JP5872400B2 - Thermal insulation equipment - Google Patents

Description

  The present invention relates to a heat retention device that retains a food at a temperature at which meals can be eaten.

  The texture of rice, which is one of the cooked items, is greatly influenced by the temperature, and the higher the temperature, the closer it is to freshly cooked, the taste is delicious. On the other hand, a rice cooker, which is one of the heat retaining devices, can be selected to increase (for example, 72 ° C.) or lower (for example, 65 ° C.) the execution temperature of the heat retaining process. And in the manufacturer of this kind of rice cooker, in order to save energy, the initial setting is set to a low heat retention, and the user also tends to use it with a low heat retention. However, since the length of time for keeping warm differs for each user, there is room for improvement in the warming method in order for the user to eat rice with good texture.

  Patent Document 1 describes a rice cooker that allows the execution time of heat insulation processing to be selected as “heat insulation long”, “heat insulation short”, and “no heat insulation” before execution of the rice cooking treatment. In this rice cooker, it is set as the structure which changes the heating amount at the time of execution of a rice cooking process according to the execution time of the selected heat retention process, and adjusts the moisture content of the cooked rice. That is, the water content at the end of the rice cooking process is adjusted based on the fact that the water that evaporates increases as the heat retention time increases.

  However, since the rice cooker of patent document 1 changes the heating amount in the rice cooking process based on the selected heat retention time, depending on the selected time, the rice cooker has a lot of water content, It becomes less hard rice, the cooked rice right after cooking is not constant, and it is not in an optimal state. In the first place, a user who uses a rice cooker eats cooked rice at the first desired time using the reserved rice cooking function, keeps the remaining rice warm, and eats at the second or third desired time. Therefore, changing the state of rice immediately after cooking rice gives the user a feeling of strangeness.

  Patent Document 2 describes a rice cooker that allows selection between normal heat retention and high temperature heat retention, and further allows the setting time of high temperature heat retention to be changed. In this rice cooker, when normal heat retention is selected, the temperature is lowered to the low temperature heat retention temperature after the end of the rice cooking process, and the low temperature heat retention temperature is maintained by the heating means. When high temperature heat retention is selected, the high temperature heat retention temperature maintained between 78 ° C. and 85 ° C. is changed according to the set execution time. Specifically, the heat retention temperature is lowered as the execution time becomes longer. And when the execution time of high temperature heat retention passes, normal heat retention will be performed.

  However, in the heat-retaining process of the rice cooker of patent document 2, when eating the rice cooked in the morning at night, since it is normally heat-retaining state, the food texture is getting worse. If the execution time of the high temperature heat retention can be set longer, the heat retention temperature is set lower as the execution time becomes longer, so that it does not change from the normal heat retention. Further, since the high temperature heat insulation is performed immediately after the start of the heat treatment, the moisture contained in the rice evaporates immediately, and the texture is remarkably deteriorated.

JP-A-7-95922 JP 2005-296538 A

  It is an object of the present invention to provide a heat retaining device that matches a user's lifestyle and can optimally maintain the heat retaining state of a cooked food within a selected heat retaining time.

In order to solve the above-described problems, the heat retaining device according to the present invention can cook the food in the inner pot disposed in the device main body by the heating means based on the detection value of the temperature detection means, and can eat the food. A warming device that keeps the temperature within the warming temperature zone, and is selected by the selection unit by controlling the heating unit and selecting means that can select a predetermined taste guarantee time out of two or more preset taste guarantee times. And a control means for executing different heat retention processes for each taste guarantee time.
If it does in this way, in the taste guarantee time which the user selected, deterioration of a cooking thing can be suppressed to the maximum and a favorable food texture can be maintained.

In this heat retaining device, the heat retaining treatment includes a low heat retaining step for retaining heat on the low temperature side of the heat retaining temperature zone and a high heat retaining step for retaining temperature on the high temperature side of the heat retaining temperature zone, and at least for each taste guarantee time. The execution time of the said low heat retention process differs. Here, the different execution times include “0 minutes” that is not executed. If it does in this way, evaporation of the water | moisture content of a foodstuff will be suppressed to the maximum, and the food texture including temperature can be maintained favorable at the end of the taste guarantee time at the time of a meal.
In this case, it is preferable to execute the high heat retention step after the low heat retention step. If it does in this way, it can prevent that the moisture contained in rice evaporates excessively.
Moreover, it is preferable that the said heat retention process lengthens the execution time of the said low heat retention process as the selected said taste ensuring time becomes long. If it does in this way, energy saving can be aimed at by the low heat retention process performed at the beginning, and good food texture can be ensured reliably by execution of the high heat retention process at the end.

