Dryer

Abstract

Provided is technology for more appropriately controlling a dryer. A dryer (1) comprises: a housing part (3) that houses a drying object; an antenna (8) that radiates microwaves onto the drying object housed in the housing part (3); and a microwave intensity detection unit (21) that detects the intensity of the microwaves by detecting the temperature of an absorber that absorbs the microwaves and generates heat. The microwave intensity detection unit (21) is provided at a position which is in the interior of the housing part (3) and at which the absorption of microwaves by the microwave intensity detection unit (21) does not inhibit the propagation of microwaves by the antenna (8).

Description

Dryer

[0001] The present disclosure relates to a dryer for drying an object to be dried.

[0002] As a method for accelerating the drying performance of a clothes dryer or a washing and drying machine, there is a method of using microwaves as a heat source for heating the moisture of clothes. The heating method using microwaves is widely used in a microwave oven (for example, see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 6-138159

[0004] As drying progresses, the amount of moisture that absorbs microwaves in the clothes, which are the objects to be dried, decreases, so the intensity of microwaves inside the dryer increases. In order to prevent the objects to be dried from being damaged by over-drying, it is necessary to appropriately control the intensity of microwaves.

[0005] The present disclosure provides a technique for more appropriately controlling a dryer.

[0006] The dryer in the present disclosure includes a housing portion for housing an object to be dried, a placement portion provided inside the housing portion for placing the object to be dried and having a plurality of holes through which air passes, a microwave irradiation portion for irradiating microwaves inside the housing portion, a circulation air passage for allowing the internal air containing water vapor evaporated by heating the object to be dried with microwaves to flow out of the housing portion, discharging moisture, and then flowing in, a microwave intensity detection portion for detecting the intensity of microwaves, and a control device having a moisture amount estimation portion for estimating the amount of moisture contained in the object to be dried based on the detection result of the microwave intensity detection portion. The microwave intensity detection portion is provided on the inner surface of the housing portion near the placement portion, and the control device is configured to adjust the output of microwaves based on the change in the estimated moisture amount.

[0007] According to the technique of the present disclosure, the dryer can be more appropriately controlled.

[0008] A schematic cross-sectional diagram illustrating the configuration of the dryer according to Embodiment 1. A schematic cross-sectional diagram illustrating another example of the configuration of the dryer according to Embodiment 1. A schematic cross-sectional diagram illustrating another example of the configuration of the dryer according to Embodiment 1. A diagram showing the microwave flow in the dryer. A diagram showing an example of an object to be dried. A diagram showing an example of an object to be dried during the drying process. A functional configuration diagram of the control device for the dryer according to Embodiment 1. A flowchart showing the procedure for drying operation.

[0009] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted.

[0010] The attached drawings and the following description are provided to enable a person skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) Embodiment 1 will be described below with reference to Figures 1 to 8.

[0012] [1-1. Configuration] Figure 1 is a schematic cross-sectional view showing the configuration of the dryer according to Embodiment 1. Figure 2 is a schematic cross-sectional view showing another example of the configuration of the dryer according to Embodiment 1. Figure 3 is a schematic cross-sectional view showing yet another example of the configuration of the dryer according to Embodiment 1. The dryer 1 of this embodiment has the function of drying objects such as clothes by irradiating them with microwaves, which are a type of electromagnetic wave. The right direction in Figures 1, 2, and 3 is the front side of the dryer 1. Objects to be dried include scarves, handkerchiefs, towels, and sheets.

[0013] A storage section 3 for accommodating the object to be dried is provided inside the housing 2 of the dryer 1. The storage section 3 is made of metal or the like and has a structure that can suppress the leakage of microwaves irradiated inside to the outside. The inner surface of the storage section 3 is formed to reflect microwaves. The back surface of the storage section 3 is made of perforated metal or the like, which has multiple holes that allow air to pass through but not microwaves.

[0014] A mounting section 4 for placing objects to be dried is provided inside the storage section 3. The mounting section 4 includes a mounting surface for placing the objects to be dried and an outer frame for supporting the mounting surface. The outer frame of the mounting section 4 is supported or suspended by the storage section 3. The mounting surface has multiple holes for air to pass through.

[0015] A door 5 is provided at the front opening of the housing 2 and the storage section 3 to open and close the opening. By opening the door 5, the user can place objects to be dried into the storage section 3 or remove objects to be dried from the storage section 3. The door 5 includes a metal mesh or other structure to suppress the leakage of microwaves to the outside. In addition, a choke structure or the like is formed between the opening and the door 5 to prevent microwaves from leaking through the gap between the opening of the housing 2 and the storage section 3 and the door 5. The storage section 3 and the door 5 constitute a shield to suppress the leakage of microwaves irradiated into the inside of the storage section 3 to the outside.

