WO2012029309A1

WO2012029309A1 - Radio frequency heating apparatus

Info

Publication number: WO2012029309A1
Application number: PCT/JP2011/004876
Authority: WO
Inventors: 弘一朗川添; 孝之明石
Original assignee: パナソニック株式会社
Priority date: 2010-08-31
Filing date: 2011-08-31
Publication date: 2012-03-08
Also published as: CN103080655A; JP2012052690A

Abstract

To achieve safe operation by detecting the temperature and the vapor content in a heating chamber even in the event of abnormal heating and prevent premature switch off even for a frozen food on the market over which a heating sheet is used, whether the quantity of food is small or large is determined (step S7), abnormal heating of the food is detected on the basis of a threshold changed depending on whether the quantity of the food is small or large and the output level of a magnetron is lowered (step S9), and if the quantity of the food is small and if the vapor content in the heating chamber is a predetermined value or lower (step S14), the magnetron is stopped (step S12).

Description

High frequency heating device

The present invention relates to a high-frequency heating apparatus in which the food temperature in the heating chamber is detected by means of a surface temperature detection means and safety is taken into consideration.

Conventionally, high-frequency heating devices such as microwave ovens ensure safety by taking measures against abnormal heating due to misuse by the user. For example, the high-frequency heating device disclosed in Patent Document 1 calculates a change in weight from the initial stage of food when a vapor generated from the food is detected when high-frequency heating is performed. And this high frequency heating apparatus complete | finishes heating based on the comparison result of the weight change of the calculated foodstuff, and the abnormal heating determination weight computed from the time until it detects vapor | steam. Therefore, this high frequency heating apparatus can prevent abnormal heating of food (for example, refer to Patent Document 1).

In addition, the high-frequency heating device disclosed in Patent Document 2 estimates the size of the food not by the weight of the food but by the rise time of the ambient temperature in the heating chamber. And this high frequency heating apparatus sets the threshold value which lowers | hangs the output level of a high frequency generation means separately for a small load and a large addition based on the estimated magnitude | size of the foodstuff. Therefore, this high-frequency heating device can prevent abnormal heating even when heating with a small load (for example, see Patent Document 2).

Japanese Unexamined Patent Publication No. 2003-214632 Japanese Unexamined Patent Publication No. 2009-127924

The high-frequency heating device described in Patent Document 1 needs to measure the weight of food, and the weight of the food is measured through a mounting table on which the food is placed. In this case, if the mounting table is circular, weight measuring means can be provided under the shaft that supports the mounting table. However, in the case of a rectangular heating chamber, a space is created where food cannot be placed outside the circular mounting table. For this reason, in the high-frequency heating device described in Patent Document 1, the amount of food that can be cooked at one time is equivalent to the area of the mounting table, and the area of the bottom surface of the heating chamber cannot be used effectively. Therefore, a high-frequency heating device such as a microwave oven has a meaning of improving the cleanability, and in recent years, a configuration in which the bottom surface of the heating chamber is formed in a flat shape has been dominant. However, in such a high-frequency heating apparatus, the bottom surface of the heating chamber is fixed to the heating chamber, and it is difficult to provide weight measuring means. Therefore, in the high-frequency heating device described in Patent Document 1, even if the weight measuring means can be provided, the number of parts increases and the product becomes expensive.

For this reason, in recent years, many high-frequency heating devices equipped with an infrared sensor for detecting the surface temperature of food have been put on the market instead of weighing. The high-frequency heating device is determined to be abnormal when the surface temperature of the food detected by the infrared sensor reaches a predetermined temperature, and stops heating. Since this infrared sensor detects the surface temperature of the food, this high-frequency heating device can perform automatic heating that automatically stops heating based on the output of the infrared sensor when the food reaches an appropriate temperature.

