JPH0919364A - Induction heating rice cooker - Google Patents

Abstract

(57) [Summary] [Purpose] To control the water temperature to the optimum temperature and realize a rice cooking process close to the ideal rice cooking conditions. [Configuration] An output of an inverter 1 is appropriately switched and supplied by a control means 10 to a magnetron 5 which receives outputs of a heating coil 3 and a high frequency transformer 4 and outputs a microwave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker which uses a heating coil and a microwave for heating and cooking.

[0002]

2. Description of the Related Art Conventionally, this type of rice cooker heats a pot by an induction heating method, detects the capacity of an object to be heated by the output of temperature detecting means arranged on the pot or the upper lid, and outputs the detected result. Accordingly, the rice cooking process such as the determination of the heating time was controlled. That is, the rice is cooked in a pre-cooking process at a relatively low temperature for a certain period of time to allow the rice to absorb water sufficiently, and in the boiling process called boiled heating to change the rice from β starch to α starch, and then cook the rice. There are three steps, namely, the step of changing to (1), and the step of vaporizing unnecessary water, which is called additional cooking, to further promote α-starch formation. These steps are output by the temperature detection means attached to the bottom of the pan etc. It was general to control by the induction heating method by utilizing.

Further, after the rice is cooked, the temperature in the pan is kept constant by a heat insulation heater to prevent the rice from deteriorating and to maintain the rice in a state close to freshly cooked.

[0004]

However, the above conventional rice cookers have the following problems. That is, although the convection of the object to be heated in the pan is sufficiently performed by the induction heating method, the temperature during the pre-cooking process may be uniform depending on the amount of the object to be heated or the amount of water in which the object to be heated is immersed. In some cases, it is difficult, and in some cases, unnecessary water vapor cannot be sufficiently vaporized during additional cooking, making it difficult to finely control the heating means.

Further, in the conventional rice cooker, since the amount of cooked rice is judged by the curve of the temperature rise during cooking, it is not possible to judge the amount of cooked rice when it is kept warm, and it is appropriate for the amount of cooked rice. It was difficult to control.

Therefore, according to the present invention, the temperature is made uniform during the pre-cooking process or unnecessary moisture is vaporized during the additional cooking regardless of the amount of the object to be heated or the amount of water in which the object to be heated is immersed. It is a first object to provide a rice cooker capable of improving the taste by fully performing the above.

A second object is to finely control the rice cooking by a plurality of heating sources to bring the rice cooking process closer to the ideal.

The third purpose is to control rice cooking more finely than the second purpose, thereby controlling the temperature during rice cooking.
It is to bring the moisture absorption process closer to the ideal.

A fourth object is to prevent the operation from being unstable when switching the output of the inverter and the generation of unnecessary noise.

A fifth object is to improve the heat retention performance by selectively using any one of heating by a heating coil, heating by a microwave and heating by a heat retaining heater.

[0011]

In order to achieve the above first object, the present invention provides an inverter, a heating coil and a high frequency transformer driven by the inverter, and a microwave receiving the output of the high frequency transformer. And a cavity for receiving the microwave guided to the waveguide, and a control means for controlling the output of the inverter, wherein the control means outputs the output of the inverter to the heating coil or the high frequency transformer. It controls the switching means for switching to.

In order to achieve the second object, the present invention particularly comprises a capacity detecting means for measuring the capacity of the object to be heated in the cavity and a temperature detecting means for detecting the temperature in the cavity. The control means controls the switching means according to the output of at least one of the capacity detecting means and the temperature detecting means.

Further, in order to achieve the third object, the control means of the present invention controls the output of the inverter intermittently in accordance with at least one output of the capacity detecting means and the temperature detecting means. Is.

In order to achieve the fourth object, the control means of the present invention is such that the switching operation by the switching means is performed especially when the inverter is not driven.

Further, in order to achieve the fifth object, the control means of the present invention has at least one of a heating coil, a high frequency transformer and a heat retention heater, depending on at least one output of the capacity detecting means and the temperature detecting means. One is controlled by intermittent drive.

[0016]

The present invention makes it possible to properly control the water temperature of the lower layer and the water temperature of the upper layer of the heated object by using both the induction heating and the microwave heating having the above-mentioned configuration, and at a relatively low temperature where convection does not easily occur. Even if there is, the water temperature can be made uniform and a rice cooking process close to ideal rice cooking conditions can be realized.

