JPH06304062A - Heating control method for rice cooker - Google Patents

Abstract

PURPOSE:To cook a tasty rice with a fixed quality by reducing the temperature of the inside of an inner pot gradually while heating an electric heater, when a main cooking process is transferred to a steaming process. CONSTITUTION:When a main cooking process is completed, and a gas burner B is extinguished, an electric heater H is turned ON right after that. Then, while an inner pot 20 is slightly heated, the temperature of the inner pot 20 is gradually lowered to a steaming temperature. First, a detected temperature of a temperature sensor 5 is stored as a reference temperature S, and a waiting for one second is done. Then, a temperature difference between the detected temperature of the temperature sensor 5 and the reference temperature S is compared with a proper descending temperature K which is separately determined, and when the temperature difference of the former is small, the calorific value of the electric heater H is lowered to promote the temperature reduction in the inner pot 20. When the temperature difference is at the proper descending temperature K or higher, it is judged whether the temperature difference and the proper descending temperature K are equal or not, and when those two are not equal, the calorific value of the electric heater is increased, the temperature of the inside of the inner pot 20 is prevented from decreasing suddenly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating control method for a gas rice cooker of the type in which rice is cooked while the electric heater is appropriately heated even when the rice is cooked other than heat retention. During the transition from the main cooking process to the subsequent steaming process, the cooked rice having a good taste is cooked by decreasing the temperature in the pot while maintaining a uniform temperature regardless of the place.

[0002]

2. Description of the Related Art A gas burner and an electric heater are selectively operated so that the temperature inside the kettle rises rapidly at the start of a heating operation and the temperature inside the kettle is maintained constant ( As a rice cooker that enables delicate temperature control when adjusting temperature, etc.)
The invention of No. 246915 was proposed.

The rice cooker is equipped with a gas burner for heating the inner pot and an electric heater and a temperature sensor for detecting the temperature in the inner pot. During the rice cooking operation, a preheating step arranged in time series as shown in FIG. 4 ( S1), main cooking process (S2), steaming process (S3),
And the heat retention step (S4) is performed in this order. In the preheating step (S1), the heating operation by the gas burner is first performed to raise the temperature in the inner pot (monitored by the temperature sensor) to 40 ° C., then the gas burner is extinguished and the electric heater is heated. Then, the temperature in the inner pot is maintained at 40 ° C. for a certain period of time.

In the main cooking step (S2), the temperature in the inner pot is from about 40 ° C. to about 145 ° C. (hereinafter referred to as the main cooking end temperature).
Keep the gas burner in combustion until it rises to. In the steaming step (S3), the gas burner is maintained in a fire extinguishing state,
When the temperature in the inner pot drops to about 98 ° C. (hereinafter referred to as the steaming temperature), the electric heater is turned off by 0N to maintain the steaming temperature in the inner pot for about 15 minutes.

Finally, in the heat retaining step (S4), the temperature in the inner pot is maintained at about 71 ° C to 72 ° C by the electric heater. In this case, in the initial stage of the preheating step (S1) and the like, the inner pot can be heated by the gas burner with a large calorific value,
In the steaming step (S3) and the like, in which the temperature inside the inner pot can rise quickly in the initial stage of heating, and a delicate temperature control is required, heating the inner pot with an electric heater provides high accuracy. Temperature control is possible.

However, in the above-mentioned conventional one, there is a problem that the cooked state of the rice in the central portion of the inner pot and the rice in the vicinity of the outer wall vary and the cooked rice cannot be cooked as a whole. . The above problems will be described in more detail. When the main cooking step (S2) is completed in the above conventional one, both the combustion operation of the gas burner and the heat generation operation of the electric heater are completely stopped until the temperature in the inner pot drops to the steaming temperature. Therefore, when the temperature drops, the temperature of the rice near the wall surface of the inner pot that comes into contact with the outside air decreases before the rice located in the center of the inner pot, and the temperature inside the inner pot gradually decreases from the center to the outer wall. Has become. That is, the conditions for pregelatinization of rice, which are closely related to temperature, are not uniform in the central portion inside the inner pot and the outside thereof. In particular, when the temperature of the outer wall of the inner pot sharply drops, the so-called overshoot at the time of the temperature drop causes the rice near the wall of the inner pot to cool further than the steaming temperature. Conversion stops. Then, in this case, the conditions for gelatinization of rice are more significantly different between the central portion of the inner pot and the outside thereof. For these reasons, in the above-mentioned conventional one, the taste of each rice grain cooked at each place in the inner pot varies, and the cooked rice cannot be cooked as a whole.

