JPH1023966A - Method for detecting rate of change of external air temperature in which temperature control object is placed, method for retaining warmth of boiled rice in rice cooker using the same and rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate a temperature detecting means for detecting an external air temperature by detecting the temperature change cycle of a temperature control object to cyclically change by intermittently applying heating or cooling operation while affected by the external air temperature, and detecting the rate of change of the external air temperature while using the change rate of this temperature change cycle. SOLUTION: A lid body 4 is attached to an outer vessel 3 for housing a rice cooking vessel 2 so as to be opened/closed, a gas burner 5 is provided under the bottom part of the rice cooking vessel 2 and as the temperature control object, an electric heater 7 is provided so as to surround a flame opening part 6 of this gas burner 5. Then, a controller 10 controls the operation of the gas burner 5 according to a set rice cooking pattern, the heating or cooling operation is intermittently applied while affected by the external air temperature, the temperature change cycle of the electric heater 7 to cyclically change is detected and while using the change rate of this temperature change cycle, the change rate of the external air temperature is detected. Thus, the temperature detecting means for detecting the change of the external air temperature can be unnecessitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a rate of change in the outside air temperature at which a temperature-controlled object is placed, a method for keeping rice cooked in a rice cooker using this method, and a rice cooker. More specifically, the change rate of the outside air temperature is detected by using a change in the temperature cycle of the temperature control target that is maintained at a predetermined target temperature while being affected by the outside air temperature.

[0002]

2. Description of the Related Art For example, in a rice cooker, cooked rice is kept at a constant temperature in a rice cooker after a rice cooking operation is completed, so that hot rice can be provided for a long time. Many. The rice cooker is provided with a rice cooker that stores and cooks cooked rice, and is configured to perform a rice cooking operation of cooking and heating the rice cooker and a warming operation of keeping the rice cooker heated and maintained at a predetermined temperature. ing.

As a rice heating means for performing a rice cooking operation, a gas heater such as a gas burner, an electric heater, an induction heating device and the like are employed. On the other hand, an electric heater or the like is often used as a heat retaining heating means for performing a heat retaining operation, and weak heating is often performed. During the warming operation, the temperature of the rice cooker is detected by a temperature detecting means such as a thermistor, and the electric heater or the like is turned on so as to maintain the temperature of the rice cooker at about 70 ° C.
It is configured to perform OFF control.

[0004]

As described above, the above-mentioned heat-retaining operation is performed by comparing a temperature detected by temperature detecting means provided at a predetermined portion of the rice cooker with a preset target temperature. , Electric heater, etc. ON-O
The temperature of the rice cooker is kept almost constant by FF control. Therefore, the temperature of the rice cooker periodically changes within an allowable temperature range around the target temperature.

[0005] When the temperature of the outside air drops sharply, the temperature of the rice cooker is also easily affected by the outside air temperature and tends to drop sharply. Particularly, in the case of a rice cooker in which the heat retaining heat passage is configured to communicate with the outside air, the influence is large. However, since the inside of the rice cooker is full of saturated water vapor, when the temperature of the rice cooker suddenly drops, the saturated vapor pressure also decreases in accordance with the temperature, and excess steam condenses and the inner surface of the rice cooker becomes Condensation forms on the surface. Furthermore, when the amount of dew increases, it flows along the inner surface of the container and stays at the bottom of the rice cooker. For this reason, the rice cooked at the bottom of the rice cooker contains a large amount of moisture, causing a problem such that the cooked rice becomes sticky and taste deteriorates.

[0006] Further, odors and the like easily occur due to dew condensation, and the taste of cooked rice is further reduced. In order to solve the above problem, it is conceivable to immediately detect a change in the outside air temperature, raise the heat retaining temperature so as to prevent dew condensation, or perform a dew condensation removing operation for removing the formed dew condensation. However, in order to accurately detect the outside air temperature, a temperature sensor for detecting the outside air temperature must be separately provided on the outer surface of the rice cooker or the like, which greatly increases the manufacturing cost. In addition, it is necessary to detect the change in the outside air temperature with high accuracy without being affected by the thermal insulation heating means for performing the thermal insulation operation, which causes a problem that the structure becomes complicated.

