by being operated by an operator, for example.

  The control unit 9 controls the magnetron 4 based on the signal output from the operation panel 29 and the load of the heated object 50 related to the microwave heating estimated by the load estimating device 8. The object 50 is subjected to heat treatment.

  Note that the load of the object to be heated 50 related to microwave heating refers to microwave absorption characteristics of the object to be heated 50 related to microwave heating. In other words, the said load means the heating characteristic of the to-be-heated material 50 regarding microwave heating. Hereinafter, the load of the object to be heated 50 related to microwave heating is also simply referred to as the load of the object to be heated 50.

  The load estimation device 8 is provided for estimating the load of the object to be heated 50. In this embodiment, as will be described later, the load estimation result of the load estimation device 8 is used in the microwave output control by the control unit 9. As a result, the efficiency and accuracy with which the supply microwave as the microwave applied from the magnetron 4 to the heated object 50 in the heating space 28 is absorbed by the heated object 50 are further increased. Thereby, the microwave heating device 1 can suppress outputting useless microwaves that do not contribute to heating of the object to be heated 50.

  The load estimation device 8 includes a leakage microwave detection unit 31 and a load estimation unit 32.

  The leakage microwave detection unit 31 is provided to detect leakage microwaves as microwaves leaking from the chamber 3 in which the object to be heated 50 is accommodated. Leakage microwave detection unit 31 includes, for example, an antenna for receiving microwaves. In the present embodiment, the leakage microwave detection unit 31 is disposed adjacent to the window portion 21 in the housing 2 and detects leakage microwave leaking from the window portion 21. The leaky microwave detection unit 31 may be disposed adjacent to the choke mechanism 18. Also in this case, the leakage microwave detection unit 31 detects the leakage microwave from the chamber 3.

The size of the leakage microwave detection unit 31 is set to be smaller than the size of the window portion 21 in the present embodiment. The leaky microwave detection unit 31 outputs a signal for specifying the strength (mW / cm ² ) of leaky microwave per unit area on the microwave detection surface of the leaky microwave detection unit 31 to the load estimation unit 32. To do. In the present embodiment, the intensity (mW / cm ² ) of leakage microwave per unit area is also simply referred to as the intensity of leakage microwave.

  The load estimation unit 32 is configured to estimate the load of the object to be heated 50 based on the magnitude of the leaking microwave. The load estimation unit 32 is accommodated in the control box 7. The load estimation unit 32 may be configured as software by a computer including a CPU, a RAM, and a ROM, or may be configured as hardware using an electric circuit. When the load estimation unit 32 is configured by a computer, the load estimation unit 32 may be configured by the same computer as the control unit 9 or may be configured by a computer different from the control unit 9. .

  The load estimation unit 32 estimates the load of the object to be heated 50 based on a predetermined relationship. The “predetermined relationship” is a relationship indicating a relationship between the supply microwave and the leakage microwave when the microwave heating apparatus 1 heats the article 50 to be heated by the microwave. Moreover, in this embodiment, the load estimation part 32 estimates the load of the to-be-heated material 50 using a reference | standard relationship in addition to the said predetermined relationship. The “reference relationship” is a relationship indicating the relationship between the supply microwave and the leakage microwave when the microwave heating apparatus 1 heats water with microwaves. In other words, the reference relationship indicates a relationship between the supply microwave and the leakage microwave when water having a predetermined mass is disposed in the chamber 3 instead of the object to be heated 50. Water is an example of the “reference substance” in the present invention.

FIG. 4 is a schematic graph for explaining the relationship between the supply microwave and the leakage microwave. Next, the relationship between the supply microwave and the leakage microwave will be described. 2 and 4, the horizontal axis of the graph represents the total output ratio of the magnetron 4 (4a, 4b, 4c, 4d), and indicates the output of the magnetron 4 with respect to the rated output of the magnetron 4 as a percentage. Yes. That is, the horizontal axis of the graph indicates the strength of the supplied microwave. The vertical axis of the graph indicates the strength of the leaky microwave, and the unit is mW / cm ² .

  In FIG. 4, reference graphs BG (BG1 to BG3) are shown as graphs indicating the reference relationship. In the present embodiment, one reference graph BG indicates one reference relationship. In the present embodiment, the reference graph BG is created in advance by experiments or the like. Note that the reference graph BG shown in FIG. 4 is schematically displayed, and does not strictly display actual experimental results.

