JP2013202071A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker maintaining a just-cooked state by suppressing a heat insulation odor and drying in time of heat insulation.SOLUTION: A rice cooker includes: an overheated steam control means 6b controlling, by the output of a heater 32, an overheated steam temperature detected by an overheated steam temperature detection means 33 contacting with a steam overheating means 30 including the heater 32 and an steam overheating container 31, which overheats steam generated by a steam generation means 20; and a check valve 40 discharging steam inside a pot 2 to outside air, and not allowing the entry of outside air into the pot 2. The rice cooker can control a temperature of steam put into the pot 2 from a steam input port 4c to a first steam temperature 50 higher than a prescribed temperature and a second steam temperature 51 lower than the prescribed temperature.

Description

  The present invention relates to a rice cooker that quickly expels a thermal odor by superheated steam and further prevents rice from drying.

  In a general household rice cooker, a pot heating means for heating rice and water in the pot arranged at the bottom of the pot is the main heating means. When the inside of the pan is adjusted to a temperature of 60 ° C. to 70 ° C., which suppresses the growth of bacteria even when the cooked rice is kept warm, by heating the pan, the whole rice is kept at the temperature. At this time, the surface of the rice is not easily heated because it is away from the skin of the pot where heat from the pot heating means is most easily transmitted, and if the overheating is continued to keep the temperature of the rice surface warm, the vicinity of the bottom of the pan becomes overheated and the rice is dried. The taste had deteriorated by doing.

  In order to solve this problem, for example, as shown in FIG. 4, in addition to the heating by the pan heating means, a rice cooker that heats the rice by injecting hot steam into the pan from above the pan has been invented. (For example, refer to Patent Document 1).

  In FIG. 4, a rice cooker body 1 includes a pan 2 that is detachably mounted on the rice cooker body 1, a lid 3 that covers the top surface of the pan 2 so that it can be opened and closed, a pan bottom heating coil 5a that heats the pan, and a rice cooker body 1 The steam generating means 20, the water tank 21 and the water tank heating means 22 are installed in the interior. The water in the water tank 21 is heated by the water tank heating means 22 and boils. The water vapor generated in the water tank 21 is supplied to the pan 2 from the steam inlet 4 c through the steam pipe 24. As described above, the surface rice can be kept at the heat insulation temperature without drying.

  And in the sterilization process which maintains the inside of the pan 2 at a high temperature (for example, 80 ° C. or higher) intermittently for sterilization, the steam generation means 20 is automatically controlled to supply steam in order to prevent the rice from drying due to heating. It is possible to provide a rice cooker that is hygienic and can suppress the deterioration of the taste of the heat-retaining rice.

Japanese Patent No. 3757914

  However, in the configuration and operation of the conventional rice cooker, there is a problem that the rice is deteriorated because the effect of suppressing the drying and curing of the rice, which is greatly deteriorated in the heat insulation of the rice, and the heat retention odor cannot be sufficiently exhibited. .

  The present invention keeps cooked rice by preventing steam from drying and hardening by keeping steam at 100 ° C. or higher in the pan at the time of heat retention, and suppressing the heat retention odor to prevent the taste deterioration of the heat retention rice. The purpose is to provide a rice cooker that can be used.

  The inventors of the present invention have found the following as a result of intensive studies to solve the conventional problems.

  In other words, the warming odor of rice is the oxidative odor of fats and oils such as aldehydes generated by the oxidation of unsaturated fatty acids such as linoleic acid and oleic acid contained in rice. We found that it is effective to expel it from the pan by heating the upper space of the rice in the pan by introducing superheated steam into the pan to increase the saturated vapor pressure and lowering the partial pressure of the warm odor component. It was. Based on this finding, the present invention was conceived.