[0016] Below the housing section 3, a magnetron 6, waveguide 7, antenna 8, antenna housing section 9, partition 10, and motor 11 are provided. The magnetron 6 is an example of a microwave generator, and the antenna 8 is an example of a microwave irradiation unit, and is provided on the bottom surface inside the housing section 3. These components may be provided above or to the side of the housing section 3. The magnetron 6 generates microwaves for drying the object to be dried. The microwaves generated by the magnetron 6 are guided to the antenna 8 via the waveguide 7 and irradiated from the antenna 8 toward the housing section 3. This allows the moisture contained in the object to be dried housed in the housing section 3 to be heated and evaporated. The antenna 8 is rotated by the motor 11. This allows microwaves to be irradiated evenly over the entire area of ​​the housing section 3, so that the object to be dried can be dried evenly and efficiently. The antenna housing section 9 houses the antenna 8.

[0017] A partition plate 10 is provided above the antenna housing 9. The partition plate 10 is made of a microwave-transmitting material such as glass, resin, or ceramic. The contact surface 26 is the contact surface of the antenna 8, as will be described later. In the dryer 1 shown in Figure 2, the antenna 8 is fixed and the motor 11 is not provided.

[0018] The magnetron 6 oscillates electromagnetic waves at a frequency in the 2.45 GHz band, which is allocated as the ISM (Industry Science Medical) band. The magnetron 6 may also oscillate electromagnetic waves at frequencies in the 915 MHz band, which is similarly allocated. In this embodiment, a microwave oscillator such as a magnetron is used as the microwave generation unit. This reduces the manufacturing cost of the dryer 1. The microwave generation unit may also be a semiconductor type microwave oscillator. This allows the oscillation frequency to be varied. It also improves the stability of the output power and oscillation frequency. Furthermore, it improves safety by operating at a low voltage. The magnetron 6 is controlled by a control device described later.

[0019] Above the containment section 3, an outlet 24, an outlet-side air passage 30, an exhaust port 17, a circulation air passage 16, an intake port 18, a heater 22, an inlet-side air passage 29, an inlet 23, and a blower fan 15 are provided. The internal air containing water vapor evaporated from the object to be dried flows out from the outlet 24 located at the front upper part of the containment section 3 into the outlet-side air passage 30, is circulated through the circulation air passage 16 and the inlet-side air passage 29, and is sent into the interior of the containment section 3 by the blower fan 15 through the inlet 23 located at the rear of the containment section 3. Since the circulation air passage 16 is located above the containment section 3, the internal air of the containment section 3, which has become hot, can be circulated efficiently. A portion of the internal air of the containment section 3 is discharged to the outside through the exhaust port 17 located in the outlet-side air passage 30, and outside air is taken in through the intake port 18 located in the inlet-side air passage 29. This allows some of the water vapor contained in the internal air to be discharged to the outside, accelerating the drying of the object to be dried. The heater 22 heats the air flowing into the containment section 3 from the inlet 23. This can accelerate the drying of the object to be dried. The water vapor contained in the internal air may be converted into liquid water by cooling and discharged to the outside. The cooling means for liquefying the water vapor may be air cooling, water cooling, a Peltier element, a heat pump, etc. The cooling means may be provided in any of the outlet side air passage 30, the circulation air passage 16, the inlet side air passage 29, etc., or at any position inside the containment section 3. When liquefying the water vapor and discharging it to the outside, one or more of the exhaust port 17, intake port 18, blower fan 15, and heater 22 may not be provided.

[0020] An electromagnetic wave absorber 12, an absorber housing 13, and a partition plate 14 are provided at the top of the housing section 3. The electromagnetic wave absorber 12 is made of a dielectric or conductive material that absorbs microwaves and converts them into heat. The absorber housing 13 houses the electromagnetic wave absorber 12. The partition plate 14 is provided between the electromagnetic wave absorber 12 and the mounting section 4. The partition plate 14 is made of a microwave-transmitting material such as glass, resin, or ceramic. In this example, the absorber housing 13 also serves as a circulating air passage 16.

[0021] The temperature detection unit 19 detects the temperature of the radio wave absorber 12. The control device estimates the microwave intensity inside the housing unit 3 based on the detection result from the temperature detection unit 19. As will be described later, the dryer 1 of this embodiment is equipped with a microwave intensity detection unit 21, so the temperature detection unit 19 does not need to be provided.

[0022] The temperature detection unit 20 detects the temperature of the air flowing out from the containment unit 3. The control device estimates the amount of moisture contained in the object to be dried based on the detection result from the temperature detection unit 20. As will be described later, the dryer 1 of this embodiment is equipped with a microwave intensity detection unit 21, so the temperature detection unit 20 does not need to be provided. In addition to the temperature detection unit 20, or in place of the temperature detection unit 20, a humidity detection unit may be provided.

