JPH01185222A - Rice boiler - Google Patents

Abstract

PURPOSE:To prevent temperature unevenness and burning of rice due to reheating by forming a reheating heater circuit, having a thermal value larger than the heater thermal value in a warm keeping process, mainly of warm keeping heaters and driving the reheating heater circuit reheating the rice. CONSTITUTION:A vessel 11 containing boiled objects 17, 18, warm keeping heaters 8, 9 provided corresponding to a rice boiling heater 7 heating this vessel 11 and to its barrel part, heater driving means 27, temperature detecting means 20 detecting a temperature of the vessel 11 and a control means 21 executing in series each process of rice boiling and warm keeping or the like are provided. The control means 21 forms a reheating heater circuit, having a thermal value larger than the heater thermal value in a warm keeping process, mainly of the warm keeping heaters 8, 9, and reheating can be performed by driving the reheating heater circuit. In this way, in the time of reheating, the vessel 11 is totally reheated mainly by the warm keeping heaters 8, 9 provided corresponding to the barrel part of the vessel 11.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a rice cooker that is capable of reheating rice that has been kept warm.

(Prior Art) This type of conventional rice cooker heats a pot, which is a container containing rice and water to be cooked, using a rice cooker provided at the bottom of the pot, and then cooks the rice. The steel is heated and kept warm by a heat-retaining heater provided corresponding to the steel body. When the moisturized rice is reheated, the warming process is once completed, and then the rice cooking process is performed by heating the pot with the rice cooking heater.

(Problems to be Solved by the Invention) In the above conventional technology, when reheating rice that has been kept warm, the rice cooker heats the steel and repeats the rice cooking process. There is a problem in that the rice is reheated from the bottom, and the heat is not easily transmitted to the top of the rice in the pot, resulting in uneven reheated rice, and the rice at the bottom of the pot is likely to burn.

Therefore, an object of the present invention is to provide a rice cooker that can prevent as much as possible the temperature unevenness and charring of rice due to reheating.

[Structure of the Invention] (Means for Solving Problems) The present invention provides a container 11 for storing rice to be cooked 17, 18, a rice cooking heater 7 for heating this container 11, and the container 11.
Insulating heaters 8 and 9 provided corresponding to the body of the container, a heater driving means 27, a temperature detecting means 20 for detecting the humidity of the container 11, and a control system that sequentially executes each process such as rice cooking and keeping warm. The control means 21 includes a reheating heater circuit 32G mainly composed of the heat retention heaters 8 and 9, which has a calorific value larger than the heater calorific value in the heat retention process, and this reheating heater circuit 32G It can be reheated by driving the 32C.

(Function) With the above configuration, when reheating the container 11, the heat retaining heater 8°9 provided corresponding to the body of the container 11 is used mainly to heat the container 1.
1 is completely reheated.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

3 and 4 show the schematic structure of a rice cooker. In the figures, 1 is a main body, and this main body 1 includes a substantially bottomed cylindrical outer frame 2, and a substantially cylindrical outer frame 2 disposed within this outer frame 2. An inner frame 3 having a cylindrical shape with a bottom, a frame body 4 connecting the upper ends of the inner frame 3 and the outer frame 2, and a reflecting plate 6 provided at the bottom of the inner frame 3 via a spring 5; A rice cooking heater 7 of, for example, 600 W provided on the upper surface side of the reflector 6, and two heat-retaining heaters 8 of, for example, 100 W mounted on the outer peripheral surface of the inner frame 3.
, 9 are embedded therein. Reference numeral 11 denotes a pot which is a substantially bottomed cylindrical container housed in the inner frame 3, and one side is located below the center line Q of the height of the pot 11 when the pot 11 is accommodated in the inner frame 3. Thermal heater 8
is provided, and the other heat-retaining heater 9 is provided above.

12 is a spring 5A attached to the center opening 6A of the reflecting plate 6.
It is a temperature sensor such as a thermistor disposed inside the receiving tube 13 provided through the spring 5A, and the receiving tube 13 is brought into contact with the bottom of the steel 11 by the bias of the spring 5A. 14 is a lid body, and an inner lid 15 is integrally provided on the lower surface of this lid body 14. Reference numeral 16 is provided integrally on the upper part of the inner frame 3, and the inner circumferential surface is coated with a surface treatment such as a metal oxide coating or black coating at the locations corresponding to the heat-retaining heaters 8 and 9. As shown in the explanatory diagram of FIG.
A rice cooking heater 7 and heat-retaining heaters 8 and 9 are provided in a state where they are shifted by 180 degrees from each other. Further, rice 17 and water 18, which are to be cooked, are housed in the steel 11.

