JP3497951B2 - A method of detecting a change rate of an outside air temperature at which a temperature control target is placed, a method of keeping rice cooked in a rice cooker using the method, and a rice cooker - Google Patents

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 the rate of change of the outside air temperature on which a temperature controlled object is placed, a method for keeping cooked rice in a rice cooker using this method, and a rice cooker. Specifically, the rate of change of the outside air temperature is detected by utilizing the change in the temperature cycle of the temperature controlled object 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, there is a rice cooker constructed so that cooked cooked rice can be kept at a constant temperature in a cooked rice container after the rice cooking operation is completed and hot cooked rice can be provided for a long time. Many. The rice cooker includes a rice cooking container that accommodates and cooks cooked rice, and is configured to perform a rice cooking operation of heating the rice cooking container and a heat retaining operation of heating the rice cooking container to keep it at a predetermined temperature. ing.

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

[0004]

As described above, in the heat retaining operation, the detected temperature detected by the temperature detecting means provided at a predetermined portion of the rice cooking container is compared with the preset target temperature. Turn on the electric heater, etc.
FF control is performed to keep the temperature of the rice cooking container substantially constant. Therefore, the temperature of the rice cooking container changes periodically within the allowable temperature range around the target temperature.

When the temperature of the outside air suddenly drops, the temperature of the rice cooking container is also affected by the outside air temperature and is likely to drop sharply. This effect is particularly great in the case of a rice cooker configured so that the heat retention heat passage communicates with the outside air. However, because the steam inside the rice cooking container is filled with saturated water vapor, when the temperature of the rice cooking container drops sharply, the saturated vapor pressure also decreases in accordance with the temperature, and excess steam condenses and the inner surface of the rice cooking container is condensed. Condensation occurs on the. Further, when the amount of dew condensation increases, it flows along the inner surface of the container and stays at the bottom of the rice cooking container. For this reason, the cooked rice at the bottom of the rice cooking container contains a large amount of water and becomes sticky, resulting in a problem that the taste is deteriorated.

[0006] Further, dew condensation easily causes odor and the like, which further deteriorates the taste of cooked rice. In order to solve the above problem, it is conceivable to immediately detect a change in the outside air temperature, raise the heat retention temperature so that dew condensation does not occur, or perform a dew condensation removal operation to remove the generated dew condensation. However, in order to detect the outside air temperature with high accuracy, it is necessary to separately provide a temperature sensor for detecting the outside air temperature on the outer surface of the rice cooker or the like, which greatly increases the manufacturing cost. In addition, the structure must be configured to detect the change in the outside air temperature with high accuracy without being affected by the heat of the heat-retaining / heating means that performs the heat-retaining operation, which causes a problem that the structure becomes complicated.

The present invention has been devised under the circumstances described above, and it is possible to solve the conventional problems described above and to easily detect the rate of change of the outside air temperature on which the temperature controlled object is placed. It is an object of the present invention to provide a possible method, a method for keeping cooked rice in a rice cooker using this method, and a rice cooker.

[0008]

In order 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 the rate of change of the outside air temperature on which a temperature control target configured to be maintained at a predetermined target temperature is placed, while being affected by the outside air temperature. Detecting the temperature change cycle of the temperature controlled object that changes periodically due to intermittent heating or cooling operation, and detecting the change rate of the outside air temperature using the change rate of this temperature change cycle. Is characterized by.

As the temperature controlled object to which the heating operation is applied,
Examples include a rice cooking container that keeps cooked rice at a constant temperature, a water heater that stores hot water at a constant temperature and supplies the hot water. on the other hand,
A refrigerator, a freezer, an ice making device, or the like can be given as the temperature control target object to which the cooling operation is applied. The temperature control target as described above is configured to be heated or cooled while being affected by the outside air temperature, and to be held at a predetermined target temperature. Usually, the heating operation or the cooling operation is performed intermittently, so that the temperature of the temperature controlled object periodically changes within the allowable temperature range.