  The reference graph BG1 shows the relationship (reference relationship) between the supply microwave and the leakage microwave when 1 kg of water is placed in the chamber 3. Here, when the microwave is supplied to 1 kg of water, the case where the output of the supply microwave from the magnetron 4 increases from zero is considered. At this time, initially, as indicated by the region R11 of the reference graph BG1, the change in the intensity of the leakage microwave with respect to the change in the output of the supply microwave is small. This indicates that most of the supply microwave from the magnetron 4 is absorbed by water. Note that the lower limit of the supply microwave output in the region R11 is zero, and the upper limit of the output is the microwave output at an inflection point A1 described later.

In the reference graph BG1, when the output of the supply microwave is about 19%, there is an upper limit of the region R11, and the ratio of the change in the leakage microwave intensity with respect to the change in the supply microwave intensity is changed. Yes. That is, in the reference graph BG1, an inflection point A1 exists at a location where the output of the supplied microwave is about 19%. Further, in the inflection point A1, the energy supply microwave per unit _mass, is defined as a _PD R (PD _R1). In the present embodiment, the inflection point does not indicate an output at one exact point of the supplied microwave, but is a value having a certain width with respect to the output of the supplied microwave.

In the region R11, a label PD ₁ indicating that the energy (intensity) PD of the supply microwave per unit mass is PD = 1 (kW / kg) is described. That is, in the region R11, there is a region to which 1 kW of supply microwave is given per liter of water.

  When the microwave output is in the region R12 beyond the inflection point A1 that is the boundary between the region R11 and the region R12, the ratio of the increase in leakage microwave to the increase in the supply microwave output is , Larger than the ratio in the region R11. That is, the ratio of the strength of the leaked microwave to the change in the strength of the supplied microwave changes at the output of the supplied microwave when the strength of the supplied microwave is the strength at the inflection point A1. To do.

  As described above, the intensity P1 of the supply microwave at the inflection point A1 is the supply microwave at the inflection point of the ratio of the change in the strength of the leaked microwave to the change in the output (strength) of the supply microwave. Is equivalent to the strength of In the region R12, the microwave from the magnetron 4 cannot be sufficiently absorbed by water, and it is considered that the leaked microwave leaking from the window portion 21 increases.

  Similarly to the above, the reference graph BG2 shows the relationship (reference relationship) between the supply microwave and the leakage microwave when water having a mass of 2 kg is disposed in the chamber 3. In this case, similarly to the reference graph BG1, the regions R21 and R22 exist in the reference graph BG2. The regions R21 and R22 have the same characteristics as the corresponding regions R11 and R12, respectively. In the region R21, the change in the strength of the leakage microwave with respect to the change in the output of the supply microwave is small. Note that the lower limit of the supply microwave output in the region R21 is zero, and the upper limit of the output is the supply microwave output at the inflection point A2.

In the reference graph BG2, when the output of the supply microwave is about 38%, there is an upper limit of the region R21, and the ratio of the change in the leakage microwave intensity with respect to the change in the supply microwave intensity is changed. Yes. That is, in the reference graph BG2, the inflection point A2 exists at a place where the output of the supplied microwave is about 38%. Further, in the inflection point A2, the energy supply microwave per unit _mass, is defined as a _PD R (PD _R2). The inflection point A2 is a boundary between the region R21 and the region R22.

Incidentally, in the region R21, labeled PD ₂ is marked to indicate that the energy PD = 1 for supplying microwaves per unit mass (kW / kg). That is, in the region R21, there is a region to which 1 kW of supply microwave is given per liter of water.

  As described above, in the reference graph BG2, the leakage microwave with respect to the change in the strength of the supply microwave at the output of the supply microwave when the strength of the supply microwave is the strength at the inflection point A2. The ratio of strength changes.

  As described above, the strength P2 of the supply microwave at the inflection point A2 is the ratio of the supply microwave at the inflection point of the ratio of the change in the strength of the leaked microwave to the change in the output (strength) of the supply microwave. Corresponds to strength.

