WO2024185156A1

WO2024185156A1 - High frequency heating cooker

Info

Publication number: WO2024185156A1
Application number: PCT/JP2023/023855
Authority: WO
Inventors: 恵安島; 香織竹中; 友秀松井
Original assignee: 日立グローバルライフソリューションズ株式会社
Priority date: 2023-03-08
Filing date: 2023-06-27
Publication date: 2024-09-12
Also published as: JP2024126646A

Abstract

Provided is a high frequency heating cooker which, when continuously cooking a plurality of objects to be heated by heating, is capable of calculating an appropriate heating time for the current object to be heated, even if the temperature of a placement location, or the like, of the objects to be heated has risen during the previous heating. The high frequency heating cooker comprises an oven heating unit, an infrared sensor for detecting temperatures at a plurality of places on an upper surface of a table plate, an out-of-compartment temperature sensor, a recording unit for recording a previous heating operation, a timer for measuring an elapsed time from the end of the previous heating operation to the start of the current heating operation, and a control unit for controlling the oven heating unit, wherein, if the previous heating operation was oven heating, the time measured by the timer is shorter than a predetermined time, and the maximum temperature among the temperatures of the upper surface of the table plate is higher than a predetermined temperature, the control unit classifies the state of the object to be heated as frozen or not frozen on the basis of the initial temperature of the object to be heated, detected by the infrared sensor, calculates a heating time corresponding to the classified state, and controls the oven heating unit.

Description

High frequency cooking equipment

The present invention relates to a high-frequency cooking device that uses microwaves to heat and cook food.

Some conventional high-frequency cooking devices set the microwave cooking time based on the storage state of the food placed in the heating chamber. For example, the abstract of Patent Document 1 discloses a high-frequency cooking device that "enables the heating of the object to an appropriate temperature regardless of the storage state, amount, or initial surface temperature of the object," and that "includes a heating means for heating the object to be heated, a table plate on which the object to be heated is placed in the heating chamber, a weight sensor that supports the table plate and measures the weight of the object to be heated, a temperature sensor that detects the temperature of the non-heated object, and a control means that controls the heating means based on the detection values of the weight sensor and the temperature sensor so as to reach the finishing temperature, and the control means detects the temperature rise of the object to be heated with the temperature sensor, determines whether the object to be heated is frozen or not as a storage state according to the detected temperature rise, calculates a heating time according to the storage state of the object to be heated, and heats the object to be heated." Claim 5 of the same document also states that "the temperature sensor is an infrared sensor."

In this way, the high-frequency cooking device of Patent Document 1 determines whether the object is frozen or not based on the temperature rise of the object detected by a non-contact temperature sensor (infrared sensor), and calculates the cooking time according to the result of the determination, thereby appropriately cooking the object (see Figures 13 to 15 of the same document).

JP 2019-211171 A

However, the high-frequency heating device in Patent Document 1 does not anticipate a situation in which one food is cooked immediately after another, and there are cases in which the latter food cannot be cooked properly. This problem will be specifically explained using the example of a situation in which rice is heated immediately after a side dish is heated.

In this case, the temperature of the table plate where the side dish is placed also rises when the side dish is heated, so when the side dish is removed after cooking is finished, there will be a part of the table plate top that is hotter than room temperature. If rice is then placed in a position different from where the side dish was placed and cooking begins, the temperature sensor (infrared sensor) in Patent Document 1 cannot determine whether the high-temperature part of the table plate top is the food to be cooked (the object to be heated). Therefore, the high-frequency heating device in Patent Document 1 may mistake the high-temperature part of the table plate top (the part where the side dish was placed until just before) for the object to be heated and calculate an inappropriate rice heating time based on the temperature change there, which may cause the rice to be heated improperly.

The present invention aims to provide a high-frequency cooking device that can calculate the appropriate heating time for the current heated object when cooking multiple heated objects consecutively, even if the temperature of the place where the heated object is placed has risen during the previous heating.

