JP2014180436A - Heat-insulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damaging deliciousness by excessive heating.SOLUTION: A heat-insulating device includes: first heating control means (microcomputer) for controlling heating means so as to let a detection value of temperature detection means keep an adjustment temperature Tk of a lower limit; second heating control means (microcomputer) for controlling the heating means so as to let a detection value of the temperature detection means rise to a heating target temperature Tt of an upper limit; time-measuring means for measuring a time when a temperature is below a reference temperature Tc higher than the adjustment temperature Tk and lower than the heating target temperature Tt; and heat insulation control means (microcomputer) for adjusting to the adjustment temperature Tk and raising a temperature to the heating target temperature Tt when a measured time with the time-measuring means becomes a temperature rise starting time th.

Description

  The present invention relates to a heat retaining device that retains food in a predetermined heat retaining temperature range.

  Patent Document 1 describes a rice cooker that is one of heat retaining devices and a heat retaining method thereof. This rice cooker heats the cooked rice at 70 ° C. after the completion of rice cooking, and raises the temperature within a range of 80 to 110 ° C. for a predetermined time when the first temperature rise start time (6 to 8 hours) has elapsed from the start of heat keeping. Thereby, yellowing of the cooked rice during the heat insulation is prevented, and the growth of bacteria that cause a strange odor is prevented, so that the taste of the cooked rice can be maintained. Moreover, in patent document 1, when the 2nd temperature rising start time (4 hours) passes after temperature rising is completed, it heats up again, and changes temperature rising time according to the rice cooking capacity discriminate | determined at the time of rice cooking. Is described.

  However, the temperature of cooked rice during heat retention is less likely to decrease as the capacity increases, and is more likely to decrease as the capacity decreases. Therefore, like the rice cooker of patent document 1, when performing temperature rising whenever the set temperature rising start time passes, the time which heat-retains at low temperature becomes short, so that there is much capacity | capacitance. And when time to heat-retain at low temperature is short, there exists a problem that the water | moisture content of cooked rice will be discharge | released by excessive heating and a deliciousness will be impaired.

JP 2001-37635 A

  This invention makes it a subject to provide the heat retention apparatus which can prevent that the taste of food is impaired by excessive heating.

  In order to solve the above-described problems, the heat retaining device of the present invention is a heat retaining device that heats food in the device body by a heating unit based on the detection value of the temperature detecting unit, and maintains the temperature in a heat retaining temperature zone corresponding to the food. A first heating control means for controlling the heating means so that a detection value of the temperature detection means maintains a temperature control temperature that is a lower limit of the temperature keeping temperature zone, and a detection value of the temperature detecting means is the temperature keeping temperature zone. A second heating control means for controlling the heating means so as to raise the temperature to an upper limit heating target temperature, and a detection value of the temperature detection means is lower than a reference temperature higher than the temperature control temperature and lower than the heating target temperature. When the temperature is adjusted to the temperature adjustment temperature by the first heating control means and the temperature measurement time by the time measurement means becomes the temperature rise start time, the heating target temperature is determined by the second heating control means. Ma Comprising a heat keeping control means for raising the temperature, the. Here, the reference temperature is a critical temperature (for example, 70 ° C.) that greatly affects the propagation of bacteria. In the case where the food is cooked rice, when the cooked rice temperature is lower than the reference temperature, the occurrence of yellowing can be suppressed, but the possibility that the bacteria will grow increases. On the other hand, when the cooked rice temperature is higher than the reference temperature, the possibility of yellowing increases, but it is possible to suppress the growth of bacteria.

  This heat retaining device executes the temperature increase by the second heating control means when the measurement time after the detection value of the temperature detection means falls below the reference temperature becomes the temperature increase start time, not every set temperature increase start time. To do. For this reason, the rate of temperature reduction of the cooked rice temperature varies depending on the heat retention amount, but in the present invention, the temperature adjustment time by the first heating control means can be made substantially constant regardless of the heat retention capacity. Therefore, since the excessive heating accompanying shortening of temperature control time can be suppressed, the water | moisture content release from a foodstuff can be suppressed and it can prevent that deliciousness is impaired.

