JP2013097936A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating cooker capable of precisely detecting a temperature of a pan.SOLUTION: The induction heating cooker includes an infrared sensor 17 provided below a top plate 2 and detecting a temperature of a pan 30, a thermistor 15 detecting a temperature of a pan bottom of the pan 30 through the top plate 2, an operation section 7 for setting a set temperature at which the pan 30 is heated, and control means 118 of performing temperature adjustment by controlling inverter means 100 using the infrared sensor 17 and the thermistor 15 so that the temperature of the pan 30 reaches the set temperature. When a heating temperature of oil is set at the operation part 7 so as to cook a fry, the control means 118 uses the infrared sensor 17 for temperature adjustment on the pan 30 and carries out heating before at least the temperature of the oil reaches the set temperature and preheating is completed, and then uses the thermistor 15 to perform temperature adjustment on the pan 30.

Description

  The present invention relates to an induction heating cooker provided with a temperature sensor that detects the temperature of a pan through a top plate.

  There is an induction heating cooker described in Patent Document 1 that detects the temperature of a pan placed on a top plate by a temperature detector (temperature sensor) configured by a thermistor provided in close contact with the lower surface of the top plate.

  Moreover, there exists the induction heating cooking appliance of patent document 2 which detects the infrared rays radiated | emitted from a pan bottom using an infrared sensor, and calculates temperature.

JP 2009-26571 A JP 2009-259608 A

  The induction heating cooker of patent document 1 detects the temperature of a pan with the temperature detector comprised with the thermistor closely_contact | adhered to the lower surface of the top plate. The path through which the temperature of the pan is transmitted to the temperature detector is transmitted to the bottom of the pan, the recessed space of the pan bottom, and the top plate, and finally to the temperature detector. Therefore, there exists a subject that time delay arises in detecting the temperature change of a pan. Moreover, there exists a subject that the said time delay changes according to the magnitude | size of the dent of a pan bottom. Furthermore, even if the temperature of the pan is adjusted at the same control temperature according to the size of the recess at the bottom of the pan, there is a problem that the temperature of the pan differs.

  In particular, when preheating to heat oil to a set temperature during cooking of deep-fried food, there is a large time difference between the actual oil temperature rise and the temperature rise observed by the temperature detector composed of the thermistor. As a result, heating continues even though the oil temperature reaches the set temperature, and a problem occurs that causes an overshoot in which the oil temperature rises above the set temperature. In addition, since overshoot occurs, it takes time for the oil temperature to stabilize at the set temperature, causing a problem that notification of the end of preheating is delayed.

  Moreover, in the induction heating cooking appliance of patent document 2, it is possible to detect the temperature of a pan bottom with an infrared sensor accurately, and the pan bottom can be efficiently heated with a large heating power by induction heating. However, when food is put into oil when cooking fried food, the infrared sensor detects a decrease in oil temperature, and when the heating power of the heating coil is increased based on this, the temperature at the bottom of the pan rises rapidly. And since the output of the heating coil which the infrared sensor detects the temperature rise and is heating directly is reduced, there exists a subject that the temperature rise of the whole oil becomes late as a result.

  An induction heating cooker according to the present invention is made to solve the above-described problems, and includes a top plate on which a pan is placed, a heating coil provided below the top plate, and a lower side of the top plate. A first temperature sensor that receives infrared rays emitted from the pan bottom of the pan and detects the temperature of the pan bottom; and a temperature of the pan bottom of the pan through the top plate that is provided below the top plate A second temperature sensor composed of a thermistor for detecting the temperature, inverter means for supplying electric power to the heating coil, an operation unit for setting a set temperature for heating the pan, the first temperature sensor, and the first Control means for adjusting the temperature by controlling the inverter means so that the temperature of the pan becomes the set temperature using a second temperature sensor, and the control means also fries at the operation unit. When the heating temperature of the oil is set for cooking, etc., the first temperature adjustment of the pan is performed at least until the temperature of the oil reaches the set temperature and the preheating is completed. Heating is performed using a temperature sensor, and then the temperature of the pan is adjusted using the second temperature sensor constituted by a thermistor.