FIG. 2 is a block diagram showing the electrical configuration. In the same figure, 19 is an A/D converter which together with the temperature sensor 12 constitutes a temperature detection means 20, and the temperature of the pot 11 is detected by the temperature detection means 20. is detected, and a temperature detection signal corresponding to this detected temperature is output. 21 is a control means consisting of a microcomputer, which, as is well known, controls the A/D
Converter 19. CPU22. Timer circuit 23, memory 2
4. Input time 25. It includes an output circuit 26 and the like. This control means 21 controls the drive of the rice cooking heater 7 and the heat retention heaters 8 and 9 according to the control program it owns, and further detects the capacity and controls the rice cooking process based on the detected temperature from the temperature detection means 20. Detects the dry-up state in the reheating process, and also detects the reheating completion state in the reheating process. A relay drive circuit 27 is a heater drive means, which is connected to the output circuit 26, and turns on each relay switch described later by a signal from the control means 21.

It is turned off to perform switching control of the heater circuit, which will be described later. 36 is an IC reheating instruction means connected to the input circuit 25.

FIG. 1 shows a circuit diagram, and as shown in the figure, the rice cooking heater 7 is connected to the output terminal of the power supply voltage e via the contact 28B of the first relay switch 28, and the second and third relay switches are connected to the output terminal of the power supply voltage e. 29° and 30 are connected in series. Further, the contact 28C of the first relay switch 28 and the contact 29A of the second relay switch 29 are connected, and the fixed contact 28△ of the first relay switch 28 is connected.
and second. One of the heat-retaining heaters 8 is connected between a common fixed contact 31 of the third relay switches 29 and 30. Also, the fixed contact 28A of the first relay switch 28
The other heat-retaining heater 9 is connected between the contact point 30A of the third relay switch 30 and the heater circuit 32. On the other hand, the control means 21 is connected to the output terminal of the power supply voltage e via the power transformer 33 and the DC power supply circuit 34, and the temperature sensor 12 is connected to the input side of the control means 21, and the output terminal The relay drive circuit 27 is connected to the side.

Next, the operation will be explained with reference to FIGS. 5 to 9.

First, when a rice cooking start switch (not shown) is turned on, a rice cooking signal is output from the control means 21, and this rice cooking signal causes the relay drive circuit 27 to switch the first relay switch 28 to contact 28B as shown in FIG. Connect with the second
and the third relay switch 29.30 as the contact 29A,
3OA to form a rice cooking heater circuit 32A.

In this rice cooking heater circuit 32A, the rice cooking heater 7 and the heat retention heaters 8 and 9 are mutually connected in parallel, and the rice cooking heater 7 generates a high amount of heat. In other words, rice cooking heater 7 600
W and the 200 W of the heat-retaining heaters 8 and 9 provide an output of 800 W. Then, by appropriately turning on and off the power at this high output, the soaking process is executed, and then the rice cooking process is started. In this rice cooking process, the pot 11 is heated at a high output, and after the temperature detected by the temperature detection means 20 reaches the boiling temperature, the inside of the pot 11 is in a dry-up state based on the detected temperature. When the rice cooking heater circuit 32A is detected, the heating by the rice cooking heater circuit 32A is stopped to complete the rice cooking process, and then the rice cooking heater circuit 32A is turned off at the high output and the uneven process is performed for a predetermined period of time, for example, about 15 minutes. After that, move on to the warming process. In this heat retention process, a heat retention signal is output from the control means 21, and this signal causes the relay drive circuit 27 to turn off the first and third relay switches 28 and 30 as shown in FIG. 8, and turn on the heat retention heater circuit 32B. Form. This heat retention heater circuit 32B
The rice cooking heater 7 and the heat-retaining heaters 8 and 9 are connected in series, and the amount of heat generated by the heat-retaining heaters 8 and 9 is low. In other words, approximately 46W output is obtained with 3.6W of the rice cooking heater 7 and 42W of the warming heater. Then, by appropriately turning on and off electricity at this low output, a predetermined heat retention temperature, for example, 73° C. is maintained.