The change cycle of the temperature is greatly affected by the change of the outside air temperature on which the temperature controlled object is placed. That is, when the outside air temperature changes abruptly, the flow of heat between the outside air and the temperature of the temperature controlled object itself increases, the heating or cooling operation interval changes, and the temperature cycle also changes. To do. The present invention is to detect the temperature change cycle of the temperature control target and detect the change rate of the outside air temperature using the change rate of the temperature change cycle.

By using the above method, the temperature detecting means for detecting the change in the outside air temperature becomes unnecessary. Therefore, the control operation corresponding to the change in the outside air temperature can be achieved without increasing the manufacturing cost. Further, while being affected by the outside air temperature, the outside air temperature can be detected by utilizing the temperature controlled object itself which is heated or cooled, so that it is not necessary to consider the influence of the heating means, the cooling means, etc. Can be detected quickly and accurately.

The invention as set forth in claim 2 of the present application is provided with a rice cooking container for accommodating and cooking cooked rice, and a rice cooking operation for heating the rice cooking container and heating the rice cooking container to keep it at a predetermined temperature. When the temperature change cycle of the rice cooker that changes due to the outside air temperature and the heat retention operation is detected and the rate of decrease of this temperature cycle becomes equal to or greater than a predetermined value. In addition, it is characterized in that it is determined that dew condensation has occurred in the rice cooking container due to a large decrease rate of the outside air temperature, and a dew condensation removing operation is performed to remove the dew condensation generated in the rice cooking container.

The temperature of the rice cooking container during the heat retaining operation periodically changes depending on the outside air temperature and ON / OFF operation of the heater. When the outside air temperature drops sharply, the rate of temperature drop of the rice cooking container increases, and the ON-OF of the heater is turned on.
The frequency of F operation also 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 cooking container, which is kept substantially constant by the heat retaining means, changes, and by utilizing this cycle change, a rapid change in the outside air temperature is indirectly reflected. It is intended to perform the dew condensation removing operation by detecting the dew condensation caused by the depletion detection.

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

When the rate of decrease of the temperature cycle is large, the outside air temperature is drastically decreased, and the temperature of the rice cooking container is drastically decreased. For this reason, it can be determined that the saturated vapor pressure in the rice cooking container also decreases in accordance with the temperature and the excess vapor condenses to cause dew condensation on the inner surface of the rice cooking container. The dew condensation removing operation is sufficient as long as it is an operation capable of removing the dew condensation generated in the rice cooking container. For example, it is conceivable to heat the rice cooking container for a short time by using a rice cooking heating means or the like to evaporate the dew condensation on the inner surface of the rice cooking container. It is also possible to suck saturated steam in the rice cooking container to reduce the wetness of the steam in the rice cooking container.

The present invention can be applied, for example, to various rice cookers configured to keep the cooked rice warm after it is cooked. Further, the rice cooker is not limited to the rice cooker for general households, but may be a rice cooker for business use used in a restaurant, a lunch factory, or the like. There is no particular limitation on the rice cooking heating means for performing the rice cooking operation and the heat retaining and heating means for performing the heat retaining operation, and it is possible to employ one by burning gas such as a gas burner, or one by electricity such as an electric heater or an induction heating device. . In addition, the rice cooking heating means and the heat retention heating means can be used together in one device. In addition, when performing the dew condensation removal operation by heating, in order to prevent deterioration of the cooked rice due to heat, the cooked rice in the cooked rice container 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 consider the deterioration of the cooked rice due to heat.
According to the invention described in claim 3, the rice cooking container for accommodating cooked rice, the rice cooking heating means for heating the rice cooking container, and the heater are ON / OFF controlled to intermittently heat the rice cooking container to a predetermined temperature. Insulation heating means to maintain the temperature,
A rice cooker comprising a temperature detecting means for detecting the temperature of a rice cooking container and a control means for controlling the operation of the heat retaining and heating means, which detects the number of ON-OFF repeated operations of the heater per predetermined time, When the operation number detection and comparison means for comparing with the previously detected number of repeated operations is provided, the operation number detection and comparison means detects that the increase rate of the number of repeated operations of the heater is equal to or more than a predetermined value. It is characterized in that it is judged that dew condensation has occurred in the rice cooking container due to a large decrease rate of the outside air temperature, and control is performed to perform a dew condensation removing operation for removing the dew condensation in the rice cooking container.