  According to the induction heating cooker of the present invention, when preheating oil used for fried food, since the temperature rise of the pan bottom is detected using an infrared sensor, the temperature of the pan bottom that rises following the actual oil temperature rise is detected. Can detect temperature. Therefore, an excessive overshoot with respect to the set temperature for heating the pan is not caused, and the time spent until the end of preheating can be reduced accordingly.

  Moreover, when the food is fried, the temperature of the pan is adjusted by a temperature sensor composed of a thermistor, so that there is no difference between the temperature of the pan bottom and the oil temperature, and a good fried food can be cooked.

The external appearance perspective view of the induction heating cooking appliance of one Example. The top view except the top plate of the induction heating cooking appliance of one Example. The block diagram which mainly made the right and left heating coils of the induction heating cooking appliance of one Example. The figure explaining a reflection type photo interrupter. The figure explaining the upper surface operation part and upper surface display part of the induction heating cooking appliance of one Example. The block diagram of the inverter means of the induction heating cooking appliance of one Example. The flowchart explaining operation | movement of the induction heating cooking appliance of one Example. The flowchart explaining the preheating process of the induction heating cooking appliance of one Example. The flowchart explaining the cooking process of the induction heating cooking appliance of one Example.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is an external perspective view of an induction heating cooker according to an embodiment. In FIG. 1, the top plate 2 is horizontally arrange | positioned on the upper surface of the main body 1 of the induction heating cooking appliance. The top plate 2 is made of crystallized glass with a high heat resistance and has a thickness of about 4 mm, and the pan 30 is placed thereon. Below the top plate 2, the annular heating coils 3 are arranged on the left and right sides of the upper part in the main body 1 and the central rear part, respectively, and the induction heating is performed on the pan 30 and the like placed on the top plate 2. On the front side upper surface of the top plate 2, upper surface operation units 7 a, 7 b, 7 c (operation unit 7) are provided as operation units for setting the heating conditions of the pot 30 corresponding to each heating coil 3. 3 is set for energization. Corresponding to the upper surface operation parts 7a, 7b and 7c, upper surface display parts 8a, 8b and 8c are provided in the vicinity of the upper surface operation parts 7a, 7b and 7c, and the energization state of each heating coil 3 is determined. indicate. The upper surface operation unit 7a inputs the heating power of the heating coil 3 on the right side of the main body 1, the upper surface operation unit 7b inputs the heating power of the heating coil 3 at the center rear of the main body 1, and the upper surface operation unit 7c is on the left side of the main body 1. The heating power of the heating coil 3 is input.

  An intake port 4 that opens upward is provided on the right side of the rear portion of the main body 1, and cooling air sucked from the intake port 4 by a fan (not shown) provided in the main body 1 is introduced into the main body 1. It cools by flowing in the control board (not shown), the heating coil 3, etc. which were provided. An exhaust port 5 for exhausting the cooling air that has cooled the inside of the main body 1 is provided on the rear left side of the main body 1.

  A grill heating means 6 for grilling fish, pizza or the like is provided on the left side of the front surface of the main body 1, and the grill heating means 6 has a box shape with an open front, and a sheathed heater or the like in an internal cooking chamber. The thermistor for detecting the temperature of the heating element and the internal temperature are provided, and the front surface is closed by a grill door 6b to which a handle 6a is attached. The grill door 6b has a saucer attached to the back side of the grill door 6b. The grill door 6b is housed in the cooking chamber so that it can be inserted and removed freely from the front opening, and cooked by placing ingredients such as fish and pizza on the grill net placed on the saucer. To do.

  A main power switch 9 for supplying power to the main body 1 and a front operation unit 10 for inputting cooking conditions for the grill heating means 6 and the like are provided on the right front portion of the main body 1. The front operation unit 10 has a so-called kangaroo pocket shape in which the upper part of the operation panel 11 is tilted to the front side around a rotation axis provided below and the operation keys 12 are exposed upward.