  The apparatus body further includes a lid that closes the device main body so as to be openable, and a lid state detection unit that detects an open state of the lid, and the heat retention control unit opens the lid by the lid state detection unit. When detected, it is preferable to correct the temperature rise start time. Specifically, it is preferable that the heat retention control unit measures the opening time of the lid body, and shortens the temperature rise start time when the cumulative opening time exceeds the determination time. When the lid is opened, germs in the air may enter the device body. Further, when the lid is opened and the food in the apparatus main body is taken out by the cooking utensil, the bacteria attached to the cooking utensil adhere to the food in the apparatus main body. Therefore, when the lid is opened beyond the determination time, the temperature rise start time is shortened and the temperature adjustment time is shortened, so that the proliferation of the invading bacteria can be suppressed and the bacteria can be sterilized.

  In this case, when the temperature increase is executed by the second heating control unit, the heat retention control unit resets the accumulated time. In this way, it is possible to sterilize the bacteria that have invaded by opening the lid while suppressing excessive heating of the food in the device body, and reliably suppress the growth of the bacteria.

  Moreover, the said heat retention control means detects the fall temperature while the said cover body is open | released by the said temperature detection means, and when the fall temperature is larger than 1st determination temperature, the said temperature increase start time is shortened. In this way, it is possible to sterilize the bacteria that have invaded by opening the lid while suppressing excessive heating of the food in the device body, and reliably suppress the growth of the bacteria.

  Further, the temperature keeping control means detects the temperature when the lid is opened by the temperature detecting means, and does not shorten the temperature rise start time when the detected value is higher than the second determination temperature equal to or higher than the reference temperature. . When the food is below the reference temperature (temperature controlled state) when the lid is opened, the growth of the invading bacteria is promoted due to the temperature drop due to the intrusion of the outside air. Conversely, if the food is higher than the reference temperature, it will die even if bacteria enter. And when the detection value is higher than the second determination temperature when the lid is opened, since the temperature rise start time is not corrected, it is possible to reliably prevent overheating of the food and prevent the taste from being lost. .

  Moreover, it is preferable to further comprise a temperature lowering control means for lowering the temperature with a gentle downward gradient after the heating by the second heating control means than when the heating means is stopped. In this way, it is possible to secure a time in a temperature zone where sterilization is possible, and thus it is possible to reliably suppress the growth of bacteria.

  In the heat retaining device of the present invention, when the measurement time after the detected value falls below the reference temperature becomes the temperature rise start time, the temperature rise by the second heating control heating means is executed. Time can be made substantially constant. Therefore, since excessive heating of food can be suppressed, excessive water release from food can be suppressed and deliciousness can be prevented from being impaired.

Schematic which shows the rice cooker which is the heat retention apparatus of embodiment which concerns on this invention. The block diagram which shows the structure of a rice cooker. (A) is the conventional heat retention control, (B) is a conceptual diagram which shows the heat retention control of this invention. (A), (B) is a time chart which shows an example of the heat retention control of this invention. The flowchart which shows the heat retention process by a microcomputer. The flowchart which shows the temperature rising start time correction process processed in parallel at the time of a heat retention process. FIG. 6B is a flowchart continued from FIG. 6A.

  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 16 that is attached to the rice cooker body 11 so as to be opened and closed. Regardless of the remaining amount of cooked rice that is food, the rice cooker of the present embodiment adjusts the temperature rising start time that is executed during the heat-retaining process, thereby preventing overheating and reducing the taste. To prevent.

  The rice cooker main body 11 includes an accommodating portion 12 that accommodates the inner pot 10. An induction heating coil 13, which is a first heating means for induction heating the inner pot 10, is disposed below the outer peripheral surface of the housing portion 12. In addition, a barrel heater 14 as a second heating means for heating the upper portion of the inner pot 10 is disposed at the center of the outer peripheral surface of the housing portion 12. Furthermore, the container 12 is provided with a pan temperature sensor 15 which is a first temperature detecting means for detecting the temperature of the cooked rice inside through the inner pan 10.