[0023] The microwave intensity detection unit 21 detects the microwave intensity inside the housing unit 3. The microwave intensity detection unit 21 includes an absorber that absorbs microwaves and generates heat, and a temperature sensor such as a thermistor that detects the temperature of the absorber. The absorber may be a dielectric loss material such as carbon material, or a magnetic loss material such as iron oxide or an iron-based alloy. The absorber may be a mixture of these materials with resin or rubber. The microwave intensity detection unit 21 may be covered with a cover made of resin or the like.

[0024] The microwave intensity detection unit 21 is not particularly limited in type, and may also be, for example, one that uses an antenna to detect electric field strength or magnetic field strength, or a semiconductor type that rectifies the detected microwaves and converts them into a voltage to measure the intensity.

[0025] The control device estimates the amount of moisture contained in the material to be dried based on the detection results from the microwave intensity detection unit 21. The more moisture contained in the material to be dried, the more microwaves are absorbed by the moisture, thus reducing the microwave intensity. The control device adjusts the microwave output based on the estimated change in moisture content, and stops the microwave output and terminates the drying operation when the rate of change in moisture content falls below a predetermined value. The control device also stops the microwave output when the microwave intensity detected by the microwave intensity detection unit 21 exceeds a threshold. This helps to suppress over-drying of the material to be dried and the generation of sparks, thereby increasing the safety of the dryer 1.

[0026] In order for the control device to properly control the microwave output, the microwave intensity detection unit 21 is required to accurately detect changes in microwave intensity even when the amount of moisture contained in the object to be dried approaches zero and the change in microwave intensity becomes small. Therefore, it is desirable to use a highly sensitive absorber as the absorber, in which the temperature changes sharply in response to changes in microwave intensity. Furthermore, it is desirable to use an absorber with a large temperature change in response to changes in radio wave intensity and a wide dynamic range.

[0027] The microwave intensity detection unit 21 is located inside the housing unit 3, and is positioned such that the absorption of microwaves by the absorber provided by the microwave intensity detection unit 21 does not obstruct the propagation of microwaves in the antenna 8.

[0028] The antenna 8 in this embodiment 1 utilizes a dipole antenna. A dipole antenna is an antenna that radiates microwaves while reflecting them between the antenna and the ground surface. The length of a dipole antenna is an integer multiple of half a microwave wavelength. This is intended to make the tip of the antenna the termination point of the current by matching the wavelength of the microwaves propagating along the antenna with the antenna length. This effect maximizes the resonance amplitude of the electric field at the tip of the antenna, that is, maximizes the intensity of the radiated microwaves.

[0029] Applying this principle, the antenna 8 is designed such that its antenna length, defined by the length from the part connected to the motor 11 to the antenna tip 25, is an integer multiple of half a microwave wavelength, and the intensity of the microwaves radiated from the antenna 8 is maximized at the antenna tip 25.

[0030] If a microwave intensity detection unit 21 equipped with a microwave absorber were located inside the space 27 between the antenna 8 and the ground surface 26, as shown in the shaded area of ​​Figure 2, it would affect the microwaves radiated from the antenna 8, causing a change in their wavelength. As a result, the intensity and direction of the microwaves radiated from the antenna 8 would change, potentially leading to a decrease in microwave intensity or a bias in the microwave distribution. Therefore, in this embodiment 1, the influence on microwaves can be suppressed by installing the microwave intensity detection unit 21 outside the space 27.

[0031] In the dryer 1 of this embodiment shown in Figure 1, the antenna 8 is rotatably mounted, so the space 27 rotates to form a cylinder (shown as a shaded area in Figure 1). The microwave intensity detection unit 21 is located outside this cylindrical space 27. This prevents the absorption of microwaves by the absorber of the microwave intensity detection unit 21 from hindering the propagation of microwaves in the waveguide 7 and antenna 8, thereby stabilizing the impedance matching between the antenna 8 and the magnetron 6 and stabilizing microwave oscillation.

[0032] As shown in Figure 3, the antenna 8 may be installed at an angle to the ground surface 26. In this case as well, the microwave intensity detection unit 21 is located outside the rotating body (shown as a shaded area in Figure 3) formed by rotating the space 27 between the antenna 8 and the ground surface 26.

[0033] For example, the microwave intensity detection unit 21 may be positioned between the mounting surface of the mounting unit 4 and the antenna 8. Microwaves that are not absorbed by the moisture contained in the object to be dried are reflected and overlap inside the housing unit 3, so the microwave intensity at a position far from the object to be dried may not accurately reflect the amount of moisture contained in the object. However, by detecting the microwave intensity at a position close to the object to be dried, the amount of moisture contained in the object to be dried can be estimated more accurately.