  Similarly to the above, the reference graph BG3 shows the relationship (reference relationship) between the supply microwave and the leakage microwave when water having a mass of 4 kg is disposed in the chamber 3. In this case, similarly to the reference graph BG1, regions R31 and R32 exist in the reference graph BG3. The regions R31 and R32 have the same characteristics as the corresponding regions R11 and R12, respectively. In the region R31, the change in the intensity of the leakage microwave with respect to the change in the output of the supply microwave is small. Note that the lower limit of the supply microwave output in the region R31 is zero, and the upper limit of the output is the supply microwave output at the inflection point A3.

In the reference graph BG3, when the output of the supply microwave is about 76%, there is an upper limit of the region R31, and the ratio of the change in the leakage microwave intensity with respect to the change in the supply microwave intensity is changed. Yes. That is, in the reference graph BG3, the inflection point A3 exists at a place where the output of the supplied microwave is about 76%. Further, in the inflection point A3, the energy supply microwave per unit _mass, is defined as a _PD R (PD _R3). The inflection point A3 is a boundary between the region R31 and the region R32.

Incidentally, in the region R31, is labeled PD ₃ are written to indicate that the energy PD = 1 for supplying microwaves per unit mass (kW / kg). That is, in the region R31, there is a region to which 1 kW of supply microwave is given per liter of water.

  As described above, in the reference graph BG3, the leakage microwave with respect to the change in the strength of the supply microwave at the output of the supply microwave when the strength of the supply microwave is the strength at the inflection point A3. The ratio of strength changes.

  As described above, the intensity P3 of the supply microwave at the inflection point A3 is equal to the ratio of the change in the intensity of the leaked microwave to the change in the output (strength) of the supply microwave. Corresponds to strength.

As is clear from the reference graphs BG1, BG2, and BG3, the supply microwave energy when the energy PD of the supply microwave per unit mass PD = PD _R (PD _R1 , PD _R2 , PD _R3 ) (kW / kg) The magnitude is proportional to the mass of water. More specifically, the strength of the supply microwave when PD = PD _R2 energy is applied to 2 liters of water is the strength of the supply microwave when PD = PD _R1 energy is applied to 1 liter of water. About twice as much. Similarly, the strength of the supply microwave when PD = PD _R3 energy is applied to 4 liters of water is about 4 times the strength of the supply microwave when PD = PD _R1 energy is applied to 1 liter of water. Is double.

  Therefore, from the ratio of the inflection points A1 to A3 and the inflection points in the graph showing the relationship between the supply microwave and the leakage microwave when the supply microwave is supplied to water of a predetermined mass, The predetermined mass is revealed. That is, when the supply microwave is supplied to the object to be heated 50, the strength of the supply microwave at the inflection point A4 in the graph G4 indicating the relationship between the supply microwave and the leakage microwave, and each of the reference graph BG The equivalent mass We becomes clear from the ratio with the strength of the supplied microwave at the inflection points A1 to A3. The equivalent mass We is an equivalent mass of water when the article to be heated 50 is replaced with water. That is, the load estimation unit 32 can estimate the equivalent mass We as the load of the object to be heated 50 related to the microwave.

For example, when the strength Pw of the supply microwave at the inflection point A4 in the graph G4 (predetermined relationship) is about 28.5% of the rated value of the supply microwave, the reference graph BG1 (reference relationship) from the relationship between the microwave power P1 (about 19%) in _{PD R, 28.5 (%) ÷} 19 (% / l) = is 1.5 liters, the equivalent weight We is, is 1.5 liters . That is, the equivalent mass We is represented by the following formula (1).

We = Pw (kW) / PD _R (kW / kg) (1)
Pw: strength of the supplied microwave at the inflection point A4 where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supplied microwave in the graph G4 (predetermined relationship) changes.

  As described above, the load estimation unit 32 calculates the equivalent mass We based on the reference relationship for water and the predetermined relationship for the article 50 to be heated.

  Data of each of the reference graphs BG1 to BG3 is stored in the load estimation unit 32. The load estimating unit 32 stores data of the reference graphs BG1 to BG3 as numerical data.

  The load estimation unit 32 is configured to calculate an equivalent mass We as a load of the object to be heated 50. Specifically, the load estimation unit 32 is connected to the control unit 9 and the leakage microwave detection unit 31. The load estimation unit 32 receives data specifying the output of the supply microwave from the control unit 9. Moreover, the load estimation part 32 receives the data which specify the output of a leaking microwave.