  The lid 16 is rotatably attached to the rice cooker body 11 and closes the upper end opening of the inner pot 10 so as to be openable. A heat radiating plate 17 is disposed on the inner side of the lid 16 facing the inner pot 10, and a lid heater 18 as third heating means is disposed on the upper surface of the heat radiating plate 17. An inner lid 19 that seals the upper end opening of the inner pot 10 is detachably disposed on the lower surface of the heat radiating plate 17. An exhaust passage 20 that communicates the inside of the inner pot 10 with the outside is provided inside the lid body 16. Further, a lid temperature sensor 21 serving as second temperature detecting means for detecting the temperature in the inner pot 10 through the heat radiating plate 17 is provided.

  At the front upper part of the rice cooker body 11, an operation panel unit 22 is provided for the user to input rice cooking conditions and to display the current operation state and selection state. As shown in FIG. 2, the operation panel unit 22 includes a plurality of switches 23 as input means and a liquid crystal display plate 24 as display means.

  A lid opening / closing sensor 25 is provided as lid state detecting means for detecting the opened state of the lid body 16. The lid open / close sensor 25 of the present embodiment is a photo interrupter that is a non-contact sensor disposed on the upper part of the rice cooker body 11 on the hinge connection part side. The photo interrupter includes a light emitting unit and a light receiving unit that are arranged to face each other. When a shielding member disposed on the lid 16 enters between the light emitting unit and the light receiving unit, the light reception to the light receiving unit is blocked, and the signal is input to the microcomputer 28 to determine the closed state of the lid 16. it can. The lid opening / closing sensor 25 is not limited to a photo interrupter, and may be a distance measuring sensor that can determine the presence / absence of an object at a facing portion by receiving infrared light and receiving reflected light. Moreover, since the temperature of the inner pot 10 and the cover body 16 falls by opening of the cover body 16, the temperature sensors 15 and 21 can also be used.

  A control board 27 is disposed on the front side of the rice cooker body 11 via a holder 26, and a microcomputer 28 is mounted on the control board 27. The microcomputer 28 which is a control means incorporates a ROM 29 which is a storage means, and a program for executing the rice cooking process and the heat retaining process is stored in the ROM 29. The microcomputer 28 has a built-in measurement timer 30 for measuring elapsed time and the like.

(Cooking rice processing)
The rice cooking process has a preheating process, a temperature raising process, a boiling maintenance process, and a spotting process, as in the known rice cooker, and these processes are executed in order by the microcomputer 28. In the preheating step, the induction heating coil 13 and the lid heater 18 are operated so that the detected value Td by the pan temperature sensor 15 is maintained at about 40 ° C., and the rice rice absorbs water. In the temperature raising step, the induction heating coil 13 is operated at full power, and the temperature in the inner pot 10 is raised to a temperature just before boiling. Due to the temperature rise gradient when the detection value Tu of the lid temperature sensor 21 is raised from the first set temperature Ts1 (for example, 40 ° C.) to the second set temperature Ts2 (for example, 60 ° C.) during this temperature raising process, The cooking rice capacity in 10 is discriminated. In the boiling maintenance process, the induction heating coil 13, the body heater 14 and the lid heater 18 are on / off controlled at a lower energization rate (for example, 50%) than the temperature raising process, and the inside pan 10 is maintained at the boiling temperature to cook rice. . In the unevenness process, the induction heating coil 13, the body heater 14 and the lid heater 18 are operated at a lower energization rate (for example, 5%) than the boiling maintenance process, and the cooked cooked rice in the inner pot 10 is steamed.

(Insulation treatment)
The heat retention process is subsequently performed after the rice cooking process is completed. Alternatively, it is executed when the heat retention switch is operated in a standby state where no processing is executed. In this heat retention process, the microcomputer 28 controls the induction heating coil 13, the body heater 14 and the lid heater 18 based on the detection value Td of the pan temperature sensor 15, and a heat retention temperature zone in which cooked rice can be eaten (in this embodiment). 60 ° C to 80 ° C). The microcomputer 28 has a temperature control temperature Tk (for example, 60 ° C.) that is the lower limit value of the heat retention temperature zone, a heating target temperature Tt (for example, 80 ° C.) that is the upper limit value, and is higher than the temperature control temperature Tk and lower than the heating target temperature Tt. It serves as a heat retention control means for performing heating control using a reference temperature Tc (for example, 70 ° C.) as a threshold value.