However, when the user sets an arbitrary time for operation (hereinafter also referred to as “manual heating”), heating to an appropriate temperature depends on the heating power selected by the user and the set time. In other words, this high-frequency heating device operates by setting the heating power and the heating time according to the size and type of food with reference to the user's experience and information described in the instruction manual. Therefore, the high-frequency heating device operates regardless of whether the set heating power and heating time are appropriate. Therefore, the high-frequency heating apparatus is concerned that food may be abnormally heated when the set heating conditions are not appropriate.

Therefore, it is conceivable to improve the safety by using the infrared sensor during this “manual heating” and configuring the high-frequency heating device to reduce the heating power when the infrared sensor detects an abnormally high temperature. However, recently, among frozen foods on the market, foodstuffs for microwave ovens characterized by being burnt using a heat-generating sheet heated at high frequency have been put on the market. Therefore, simply detecting the high temperature and dropping the heating power causes the infrared sensor to detect the high temperature of the heat generating sheet, and the frozen food is not heated sufficiently, and the operation of the high-frequency heating device stops while it is cold There is.

The high-frequency heating device described in Patent Document 2 is such that when a user heats a small amount of food, the ambient temperature in the heating chamber is accidentally increased even when heating is started with a large heating power and a long heating time. If it is detected that the food temperature in the heating chamber has become high, the heating power is reduced so that the heating does not proceed further. Therefore, this high frequency heating device can prevent abnormal heating of food. Furthermore, in this high-frequency heating device, when heating frozen food using a heat generating sheet, the heat generating sheet becomes high temperature after the start of heating, but until the increase in the atmospheric temperature in the heating chamber is detected, the heating power Do not reduce. Therefore, in this high-frequency heating device, the heating is not terminated and the heating is not finished while being frozen.

However, the high-frequency heating device described in Patent Document 2 has a problem in that in the case of a small amount of food that easily rises in temperature, the food is abnormally heated and the temperature rises rapidly.

The present invention solves the above-mentioned conventional problems, and even in the case of abnormal heating, it can be operated safely by detecting the temperature and the amount of steam in the heating chamber, and a commercial refrigeration using a heat generating sheet. An object of the present invention is to provide a high-frequency heating device that prevents food from being cut quickly.

In order to solve the above-described conventional problems, a high-frequency heating device of the present invention includes a heating chamber for storing food, high-frequency generating means for generating a high frequency for dielectrically heating food in the heating chamber, Surface temperature detection means that is disposed outside the wall surface and detects the temperature of the food in the heating chamber in a non-contact manner, chamber temperature detection means for detecting the atmospheric temperature in the heating chamber, and a chamber that detects the amount of steam in the heating chamber An internal steam detection means, and a controller for controlling the output of the high-frequency generation means based on the output from the surface temperature detection means, the internal temperature detection means, and the internal steam detection means, the control part, When the user inputs a heating start operation at an arbitrary time, it is judged whether the food is small or large, and the threshold is changed depending on whether the food is small or large, and abnormal heating of the food is detected. Said high frequency generating means With lowering the output level, if the food was small, steam volume of the heating chamber is configured so as to stop the high frequency generating means is equal to or less than a predetermined value.

With the above configuration, when the user heats a small amount of food, even if the heating power is mistakenly increased and the heating time is set to be long and the heating is started, an increase in the atmospheric temperature in the heating chamber is detected and heating is performed. If it is determined that the temperature of the food in the room has become high, the heating power is reduced so that the heating does not proceed further, so that abnormal heating of the food can be prevented. In addition, when heating frozen food using a heat generating sheet, the heat generating sheet becomes high temperature after the start of heating, but heating power is not reduced until an increase in the atmospheric temperature in the heating chamber is detected. There is no longer a situation where the heating is finished while it is cut and frozen.

According to the present invention, abnormal heating when manually heating a small amount of food can be prevented, and premature cutting when heating frozen food using a heating sheet can be prevented, and safe and reliable high-frequency heating. Equipment can be provided.