The invention described in the claims includes:
Focusing on the fact that there is a fixed relationship with the number of times the heater is turned on and off, the dew condensation operation is performed by indirectly detecting the rate of decrease in the outside air temperature.
When the outside air temperature sharply decreases, the temperature of the rice cooking container also sharply decreases, and the ON-OFF operation cycle of the heater also decreases. Therefore, by detecting the number of repeated operations of the heater per predetermined time and calculating the increase rate of the number of operations, it is possible to indirectly detect the decrease rate of the outside air temperature and detect the occurrence of dew condensation.

In order to detect the number of times of operation, it is possible to employ a counter which is interlocked with ON operation or OFF operation of the heater. In addition to the counter, a timer for measuring a predetermined detection time, a storage unit for storing the number of previously detected operations, a calculation unit for obtaining a ratio with the number of previously detected operations, and the like are provided. The number-of-times detection / comparison means is configured.

The rate of increase in the number of operations 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 repeated operations.
Then, the generated dew condensation is quickly removed to prevent the rice from sticking. Further, by removing the dew 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 it can be applied to a gas rice cooker, a heater heating type electric rice cooker, an electromagnetic induction heating type rice cooker, and the like. A control means incorporating a microcomputer can be adopted as the control means for controlling the rice cooking heating means and the heat retention heating means. Further, the dew condensation removing operation is not particularly limited, and for example, as in the invention described in claim 4, it can be performed by temporarily heating the rice cooking container by using the rice cooking heating means. Further, a heating means for removing the dew condensation may be separately provided to temporarily heat the rice cooking container.

Further, the rice cooking heating means and the heat retention heating means are not limited to one system, and may be constructed by combining systems using gas, electricity and the like. While a gas burner is adopted as the rice heating means, an electric heater can be adopted as the heat retention heating means.

[0023]

By detecting the rate of change of the outside air temperature by utilizing the change in the temperature change cycle of the temperature controlled object, the temperature detecting means for detecting the change in the outside air temperature becomes unnecessary. Therefore, the control operation corresponding to the change in the outside air temperature can be achieved without increasing the manufacturing cost.

Further, since the outside air temperature can be detected by utilizing the temperature controlled object itself which is heated or cooled while being affected by the outside air temperature, it is not necessary to consider the influence of the heating means, the cooling means, etc. The outside air temperature can be detected quickly and accurately. In particular, in the heat retention operation of the rice cooker, it is possible to immediately evaporate and remove the generated dew condensation by rapidly detecting that the outside air temperature has dropped sharply. For this reason, dew condensation does not accumulate on the bottom of the rice cooking container and the cooked rice does not become sticky.

Further, since the accumulation of dew condensation is eliminated, it is possible to prevent the generation of offensive odor over a long period of time. Therefore, the cooked rice can be kept warm for a long time without deteriorating the taste.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an outline of the rice cooker according to the present embodiment. In the present embodiment, a gas burner is adopted as the rice cooking heating means for performing the rice cooking operation,
The present invention is applied to a rice cooker that employs an electric heater as a heat retention heating means for performing a heat retention operation.

As shown in FIG. 1, a rice cooker 1 contains a rice cooking container 2 for containing rice and the like, an outer container 3 for accommodating the rice cooking container 2, and an openable / closable attachment to the outer container 3. The lid 4, the gas burner 5 provided below the bottom of the rice cooking container 2, the electric heater 7 provided so as to surround the flame mouth portion 6 of the gas burner 5, and the rice cooking container 2
And a temperature sensor 8 provided so as to come into contact with the bottom surface of the. An ignition device 9 is arranged near the flame mouth portion 6.