[0034] On the other hand, if the microwave intensity detection unit 21 is too close to the antenna 8, it will interfere with the function of the antenna 8. Conversely, if the microwave intensity detection unit 21 is too far from the antenna 8, for example, if it is installed near the radio wave absorber 12 in Figure 1, the microwaves will be reflected and overlapped inside the housing unit 3 before reaching the microwave intensity detection unit 21, so the microwave intensity may not accurately reflect the amount of moisture contained in the object being dried. Also, if the microwave intensity detection unit 21 is installed near the object being dried, the microwaves will be absorbed by the moisture in the object being dried, resulting in a large change in their intensity. Taking these factors into consideration, it is preferable to position the microwave intensity detection unit 21 between the object being dried and the antenna 8.

[0035] For example, by positioning the microwave intensity detection unit 21 between the mounting surface of the mounting unit 4 and the antenna 8, the amount of moisture contained in the object to be dried can be estimated more accurately. In particular, the microwave intensity detection unit 21 may be positioned near the mounting unit 4, between the mounting surface of the mounting unit 4 and the partition 10. This position is suitable because it is close to the object to be dried but not too close to the antenna 8. Alternatively, the microwave intensity detection unit 21 may be installed at the edge (outer edge) inside the housing unit 3. This shortens the output line from the microwave intensity detection unit 21 to the control device 40 described later, which is located inside the housing unit 3. As a result, electromagnetic noise that microwaves impose on the output line of the microwave intensity detection unit 21 can be reduced, enabling the microwave intensity detection unit 21 to detect more accurately.

[0036] Furthermore, the microwave power detection device described in Patent Document 1 is installed at a distance from the object being heated, and therefore cannot accurately detect the amount of moisture contained in the object being heated. In fact, the invention described in Patent Document 1 relates to a microwave oven, and the problem of accurately detecting the amount of moisture contained in the object being heated was not considered.

[0037] The microwave intensity detection unit 21 is positioned so that when microwaves are irradiated from the antenna 8 under predetermined conditions, the temperature of the absorber contained in the microwave intensity detection unit 21 rises above a predetermined temperature. These predetermined conditions may, for example, be that no object to be dried is contained inside the containment unit 3. The predetermined temperature may, for example, be the average value when the microwave intensity detection unit 21 is placed at multiple positions in the containment unit 3. That is, the microwave intensity detection unit 21 is positioned so that when microwaves are irradiated from the antenna 8 when no object to be dried is contained in the containment unit 3, the microwave intensity is higher than the average value of the microwave intensity in the containment unit 3. Inside the containment unit 3, standing waves are generated by the reflection of microwaves from the inner surface of the containment unit 3. The microwave intensity detection unit 21 may be positioned near the antinodes of these standing waves. This allows for a wider dynamic range of temperature detected by the microwave intensity detection unit 21, thereby improving detection accuracy.

[0038] Multiple microwave intensity detection units 21 are provided at the same height. This allows for the detection of microwave intensity that more accurately reflects the amount of moisture contained in the object to be dried. Even if the object to be dried is stored unevenly or drying is uneven, variations in the detection results of the multiple microwave intensity detection units 21 will occur, allowing for the recognition of the presence of moisture imbalances. This enables optimal control of the irradiation output and accurate determination of the drying state. This suppresses false detections due to uneven storage positions of the object to be dried and suppresses the deterioration of accuracy due to uneven drying. Multiple microwave intensity detection units 21 are provided, for example, at the four corners of the mounting section 4. Alternatively, the microwave intensity detection units 21 may be provided inside the storage section 3, not limited to the mounting section 4.

[0039] Figure 4 shows the microwave flow in the dryer 1. (1) Microwaves are generated from the magnetron 6. (2) The generated microwaves flow into the waveguide 7. (3) The microwaves that flow into the waveguide 7 are irradiated into the inside of the containment section 3 via the antenna 8. (4) The microwaves irradiated into the inside of the containment section 3 are diffusely reflected inside the containment section 3 and absorbed by the moisture contained in the material being dried. (5) Some of the microwaves that are not absorbed are absorbed by the radio wave absorber 12, and the rest return to the magnetron 6 and are absorbed.

[0040] Figure 5 shows an example of an object to be dried. This figure is a schematic view of the inside of the storage section 3 from above. A long-sleeved shirt is placed in the storage section 4 in a folded state.

[0041] Figure 6 shows an example of an object being dried during the drying process. The top part of a folded long-sleeved shirt is difficult to dry because the sleeves are folded, which means it contains a lot of moisture, and the moisture does not evaporate easily. The bottom part of a folded long-sleeved shirt dries easily because it contains less moisture, and the moisture evaporates easily. In cases where drying is uneven like this, if the completion of drying is determined based on the total amount of moisture in the long-sleeved shirt, the bottom part of the shirt may become excessively dry and damaged. If drying is completed too early to prevent damage to the object being dried, the top part of the long-sleeved shirt may remain damp.