  For example, when the value Td detected by the pan temperature sensor 15 falls below the reference temperature Tc due to the temperature drop after the rice cooking process is finished, the measurement timer 30 starts measuring the elapsed time (time measuring means). Further, when the detected value Td reaches the temperature adjustment temperature Tk by further lowering the temperature, the induction heating coil 13, the body heater 14 and the lid heater 18 are controlled so as to maintain the temperature adjustment temperature Tk (first heating control means). ). While performing the temperature control, when the temperature rise time tm measured by the measurement timer 30 reaches the set temperature rise start time th, the induction heating coil 13 and the body heater 14 are controlled so as to rise to the heating target temperature Tt ( Second heating control means). In the first heating control (temperature adjustment step), the induction heating coil 13 and the body heater 14 are turned on for 1 second in 15 seconds, and are turned on / off using the temperature adjustment temperature Tk as a threshold value. In the second heating control (temperature raising step), duty control is performed so that the induction heating coil 13 and the body heater 14 are turned on for 3 seconds out of 15 seconds.

  Here, the difference between the conventional heat insulation process and the heat insulation process of this embodiment is demonstrated with reference to FIG. 3 (A) and (B).

  As shown in FIG. 3 (A), in the conventional heat retention process, the first temperature rise start time th1 after the rice cooking process is finished and the process proceeds to the heat retention process, and the second temperature rise is performed next. The temperature start time th2 is set. Moreover, the descending gradient of the temperature of the rice that naturally cools in an unheated state varies depending on the heat retention capacity, and a large amount indicated by a solid line is more gradual than a small amount indicated by a broken line. Therefore, the time tk1, tk2 maintained at the temperature adjustment temperature Tk is shorter in the large amount of temperature adjustment time tk1 than in the small amount of temperature adjustment time tk2. Therefore, the average temperature of cooked rice is higher in a larger amount than in a smaller amount.

  As shown in FIG. 3B, in the heat retention process of the present embodiment, the reference temperature Tc is set, and when the measurement time tm after the temperature falls below the reference temperature Tc due to the temperature drop, the temperature rise ( (Second heating control) is performed. Therefore, the temperature adjustment times tk1 and tk2 by the first heating control can be made substantially constant regardless of the heat retention capacity.

  The reference temperature Tc and the temperature rise start time th are set in consideration of yellowing caused by overheating and bacterial growth caused by underheating. The reference temperature Tc is set to a critical temperature that greatly affects the propagation of bacteria. When the temperature of the cooked rice is lower than the reference temperature Tc, the occurrence of yellowing can be suppressed, but the possibility that the bacteria will grow increases. On the other hand, when the temperature of the cooked rice is higher than the reference temperature Tc, the possibility of yellowing increases, but it is possible to suppress the growth of bacteria. The temperature increase start time th is a time that does not exceed the critical time (7 hours) during which the growth of the bacteria becomes significant (for example, 4 to 6 hours is preferable, and 5 hours in this embodiment).

(Correction of temperature rise time th)
The microcomputer 28 also serves as correction means for correcting the temperature increase time th for executing the temperature increase next time. When the lid 16 is opened, bacteria in the air may enter the inner pot 10. Moreover, when the lid body 16 is opened and the cooked rice in the inner pot 10 is taken out by the cooking utensil (chunky rice), the bacteria attached to the cooking utensil adhere to the cooked rice in the inner pot 10. Therefore, as shown in FIGS. 4A and 4B, when the open state of the lid body 16 is detected by the lid opening / closing sensor 25, the temperature rise time th is corrected so as to suppress the growth of bacteria. The correction target is only the first temperature increase control to be executed next, and the second temperature increase control to be executed thereafter is not corrected.

  Specifically, when the microcomputer 28 detects the opening of the lid body 16 via the lid opening / closing sensor 25, the microcomputer 28 measures the opening time tc by the measurement timer 30. When the cumulative opening time tt exceeds the set determination time tj (for example, 5 minutes), the first correction time tr1 (for example, 10 minutes) for which the temperature increase start time th is set is shortened. The accumulated time tt is reset when the temperature rise is executed.