System schematic diagram of high-frequency heating apparatus in Embodiment 1 of the present invention The front view which shows the state which opened the opening-and-closing door of the high frequency heating apparatus in this Embodiment Configuration diagram of the machine room viewed from the right side of the high-frequency heating device in the present embodiment Block diagram showing the electrical configuration of the control unit Flow chart showing the control contents of the control unit Flow chart showing the control contents when the food in the control unit is large Explanatory drawing which shows the temperature acquisition area of the infrared sensor of the high frequency heating apparatus in this Embodiment

As one aspect of the present invention, a high-frequency heating apparatus includes a heating chamber for storing food, high-frequency generating means for generating a high frequency for dielectrically heating the food in the heating chamber, and disposed outside the wall surface of the heating chamber. Surface temperature detection means for detecting the temperature of the food in the heating chamber in a non-contact manner, chamber temperature detection means for detecting the atmospheric temperature in the heating chamber, and steam detection means for detecting the amount of steam in the heating chamber; And a controller for controlling the output of the high-frequency generating means based on the output from the surface temperature detecting means, the internal temperature detecting means, and the internal steam detecting means. When the user sets an arbitrary time and inputs a heating start operation, the control unit determines whether the food is small or large, and changes the threshold value depending on whether the food is small or large. When the heating is detected to reduce the output level of the high frequency generating means, and the amount of food in the heating chamber is less than a predetermined value when the amount of food is small, the high frequency generating means is stopped. With this configuration, it is possible to prevent abnormal heating when manually heating a small amount of food, and it is possible to prevent premature cutting when heating frozen food using a heating sheet.

In the above-described high-frequency heating device, when the user inputs a heating start operation with an arbitrary time set by the user, the amount of steam in the heating chamber is less than or equal to a predetermined value when the amount of food is small. If it continues for a predetermined time, the high frequency generating means is stopped. With this configuration, it is possible to prevent abnormal heating when manually heating a small amount of food, and it is possible to prevent premature cutting when heating frozen food using a heating sheet.

In the above high-frequency heating device, when the user inputs a heating start operation by setting an arbitrary time, the control unit, when the amount of food is small, the atmospheric temperature in the heating chamber is equal to or higher than a predetermined value, and When the state in which the amount of steam in the heating chamber is below a predetermined value continues for a predetermined time, the high-frequency generating means is stopped. With this configuration, it is possible to prevent premature breakage when heating frozen food using a heating sheet.

In the above high-frequency heating device, the detection of the atmospheric temperature in the heating chamber and the detection of the amount of steam in the heating chamber are performed by a single thermistor, so that the number of parts can be reduced and the configuration can be simplified.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

FIG. 1 is a system schematic diagram of a high-frequency heating device according to an embodiment of the present invention. FIG. 2 is a front view showing a state in which the open / close door of the high-frequency heating device in the present embodiment is opened. FIG. 3 is a configuration diagram of the machine room as viewed from the right side in the high-frequency heating device of the present embodiment. FIG. 4 is a block diagram showing an electrical configuration of the high-frequency heating device of the present embodiment. 5 and 6 are flowcharts for explaining the operation of the high-frequency heating device of the present embodiment.

A dish tray 2 in which crystallized glass that becomes the bottom surface of the heating chamber is cut to the inside of the heating chamber 1 is inserted on the bottom surface of the heating chamber 1, and the food 3 is placed on the dish tray 2. A temperature detection hole 4 is formed above the right side surface of the heating chamber 1, and an infrared sensor 5 functioning as a surface temperature detection means disposed outside the wall surface of the heating chamber 1 is disposed oppositely. The infrared sensor 5 detects the surface temperature of the food 3 in the heating chamber 1 in a non-contact manner. The infrared sensor 5 is repeatedly operated in the direction indicated by the arrow by the drive motor 6 so that the temperature in a predetermined range of the bottom surface portion in the heating chamber 1 can be detected.