[0042] As shown in Figures 5 and 6, four microwave intensity detection units 21a to 21d are provided as microwave intensity detection units 21, each located on the inner surface of the housing units 3 at the four corners below the mounting unit 4. This allows for the detection of microwave intensity at each of the four corners of the mounting unit 4, and the estimation of the moisture content distribution at each location. Therefore, even if uneven drying occurs, microwave irradiation can be appropriately controlled. Consequently, drying efficiency can be improved while preventing damage to the object being dried and the generation of sparks.

[0043] Incidentally, as a suitable position where the microwave intensity detection unit 21 can detect efficiently in this way, it includes the inner surface of the housing unit 3, above the placement unit 4, and near the upper end of the object to be dried. It does not necessarily have to be at the four corners. That is, the microwave intensity detection unit 21 is preferably provided on the inner surface of the housing unit 3 near the lower and upper sides of the placement unit 4.

[0044] Also, as described above, by providing a plurality of microwave intensity detection units 21 at the same height position, it is possible to suppress false detection due to deviation of the storage position of the object to be dried and to suppress deterioration of accuracy due to uneven drying. In addition to this, when the microwave radiation unit is centered in a top view, for example, when the antenna 8 rotates, the microwave intensity detection units 21 are preferably provided at a plurality of positions that are point-symmetric or line-symmetric about the rotation axis in a top view at the same height position. Thereby, even if the object to be dried is stored unevenly or uneven drying occurs, variations occur in the detection results of the plurality of microwave intensity detection units 21, and the presence of moisture unevenness can be recognized more accurately. As a result, the control of the irradiation output can be optimally controlled and the drying state can be accurately determined, so that false detection due to deviation of the storage position of the object to be dried can be suppressed and deterioration of accuracy due to uneven drying can be suppressed.

[0045] Two, six, eight, or more microwave intensity detection units 21 may be provided. The microwave intensity detection unit 21 may be further provided at the center of gravity position of the placement unit 4.

[0046] FIG. 7 shows the functional configuration of the control device 40 provided in the dryer 1 of the first embodiment. The control device 40 is realized by hardware such as a microcomputer, a microcontroller, or an integrated circuit.

[0047] The control device 40 includes a detection result acquisition unit 41, a moisture content estimation unit 42, a drying operation control unit 43, a magnetron control unit 44, and an antenna control unit 45. These components are realized hardware-wise by any circuit, a computer's CPU (Central Processing Unit), memory, other LSIs (Large Scale Integrated Circuits), etc., and software-wise by a program loaded into the memory, etc. Here, however, functional blocks realized by their cooperation are depicted. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms such as only by hardware or in combination with hardware and software.

[0048] The detection result acquisition unit 41 acquires the detection result from the microwave intensity detection unit 21. The detection result acquisition unit 41 may acquire the intensity of the microwave detected by the microwave intensity detection unit 21, or may acquire the temperature of the absorber detected by the temperature sensor of the microwave intensity detection unit 21 and calculate the intensity of the microwave based on the acquired temperature of the absorber.

[0049] The moisture content estimation unit 42 estimates the moisture content contained in the drying object based on the detection result acquired by the detection result acquisition unit 41. The moisture content estimation unit 42 may estimate the moisture content using a table or relational expression showing the correspondence between the detection result and the moisture content determined in advance by experiments, etc., or an artificial intelligence learned in advance, etc.

[0050] The drying operation control unit 43 controls the drying operation in the dryer 1. The drying operation control unit 43 controls each component provided in the dryer 1 in order to execute the drying operation according to the instruction received from the user.

[0051] The magnetron control unit 44 controls the magnetron 6 based on the instruction from the drying operation control unit 43.

[0052] The antenna control unit 45 controls the rotation speed, rotation direction, rotation angle, phase, length, orientation, etc. of the antenna 8 based on the instruction from the drying operation control unit 43.

[0053] The drying operation control unit 43 controls the microwave irradiation intensity, irradiation area, irradiation time, etc., of the microwaves irradiated by the antenna 8 based on the detection results obtained by the multiple microwave intensity detection units 21 acquired by the detection result acquisition unit 41. The drying operation control unit 43 may also control the microwave irradiation intensity, irradiation area, irradiation time, etc., based on the average value of the detection results of the multiple microwave intensity detection units 21. The drying operation control unit 43 may lower the microwave irradiation intensity or stop microwave irradiation if the average value of the detection results of the multiple microwave intensity detection units 21 exceeds a predetermined threshold. The drying operation control unit 43 may lower the microwave irradiation intensity or stop microwave irradiation if any of the detection results of the multiple microwave intensity detection units 21 exceed a predetermined threshold. The drying operation control unit 43 may lower the microwave irradiation intensity or stop microwave irradiation if all of the detection results of the multiple microwave intensity detection units 21 exceed a predetermined threshold.