The high frequency heating cooker of the present invention has been made to achieve the above object, and comprises a heating chamber housing a table plate, a microwave heating unit for heating an object placed on the table plate, an infrared sensor for detecting the temperature at multiple points on the top surface of the table plate, an outside temperature sensor for detecting the temperature outside the heating chamber, a recording unit for recording the previous heating operation, a timer for measuring the elapsed time from the end of the previous heating operation to the start of the current heating operation, and a control unit for controlling the microwave heating unit, and when the previous heating operation recorded in the recording unit was microwave heating, the measured time of the timer is shorter than a predetermined time, and the maximum temperature of the temperature of the top surface of the table plate detected by the infrared sensor is higher than the predetermined temperature, the control unit classifies the state of the object to be heated as frozen or not based on the initial temperature of the object to be heated detected by the infrared sensor, calculates the heating time according to the classified state, and controls the microwave heating unit.

The high-frequency cooking device of the present invention can calculate the appropriate heating time for multiple objects to be heated this time when cooking multiple objects in succession, even if the temperature of the object's placement, etc., has risen during the previous heating.

1 is a front perspective view of a cooking device according to an embodiment; FIG. 2 is a rear perspective view of the cooking device according to the embodiment with the outer frame removed. AA cross-sectional view of FIG. In FIG. 3, an explanatory diagram of the operation of the infrared sensor when heating cold rice in a bowl FIG. 4 is a flowchart illustrating control of a cooking device according to an embodiment. FIG. 2 is a control block diagram of a cooking device according to an embodiment. FIG. 4 is a diagram for explaining a heating time of a cooking device according to an embodiment.

The following describes an embodiment of the present invention with reference to the attached drawings.

FIGS. 1 to 3 show the main parts of this embodiment, with FIG. 1 being a perspective view of the cooking device body as seen from the front side, FIG. 2 being a perspective view of the cooking device body as seen from the rear side with the outer frame removed, and FIG. 3 being a cross-sectional view taken along line A-A in FIG. 1.

In the figure, the main body 1 of the cooking device has food to be heated placed in the heating chamber 28, and the food is cooked using microwaves, heater heat, or superheated steam.

Door 2 opens and closes to put food in and take it out of the heating chamber 28. Closing door 2 seals the heating chamber 28, preventing the leakage of microwaves used to heat food and sealing in the heater heat and superheated steam, allowing for efficient heating.

The handle 9 is attached to the door 2 and makes it easy to open and close the door 2, and is shaped to be easy to grip with the hand.

The glass window 3 is attached to the door 2 so that the state of the food being cooked can be checked, and is made of glass that can withstand high temperatures caused by heaters, etc.

The input unit 71 is provided on the operation panel 4 on the lower front side of the door 2, and is composed of an operation unit 6 for inputting the heating unit (such as microwave heating or heater heating), the heating time, and the heating temperature, and a display unit 5 for displaying the contents inputted from the operation unit 6 and the progress of cooking.

The outer frame 7 is a cabinet that covers the top and left and right sides of the cooking device's main body 1.

The water tank 42 is a container that stores the water needed to make heated steam.

The rear panel 10 forms the rear surface of the cabinet, and has an external exhaust duct 18 attached to the top. Steam emitted from food and cooling air (waste heat) 39 after cooling the internal parts of the main body 1 are exhausted from the external exhaust port 8 of the external exhaust duct 18.

The machine chamber 20 is provided in the space between the bottom surface 28a of the heating chamber and the bottom plate 21 of the main body 1, and on the bottom plate 21 are mounted a magnetron 33 for heating food, a waveguide 47 connected to the magnetron 33, a control board 23 on which a control unit 23a, a recording unit 100, a timer 101 (see Figure 7), and other various components described below, and a fan unit 15 for cooling these various components.

The bottom surface 28a of the heating chamber is recessed in approximately the center, within which the rotating antenna 26 is installed, and microwave energy radiated from the magnetron 33 flows into the underside of the rotating antenna 26 through the waveguide 47 and the aperture 47a through which the output shaft 46a of the rotating antenna 26 passes, and is diffused by the rotating antenna 26 before being radiated into the heating chamber 28. The output shaft 46a of the rotating antenna 26 is connected to the rotating antenna drive unit 46.