A first set temperature on a high temperature side of the heat retention temperature zone; a second set temperature on a low temperature side of the heat retention temperature zone; and a third set temperature lower than the first set temperature and higher than the second set temperature. In the low heat retention step, the heating means is controlled based on the first and second preset temperatures, while in the high heat retention step, the heating means is controlled based on the first and third preset temperatures. It is preferable to do. If it does in this way, a low heat retention process and a high heat retention process can be performed reliably within a heat retention temperature range.
Specifically, in the low temperature keeping step, when the temperature reaches the first set temperature by heating, a temperature lowering step is performed to lower the temperature by lowering the amount of electric power supplied to the heating means, and when the temperature reaches the second set temperature, the heating means The temperature is adjusted so as to be maintained at the second set temperature by controlling on / off, and when the temperature adjustment step is executed for a predetermined time, a temperature raising step for increasing the temperature by increasing the amount of electric power supplied to the heating means is executed. Is preferred. In this way, even if the second set temperature is set to a low temperature at which high-temperature-grown bacteria and the like are likely to propagate, by setting the first set temperature to a high temperature that can suppress the growth of the bacteria, In addition to preventing deterioration of the cooked product, energy saving can be reliably achieved.
In this case, in the low temperature keeping step, the time until the temperature lowering step falls below the fourth set temperature that is higher than the third set temperature and lower than the first set temperature and exceeds the fourth set temperature by the temperature raising step. It is preferable to set the execution time (TK) of the temperature adjustment step so as to be equal to or less than a preset deterioration prevention time (TP). If it does in this way, degradation of a cooked item can be prevented reliably.
In the high temperature keeping step, when the temperature reaches the first set temperature by heating, a temperature lowering step is performed to lower the temperature by lowering the amount of power supplied to the heating means, and when the temperature reaches the third set temperature, the temperature is supplied to the heating means. It is preferable to execute a temperature raising step for raising the amount of electric power and raising the temperature. If it does in this way, the temperature which can obtain favorable food texture can be maintained reliably.
In addition, the electric energy supplied to a heating means means the total amount of electric power supplied until it becomes another specific preset temperature from a specific preset temperature. And lowering the amount of power to be supplied includes “0” in which energization is cut off.

Furthermore, it is preferable that the first set temperature is 75 ° C. or more, the third set temperature is less than 75 ° C. and 60 ° C. or more, and the second set temperature is less than 60 ° C. Here, the upper limit of the first set temperature is 95 ° C., and the lower limit of the second set temperature is 40 ° C. If it does in this way, after preventing proliferation of bacteria certainly, energy conservation is attained and the heat retention process which maintained favorable food texture is possible.
And it is preferable that the taste guarantee time selectable by the selection means has 12 hours, 24 hours, 48 hours, and 0 hours when the heat retention process is not performed. In this way, it is possible to provide a heat retaining device with good usability according to the user's lifestyle.

  In the heat insulation device of the present invention, the user can select the taste guarantee time, and performs different heat insulation processing for each selected taste guarantee time, so that the deterioration of the cooked product is suppressed to the maximum within the taste guarantee time, and good A good texture can be maintained. Therefore, it is possible to provide a heat retaining device with good usability that matches the lifestyle of the user. Specifically, after performing a low heat retention process that keeps the temperature low on the low temperature side of the heat retention temperature zone, and then performing a high heat insulation process that keeps the temperature warm on the high temperature side of the heat retention temperature range, in the early stage, the maximum evaporation of the moisture in the cooked food is performed. The food texture including temperature can be made good at the end of the meal.