The present invention has been made in view of the above-mentioned points, and uses a rice cooker equipped with a gas burner and an electric heater for heating the inner pot, and a temperature sensor for detecting the temperature in the inner pot. Execute the main cooking process (S2) of heating the inner pot with the gas burner until the detected temperature reaches the final cooking temperature.
After that, in the heating control method of the rice cooker that controls the temperature inside the inner pot so that the temperature detected by the temperature sensor is maintained at a steaming temperature lower than the main cooking end temperature, the steaming step from the main cooking step (S2) When the rice cooking process shifts to (S3), the temperature inside the inner pot is lowered while maintaining an almost constant temperature regardless of the location, so that the cooked rice cooked in the center of the inner pot is cooked near the outer wall. The task is to ensure that cooked rice is evenly cooked.

[0008]

[Technical Means] The technical means of the present invention for solving the above-mentioned problem is that "the rice cooking process is the main cooking process (S2) to the steaming process.
At the time of shifting to (S3), the temperature of the inside of the inner pot is gradually lowered while heating the electric heater. ”

[0009]

The above technical means operates as follows. When the main cooking process (S2) is completed and the process proceeds to the steaming process (S3), that is, when the temperature in the inner pot is lowered to the steaming temperature, the electric heater heats up. As a result, the temperature gradient in the vicinity of the outer wall becomes small, and the temperature of the rice located in each part of the inner pot becomes almost uniform regardless of the location in the inner pot. That is, at the time of shifting from the main cooking step (S2) to the steaming step (S3), the temperature in the inner pot decreases while maintaining a uniform temperature.

[0010]

[Effect] The present invention has the following unique effects. The temperature of the cooked rice in the inner pot decreases while maintaining a substantially uniform temperature, so the rice cooked at each location in the inner pot progresses evenly, and delicious cooked rice with consistent quality is cooked. To be

When actually performing the steaming step (S2) for steaming the inside of the inner pot, the operation of intermittently heating the inner pot is continued for a predetermined time from the end of the main cooking step (S2). Let That is, the lower limit temperature (usually 96 ° C) for steaming inside the inner pot
When the temperature of the inner pot is lowered to 0 ° C, the inner pot is heated, and when the temperature is raised to the upper limit temperature (usually 98 ° C), the heating operation is stopped, and this heating and heating stop operation are repeated to repeat the heating operation. Is heated intermittently. However, when the temperature is adjusted, the inside of the inner pot is steamed and the upper limit temperature is 98%.
When the temperature is lowered to below ℃, the gelatinization of rice is delayed, which causes the taste of cooked rice to be deteriorated. On the other hand, according to the above technical means, since the temperature inside the inner pot is gradually lowered, the temperature control time for intermittently heating the inside of the inner pot is shortened, and the inside of the inner pot is correspondingly heated to the upper limit of steaming. The frequency of temperature drop below the temperature decreases. That is, according to the above technical means, it is possible to prevent the inconvenience that the temperature of the inside of the inner pot is frequently lowered and the gelatinization of rice is delayed, and the taste of cooked rice can be improved also from this point.

[0012]

Embodiments of the present invention described above will now be described with reference to the drawings. In the rice cooker of the embodiment shown in FIG. 1, the inner pot (20)
An operation switch (35) is provided on the top surface of the auxiliary chamber (31) on the front side of the main body case (2) for accommodating
A gas valve device (33) for supplying gas to a gas burner (B) described later is arranged at the bottom of the (31).