The fan unit 15 is composed of a cooling fan attached to a cooling motor attached to the bottom plate 21. The cooling air 39 generated by this fan unit 15 cools the magnetron 33, which generates heat, the inverter circuit (not shown), the rear weight sensor 25c, the left weight sensor 25b, and the like in the machine room 20. It also flows between the outside of the heating chamber 28 and the outer frame 7, and between the hot air case 11a and the rear plate 10 as described above, and is discharged from the external exhaust port 8 of the external exhaust duct 18 while cooling the outer frame 7 and the rear plate 10. In addition, a duct 16a for cooling the hot air motor 13 described later and a duct 16b for cooling the infrared unit 50 housed in the infrared case 48 described later are provided, and the cooling air 39 that has cooled the infrared unit 50 is discharged from the opposite side of the exhaust duct 28e that disposes of the exhaust heat (such as water vapor) in the heating chamber 28, and then discharged outside from the external exhaust duct 18.

The microwave heating unit 330 (Figure 7) consists of a magnetron 33 and an inverter circuit (not shown) and is controlled by the control unit 23a.

A hot air unit 11 is attached to the rear of the heating chamber 28, and a hot air fan 32 is attached inside the hot air unit 11 to efficiently circulate the air inside the heating chamber 28. The rear wall surface 28b of the heating chamber is provided with hot air intake holes 31 and hot air outlet holes 30 that serve as air passages.

The hot air fan 32 rotates when driven by a hot air motor 13 attached to the outside of the hot air case 11a, and heats the air circulating through the hot air heater 14.

The hot air unit 11 also has a hot air case 11a at the rear of the inner wall surface 28b of the heating chamber, a hot air fan 32 between the inner wall surface 28b of the heating chamber and the hot air case 11a, and a hot air heater 14 positioned on its outer periphery. A hot air motor 13 is attached to the rear of the hot air case 11a, and the motor shaft is connected to the hot air fan 32 through a hole provided in the hot air case 11a.

The hot air motor 13 rises in temperature due to heat from the heating chamber 28 and the hot air heater 14, so to prevent this, it is surrounded by a hot air motor cover 17, and the duct 16a is formed in an approximately cylindrical shape and positioned between the hot air case 11a and the rear panel 10. The upper end opening of the duct 16a is connected to the underside of the hot air motor cover 17, and the lower end opening is connected to the outlet of the fan device 15, so that part of the cooling air 39 from the fan device 15 is taken into the hot air motor cover 17.

A grill heating unit 12 consisting of a heater is attached to the underside of the heating chamber top surface 28c of the heating chamber 28. The grill heating unit 12 is formed into a flat shape by wrapping a heater wire around a mica plate and pressing it against the underside of the top surface of the heating chamber 28 to fix it in place. It heats the top surface of the heating chamber 28 and grills the food inside the heating chamber 28 by radiant heat.

Furthermore, an infrared unit 50 (described later) is provided at the rear of the heating chamber top surface 28c of the heating chamber 28, and is covered with an infrared case 48 to cool the infrared unit 50. The duct 16b is formed in a roughly cylindrical shape and is positioned between the hot air case 11a and the rear panel 10, with the upper end opening of the duct 16b connected to the side of the infrared case 48 and the lower end opening connected to the top surface of the hot air motor cover 17, and takes in some of the cooling air 39 from the fan device 15.

An internal temperature sensor 80 (thermistor) that detects the ambient temperature of the heating chamber 28 (hereinafter referred to as the "internal temperature Ti") is provided at the rear left side of the heating chamber top surface 28c of the heating chamber 28.

The bottom surface 28a of the heating chamber is provided with multiple weight sensors 25, such as a left weight sensor 25b and a right weight sensor (not shown) on the front left and right, and a rear weight sensor 25c in the center of the rear side, on which the table plate 24 is placed.

The table plate 24 is for placing food on and is made of a heat-resistant material that is suitable for both heater and microwave heating, and is also highly permeable to microwaves.

The boiler 43 is attached to the outer surface of the hot air case 11a of the hot air unit 11, and the saturated water vapor is directed into the hot air unit 11. The saturated water vapor ejected into the hot air unit 11 is heated by the hot air heater 14 and becomes superheated water vapor.

The pump section 87 pumps water from the water tank 42 up to the boiler 43, and is composed of a pump and a motor that drives the pump.

The heating parts include the range heating part 330, the hot air heater 14, the hot air motor 13, the grill heating part 12, the boiler 43, etc.

Next, we will use Figures 4 and 5 to provide a detailed explanation of the infrared sensor 52 that is installed above the heating chamber 28 and detects the temperature of the object to be heated in a non-contact manner.