[0054] The drying operation control unit 43 may lower the threshold value if the object to be dried, which contains metal such as a fastener or a communication device such as an RFID (Radio Frequency Identification) tag, is stored in the storage unit 3. The dryer 1 may determine the presence or absence of metal or a communication device by communicating with the communication device, such as an RFID tag, attached to the object to be dried. In this case, the dryer 1 is equipped with a communication device for communicating with the communication device, such as an RFID tag.

[0055] The drying operation control unit 43 may estimate the distribution of moisture content in the object to be dried based on the detection results of the multiple microwave intensity detection units 21a, 21b, 21c, and 21d, and control the irradiation intensity, irradiation area, and irradiation time of the microwaves irradiated from the antenna 8 so that the distribution of moisture content is averaged. More specifically, the drying operation control unit 43 may control the microwave irradiation amount to be higher in areas with high moisture content than in areas with low moisture content. This suppresses uneven drying and allows the object to be dried evenly. It also improves drying efficiency. The microwave irradiation amount is expressed as the product of the microwave irradiation intensity and the irradiation time.

[0056] The drying operation control unit 43 may increase the intensity of microwaves irradiated from the magnetron 6 when the antenna 8 is in a region with a high moisture content, and decrease the intensity of microwaves when the antenna 8 is in a region with a low moisture content. The drying operation control unit 43 may keep the output of the magnetron 6 constant, slow down the rotation speed of the antenna 8 when the antenna 8 is in a region with a high moisture content, and speed up the rotation speed of the antenna 8 when the antenna 8 is in a region with a low moisture content. The drying operation control unit 43 may also cause the antenna 8 to reciprocate in a region with a high moisture content.

[0057] If multiple antennas 8 are provided, the drying operation control unit 43 may control the phase of the microwaves irradiated from the antennas 8 so that standing waves are generated in areas with a high moisture content.

[0058] [1-2. Operation] The operation and function of the dryer 1 configured as described above will be explained below.

[0059] Figure 8 is a flowchart showing the procedure for the drying operation. The drying operation control unit 43 of the control device 40 causes the magnetron control unit 44 to control the magnetron 6 to irradiate the inside of the housing 3 with microwaves (S32). The drying operation control unit 43 causes the antenna control unit 45 to control the motor 11 to rotate the antenna 8 (S34). The drying operation control unit 43 turns on the heater 22 to heat the air flowing into the inside of the housing 3 (S36). The drying operation control unit 43 drives the blower fan 15 to allow air to flow into the inside of the housing 3 (S37).

[0060] The detection result acquisition unit 41 acquires the detection results from a plurality of microwave intensity detection units 21a, 21b, 21c, and 21d (S38). The moisture content estimation unit 42 estimates the distribution of moisture content contained in the object to be dried based on the detection results (S40). The moisture content estimation unit 42 may further acquire images captured by an infrared camera or the like to estimate the distribution of moisture content contained in the object to be dried. The drying operation control unit 43 adjusts the microwave irradiation pattern (S44).

[0061] The drying operation control unit 43 may control the magnetron 6 or antenna 8 based on the sum of the detection results from the multiple microwave intensity detection units 21a, 21b, 21c, and 21d. For example, if the sum of the detection results is large, the drying operation control unit 43 may estimate that the object to be dried contains a large amount of moisture, and therefore may increase the intensity of the microwaves irradiated from the antenna 8 compared to when the sum of the detection results is small.

[0062] The drying operation control unit 43 may control the magnetron 6 or antenna 8 based on the difference in detection results from the multiple microwave intensity detection units 21a, 21b, 21c, and 21d. For example, if the difference in detection results from the two microwave intensity detection units 21 is large, the drying operation control unit 43 may estimate that uneven drying has occurred in the object to be dried, and therefore may control the microwave irradiation amount to be higher in areas with high moisture content than in areas with low moisture content.

[0063] The drying operation control unit 43 may control the magnetron 6 or antenna 8 based on the time change of the detection results of the multiple microwave intensity detection units 21a, 21b, 21c, and 21d. For example, if the time change of the detection result is small, the drying operation control unit 43 estimates that the amount of moisture contained in the object to be dried has decreased, so it may lower the intensity of the microwaves irradiated from the antenna 8 compared to when the time change of the detection result is large.

[0064] The drying operation control unit 43 returns to S32 and continues the drying operation until the rate of change of moisture content falls below a predetermined value (N in S46). When the rate of change of moisture content falls below a predetermined value (Y in S46), the drying operation control unit 43 stops the oscillation of microwaves by the magnetron 6 (S48), stops the rotation of the antenna 8 (S50), stops the heater 22 (S52), stops the blower fan 15 (S54), and ends the drying operation.

