JP4301097B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that can perform automatic output control based on temperature information of a pan such as boiling detection control.

Conventionally, in an induction heating cooker, when controlling the heating output in accordance with information about the temperature of the pan, the temperature of the pan is controlled by a heat sensitive (heat receiving) element such as a thermistor that is in contact with the lower surface of the top plate on which the pan is placed. Some are being measured (see, for example, Patent Document 1). In addition, there is an apparatus that measures the temperature of the pan in a non-contact manner by providing an infrared transmitting portion on the top plate and detecting infrared rays from the pan with an infrared sensor (see, for example, Patent Document 2).
JP 2003-317919 A JP 2003-317918 A

  However, the material of the top plate usually used in the induction heating cooker is ceramic and has low thermal conductivity. Therefore, in the conventional temperature measurement using a thermosensitive (heat receiving) element such as a thermistor, a large temperature difference occurs between the detected temperature and the actual pan bottom temperature due to a delay in the thermal response of the top plate. Moreover, in the temperature measurement by an infrared sensor, even if the change of the pan bottom temperature can be detected, there is a problem in detecting the water temperature in the pan.

  This invention solves the said conventional subject, and it aims at providing a user-friendly induction heating cooker by detecting the boiling with high accuracy and correcting and displaying the temperature.

In order to solve the conventional problems, an induction heating cooker according to the present invention includes an inverter that supplies a high-frequency current to a heating coil that heats a pan on a top plate that transmits infrared rays, and a heating control unit that controls the inverter. Infrared detection means for detecting infrared rays radiated from the bottom of the pan and transmitted through the top plate, temperature detection means for detecting the bottom temperature of the pan from the output of the infrared detection means, and an operation unit for inputting a user's control command A water heating start key for inputting a control command for starting an automatic water heating sequence provided, a temperature display means for displaying the temperature detected by the output of the temperature detection means, and an operation of the water heating start key, When the temperature difference in the pan bottom temperature detected from the output falls within the predetermined temperature difference, boiling detection is performed to determine that the water has boiled and a signal is output to the heating control means. A detection unit, and a correcting means for previously storing an output value of the temperature detecting means at the time of boiling detected by boiling detecting means, correction means, an output value output value temperature detecting means is detecting is stored When the temperature reaches the temperature display means , the temperature display means displays 100 ° C. The output value detected by the temperature detection means is corrected by the stored output value. The temperature is displayed.

  As described above, it is possible to provide an induction heating cooker that is easy to use by performing boiling detection with high accuracy by the infrared detection means, temperature detection means, and boiling detection means, and by correcting and displaying the display temperature by the correction means.

  The induction heating cooker of the present invention is easy to use by accurately detecting boiling and correcting and displaying the display temperature.

1st invention controls the said heating coil which heats a pan, the top plate which mounts a pan on the said heating coil, and permeate | transmits infrared rays, the inverter which supplies a high frequency current to the said heating coil, and the said inverter An automatic water heater provided in a heating control means, an infrared detection means for detecting infrared rays that are placed below the top plate and emitted from the bottom of the pan and transmitted through the top plate, and an operation unit for inputting a user's control command A hot water start key for inputting the control command for starting a sequence, a temperature detecting means for detecting a pan bottom temperature from the output of the infrared detecting means, and an operation of the hot water start key, When the temperature difference between the temperature display means for displaying the detected temperature and the temperature at the bottom of the pan detected from the output of the temperature detection means is within a predetermined temperature difference, the water has boiled. Boil detecting means for performing a predetermined boiling detection and outputting a signal to the heating control means; and a correcting means for preliminarily storing an output value of the temperature detecting means when the boiling is detected by the boiling detecting means. Is detected by the temperature display means so that the temperature display means displays 100 ° C. when the output value detected by the temperature detection means becomes the stored output value. By using the induction heating cooker that displays the temperature of the water during the automatic water heating sequence operation in which the output value being corrected is corrected by the stored output value, infrared detection means, temperature detection means, and boiling detection means In addition to detecting boiling with high accuracy, the difference between the emissivity of the pan and DOO diode characteristics user display temperature obtained by correcting the difference by displaying on the temperature display means can know the temperature more in a precise pot, it is possible to provide a user-friendly induction heating cooker.