Figure 4 is an explanatory diagram of the operation of the infrared sensor when rice is placed in a bowl and heated using the cross-sectional view shown in Figure 3, and Figure 5 is an explanatory enlarged view of the infrared sensor.

51 denotes a motor, which is attached so that its rotation axis 51a is parallel to the inner wall surface 28b of the heating chamber. The rotation axis 51a rotates (drives) a cylindrical unit case 54, which will be described later, which rotates a board 53 carrying an infrared sensor 52 housed in the unit case 54, and the lens portion 52a of the infrared sensor 52 rotates and moves within a range from the inner side of the bottom surface 28a of the heating chamber (the inner wall surface 28b side of the heating chamber) to the heating chamber opening 28d, allowing the temperature to be detected. The motor 51 uses a stepping motor, and the rotation axis 51a can be rotated forward or backward and at any desired rotation angle under the control of a control unit 23a provided on the control board 23.

Infrared sensor 52 detects the temperature of table plate 24 and heated object 60c without contact. In this embodiment, infrared sensor 52 is configured by arranging eight infrared detection elements (e.g. thermopiles) in a row on substrate 53 in the direction of rotation axis 51a. Therefore, infrared sensor 52 of this embodiment can simultaneously detect the temperature of eight locations on table plate 24. In addition, infrared sensor 52 of this embodiment can detect the temperature of the entire table plate 24 by rotating substrate 53 on which the group of infrared detection elements is mounted, around rotation axis 51a.

54 is a cylindrical unit case, with the circuit board 53 located at the maximum diameter and a window 54a through which the lens 52a of the infrared sensor 52 can be seen.

55 is a shutter made of a metal plate. The shutter 55 closes the observation window 44a, which will be described later, when the infrared sensor 52 is not in use. In order to prevent the temperature of the heating chamber 28 from being transmitted to the unit case 54, the shutter 55 is arranged to form an air passage 55c with gaps along the outer periphery of the unit case 54 so that cooling air can flow around the outer periphery of the unit case 54, and

openings

55a and 55b are provided in the air passage 55c as an entrance and exit for the cooling air 39 to flow.

Reference numeral 56 denotes a positioning protrusion, and when the control unit 23a controls the rotation of the motor 51 so that the detection point of the infrared sensor 52 is aligned with the reference position (detection point a in FIG. 4), the reference position of the detection point of the infrared sensor 52 can be corrected by making the rotation shaft 51a slip with the positioning protrusion 56 abutting against a stopper (not shown) provided on the infrared case 48 when the observation window 44a is closed by the shutter 55, and the reference position controlled by the control unit 23a and the position of the detection point a which is the reference position detected by the infrared sensor 52 can be corrected. Reference numeral 44 denotes an arc-shaped observation unit protruding inwardly of the heating chamber 28, and the rotation center of the rotation shaft 51a, the center of the cylindrical unit case 54, the center of the arc of the shutter 55 which is provided along the outer periphery of the unit case 54 and bent into an arc, and the center positions of the arc-shaped observation unit 44 are all in the same position. Reference numeral 44a denotes an observation window provided in the observation unit 44, and opens a range which is the field of view detected by the infrared sensor 52.

By protruding the observation section 44 into the inside of the heating chamber 28, it is possible to detect temperatures over a wide range with a minimum narrow observation window opening range.

49 is a convex portion that separates the infrared case 48 and the infrared unit 50 from the heating chamber top surface 28c. By having only the convex portion 49 come into contact with the heating chamber top surface 28c, the temperature of the heating chamber top surface 28c heated by heaters such as the grill heating section 12 and the hot air unit 11 during heating is less likely to be transmitted to the infrared unit 50.

102 is an outside temperature sensor arranged on the substrate 53 inside the infrared unit 50, which detects the outside temperature To outside the heating chamber 28. When multiple heated objects are heated continuously, the outside temperature To measured before the first heating starts is approximately equal to the room temperature outside the cooking device, and the outside temperature To measured before the second or subsequent heating starts is higher than the room temperature outside the cooking device but lower than the inside temperature Ti.

The measurement method of the infrared sensor 52 of the control unit 23a mounted on the control board 23 is explained with reference to FIG. 4.

Figure 4 is a diagram explaining the operation of the infrared sensor when rice is placed in a bowl and heated. As shown in Figure 4, the surface of the heated object 60c can be directly detected at detection point f.

