The present invention relates to a refrigerator that uses electromagnetic waves to heat a stored object.
In recent years, there has been a growing need for thawing stored objects such as foodstuff kept frozen and frozen food in a short time in refrigerators. PTL 1 discloses a refrigerator including a heating chamber that uses microwaves to heat a stored object.
Further, PTL 2 discloses a high frequency heater that thaws a stored object using high frequency waves in a HF to VHF band instead of microwaves. Unlike microwaves, the high frequency waves in the HF to VHF band have high rectilinearity, and form an electric field between two electrodes to heat the stored object.
When a stored object is heated using electromagnetic waves, it is necessary to take measures to prevent the electromagnetic waves from leaking outside. In order to prevent the electromagnetic waves from leaking to outside, it is common to provide an electromagnetic wave shield and ground the electromagnetic wave shield. However, it is difficult to ground the electromagnetic wave shield provided on a door that moves in a front and rear direction, such as a refrigerator door. This is because wiring that runs between the electromagnetic wave shield provided on the door of the refrigerator and a grounding part may be disconnected because of being repeatedly bent and extended due to opening and closing of the door.
An object of the present invention is therefore to provide a structure capable of exhibiting a function as an electromagnetic wave shield even for a refrigerator door in which wiring to the grounding part is difficult.
In order to solve the above-mentioned problem, the refrigerator provided by the present invention includes at least one storage chamber, in which the refrigerator heats a stored object inside the storage chamber using an electromagnetic wave, the storage chamber includes a door provided with a first electromagnetic wave shield, and the refrigerator includes a housing part provided with a second electromagnetic wave shield, the housing part being in contact with the door while the door is closed.
The present invention makes it possible to provide a structure capable of exhibiting a function as an electromagnetic wave shield even for a refrigerator door in which wiring to a grounding part is difficult.
Exemplary embodiments of the present invention will be described below with reference to the drawings. Note that the following exemplary embodiments do not limit the invention according to the claims, and all combinations of the characteristics described in the exemplary embodiments are not necessarily essential to the means for solving the invention.
Refrigerator 100 includes a plurality of storage compartments. Refrigerating compartment 103 is provided at a top of refrigerator 100. Ice-making compartment 104 and thawing compartment 105 are provided below refrigerating compartment 103. Further, freezing compartment 106 is provided below ice-making compartment 104 and thawing compartment 105. Vegetable compartment 107 is provided at a bottom of refrigerator 100.
Refrigerating compartment 103 is maintained at a temperature that does not freeze for refrigerating storage, specifically, in a temperature range from 1° C. to 5° C. Vegetable compartment 107 is maintained at a temperature range from 2° C. to 7° C., which is equivalent to or slightly higher than a temperature in refrigerating compartment 103. Freezing compartment 106 is set in a freezing temperature range, specifically from −22° C. to −15° C., for frozen storage. Thawing compartment 105 is normally maintained in the same freezing temperature range as freezing compartment 106, and performs a heating treatment for thawing a stored object in response to a user's heating instruction. A structure of thawing compartment 105 and specific contents of the heat treatment will be described later in detail.
Machine compartment 108 is provided at an upper part of refrigerator 100. Machine compartment 108 accommodates components such as compressor 109 and a dryer that removes water, which configure a refrigeration cycle. Machine compartment 108 may be provided at a lower part of refrigerator 100.
Cooling compartment 110 is provided behind freezing compartment 106 and vegetable compartment 107. Cooling compartment 110 accommodates cooler 111 that generates cool air and cooling fan 112 that blows the cool air generated by cooler 111 to each storage compartment. Defrosting heater 113 that defrosts frost and ice adhering to cooler 111 and surroundings thereof is provided below cooling compartment 110. Drain pan 114, drain tube 115, and evaporating dish 116 are provided below defrosting heater 113.