  Then, the load estimation unit 32 records the relationship between the supply microwave and the leakage microwave when the supply microwave is supplied to the object to be heated 50. Thereby, the load estimation part 32 produces the graph G4 which shows the relationship (predetermined relationship) between a supply microwave and a leakage microwave. That is, the load estimation unit 32 creates a graph G4 indicating the relationship between the supply microwave and the leakage microwave given to the workpiece 50. Note that the load estimation unit 32 may create a table indicating the strength of the supply microwave and the strength of the leakage microwave instead of actually creating the graph G4.

Then, the load estimating unit 32 searches for the inflection point A4 where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supplied microwave changes in the graph G4. Next, the load estimation unit 32 is based on the energy values PD _R1 , PD _R2 , and PD _R3 at the inflection points A1 to A3 in the reference graphs BG1 to BG3 and the output Pw of the supply microwave at the inflection point A4. Then, the above equation (1) is calculated. Thereby, the load estimation unit 32 calculates the equivalent mass We.

  Next, an example of the flow of processing in the load estimation device 8 and the control unit 9 will be described. FIG. 5 is a flowchart for explaining an example of the flow of processing in the load estimation device 8 and the control unit 9. In the following, when the description is made with reference to the flowchart, the drawings other than the flowchart are also referred to as appropriate.

  The process described below is performed, for example, after the heating operation of the object to be heated 50 by the microwave heating apparatus 1 is started in accordance with the operation of the operation panel 29 by the worker.

  Specifically, a heat treatment command in the microwave heating apparatus 1 is given to the control unit 9 due to the operation of the operation panel 29 by the worker. Thereby, the control part 9 starts generation | occurrence | production of a supply microwave by operating the magnetron 4 (step S1). This supply microwave is supplied into the chamber 3 and heating of the object to be heated 50 is started.

  Next, the leaking microwave detection unit 31 detects the leaking microwave leaking from the chamber 3 (step S2). Thereafter, the load estimation unit 32 reads the supplied microwave data and the leaked microwave data (step S3). More specifically, the load estimation unit 32 reads from the control unit 9 a signal that specifies the intensity of the supply microwave set by the control unit 9. In addition, the load estimation unit 32 reads a signal that specifies the strength of the leakage microwave from the leakage microwave detection unit 31.

  Next, the load estimation part 32 produces the graph G4 which shows the relationship between a supply microwave and a leakage microwave about the to-be-heated material 50 (step S4). In this case, the load estimation unit 32 reads each time step S3 is executed, and sets the strength of the supply microwave as the value on the horizontal axis and the strength of the leakage microwave as the value on the vertical axis. A graph G4 is created using a plurality of coordinates specified in each process of step S3. And the load estimation part 32 determines whether the inflection point A4 exists in the graph G4 regarding the to-be-heated material 50 (step S5).

  When the inflection point A4 does not exist in the graph G4 (NO in step S5), the load estimation unit 32 outputs a signal indicating that the inflection point A4 does not exist to the control unit 9 (step S6). . That is, when most of the supplied microwave is absorbed by the object to be heated 50 and the intensity of the leakage microwave is smaller than the intensity of the supplied microwave, the fact is notified from the load estimation unit 32 to the control unit. 9 is notified.

  In this case, the control unit 9 controls the magnetron 4 so that the output of the supply microwave increases (step S7). In this case, for example, the control unit 9 performs control to increase the output of the supply microwave from the magnetron 4 by several percent of the rated output of the supply microwave.

  Then, the leakage microwave detection unit 31 detects again the leakage microwave leaking from the chamber 3 (step S2). In addition, the load estimation unit 32 reads from the control unit 9 a signal that specifies the intensity of the supply microwave set by the control unit 9, and outputs a signal that specifies the strength of the leakage microwave to the leakage microwave detection unit 31. (Step S3).

  Next, the load estimation unit 32 creates a graph G4 indicating the relationship between the supply microwave and the leakage microwave (step S4). In this case, for example, the load estimation unit 32 plots a point at coordinates specified by the strength of the latest supplied microwave and the strength of the leaked microwave. Then, the load estimation unit 32 extends the graph G4 based on the graph G4 created in the previous step S4 and the points plotted this time.