  Further, the microcomputer 28 as the correcting means detects the inner pan temperature T0 by the pan temperature sensor 15 when the opening of the lid body 16 is detected, and detects the blockage of the lid body 16 by the pan temperature sensor 15. T1 is detected. When the temperature drop (T0-T1) with the lid 16 opened is larger than the first determination temperature Tj1 (for example, 5 ° C.), the second correction time tr2 (for example, the temperature increase start time th is set) 10 minutes) Set to shorten.

  However, the correction time tr when the lid 16 is opened and closed once is only one of the first correction time tr1 due to the cumulative time tt and the second correction time tr2 due to the decrease temperature (T0-T1) which is corrected a lot. Apply. That is, the correction time tr does not add both the first and second correction times tr1 and tr2. For example, when the accumulated time tt exceeds twice the determination time tj, the first correction time tr1 is set to 20 minutes. Further, when the decrease temperature (T0-T1) is equal to or higher than the first determination temperature Tj1 and less than twice, the second correction time tr2 is set to 10 minutes. In this case, the correction time tr is set to 20 minutes, and the temperature rise start time th is shortened by 20 minutes.

  Moreover, even if the microcomputer 28 detects the opening of the lid body 16, if the inner pot temperatures T0 and T1 being opened (particularly the inner pot temperature T1 when closed) are higher than the set second determination temperature Tj2, the microcomputer 28 increases. The temperature start time th is not shortened (corrected). The second determination temperature Tj2 is equal to or higher than the reference temperature Tc and lower than the heating target temperature Tt, and is set to be the same (70 ° C.) as the reference temperature Tc in this embodiment. The state in which the inner pot temperatures T0 and T1 are higher than the second determination temperature Tj2 is a temperature rising state, and in this state, the lid body 16 is opened and immediately kills even if bacteria enter.

  For example, during temperature rise (inner pan temperature is rising), the inner pan temperature T0 when the lid body 16 is opened is lower than the second determination temperature Tj2, and the inner pan temperature T1 when the lid body 16 is closed is The second determination temperature Tj2 may be exceeded. In this case, the inside of the inner pot 10 is in a state where the temperature is further increased after the lid body 16 is closed, and the bacteria can be killed in the temperature rising temperature atmosphere. After the temperature rise (inner pan temperature is descending), the inner pan temperature T0 when the lid body 16 is opened is higher than the second determination temperature Tj2, and the inner pan temperature T1 when the lid body 16 is closed is the second. It may be lower than the determination temperature Tj2. In this case, the temperature in the inner pot 10 is further lowered after the lid 16 is closed, and there is a possibility that the propagation of bacteria may be promoted. Therefore, only the time tc below the reference temperature Tc is added to the accumulated time tt. Then, the first correction time tr1 is set, and the second correction time tr2 is set based on the decrease temperature T0-T1.

(Temperature drop control after temperature rise)
The microcomputer 28 also serves as a temperature lowering control means for lowering the temperature at a gentler descending gradient than the natural temperature lowering after the temperature is raised to the heating target temperature Tt. Specifically, after the temperature rise, the first temperature drop control for controlling the temperature zone between the target heating temperature Tt and the reference temperature Tc and the second temperature zone for controlling the temperature zone between the reference temperature Tc and the temperature control temperature Tk. Perform temperature drop control. The energization rate of the first temperature decrease control is set to be higher than the energization rate of the second temperature decrease control and to have a gentler temperature decrease gradient than the second temperature decrease control. For example, the duty control is performed so that the induction heating coil 13 and the body heater 14 are turned on for 1 second in 30 seconds in the first temperature decrease control and for 1 second in 60 seconds in the second temperature decrease control. Thereby, the time of the temperature range above the reference temperature Tc is lengthened.

  Next, the heat insulation process by the microcomputer 28 will be specifically described.

  The heat retaining process is started after the rice cooking process is completed or by a switch operation of the operation panel unit 22 and is stopped by being stopped by a switch operation of the operation panel unit 22. In the heat retention process, the heating process illustrated in FIG. 5 and the temperature increase start time correction process illustrated in FIGS. 6A and 6B are repeatedly performed in parallel. Further, the temperature sensors 15 and 21 detect the temperatures Td and Tu, for example, every 25 ms.