The present invention has been conceived in view of the above-mentioned circumstances, and solves the above-mentioned conventional problems. Therefore, it is possible to easily detect a change rate of the outside air temperature at which a temperature control target is placed. It is an object of the present invention to provide a method that can be used, a method for keeping rice cooked in a rice cooker using the method, and a rice cooker.

[0008]

Means for Solving the Problems To solve the above problems, the present invention takes the following technical means. The invention described in claim 1 of the present application is a method for detecting a rate of change of an outside air temperature at which a temperature control target configured to be maintained at a predetermined target temperature is placed. Detecting the temperature change cycle of the temperature control object that periodically changes due to intermittent heating or cooling operations, and detecting the rate of change of the outside air temperature using the rate of change of the temperature change cycle. It is characterized by.

As a temperature control object to which a heating operation is applied,
A rice cooker for keeping cooked rice at a certain temperature, a water heater for storing hot water at a certain temperature and supplying hot water, and the like can be given. on the other hand,
Refrigerators, freezers, ice making devices, and the like can be given as temperature control objects to which a cooling operation is applied. A heating operation or a cooling operation is applied to the temperature control target as described above under the influence of the outside air temperature, and the target is maintained at a predetermined target temperature. Normally, the heating operation or the cooling operation is performed intermittently, so that the temperature of the temperature control object periodically changes within an allowable temperature range.

The cycle of the temperature change is greatly affected by a change in the outside air temperature at which the temperature control object is placed. That is, when the outside air temperature changes rapidly, the flow of heat between the outside air and the outside air increases, the temperature change of the temperature control target itself increases, the interval between the heating operation and the cooling operation changes, and the temperature cycle also changes. I do. The invention of the present application is to detect the temperature change cycle of the above-mentioned temperature control object, and to detect the change rate of the outside air temperature using the change rate of the temperature change cycle.

By using the above method, a temperature detecting means for detecting a change in the outside air temperature becomes unnecessary. Therefore, a control operation corresponding to a change in the outside air temperature can be achieved without increasing the manufacturing cost. In addition, since the outside air temperature can be detected using the temperature control target itself that is subjected to the heating operation or the cooling operation while being affected by the outside air temperature, it is not necessary to consider the influence of the heating unit, the cooling unit, and the like. Can be quickly and accurately detected.

[0012] The invention described in claim 2 of the present application is provided with a rice cooker for storing and heating and cooking rice, a rice cooking operation for cooking and heating the rice cooker, and keeping the rice cooker at a predetermined temperature by heating and heating. A method of maintaining a temperature in a rice cooker that performs a heat retaining operation that detects an outside air temperature and a temperature change cycle of a rice cooker that changes due to the heat retaining operation, and when a rate of decrease in the temperature cycle becomes a predetermined value or more. In addition, it is characterized in that it is determined that dew condensation has occurred in the rice cooker due to an increase in the decrease rate of the outside air temperature, and a dew condensation operation for removing the dew formed in the rice cooker is performed.

During the warming operation, the temperature of the rice cooker changes periodically depending on the outside air temperature and the ON / OFF operation of the heater. When the outside air temperature drops rapidly, the speed of the temperature drop of the rice cooker increases, and the ON-OF of the heater is turned off.
The frequency of the F operation increases, and the temperature cycle decreases.
The present invention focuses on the fact that when the outside air temperature changes abruptly, the temperature change cycle of the rice cooker, which is kept substantially constant by the heat retaining means, changes. This is intended to detect the occurrence of dew and to detect the occurrence of dew, thereby performing a dew condensation operation.