The operation of the gas burner 5 and the electric heater 7 is controlled by a control device 10 having a micro computer, and the operation of the gas burner 5 is controlled in accordance with a set rice cooking pattern to control ignition timing, extinguishing timing,
The rice is cooked while controlling the heat power. After the rice cooking operation is completed, the electric heater 7 is ON-OFF controlled 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 cooking container 2 and the outer container 3 surrounding the rice cooking container 2 so that the rice cooking container 2 can be heated from the surroundings by the exhaust gas passing through the gap 11. It is a so-called Tsutsumi-cooking type rice cooker. The gap 11 is also used as an exhaust heat passage for heat retention by the heater 7, communicates with the exhaust heat space 12a through a communication port 12 provided in the upper portion of the outer container 3, and the exhaust heat space 12a is , Is communicated with the outside through an exhaust port (not shown) provided on the side surface of the rice cooker. For this reason, the rice cooking container 2 is easily affected by the outside air, and when the outside air temperature changes abruptly, the temperature of the peripheral wall portion of the rice cooking container 2 decreases, and dew condensation is likely to occur on the inner surface of the rice cooking container.

In the present embodiment, the method for detecting the rate of change of the outside air temperature according to the present invention is applied to the above conventional rice cooker. FIG. 2 is a flowchart showing the flow of control according to the present invention. First, after extinguishing the gas burner 5 and ending the rice cooking operation (S101), K = 1 and M = 1 are given as initial values of the 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 operations detected in advance.

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 being turned on (S105). When the temperature of the rice cooking container 2 rises to 72 ° C. or higher, the heater 7 turns off.
FF is performed (S107). In the present embodiment, the K of the memory is linked with the OFF operation of the heater 7.
Is replaced with K + 1 (S108). The initial value of K is 1
Therefore, K = 2 in this state.

The ON / OFF operation of the heater 7 is repeated until the count timer times out,
The value of K increases. In the present embodiment, the value of the count timer is set to 30 minutes. When the count timer times out (S109), the control device 1
K / M is obtained by the operation number detecting and comparing means within 0. Since the initial value 1 is included in M above, K / M is 2
Get bigger.

In the present embodiment, based on the temperature cycle of the rice cooking container depending on the outside air temperature, the dew condensation occurrence condition when the outside air temperature changes abruptly is defined as the operation number increase rate K / M ≧
It is set to 1.2, and when the value of K / M is 1.2 or more, control is performed to start the dew condensation removing operation according to the present invention. Since the temperature of the rice cooking container 2 drops sharply from the rice cooking temperature before the first operation of the heater 7 after rice cooking, dew condensation may occur. In the present embodiment, 1 is given as the initial value of M so that the dew condensation removing operation is performed after the heater 7 is first operated after the completion of the rice cooking operation.

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 at the same time as the ignition of the gas burner 5 (S112), and about 10
The rice cooking container 2 is heated for 2 seconds. After heating for 10 seconds and the ignition timer has timed out (S113), the gas burner 5 is extinguished and the dew condensation operation is completed (S11).
4).

In conjunction with the completion of the dew condensation removing operation, the previously detected number of heaters is stored in the memory M, and K is returned to the initial value 1 (S115). After the replacement of the memory is completed, the mode returns to the normal heat retention mode, and when the temperature of the rice cooking container 2 becomes 68 ° C. or lower, the heater 7 is repeatedly operated and the count timer is started to change the number of times the heater 7 is operated. To detect.

In detecting the number of operations 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 cooking container. Also, the above K /
When the value of M is 1.2 or less, the value of the memory M and the value of the memory K are exchanged without performing the dew condensation operation, and the determination is made after the subsequent detection of the number of times of heater operation. ing.