A second invention is, in particular, in the first invention, an adjustment start means provided in the operation unit for inputting an operation instruction of the user, the heating control means is initiated by the adjustment starting unit, boiled An adjustment mode for storing the output value of the temperature detection means at the time when boiling is detected by the detection means is provided , and the correction means is detected by the temperature detection means based on the output value stored in the adjustment mode by the heating control means. By correcting the output value and displaying it on the temperature display means, the temperature adjustment displayed by the temperature display means can be easily performed, and the adjustment in the manufacturing process and the repaired product can be easily performed.

According to a third invention, in particular, in the first or second invention, the infrared detecting means is constituted by a photodiode capable of detecting a wavelength of 2.5 μm or less, and the top plate is made of ceramic. Infrared light having a wavelength range that efficiently transmits through the ceramic top plate is incident on the photodiode.

In particular, in any one of the first to third inventions, the heating control means has a heating mode from the start of heating to boiling detection, and a heat retention mode for performing heat retention from boiling detection. The warming temperature in the warming mode is set by the warming temperature setting means, so that the warming temperature can be freely set to a desired temperature and is easy to use.

Embodiments and reference embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited by this embodiment and the reference form .

(Embodiment 1)
1 and 2 show an induction heating cooker according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the induction heating cooker in the present embodiment has a heating coil 3 that heats a pan 1 that contains water, and a transparent infrared ray that places the pan 1 on the heating coil 3. It has a ceramic top plate 2 that transmits through and an inverter 4 that supplies a high-frequency current to the heating coil 3. An infrared detecting means 5 for detecting infrared rays radiated from the bottom surface of the pan 1 is installed on the lower surface of the top plate 2 at the center of the heating coil 3, and a mirror-like reflecting tube 6 having an open top and high reflectivity. Surrounded. Further, the temperature detection means 7 for detecting the bottom temperature of the pan 1 from the output of the infrared detection means 5, the temperature display means 11 for displaying the temperature detected by the output of the temperature detection means 7, and the temperature detection means 7 Boiling detection means 8 that performs boiling detection according to the output and outputs a signal to the heating control means 9 that controls the inverter 4, and the temperature displayed by the temperature display means 11 from the temperature at the time of boiling detection by the boiling detection means 8 Correction means 10 for correcting

  The heating control means 9 is supplied with an output signal of the operation unit 12 having an operation switch 12a for inputting a user's control command by operation. When the operation switch 12a is operated to heat and boil the water in the pan 1, and the boiling is detected, the heating control means 9 notifies the user to that effect by a notifying means (not shown), and The heating output is suppressed for a predetermined time to perform a heat retaining operation, and the heating operation is stopped after a predetermined time has elapsed. That is, the operation switch 12a is a water heating start key for inputting a “water heating command” for starting an automatic water heating sequence.

  In addition, as shown in FIG. 2, the temperature display means 11 displays the water temperature in the pan 1 during the automatic water heating sequence operation using an LCD display element.

  The operation of the induction heating cooker having the above configuration will be described below.

  When water is put into the pan 1 and placed on the top plate 2 and the power is turned on by a power switch (not shown), power is supplied to a control circuit including the inverter 4 and the heating control means 9. When a water heating instruction is input by the operation switch 12a, the inverter 4 supplies a high frequency current to the heating coil 3 by the control operation of the heating control means 9. When a high-frequency current is supplied to the heating coil 3, a high-frequency magnetic field is generated from the heating coil 3, and the pot bottom is heated by the eddy current induced at the bottom of the pot 1 on the top plate 2. By this induction heating, the temperature of the pan 1 rises, and the heat of the pan 1 is transmitted to the water in the pan 1 to boil.