It is the schematic which shows the rice cooker which is the heat retention apparatus of embodiment which concerns on this invention. It is a top view which shows an example of the operation panel of a rice cooker. It is a block diagram which shows the structure of a rice cooker. It is a graph which shows the execution time of the low heat retention process of each selectable taste ensuring time, and the high heat retention process. (A) is a time chart which shows an example of the heat retention process in the case of heat retention for half a day, (B) is heat retention for 1 day, and (C) is heat retention for 2 days. It is a flowchart which shows the heat retention process by a microcomputer. It is a flowchart which shows the low heat retention process of FIG. It is a flowchart which shows the high heat retention process of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1: shows the rice cooker which is an example of the heat retention apparatus of embodiment which concerns on this invention. This rice cooker includes a rice cooker body 11 that removably accommodates an inner pot 10 that is induction-heated, and a lid 19 that is attached to the rice cooker body 11 so as to be opened and closed. And in this embodiment, in the heat retention process which heats the rice which is a cooking thing, the user can select the desired heat retention time, and the heat retention state until that time has passed is made the most excellent. is there.

  The rice cooker main body 11 is provided with an opening 12 at the upper part of the exterior body, and on the lower side of the opening 12, an inner body 13 constituting a housing part of the inner pot 10 and a protective frame 14 made of a non-conductive material. Is arranged. An induction heating coil 15, which is a first heating means for induction heating the inner pot 10, is disposed below the outer peripheral surface of the protective frame 14 via a ferrite core 16. In addition, on the outer peripheral surface of the inner cylinder 13, a cylinder heater 17 that is a second heating means for heating the upper side of the inner pot 10 is disposed. Furthermore, the protective frame 14 is provided with a pan temperature sensor 18 which is a first temperature detecting means for detecting the temperature of the inner pan 10.

  The lid 19 is rotatably attached to the rice cooker body 11 and closes the opening 12 of the rice cooker body 11. In the lid body 19, a heat radiating plate 20 is disposed on the inner surface side facing the inner pot 10, and a lid heater 21 as a third heating means is disposed on the upper surface of the heat radiating plate 20. An inner lid 22 that seals the upper end opening of the inner pot 10 is detachably disposed on the lower surface of the heat radiating plate 20. Further, the lid 19 is provided with an exhaust passage 23 that communicates the inside of the inner pot 10 with the outside. Furthermore, the lid body 19 is provided with a lid temperature sensor 24 which is a second temperature detecting means for detecting the temperature in the inner pot 10 so as to be in contact with the heat radiating plate 20. In addition, the code | symbol 25 in a figure is an opening operation member for opening operation of the cover body 19. As shown in FIG.

  In this rice cooker, an operation panel unit 26 is provided on the front upper portion of the rice cooker main body 11 for the user to input rice cooking conditions and heat retention time or to display the current operation state. As shown in FIG. 2, the operation panel unit 26 is provided with a plurality of switches 27 to 34 as input means around a central liquid crystal display panel 35.

  On the right side of the liquid crystal display panel 35, rice cooking switch 27, which is a rice cooking process execution switch, up switch 28 and down switch 29 for changing the current time, rice cooking time, and the like, and rice at the first desired time to eat A reservation switch 30 which is a selection switch for reservation rice cooking for cooking is provided. Further, on the left side of the liquid crystal display panel 35, there is a barge switch 31 for stopping the rice cooking process and the heat retaining process or canceling the selection state, and a no-wash rice switch for selecting that the cooked rice is non-washed rice. 32 is provided. Below the non-washing rice switch 32 are a menu switch 33 for selecting a menu, and a selection means for selecting an execution time (taste guarantee time) TS of the heat retention process as well as a heat retention process execution switch. A heat retention selection switch 34 is provided.

  The liquid crystal display panel 35 is provided with a menu segment 37 indicating a selection state of a menu that can be cooked around a numerical value segment 36 that indicates a reservation time, a remaining time required for cooking, and the like. In addition, a triangular mark display section 38 that indicates the selected state of white rice and the setting state of the cooked hardness (five levels) is provided above the numerical value segment 36. Further, on the lower side of the liquid crystal display panel 35, a heat retention time (taste guarantee time) selection display section 39 that can be selected by operating the heat retention selection switch 34 is provided. This heat retention time selection display unit 39 indicates a selection state of the taste guarantee time TS, and is kept warm (no heat retention), half day (12 hours), one day (24 hours) and two days (48 hours). LED 40a-40d is arrange | positioned beside the character display.