  In order to solve the above-mentioned conventional problems, the rice cooker of the present invention has a check valve in the steam port portion for discharging steam in the pan to the outside air so as to prevent the ingress of air from the outside air into the pan. Provided is a superheated steam control means for controlling the first steam temperature that is higher than the predetermined temperature and the second steam temperature that is lower than the predetermined temperature, so that the first steam temperature and the second steam temperature are provided. The steam was put into the pan intermittently.

  As a result, it is possible to quickly raise the saturated vapor pressure by efficiently raising the temperature of the space in the pan by introducing the steam at the first steam temperature, and at a second steam temperature lower than the first steam temperature. By adding the steam, the rice that has been dried due to the temperature rise due to the first steam temperature can be moisturized by the condensation of the steam.

  And when the steam is condensed, if the inside of the pan becomes negative pressure, the outside air will flow into the pan and the rice will dry in reverse, but the check valve can prevent the outside air from flowing into the pan. In addition, the heat retention odor can be removed and the rice can be moisturized.

  The rice cooker of the present invention can maintain the state of the freshly cooked rice by optimally keeping the temperature by controlling and supplying two steam temperatures according to the two purposes for pursuing the odor and keeping the moisture. A rice cooker that can be provided can be provided.

Side sectional view of the rice cooker in Embodiment 1 of the present invention. Side sectional view of the rice cooker in Embodiment 1 of the present invention. The graph which shows the pan upper space temperature at the time of the heat retention of the rice cooker in Embodiment 1 of this invention, and a superheated steam inlet temperature. Side sectional view of a conventional rice cooker

  1st invention is a rice cooker main body, the pan equipped to a rice cooker main body, the heating means which heats the said pan, the cover which covers a rice cooker main body, the pan temperature detection means which detects the temperature of the said pan, and a pan A steam port for discharging excess steam in the atmosphere to the outside, a check valve for preventing inflow from outside air into the pan from the outside of the steam port, and steam for heating the water to generate steam Generating means; steam superheating means for heating the steam generated by the steam generating means to 100 ° C. or higher to form superheated steam; and steam temperature detecting means disposed in the steam superheating means for detecting the steam temperature; A control means for controlling the heating means in accordance with a predetermined rice cooking sequence according to the output of the pan temperature detection means and / or the steam temperature detection means, and the steam temperature is controlled by controlling the temperature of the steam superheating means Rice cooker that can do Thus, the first steam temperature that is higher than the predetermined temperature and the second steam temperature that is lower than the predetermined temperature are provided at the time of heat retention, and the steam is introduced into the pan at each steam temperature. To provide a rice cooker that can maintain the state of freshly cooked rice by optimally keeping it warm by controlling two steam temperatures according to two purposes for chasing odor and keeping moisture. It is possible.

  In particular, the second aspect of the invention has a configuration in which the steam is charged at the second steam temperature after the steam is charged at the first steam temperature of the first invention, and this is repeated at predetermined time intervals.

  As a result, the second steam temperature lower than the first steam temperature for moisturizing the rice that has been dried by adding steam at the first steam temperature to expel the heat retaining odor and raising the temperature in the pan. It is possible to provide a rice cooker that can suppress drying by condensing on the surface of the rice, particularly by condensing the steam, and moisturizing the rice.

  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)
FIG. 1 shows a side sectional view of a rice cooker according to the first embodiment of the present invention.

  In FIG. 1, the rice cooker main body 1 is formed in a substantially cylindrical shape having an open top surface, and a protective frame 9 that is a pot storage portion is disposed inside the rice cooker main body 1. The pot 2 having the water level line drawn on the inner peripheral surface is detachably disposed. A pan bottom heating coil 5 a for heating the pan 2 is arranged outside the protective frame 9, and a pan side heating coil 5 b is arranged outside the side surface of the pan 2. The pan bottom heating coil 5a and the pan side heating coil 5b may be heaters instead of the heating coils.