A heating chamber thermistor 7 that functions as an internal temperature detection means for measuring the atmospheric temperature in the heating chamber 1 is provided at the right rear of the top surface of the heating chamber 1.

The control unit 8 is mainly composed of a microcomputer and controls the operation of the drive motor 6. The control unit 8 A / D converts the signal voltage obtained from the infrared sensor 5 and the signal voltage obtained from the thermistor 7 for the heating chamber, and the A / D converted temperature data of the food 3 and the predetermined food 3 The judgment value of finishing temperature is compared and the heating time of the food 3 is determined. Moreover, the control part 8 controls the output of the high frequency generation means mentioned later.

In the back of the heating chamber 1, there is disposed a water reservoir 10 for boiling the water supplied from the nozzle 9 to generate steam.

A door 11 is provided in front of the heating chamber 1 so that it can be opened and closed. Further, an operation panel 13 having various operation keys 11a to 11d for a user to select a heating menu and give instructions for starting heating and a display 12 for performing necessary display is provided on the front surface of the heating chamber 1. A control board (not shown) is disposed on the back side of the operation panel 13, and a control circuit 8 and a drive circuit 14 for operating the high frequency generating means are provided on the control board. A machine room is provided behind the operation panel 13.

In the machine room, a magnetron 15 that is located on the right side wall of the heating chamber 1 and functions as high-frequency generating means is disposed. A cooling fan 17 and an air guide 18 attached to the back plate 16 are arranged on the right side of the magnetron 15. Air blown from the cooling fan 17 is guided to the magnetron 15 by the air guide 18 to cool the magnetron 15. An air guide 19 is installed on the left side of the magnetron 15 to send air into the heating chamber 1. The air guide 19 is provided with an exhaust thermistor 20 that detects the temperature of the magnetron 15. The high frequency oscillated from the magnetron 15 supplies microwaves into the heating chamber 1 from a power supply port (not shown) provided on the bottom surface of the main body via a waveguide (not shown). An inverter 21 that varies the output of the magnetron 15 is disposed above the magnetron 15. An infrared sensor 5 is arranged between the inverter 21 and a lamp or the like that illuminates the inside of the heating chamber 1. The upper heater 22 functions as a lamp that illuminates the inside of the heating chamber 1.

FIG. 4 shows the electrical configuration of the high-frequency heating device of the first embodiment. In FIG. 4, the control unit 8 includes various operation keys 11a to 11d including a start switch, an infrared sensor 5, an exhaust thermistor 20 that detects the temperature of the magnetron 15, and a heating chamber that detects the temperature in the heating chamber 1. A signal from the thermistor 7 is input. Based on these signals, the control unit 8 displays information on the heating time and accessories on the display 12 according to a program stored in advance, and via the drive circuit 14, the magnetron 15, the upper heater 22, the lower heater 23, the cooling The fan 17, the steam heater 24, and the drive motor 6 are controlled. Since the magnetron 15 is controlled via the inverter 21, the output can be controlled. For example, the steam heater 24 and the high frequency output (for example, 300 W) can be used simultaneously.

The operation of the high-frequency heating device of the present embodiment configured as described above will be described with reference to the flowcharts of FIGS.

FIG. 5 and FIG. 6 show portions related to the gist of the present invention among the contents of control by the control unit 8, and this will be described below together with related operations.

When the user heats the food, the output power of the high frequency heating is selected by tapping the “range output switching” key of the operation key 11b (step S1). The high-frequency heating device of the present embodiment is set to switch to the order of 600 W, 500 W, and 150 W every time a tap is selected when it is first pressed. Here, it is assumed that 800 W output is selected.

Next, the user sets the time to be operated by turning the dial of the operation key 11c (step S2). When the user selects the output power of the high frequency heating as 800 W, the maximum heating time can be selected up to 10 minutes. Similarly, when the user selects the output power of the high frequency heating as 600 W or 500 W, the maximum heating time can be selected up to 30 minutes. Furthermore, when the user selects the output power of the high frequency heating to 150 W, it is set so that it can be selected up to 5 hours.