During this warming process, when the reheating instruction means 36 is turned on, a reheating signal is output from the control means 21, and this signal causes the relay drive circuit 27 to switch the first relay switch 28 to contact 28G as shown in FIG. the second relay switch 29 is turned off, and the third relay switch 30 is connected to the contact point 30A to turn off the reheating heater circuit 3.
Forms 2C. In this reheating heater circuit 32C, the heat retention heaters 8 and 9 connected in parallel to each other are connected in series to the rice cooking heater 7, and the amount of heat is intermediated mainly by the heat retention heaters 8 and 9. Zunawachi rice cooking heater 7 37W and heat retention heaters 8 and 9
Approximately 150W output of 112.5W is obtained. Then, the pot 11 is reheated with a medium output by this reheating heater circuit 32C, and in the process, as shown in FIG. Set the time T1 from point pa at 87°C to point pb at 87°C to Calan 1, calculate the temperature increase rate from the rising temperature t1 and time T+ between the two points pa and pb, and make sure that this temperature rise rate is below a predetermined range. If so, the volume 1 of the reheated rice is detected as a large volume, if it is within a predetermined range, it is detected as a medium volume, and if it is above a predetermined range, it is detected as a small volume. The temperature increase rate in the reheating completion state, which will be described later, is set as 4° C./9 minutes for large capacity, 4° C./6 minutes for medium capacity, and 4° C./3 minutes for small capacity. In this way, the temperature t2-4 continues to rise from a predetermined temperature, for example, 80°C, before the detected temperature reaches 100°C.
The elapsed time T2 with respect to °C is calculated, and when the temperature rise rate calculated from the rising temperature t2 and time T2 reaches the above set value set according to the reheating capacity, the rice in the pot 11 is displayed on the PC as shown in Fig. 6. It is detected that the reheating has actually reached 100°C as shown in the curve, and the process moves to the above-mentioned heat retention process.

In this way, in the above embodiment, during reheating, the heat retention heaters 8 and 9 connected in parallel to each other are connected in series to the rice cooking heater 7 in response to a reheat signal from the control means 21, so that the heat retention heaters 8 and 9 are used as the main heaters. Since it is configured to be reheated at a medium output, the moeki pot 11 (inner frame 3 corresponding to the other body)
112.5 W by the heat insulating heaters 8 and 9 installed in
The rice is indirectly heated at 37W by the rice cooker heater 7 provided at the bottom of the pot 11, and then reheated by the rice cooker heater 7 and the heat-retaining heaters 8 and 9 so as to wrap around the pot 11. In this way, since the body side of the pot 11 is reheated mainly and the body of the pot 11 is reheated, uneven temperature and scorching of the rice in the pot 11 can be prevented as much as possible. In the conventional method, the rice is continuously reheated to the finished temperature of, for example, about 120°C in the rice cooking process, which tends to cause a lot of charring, but in this example, first, the rice is heated at two predetermined points between pa and pb before the detected temperature reaches 100°C. Large, medium, and small reheating capacities are detected based on the temperature increase rate tt/T+, and the end point of the reheating process is determined based on the temperature increase rate t2/T2 set according to the detected capacity. Since PC is detected, unnecessarily heating can be prevented and rice with good taste can be obtained.

In addition, during rice cooking, the rice cooking heater 7 and the moisturizing heaters 8 and 9 are connected in parallel according to the rice cooking signal from the control means 21, and the rice is cooked with a high output mainly from the rice cooking heater 7. 11 is 600 by rice cooking heater 7
heated by
The rice is heated with W, and in this way, the rice is well cooked so as to wrap around the pot 11. For this reason, heating unevenness during rice cooking is reduced, and rice 17 absorbs more water 18 in areas where the water temperature rises quickly, but rice 18 absorbs less water 18 in areas where water temperature rises slowly, resulting in less water 18 being absorbed in the pot. It is possible to prevent the phenomenon that the rice at the periphery and the top of the container becomes soft and the center and bottom become hard.

In addition, during heat retention, the rice cooking heater 7 and the heat retention heaters 8 and 9 are connected in series in response to a heat retention signal from the control means 21, and the IC is configured such that the heat retention heaters 8 and 9 are kept warm with a small output mainly. The steel 11 is heated at 42W by the heat-retaining heaters 8 and 9, and the rice cooker 7 is heated to 3.
It is heated with 6W, and in this way, it is possible to keep the w411 warm as a whole, and it is also possible to suppress temperature changes in the pot 11 when the power is turned on and off.

In addition, since the rice cooking heater 7 generates heat in the closed space formed by the bottom of the pot 11 and the reflector 6, the heat is transmitted to the center of the bottom of the pot 11, which is relatively distant from the rice cooking heater 7, and the steel 11 is heated.
The bottom of the tube is heated approximately evenly. In this case, in the case where the heating plate (not shown) of the rice cooking heater 7 is brought into contact with the periphery of the bottom of the steel 11, there is a large temperature difference between the contacted part and the non-contacted part, which tends to cause uneven heating. In the embodiment, uniform heating is possible by the reflection plate 6.

Furthermore, as shown in FIG. 4, the mouth portion 7A of the rice cooking heater 7 and the mouth portions 8A, 9A of the heat-retaining heaters 8, 9 are configured to be shifted by 180 degrees from each other, so that the amount of heat generated by each heater 7, 8, 9 is reduced. The weak points of mouth parts 7A, 8A, and 9A, which are decreasing, can be mutually compensated for, and it is possible to prevent partial heat loss as much as possible. It can eliminate the phenomenon of denting. Also, moisturizing heaters 8, 9
Since one of these is provided above the center of the height of the steel 11 and the other is provided below the center of the height of the steel 11, the heating state from the body of the WAll can be approximately uniform, and the heating of the upper inner frame 16 can be made approximately uniform. The heat from the heat retaining heaters 8 and 9 is transferred to the pot 1 by surface treatment such as metal oxide coating or black coating formed on the inner peripheral surface.
The entire body of No. 1 can be heated approximately evenly.