  A lid 3 is attached to the top of the rice cooker body 1 so as to be freely opened and closed. The lid 3 is rotatably supported on the rear portion of the protective frame 9 via a hinge shaft 3a and is urged by a rotating spring 3b. At the other end of the lid 3, a hook button 1 a pivotally supported in front of the protective frame 9 is disposed to prevent the lid 3 from being opened. When the hook button 1a is fitted to the lid 3, the lid 3 is held by the hook button 1a without opening and is in a closed state.

  At the bottom of the lid 3, the steam outlet 4 b that discharges steam generated in the pot 2 during cooking and warming, and the discharge of steam from the pot 2 to the outside air are not obstructed, and conversely, the outside air enters the pot 2. An inner lid 4 having a check valve 40 for preventing the inflow of outside air is disposed, and an upper portion of the inner lid 4 is connected to the inner lid heating coil (heater) 5c for heating the inner lid 4 and the outside of the main body. The steam cylinder 10 is provided.

  Here, an umbrella type check valve is used as the check valve 40 in FIG. 1, and the check valve 40 made of rubber is pushed up to the outside air by steam rising from the steam port 4b when the inside of the pan 2 is positive. When the inside of the pan 2 has a negative pressure, the check valve 40 blocks the steam port 4b, so that outside air does not enter.

  The check valve 40 may be another rubber valve or a pressure regulating valve mechanism of a pressure rice cooker as shown in FIG. That is, a ball 42 having a predetermined weight for closing the steam port 4b, a rod 41a for pressing the ball 42 to connect the steam port 4b and the steam cylinder 10, and a cylinder 41b for controlling the pushing and pulling of the rod 41a. The pressure regulating valve mechanism is composed of a plunger 41, and the ball 42 is pushed by the vapor pressure in the pan 2 at the time of positive pressure, or the steam 41 to the outside air is controlled by pushing the ball 42 by controlling the plunger 41. When the discharge is realized and the inside of the pan 2 has a negative pressure, the outside air does not enter the pan 2 by the ball 42 being drawn into the steam port 4b.

  A steam port packing 7 is disposed between the steam cylinder 10 and the inner lid 4 to prevent steam from flowing into the lid 3. Moreover, the inner cover packing 4a which contact | abuts on the outer peripheral part of the inner cover 4 and the upper surface of the flange part 2a of the pan 2 is arrange | positioned, and the vapor | steam which generate | occur | produces in the pan 2 during rice cooking and heat insulation is from steam outlet 4b. Prevents leakage to the outside.

The pan temperature detecting means 8 can detect the temperature of the pan 2 by heat conduction while being in contact with the substantially center of the bottom of the pan 2.

  The rice cooker body 1 includes a water tank 21 for storing water, a water tank heating means 22 for heating the water tank 21, and a water tank temperature detecting means 23 for detecting the temperature of the water tank 21. A configured steam generating means 20 is arranged. That is, the steam generating means 20 generates water by heating water.

  When the lid 3 is closed, the upper surface of the water tank is sealed with a packing (not shown) so that the generated steam does not leak.

  Inside the lid 3 is a steam superheater constituted by a heater 32 for superheating the steam generated by the steam generating means 20 to form superheated steam, and a cylindrical steam superheater vessel 31 containing part or all of the heater 32. Means 30 are provided.

  The steam generating means 20, the steam superheating means 30, and the pan 2 are in communication with the lid 3 closed.

  The superheated steam temperature detecting means 33 for detecting the temperature of the superheated steam is in contact with the steam superheated container 31, and the first steam whose temperature detected by the superheated steam temperature detecting means 33 is higher than a predetermined temperature. Superheated steam control means 6b for controlling the temperature 50 and the second steam temperature 51, which is lower than the predetermined temperature, is provided.

  About the rice cooker comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  After the user puts rice to be cooked and water corresponding to the amount of rice into the pan 2 and sets it in the rice cooker body 1 and closes the lid 3, a rice cooking start button (not shown) on the operation input display unit 12 is pressed. A rice cooking process is implemented by operating.