Next, the user presses a “start” key for instructing the start of heating, and heating is started (step S3). Simultaneously with the start of heating, the control unit 8 operates the drive motor 6 via the drive circuit 14.

During heating, the controller 8 first monitors whether or not the door 11 has been opened as a determination of whether or not to stop heating (step S4). When the door 11 remains closed, the control unit 8 monitors whether or not the “cancel” key of the operation key 11d is pressed (step S5). Even if the heating operation time set by the user has not been reached, the high-frequency heating device of the present embodiment opens the door 11 (step S4) or presses the “cancel” key (step S5). Heating can be stopped at an arbitrary time (step S12).

In step S6, it is determined whether or not the temperature in the heating chamber 1 has increased and reached T ° C. This is because the temperature in the heating chamber 1 is maintained at the starting temperature for a while after the heating is started. As the heating proceeds, steam starts to be generated from the food, and the temperature in the heating chamber 1 also rises. The determination value T ° C. for determining whether the food is sufficiently heated was set to 80 ° C. by experiment. When the temperature does not exceed 80 ° C. in step S6, it is determined that the heating is not abnormal, and the process proceeds to step S7.

Next, the predetermined value of the food temperature is distinguished and set depending on whether the amount of food is large or small (step S7). When the temperature in the heating chamber 1 becomes 80 ° C. or higher in step S6, the time from the start of heating until the temperature of the heating chamber 1 becomes 80 ° C. or higher is measured and compared with a preset X time. I do.

If the amount of food is small, two determinations are made in parallel. First, in the first determination, the temperature detected by the infrared sensor 5 (hereinafter referred to as “IR detection temperature”) is compared with a threshold temperature for a small load (in this embodiment, set to 92 ° C.) (step S8). . As a result of the comparison, if the IR detection temperature is equal to or higher than the threshold temperature, the output of the magnetron 15 functioning as the high-frequency generating means is reduced to alleviate heating (step S9).

Further, when the IR detection temperature is equal to or lower than the threshold temperature, it is determined whether or not the cooking time set for the heating time has been reached (step S11).

Then, the output of the magnetron 15 is reduced, and after a predetermined time has elapsed, the temperature detected by the infrared sensor 5 is again compared with the first abnormal heating temperature (98 ° C. in the present embodiment) (step S10). When the IR detection temperature is higher than the first abnormal heating temperature, after a predetermined time, it is compared with the second abnormal heating temperature (92 ° C.). When the IR detection temperature is higher than the second abnormal heating temperature, the magnetron 15 is stopped, and when the IR detection temperature is lower than the second abnormal heating temperature, heating is performed in the reduced output state until the cooking time ends (step S11).

The second determination when the amount of food is small is to compare whether the food is sufficiently heated and the internal temperature with a threshold (step S13). In the present embodiment, this threshold is set to 80 ° C. When the internal temperature reaches 80 ° C. or higher, the amount of steam in the heating chamber 1 is detected (step S14).

When the amount of steam in the heating chamber 1 is less than the predetermined amount, it is determined that the steam has come out from the food, and the operation of the magnetron 15 is stopped so as not to abnormally heat the food (step S12). For detecting the amount of steam, a heating chamber thermistor 7 serving as a chamber temperature detecting means for measuring the ambient temperature in the heating chamber 1 was also used as a steam sensor.

If the amount of food is large, in step S15, the temperature detected by the infrared sensor 5 is compared with the threshold temperature for mass load (in this embodiment, set to 98 ° C.), as in the case of a small amount of food. (Step S15). As a result of the comparison, if the IR detection temperature is equal to or higher than the threshold temperature, the output of the magnetron 15 that is the high-frequency generating means is reduced to relax the heating (step S16).

Further, when the IR detection temperature is equal to or lower than the threshold temperature, it is determined whether or not the cooking time set for the heating time has been reached (step S17).