For example, the temperature cycle can be obtained by measuring the time during which the heater is turned on and off, or by counting the number of times the heater is repeatedly turned on and off per predetermined time. Then, the rate of change of the temperature cycle is obtained by comparing the temperature cycles obtained at different times, and the dew condensation removing operation can be controlled based on this rate.

When the rate of decrease in the temperature cycle increases, it is when the outside air temperature sharply decreases, and the temperature of the rice cooker also sharply decreases. For this reason, it can be determined that the saturated vapor pressure in the rice cooker also decreases in accordance with the temperature, and that excess steam condenses and dew forms on the inner surface of the rice cooker. The dew condensation removing operation only needs to be an operation capable of removing dew condensation generated in the rice cooker. For example, it is conceivable to heat the rice cooker for a short period of time using a rice cooker or the like to evaporate dew condensation on the inner surface of the rice cooker. It is also conceivable that the saturated steam in the rice cooker is sucked to lower the wetness of the steam in the rice cooker.

The present invention can be applied, for example, to various rice cookers configured to keep cooked rice after cooking rice. Further, the present invention is not limited to rice cookers for general household use, but also includes rice cookers for business use used in restaurants, catering factories and the like. The rice heating means for performing the rice cooking operation and the heat retaining and heating means for performing the heat retaining operation are not particularly limited, and those using gas combustion, such as a gas burner, or electricity, such as an electric heater or an induction heating device, can be employed. . In addition, the rice cooking heating means and the heat retaining heating means can be used as a single device. In addition, when performing the dew condensation operation by heating, in order to prevent deterioration of the cooked rice due to heat, the cooked rice in the rice cooker is rapidly heated,
It is preferable to evaporate the condensation in a short time.

The heat retention temperature is often set to about 70 ° C. because it is necessary to take into account the deterioration of cooked rice due to heat.
According to the third aspect of the present invention, a rice cooker for storing rice, a rice cooker for heating the rice cooker, and a heater being ON-OFF controlled to intermittently heat the rice cooker to a predetermined temperature. Heat retaining heating means for maintaining the temperature,
A rice cooker including a temperature detection unit that detects the temperature of the rice cooker and a control unit that controls the operation of the heat retention and heating unit, and detects the number of ON-OFF repetitive operations of the heater per predetermined time, While providing the number-of-times-of-operation detection comparing means for comparing with the number of times of repetition detected earlier, when the number-of-times-of-operation detection / comparison means detects that the rate of increase in the number of times of repetition of the heater has exceeded a predetermined value, In addition, it is characterized in that it is determined that dew condensation has occurred in the rice cooker due to an increase in the rate of decrease in the outside air temperature, and control is performed to perform a dew condensation operation for removing dew in the rice cooker.

The invention described in the present invention is characterized in that the outside air temperature and
Focusing on the fact that there is a certain relationship between the number of times the heater is turned on and off repeatedly, the configuration is such that the dew condensation operation is performed by indirectly detecting the rate of decrease in the outside air temperature.
When the outside air temperature drops sharply, the temperature of the rice cooker also drops sharply, and the ON-OFF operation cycle of the heater also decreases. Therefore, by detecting the number of times the heater is repeatedly operated per predetermined time and calculating the rate of increase in the number of times of operation, the rate of decrease in the outside air temperature can be indirectly detected, and the occurrence of condensation can be detected.

In order to detect the number of times of operation, a counter interlocked with the ON operation or OFF operation of the heater can be employed. And, in addition to the counter, a timer for measuring a predetermined detection time, a storage means for storing the previously detected number of times of operation, a calculating means for obtaining a ratio with the previously detected number of times of operation, and the like are provided. The number-of-times detection comparing means is configured.

The rate of increase in the number of times of operation is closely related to the rate of decrease in the outside air temperature, and the dew condensation operation can be controlled based on the rate of increase in the number of times of repeated operation.
Then, the generated dew is quickly removed to prevent stickiness of the cooked rice. Also, by removing condensation, effectively prevent the growth of microorganisms, without reducing the taste,
The rice can be kept warm for a long time.