  FIG. 2 is a top view of the induction heating cooker excluding the top plate 2, and FIG. 3 is a block diagram showing a configuration mainly including the left and right heating coils 3 of the induction heating cooker. The heating coils 3 arranged at the left and right and the central rear part are each composed of an annular inner heating coil 3a and an annular outer heating coil 3c arranged with an annular gap 3b on the outside thereof. The reason why the gap 3b is provided in the heating coil 3 is to disperse the magnetic flux generated by the inner heating coil 3a and the outer heating coil 3c and to make the temperature of the pan 30 uniform. In addition, although each heating coil 3 was set as the structure which provides the clearance gap 3b, it is not limited to this in particular. For example, the structure which is set as the heating coil 3 without the gap | interval 3b which wound the inner side heating coil 3a and the outer side heating coil 3c without the gap may be sufficient.

  As shown in FIG. 3, the heating coil 3 is installed on a coil base 13. A gap spacer 14 is provided at appropriate intervals from the outer periphery of the coil base 13 toward the center by a support member 16 attached to the outer peripheral edge of the coil base 13, and the coil base 13 includes a plurality of coil bases 13. By being biased in the direction of the top plate 2 by a spring (not shown), the heating coil 3 is substantially parallel to the top plate 2, and the pot 30 and the heating coil 3 placed on the top plate 2 are The gap is kept constant.

  The heating coil 3 employs a litz wire to suppress the skin effect, and a voltage of several hundred volts is applied at a high frequency of several tens kHz by the inverter means 100 described later, and a high frequency magnetic field is applied to the pan 30. An eddy current is generated in the pan 30 and the pan 30 is heated by self-heating.

  A plurality of temperature sensors 15 composed of thermistors are provided in the vicinity of the center of the heating coil 3 disposed on the left and right, and one of the temperature sensors 15 a is provided in close contact with the lower surface of the top plate 2. The temperature of the pan 30 placed above the heating coil 3 is detected via the top plate 2 (by heat conduction). Similarly, the gap 3b of the heating coil 3 is provided with outer temperature sensors 15b, 15c, 15d composed of thermistors at equal distances from the center of the heating coil 3 and at equal intervals of 120 degrees. 15b, 15c, and 15d are provided on the gap spacer 14 on a cushioning material (not shown) and are in close contact with the lower surface of the top plate 2 to detect the temperature of the pan 30 placed above the heating coil 3.

  The temperature sensor 15 composed of a thermistor detects the temperature transmitted by heat conduction and changes the resistance of the thermistor itself. The temperature is confirmed in advance by capturing the resistance change by the control means 118 described later. The temperature detected by the temperature sensor 15 is calculated from the relationship between the resistance value and the resistance value.

  Below the gap 3b of the heating coil 3 arranged on the left and right, an infrared sensor 17 is provided that receives infrared rays emitted from the bottom surface of the pan 30 through the top plate 2 and detects the temperature from the received infrared energy. It has been. The infrared sensor 17 is a temperature sensor using a thermal detection element, and its light receiving surface 17a is located at a position near the center of the inner heating coil 3a and about 35 mm from the lower surface of the top plate 2 below the heating coil 3. It is provided at a remote location. Then, a voltage corresponding to the amount of received infrared light is output, and the control means 118 (to be described later) amplifies the output voltage and determines the detected temperature of the infrared sensor 17 from the relationship between the voltage amount and the temperature confirmed in advance. Is to be calculated. Further, the light receiving surface 17a is provided with a lens, a light guide tube, and the like (not shown) that limit the viewing angle of infrared rays to be detected. As shown in FIG. The viewing angle is detected by the detection spot 17b.

  A reflective photo interrupter 18 is provided at a position away from the lower surface of the top plate 2 in the gap 3b between the heating coils 3 arranged on the left and right. FIG. 4 is a diagram for explaining the reflective photointerrupter 18. As shown in the drawing, the reflection type photointerrupter 18 has an infrared LED 18a as an infrared light emitting means and an infrared phototransistor 18b as an infrared light receiving means arranged on the same plastic member and molded 18c. A plastic lens is formed on the light emitting surface of the infrared LED 18a, and irradiates a thin beam of infrared light upward. A visible light blocking plastic lens is formed on the light receiving surface of the infrared phototransistor 18b, and the reflected infrared light at the object (pan bottom) of the irradiated infrared light is received with a narrow viewing angle, and the amount of received light. A current proportional to is output. Here, the reflection type photo interrupter 18 is provided at a position away from the infrared sensor 17, but the reflection type photo interrupter 18 and the infrared sensor 17 may be provided close to each other. May be.