Then, the output of the magnetron 15 is reduced, and after a predetermined time has elapsed, the temperature detected by the infrared sensor 5 is again compared with the first abnormal heating temperature (110 ° C.) (step S18). When the IR detection temperature is higher than the first abnormal heating temperature, after a predetermined time, it is compared with the second abnormal heating temperature (105 ° C.). When the IR detection temperature is higher than the second abnormal heating temperature, the magnetron 15 is stopped, and when the IR detection temperature is lower than the second abnormal heating temperature, heating is performed until the cooking time ends in the reduced output state (step S19).

FIG. 7 shows a reading range of the infrared sensor 5 in the high-frequency heating device of the present embodiment. The infrared sensor 5 has 8 elements and reciprocates by the drive motor 6 so as to detect the entire inside of the heating chamber 1. Therefore, the detection area is as shown by the hatched portion in FIG. When a potato-like object 3a is placed in the center of the heating chamber 1, the food is larger than the detection area shown in FIG. 7, and therefore the temperature of the food itself can be detected. When the remaining food material, for example, an object 3b having a size such as a sweet potato piece 50g is placed on the left side in the heating chamber 1, as shown in FIG. 7, food partially enters the detection area. The average temperature is acquired together with the parts other than the surrounding food, and the temperature of the complete food is not acquired, but a temperature lower than the food temperature is detected.

Specific explanation will be given for the case where one potato is heated. Normally, heating can be performed appropriately by heating at 600 W for 4 minutes, but it is assumed that the user sets the output power of high-frequency heating to 800 W and the heating time to 10 minutes. After the start of heating, it took 2 minutes and 30 seconds for the atmospheric temperature of the heating chamber to rise by 10 ° C. The detection temperature of the food at this time was 95 ° C. Since 115 ° C. of threshold value 2 has not been reached, the heating power of 800 W is continued. Thereafter, as the heating continued, the food temperature rose and reached 115 ° C. in 6 minutes and 50 seconds. At this point, the heating power is lowered to 300 W and heating is continued. Since the heating power was reduced, the temperature rise of the food (potato) was suppressed, and when the set 10 minutes had passed, it reached 119 ° C., but there was no abnormal heating of the potato.

Next, the case where the frozen pizza is heated will be described. Among commercially available frozen pizzas, there is a type in which a sheet that generates heat at a high frequency is laid on the bottom of the food and the bottom is burnt. For a frozen pizza with a diameter of about 15 cm, the output power of high frequency heating is 600 W and the heating time is 2 minutes to 2 minutes 30 seconds. Depending on the radio wave distribution of the high-frequency heating device, there are many cases where heating is insufficient in the time recommended by the food manufacturer. Therefore, in the experiment at the examination stage, it was set to 3 minutes and 30 seconds and the situation was observed. When heating was started, the detected temperature of the food became 120 ° C. 20 seconds after the start of heating, the heating power dropped to 300 W, and when the heating was stopped, a cold part remained. Although the frozen pizza is circular, the heating sheet is quadrangular, so the four corners of the heating sheet are visible, and the infrared sensor 5 acquires the temperature. At the examination stage, the power was reduced by detecting high temperature, but there was a problem with foods such as those with a heating sheet, but in the high-frequency heating device according to the embodiment of the present invention, an increase in the internal temperature was added to the judgment. This problem can be solved. That is, when the frozen pizza is heated again with the high-frequency heating device according to the embodiment of the present invention, the rise in the internal temperature is 7 ° C. at the time of 3 minutes and 30 seconds, and the food temperature determination step after step S9 is performed. The frozen pizza could be heated without any problems because it did not shift and the heating power did not decrease.