Next, a configuration of thawing compartment 105 will be described with reference to
Next, a mechanism of heating and thawing the stored object kept frozen in thawing compartment 105 will be described. Refrigerator 100 includes oscillator 206, matching unit 207, oscillation electrode 208, and counter electrode 209. Oscillator 206 is embedded in the heat insulating material on the rear side of refrigerator 100. Matching unit 207 adjusts a load impedance formed by oscillation electrode 208, counter electrode 209, and the stored object to be close to an output impedance of oscillator 206. Matching unit 207 is provided in air passage 201 and is covered with the heat insulating material. Oscillation electrode 208 is embedded in a heat insulating partition wall that configures the top surface of thawing compartment 105. Counter electrode 209 is embedded in a heat insulating partition wall configuring the bottom surface of thawing compartment 105. Matching unit 207 is connected to oscillation electrode 208. Oscillator 206 is connected to matching unit 207. A length of wiring connecting oscillator 206, matching unit 207, and oscillation electrode 208 is desirably as short as possible, and thus these are concentrated near thawing compartment 105. Oscillator 206 outputs a high frequency wave in the VHF band (40 MHz in the present exemplary embodiment). Then, an electric field is formed between oscillation electrode 208 and counter electrode 209. As a result, the stored object placed between oscillation electrode 208 and counter electrode 209 is heated.
Refrigerator 100 is provided with an electromagnetic wave shield that prevents electromagnetic waves from leaking to outside. Electromagnetic wave shield 210 is embedded in above air passage 201 (in other words, a partition that separates thawing compartment 105 and refrigerating compartment 103). An electromagnetic wave shield 213 is embedded inside door 212 that opens and closes thawing compartment 105. Electromagnetic wave shield 213 is covered with the heat insulating material. Electromagnetic wave shield 211 and electromagnetic wave shield 214 are embedded in a housing part of refrigerator 100 which is in contact with door 212 while door 212 is closed. Electromagnetic wave shield 215 is provided on a wall surface of a space that accommodates oscillator 206. Further, electromagnetic wave shield 216 is provided on a wall surface of the rear side of thawing compartment 105. When a steel plate is used as an exterior material of a housing of refrigerator 100, the steel plate itself has a role of an electromagnetic wave shield.
Electromagnetic wave shield 213 provided inside door 212 will be described in more detail. When wiring runs between electromagnetic wave shield 213 and a grounding part of refrigerator 100, because the user opens and closes door 212, the wiring is repeatedly bent and extended and metal fatigue accumulates as door 212 is opened and closed. This causes a disconnection of the wiring, which is not preferable to ground electromagnetic wave shield 213 with the wiring. Therefore, in the present exemplary embodiment, a distance between electromagnetic wave shield 213 and electromagnetic wave shield 211 when door 212 is closed, and a distance between electromagnetic wave shield 213 and electromagnetic wave shield 214 when door 212 is closed are set shorter than one quarter of a wavelength of each electromagnetic wave. For example, the distance between electromagnetic wave shield 213 and electromagnetic wave shield 211 when door 212 is closed and the distance between electromagnetic wave shield 213 and electromagnetic wave shield 214 when door 212 is closed are within 30 mm. Electromagnetic wave shield 211 and electromagnetic wave shield 214 are grounded, and thus, by bringing electromagnetic wave shield 213 close to electromagnetic wave shield 211 and electromagnetic wave shield 214 while door 212 is closed, an effect equal to that of grounding by wiring can be obtained. Further, an end of electromagnetic wave shield 213 is bent inside refrigerator 100, and thus electromagnetic wave shield 213 can be easily brought close to electromagnetic wave shield 211 and electromagnetic wave shield 214. Electromagnetic wave shield 216 is provided on a wall surface of the rear side of thawing compartment 105. This aims to prevent the electric field generated between oscillation electrode 208 and counter electrode 209 and a high frequency noise generated from matching unit 207 from affecting electric components such as cooling fan 112 and damper 203.
Electromagnetic wave shield 210 may be provided inside refrigerating compartment 103 located above thawing compartment 105. Refrigerating compartment 103 is often provided with a partial freezing compartment or a chilling compartment, and a top surface of the partial freezing compartment or the chilling compartment may be used as an electromagnetic wave shield.
Air passage 201 has a shape that bends at a substantially right angle. A distance between area A corresponding to this bent part and matching unit 207, and a width of air passage 201 are set shorter than one quarter of the wavelength of the electromagnetic wave, and thus the high frequency noise generated from matching unit 207 cannot curve at area A. For example, the distance between area A and matching unit 207 is within 30 mm.