  The rice cooker is provided with a control board 42 on the front side of the rice cooker main body 11 via a holder 41, and a microcomputer 43 as a control means is mounted on the control board 42. As shown in FIG. 3, the microcomputer 43 is preset in a ROM 44 that is a built-in storage unit based on input information by operating a switch on the operation panel unit 26 and input information from the temperature sensors 18 and 24. According to the program, the induction heating coil 15, the body heater 17, and the lid heater 21 are controlled to perform the rice cooking process and the heat retaining process.

  Specifically, the ROM 44 of the microcomputer 43 stores a different rice cooking flow (rice cooking process) and a heat retaining flow (heat retaining process) depending on each menu. When the rice cooking switch 27 is operated, after the selected rice cooking process is executed, the heat retaining process is subsequently executed. In addition, when the heat retention selection switch 34 is operated, the heat retention time (taste guarantee time) previously executed (selected) is turned on (selected), and “warming off”, “half-day warming”, and “daily warming” are performed each time the operation is performed. “Two-day heat retention” is selected in order. When the non-operation state continues for 3 seconds, the selected state is confirmed, and the selected heat retaining process is executed. Note that the initial setting is one-day heat retention.

  A rice cooking process has a preheating process, a temperature rising process, a boiling maintenance process, and an unevenness process similarly to a well-known rice cooker, and these processes are performed in order. The preheating step is for causing the rice to absorb water, and the induction heating coil 15 and the lid heater 21 are operated so that the lower measurement temperature by the pan temperature sensor 18 is maintained at about 40 ° C. In the temperature raising step, the temperature in the inner pot 10 is raised to a temperature just before boiling, and the rice cooking capacity in the inner pot 10 is determined in the middle of the heating, and the induction heating coil 15 and the lid heater 21 are operated at full power. . The boiling maintenance step is to cook the rice in the inner pot 10 at the boiling temperature and dry it up, and the induction heating coil 15, the trunk heater 17 and the lid heater 21 are on / off controlled at a predetermined energization rate. The unevenness process steams the cooked rice in the inner pot 10, and the induction heating coil 15, the trunk heater 17 and the lid heater 21 are operated at a predetermined energization rate.

  As shown in FIGS. 4 and 5 (A), (B), (C), the heat retaining process is performed by controlling the induction heating coil 15 and the lid heater 21 based on the detected value of the pan temperature sensor 18. The temperature of the rice in the inner pot 10 is kept in a temperature range where the meal can be eaten (55 ° C. to 80 ° C. in this embodiment). In this embodiment, a different heat retention process is executed for each taste guarantee time TS selected by the heat retention selection switch 34.

  Specifically, the heat retention process is configured by combining a low heat retention step and a high heat retention step within the selected taste guarantee time. Specifically, after the execution of the low temperature keeping process, the high temperature keeping process is subsequently executed. The low heat retention step is to heat the rice on the low temperature side of the heat retention temperature zone (average temperature is about 60 ° C.). The detected values of the temperature sensors 18 and 24 and the first and second preset temperatures T1 and T2 set in advance. The induction heating coil 15 is controlled based on the above. The high heat retention step is to heat the rice on the high temperature side (average temperature is about 70 ° C.) of the heat retention temperature zone, and the detected values of the temperature sensors 18 and 24 and the first and third preset temperatures T1 and T3 set in advance. The induction heating coil 15 controls based on the above.

  The execution time of the low heat retention step and the high heat retention step is set to be different based on the selected taste guarantee time TS, as shown in FIG. As shown in FIG. 4, the execution time of the low heat retention step is set to become longer as the selected taste guarantee time TS becomes longer. Here, as shown in the case of the half-day heat retention, the change in the execution time of the low heat retention step includes “0 minutes” that is not executed. Further, in the present embodiment, except when “Heat insulation cut” is selected, after the taste guarantee time TS that includes the low heat retention process and the high heat retention process has elapsed, the high heat insulation is maintained until the tear-off switch 31 is operated. It is set as the structure which continues performing a process.