  And the load estimation part 32 determines whether the inflection point A4 exists in the graph G4 regarding the to-be-heated material 50 (step S5). When the inflection point A4 does not exist in the graph G4 (NO in step S5), the processes of steps S6, S7, S2 to S5 described above are repeated. When the strength of the supplied microwave reaches the rated value of the supplied microwave before the inflection point A4 appears in the graph G4, the increase in the output of the supplied microwave is stopped in step S7. In this case, even if the intensity of the supply microwave is maximum, the article to be heated 50 can absorb most of the supply microwave.

  On the other hand, when the inflection point A4 appears in the graph G4 (YES in step S5), the load estimation unit 32 estimates the equivalent mass We (step S8). For example, the load estimation unit 32 calculates the equivalent mass We using the above-described equation (1). In this case, Pw in equation (1) is the strength of the supplied microwave at the inflection point A4.

  Next, the load estimating unit 32 notifies the calculated value of the equivalent mass We to the control unit 9 (step S9). The control unit 9 that has received this notification controls the output of the supply microwave from the magnetron 4 based on the equivalent mass We (step S10).

  As described above, according to the microwave heating apparatus 1, the load estimation unit 32 determines whether the load of the object to be heated 50 is based on the predetermined relationship (graph G4) indicating the relationship between the supply microwave and the leakage microwave. Equivalent mass We) is estimated. With such a configuration, the load estimation unit 32 can easily know the output of the supply microwave based on the output of the magnetron 4. Further, the load estimation unit 32 can easily know the leakage microwave using the leakage microwave detection unit 31. With such a simple configuration, the load estimation device 8 can estimate the load of the object to be heated 50. Therefore, the load estimation device 8 does not need to use a large device such as a power monitor, a tuner, and an isolator, and can estimate the load of the object to be heated 50 with a simpler configuration.

  Moreover, according to the microwave heating apparatus 1, it is not the structure which consumes an unnecessary microwave (microwave reflected from the to-be-heated material 50) with an isolator. Therefore, the microwave is not consumed unnecessarily by the isolator, and the energy saving performance of the microwave heating apparatus 1 can be further increased. Furthermore, as a result of efficient absorption of microwaves by the object to be heated 50, the temperature of the object to be heated 50 in the microwave heating apparatus 1 can be controlled more precisely.

  Moreover, according to the microwave heating apparatus 1, the load estimation part 32 estimates the equivalent mass We of water at the time of replacing the to-be-heated material 50 with water. According to this structure, the load estimation part 32 estimates the load of the to-be-heated material 50 using the equivalent mass We of water. Thereby, the load estimation part 32 can unify the calculation method of the load of the to-be-heated object 50 irrespective of the material of the to-be-heated object 50. FIG. As a result, for example, it becomes easier to create a heating pattern (recipe for specifying a processing amount, a temperature increase rate, etc.) of the article to be heated 50 during microwave heating.

  Moreover, the load estimation part 32 can estimate the equivalent mass We of water corresponding to the load of the article 50 to be heated. If it is water, since it is easy to grasp the absorption characteristics of the microwave, the work for estimating the load of the object to be heated 50 becomes easier.

  In addition, according to the microwave heating apparatus 1, the load estimation unit 32 is configured such that the reference relationship (relationship between the supply microwave and the leakage microwave when water is disposed in the chamber 3 instead of the object to be heated 50 ( Based on the reference graphs BG1 to BG3) and a predetermined relationship (graph G4), the equivalent mass We is calculated. According to this configuration, the load estimation unit 32 can calculate the equivalent mass We by comparing the reference relationship with the predetermined relationship.

More specifically, the load estimating unit 32, the equivalent mass We, calculated by the formula We = Pw / PD _R. According to this configuration, when the strength of the microwave supplied to the object to be heated 50 exceeds the value at the inflection point A4, the strength of the leakage microwave increases rapidly. That is, when the strength of the microwave supplied to the object to be heated 50 exceeds the value Pw at the inflection point A4, more microwaves are not absorbed by the object to be heated 50, and as a result, leakage microwaves from the chamber 3 Increases rapidly. This tendency is the same when water is microwave-heated. By using such a tendency, the load estimation unit 32 can estimate the load (equivalent mass We) of the object to be heated 50 with reference to the inflection point A4. As a result, the load estimation unit 32 can estimate the load of the article to be heated 50 more accurately.

