JPH03190083A - Cooking device - Google Patents

Abstract

PURPOSE:To prevent cooking failure due to heating interruption by detecting a rise of intake-air temperature up to an undesired high temperature. CONSTITUTION:When a switching element 9 turns on and off through an inverter control circuit 15 and a high frequency alternating field is generated from a coil 9 so that the cooking device, is induction-heated and, for example, an intake-air temperature is increased due to a discharge air heat in the surroundings, and an intake-air signal voltage VTM related to a temperature detected by a thermistor 5 reaches a first reference temperature signal voltage V1, an output of a first comparator 19 from a high level to a low level, and a signal thereof is inputted into a display circuit 16 so that a light emitting diode 6 emits light. It is thereby possible to find that the intake-air temperature has reached a high temperature, to remove a cause of the temperature rise, and to prevent cooking failure without undesired stopping of the cooking halfway.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a cooking device such as an induction cooking device.

(b) The conventional induction heating cooker disclosed in Japanese Utility Model Application Publication No. 63-179690 is provided with a temperature detection means for detecting the temperature of a radiation fin of a switching element for driving a heating coil. The induction heating is configured to stop when the detected temperature reaches a predetermined reference temperature.

However, in such a cooking device, no measures are taken in case the intake air temperature of the induction heating cooking device body rises to an undesirably high temperature. An increase in the intake air temperature to an undesirably high temperature is caused by
This can occur when the induction heating cooker is affected by equipment surrounding it, when the intake air path is blocked, or when the intake filter becomes dusty and air cannot be taken in.

On the other hand, even if measures are taken to prevent such an undesirable increase in intake air temperature, it is impossible to know that the intake air temperature is reaching an undesired high temperature, so The configuration is such that induction heating is stopped immediately when a high temperature is reached, and induction heating is interrupted and cooking fails.

(c) Problems to be Solved by the Invention The present invention has a structure that can detect an increase in intake air temperature to an undesired high temperature, and detects such a rise in temperature in advance and eliminates the cause thereof in advance. It is an object of the present invention to provide a cooking device that can prevent heating from being interrupted and cooking failures.

(d) Means for Solving the Problems The cooking appliance of the present invention includes a temperature detection means for detecting an intake air temperature, and a first comparison for comparing the intake air temperature detected by the temperature detection means with a first reference temperature. means, a notification means that operates when the first comparison means compares and determines that the intake air temperature has reached the first reference temperature, and a second comparison means that compares the intake air temperature and the second reference temperature. and a stop means for stopping the heating operation when the second comparison means compares and determines that the intake air temperature has reached the second reference temperature.

(E) Since there is a temperature detection means for detecting the working intake air temperature, an undesirable increase in the intake air temperature can be detected.

In this case, the intake air temperature detected by this temperature detection means is the first
When the reference temperature is reached, the notification means is activated to notify that the intake air temperature is reaching an undesirably high temperature, and the cause of this can be removed before the cooking stops.

If the cause is not removed despite such notification, the intake air temperature reaches the second reference temperature, which is an undesirably high temperature, and the heating operation is stopped.

(f) Embodiment FIGS. 1 and 2 show the structure of a built-in induction heating cooker according to an embodiment of the present invention, and the cooker is divided into a main body part 1 and a control part 2. A plurality of intake holes 3 are formed on one side of the main body 1, and a thermistor 5, which is a temperature detector, is attached to the intake hole via a metal fitting 4 to detect the intake air temperature. . Further, the control section 2 is provided with a light emitting diode 6 and the like as a notification means.

FIG. 3 shows the overall circuit of the induction heating cooker, which includes an induction heating coil 7, a resonant capacitor 8 that forms a resonant circuit together with the coil, a switching element 9 that connects the coil 7 and generates an excitation current, A high frequency inverter 11 consisting of a damper diode 10 connected in antiparallel to the switching element is connected to a commercial AC power supply in a full wave rectifier circuit 1.
Connected to 2.

On the other hand, an intake air temperature control circuit 13 is provided, and the intake air temperature control circuit inputs the divided voltage VTM generated by the thermistor 5 and the first resistor 14 as a signal of the intake air temperature detected by the thermistor 5, It performs signal output control for the control circuit 15 and display circuit 16. The inverter control circuit 15 controls the switching element 9 on and off via the drive circuit 17 based on the signal from the intake air temperature control circuit 13, etc., and thereby a high frequency current is supplied to the coil 7. A high frequency alternating magnetic field is generated from the coil 7, and induction heating is performed. In addition, the display circuit 1
6 controls the light emission of the light emitting diode 6 based on the signal from the intake air temperature control circuit 13.