10 to 12 show another embodiment of the present invention, and the same reference numerals are used for the same parts as in the above embodiment, and explanations of the same parts are omitted. In this embodiment, in the heater circuit 32, Fixed contact 2 of first relay switch 28
Fourth relay switch 35 with 8A as a common fixed contact
is provided, and this relay switch 35 turns on the heat-retaining heater 8.
, 9 can be moved toward and away from each other. In the rice cooking process, the control means 21 determines the time T3 for reaching the temperature rise t3 between two predetermined points, for example, the time Pd when the detected temperature is 70°C and the time pe when the detected temperature is 80°C. large and medium as well as the capacitance detection described above based on the temperature rise rate ts/Ts.

A small capacity is detected, and when a large capacity is detected, a large capacity signal is output from the control means 21. As shown in FIG.
Forming a large capacity heater circuit 32 [) with a large output of W,
In the case of medium capacity, the fourth relay switch 35 is turned off by the medium capacity signal output from the control means 21, and as shown in FIG. In the case of a small capacity, the first relay switch 28 is further turned off by the small capacity signal output from the control means 21, and as shown in FIG. A small capacity heater circuit 32F is formed, and in this way, the amount of heat generated according to the rice cooking capacity is determined by large, medium and small capacity heater circuits 32D, 32E, mainly formed of the rice cooking heater 7.
32F, which allows the rice cooking heater 7 and the heat retention heaters 8 and 9 to heat the pot 11 as a whole to cook rice, and also to cook rice according to the rice cooking capacity.
.

By cooking rice with an appropriate amount of heat, energy loss can be prevented.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, the number of heat-retaining heaters and the connection state of the heater circuit can be selected as appropriate.Also, the end of reheating was detected when the temperature of the rice reached 100°C, but it can be detected at an appropriate temperature of 90°C or higher. You can do it like this. Moreover, the general structure of the rice cooker can be applied to various types. Furthermore, although each function of the control means is provided by a microcomputer, it may also be provided by an individual electronic circuit.

[Effects of the Invention] The present invention forms a reheating heater circuit which has a heat generation amount larger than the heat generation amount of the heater during the heat retention process, mainly using a heat retention heater, and performs reheating by driving this reheating heater circuit. It is possible to provide a rice cooker that can prevent temperature unevenness and burnt rice due to reheating as much as possible.

[Brief explanation of the drawing]

Figures 1 to 9 show an embodiment of the present invention, Figure 1 is a circuit diagram without showing the electrical configuration, Figure 2 is a block diagram showing the electrical configuration, and Figure 3 is a schematic diagram of the rice cooker. 4 is a schematic explanatory diagram showing the corresponding positions of the mouths of the rice-cooking heater and the heat-retaining heater, FIG. 5 is a graph showing the relationship between elapsed time and detected temperature, and FIG. 6 is a diagram of the reheating process. Graph showing capacity detection and detection of reheating end state, Figure 7 is a circuit diagram showing a heater circuit for cooking rice, Figure 8 is a circuit diagram showing a heater circuit for keeping warm,
Fig. 9 is a circuit diagram showing a reheating heater circuit, Figs. 10 to 12 show other embodiments, Fig. 10 is a circuit diagram showing a large capacity heater circuit, and Fig. 11 is a circuit diagram showing a medium capacity heater circuit. FIG. 12 is a circuit diagram showing a small capacity heater circuit. 7... Rice cooking heater 8.9... Heat retention heater 11... Pot (container) 17... Rice (rice to be cooked) 18... Water (to be cooked) 20... Temperature detection means 21 ...Control means 27...Relay drive circuit (heater drive means) 32G.
...Reheating heater circuit patent Applicant: Toshiba Heat Appliances Co., Ltd. Agent: Patent attorney Ushiki Question: Patent attorney: Susuki 1) Chōshi
Buken Yomon Mail p□

Claims (1)

[Claims] A container for storing rice to be cooked, a rice cooking heater for heating the container, a moisturizing heater provided corresponding to the body of the container, a heater driving means, and a temperature detecting means for detecting the temperature of the container; and a control means for sequentially executing each process such as rice cooking and keeping warm, and this control means forms a reheating heater circuit mainly using the warming heater, which has a calorific value larger than that of the heater in the keep-warm process. A rice cooker characterized in that the rice cooker is capable of reheating by driving the reheating heater circuit.