An inner pot that can be taken out freely from the body case (2)
(20), a heat insulating heat insulating cylinder (25) surrounding the outer periphery thereof, and a gas burner (B) for heating the inner pot (20) from below are housed. The heat insulating heat-insulating body (25) is mounted on the body of a bottomed inner case (2a) having a size capable of accommodating the inner pot (20), and the flame burner (B1) of the gas burner (B). ) Is this case
It projects into the inner case (2a) from an opening (24) formed at the bottom of the (2a) and faces the bottom of the inner pot (20). Also, this flame hole
An annular electric heater (H) is concentrically arranged on the outer periphery of (B1), and its connection terminal portion projects downward from the bottom of the inner case (2a). An ignition device (4) for igniting the gas burner (B) is provided near the gas burner (B), and a temperature sensor (5) for detecting the temperature of the kettle is provided on the bottom of the inner kettle (20).
Is attached. Then, the temperature sensor (5), the electric heater (H), the gas valve device (33), and the operation switch (3
Electrical components such as 5) are electrically connected to the control device (C) that incorporates a microcomputer.

Further, as shown in the figure, an openable / closable lid (6) is pivotally supported above the main body case (2), and in the closed state, the front of the lid (6) is opened. The structure is such that the engagement piece (6a) provided at the end portion is locked to the engagement body (6b) protrudingly provided at the front upper end portion of the main body case (2). Then, by operating the engagement piece (6a) to release the lock device, the lid body (6) is opened with the rear end portion as a fulcrum.

A control program having the contents shown in the flow chart of FIG. 2 is stored in the microcomputer constituting the control device (C), and when the rice cooking operation is executed in accordance with the program, the control shown in FIG. 3 is performed. It's made for you. Hereinafter, the operation of the rice cooker will be described with reference to FIGS. First, in step (70), switch (35)
When the operation switch (35) is operated, steps (71) to (73) are executed to turn on the gas burner (B).
Burn for 0 seconds only. As a result, as shown in FIG. 3, the temperature in the inner pot (20) rises quickly in the initial stage (S11) of the preheating step (S1). The ignition of the gas burner (B) is performed by opening the gas valve device (33) and driving the ignition device (4).

When the gas burner (B) is extinguished, the step (74) waits for 180 seconds to allow the heat accumulated in the wall of the inner pot (20) to completely disappear in the inner pot (20). After the gas burner (B) is kept in the extinguished state, step (75) is executed to maintain the inside of the inner pot (20) at about 40 ° C. for 14 minutes with the electric heater (H). That is, the temperature sensor (5)
Electric heater while monitoring the temperature in the inner pot (20) detected by
The amount of heat generated by (H) is controlled to maintain the inside of the inner pot (20) at 40 ° C.

Next, steps (76) and (77) are executed with the electric heater (H) kept in the OFF state until the temperature detected by the temperature sensor (5) reaches 115 ° C., that is, the inner pot (20 The gas burner (B) is burned until the water in () evaporates. Then, in step (79), a wait of 30 seconds is executed and the inner pot (2
Wait for the heat stored in the wall of (0) to completely diffuse inside.

Next, the steps (80) to (82) are executed until the temperature in the inner pot (20) detected by the temperature sensor (5) reaches 145 ° C. (main cooking end temperature). Burn,
This completes the main cooking step (S2). When the main cooking step (S2) ends, the steaming step (S3) starts. still,
The control of the process portion from the main cooking process (S2) to the steaming process (S3) is the subject of the present invention.

The gas burner after the above-mentioned main cooking step (S2) is completed
When (B) is extinguished, immediately after that, step (83) is executed to turn on the electric heater (H). Then, by heating the inner pot (20) slightly by the control described later, the temperature of the inner pot (20) is gradually lowered to the steaming temperature described later. In the step (83), the operation of setting the steaming timer T for measuring the steaming time to "0" is also executed.

Next, the control for gradually lowering the temperature of the inner pot (20) to the steaming temperature while slightly heating the inner pot (20) will be specifically described. First, in step (84), the temperature detected by the temperature sensor (5) is stored as a reference temperature (S), and in step (85), a waiting time of "1 second" is performed. Then in step (86),
The temperature difference between the temperature detected by the temperature sensor (5) and the reference temperature (S) (the temperature detected by the temperature sensor (5) one second before), and the separately determined appropriate temperature drop (K) (for example, 0.06deg). The degree of heat generation of the electric heater (H) is reduced in step (87) if the former temperature difference is small. This allows the inner pot (2
Promote the temperature decrease in 0). On the other hand, if the temperature difference is equal to or higher than the appropriate temperature drop (K), then in step (88) it is determined whether the temperature difference is equal to the appropriate temperature drop (K). (When the temperature difference between the temperature detected by (S) and the temperature sensor (5) exceeds the proper temperature drop (K))
Increases the amount of heat generated by the electric heater (H), which prevents the temperature inside the inner pot (20) from dropping sharply.