(Heat treatment)
As shown in FIG. 5, in the heat treatment, the microcomputer 28 executes a first temperature decrease control process for decreasing the temperature with a gentle downward gradient in step S <b> 1. This 1st temperature fall control process is performed until detection value Td of temperature sensor 15 for pans becomes less than standard temperature Tc at Step S2.

  When the detected value Td falls below the reference temperature Tc, the first temperature fall control process is stopped, and the measurement timer 30 for measuring the temperature rise start time th is reset and started in step S3. Thereafter, in step S4, a second temperature lowering control step is performed in which the temperature is lowered at a lower gradient than the first temperature lowering control. This second temperature decrease control process is executed until the detected value Td reaches the temperature adjustment temperature Tk in step S5.

  When the detected value Td reaches the temperature control temperature Tk, the second temperature decrease control process is stopped, and the first heating control process for maintaining the temperature control temperature Tk is executed in step S6. This first heating control step is executed until the correction time tr set in the correction process in step S7 is read and the time (th-tr) obtained by subtracting the correction time tr from the temperature rise start time th in step S8 elapses. The

  After the detected value Td falls below the reference temperature Tc, when the corrected heating start time th-tr has elapsed, the first heating control process is stopped. In step S9, the measurement timer 30 is stopped, and in step S10, the correction time tr set in the correction process and the measured accumulated time tt are reset.

  Then, the 2nd heating control process which raises temperature of cooked rice via the inner pot 10 is performed at Step S11. This second heating control step is executed until the detected value Td reaches the heating target temperature Tt. When the detected value d reaches the heating target temperature Tt, the second heating control process is stopped, and the process returns to step S1.

  Thus, in the heat retention (heating) process of the present embodiment, the temperature is increased when the measurement time tm after the detection value Td of the pan temperature sensor 15 falls below the reference temperature Tc reaches the temperature increase start time th. Therefore, the temperature adjustment time maintained at the temperature adjustment temperature Tk can be made substantially constant regardless of the heat retention capacity. Therefore, since the excessive heating accompanying temperature control time becoming short can be suppressed, the water | moisture content release from cooked rice can be suppressed and deliciousness can be prevented from being impaired.

  Moreover, in this embodiment, since the temperature is lowered with a gentle descending gradient after the end of cooking rice or after the end of temperature raising, it is possible to ensure a long time in a temperature zone where bacteria can be sterilized. Therefore, the growth of bacteria can be reliably suppressed.

(Correction process)
As shown in FIG. 6A, in the temperature increase start time th correction process, the microcomputer 28 waits until it detects that the lid body 16 is opened via the lid opening / closing sensor 25 in step S20. When the opening of the lid 16 is detected, the inner pan temperature T0 is read in step S21, and it is determined whether or not the inner pan temperature T0 is lower than the second determination temperature Tj2 (reference temperature Tc) in step S22. If T0 <Tj2, the process proceeds to step S23, and if T0 <Tj2, the process proceeds to step S26.

  In step S23, it is determined whether or not the lid body 16 is closed. And when the cover body 16 is obstruct | occluded, it returns to step S20. If the lid 16 is not closed, the inner pan temperature T is read in step S24, and it is determined in step S25 whether the inner pan temperature T is lower than the second determination temperature Tj2. If T <Tj2, the process returns to step S23, and if T <Tj2, the process proceeds to step S26. That is, when the inner pot temperature T0 is equal to or higher than the second determination temperature Tj2, when the inner pot temperature T falls below the second determination temperature Tj2 while the lid 16 is opened, the process proceeds to step S26, and the inner pot temperature T is determined to be the second determination. When the lid 16 is closed without falling below the temperature Tj2, the process returns to step S20.

  In step S26, the measurement timer 30 for measuring the opening time tc of the lid body 16 is reset and started, and then waits until the closure of the lid body 16 is detected in step S27. And if the cover body 16 is obstruct | occluded, the measurement timer 30 of the open time tc will be stopped by step S28. Thereafter, in step S29, the inner pot temperature T1 is read, and in step S30, it is determined whether or not the inner pot temperature T1 is lower than the second determination temperature Tj2. And when the inner pot temperature T1 at the time of obstruction | occlusion is more than 2nd determination temperature Tj2, ie, when it is heating up, it returns to step S20. Further, when the inner pot temperature T1 is lower than the second determination temperature Tj2, the process proceeds to steps S31 and S36 shown in FIG. 6B.