[0065] [1-3. Effects, etc.] As described above, in this embodiment, the dryer 1 comprises a storage section 3 for storing the object to be dried, a mounting section 4 for placing the object to be dried inside the storage section 3 and having a plurality of holes for air to pass through, an antenna 8 (microwave irradiation section) for irradiating microwaves into the inside of the storage section 3, a microwave intensity detection section 21 for detecting the microwave intensity by detecting the temperature of an absorber that absorbs microwaves and generates heat, and a control device 40 having a moisture content estimation section 42 for estimating the amount of moisture contained in the object to be dried based on the detection result of the microwave intensity detection section 21. The microwave intensity detection section 21 is provided on the inner surface of the storage section 3 near the mounting section 4, and the control device 40 is configured to adjust the microwave output based on the estimated change in moisture content. As a result, the amount of moisture contained in the object to be dried can be accurately estimated, so the operation of the dryer 1 can be appropriately controlled, drying unevenness can be suppressed and drying efficiency can be improved. In addition, over-drying of the object to be dried and the generation of sparks can be suppressed, and the safety of the dryer 1 can be enhanced.

[0066] Furthermore, in this embodiment, the dryer 1 may have an antenna 8 (microwave irradiation unit) provided on the bottom surface of the housing unit 3, and the microwave intensity detection unit 21 may be provided at a position between the mounting unit 4 and the antenna 8. This makes it possible to detect the microwave intensity that more accurately reflects the amount of moisture contained in the object to be dried.

[0067] Furthermore, in this embodiment, the dryer 1 may be equipped with multiple microwave intensity detection units 21, which may be distributed at the same height. This allows for the detection of microwave intensity that more accurately reflects the amount of moisture contained in the object to be dried, enabling the recognition of variations in detection results and the presence of uneven moisture distribution, thereby allowing for optimal control of the irradiation output and accurate determination of the drying state.

[0068] Furthermore, in this embodiment, the dryer 1 may have multiple microwave intensity detection units 21 positioned symmetrically in points or lines with respect to the microwave radiation unit when viewed from above. This allows for greater accuracy in recognizing the presence of moisture imbalances, even if the objects to be dried are unevenly stored or drying is inconsistent, as variations will occur in the detection results of the multiple microwave intensity detection units 21.

[0069] Furthermore, in this embodiment, the dryer 1 may be provided with a plurality of microwave intensity detection units 21, and the control device 40 may be configured to adjust the microwave output based on the average value of the detection results from the plurality of microwave intensity detection units 21a to 21d. This allows for more appropriate control of the operation of the dryer 1 by lowering the microwave irradiation intensity or stopping microwave irradiation when the average value exceeds a predetermined threshold.

[0070] Furthermore, in this embodiment, the dryer 1 may be configured such that the control device 40 has a predetermined threshold for the electric field strength detected by the microwave intensity detection unit 21, and adjusts the microwave output so that it is below this threshold. This allows for more appropriate control of the operation of the dryer 1 by lowering the microwave irradiation intensity or stopping microwave irradiation when the threshold is exceeded. In addition, it is possible to suppress over-drying of the material being dried and the generation of sparks, thereby improving the safety of the dryer 1.

[0071] Furthermore, in this embodiment, the dryer 1 may be provided with multiple microwave intensity detection units 21, and the control device 40 may be configured to estimate the distribution of moisture content in the object to be dried based on the results from the moisture content estimation unit 42, and to adjust the microwave output so that the distribution of moisture content is averaged. This can improve drying efficiency and suppress uneven drying.

[0072] Furthermore, in this embodiment, the dryer 1 is composed of a rotating antenna 8 that irradiates microwaves, and the control device 40 may be configured to increase the intensity of the irradiated microwaves when the antenna 8 is in an area with a high moisture content, and to decrease the intensity of the irradiated microwaves when the antenna 8 is in an area with a low moisture content. This improves drying efficiency and reduces uneven drying.

[0073] Furthermore, in this embodiment, the dryer 1 is composed of an antenna 8 with a rotating microwave irradiation unit, and the control device 40 may be configured to keep the intensity of the microwaves irradiated from the antenna constant, slow down the rotation speed of the antenna 8 when the antenna 8 is in an area with a high moisture content, and speed up the rotation speed of the antenna 8 when the antenna 8 is in an area with a low moisture content. This improves drying efficiency and reduces uneven drying.

[0074] (Other Embodiments) As described above, Embodiment 1 has been explained as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this and can be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, it is possible to create new embodiments by combining the components described in Embodiment 1 above.

[0075] Therefore, other embodiments are illustrated below.