When the user opens and closes door 212, high-humidity air flows into thawing compartment 105 in the freezing temperature range, and dew condensation easily occurs inside thawing compartment 105. When oscillation electrode 208 and counter electrode 209 are exposed inside thawing compartment 105, dew condensation occurs on surfaces of oscillation electrode 208 and counter electrode 209, making a formation of the electric field unstable. As a result, a case may occur in which a heating action is not sufficiently obtained or not obtained at all. On the other hand, in the present exemplary embodiment, both oscillation electrode 208 and counter electrode 209 are embedded in the partition wall configuring thawing compartment 105. This can prevent dew condensation from occurring on the surfaces of oscillation electrode 208 and counter electrode 209.
Further, oscillator 206 and matching unit 207 are not installed inside thawing compartment 105, and thus dew condensation can be prevented from occurring on oscillation unit 206 and matching unit 207. Particularly, in the present exemplary embodiment, matching unit 207 is installed in air passage 201. The cool air with low humidity flowing through air passage 201 can prevent dew condensation from occurring on matching unit 207. Further, oscillator 206 is embedded in the heat insulating material on the rear side of refrigerator 100 and is independent of thawing compartment 105, and thus dew condensation is prevented from occurring on oscillator 206. Both oscillator 206 and matching unit 207 may be installed in air passage 201, or both oscillator 206 and matching unit 207 may be embedded in the heat insulating material on the rear side of refrigerator 100.
Next, a positional relationship between oscillation electrode 208 and ventilation ports 202 will be described with reference to
Next, with reference to
Next, electromagnetic wave shield 210 and a positional relationship between electromagnetic wave shield 210 and electrode hole 301 will be described with reference to
Further, when electromagnetic wave shield 210 has a flat plate-like structure without holes, the area where oscillation electrode 208 and electromagnetic wave shield 210 face each other becomes larger than when electromagnetic wave shield 210 has a mesh structure. This increases the degree of energy loss described above. Thus, making electromagnetic wave shield 210 into a mesh structure leads to reducing the degree of energy loss.
Shapes of electrode holes 301 and electrode holes 302 are not limited to a circle, but may be a rectangle or an ellipse. In this case, the shapes of ventilation port 202 and ventilation port 204 also need to match the shapes of electrode holes 301 and 302, respectively.
Next,
Door opening detection switch 217 is a switch that detects whether door 212 is open or closed. Door opening detection switch 217 is a push-in switch, and when door opening detection switch 217 is pushed in, door opening detection switch 217 outputs to controller 601 that the door 212 is closed. On the other hand, when door opening detection switch 217 is not pushed in, door opening detection switch 217 outputs to controller 601 that door 212 is open. Temperature sensor 218 detects a temperature of thawing compartment 105. Door opening detection switch 217 and temperature sensor 218 are provided at positions shown in
Next, the process executed by refrigerator 100 when refrigerator 100 receives an instruction to execute the heat treatment from the user will be described with reference to a flowchart in
First, in step 701, controller 601 receives the instruction to execute the heat treatment from the user. The execution instruction is input to refrigerator 100 in one of the following three patterns.
(Pattern 1) Refrigerator 100 includes an operation unit (not shown). The user operates this operation unit to input the execution instruction to refrigerator 100.
(Pattern 2) Refrigerator 100 includes a wireless communication unit (not shown), and this wireless communication unit is connected to a wireless LAN network. When the user inputs a heating instruction to an external terminal such as a smartphone, the wireless communication unit receives the execution instruction via the wireless LAN network, and the execution instruction is input to refrigerator 100.
(Pattern 3) Refrigerator 100 includes a voice recognition unit (not shown), and the user inputs the execution instruction to refrigerator 100 by voice.
Next, in step 702, controller 601 determines whether door 212 is closed. Controller 601 determines whether door 212 is closed based on an output result of door opening detection switch 217. When door 212 is closed, the processing proceeds to step 703. On the other hand, when the door is open, the processing proceeds to step 704.
Next, step 703 will be described. In step 703, controller 601 starts outputting electromagnetic waves in order to heat the stored object in thawing compartment 105. Oscillator 206 outputs electromagnetic waves under control of controller 601, and thus an electric field is formed between oscillation electrode 208 and counter electrode 209, and heating of a storage unit is started.
Next, step 704 will be described. In step 704, controller 601 notifies an error without starting the output of the electromagnetic waves. There is a risk that electromagnetic waves may leak outside refrigerator 100 because door 212 is open. Thus, in step 704, the output of the electromagnetic waves is not started to prevent the electromagnetic waves from leaking out of refrigerator 100. The error notification executed by controller 601 refers to displaying a message such as “The door is open. Please close the door and try again” on a display unit (not shown) of refrigerator 100 or outputting a similar message by voice. With such a notification of error, controller 601 prompts the user to close door 212.