The infrared sensor 52 measures eight points at a time, and is rotated 14 times by three degrees by the motor 51 from the reference position (detection point a in Figure 4) to the end position (detection point h in Figure 4), measuring a total of 15 rows, detecting the temperature of 120 points (8 points in the left-right direction x 15 rows in the front-back direction).The infrared sensor 52 then returns directly to the reference position without taking any measurements from the end position to the reference position.

The temperature is detected by moving the infrared sensor 52 from the reference position to the end position by 3 degrees 14 times, measuring in 15 rows, and then repeating the process of returning from the end position to the reference position. The processing of the measured temperature will be described later.

Next, we will explain the rotational movement of the infrared sensor 52.

As shown in Figure 4, when a bowl containing the object to be heated (rice) 60c is placed on the table plate 24 provided on the bottom surface 28a of the heat chamber and heating is started, the control unit 23a controls the rotating shaft 51a of the motor 51 to rotate to the reference position. When the rotating shaft 51a rotates to the reference position, the unit case 54 rotates, and the lens part 52a of the infrared sensor 52 also rotates to a position where it can detect the detection point a at the reference position (see Figure 4).

By rotating the unit case 54, the detection of the temperature of the heated object 60c progresses from the reference position (detection point a) described above to detection point b and detection point c on the table plate 24, and as the unit case 54 rotates further, the temperature of the outside of the bowl (container 60) is detected in the height direction, and the temperature is detected from detection point d to detection point e. After the detection point reaches the top of the opening of the bowl (container 60), the temperature of the surface of the heated object 60c is detected at detection point f, then the temperature of the inside of the bowl (container 60) is detected at detection point g, and then the temperature of the table plate 24 is detected at detection point h.

The temperature detection range from detection point a to detection point h is detected on one side of the forward path of the rotation of the unit case 54, and once the temperature detection is completed to the end point, no measurements or temperature detection is performed on the return path, and the temperature detection is repeated again from detection point a to detection point h in sequence after returning to the reference position.

The number of temperature detections can be changed as desired, and the aforementioned detection points a to h are illustrative examples, measuring 15 columns of data as described above.

In addition, the motor 51 stops rotating while the temperature is being detected, and then resumes rotating after the temperature is detected. To detect the temperature accurately, it is better to measure with the rotation stopped.

For example, at the beginning of heating, the rotation of the unit case 54 is stopped and detected, then rotated at a fixed angle after detection, stopped and detected, then rotated at a fixed angle after detection, and this process is repeated to measure the temperature distribution in a grid pattern. By doing so, the temperature is measured at fixed positions at equal angles, and the entire surface of the table plate 24 is measured evenly.

The infrared sensor 52 is located approximately in the center in the left-right direction of the heating chamber top surface 28c inside an imaginary line extending perpendicularly from the four sides of the table plate 24 placed on the heating chamber bottom surface 28a to the heating chamber top surface 28c.

The field of view of the infrared sensor 52, detection points a and h, is approximately set to a range for detecting the temperature of the front and rear flange portions of the table plate 24, and the sensors on both sides of the aligned multiple elements of the infrared sensor 52 are approximately set to a range for detecting the temperature of the left and right flange portions of the table plate 24. This makes it possible to accurately detect the temperature of the heated object 60c placed approximately in the center of the table plate 24. Also, it is better to rotate the infrared sensor 52 in the direction with a wider temperature measurement range in order to detect the temperature of the heated object 60c placed in the container 60.

With this setting, when the container 60 is placed at the back of the table plate 24, the temperature of the heated object 60c in the bowl can be detected at detection point b, which is approximately below the infrared sensor 52. When the container 60 is placed on one of the left and right sides of the table plate 24, the infrared sensor 52 is located approximately in the center of the heating chamber 28 in the left-right direction, so the infrared sensors on both sides of the eight elements aligned in a row in the infrared sensor 52 can detect the temperature of the heated object 60c.

Furthermore, when the weight information from the weight sensor 25 and the temperature distribution information detected by the infrared sensor 52 show that the weight information is light and the temperature distribution shows a wide range of temperature rise, it can be determined that the heated object 60c is thin and wide.