  The rice cooking process is largely divided into pre-cooking, cooking, boiling maintenance, and steaming in order of time. In the pre-cooking step, the heating means 5 is controlled so that the temperature of the pot 2 becomes a temperature suitable for water absorption of rice (for example, 60 ° C.), and the rice and water in the pot are heated.

  Next, in the cooking step, the pan 2 is heated with a predetermined amount of heat by the pan bottom heating coil 5a until the temperature of the inner lid 4 reaches a predetermined value (for example, 80 ° C.). The amount of cooked rice is determined based on the temperature rise rate at this time.

  In the boiling maintenance step, the pot bottom heating coil 5a is energized to heat the rice and water until the pot 2 has no water and the pot 2 temperature reaches a predetermined value exceeding 100 ° C.

  Next, in the steaming step, the rice is steamed by controlling the heating means 5 to such an extent that the temperature of the rice is maintained at a predetermined temperature (for example, 98 ° C.).

  The rice cooking process is completed as described above, and the rice in the pan 2 is in a state where it can be eaten with the gelatinization of starch being edible.

  When the rice cooking process ends, the rice cooker automatically shifts to a heat retaining process and is kept warm at a predetermined temperature (for example, 70 ° C.).

  Here, FIG. 3 is a graph showing the pan upper space temperature and the superheated steam inlet temperature when the rice cooker in the first embodiment of the present invention is kept warm.

  At this time, the heating control means 6a controls the pan bottom heating coil 5a so that the temperature detected by the pot temperature detecting means 8 is 70 ° C. Furthermore, the pan side heating coil 5b and the inner lid heating coil 5c are controlled by heating so that the steam generated by keeping the rice on the lower surface of the inner lid 4 and the side surface of the pan 2 is not condensed. The temperature of the lower surface of the lid 4 and the side surface of the pan 2 is kept high.

  By these heating, the rice in the pan 2 is dried with time, and the fats and oils such as unsaturated fatty acids contained in the rice are oxidized to generate a warm odor represented by aldehydes.

  In order to suppress the generation of the warming odor, it is effective to remove oxygen from the pot 2 and keep it warm in an oxygen-free state (oxygen partial pressure 0 mmHg) in order to suppress the oxidation reaction. However, in order to achieve an oxygen partial pressure of 0 mmHg, for example, the inside of the pan 2 must be evacuated, the air in the pan 2 can be replaced with nitrogen containing a predetermined concentration of steam, or the saturated vapor pressure must be 760 mmHg.

  However, when the vacuum (including the pressure drop) is applied, the moisture of the rice is evaporated and drying proceeds, and a nitrogen cylinder is required for nitrogen replacement. To achieve a saturated vapor pressure of 760 mmHg, the pot 2 must be kept at 100 ° C. is there. Both are difficult to realize as home appliances that store food.

  Therefore, in this embodiment, the superheated steam is controlled to the first steam temperature 50 by the superheated steam control means 6b and thrown into the pot 2 in order to drive out the heat retaining odor generated by oxidation at a predetermined saturated steam pressure. To do.

  As a result, the temperature of the upper space of the pan 2 can be increased efficiently by condensing steam on the lower surface of the inner lid 4 and the like, thereby increasing the saturated vapor pressure. At this time, excess steam and odor components present at a pressure higher than the partial pressure are discharged from the steam port 4b, and the warming odor can be reduced by the ventilation action.

  At this time, condensation occurs on the surface of the rice in the pan 2 to keep the moisture, and drying due to heat insulation can be prevented. However, since the upper space of the pan 2 becomes a high temperature of 70 ° C. or more due to the increase of the saturated vapor pressure, the rice is dried quickly.

