JP5304043B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker having a heat retaining function and utilizing steam.

  Conventionally, in a general household rice cooker, heating by a pot heating means arranged at the bottom of the pot in order to heat the rice and water in the pot is mainly performed, and heating by the heating means in the lid is performed in the pot. It was auxiliary heating because it passed through the space above the rice and water.

  As a result, the rice in the upper layer in the pan was insufficient in heating amount, and the rice and water in the pan could not be heated uniformly.

  In addition, in rice cooking, the water in the pan is almost gone, and in the steaming process, which is the final process of cooking rice, the rice starch is gelatinized. , Essential for cooking delicious rice.

  However, if the heating is continued in this step, the rice near the bottom of the pan will burn, so the heating is often weakened.

  As a means to solve this, prevent insufficient gelatinization of rice due to weakening of heating, and improve rice cooking performance, an induction heating coil that is a high heat source is provided on the lid, and the rice from above the pan opening There was a rice cooker that heated.

  That is, as shown in FIG. 2, reference numeral 101 denotes a main body case, and a bottom plate 103 having support legs 102 is fixed to the lower surface.

  Reference numeral 104 denotes a protective frame made of heat-resistant plastic, and a collar portion 105 provided on the upper peripheral edge is fixed to the upper surface of the main body case 101.

  Reference numeral 106 denotes a bottom surface heating induction coil mounted on the lower bottom portion of the protective frame 104, and 107 denotes a side surface heating induction coil installed on the lower side of the protective frame 104, which has a magnetic metal layer accommodated in the protective frame 104. The pan 108 is heated by the bottom heating induction coil 106, and the contents of the rice and water in the pan 108 are cooked.

  Reference numeral 109 denotes a temperature sensor mounted in a through hole provided at the center of the bottom surface of the protective frame 104, and 110 denotes a lid having a knob 111, which is detachably mounted on the collar portion 105 at the upper end of the protective frame 104. The inner cover 112 made of heat-resistant plastic is fixed through a heat insulating material 113.

  Reference numeral 114 denotes an inner lid that is detachably attached to the inner cover 112 by means of a pin 115, and a peripheral portion of the inner lid is placed on the collar portion 105 of the pan 108 to cover the pan 108.

  Reference numeral 116 denotes a main body-side upper induction coil installed on the inner surface of the collar portion 105 of the protective frame 104, and is connected to a power supply portion (not shown) in the main body case 101.

  Reference numeral 117 denotes a lid-side induction coil that is excited by the main body-side upper induction coil 116 and is attached to a portion of the lid 110 facing the main body-side induction coil 116.

  The electric current excited by the lid-side induction coil 117 flows to the induction coil 118, and the magnetic flux heats the induction plate 119 formed of a magnetic metal plate, so that rice cooking heating or heat insulation heating from the upper part in the pan 108 can be performed. (For example, refer to Patent Documents 1 and 2).

  However, in the conventional configuration, the rice in the upper layer in the pan is directly heated by convection heat transfer (heat transfer) and radiant heat transfer of the heating plate by the operation of the induction coil. The phenomenon that water of rice evaporates and dries occurs.

  In other words, if heating is continued from above the pan to a temperature at which the entire rice in the pan can ensure sufficient rice cooking performance, the upper layer of rice in the pan will dry and conversely lose its taste.

  For this reason, after all, sufficient heating could not be performed and the taste was not perfect in the whole rice in the pan.

  Moreover, in order to promote gelatinization of rice and improve rice cooking performance, the amount of heating must be increased as the amount of cooked rice increases.

  However, as the amount of cooked rice increases, the upper layer of rice gets closer to the heating plate and the rice becomes easier to dry. Therefore, there is a problem that a contradiction arises in that heating must be weakened.

  Then, in addition to the pan, the pan heating means for heating the pan, and the lid for covering the opening of the pan, a rice cooker including steam generating means and steam heating means can be found (see, for example, Patent Document 3).

  Thereby, high-temperature steam having a boiling point (100 ° C.) or higher of water at atmospheric pressure is supplied to the rice. Hereinafter, unless specifically limited, such steam at 100 ° C. or higher is referred to as high-temperature steam.