In this embodiment, the determination in step S6 is performed every 20 seconds at the start of heating, and is continuously acquired when the temperature in the heating chamber 1 rises by 10 ° C. or more and shifts to step S9. In the case of the automatic heating menu that detects the temperature of the food and stops heating, the temperature of the food is always monitored, but in the case of manual heating where the user sets the heating time and operates, temperature detection Therefore, the frequency of temperature detection is reduced to 1/5 and the durability of the driving device is taken into consideration, as compared with the case of the automatic heating menu. If the infrared sensor is driven when food is heated, the lens surface of the infrared sensor may be contaminated due to the scattering of food caused by the heated food popping. Considered.

In this embodiment, the reciprocating operation for detecting the temperature of the food is performed for the first time when the heating time setting of the user is set longer than 3 minutes. Usually, food does not reach abnormal heating by heating in a short time. In the case of warming drinks or reheating foods, it will be heated enough in 3 minutes or less, so there is no need to perform a reciprocating operation for detecting abnormalities in the range of general use. It has a structure that takes into account the nature.

As described above, even when the user mistakenly sets the heating power and heating time and starts heating, the temperature rise in the heating chamber 1 and a higher temperature than when normal food is heated are detected. Thus, by reducing the output power of the high-frequency output while preventing malfunction, abnormal heating of the food can be prevented and it can be used safely.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

This application is based on a Japanese patent application filed on August 31, 2010 (Japanese Patent Application No. 2010-193455), the contents of which are incorporated herein by reference.

As described above, according to the high-frequency heating device according to the present invention, even when a user starts heating with a large heating power for a small amount of food and a long heating time, abnormal heating can be prevented, It is possible to prevent premature breakage when heating frozen food using a heating sheet, and to provide a safe and reliable high-frequency heating device.

DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Dish stand 3

Food

3a, 3b Object 4 Hole for temperature detection 5 Infrared sensor (surface temperature detection means)
6 Drive motor 7 Thermistor for heating chamber (internal temperature detection means)
8 Control Unit 9 Nozzle 10 Water Reservoir 11 Door 11a to 11d Operation Key 12 Display 13 Operation Panel 14 Drive Circuit 15 Magnetron (High Frequency Generation Means)
16 Back plate 17 Cooling

fan

18, 19 Air guide 20 Exhaust thermistor 21 Inverter 22 Upper heater 23 Lower heater 24 Steam heater

Claims

A heating chamber for storing food,
High frequency generating means for generating a high frequency for dielectric heating the food in the heating chamber;
A surface temperature detecting means that is disposed outside the wall surface of the heating chamber and detects the temperature of food in the heating chamber in a non-contact manner;
An internal temperature detecting means for detecting an atmospheric temperature in the heating chamber;
In-compartment steam detection means for detecting the amount of steam in the heating chamber;
A controller that controls the output of the high-frequency generator based on the output from the surface temperature detector, the internal temperature detector, and the internal steam detector;
When the user inputs a heating start operation after setting an arbitrary time, the control unit determines whether the food is small or large, and changes the threshold value depending on whether the food is small or large. Detecting heating and lowering the output level of the high-frequency generating means, and when the amount of food is small, if the amount of steam in the heating chamber is less than a predetermined value, the high-frequency generating means is stopped,
A high-frequency heating device characterized by that.
The controller is
When the user sets an arbitrary time and inputs a heating start operation, if the amount of food is small, the high-frequency generating means is stopped when the amount of steam in the heating chamber continues below a predetermined value for a predetermined time. ,
The high frequency heating device according to claim 1.
The controller is
When the user sets an arbitrary time and inputs a heating start operation, when the amount of food is small, the atmospheric temperature in the heating chamber is equal to or higher than a predetermined value, and the amount of steam in the heating chamber is equal to or lower than the predetermined value. Stop the high-frequency generating means when the state continues for a predetermined time,
The high-frequency heating device according to claim 1 or 2.
The detection of the atmospheric temperature in the heating chamber and the detection of the amount of steam in the heating chamber are performed with one thermistor.
The high frequency heating device according to any one of claims 1 to 3.