The type of rice cooker is not particularly limited, and can be applied to a gas rice cooker, an electric rice cooker of a heater heating type, a rice cooker of an electromagnetic induction heating type, and the like. As the control means for controlling the rice cooking heating means and the heat keeping heating means, a control means incorporating a microcomputer can be adopted. Further, the dew condensation removing operation is not particularly limited. For example, as in the invention described in claim 4, the dew condensation removing operation can be performed by temporarily heating the rice cooker using rice cooker heating means. Further, a heating means for the dew condensation removing operation may be separately provided to temporarily heat the rice cooker.

Further, the rice cooking heating means and the heat retaining heating means are not limited to one type, but may be constituted by combining types utilizing gas, electricity or the like. While a gas burner is used as the rice cooking heating means, an electric heater can be used as the heat retaining heating means.

[0023]

According to the present invention, the rate of change of the outside air temperature is detected by using the change of the temperature change cycle of the temperature control object, so that the temperature detecting means for detecting the change of the outside air temperature becomes unnecessary. Therefore, a control operation corresponding to a change in the outside air temperature can be achieved without increasing the manufacturing cost.

In addition, since the temperature of the outside air can be detected using the temperature control object itself that is subjected to the heating operation or the cooling operation while being affected by the outside air temperature, it is not necessary to consider the influence of the heating means, the cooling means, and the like. In addition, the outside air temperature can be detected quickly and accurately. In particular, in a warming operation of the rice cooker, by detecting a rapid decrease in the outside air temperature, the generated dew can be immediately evaporated and removed. For this reason, the dew condensation does not stay at the bottom of the rice cooker, and the cooked rice does not stick.

Further, since there is no dew condensation, the generation of unpleasant odor can be prevented for a long time. For this reason, it becomes possible to keep rice cooked for a long time without deteriorating the taste.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an outline of a rice cooker according to the present embodiment. This embodiment employs a gas burner as a rice cooking heating means for performing a rice cooking operation,
The present invention is applied to a rice cooker employing an electric heater as a heat-retaining heating means for performing a heat-retaining operation.

As shown in FIG. 1, a rice cooker 1 has a rice cooker 2 for storing and cooking rice and the like, an outer container 3 for storing the rice cooker 2, and an openable and closable attachment to the outer container 3. A lid 4, a gas burner 5 provided below the bottom of the rice cooker 2, an electric heater 7 provided to surround the flame opening 6 of the gas burner 5, and a rice cooker 2.
And a temperature sensor 8 provided so as to be in contact with the bottom surface of the electronic device. In addition, an ignition device 9 is arranged near the flame opening 6.

The operation of the gas burner 5 and the electric heater 7 is controlled by a control device 10 having a microcomputer. The operation of the gas burner 5 is controlled in accordance with a set rice cooking pattern, so that ignition timing, fire extinguishing timing,
Cook rice while controlling the heat power. After the rice cooking operation, the electric heater 7 is controlled to be ON-OFF based on the temperature detected by the temperature sensor 8 to keep the inside of the rice cooking container at a substantially constant temperature.

In the rice cooker shown in FIG. 1, a gap 11 is provided between the rice cooker 2 and the outer container 3 surrounding the rice cooker 2 so that the rice cooker 2 is heated from the surroundings by the exhaust gas passing through the gap 11. This is a so-called tsutsumi-cooking rice cooker. The gap 11 is also used as a heat discharge passage for heat retention by the heater 7, and communicates with a heat discharge space 12 a through a communication port 12 provided in an upper portion of the outer container 3. , And communicates with the outside through an exhaust port (not shown) provided on a side surface of the rice cooker. For this reason, the rice cooker 2 is easily affected by the outside air, and if the outside air temperature changes suddenly, the temperature of the peripheral wall portion of the rice cooker 2 decreases, and dew condensation easily occurs on the inner surface on the side where the cooked rice is stored.