  When the high-temperature steam adheres to rice having a temperature lower than 100 ° C., it condenses, generates heat, and heats the rice. That is, the heat energy required to advance gelatinization of rice starch is supplied to the rice by a pan heating means and high-temperature steam to promote gelatinization.

High-temperature steam condenses on the surface of rice at a temperature lower than 100 ° C. and becomes moisture, giving large heat energy. However, the heat energy given to rice at 100 ° C. or higher is small, so the rice does not dry.
JP-A-5-84126 JP-A-6-62956 JP 2003-144308 A

  However, in the conventional configuration, the water storage unit and the water storage unit heating unit are provided as the steam generation unit, but during the heat retention, water in the water storage unit is sterilized and heated in order to prevent germs from growing and decaying in the water in the water storage unit. At this time, the water evaporated from the water storage part is likely to condense on the steam path, and when the condensed water is dripped onto the rice, the rice has a problem that it loses its taste in a bowl shape.

  This invention solves the said conventional subject, provides the rice cooker which reduced the water | moisture content dripping to the rice during a heat retention, and improved the heat retention performance.

In order to solve the conventional problems, the present invention comprises a pan that is detachably accommodated in a main body having an open top surface, a lid that covers the main body so as to be freely opened and closed, a pan heating means that heats the pan, Supplying steam to the pan, a water storage unit disposed on the upper surface of the main body, and a steam generation unit having a water storage unit heating unit for heating the water storage unit, and a lid open / close detection unit for detecting the open / closed state of the lid, When the lid opening / closing detection means does not detect the opening of the lid after rice cooking, the water storage section heating means performs sterilization heating of the water in the water storage section after 12 hours , and the lid opening / closing detection means opens the lid. when detecting, the conduct sterilization heating of the water in the water storage section by the reservoir heating means after the 6 hours is a short predetermined time than 12 hours has elapsed, and the predetermined time is 12 hours
If the heat retention time is longer, it is set to 5 hours .

  This improves the reliability when keeping warm for a long time, reduces the frequency of sterilization of the water reservoir until the lid is opened after cooking rice, and the moisture evaporated from the water reservoir condenses on the steam path and drops on the rice. Reduction can be reduced and heat retention performance can be improved.

  The rice cooker of the present invention is sterilized and heated in accordance with the state of the water storage part in the steam generating means during the heat retention while improving the reliability during the heat retention for a long time while performing the rice cooking using the steam for cooking the rice. By reducing the frequency, moisture evaporated from the water storage unit is condensed in the steam path, and the taste reduction due to dripping on the rice is reduced, and the heat retention performance is improved.

The first aspect of the invention is to supply a steam to the pan, a pan that is detachably housed in a main body having an open upper surface, a lid that covers the main body so as to be opened and closed, a pan heating means for heating the pan, and the pan. A steam generation unit having a water storage unit disposed on the upper surface of the main body, and a water storage unit heating unit for heating the water storage unit, and a lid open / close detection unit for detecting the open / closed state of the lid, and after cooking rice, the lid open / close detection unit when detecting no cover opening, if the 12 hours the the reservoir heating means carried sterilized heating of the water in the reservoir after a lapse, the cover opening and closing detection unit detects the open lid, the 12 by the reservoir heating means after a lapse of 6 hours a short predetermined time than the time to implement the sterilization heating of the water in the water storage section, and the predetermined time is kept longer than 12 hours longer when 5 hours Is set.

  During cooking, the water storage section is heated by the water storage section heating means and is kept at about 100 ° C. while steam is generated, so that most germs are sterilized.

  Moreover, during cooking, since the inside of the pan also holds 100 ° C. for about 20 minutes, most of the various germs are sterilized also in the pan.

As a result, if the lid is kept closed after cooking, miscellaneous germs will not enter the water storage part of the rice cooker. The possibility is low, and sterilization heating in the reservoir is not performed until 12 hours have elapsed until the lid is opened.

Once the lid is opened, germs floating in the air are mixed in. Therefore, in order to prevent the propagation of the germs, the water in the water storage section is sterilized and heated after a predetermined time shorter than 12 hours .