  From the output of the infrared phototransistor 18 b of the reflection type photointerrupter 18, the reflectance of the bottom surface of the pan 30 placed on the top plate 2 is measured by the reflectance measuring means 19 and input to the control means 118. The control means 118 calculates the temperature of the pan 30 by correcting the value output from the infrared sensor 17 using this reflectance.

  FIG. 5 is a diagram illustrating the upper surface operation unit 7a and the upper surface display unit 8a. Since the contents of the upper surface operation unit 7c and the upper surface display unit 8c are the same as the contents of the upper surface operation unit 7a and the upper surface display unit 8a, the description thereof is omitted.

  Reference numeral 74 denotes a cut / start key for starting or stopping cooking. The thermal power setting means 72 is divided into four keys, a “hot fire” key 72a, a “low fire” key 72b, a “medium fire” key 72c, and a “high fire” key 72d, and the necessary thermal power can be input by one operation. The arrow adjusting means 73 is used when the thermal power is finely adjusted up and down or set temperature is changed after the thermal power setting means 72 is set. The menu setting means 71 is for setting “cooking rice”, “fried food”, “boiled water”, “stir fried food”, “steak”, etc. for automatic cooking. A menu is displayed at 81a, and the menu is switched and displayed each time the menu setting means 71 is pressed. This selects the menu to be used.

  The upper surface display unit 8a is divided into a display unit 81a and a display unit 81b, and the display unit 81a displays the thermal power input by the thermal power setting means 72, the cooking menu input by the menu setting means 71, and the like. The display unit 81b informs the user of the timing of loading the ingredients when the pan 30 is preheated and the temperature of the pan 30 reaches an appropriate temperature in the “fried food” or “steak” menu set by the menu setting means 71. “Preheating” and “Appropriate temperature” can be displayed so as to be able to.

  When “fried food” is selected by the menu setting means 71, it is necessary to set the oil temperature next, and the arrow adjusting means 73 can be operated to set six set temperatures from 150 ° C. to 200 ° C. For example, when fried food is set by the menu setting means 71 and then the oil temperature is set to 180 ° C. by the arrow adjusting means 73, the display unit 81a displays the number “180” and “fried food” as shown in FIG. Is displayed.

  FIG. 6 is a block diagram of the inverter means 100. The heating control of the pot 30 by the left and right heating coils 3 will be described with reference to the block diagrams of FIGS. Note that the control of the grill heating unit 6 and the control of the heating coil 3 at the center rear of the main body 1 are not directly related to the present embodiment, and thus the description thereof is omitted.

  The control means 118 includes outputs from the menu setting means 71 and the thermal power setting means 72 of the upper surface operation unit 7a, an inner temperature sensor 15a, outer temperature sensors 15b, 15c and 15d provided near the heating coil 3, an infrared sensor 17, and a reflection. The output of the rate measuring means 19 is input. In addition, the control means 118 adjusts the temperature of the pan 30 to the set temperature set by the upper surface operation unit 7a and heats the pot 30 corresponding to the set temperature, and each of the temperature sensors 15a, 15b, 15c, 15d and the infrared sensor. The control temperature which controls the inverter means 100 based on the detected temperature of 17 is provided. Further, the reason for providing the plurality of temperature sensors 15a, 15b, 15c, 15d and the infrared sensor 17 is to prevent the temperature detection accuracy from being lowered due to deformation of the pan bottom when detecting the temperature of the pan 30.