  The first set temperature T1 is a temperature on the high temperature side of the heat retention temperature zone, and is set to a temperature at which a high-temperature cultivated bacterium (for example, Bacillus genus bacteria) that can be cultivated even during the heat insulation can be killed. The first set temperature is preferably less than 95 ° C. and 75 ° C. or more in order to prevent excessive evaporation of moisture, and is set to 80 ° C. in this embodiment. The second set temperature T2 is a temperature on the low temperature side of the temperature keeping temperature zone, and there is a possibility that high-temperature breeding bacteria and the like will propagate, but the growth rate is set to a low temperature. The second set temperature is preferably less than 60 ° C. and 40 ° C. or more in order to reduce power consumption, and is set to 55 ° C. in this embodiment. The third set temperature T3 is lower than the first set temperature T1 and higher than the second set temperature T2, and the average temperature with the first set temperature T1 is set to a temperature at which the breeding risk of the high-temperature-grown bacteria is low. The third set temperature is preferably less than 75 ° C. and 60 ° C. or more in order to make the texture of the average temperature good, and is set to 65 ° C. in this embodiment. If it does in this way, after preventing proliferation of bacteria certainly, energy conservation is attained and the heat retention process which maintained favorable food texture is possible.

  The low temperature keeping process is a process of repeatedly performing a temperature lowering step, a temperature adjusting step, and a temperature raising step. In the temperature lowering step, when the first set temperature T1 is reached by heating, the amount of electric power supplied to the induction heating coil 15 is lowered to lower the temperature of the rice. The amount of electric power means the total amount of electric power supplied to the induction heating coil 15 in the temperature lowering step. In this embodiment, the power supply to the induction heating coil 15 is cut off. That is, reducing the amount of power to be supplied includes “0” in which energization is cut off. Note that the temperature may be gradually lowered while power is periodically supplied. The temperature adjustment step is to maintain the rice at the second set temperature T2 for a predetermined time TK by performing on / off control of the induction heating coil 15 when the temperature reaches the second set temperature T2 due to the temperature drop. In the temperature raising step, the amount of electric power supplied to the induction heating coil 15 is increased to raise the temperature of the rice (reheating). In this embodiment, it is set as the structure which heats up by supplying electric power to the induction heating coil 15 with the maximum electricity supply rate which does not cause a burning to rice.

  The execution time TK of the temperature adjustment step is a deterioration prevention time TP that can achieve maximum energy saving in a low heat retention process with an average temperature of about 60 ° C., and can minimize the deterioration of rice. Is set based on Specifically, the risk of breeding high-temperature-growing bacteria increases as the temperature decreases with a temperature retention of about 70 ° C. as a boundary. In addition, the temperature-cultivated bacteria increase with time, and when it exceeds about 5 hours, the user can recognize the deterioration of cooked rice accompanying the increase in bacteria. Therefore, the fourth set temperature T4 is 70 ° C. higher than the third set temperature T3 and lower than the first set temperature T1. Then, the temperature adjustment step execution time TK is set so that the time until the temperature falls below the fourth set temperature T4 by the temperature lowering step and exceeds the fourth set temperature by the temperature increase step is equal to or shorter than the deterioration prevention time TP. In the present embodiment, the remaining amount of rice in the inner pot 10 is determined based on the temperature descending gradient by the temperature lowering step and the data table stored in advance in the ROM 44, and from the second set temperature T2 to the fourth set temperature by the temperature increasing step. The time required to raise the temperature to T4 is calculated, and the execution time TK of the temperature adjustment step is set. Of course, the execution time TK may be set in advance so as not to exceed the deterioration prevention time TP for all remaining amounts.

  The high temperature keeping process repeats a temperature lowering step and a temperature raising step. In the temperature lowering step, when the first set temperature T1 is reached by heating, the amount of electric power supplied to the induction heating coil 15 is lowered to lower the temperature. In the present embodiment, the electric power for the induction heating coil 15 is adjusted so that the temperature falls from the first set temperature T1 to the third set temperature T3 during the temperature drop time TD. In the temperature raising step, as in the case of the low temperature keeping step, the temperature of the rice is raised by increasing the amount of electric power supplied to the induction heating coil 15 so as not to burn the rice.