In the present embodiment, the method of detecting the rate of change of the outside air temperature according to the present invention is applied to the above-mentioned conventional rice cooker. FIG. 2 is a flowchart showing a control flow according to the present invention. First, after the gas burner 5 is extinguished to end the rice cooking operation (S101), K = 1 and M = 1 are given as initial values of a memory provided in the control device 10 (S102). This K is provided to count the number of times the heater is operated. On the other hand, M is provided to store the number of times of operation detected earlier.

After the rice is cooked, when the temperature of the rice cooker 2 drops to 68 ° C. or lower (S103), the heater 7 is turned on (S104). The count timer is started in conjunction with the heater ON (S105). When the temperature of the rice cooker 2 rises to 72 ° C. or more, the heater 7
FF is performed (S107). In the present embodiment, the K of the memory is linked to the OFF operation of the heater 7.
Is replaced with K + 1 (S108). The initial value of K is 1
Therefore, in this state, K = 2.

Until the count timer expires, the ON / OFF operation of the heater 7 is repeated.
The value of K increases. In the present embodiment, the value of the count timer is set to 30 minutes. When the count timer expires (S109), the control device 1
K / M is obtained by the operation number detection comparison means within 0. Since the above-mentioned M has an initial value of 1, K / M is 2
Be larger.

In the present embodiment, the condition for the occurrence of dew condensation when the outside air temperature changes abruptly is determined based on the temperature cycle of the rice cooker according to the outside air temperature, and the rate of increase in the number of operations K / M ≧
It is set to 1.2, and when the value of K / M is 1.2 or more, control is performed so as to start the dew condensation removing operation according to the present invention. After the rice is cooked, the temperature of the rice cooker 2 is rapidly reduced from the rice cooking temperature by the time the heater 7 is operated for the first time, so that dew condensation may occur. In the present embodiment, 1 is given as an initial value of M so that after the heater 7 is operated for the first time after the rice cooking operation, the dew condensation operation is performed.

When the value of K / M is 1.2 or more,
The gas burner 5 is ignited to perform a dew condensation removing operation (S11).
1). In the present embodiment, the ignition timer is started simultaneously with the ignition of the gas burner 5 (S112), and about 10
The rice cooker 2 is heated for a second. After the heating is performed for 10 seconds and the above-mentioned ignition timer times out (S113), the gas burner 5 is extinguished to end the dew condensation removing operation (S11).
4).

In conjunction with the termination of the dew condensation operation, the number of heaters previously detected is entered in the memory M, and K is returned to the initial value 1 (S115). After the replacement of the memory is completed, the process returns to the normal warming mode, and when the temperature of the rice cooker 2 becomes 68 ° C. or less, the heater 7 is repeatedly operated, and the cout timer is started to reduce the number of times the heater 7 is operated. To detect.

In detecting the number of times of operation after the second time,
Since the number of times of operation of the heater previously detected in S115 is stored in the memory M, the value of K / M indicates the rate of change of the temperature cycle of the rice cooker. In addition, the above K /
When the value of M is equal to or less than 1.2, the values of the memory M and the memory K are exchanged without performing the dew condensation operation, and the determination is made after the subsequent detection of the number of heater operations. ing.

Therefore, the number of heater operations detected immediately before is stored in M, and control is performed by comparing this value with the detected value of the number of heater operations performed next. When the value of K / M is 1.2 or more, it means that the cycle of the temperature change of the rice cooker has been reduced by 20% or more, and the outside air temperature has rapidly dropped, and dew condensation has occurred in the rice cooker. It is thought that it is. In addition, the value of the above-mentioned number-of-times-of-operations increase rate K / M, which is a reference for control, is not limited to 1.2, and can be changed according to the capacity of the rice cooker, the warming temperature, the amount of cooked rice and the like.