FIG. 4 shows details of the intake air temperature control circuit 13, in which the intake air temperature signal voltage vTM obtained by the voltage division between the thermistor 5 and the first resistor 14 as described above is smoothed by the capacitor 18,
Input to one input terminal of comparison 9 #19. A first reference temperature signal voltage V, (corresponding to 4oC) divided by the second and third resistors 20.21 is connected to the input terminal of the first comparator.
enters.

Furthermore, the intake air temperature signal voltage V7M is also input to one input terminal of the second comparator 22. A second reference temperature signal voltage V (corresponding to 4 s° C.) divided by the third and fourth resistors 23 and 24 is input to the input terminal of the second comparator. A feedback resistor 25.26 is connected to each of the first and second comparators 19.22. The output of the first comparator 19 is input to the display circuit 16 via the first diode 27, and the output of the second comparator 22 is input to the inverter control circuit 15 via the second diode 28.
Enter.

To explain the operation of the intake air temperature control circuit 13, the switching element 9 is turned on and off based on the control of the inverter control circuit 15, and a high-frequency alternating magnetic field is generated from the coil 7 to perform induction heating. When the
For example, the intake air temperature becomes high due to the influence of equipment that emits hot exhaust air around the induction heating cooker, and the intake air temperature signal voltage v5 related to the intake air temperature detected by the thermistor 5 becomes the first reference temperature signal voltage. When V is reached, the first
The output of the comparator 19 changes from high level to low level, and this low level signal is input to the display circuit 1G. Then, the display circuit 16 controls the light emitting diode 6 to emit light, and the light emitting diode 6 emits light to notify that the intake air temperature is reaching a high temperature. This allows the user to immediately remove the cause of the intake air temperature rising to a high temperature. In this case, surrounding devices that emit hot exhaust air can be moved away from the induction heating cooker. Alternatively, the induction heating can be interrupted at a convenient point and the cause can be removed as described above. In this way, if the cause of the intake air temperature is removed before it reaches a high temperature, induction heating cooking can be performed without undesirably stopping midway through, and cooking failures will not occur.

On the other hand, if the cause of the intake air temperature reaching a high temperature is not removed despite the above notification, the intake air temperature signal voltage VTM will eventually rise to the second reference temperature signal voltage Vt.
, the output of the second comparator 22 changes from a high level signal to a low level signal, and this low level signal is input to the inverter control circuit 13, which causes the inverter control circuit 15 to turn on the switching element 9. - Stops off control and interrupts induction cooking. When cooking is interrupted in this way, the temperature of the intake air no longer increases, and the electronic components inside the cooker that are cooled by the intake air are protected.

Here, the inverter control circuit 15 corresponds to the stopping means of the present invention.

As described above, when the outputs of the first and second comparators 19.22 change to a low level, each feedback resistor 25.26 acts, and the input terminals of each comparator 19.22 both receive the third reference. Temperature signal voltage V.

(corresponding to 38°C) is input. In this situation, if the intake air temperature drops due to the interruption of cooking,
Eventually, the intake air temperature signal voltage VTM becomes equal to or less than the third reference temperature signal voltage V, and the outputs of the comparators 19 and 22 return to the high level again. Then, the light emission control of the light emitting diode 6 is released, and the switching Turning on element 9,
The stop of the off control is also released.

In the above embodiment, the intake air temperature signal voltage VI is
When the reference temperature signal voltage V is reached, the light emitting diode 6
In addition to controlling the light emission, the output of induction heating may be reduced.

(g) Effects of the Invention According to the present invention, by having a configuration that can detect an increase in intake air temperature to an undesired high temperature, it is possible to know in advance of such a rise in temperature and eliminate the cause thereof. This makes it possible to prevent cooking failure due to undesired heating interruption, and to provide a practical cooking device.

[Brief explanation of drawings]

The drawings relate to an induction heating cooker according to an embodiment of the present invention, and FIG. 1 is an external perspective view, FIG. 2 is a perspective view of a main part, FIG. 3 is an overall circuit diagram, and FIG. 4 is a main part circuit diagram. 5... Thermistor (temperature detection means), 6... Light emitting diode (notification means), 15... Inverter control circuit (stopping means), 19... First comparator, 22... Second
Comparator.

Claims (1)

[Claims] (1) A temperature detection means for detecting the intake air temperature; a first comparison means for comparing the intake air temperature detected by the temperature detection means with a first reference temperature; a notification means that operates when it is determined by comparison that the first reference temperature has been reached; a second comparison means that compares the intake air temperature with a second reference temperature; A cooking device comprising a stop means for stopping a heating operation when it is determined by comparison that a second reference temperature has been reached.