  The temperature lowering time TD of the temperature lowering step is set based on the growth preventing time TE that enables the growth of the high-temperature-grown bacteria in the high heat retention step in which the average temperature is about 70 ° C. Specifically, in order to prevent the growth of high-temperature-growing bacteria and to sterilize, it is preferable to raise the temperature of the rice to the first set temperature T1 every 6 hours. Therefore, the time required to raise the temperature from the third set temperature T3 to the first set temperature T1 is measured in the temperature raising step, and the temperature drop time TD is set by subtracting the measured time from the proliferation prevention time TE. Incidentally, in the human lifestyle, morning, noon, and night time periods for eating rice are approximately every 6 hours. Therefore, by raising the temperature to the first set temperature T1 every 6 hours, it is possible to eat rice at a temperature close to freshly cooked. Therefore, the proliferation prevention time TE (6 hours) is set so as to match the lifestyle of the user. Therefore, it is possible to execute a heat retaining process with good usability according to the lifestyle of the user. In addition, when the temperature is raised every 6 hours, the time that is lower than the fourth set temperature T4 is less than 5 hours, so that the risk of bacterial growth is also reduced.

  Next, the heat insulation process by the microcomputer 43 will be specifically described. In this heat retention process, the following steps S <b> 1 to S <b> 9 are executed until an interrupt stop process is executed by operating the take-off switch 31.

  When the rice cooking process is finished and the heat insulation process is executed, or when the user sets the cooked rice in the inner pot 10 and the heat insulation process is executed, as shown in FIG. In step S1, the built-in measurement timer 45 is reset and started, and the measurement of the heat retention time is started. Next, in step S2, the selected heat retention time is read. In step S3, the taste guarantee time TS is set, and in step S4, the execution time TL of the low heat retention process is set.

  Thereafter, in step S5, an execution time TL is measured in step S6 (parallel processing) while performing a low heat retention process described later. That is, the low heat retention process is executed until the execution time TL elapses.

  When the execution time TL of the low heat retention process elapses, the taste guarantee time TS is measured in step S8 while executing the high heat retention process described later in step S7 (parallel processing). Then, when the taste guarantee time TS has elapsed, in step S9, the high temperature keeping step in step S7 is continued while executing the notification process. In addition, although the notification process of this embodiment is set as the structure which blinks all LED40a-40d of a heat retention time display part, various methods, such as outputting a notification sound with a piezoelectric buzzer, are possible.

  In the low temperature keeping step of step S5, as shown in FIG. 7, first, in step S5-1, energization to the induction heating coil 15 is turned off (cut off), and the temperature lowering step is executed. Next, in step S5-2, after performing the remaining rice amount determining process in the inner pot 10 based on the temperature descending gradient, in step S5-3, the temperature adjustment step is performed based on the determined remaining rice amount. Set the execution time TK. Thereafter, in step S5-4, the process waits until the temperature detected by the pan temperature sensor 18 becomes lower than the second set temperature T2, and when the temperature reaches the second set temperature T2, the process proceeds to step S5-5 to execute the temperature adjustment step. .

  In step S5-5, after the induction heating coil 15 is turned on (energized), the process waits until the temperature detected by the pan temperature sensor 18 becomes equal to or higher than the second set temperature T2 in step S5-6. And when it becomes 2nd preset temperature T2 or more, after energization to induction heating coil 15 is interrupted at Step S5-7, it will be judged at Step S5-8 whether execution time TK passed. And when execution time TK has not passed, it returns to step S5-4 and repeats the temperature adjustment step from step S5-4 to S5-8. On the other hand, if the execution time TK has elapsed, the process proceeds to step S5-9 to execute the temperature raising step.

  In step S5-9, energization of the induction heating coil 15 is started, and in step S5-10, power adjustment processing is performed so that the temperature is raised in a range where the rice does not burn, and step S5-11. Thus, it is determined whether or not the temperature detected by the pan temperature sensor 18 is equal to or higher than the first set temperature T1. That is, the power adjustment process is executed until the temperature becomes equal to or higher than the first set temperature T1. And if it becomes more than 1st preset temperature T1, it will return to step S5-1 and will perform a temperature fall step.

  As described above, in the low temperature keeping step, the temperature lowering step from step S5-1 to step S5-4, the temperature adjusting step from step S5-4 to step S5-8, and the step from step S5-8 until the execution time TL elapses. The temperature raising step of S5-11 is repeatedly executed. And in this low heat retention process, although 2nd preset temperature T2 is set to the low temperature with which a high temperature breeding microbe etc. may breed, the 1st preset temperature is set to the high temperature which can suppress propagation of a microbe. doing. In addition, the execution time TK of the temperature adjustment step maintained at the second set temperature T2 is set based on the deterioration prevention time TP. Therefore, it is possible to surely prevent the rice from being deteriorated and to surely save energy.