  However, if the incubation is continued for a long period of time, even if the lid is closed, a few remaining bacteria will propagate, and after the lid is opened, there is a possibility that the propagation will spread further and rot.

  Therefore, the longer the heat retention time is, the shorter the predetermined time is, while improving the reliability at the time of heat retention, reducing the frequency of sterilization of the water storage part until the lid is opened after cooking, and the water evaporated from the water storage part is a steam path It is possible to reduce the deterioration of the taste caused by condensation on the rice and dripping on the rice, and to improve the heat retention performance.

In a second aspect based on the first aspect, sterilization heating of the water in the water storage section after 12 hours has elapsed is performed every 6 hours of the first predetermined time, and the lid open / close detection means opens the lid. If detected, sterilization heating of the water in the reservoir is performed every second predetermined 5 hour cycle shorter than the first predetermined time, and the first or second predetermined time cycle is: By setting the temperature to be shorter as the heat retention time is longer, while further improving the reliability during long-term heat retention, the water sterilization frequency until the lid is opened after cooking is reduced, and the water evaporated from the water vapor is vaporized. Condensation on the path and drop in taste due to dripping on the rice can be reduced, and the heat retention performance can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
As shown in FIG. 1, the rice cooker body 1 includes a pot 2 for storing rice and water, a pot heating means 3 for heating the bottom and sides of the pot 2, and a pot temperature detecting means for detecting the temperature of the pot 2. 4, a lid 5 covering the opening above the pan 2, and steam generating means 6 for generating steam for heating rice cooking.

  The lid 5 is provided with an inner lid 7 that seals the upper opening of the pan 2, and an inner lid heating means 8 that heats the inner lid 7.

  A steam cylinder 9 that discharges the internal steam to the outside of the main body 1 is provided at the opening on the top surface of the pan 2.

  By arranging a spherical steam valve 10 made of plastic, for example, in the steam cylinder 9, during steaming, the steam valve 10 moves upward by the power of the steam, and the steam is discharged out of the main body 1 and kept warm. Since the steam valve 10 is located at the lower part of the steam cylinder 9 and closes its lower hole 11, the bacteria floating in the air outside the main body 1 are stored in the pot 2 and the water storage part of the steam generating means 6. 12 is more difficult to enter.

  The steam generating means 6 has a water storage section 12, a water storage section heating means 13, and a water storage section water amount detection means 14, and is installed in the lateral direction of the pan 2 on the upper surface of the main body. The water storage unit water amount detection means 14 captures the length of time of temperature change of the water storage unit according to the water amount in the water storage unit 12 and estimates the water amount, or a method of measuring the weight of the water storage unit 12 and the main body 1. Various methods are conceivable.

  Moreover, the steam path 15 for supplying the vapor | steam generated from the water storage part 12 in the upper direction in the pan 2 in the rice cooking process is provided.

  The steam path 15 communicates and connects the upper opening of the water storage unit 12 and the upper part of the pot 2, and penetrates the inner lid 7 and faces the upper part of the pot 2.

  When the rice cooking process is started, the control means 16 controls the pot heating means 3, the inner lid heating means 8, and the water storage section heating means 13 according to a predetermined program to perform rice cooking.

  The control unit 16 determines whether the lid 5 is opened or closed based on an output signal from the lid opening / closing detection unit 17.

  In addition, the pan heating means 3, the inner lid heating means 8, and the water reservoir heating means 13 are based on induction heating, a sheathed heater, or the like, and are not particularly limited.

  The operation of the above configuration will be described below.

  When the user sets rice and water in the pan 2 and sets a predetermined amount of water (for example, 50 ml) in the water storage unit 12, turns on the rice cooker, and presses the rice cooking start button (not shown), The process is started.

  When the rice cooking process starts, the pan heating means 3, the inner lid heating means 8, and the water storage section heating means 13 start heating according to a predetermined program.

  During cooking, water in the water storage unit 12 evaporates by heating of the water storage unit heating means 13 and flows into the steam path 15 as steam at about 100 ° C.

  This steam is further heated to a steam exceeding 100 ° C. by the inner lid heating means 8, and the amount of heat necessary for the rice is given from above the pot 2. When the rice cooking process ends, the process automatically shifts to the heat retaining process.