Further, by providing the capacity detecting means and the temperature detecting means, the heating method can be selected in each step according to the detection output, and the water temperature can be made uniform even if the convection is relatively low and the convection is hard to occur. And can realize a rice cooking process close to ideal rice cooking conditions.

Further, the control means intermittently drives the inverter according to the outputs of the capacity detecting means and the temperature detecting means to enable more accurate temperature control, and the heating method in each step. By selecting and further controlling the operating time of each heating method, the rice cooking process close to the ideal rice cooking conditions can be realized.

Further, by temporarily suspending the operation of the inverter when performing the switching operation of the inverter output, it is possible to prevent the operation instability, noise, and wear of the relay contact which occur at the time of switching.

Further, according to the output of the capacity detecting means, microwave heating is performed from the upper side, heating is performed by a heating coil from the lower side, and warming heater heating is performed from the side, so that the warming temperature is managed more finely, The heat retention performance during the heat retention operation can be significantly improved.

[0021]

【Example】

(First Embodiment) An embodiment of the high frequency rice cooker of the present invention will be described below with reference to FIG.

Reference numeral 1 is an inverter for rectifying electric power of an AC commercial frequency to perform high frequency switching, and 2 is a switching means for switching the output of the inverter 1 to the heating coil 3 and the high frequency transformer 4 and supplying the same. Reference numeral 5 denotes a magnetron, which is supplied with the high voltage and the heater voltage which are boosted and rectified by the high frequency transformer 4 to output microwaves. Reference numeral 6 is a waveguide for guiding the microwaves emitted from the magnetron 5 to the cooking object contained in the cavity 8 and the pan 7. 10 is a control means,
According to the outputs of the capacity detecting means 9 and the temperature detecting means 12, the inverter 1, the switching means 2 and the heat retaining heater 11 are provided.
To control a series of.

Reference numeral 9 is a capacity detecting means for determining the capacity of the object to be heated in the pan, and may be, for example, a radio wave, a sound wave or an optical means. Here, as an example thereof, a case of determining the capacity by radio waves will be described.
Microwave output is obtained by driving the magnetron 5, and the microwave emitted from the antenna of the magnetron 5 is applied to the object to be heated via the waveguide 6 and the cavity 8. Here, the object to be heated is heated. Since the microwaves absorbed by the object and the microwaves partially reflected are mixed, the capacity of the object to be heated is determined by the amount of the reflected microwaves.

The operation of the above arrangement will be described below. When the rice cooking start switch (not shown) is pressed to start the rice cooking, the control means 10 connects the inverter 1 to the heating coil 3 by the switching means 2 and then confirms that the pan 7 is set correctly by monitoring the energizing current. To detect. Here, if the pot 7 is properly set, the heating coil 3 is continuously energized, and while monitoring the output of the temperature detection means 12, the procedure programmed in the control means in advance, for example, the first one minute is heated. The heating of the lower part of the object to be heated by the heating by the coil 3 promotes the water temperature increase of the lower part of the object to be heated, and the next 2 minutes, the heating of the upper part of the microwave promotes the increase of the water temperature of the object to be heated. In order to prevent the rice from sticking due to excessive moisture in the additional cooking process, the switching means 2 is driven in order such as to make the temperature rise uniform, and the high-frequency transformer 4 and the heating coil 3 are sequentially switched. By heating, the taste of the finished rice is improved.

(Second Embodiment) A second embodiment of the present invention will be described.

In accordance with the output of the capacity detecting means 9 or the temperature detecting means 12, the output of the inverter 1 is switched to the heating coil 3 and the high frequency transformer 4 by the switching means 2 as in the first embodiment, and the heating pattern is optimized. It is controlled so that As the amount of cooked rice changes, the time required for heating by the heating coil 3 and the time required for microwave heating naturally change. Therefore, it is possible to manage the operating time according to the capacity measurement result from the capacity detecting means. In the cooking process, the water temperature is made uniform, and in the after-cooking process, the stickiness of the rice due to excessive moisture is prevented to improve the taste of the finished rice.

(Third Embodiment) A third embodiment of the present invention will be described.

According to the output of the capacity detecting means 9 or the temperature detecting means 12, the output of the inverter 1 is switched to the heating coil 3 and the high frequency transformer 4 by the switching means 2, and the output of the inverter 1 is intermittently changed. By controlling, not only the heating of the upper part or the lower part of the cavity can be switched, but also the output of the heating coil 3 and the microwave can be finely controlled according to the output of the capacitance detecting means. In the pre-cooking process, the water temperature is made uniform, and in the after-cooking process, the stickiness of the rice due to excessive moisture is prevented to further improve the taste of the finished rice.