  As shown in FIG. 6B, when the inner pan temperature T1 at the time of closing is less than the second determination temperature Tj2, the first correction setting in steps S31 to S35 and the second correction setting in steps S36 to S38 are processed in parallel. To do.

  In the first correction setting, after adding the open time tc measured to the cumulative time tt in step S31, it is determined whether or not the cumulative time tt exceeds the determination time tj in step S32. If tt> tj, the first correction time tr1 is set in step S33, and then the determination time tj is subtracted from the accumulation time tt in step S34 to adjust the accumulation time tt. If not tt> tj, the first correction time tr1 is set to 0 minutes in step S35.

  In the second correction setting, whether or not the lowering temperature obtained by subtracting the inner pan temperature T1 when the lid body 16 is closed from the inner pan temperature T0 when the lid body 16 is opened is larger than the first determination temperature Tj1 in step S36. Judging. If (T0−T1)> Tj1, the second correction time tr2 is set in step S37. If (T0−T1)> Tj1 is not satisfied, the second correction time tr2 is set to 0 minute in step S38.

  When the first and second correction settings are completed, it is determined in step S39 whether or not the first correction time tr1 is equal to or longer than the second correction time tr2. If tr1 ≧ tr2, the first correction time tr1 is added to the correction time tr in step S40, and the process returns to step S20. If tr1 ≧ tr2, the second correction time tr2 is added to the correction time tr in step S41, and the process returns to step S20.

  As described above, when the opening of the lid body 16 is detected, the correction time tr is set based on the accumulated time tt and the temperature drop (T0-T1). And it correct | amends so that the temperature rising start time th in heat processing may be shortened. Therefore, the proliferation of the invading bacteria can be suppressed and the sterilization of the bacteria can be promoted. Moreover, when the temperature T1 at the time of closing is higher than the second determination temperature Tj2, it is determined that the temperature is being raised, and the temperature rise start time th is not shortened. Can be reliably prevented from being damaged.

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

  For example, in the above embodiment, when the temperature is raised from the temperature adjustment temperature Tk to the heating target temperature Tt, the duty control is performed at a constant energization rate. However, the first temperature range from the temperature adjustment temperature Tk to the reference temperature Tc is used. The energization rate in the second temperature range from the reference temperature Tc to the heating target temperature Tt may be set differently. Specifically, in the first temperature increase control step in the first temperature zone, duty control is performed so that the induction heating coil 13 and the body heater 14 are turned on for 3 seconds in 15 seconds. In the second temperature increase control step in the second temperature zone, the duty control is performed so that the induction heating coil 13 and the body heater 14 are turned on for 2 seconds out of 15 seconds. In this way, the time zone in which the bacteria can be sterilized is ensured for a long time and the growth of the bacteria is surely suppressed.

  Moreover, in the said embodiment, when a heat retention process is performed by switch operation of the operation panel part 22, according to the inner pot temperature Td at that time, either a 1st temperature fall control process, a 2nd temperature fall control process, and a 1st heating control process However, the start time for executing the temperature rise (second heating control step) may be changed based on the inner pan temperature Td during switch operation. Specifically, when the inner pot temperature Td is lower than the temperature control temperature Tk, the temperature is immediately increased. Further, when the inner pot temperature Td is higher than the temperature control temperature Tk and lower than the reference temperature Tc, the temperature is increased after a half time (1 / 2th) of the temperature increase start time th has elapsed. Alternatively, the temperature rise time executed immediately before the heat retention process is completed is stored, and the temperature rise is executed after the temperature rise start time th has elapsed from that time (immediately if it has already elapsed). . Furthermore, when the inner pot temperature Td is higher than the reference temperature Tc, the temperature is increased after the temperature increase start time th has elapsed.

  Furthermore, when a power failure occurs during the heat insulation process and the power is restored, the start time for executing the temperature increase may be changed based on the power failure time. Specifically, when the power failure time is short (for example, about 3 minutes), the temperature increase start time th is not shortened, and when the power failure time is long (for example, 10 minutes or longer), the temperature increase start time th is shortened.