  As shown in FIG. 6, the inverter unit 100 is configured such that an AC power source 117 is converted into a DC voltage by the rectifying unit 102 and connected to a switching unit configured by a series body of switching elements 103 and 105. Diodes 104 and 106 are connected in antiparallel to the switching elements 103 and 105, respectively, and a resonance circuit unit composed of the heating coil 3 and the resonance capacitor 107 is connected between the connection point of the switching elements 103 and 105 and the reference point of the DC voltage. To do. Snubber capacitors 108 and 109 are connected to the switching elements 103 and 105, respectively. By turning on and off these switching elements 103 and 105 exclusively at high frequency, a high frequency resonance current is supplied to the resonance circuit section composed of the heating coil 3 and the resonance capacitor 107, and a load arranged in the vicinity of the heating coil 3 is heated. To do.

  The control unit 110 of the inverter unit 100 inputs a target power level instruction to be applied to the load from the control unit 118, and controls the switching units 103 and 105 so that the output power of the inverter unit 100 becomes a target value.

  The input current conversion unit 112 converts the output signal of the detection unit 111 that detects the current input from the AC power source 117 to an appropriate level and outputs the converted signal to the control unit 110. The input voltage detection means 113 detects the voltage of the AC power supply 117, converts it to an appropriate level, and outputs it to the control unit 110. The inverter current detection means 115 converts the output signal of the detection means 114 that detects the current flowing through the resonance circuit section into an appropriate level and outputs it to the control section 110.

  The controller 110 inputs these signals, calculates inverter power that is input to the load, determines the state of the load, suitability for heating, etc., and exclusively controls the switching elements 103 and 105 to be turned on and off. A signal is output, and the level conversion unit 116 converts the switching elements 103 and 105 to an appropriate driving level to drive the switching elements 103 and 105. The control unit 110 outputs these states to the control unit 118.

  In the induction heating cooker configured as described above, the flowchart of FIG. 7 is used when the user cooks “fried food” to perform tempura cooking using oil using the heating coil 3 on the right side of the main body 1. Each process will be described using this method.

  The first step S1 is a standby step waiting for the main power switch 9 of the main body 1 to be turned on. When the main power switch 9 is turned on, the process proceeds to the next step. Moreover, the pan 30 filled with oil before and after this step is placed in the center of the heating coil 3 on the right side of the main body 1.

  Step S <b> 2 is a menu setting step for setting a heating method for the pot 30. In this step, the thermal power is input by the thermal power setting means 72 or an automatic cooking menu is set by the menu setting means 71. Here, the menu setting means 71 of the upper surface operation unit 7a is operated while viewing the display unit 81a to select “fried food”. In step S3, it is determined whether “fried food” is selected. If “fried food” is not selected, the process proceeds to step S4. If “fried food” is selected, the process proceeds to step S5. In addition, since a present Example is related to "fried food" cooking, description is abbreviate | omitted about process S4 when not selecting "fried food" cooking.

  Step S <b> 5 is a temperature setting step of setting the oil heating temperature by operating the arrow adjustment key 73, and the set temperature that is the oil heating temperature is set using the arrow adjustment key 73. Although the oil temperature suitable for cooking fried food varies depending on the food to be fried, it is often cooked at a temperature of about 150 to 200 ° C. Here, the set temperature is set to 180 ° C. suitable for making tempura such as shrimp, pumpkin, and salmon. It is assumed that “180” is displayed on the display unit 81a (FIG. 5).

  The next step S6 is a cooking start step for waiting for the start of cooking. In this step, the input of the cut / start key 74 is waited, and when it is input, cooking of the fried food is started. In the first step of fried food cooking, a preheating step of heating the oil temperature to the set temperature is started, and “Preheating” on the display portion 81b (FIG. 5) is lit. And it progresses to the next process.

  When preheating of fried food cooking is started, the next step S7 is a reflectance measuring step for measuring the reflectance of the pan 30 used for cooking. In the reflectance measurement step, the reflectance of the pan 30 is measured from the output of the reflective photointerrupter 18 by the reflectance measuring means 19 and input to the control means 118 and used for correction when the temperature of the pan is detected by the infrared sensor 17. . The measurement may be performed only once at the beginning of heating or periodically during preheating / cooking.