As described above, by executing the steps (86) to (89), the temperature in the inner pot (20) is lowered at a speed suitable for the predetermined appropriate lowered temperature (K). Next, in step (90), the temperature detected by the temperature sensor (5) is 95 as the lower limit of the steaming temperature (95 ° C. to 98 ° C. in this embodiment).
It is judged whether or not the temperature has dropped below ℃, and when the temperature is 95 ℃ or higher, the above-mentioned steaming timer T (timer set to "0" at the start of the steaming step (S3) to measure the steaming time) is set to 1
It is determined whether 5 minutes have passed (step (91)). Then, if 15 minutes has not passed, the step (8
Perform steps 4) to 90) and detect the temperature sensor (5) in the inner pot (20).
The temperature inside is 95 in the unit of the proper falling temperature (K) per unit time.
The heating value of the electric heater (H) is controlled so that the temperature drops to ℃.

Then, when the temperature detected by the temperature sensor (5) falls below 95 ° C. until the output of the steaming timer T reaches the steaming time of 15 minutes, steps (92) to (97) are executed, Until the output of the steaming timer T reaches 15 minutes, the temperature in the inner pot (20) is maintained within the range of 95 ° C to 98 ° C while turning on / off the electric heater (H). That is, when the temperature detected by the temperature sensor (5) for monitoring the temperature in the inner pot (20) becomes 98 ° C or higher, the process proceeds from step (93) to step (95) to turn off the electric heater (H), while When the temperature detected by the temperature sensor (5) drops to 95 ° C., the process proceeds from step (96) to step (92) to heat the electric heater (H). Then, during the ON / OFF operation of this electric heater (H), the output of the steaming timer T becomes 15 minutes in steps (94) (97).
To monitor. When the output of the steaming timer T reaches 15 minutes, the steps (94) to (9)
8) Or the process proceeds from step (97) to step (99), whereby the steaming step (S3) is completed.

Steps (98) to (101) show the control operation of the heat retention step (S4). If it is judged in step (99) that the temperature detected by the temperature sensor (5) has dropped below 71 ° C, the electric heater (H) is turned on in step (100), while
When it is confirmed in step (101) that the temperature detected by the temperature sensor (5) has reached 72 ° C. or higher, the electric heater (H) is turned off in step (98). Then, while turning on / off the electric heater (H) in this way, the temperature in the inner pot (20) (detection temperature of the temperature sensor (5)) is 71 ° C to 72 ° C.
Keep it to keep the cooked rice warm.

In the above embodiment, the temperature in the inner pot (20) is gradually decreased while controlling the heat generation amount of the electric heater (H). However, when the main cooking step (S2) is completed, After supplying a predetermined current (constant current) to the electric heater (H) and maintaining this state for a predetermined time (for example, 10 minutes), the electric heater (98) is turned on and off while the inner pot (20) is being held. The temperature may be adjusted to the steaming temperature.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rice cooker embodying the present invention.

FIG. 2 is a flowchart showing the control operation of the embodiment of the present invention.

FIG. 3 is a graph showing the temperature detected by the temperature sensor (5) in the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 (5) ・ ・ ・ Temperature sensor (20) ・ ・ ・ Inner pot (B) ・ ・ ・ Gas burner (H) ・ ・ ・ Electric heater

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michiru Shimotake 4-12 1-2 Hirano-cho, Chuo-ku, Osaka City Osaka Gas Co., Ltd.

Claims (1)

[Claims] 1. A rice cooker equipped with a gas burner and an electric heater for heating the inner pot and a temperature sensor for detecting the temperature in the inner pot is used, and the gas burner is used until the temperature detected by the temperature sensor reaches the final cooking temperature. A heating control method for the rice cooker that executes the main cooking step (S2) of heating the kettle and then adjusts the temperature inside the inner kettle so that the temperature detected by the temperature sensor is maintained at a steaming temperature lower than the final cooking end temperature In the above, the heating control method of the rice cooker is such that when the rice cooking process shifts from the main cooking process (S2) to the steaming process (S3), the temperature of the inside of the inner pot is gradually lowered while heating the electric heater.