  Therefore, by introducing superheated steam controlled to the low-temperature second steam temperature 51 into the pan 2, the steam is condensed in the rice without increasing the internal temperature of the pan 2, so that the rice is moisturized and dried. Suppress promotion. Moreover, since the inside of the pan 2 becomes negative pressure due to the condensation of steam, the outside air tries to enter the pan 2 from the steam port 4b. However, if this is entered, the cooling and drying of the rice are promoted by the outside air. Therefore, the moisture retention by steam is not effectively performed. Therefore, the check valve 40 prevents inflow of outside air and prevents drying of the rice due to inflow of outside air.

  The first steam temperature 50 is a temperature at which the upper space of the pan 2 quickly rises in the range where the rice is not dried or burnt, and the material and dimensions of the pan 2, the dimensions of the steam port 4 b, and the steam generating means 20. It depends on the amount of steam generated.

  Further, the second steam temperature 51 is set low so that the rice temperature is not increased. However, if the steam temperature is too low, condensation occurs at the steam inlet 4c and drops as water droplets on the rice, causing whitening of the rice. . The temperature is set within a range from the temperature at which no condensation occurs at the steam inlet 4 c to the second steam temperature 51 so that the steam can exist as steam in the pan 2.

As described above, in the heat retention of the rice cooker according to the present embodiment, the first steam temperature 50 is controlled in order to raise the saturated steam pressure and lower the partial pressure of oxygen and odor components to expel it from the pot 2. The heated superheated steam and the superheated steam controlled to the second steam temperature 51 in order to effectively moisturize the rice are intermittently introduced into the pan 2 to simultaneously reduce the heat retaining odor and suppress the drying of the rice. It is possible to provide a rice cooker that can be realized and maintain the state of freshly cooked rice.

  As described above, the rice cooker according to the present invention can be expected to have the effect of chasing odor components during heat retention and the moisturizing effect of the cooked food, and is effective for heating and keeping foods that generate odor due to heat retention.

DESCRIPTION OF SYMBOLS 1 Rice cooker body 2 Pan 3 Lid 4 Inner lid 4a Inner lid packing 4b Steam outlet 4c Steam inlet 5 Heating means 5a Pan bottom heating coil 5b Pan side heating coil 5c Inner lid heating coil 6 Control means 6a Heating control means 6b Superheated steam Control means 7 Steam port packing 8 Pan temperature detection means 9 Protective frame 10 Steam cylinder 12 Operation input display section 20 Steam generation means 21 Water tank 22 Water tank heating means 23 Water tank temperature detection means 24 Steam pipe 30 Steam superheat means 31 Steam superheat Container 32 Heater 33 Superheated steam temperature detection means 34 Superheated steam pipe 35 Superheated steam inlet packing 40 Check valve 41 Plunger 41a Rod 41b Cylinder 42 Ball 50 First steam temperature 51 Second steam temperature

Claims (2)

The rice cooker body,
A pan to equip the cooker body,
Heating means for heating the pan;
A lid covering the rice cooker body;
Pan temperature detecting means for detecting the temperature of the pan;
A steam port for discharging excess steam in the pan to the outside air;
A check valve for preventing inflow into the pan from outside air provided in the path of the steam port;
Steam generating means for generating steam by heating water;
Steam superheating means that superheats the steam generated by the steam generating means to 100 ° C. or higher to form superheated steam;
A superheated steam temperature detecting means disposed in the steam superheating means for detecting a steam temperature;
Control means for controlling the heating means according to a predetermined rice cooking sequence according to the output of the pan temperature detection means and or the superheated steam temperature detection means,
In the rice cooker that can control the steam temperature by controlling the temperature of the steam superheating means,
A rice cooker configured to provide a first steam temperature that is higher than a predetermined temperature and a second steam temperature that is lower than the predetermined temperature at the time of heat retention, and to input the steam into the pan at each steam temperature. 2. The rice cooker according to claim 1, wherein the steam is charged at the second steam temperature after the steam is charged at the first steam temperature, and this is repeated at predetermined time intervals.

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