  And in the said embodiment, although the non-pressure type rice cooker which cannot raise the internal pressure of the inner pot 10 to pressure higher than atmospheric pressure was mentioned as an example, the pressure type which can raise pressure to pressure higher than atmospheric pressure was demonstrated. It can be applied to other rice cookers, and similar actions and effects can be obtained. Moreover, not only a rice cooker but 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 same action and effect can be obtained even if the object to be kept warm is not only cooked rice but also cooked dishes such as side dishes. Of course, the same action and effect can be obtained as long as the food is not limited to the cooked food and needs to be kept at a predetermined temperature.

10 ... inner pot 11 ... rice cooker body (equipment body)
12 ... Accommodating part 13 ... Induction heating coil (heating means)
14 ... Body heater (heating means)
15 ... Pot temperature sensor (temperature detection means)
16 ... Lid 17 ... Heat dissipation plate 18 ... Lid heater (heating means)
DESCRIPTION OF SYMBOLS 19 ... Inner lid 20 ... Exhaust passage 21 ... Cover temperature sensor (temperature detection means)
DESCRIPTION OF SYMBOLS 22 ... Operation panel part 23 ... Switch 24 ... Liquid crystal display board 25 ... Cover opening / closing sensor 26 ... Holder 27 ... Control board 28 ... Microcomputer (each control means)
29 ... ROM
30 ... Measurement timer Ts1 ... First set temperature Ts2 ... Second set temperature Td ... Lower detection value Tu ... Upper detection value Tk ... Temperature control temperature Tt ... Heating target temperature Tc ... Reference temperature Tj1 ... First determination temperature Tj2 ... Second Judgment temperature tm ... Measurement time th ... Temperature increase start time tk1, tk2 ... Temperature adjustment time tc ... Cover opening time tt ... Opening accumulated time tj ... Determination time tr ... Correction time tr1 ... First correction time tr2 ... Second correction time

Claims (7)

A heat retaining device that heats the food in the device body by a heating means based on the detection value of the temperature detecting means, and keeps the food in a heat retaining temperature zone corresponding to the food
First heating control means for controlling the heating means so that the detected value of the temperature detecting means maintains a temperature control temperature that is the lower limit of the heat retaining temperature zone;
Second heating control means for controlling the heating means so that the detection value of the temperature detection means rises to the heating target temperature at the upper limit of the heat retaining temperature zone;
Time measuring means for measuring a time during which the detected value of the temperature detecting means is lower than a reference temperature higher than the temperature control temperature and lower than the heating target temperature;
When the temperature is adjusted to the temperature control temperature by the first heating control means, and when the measurement time by the time measuring means reaches the temperature rise start time, the heat retention control means for raising the temperature to the heating target temperature by the second heating control means,
A thermal insulation device comprising: A lid that closes the device main body so as to be openable; and a lid state detecting means that detects an open state of the lid,
2. The heat retention device according to claim 1, wherein the heat retention control unit corrects the temperature rise start time when the lid state detection unit detects the opening of the lid body.   The heat retention control means according to claim 2, wherein the heat retention control means measures the opening time of the lid, and shortens the temperature rise start time when the cumulative opening time exceeds a determination time. machine.   The said heat retention control means resets the said accumulation time, if a temperature rise is performed by the said 2nd heating control means, The heat retention apparatus of Claim 3 characterized by the above-mentioned.   The temperature keeping control means detects a temperature drop during opening of the lid by the temperature detection means, and when the temperature drop is larger than a first determination temperature, the temperature rise start time is shortened. The heat insulation apparatus according to any one of claims 2 to 4.   The temperature keeping control means detects the temperature when the lid is opened by the temperature detecting means, and when the detected value is higher than the second determination temperature equal to or higher than the reference temperature, the temperature rising start time is not shortened. The heat retaining device according to any one of claims 2 to 5, wherein the heat retaining device is characterized in that:   7. The temperature control device according to claim 1, further comprising a temperature-decreasing control unit that lowers the temperature at a gentler downward gradient after the temperature is raised by the second heating control unit than when the heating unit is stopped. Thermal insulation equipment as described.

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