  In the high heat retention step of step S7, as shown in FIG. 8, first, in step S7-1, the amount of electric power supplied to the induction heating coil 15 is increased and the temperature raising step is executed. Next, in step S7-2, the temperature rising measurement timer is reset and started in order to measure the execution time of the temperature raising step. Thereafter, in step S7-3, power adjustment processing is executed in the same manner as described above, and in step S7-4, it is determined whether or not the temperature detected by the pan temperature sensor 18 is equal to or higher than the first set temperature T1. And if it becomes 1st preset temperature T1 or more, at step S7-5, a temperature rising measurement timer will be stopped, and it will progress to step S7-6 and will perform a temperature fall step.

  In step S7-6, the amount of power supplied to the induction heating coil 15 is lowered so that the temperature in the inner pot 10 decreases, and then in step S7-7, the temperature lowering step execution (temperature lowering) time TD is set. Then, in step S7-8, while adjusting the electric energy supplied to the induction heating coil 15 so that it may fall to 3rd setting temperature T3 by execution time TD, in step S7-9, detection temperature by the temperature sensor 18 for pots Is less than the third set temperature T3. That is, the power adjustment process is executed until the temperature becomes lower than the third set temperature T3. And if it becomes less than 3rd preset temperature T3, it will return to step S7-1 and will perform a temperature rising step.

  As described above, in the high temperature keeping process, the temperature increasing step from step S7-1 to step S7-6 and the temperature decreasing step from step S7-6 to step S7-9 are repeatedly executed until the take-off switch 31 is operated. . For this reason, at the end of the heat-retaining process for the user to eat, the temperature at which a good texture can be obtained can be reliably maintained, and the growth of high-temperature-grown bacteria can be reliably prevented.

  In this way, in the rice cooker of the present invention, since different heat retention processes are performed for each taste guarantee time that is the heat retention time selected by the user, the deterioration of the rice is suppressed to the maximum within the selected taste guarantee time. Therefore, a good texture can be maintained. Specifically, the heat retention treatment suppresses the evaporation of the moisture of the rice to the maximum in the low heat retention process in the early stage, and the food texture including the temperature in the high heat retention process at the end of the meal is in a good state. can do. And since the execution time TL of a low heat retention process is lengthened as the selected taste guarantee time becomes long, energy saving can fully be aimed at. And since the rice cooking process has not changed at all, the food texture immediately after cooking is not impaired.

  In addition, this invention is not limited to the structure of the said embodiment, A various change is possible.

  For example, in the above-described embodiment, it has a low heat retention process and a high heat retention process, and the high heat retention process is performed after the low heat retention process. However, the intermediate temperature of the heat retention temperature zone is set before or after the low heat retention process. It is good also as a structure which performs the heat retention process during heat retention. Moreover, it is good also as a structure which performs a high heat retention process before a low heat retention process, if it is the execution time which is a grade which does not discharge | release moisture excessively from rice. And it is good also as a structure which performs a low heat retention process and a middle heat retention process after a high heat retention process.

  Furthermore, in the said embodiment, although it was set as the structure which does not perform a low heat retention process in the case of half day heat retention, it is good also as a structure which performs for 6 hours, for example. Furthermore, in the above embodiment, the temperature adjustment step is provided in the low heat retention process, but the temperature adjustment step is not provided as in the high heat insulation process, and hunting is performed between the first set temperature T1 and the second set temperature T2. It is good also as a structure to control. Moreover, although the low temperature keeping process and the high temperature keeping process are configured to repeatedly execute a cycle of raising the temperature to the first set temperature at which the high temperature cultivated bacteria can be killed in the temperature raising step, the first set temperature is lowered stepwise. It is good also as a structure which makes it raise or raises in steps.

  In the embodiment, the fourth set temperature T4 is a reference temperature at the time of design, and is not used for actual control by the microcomputer 43. However, from the time when the temperature falls below the fourth set temperature T4 in the temperature lowering step. You may comprise so that time measurement may be started and execution time TK of a temperature control step may be lengthened to the maximum. Moreover, it is good also as a structure which cools rapidly with a fan until it becomes 4th preset temperature T4 from 1st preset temperature T1 on condition that the time which falls below 4th preset temperature T4 is less than 5 hours.