(Fourth Embodiment) A third embodiment of the present invention will be described.

The output of the inverter 1 is switched to the heating coil 3 and the high frequency transformer 4 by the switching means 2 and supplied.
At this time, by stopping and switching the operation of the inverter 1, there is no switching when a large current is flowing from the inverter 1. Therefore, sparks generated at that time can be prevented and the circuit operation can be stabilized.

(Fifth Embodiment) Reference numeral 11 denotes a heat-retaining heater, which is energized to keep the temperature of the rice constant during heat-retention, but the capacity detecting means 9 is operated at predetermined intervals during the heat-retaining process to heat the rice. Knowing the capacity of the object, and further operating the inverter 1 based on the temperature information of the temperature detecting means 12, driving the heating coil 3, driving the magnetron, and intermittently energizing the heat retaining heater to control the temperature of the heat retaining. Is to do. In the conventional warming operation, the warming temperature was managed by the temperature sensor provided at the bottom or side of the pan 7, but for the purpose of improving the warming performance, keep the temperature during warming low and reheat just before eating. By doing so, it is possible to prevent the deterioration of rice during heat retention, and to try to heat it to a temperature close to freshly cooked when eating. In this way, in order to optimally control the heat retention temperature from the top of the cavity 8, It is necessary to appropriately switch the heating, the heating from the lower side, and the heating from the side surface depending on the capacity to perform the heat retention operation.
The heating by the warming heater 11 is optimally used properly, and the warming operation close to the ideal is possible.

[0032]

As described above, according to the present invention, the rice cooked by the heating coil and the rice cooked by the microwave are appropriately switched,
It effectively keeps the water temperature at the target temperature and realizes a rice cooking process close to ideal rice cooking conditions.

Further, by supplying the output of the inverter to the high frequency transformer or the heating coil in accordance with the output of at least one of the capacity determining means and the temperature detecting means, the water temperature can be kept more appropriately at the target temperature and ideal rice cooking can be achieved. It realizes a rice cooking process close to the conditions.

By intermittently controlling the operation of the inverter, it becomes possible to finely control the water temperature according to the target temperature.

When switching the output of the inverter,
By temporarily stopping the operation of the inverter and performing the switching operation, it is possible to prevent switching noise and operation instability that occur when switching the relay.

Further, heating with a heating coil, heating with a microwave, and heating with a heat-retaining heater are used in combination, and the capacity of the cooked rice is judged and controlled by the capacity judging means or the like at the time of warming as well. The optimum heating means is selectively used to further improve the heat retention performance and enable long-term heat retention.

[Brief description of the drawings]

FIG. 1 is a main configuration diagram of a high-frequency heating rice cooker showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter 2 Switching means 3 Heating coil 4 High frequency transformer 5 Magnetron 6 Waveguide 7 Pan 8 Cavity 9 Capacitance detecting means 10 Control means 11 Insulation heater 12 Temperature detecting means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Oshio 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Seiichi Taniguchi 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Machiko Miyai 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Shinichiro Sumiyoshi Osaka Kadoma City, Kadoma City 1006 Matsushita Electric Industrial Co., Ltd. (72) Inventor Satoshi Nakae Osaka Prefecture 1006 Kadoma, Kadoma-shi, Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An inverter, a heating coil and a high frequency transformer driven by the inverter, a magnetron which receives the output of the high frequency transformer and outputs a microwave, and a cavity which receives the microwave guided to a waveguide. And a control means for controlling the output of the inverter, the control means controlling switching means for switching the output of the inverter to the heating coil or the high frequency transformer. 2. A capacity detecting means for measuring the capacity of the object to be heated in the cavity, and a temperature detecting means for detecting the temperature in the cavity, wherein the control means is the capacity detecting means,
The high frequency heating rice cooker according to claim 1, wherein the switching means is controlled according to at least one output of the temperature detecting means. 3. The high frequency heating rice cooker according to claim 1, wherein the control means controls the output of the inverter intermittently in accordance with the output of at least one of the capacity detecting means and the temperature detecting means. 4. The control means performs the switching operation by the switching means when the inverter is not driven.
~ The high frequency heating rice cooker according to claim 3. 5. The control means intermittently drives and controls at least one of a heating coil, a high frequency transformer and a heat retention heater in accordance with the output of at least one of the capacity detection means and the temperature detection means. The high frequency heating rice cooker according to any one of 4 above.