[0076] In Embodiment 1, the radio wave absorber 12 and the absorber housing 13 are provided at the top of the housing 3, but the invention is not limited to this. For example, the radio wave absorber 21 may be provided at the bottom of the housing 3, between the partition plate 10 and the mounting section 4, or on the lower surface of the partition plate 10, in the antenna housing 9. With these configurations, it is preferable that air flows between the partition plate 10 and the mounting section 4, and the radio wave absorber 21 is provided along the airflow to exchange heat. When the radio wave absorber 12 is arranged in this manner, even if the intensity of microwaves irradiated from the antenna 8 is relatively high, the intensity of microwaves irradiated onto the object to be dried is reduced, the generation of sparks is suppressed, and damage to the object to be dried is suppressed. In addition, the radio wave absorber 12 can heat the air in the housing 3 to improve drying efficiency.

[0077] In Embodiment 1, a dryer 1 was described as an example of a dryer, which dries an object placed on it. The dryer may be a drum-type dryer, a non-drum type dryer, a washer-dryer, etc. The object to be dried may not be clothing.

[0078] In Embodiment 1, the case in which the antenna 8 is rotatably mounted was described, but the antenna 8 may be fixed. In this case, the mounting part 4 may be rotatably mounted. Furthermore, the microwave irradiation part was described as an antenna 8 that radiates microwaves while reflecting them between the antenna and the ground surface, but it is not limited to this, and any device that irradiates microwaves into the interior of the housing part 3 from a magnetron 6 or waveguide 7 may suffice.

[0079] This disclosure is applicable to dryers.

[0080] 1...Dryer 2...Housing 3...Housing section 4...Mounting section 5...Door 6...Magnetron 7...Waveguide 8...Antenna 9...Antenna housing section 10...Partition plate 11...Motor 12...Radio wave absorber 13...Absorber housing section 14...Partition plate 15...Blower fan 16...Circulation air passage 17...Exhaust port 18...Intake port 19...Temperature detection unit 20...Temperature detection unit 21...Microwave intensity detection unit 22...Heater 23...Inlet 24...Outlet 25...Antenna tip 26...Grounding surface 27...Space 29...Inlet side air passage 30...Outlet side air passage 40...Control device 41...Detection result acquisition unit 42...Moisture content estimation unit 43...Drying operation control unit 44...Magnetron control unit 45...Antenna control unit

Claims

1. A dryer comprising: a storage section for containing an object to be dried; a placement section inside the storage section on which the object to be dried is placed and which has a plurality of holes for air to pass through; a microwave irradiation section for irradiating the inside of the storage section with microwaves; a circulation air passage for causing the internal air containing water vapor evaporated by the microwaves heating the object to be dried to flow out of the storage section, discharge the moisture, and then allow it to flow back in; a microwave intensity detection section for detecting the intensity of the microwaves; and a control device having a moisture content estimation section for estimating the amount of moisture contained in the object to be dried based on the detection result of the microwave intensity detection section, wherein the microwave intensity detection section is provided on the inner surface of the storage section near the placement section, and the control device is configured to adjust the output of the microwaves based on the estimated change in the amount of moisture.

2. The dryer according to claim 1, wherein the microwave irradiation unit is provided on the bottom surface of the housing unit, and the microwave intensity detection unit is provided at a position between the housing unit and the microwave irradiation unit.

3. The dryer according to claim 1, wherein a plurality of microwave intensity detection units are provided and are distributed at the same height.

4. The dryer according to claim 3, wherein the plurality of microwave intensity detection units are arranged in point-symmetric or line-symmetric positions with respect to the microwave radiation unit when viewed from above.

5. The dryer according to claim 1, wherein a plurality of microwave intensity detection units are provided, and the control device is configured to adjust the microwave output based on the average value of the detection results from the plurality of microwave intensity detection units.

6. The dryer according to any one of claims 1 to 5, wherein the control device has a predetermined threshold for the electric field strength detected by the microwave intensity detection unit, and is configured to adjust the microwave output so that the microwave irradiation intensity is less than or equal to the threshold when at least one of the detection results of the microwave intensity detection unit exceeds the predetermined threshold.

7. The dryer according to claim 1, wherein a plurality of microwave intensity detection units are provided, and the control device is configured to estimate the distribution of the amount of moisture contained in the object to be dried based on the results of the moisture content estimation unit, and to adjust the output of the microwaves so that the distribution of the amount of moisture is averaged.

8. The dryer according to claim 7, wherein the microwave irradiation unit is composed of a rotating antenna, and the control device is configured to increase the intensity of the microwaves irradiated when the antenna is in a region with a high moisture content, and to decrease the intensity of the microwaves irradiated when the antenna is in a region with a low moisture content.

9. The dryer according to claim 7, wherein the microwave irradiation unit is composed of a rotating antenna, and the control device is configured to keep the intensity of the microwaves irradiated from the antenna constant, to slow down the rotation speed of the antenna when the antenna is in a region with a high moisture content, and to speed up the rotation speed of the antenna when the antenna is in a region with a low moisture content.

Images