Therefore, the number of times the heater has been actuated detected immediately before is stored in M, and this value is compared with the detected value of the number of times the heater has been actuated next to perform control. The value of K / M of 1.2 or more means that the cycle of temperature change of the rice cooking container is reduced by 20% or more, and the outside air temperature sharply decreases, causing dew condensation in the rice cooking container. It is considered that In addition, the value of the above-mentioned operation frequency increase rate K / M which is a reference of control is not limited to 1.2, and can be changed according to the capacity of the rice cooking container, the heat retention temperature, the rice cooking amount, and the like.

By performing control based on the rate of decrease in the temperature cycle of the rice cooking container, in particular, based on the rate of increase in the number of times the heater 7 is operated, it is possible to use a highly accurate water drop generation detection sensor, etc. It is possible to detect the occurrence of dew condensation due to the rapid decrease in the outside air temperature, and it is possible to control the dew condensation removal operation by the detection. Further, 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, dew condensation does not accumulate on the bottom of the rice cooking container and the cooked rice does not become sticky.

Further, since the above-mentioned dew condensation is eliminated, it is possible to prevent the offensive odor from being generated for a long time. Further, since the rice cooking container is temporarily heated, it is possible to keep the cooked rice warm for a long time without deteriorating the taste. On the other hand, in the dew condensation removing step, since the rice cooking container is only temporarily heated by the heat power for removing the dew condensation, the quality of the cooked rice is hardly changed.

The present invention is not limited to the above embodiment. In the embodiment, the dew condensation removing operation is performed immediately after cooking rice, but the dew condensation removing operation may be controlled under normal conditions. Further, the number of times of operation is counted in conjunction with the OFF operation of the heater 7, but it may be configured to count in conjunction with the ON operation of the heater 7.

Further, the time for detecting the number of times the heater is operated is not limited to the embodiment, and can be changed according to the operation cycle or the like. The dew condensation removal operation is not limited to the one in which the dew condensation is evaporated by heating strongly for a long time as in the above-described embodiment. For example, the saturated water vapor is sucked to prevent dew condensation. You can also

[Brief description of drawings]

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

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

[Explanation of symbols]

1 ... rice cooker 2 ... rice cooking container 5 ... Gas burner 7 ... Electric heater 10 ... Control means

Claims (4)

(57) [Claims] 1. A method for detecting the rate of change of the outside air temperature on which a temperature controlled object configured to maintain a predetermined target temperature is placed, the heating or cooling operation being performed while being affected by the outside air temperature. A temperature change cycle of the temperature control target that is periodically changed by being added intermittently is detected, and a change rate of the outside air temperature is detected using the change rate of the temperature change cycle. A method to detect the rate of change of temperature. 2. A rice cooker comprising a rice cooking container for storing cooked rice and heating the rice cooking container, and performing a rice cooking operation for heating the rice cooking container and a heat retaining operation for heating the rice cooking container to keep it at a predetermined temperature. A method of heat retention, which detects the temperature change cycle of the rice cooking container that changes due to the outside air temperature and the above-mentioned heat retention operation, and when the rate of decrease of this temperature cycle exceeds a predetermined value,
A method of keeping heat in a rice cooking container, characterized in that it is judged that dew condensation has occurred in the rice cooking container due to a large decrease in the outside air temperature, and a dew condensation removing operation is performed to remove the above-mentioned dew condensation formed in the rice cooking container. . 3. A rice cooking container for containing cooked rice, a rice cooking heating means for heating the rice cooking container, and a heater ON-OF.
By F control, a heat retaining / heating means for intermittently heating the rice cooking container to maintain it at a predetermined temperature, a temperature detecting means for detecting the temperature of the rice cooking container, and a control means for controlling the operation of the heat retaining / heating means. A rice cooker comprising: a heater for detecting the number of times the heater is turned on and off repeatedly for a predetermined period of time; When it is detected by the comparison means that the rate of increase in the number of times the heater has been repeatedly operated 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 dew condensation has occurred in the rice cooking container. A rice cooker characterized by being controlled to perform a dew condensation removing operation for removing dew condensation in a rice cooking container. 4. The rice cooker according to claim 3, wherein the dew condensation removing operation is performed by temporarily heating the rice cooking container using the rice heating heating means.