JPH11192162A - Heat retaining kettle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of decomposition smell when heat is retained for a long time, when heat retaining is resumed after the heat retaining is temporarily suspended or when a lid body is frequently opened/closed and improve a heat retaining state by suppressing dew condensation around in a pot body. SOLUTION: The propagation of putrefying bacteria is suppressed by keeping the temperature of rice in a pot 5 high, e.g. 72 to 78 deg.C, when heat is retained. By keeping the temperature of a steam port 78 at 50 deg.C or higher, incursion of putrefying bacteria through the steam port being easy, the spreading of putrefying bacteria from the steam port 78 into the pot is prevented. By keeping the temperature of a surface opposite the pot 5 of a lid body 51 heated by a lid heater 62 slightly higher than that of rice, dew condensation around in the pot 5 is suppressed. This is especially effective when the pot 5 is subjected to electromagnetic induction heating by a heating coil 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating pot for keeping rice warm.

[0002]

The main problems in keeping rice warm include dryness, yellowing and stickiness, but the worst problem is the generation of odor. Odors that cause problems include the usual warm odor caused by oxidative deterioration of fats and amino-carbonyl reaction, as well as the putrefaction odor of rice (sour odor, sewage odor of rags, etc.) due to the growth of rot bacteria such as Bacillus subtilis. ). The heat retention odor is generated when the heat retention time is prolonged and causes a decrease in taste.
Putrid odor is a fatal problem that is not worth eating. It is said that putrefactive bacteria causing the putrefactive odor sporulate at 50 ° C to 55 ° C or higher and do not proliferate. For these reasons, it is common to maintain the temperature of rice at the time of heat retention at a predetermined temperature selected from the range of 55 ° C to 78 ° C. further,
As the temperature rises, the heat retention odor increases, so it is usually 69
C. to 73.degree. When keeping warm for more than 24 hours, temporarily reduce the temperature to 65 ° C to 69 ° C to reduce the heat retention odor.
The temperature was lowered to a certain extent to keep the temperature warm.

[0003] However, when the heat retention time is longer than 24 hours as described above, or when the heat retention is temporarily stopped due to a power failure or intentionally and the temperature is kept warm again from a cold state, It is considered that rot bacteria may be generated when the outside air enters by opening and closing the lid, and it is considered that improvement is necessary.

[0004] Another problem at the time of keeping the temperature warm is that dew is formed due to partial cooling in the pot, and the dew falls on the rice to cause white fluff (the rice becomes too wet due to excessive moisture). is there. In particular, in an insulated kettle that heats the pan by electromagnetic induction heating, the temperature around the pan is lower than the temperature of the pan because the pan directly generates heat, and the heat of the pan radiates outward, so the inside of the pan Although the high temperature is maintained in the portion with rice due to the heat capacity of this rice, the inner surface of the pot above the rice without rice has a large amount of dew due to the low temperature, and the dew condenses on the pot skin The dripping on the rice causes the surroundings in the pot to become extremely sticky, resulting in deterioration of the heat retention state.

[0005] The present invention is intended to solve such a problem, and it is possible to prevent corruption even when the heat is kept for a long time, when the heat is temporarily interrupted, or when the lid is frequently opened and closed. It is an object of the present invention to provide a warming pot capable of preventing generation of odor, suppressing dew condensation in a pot, and improving a heat retaining state.

[0006]

According to a first aspect of the present invention, there is provided an insulated pot having a pot, a cover for covering the pot, a pot heating means for heating the pot, and the lid. Lid heating means for heating the body and a steam port provided in the lid,
Heating means for maintaining the rice in the pan at a predetermined temperature by the pan heating means and maintaining the temperature of the lid and the steam port at a predetermined temperature by the lid heating means; When the temperature is stable,
The temperature of the rice in the pan is maintained at 72 ° C. to 78 ° C., and the temperature of the surface of the lid facing the pan is maintained slightly higher than the temperature of the rice.

[0007] As described above, by keeping the temperature of rice at the time of keeping the temperature (hereinafter, simply referred to as the keeping temperature) as relatively high as 72 ° C to 78 ° C, the proliferation of putrefactive bacteria can be surely suppressed. For example, when keeping warm for a long time, restarting warming after temporarily suspending warming, or even when a lot of putrefactive bacteria in the air enter the pot by opening and closing the lid frequently. In addition, the proliferation of putrefactive bacteria is suppressed, and the generation of putrefaction odor is prevented. At the same time, the heat retention temperature is relatively high as described above, and the temperature of the surface of the lid facing the pot is close to the heat retention temperature within a range higher than the heat retention temperature, so that dew condensation on the side surface inside the pot is suppressed. In addition, the stickiness of the rice due to the dew is prevented.

According to a second aspect of the present invention, in the heat retaining pot of the first aspect of the present invention, the heat retaining means keeps the temperature inside the steam port at 50 ° C. or more.