  Here, the operation of the infrared detecting means 5 will be described. When the temperature at the bottom of the pan 1 rises, infrared rays corresponding to that temperature are emitted from the pan 1. Since the ceramic material used for the top plate 2 can efficiently transmit infrared rays having a wavelength range of 2.5 μm or less, the infrared detection means 5 can detect, for example, a photodiode capable of detecting wavelengths of 2.5 μm or less. In this way, infrared rays in this wavelength range that have passed through the top plate 2 are incident on the photodiode. Further, the infrared detecting means 5 selectively collects more infrared rays and cuts off the magnetic field from the heating coil 3 due to the presence of the mirror-like reflecting cylinder 6 having a high reflectance. The amount of infrared rays radiated from the bottom is secured, and the accuracy of temperature measurement is improved.

  The temperature detecting means 7 amplifies the current generated in the photodiode corresponding to the amount of infrared light incident on the infrared detecting means 5 constituted by the photodiode after I (current) -V (voltage) conversion. And converted into temperature information and output to the boiling detection means 8. In this embodiment, the emissivity is set to 0.5 and converted into temperature information. However, the output of the temperature detection means 7 and the water temperature in the pan 1 are different from the emissivity depending on the material of the pan 1, A temperature difference occurs. When the boiling detection means 8 detects that the water in the pot 1 has boiled from the temperature change based on this temperature information, the heating control means 9 controls the inverter 4 to suppress or stop the heating output. .

  The boiling detection means 8 calculates a temperature difference at a predetermined time (for example, 10 seconds) every second, and continuously detects that it is within a predetermined temperature difference (for example, ± 1 ° C.). It is determined that the water has boiled.

  The correction means 10 stores in advance the output of the temperature detection means 7 at the point of time when boiling is detected, and corrects the output of the temperature detection means 7 based on this value and inputs it to the temperature display means 11, as shown in FIG. Show water temperature as shown. For example, if the value stored in advance is 90 (° C.), 100 (° C.) is displayed when the output of the temperature detecting means 7 becomes 90 (° C.).

  As described above, in the present embodiment, the infrared detecting means 5, the temperature detecting means 7 and the boiling detecting means 8 accurately detect boiling, and correct the difference in emissivity of the pot 1 and the difference in characteristics of the photodiode. Since the temperature is corrected by 10 and displayed, the user can know the water temperature in the pan 1 more accurately, and can provide an easy-to-use induction heating cooker.

(Embodiment 2)
FIG. 3 shows an induction heating cooker according to Embodiment 2 of the present invention. The same elements as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The present embodiment is different from the first embodiment in that the heating control means 9 has an adjustment mode for storing a value to be corrected by the correction means 10 from the temperature at the time when the boiling detection means 8 detects the boiling. That is.

  That is, an adjustment start key 12b serving as an adjustment start means for starting an adjustment mode is provided on the operation unit 12 separately from the operation switch 12a, which is a “hot water start key” that is normally used when the user starts an automatic water heating sequence. Is provided. When the adjustment start key 12b is pressed, the heating control means 9 starts the heating output operation as in the case of pressing the operation switch 12a. When the boiling detection means 8 detects the boiling of water, the heating output is suppressed or stopped. Let The difference from the case where the operation switch 12a is pressed is that the heating control means 9 stores the output of the temperature detection means 7 when the boiling detection means 8 detects the boiling of water. The value stored at this time is used when the correction means 10 performs temperature correction.

  As described above, in the present embodiment, since the heating control means 9 has the adjustment mode, the temperature adjustment displayed by the temperature display means 11 can be easily performed. Adjustment can be easily performed.

(Embodiment 3)
4 and 5 show an induction heating cooker according to Embodiment 3 of the present invention. The same elements as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In the present embodiment, the difference from the first embodiment is that, as shown in FIG. 4, the heating control means 9 includes a heating mode from the start of heating to boiling detection, and a heat retention mode for maintaining heat from boiling detection. And the heat retention temperature in the heat retention mode is set by the heat retention temperature setting means, and heating is suppressed or stopped when the temperature exceeds the temperature set by the heat retention temperature setting means.

  That is, as the heat retention temperature setting means, a down key 12c for lowering the heat retention temperature and an up key 12d for increasing the heat retention temperature are provided so that the heat retention temperature in the heat retention mode can be freely set. Then, the water temperature is compared with the temperature set by the heat retention temperature setting means.If the water temperature is higher than the set temperature, the heating is suppressed or stopped.If the water temperature is lower than the set temperature, the heating output is increased or started. The set temperature is maintained.