  Moreover, in the said embodiment, although demonstrated using the induction heating type rice cooker which mounted the induction heating coil 15 as a heating means, a heater is arrange | positioned inside the board | plate material which consists of aluminum material with good heat conductivity as a heating means. The cooker which arrange | positioned the heated plate may be used. Furthermore, the pressure cooker which can arrange | position the relief valve which can interrupt | block communication with the inside of the inner pot 10 and the exterior in the exhaust passage 23, and can pressure-up the inside pot 10 to a pressure higher than atmospheric pressure may be sufficient.

  And although the rice cooker was mentioned and demonstrated in the said embodiment as an example, the same effect | action and effect can be acquired also as a heat retention apparatus carrying only a heat retention function. In this case, the object to be kept warm is not limited to rice, and similar actions and effects can be obtained even if the food is a cooked dish such as a side dish.

10 ... inner pot 11 ... rice cooker body (equipment body)
15 ... induction heating coil (heating means)
17 ... Body heater (heating means)
18 ... Pan temperature sensor (temperature detection means)
21 ... Lid heater (heating means)
24. Temperature sensor for lid (temperature detection means)
26 ... Operation panel 27-33 ... Rice cooking switch 34 ... Insulation selection switch (selection means)
35 ... Liquid crystal display panel (display means)
39 ... Insulation time (taste guarantee time) selection display part 40a-40d ... LED
43 ... Microcomputer (control means)
44 ... ROM (storage means)

Claims (6)

A heat-retaining device that heats the cooked food in the inner pan disposed in the apparatus body by a heating means based on the detection value of the temperature detection means, and keeps the food in a heat-retaining temperature zone where meals can be eaten,
A selection means capable of selecting a predetermined taste guarantee time among two or more preset taste guarantee times;
Control means for controlling the heating means to perform different heat retention processes for each taste guarantee time selected by the selection means;
Equipped with a,
The heat retaining treatment includes a low heat retaining step for retaining the temperature on the low temperature side of the heat retaining temperature zone,
A high heat-retaining step for keeping warm on the high temperature side, and at least the low heat-retaining step for each taste guarantee time
The execution time of
A first set temperature on the high temperature side of the heat retention temperature zone; and a second set temperature on the low temperature side of the heat retention temperature zone;
Setting a third preset temperature lower than the first preset temperature and higher than the second preset temperature;
In the low temperature keeping step, the heating means is controlled based on the first and second set temperatures.
On the other hand, in the high temperature keeping step, the heating means is controlled based on the first and third set temperatures.
Heat insulation device according to claim to Rukoto. In the low temperature keeping step, when the temperature reaches the first set temperature by heating, a temperature lowering step is performed to lower the temperature by lowering the amount of power supplied to the heating means, and when the temperature reaches the second set temperature, the heating means is controlled to be turned on / off. The temperature is adjusted so as to be maintained at the second set temperature, and when the temperature adjustment step is executed for a predetermined time, a temperature raising step for increasing the temperature by increasing the amount of electric power supplied to the heating means is executed. Item 1. The heat retaining device according to item 1 . In the low temperature keeping step, a time until the temperature lowering step is lower than a fourth set temperature higher than the third set temperature and lower than the first set temperature by the temperature lowering step and exceeds the fourth set temperature by the temperature raising step is set in advance. The heat retention device according to claim 2 , wherein an execution time (TK) of the temperature adjustment step is set to be equal to or less than a deterioration prevention time (TP). In the high temperature keeping step, when the temperature reaches the first set temperature by heating, a temperature lowering step is performed to lower the temperature by lowering the amount of power supplied to the heating means, and when the temperature reaches the third set temperature, the amount of power supplied to the heating means. thermal insulation apparatus according to any one of claims 1 to 3, characterized in that to perform the Atsushi Nobori step of raising the temperature by raising the. Wherein the first set temperature is 75 ° C. or higher, the third set temperature is 75 ° C. below and 60 ° C. or higher, according to claim 1 to claim wherein the second predetermined temperature and less than 60 ° C. 5. The heat retaining device according to any one of 4 above. Taste guaranteed time selectable by said selection means, 12 hours, 24 hours, according to any one of claims 1 to 5, characterized in that it has a zero time is not executed for 48 hours and the heat retaining Insulation equipment.

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