  In the rice cooking process, by supplying heated steam having a boiling point of water (100 ° C.) or higher to the rice under atmospheric pressure, the rice is not dried even in the steaming process.

  Moreover, when the steam is supplied at a temperature of 100 ° C. or lower, water stays attached to the surface of the grain of rice, but since it is a steam of 100 ° C. or higher, it has the energy necessary to advance the gelatinization of rice, and promotes gelatinization. The rice cooking performance can be improved.

  In addition, an optimum heating amount can be set regardless of the amount of cooked rice.

  In the heat retaining step, the higher the temperature at which the cooked rice is warmed, the more noticeable the phenomenon that is disliked by the warming odor and the warming such as yellowing that causes the cooked rice to turn yellow.

  Therefore, in the heat retention process, the temperature of the cooked rice is maintained in a temperature range of about 60 to 75 degrees suitable for heat retention. In this temperature range, the lower the temperature of the cooked rice, the more the phenomena such as the warming odor and yellowing can be alleviated.

  In the heat retaining step, when the lid 5 cannot be opened for a first predetermined time (for example, 12 hours), the water in the water storage section 12 is heated by the water storage section heating means 13 and boiled for about 5 minutes. Sterilization heating is performed.

  Thereby, when the microbe which remain | survived in the pan 2 or the water storage part 12 propagates, it can sterilize and can prevent corruption.

  Further, when the lid cannot be opened even after sterilization heating of the water storage section 12, sterilization heating is performed for each first predetermined time cycle.

  Thereby, even when a user keeps the heat for a long time without opening the lid 5, it is possible to continuously sterilize the germs remaining in the pot 2 and the water storage unit 12 and breeding.

  Here, during cooking rice, the inside of the water storage unit 12 is maintained at about 100 ° C. while water is evaporated by the water storage unit heating means 13, so that most bacteria are sterilized.

  Moreover, since the inside of the pan 2 is kept at 100 ° C. for about 20 minutes, most of the miscellaneous bacteria therein are also sterilized.

  Therefore, there is little possibility that the germs in the pot 2 will propagate in the water reservoir 12 through the steam path 15.

  In addition, in the state where the lid 5 is closed, the bacteria floating in the air outside the main body 1 are unlikely to enter the water storage section 12, so that there is little possibility of being spoiled even if the water temperature is lowered.

  However, once the lid 5 is opened, germs floating in the air are mixed, so that there is a high possibility that the germs will propagate and decay in the water storage section 12.

  Therefore, after completion of the rice cooking process, the second predetermined time shorter than the first predetermined time after the opening of the lid 5 is detected by the output signal from the lid opening / closing detection means 17 constituted by the magnet 18 and the reed switch 19. At the time of the heat retention process (for example, 6 hours), the water in the water storage section 12 is heated by the water storage section heating means 13 and boiled for about 5 minutes to perform sterilization heating.

  Thereby, after cooking rice, until the lid 5 is opened, the sterilization heating frequency of the water in the water storage unit 12 is reduced, so that the water evaporated from the water storage unit 12 during this time is condensed in the steam path and dripped onto the rice. It is possible to reduce the deterioration of the taste caused by the heat and improve the heat retaining performance.

  At this time, since the frequency of sterilization heating until the user opens the lid 5 is reduced, it goes without saying that energy saving for sterilization heating is realized.

  Furthermore, when the heat retention time exceeds 12 hours, the second predetermined time is set shorter than the case where the heat retention time is 12 hours or less (for example, 5 hours).

  Thereby, in the long-time heat retention in which bacteria propagate more, it is possible to sterilize at an early stage and to suppress the proliferation of bacteria, so that the reliability can be improved.

  Needless to say, the heat retention time need not be limited to 12 hours, and can be varied according to the environment in which it is used.

  When the heat retention time exceeds 12 hours, the first predetermined time or the first predetermined time cycle is also set shorter than the case where the heat retention time is 12 hours or less (for example, 10 hours).

  As a result, even when the lid 5 cannot be opened, in the case of long-term heat retention in which the remaining bacteria may propagate, it is possible to sterilize at an early stage and suppress the growth of bacteria, thereby improving the reliability. Can do.