  The next step S8 is a preheating step of heating the oil put in the pan 30 to the set temperature and stabilizing the oil temperature at the set temperature. In the preheating process, when the temperature sensor detects that the oil temperature has reached the set temperature and has been stabilized, “in preheating” on the display unit 81b (FIG. 5) is turned off, “appropriate temperature” is turned on, and an appropriate temperature notification is given. To inform the user of the end of preheating. When preheating ends, the process proceeds to the next cooking step. Detailed control of the preheating process will be described later.

  The next step S9 is a cooking step for cooking fried food. Detailed control of the cooking process will be described later.

  The last step S10 is a cooking end step. When the cut / start key 74 is pressed, the heating to the pan 30 ends.

  Next, the control method of preheating process S8 is demonstrated in detail using FIG. Steps S8-1 and S8-4 show the entrance and exit of the subroutine of the preheating step S8. Step S8-2 is a temperature adjustment step of adjusting the temperature of the pan 30 to the set temperature. An infrared sensor 17 is used as a temperature sensor used to detect the temperature of the pan 30 and adjust the temperature in this temperature adjustment step. An infrared sensor 17 detects the temperature at the bottom of the pan that rises following the oil temperature rise. Then, the temperature adjustment is performed in comparison with the temperature detected by the infrared sensor 17 at the control temperature for the infrared sensor 17 corresponding to the set temperature set in step S5. Step S8-3 is a step of confirming whether the temperature of the heated oil is stable. The confirmation method is a method of determining by detecting a temperature range in which the detection temperature of the infrared sensor 17 is constant for a certain time.

  And if it confirms that oil temperature was stabilized, preheating process S8 will be complete | finished and it will progress to cooking process S9. The constant temperature and time determined to be stable here are determined to be stable because the fluctuation of the temperature detected by the infrared sensor 17 is within ± 8 ° C. and continuously within the temperature range for 120 seconds. ing.

  At the same time, confirmation of whether or not the oil temperature has stabilized using the inner temperature sensor 15a is proceeding in the same manner. When a temperature range in which the temperature detected by the inner temperature sensor 15a is constant is detected for a certain period of time, the oil temperature is confirmed to be stable, the preheating step S8 is terminated, and the process proceeds to the cooking step S9. Here, the constant temperature and time determined to be stable are determined to be stable because the fluctuation of the temperature detected by the inner temperature sensor 15a is within ± 2 ° C. and remains within that temperature range for 60 seconds. ing.

  In this embodiment, when it is confirmed that the oil temperature has stabilized earlier, either the infrared sensor 17 or the inner temperature sensor 15a, the preheating step S8 is terminated, and the process proceeds to the next cooking step S9.

  Next, the control method of cooking process S9 is demonstrated in detail using FIG. Process S9-1 and process S9-8 show the entrance and exit of the subroutine of cooking process S9. Step S9-2 is a step of confirming the temperature sensor that has determined completion of preheating, and since the infrared sensor 17 and the inner temperature sensor 15a have detected that the oil temperature has stabilized in the preheating step S8, this step Then, it is a process of confirming which temperature sensor confirmed the stability of the oil temperature.

  When the oil temperature stability is confirmed by the inner temperature sensor 15a, the process proceeds to step S9-3, and when the oil temperature stability is confirmed by the infrared sensor 17, the process proceeds to step S9-4.

  Step S9-3 is a step of correcting the control temperature provided for the inner temperature sensor 15a with respect to the set temperature. Here, it is a step of replacing the detected temperature detected when the oil temperature is determined to be stable in the preheating step S8 with the control temperature provided for the inner temperature sensor 15a. By replacing, even if the inner temperature sensor 15a is used, the temperature can be adjusted at an oil temperature that is substantially the same as the oil temperature when the temperature is adjusted by the infrared sensor 17 at the control temperature for the infrared sensor 17. Therefore, the temperature detected by the inner temperature sensor 15a while the temperature is adjusted by the infrared sensor 17 is changed to the control temperature provided for the inner temperature sensor 15a in the pan currently used for cooking. Therefore, the difference in temperature that occurs depending on the condition of the pan bottom, etc. does not occur.

  Step S9-4 is a step that passes when oil temperature stability is confirmed by the infrared sensor 17 in the preheating step S8. Therefore, the temperature adjustment of the pan 30 is continued using the infrared sensor 17 after the cooking process S9 is started.