[0009] Since the steam port communicates with the outside, putrefactive bacteria easily enter, but spoilage odor is generated when putrefactive bacteria propagated in the steam port spread over the rice in the pot. On the other hand, if the temperature inside the steam port is maintained at 50 ° C. or higher, the growth of putrefactive bacteria in the steam port is suppressed, and the generation of putrefaction odor is prevented.

According to a third aspect of the present invention, in the insulated pot of the first or second aspect of the invention, the lid heating means simultaneously heats the surface of the lid body facing the pot and the steam port by one heat source. Things.

Thus, the prevention of the cooling of the steam port can be realized with a simple structure. According to a fourth aspect of the present invention, in order to attain the above object, the heating unit for electromagnetically heating the bottom and the lower side of the pan keeps the temperature of the rice in the pan at a predetermined temperature and covers the pan. A heat retaining means for keeping a temperature of a portion of the lid facing the pot at a predetermined temperature by a lid heating means provided inside the lid, wherein the temperature of the rice in the pot is kept at 72 ° C. While keeping the temperature at 78 ° C., the temperature of the portion of the lid facing the pot is kept slightly higher than the temperature of the rice.

By setting the heat retention temperature relatively high at 72 ° C. to 78 ° C., the proliferation of spoilage bacteria can be reliably suppressed. For example, when keeping warm for a long time, restarting warming after temporarily suspending warming, or even when a lot of putrefactive bacteria in the air enter the pot by opening and closing the lid frequently. In addition, the proliferation of putrefactive bacteria is suppressed, and the generation of putrefaction odor is prevented. In particular, in the case of the electromagnetic induction heating type as in the insulated pot of the invention of claim 4, the temperature of the inner surface of the pot above the rice without the rice tends to be low, but the heat retention temperature is relatively high as described above. In addition, since the temperature of the surface of the lid facing the pot is close to the heat retention temperature within a range higher than the heat retention temperature, dew condensation on the side surface in the pot is suppressed, and the stickiness of the rice due to the dew is prevented. .

According to a fifth aspect of the present invention, in the insulated pot of any one of the first to fourth aspects of the present invention, the lid heating means includes a tape formed of a member having good heat conductivity on a member forming an inner surface of the lid. The tape made of a member having good thermal conductivity is made approximately the same size as the member forming the inner surface of the lid.

Thus, the heat generated by the cord heater is transmitted to almost the entirety of the member forming the inner surface of the lid via a tape made of, for example, aluminum having good heat conductivity, and dew condensation on this member is suppressed. At the same time, by making the aluminum tape as large as possible, the possibility that the aluminum tape is peeled off and the cord heater separates from the member forming the inner surface of the lid is reduced. Therefore,
The risk of insufficient heating due to the cord heater separating from the member forming the inner surface of the lid is reduced.

According to a sixth aspect of the present invention, in the heat retaining pot of the fifth aspect of the present invention, a member forming an inner surface of the lid is made of stainless steel.

Although stainless steel has poor thermal conductivity, the heat generated by the cord heater is transmitted to almost the entire member forming the inner surface of the lid via the aluminum tape as described above.
The entire inner surface of the lid, including the portion without the code heater, is heated substantially uniformly.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a heating tank according to an embodiment of the present invention. The heating pot of this embodiment is also used as a rice cooker. In FIG. 1 showing an overall sectional view of a heat retaining pot, reference numeral 1 denotes a heat retaining pot main body, 2 denotes an outer frame which forms an outer shell of the heat retaining pot main body 1, and a bottom portion of the outer frame 2 covers an opening thereof, and the heat retaining pot main body. The bottom plate 3 forming the bottom shell of the first fitting is fitted and fixed. Further, inside the outer frame 2, a pot housing portion 4 as a bottomed cylindrical inner frame is disposed, and the pot 5 is detachably housed in the pot housing portion 4. The pan storage wall 6 that forms the side surface of the pan storage section 4 is formed integrally with the outer frame 2 that forms the upper portion of the pan storage section 4. As shown in FIG. 2, the outer frame 2 is mainly made of a synthetic resin 7 such as polypropylene that can withstand a rise in temperature during rice cooking and heat retention, and has a particle size of 5 μm to 1 μm.
It contains 10% to 50%, preferably 20% to 40%, by weight, of a hollow member 8 made of glass or ceramic powder having an average diameter of about 5 μm to 50 μm. A material that forms an air layer to increase thermal resistance and reduce specific gravity is used. Further, the bottom plate 3 is also made of a material containing a hollow member 8 mainly made of a synthetic resin 7 such as polypropylene that can withstand a rise in temperature during rice cooking and warming, similarly to the outer frame 2. on the other hand,
The coil base 11, which is a separate component from the outer frame 2 and forms the bottom of the pan housing 4, is mainly made of a synthetic resin 7 such as polyethylene terephthalate.
And a material containing the same hollow member 8.