Next, the process executed by refrigerator 100 after starting the output of electromagnetic waves will be described with reference to the flowchart in
First, in step 801, controller 601 determines whether there is a stored object to be heated. Controller 601 operates matching unit 207 to execute a matching process for minimizing a reflected wave of the electromagnetic wave. When a ratio of the reflected wave to the output electromagnetic wave (hereinafter this ratio is called reflectance) exceeds threshold value R1 immediately after the matching process is completed, controller 601 determines that there is no stored object to be heated in thawing compartment case 401, and the processing proceeds to step 802. On the other hand, when the reflectance immediately after the completion of the matching process does not exceed predetermined value R1, controller 601 determines that there is a stored object to be heated in thawing compartment case 401, and the processing proceeds to step 803.
Next, step 802 will be described. In step 802, controller 601 ends the output of the electromagnetic waves. At this time, controller 601 may display a message such as “The food is not stored in the thawing compartment, and thawing is completed” on the display unit (not shown) of refrigerator 100, or output a similar message by voice.
Next, step 803 will be described. In step 803, controller 601 determines whether door 212 is open. When door 212 is not open, that is, when door 212 remains closed, the processing proceeds to step 804. On the other hand, when door 212 is open, the processing proceeds to step 806.
Next, step 806 will be described. In step 806, controller 601 stops the output of the electromagnetic waves. When the electromagnetic waves are continuously output with door 212 open, the electromagnetic waves may leak to the outside of refrigerator 100. Thus, in step 806, the output of the electromagnetic waves is stopped to prevent the electromagnetic waves from leaking out of refrigerator 100. At this time, controller 601 may display a message such as “Thawing is stopped. Please close the door to restart thawing” on the display unit (not shown) of refrigerator 100, or may output a similar message by voice.
Next, in step 807, controller 601 determines whether door 212 is closed. When door 212 is closed, the processing proceeds to step 808. On the other hand, when door 212 is not closed, that is, when door 212 remains open, controller 601 stands by until door 212 is closed.
Next, in step 808, controller 601 restarts the output of the electromagnetic waves. When the output of electromagnetic waves is restarted, the process returns to step 801.
Next, step 804 will be described. In step 804, controller 601 determines whether thawing of the stored object is completed. When the thawing of the stored object is completed, the processing proceeds to step 805. On the other hand, when the thawing of the stored object is not completed, the process returns to step 803. Conditions for determining that the thawing of the stored object is completed will be described later in detail.
Next, in step 805, controller 601 ends the output of the electromagnetic waves. At this time, controller 601 may display a message such as “Thawing is completed” on the display unit (not shown) of refrigerator 100, or may output a similar message by voice.
Note that a temperature of the stored object rises from the start to the end of the output of the electromagnetic waves. The rise in the temperature of the stored object leads to the rise in the temperature of thawing compartment 105. Thus, the temperature of thawing compartment 105 is desirably maintained in the freezing temperature range by controlling opening and closing operations of damper 203 while oscillator 206 outputs the electromagnetic waves. Further, the user does not always take out the stored object immediately after thawing of the stored object is completed. By maintaining the temperature of thawing compartment 105 in the freezing temperature range while oscillator 206 outputs the electromagnetic waves, the stored object is immediately frozen to maintain freshness of the stored object when the user does not immediately take out the stored object.
Next, the conditions for determining that the thawing of the stored object is completed will be described with reference to
As described above, the thawing of the stored object starts at time S1 and is completed at time S2. Assuming that a melting rate at time S1 is 0% and a melting rate at time S2 is 100%, ease of cutting with a kitchen knife and a drip amount are evaluated at five stages of the melting rate of 20%, 40%, 60%, 80%, and 100%. Results of this evaluation are shown in
As described above, according to the present exemplary embodiment, electromagnetic wave shield 213 of door 212 in which wiring to the grounding part is difficult can sufficiently exhibit the function as an electromagnetic wave shield. Further, refrigerator 100 does not output the electromagnetic waves while door 212 is open, and it is therefore possible to prevent the electromagnetic waves from leaking out of refrigerator 100 due to door 212 being open.