In this embodiment, a method for detecting the temperature of the heated object 60c placed in the container 60 has been described in detail, but even if the heated object 60c is a large block-shaped lump without using a container, the temperature of the side height direction and the top surface of the block-shaped heated object 60c can be detected, making it possible to detect the temperature distribution of the heated object 60c in detail.

<Flowchart of Microwave Heating Control>
Next, the range heating control by the cooking device of this embodiment will be described with reference to the flow chart of FIG.

First, in step S1, the user opens the door 2 of the heating chamber 28, places the container 60 containing the object to be heated 60c on the table plate 24, and then closes the door 2. Then, the user selects an auto menu using the input unit 71.

Next, in step S2, the user adjusts the cooking finish using the input unit 71. Specifically, from the finish adjustment K prepared in advance, the user selects one of "strong," "slightly strong," "medium," "slightly weak," or "weak." Here, the finish adjustment K "medium" results in a finish at the standard temperature, "strong" results in a finish with a higher finish temperature, and "weak" results in a finish with a lower finish temperature.

In step S3, the user presses the start button on the input unit 71.

In step S4, the weight sensor 25 detects the total weight W of the object to be heated 60c and the container 60 placed on the table plate 24.

In step S5, the internal temperature sensor 80 detects the internal temperature Ti.

In step S6, the control unit 23a determines whether the internal temperature Ti is higher than a predetermined temperature. If the internal temperature Ti is higher than the predetermined temperature, the control unit 23a transitions to the high temperature internal mode and heats the object to be heated 60c. On the other hand, if the internal temperature Ti is not higher than the predetermined temperature, the control unit 23a proceeds to step S7.

Here, the high temperature inside mode is a mode in which microwave heating is performed without using the infrared sensor 52, because when the temperature of the heating chamber 28 is high, such as immediately after oven cooking, the infrared sensor 52 cannot accurately detect the temperature of the heated object 60c. Therefore, in this mode, the user is prompted to select via the input unit 71 whether the stored state of the heated object 60c is room temperature/refrigerated or frozen, and based on this selection result and the detected weight W, the total heating time is calculated based on the results of a prior check of the heating time required to heat the heated object 60c to the input temperature, and then heating is performed.

In step S7, the infrared sensor 52 detects the temperature of each part of the top surface of the table plate.

In step S8, the control unit 23a determines whether the previous heating operation recorded in the recording unit 100 was microwave heating. If the previous heating operation was microwave heating, the process proceeds to step S10; if not, the process proceeds to step S9.

In step S9, the control unit 23a first detects the lowest temperature of the temperature of the top surface of the table plate measured by the infrared sensor 52 as the initial temperature Ts of the heated object 60c. Next, the control unit 23a classifies the storage state of the heated object 60c into "frozen," "refrigerated," or "room temperature" based on the initial temperature Ts. After that, heating and cooking are performed in the normal heating mode according to the classified state of the heated object 60c. Note that the normal heating mode is a heating mode that is selected when the infrared sensor 52 can correctly detect the temperature of the heated object 60c, and heating is terminated when the temperature of the heated object 60c reaches the desired cooking end temperature, as in conventional heating control.

In step S10, the timer 101 detects the time that has elapsed since the end of the previous heating operation until the user presses the start button (step S3), i.e., the time that has elapsed since the end of the previous heating operation until the start of the current heating operation.

In step S11, the control unit 23a judges whether the length of time detected in step S10 is shorter than a predetermined time. If the time since the previous heating ended is a long time, for example, several hours, it is judged that there are no traces on the table plate of other heated objects having been cooked in the microwave immediately prior to this microwave cooking, and the process proceeds to step S9. On the other hand, if the time since the previous heating ended is a short time, for example, several minutes, it is judged that there may be traces on the table plate of other heated objects having been cooked in the microwave immediately prior, and the process proceeds to step S12.

In step S12, the control unit 23a determines whether the maximum temperature of the temperatures of the top surface of the table plate measured by the infrared sensor 52 is higher than the temperature outside the cabinet To measured by the outside temperature sensor 102 plus a predetermined temperature. If the maximum temperature is high, it is determined that there are traces of the table plate having been previously cooked in the microwave with another heated object, and the process proceeds to step S13; if not, the process proceeds to step S9. If the top surface of the table plate is determined to be locally high in this step, it can be estimated that another microwave cooking was performed immediately before the current microwave cooking, and as a result, the top surface of the table plate has become locally high in temperature due to the heat of the previously heated heated object.