  Needless to say, the heat retention time need not be limited to 12 hours, and can be varied according to the environment in which it is used.

  Moreover, the heating amount of the water storage part 12 by the water storage part heating means 13 in the sterilization heating is such that the water amount determined by the water storage part water amount determination means 14 is a fixed amount (for example, 1/5 of a predetermined amount of water stored in the water storage part 12). If the amount is less than about 10 ml in the present embodiment, the amount of bacteria to propagate is small, so the boiling is set to about 2 minutes.

  As a result, when the amount of water in the water storage unit 12 is small, the amount of water evaporated from the water storage unit is reduced, and the water content evaporated from the water storage unit is condensed in the steam path and further reduced in taste due to dripping onto the rice. In addition, the heat retention performance can be improved.

  Needless to say, when the amount of water in the water storage section 12 is small, the amount of heat during sterilization heating is reduced, thereby reducing power consumption in sterilization heating and realizing energy saving.

  The amount of water in the water storage unit 12 is smaller than the fixed amount (for example, 10 ml) set for boiling for about 2 minutes by the water storage unit water amount determination means 14, and the amount of water that may cause failure or deformation around the water storage unit 12 (for example, 2ml) ) When it is determined as follows, the water storage section 12 is not sterilized and heated by the water storage section heating means 13.

  Therefore, when the amount of water in the water storage unit 12 is small, it is possible to prevent the periphery of the water storage unit from being overheated by sterilization heating and failing or deforming, thereby improving reliability.

  Here, the sterilization heating is boiled for about 5 minutes, when the amount of water is a certain amount (for example, about 10 ml) or less, boil for about 2 minutes, and when the amount of water is less (for example, about 2 ml) or less, sterilization heating is not performed. However, the amount of water, sterilization heating time, and temperature are not limited to this as long as sterilization heating in the water storage section 38 can be performed and failure or deformation can be prevented. Heating may be performed.

  Moreover, when the water amount in the water storage part 12 is less than predetermined by the water storage part water amount detection means 14, the water storage part 12 is not heated by the water storage part heating means 13.

  Thereby, the failure and deformation | transformation by the overheating around a water storage part when the amount of water of a water storage part is less than predetermined amount during rice cooking can be improved, and reliability can be improved.

  As described above, the rice cooker according to the present invention reduces the sterilization heating frequency according to the state of the water storage unit in the steam generating means during the heat retention while improving the reliability during the heat retention for a long time. Since the moisture evaporated from the water is condensed in the steam path and drops on the rice, it can reduce the deterioration of the taste and improve the heat retention performance, so it has not only a rice cooker but also a general heat retention function and uses steam It is also useful for cookers.

Sectional drawing of the rice cooker in Embodiment 1 of this invention. Cross section of conventional rice cooker

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Pan 3 Pan heating means 5 Lid 6 Steam generation means 12 Water storage part 13 Water storage part heating means 14 Water storage amount determination means 17 Lid opening / closing detection means

Claims (2)

A pan that is detachably housed in a main body with an open top surface, a lid that covers the main body openably and closably, a pan heating means that heats the pan, supplies steam to the pan, and is disposed on the top surface of the main body. A steam generation means having a water storage section and a water storage section heating means for heating the water storage section, and a lid open / close detection means for detecting the open / closed state of the lid, and the lid open / close detection means does not detect the lid open after cooking. The sterilization heating of the water in the water storage unit is performed by the water storage unit heating means after 12 hours have elapsed, and when the lid open / close detection unit detects the lid open, a predetermined time shorter than the 12 hours. 6 hours conduct sterilization heating of the water in the water storage section by the reservoir heating means after a lapse is, and the predetermined time is cooker set to 5 hours and the holding time is longer than 12 hours. The sterilization heating of the water in the water storage section after 12 hours is performed every 6 hours of the first predetermined time, and when the lid opening / closing detection means detects the lid opening, from the first predetermined time. The sterilization heating of the water in the water storage section is performed every short second predetermined five-hour cycle, and the first or second predetermined time cycle is set to be shorter as the heat retention time is longer. 1. The rice cooker described in 1.