When door 212 is opened, high-humidity air flows into thawing compartment 105 from the outside of refrigerator 100. Then, when the heat treatment is started immediately after door 212 is closed, water vapor is generated from the stored object as the thawing of the stored object advances, and dew condensation easily occurs inside thawing compartment 105. The present exemplary embodiment therefore aims to reduce a possibility of dew condensation occurring inside thawing compartment 105 by not starting the heat treatment immediately after door 212 is closed.
When controller 601 determines in step 702 that door 212 is closed, the processing proceeds to step 1201. Then, in step 1201, controller 601 determines whether a predetermined time (for example, 1 minute) has elapsed since door 212 is closed. Refrigerator 100 has a clocking function such as a real time clock (RTC), and measures elapsed time after door 212 is closed. When the predetermined time has not elapsed since door 212 is closed, controller 601 stands by until the predetermined time has elapsed.
When controller 601 determines in step 807 that door 212 is closed, the processing proceeds to step 1301. Next, in step 1301, controller 601 stands by until a predetermined time (for example, 1 minute) has elapsed and restarts the output of the electromagnetic waves.
That is, in refrigerator 100 of the present exemplary embodiment, the heat treatment is not started until the predetermined time elapses after door 212 is closed. The cool air flowing through air passage 201 has low humidity, and thus refrigerator 100 can lower the humidity of thawing compartment 105 by standing by for a predetermined time and can start the heat treatment after lowering the humidity of thawing compartment 105. This can reduce the possibility that dew condensation occurs inside thawing compartment 105.
When defrosting is performed by defrosting heater 113, a large amount of water vapor flows from cooling compartment 110 into thawing compartment 105. When the heat treatment is started in this state, water vapor is generated from the stored object as the thawing of the stored object advances, and dew condensation easily occurs inside thawing compartment 105. Thus, in the present exemplary embodiment, damper 203 is closed while the defrosting by defrosting heater 113 is being performed. That is, in the present exemplary embodiment, by preventing the water vapor generated by defrosting from flowing into thawing compartment 105, it is possible to reduce the possibility that dew condensation occurs inside thawing compartment 105.
In the present exemplary embodiment, a modified example of thawing compartment 105 will be described. In each of the above exemplary embodiments, an example has been described in which oscillation electrode 208 is embedded in the entire top surface of thawing compartment 105 and counter electrode 209 is embedded in the entire bottom surface of thawing compartment 105. However, a region where oscillation electrode 208 and counter electrode 209 are embedded can be changed as appropriate. For example, as shown in
A modified example of thawing compartment 105 will be further described. For example, as shown in
In the present exemplary embodiment, a modified example of thawing compartment 105 will be described. In each of the above exemplary embodiments, an example has been described in which one set of oscillation electrode and counter electrode is provided in thawing compartment 105. However, a plurality of sets of oscillation electrodes and counter electrodes may be provided in thawing compartment 105. For example, as shown in
A modified example of thawing compartment 105 will be further described. For example, as shown in
In the present exemplary embodiment, a modified example of thawing compartment 105 will be described. For example, as shown in
According to a configuration of the present exemplary embodiment, first counter electrode 1803 and second counter electrode 1804 can also be used as electromagnetic wave shields. This eliminates the need for separately providing an electromagnetic wave shield above air passage 201 such as electromagnetic wave shield 210 in
In the present exemplary embodiment, an example will be described in which oscillator 206 and matching unit 207 are installed in a storage compartment different from thawing compartment 105. Oscillator 206 and matching unit 207 may be installed, for example, inside refrigerating compartment 103 located above thawing compartment 105. In particular, it is desirable to install oscillator 206 and matching unit 207 near a water supply tank for ice making provided in refrigerating compartment 103 and a water supply pipe that supplies water from the water supply tank to an ice making machine. With such an arrangement, heat generated from oscillator 206 and matching unit 207 is conducted to the water supply pipe, thereby preventing the water supply pipe from freezing.
In the present exemplary embodiment, a modified example of an installation position of the electromagnetic wave shield provided on door 212 will be described.
The present invention can be applied to household refrigerators and freezers, and commercial refrigerators and freezers.
Number | Date | Country | Kind |
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2018-079500 | Apr 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2019/014066 | 3/29/2019 | WO | 00 |