  Further, according to the microwave heating apparatus 1, the control unit 9 controls the magnetron 4 based on the load value (equivalent load We) of the article 50 to be heated estimated by the load estimation unit 32. Thereby, the magnetron 4 can supply the supply microwave to the object to be heated 50 in a mode that matches the load of the object to be heated 50. Thereby, the magnetron 4 can supply the supply microwave to the object to be heated 50 efficiently and accurately. As a result, the energy consumption efficiency of the microwave heating apparatus 1 and the accuracy of the heat treatment can be further increased.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment. The present invention can be variously modified as long as it is described in the claims.

  (1) For example, in the above-described embodiment, the load estimation device 8 has been described as an example in which the load estimation device 8 is provided as a part of the microwave heating device 1. However, this need not be the case. For example, the load estimation device 8 may be provided separately from the microwave heating device.

  (2) Further, in the above-described embodiment, an example has been described in which water is used as a reference material serving as a reference for calculating the equivalent mass We. However, this need not be the case. For example, the reference substance may be a substance other than water.

  The present invention can be widely applied as a load estimation device for a heated object related to microwave heating, a microwave heating device, and a load estimation method for a heated object related to microwave heating.

1 Microwave heating device 3 Chamber 4 Magnetron (microwave launcher)
8 Load estimation device 9 Control unit 28 Heating space (space in the chamber)
31 Leakage microwave detection unit 32 Load estimation unit 50 Object to be heated A4 Inflection point BG Reference graph (reference relationship)
G4 graph (predetermined relationship)
We equivalent mass (load)

Claims (4)

A leakage microwave detection unit for detecting leakage microwaves as microwaves leaking from a chamber containing an object to be heated;
A load estimation unit that estimates a load of the object to be heated related to microwave heating based on a predetermined relationship indicating a relationship between a supply microwave as a microwave emitted toward the chamber and a leakage microwave When,
Equipped with a,
The load estimating unit estimates an equivalent mass of the reference material when the object to be heated is replaced with a predetermined reference material as the load, and the reference material is disposed in the chamber instead of the object to be heated. Based on the reference relationship indicating the relationship between the supply microwave and the leakage microwave when being, and the predetermined relationship, to calculate the equivalent mass,
When the strength of the supplied microwave is defined as Pw at an inflection point where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supplied microwave in the predetermined relationship changes, and,
The strength of the supply microwave given to the reference material per unit mass at the inflection point where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supply microwave in the reference relationship changes. If it was defined as PD _R is,
The load estimating unit is characterized that you calculate the equivalent mass We by the formula We = Pw / PD _R, the load estimator of the object to be heated for Microwave heating. A load estimation device for a heated object related to microwave heating according to claim 1 ,
The apparatus for estimating a load of a heated object related to microwave heating, wherein the reference material is water. A chamber for containing an object to be heated;
A microwave emitting unit for emitting a predetermined supply microwave toward a space in the chamber;
A load estimation device for an object to be heated related to microwave heating according to claim 1 or 2 ,
Based on the load estimated by the load estimation unit, a control unit for controlling the microwave emitting unit,
A microwave heating apparatus comprising: A leakage microwave detection step for detecting leakage microwaves as microwaves leaking from a chamber containing an object to be heated;
A load estimation step of estimating a load of the heated object related to microwave heating based on a predetermined relationship indicating a relationship between a supply microwave as a microwave emitted toward the chamber and a leaked microwave When,
Only including,
The load estimating step estimates an equivalent mass of the reference material when the object to be heated is replaced with a predetermined reference material as the load, and the reference material is placed in the chamber instead of the object to be heated. Based on the reference relationship indicating the relationship between the supply microwave and the leakage microwave when being, and the predetermined relationship, to calculate the equivalent mass,
When the strength of the supplied microwave is defined as Pw at an inflection point where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supplied microwave in the predetermined relationship changes, and,
The strength of the supply microwave given to the reference material per unit mass at the inflection point where the ratio of the change in the strength of the leaked microwave to the change in the strength of the supply microwave in the reference relationship changes. If it was defined as PD _R is,
The load estimating step is characterized that you calculate the equivalent mass We by the formula We = Pw / PD _R, load estimation method of the object to be heated for Microwave heating.

Images