In step S13, first, the control unit 23a detects the minimum temperature among the temperatures of the top surface of the table plate measured by the infrared sensor 52 as the initial temperature Ts of the object to be heated 60c. Next, the control unit 23a classifies the storage state of the object to be heated 60c into either "frozen" or "not frozen" depending on whether the initial temperature Ts is equal to or lower than a predetermined temperature (e.g., -10°C).
Thereafter, cooking is carried out in the high temperature placement mode according to the state of the classified object 60c to be heated.

The high temperature placement mode is a heating mode in which, when there is evidence that another heated object 60c had been cooked in the microwave immediately prior to this microwave cooking (the table plate is locally hot) and these evidences may cause the infrared sensor 52 to misinterpret the temperature of the heated object 60c, the microwave heating time is calculated to heat the heated object 60c to an appropriate temperature according to the weight W detected in step S4 and the storage state determined in step S13.

Here, using Figure 8, microwave heating when the high temperature placement mode is selected is explained. When the high temperature placement mode is selected, the total heating time is the sum of the sensing time t1 in the first stage and the microwave heating time t2 in the second stage. The sensing time t1 in the first stage is the period for performing the sensing process, during which the weight W and storage state of the heated object 60c are obtained. Meanwhile, the microwave heating time t2 in the second stage is calculated using one of the formulas below, based on the weight W and storage state of the heated object 60c obtained by sensing.

<When the object to be heated is frozen>
t2a= _k1 ×( _k2 - _k3 ×Ts)×W...(Formula 1)
<If the item to be heated is not frozen (refrigerated, room temperature)>
t2b=k ₁ × (k ₄ - _{k 5} ×Ts) × W (Formula 2)
Here, _k1 is a coefficient according to the setting of finish adjustment K, for example, 1.5 for the "strong" setting, 1.2 for the "slightly strong" setting, 1 for the "medium" setting, 0.8 for the "slightly weak" setting, and 0.5 for the "weak" setting. Also, _k2 to _k5 are predetermined positive numbers, and are set to values that always make t2a in formula 1 and t2b in formula 2 positive when the initial temperature Ts of the heated object is equal to or lower than the cooking completion temperature.

As a result, as long as the storage state of the heated object 60c can be classified as "frozen" or "not frozen," even if the temperature of the heated object 60c cannot be accurately measured due to traces of previous microwave heating, the microwave heating time t2 required to heat the heated object 60c to the appropriate temperature can be calculated, and the heated object 60c can be heated to the appropriate temperature by using the microwave heating time t2.

As described above, with the high-frequency cooking device of this embodiment, when multiple objects to be heated are successively cooked, the objects to be heated this time can be heated to an appropriate temperature even if the temperature of the place where the objects to be heated are placed has risen during the previous heating.

1. The main body of the cooking device,
23a control unit,
24 table plate,
25 weight sensor,
28 heating chamber,
33 magnetron,
52 infrared sensor,
60 containers,
60c object to be heated,
71 input unit,
80 Internal temperature sensor,
100 Recording unit 101 Timer 102 Outside temperature sensor
Ti: temperature inside the chamber;
To outside temperature,
Ts Initial temperature of the heated object

Claims

a heating chamber housing a table plate;
A range heating unit that heats an object to be heated placed on the table plate;
an infrared sensor for detecting the temperature at a plurality of points on the top surface of the table plate;
An outside temperature sensor for detecting an outside temperature of the heating chamber;
A recording unit for recording the previous heating operation;
A timer that measures the elapsed time from the end of the previous heating operation to the start of the current heating operation;
A control unit that controls the range heating unit,
The control unit
When the previous heating operation recorded in the recording unit was a microwave oven heating operation, the time measured by the timer is shorter than a predetermined time, and the maximum temperature of the temperature of the top surface of the table plate detected by the infrared sensor is higher than a predetermined temperature,
A high-frequency heating cooker characterized in that the state of the heated object is classified as frozen or not based on the initial temperature of the heated object detected by the infrared sensor, a heating time according to the classified state is calculated, and the range heating section is controlled.
The high frequency heating cooker according to claim 1,
Further, a weight sensor is provided to detect the weight of the object to be heated,
The high frequency heating cooker, wherein the control unit calculates a heating time according to the weight and controls the microwave heating unit.