By performing control based on the rate of decrease in the temperature cycle of the rice cooker, particularly based on the rate of increase in the number of times of operation of the heater 7, it is possible to eliminate the need for a separate highly accurate water drop generation detection sensor or the like. It is possible to detect the occurrence of dew condensation caused by a sharp drop in the outside air temperature, and control the dew condensation removal operation based on the detection. In addition, during the warming operation, dew condensation caused by a sudden change in the outside air temperature can be immediately evaporated and removed. For this reason, the dew condensation does not stay at the bottom of the rice cooker, and the cooked rice does not stick.

Further, since the above-mentioned dew condensation is eliminated, generation of an unusual odor can be prevented for a long time. Furthermore, since the rice cooker is temporarily heated, it is possible to keep rice cooked for a long time without deteriorating the taste. On the other hand, in the dew condensation step, the rice cooker is only temporarily heated by the heat enough to remove the dew, so that the cooked rice hardly deteriorates.

The present invention is not limited to the above embodiment. In the embodiment, the dew-condensing operation is performed immediately after the rice cooking. However, the dew-condensing operation can be controlled to be performed under normal conditions. Although the number of times of operation is counted in conjunction with the OFF operation of the heater 7, the number of times of operation may be counted in conjunction with the ON operation of the heater 7.

Further, the time for detecting the number of times of operation of the heater is not limited to the embodiment, but can be changed according to the operation cycle or the like. The dew-condensation removing operation is not limited to the operation of evaporating dew condensation by temporary strong heating as in the above-described embodiment. For example, the dew-removing operation is configured to prevent dew condensation by sucking saturated steam. You can also.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an outline of a configuration of a rice cooker according to the present invention.

FIG. 2 is a flowchart illustrating an example of control according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rice cooker 2 ... Rice cooker 5 ... Gas burner 7 ... Electric heater 10 ... Control means

Claims (4)

[Claims] 1. A method for detecting a rate of change of an outside air temperature at which a temperature control object configured to be maintained at a predetermined target temperature is placed, wherein a heating operation or a cooling operation is affected by the outside air temperature. Detecting a temperature change cycle of the temperature control object that periodically changes by being intermittently added, and detecting a change rate of the outside air temperature using the change rate of the temperature change cycle; A method of detecting the rate of change of temperature. 2. A rice cooker comprising a rice cooker for storing and cooking rice cooked therein, the rice cooker performing a rice cooking operation of cooking and heating the rice cooker, and a warming operation of keeping the rice cooker heated and maintained at a predetermined temperature. A method of keeping heat, wherein while detecting the outside air temperature and the temperature change cycle of the rice cooker that changes due to the heat keeping operation, when the rate of decrease of this temperature cycle becomes a predetermined value or more,
Judging that the rate of decrease in the outside air temperature has increased and dew has formed in the rice cooker, and performing a dew condensation removing operation for removing the dew formed in the rice cooker, wherein the method for keeping heat in the rice cooker is performed. . 3. A rice cooker for storing rice, a rice cooker for heating the rice cooker, and an ON-OF heater.
By performing F control, a heating and heating unit that intermittently heats the rice cooker to maintain a predetermined temperature, a temperature detection unit that detects the temperature of the rice cooker, and a control unit that controls the operation of the warming and heating unit. A rice cooker comprising: an operation frequency detecting / comparing means for detecting the number of times the heater is repeatedly turned on and off per predetermined time and comparing the number of times of operation with the previously detected number of times of operation. When it is detected by the comparing means that the rate of increase in the number of repetitive operations of the heater is equal to or greater than a predetermined value, it is determined that the rate of decrease in the outside air temperature has increased and condensation has occurred in the rice cooker, A rice cooker characterized by performing control to perform a dew condensation removing operation for removing dew in a rice cooker. 4. The rice cooker according to claim 3, wherein the dew condensation removing operation is performed by temporarily heating the rice cooker using the rice cooker.