  FIG. 5 shows an example of the operation unit in the present embodiment, and the water temperature and the set temperature are simultaneously displayed using the LCD display element.

  As described above, in this embodiment, since the heat retention temperature after boiling can be freely set by the heat retention temperature setting means 12c and 12d, the temperature to be used can be freely set, and it is easy to use.

( Reference form 1 )
Next, the induction heating cooker in Reference Embodiment 1 of the present invention will be described with reference to FIG.

In the present reference, is a third basically the same configuration of the embodiment, after boiling detection by boiling detection means 8, retained temperature setting means 12c, the water temperature drops to retained temperature set by 12d, which This is different in that it is provided with an informing means 13 for informing. The notification by the notification means 13 may be a single or combination of voice, buzzer, light, etc., but is not limited to these as long as the notification function is satisfied.

Thus, in this reference embodiment, by providing the notification unit 13, the retained temperature to be used and can inform the user, the better is more convenient.

  As described above, the induction heating cooker according to the present invention is capable of detecting boiling with high accuracy and correcting and displaying the display temperature, so that it is easy to use. Therefore, the induction heating cooker can be widely applied not only to boiling water but also to automatic cooking. Can do.

The block diagram of the induction heating cooking appliance in Embodiment 1 of this invention Front view of display operation unit in the induction heating cooker The block diagram of the induction heating cooking appliance in Embodiment 2 of this invention The block diagram of the induction heating cooking appliance in Embodiment 3 of this invention The front view of the display operation part in Embodiment 3, reference form 1 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pan 2 Top plate 3 Heating coil 4 Inverter 5 Infrared detection means 7 Temperature detection means 8 Boiling detection means 9 Heating control means 10 Correction means 11 Temperature display means 12a Operation switch 12b Adjustment start means (Adjustment start key)
12c, 12d Thermal insulation temperature setting means (down key, up key)
13 Notification means

Claims (4)

A heating coil for heating the pan, a top plate for placing the pan on the top of the heating coil and transmitting infrared rays, an inverter for supplying a high-frequency current to the heating coil, a heating control means for controlling the inverter, Infrared detection means for detecting infrared rays that are placed below the top plate and radiated from the bottom surface of the pan and transmitted through the top plate, temperature detection means for detecting the bottom surface temperature of the pan from the output of the infrared detection means, and a user control command A water heating start key for inputting the control command for starting an automatic water heating sequence, a temperature display means for displaying the temperature detected by the output of the temperature detecting means, and the water heater. A boiling detection that determines that the water has boiled when the temperature difference of the pan bottom surface temperature detected from the output of the temperature detection means within a predetermined time difference is within a predetermined temperature difference by operating the start key. Wherein a boiling detection means for signal output to the heating control unit, and a correcting means for previously storing an output value of said temperature detecting means at the time of boiling detected by the boiling detecting means performs said correction means, said temperature Output detected by the temperature detection means on the temperature display means so that the temperature display means displays 100 ° C. when the output value detected by the detection means becomes the stored output value . An induction heating cooker that displays the temperature of the water during the automatic water heater sequence operation, the value of which is corrected by the stored output value. An adjustment start unit provided in an operation unit for inputting a user's operation command is provided, and the heating control unit is started by the adjustment start unit, and the output value of the temperature detection unit at the time when boiling is detected by the boiling detection unit The correction means corrects the output value detected by the temperature detection means based on the output value stored in the adjustment mode by the heating control means, and causes the temperature display means to display the correction value. Item 2. An induction heating cooker according to item 1. The induction heating cooker according to claim 1 or 2, wherein the infrared detection means includes a photodiode capable of detecting a wavelength of 2.5 µm or less, and the top plate is made of ceramic. The heating control means has a heating mode from the start of heating until boiling is detected, and a warming mode in which heat is kept at a warming temperature set lower than the boiling temperature from the boiling detection, and the warming temperature in the warming mode is the warming temperature. The induction heating cooker according to any one of claims 1 to 3, wherein the induction heating cooker is set by temperature setting means.

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