  Step S9-5 is a step of detecting the start of cooking. Since the end of preheating has already been notified, it is expected that the user will always put food into the oil in the pan 30. Thus, the temperature of the pan bottom is detected using the inner temperature sensor 15a, and it is determined that cooking is started when the detected temperature detects a temperature drop of a certain temperature or more within a certain time. When it is determined that cooking has started, the process proceeds to the next step S9-6. The condition for determining that cooking has been started is when the inner temperature sensor 15a detects a temperature drop of 2 ° C. or more in 15 seconds. Moreover, when the rapid temperature change of the pan bottom seen as the start of cooking is not seen, it progresses to the following process S9-7.

  In step S9-6, the temperature immediately before detecting the temperature drop by the inner temperature sensor 15a in step S9-5 is corrected to the control temperature provided for the inner temperature sensor 15a, and used for temperature adjustment of the pan 30. This is a step of changing the temperature sensor to be changed from the infrared sensor 17 to the inner temperature sensor 15a.

  Step S9-7 is a step of correcting the control temperature provided for the inner temperature sensor 15a by confirming the stability of the oil temperature by the inner temperature sensor 15a. In this step, the condition for completing the correction is that the fluctuation of the detected temperature of the inner temperature sensor 15a is within ± 2 ° C., and the detected temperature is kept within that temperature for 60 seconds. This is a process of correcting the control temperature and changing the temperature sensor used for adjusting the temperature of the pan 30 from the infrared sensor 17 to the inner temperature sensor 15a.

  Step S9-8 is a step of adjusting the temperature of the pan 30 using the inner temperature sensor 15a with the corrected control temperature. Note that the temperature sensor 15 configured as a thermistor used for temperature adjustment is not limited to the inner temperature sensor 15a. Other temperature sensors (15b, 15c, 15d) may be used. The correction is the same. When the pan 30 is heated, temperature sensors other than the temperature sensor used for temperature adjustment always detect the temperature of the pan 30 as a backup, and monitor whether the temperature of the pan 30 is normal. ing. In this step S9-9, the infrared sensor 17 and the temperature sensors (15b, 15c, 15d) always detect the temperature of the pan 30 as a backup of the inner temperature sensor 15a, and monitor whether the temperature of the pan 30 is normal. ing. Furthermore, since the control temperature of the inner temperature sensor 15a is corrected with respect to the pot used every time cooking is performed, the temperature of the pot 30 can always be detected accurately.

  According to the above-described embodiment, when preheating oil used for deep-fried food, an infrared sensor is used to detect the temperature rise at the bottom of the pan. It can be detected. Therefore, an excessive overshoot with respect to the set temperature for heating the pan is not caused, and the time spent until the end of preheating can be reduced accordingly.

  Moreover, when the food is fried, the temperature of the pan is adjusted by a temperature sensor constituted by a thermistor, so that there is no difference between the temperature of the pan bottom and the oil, and a good fried food can be cooked.

2 Top plate 3 Heating coil 15 Temperature sensor 17 Infrared sensor 18a Infrared LED
18b Infrared phototransistor 19 Reflectivity measuring means 71 Menu setting means 118 Control means

Claims (1)

A top plate on which the pan is placed, a heating coil provided below the top plate, and infrared rays emitted from the pan bottom of the pan provided below the top plate to detect the temperature of the pan bottom Power is supplied to the first temperature sensor, a second temperature sensor that is provided below the top plate and that detects the temperature of the pan bottom of the pan through the top plate, and the heating coil. Inverter means, an operation unit for setting a set temperature for heating the pan, the inverter means so that the temperature of the pan becomes the set temperature using the first temperature sensor and the second temperature sensor. Control means for controlling and adjusting the temperature,
In the case where the heating temperature of the oil is set for cooking the fried food or the like in the operation unit, the control means is at least until the temperature of the oil reaches the set temperature and the preheating is completed. Heating is performed using the first temperature sensor to adjust the temperature of the pan, and then the temperature of the pan is adjusted using the second temperature sensor constituted by a thermistor. Induction heating cooker.