As shown in FIG. 3, the pot 5 has a pot base 13 made of a material having good heat conductivity such as aluminum. A heating element 14 made of a magnetic metal material such as stainless steel is joined to the outer surface of the pot base 13 at the bottom and the lower side. On the inner surface of the pot base 13, a primer coat layer 15 made of PTFE paint or the like is formed. Further, an inner top coat layer 16 made of PFA paint or the like is formed on the inner surface of the primer coat layer 15. This inner top coat layer 16 forms the inner surface of the pot 5. On the other hand, an undercoat layer 17 made of a silicone-based paint or the like is formed on the outer surface of the pot base 13 including the heating element 14. The undercoat layer 17 contains a number of powdery hollow members 19 made of glass or the like having a hollow space 18 therein. Further, on the outer surface of the undercoat layer 17, an outer topcoat layer 20 made of a silicone-based paint or the like is formed. The outer top coat layer 20 forms the outer surface of the pot 5.

A flange 21 extending outward in the horizontal direction is formed on the upper part of the pan 5. The lower surface of the flange 21 is placed on the upper end of the pan storage 4, whereby the pan storage 4
Is configured to accommodate the pan 5 in a suspended state. At this time, a first space 22 having a gap of about 1 to 7 mm is formed between the outer surface of the pan 5 and the inner surfaces of the pan housing wall 6 and the coil base 11.

Reference numeral 26 denotes a pot temperature sensor serving as pot temperature detecting means provided at the center of the bottom of the coil base 11. The pan temperature sensor 26 detects the outer surface temperature of the bottom of the pan 5. Reference numeral 27 denotes a heating coil for electromagnetic induction heating, which serves as a pot heating means serving as a heating means provided on the outer surface of the coil base 11. The heating coil 27 faces the heating element 14 at the bottom of the pot 5 and at the bottom of the side surface thereof, and causes the heating element 14 to generate heat. A heating coil 27 for heating this portion may be provided only on the bottom surface of the pot 5 or in a state facing a plurality of portions on the side surface of the pot 5. A body heat insulating wall 29 is provided outside the pan housing wall 6 with a second space 28 having a predetermined gap interposed therebetween. The body heat insulating wall 29 is formed integrally with the outer frame 2 similarly to the pot housing wall 6. Therefore, the pan housing wall 6 and the body heat insulating wall 29 are made of the same material as the outer frame 2 and have reasonable manufacturability simultaneously formed at the time of injection molding. Is included.

A coil cover 31 is provided outside the coil base 11 with a predetermined gap therebetween. The material of the coil cover 31 is a material mainly composed of a synthetic resin 7 such as polyethylene terephthalate that can withstand a rise in temperature during cooking and keeping the temperature, and includes a hollow member 8 similar to the coil base 11. When the bottom of the coil base 11 is covered with the coil cover 31, the gap at the lower end of the pot housing wall 6 is almost shielded, and a space 28 is formed on each of the outer bottom surface and the outer surface of the pot housing portion 4. Has become. Further, a ferrite member 32 for preventing leakage of magnetic flux from the heating coil 27 is mounted outside the coil cover 31.

A third portion formed between the outside of the body heat insulating wall 29 and the coil cover 31 and the inside of the outer frame 2 and the bottom plate 3.
In the space 36, a heating substrate 37 is provided. This heating board 37
Is a heating board unit 38 which is a control circuit of the heating coil 27.
And a switching element 39 as a heat-generating component. The heating board unit 38 includes an inverter circuit that supplies a predetermined high-frequency current to the heating coil 27, and supplies a predetermined high-frequency current to the heating coil 27. When the high-frequency current is supplied, a magnetic field is generated in the heating coil 27, so that the heating element 14 of the pan 5 is heated by electromagnetic induction heating, and the pan 5 is heated. A radiator plate 40 for cooling the switching element 39 is attached between the switching element 39 for generating a high-frequency current and the heating board 37. A vent 41 is formed in the bottom plate 3 below it, and outside air is introduced from this vent 41,
A cooling fan 42 for blowing air to the heating substrate 37 side is provided. 43 is a code reel provided on the outer bottom of the bottom plate 3. The cord reel 43 accommodates a power supply wire so as to be wound up. Another substrate 44 is provided in the third space 36 above the heating substrate 37. On the substrate 44, a power supply unit 45 and a display operation unit 46 provided with a control circuit and the like face an operation panel 47 corresponding to an operation unit for starting and stopping a heating operation mounted on the front surface of the outer frame 2. Provided.

Reference numeral 51 denotes a lid that directly covers the upper opening of the pot 5. The lid body 51 forms an outer lid 52 which forms an outer shell of the lid body 51, and a portion which is on the lower periphery of the lid body 51 and does not face the upper opening of the pot 5, and the lower end of the outer lid 52 is An outer lid cover 53 fitted to the outer periphery thereof and a lower lid member 54 forming the lower surface of the lid body 51 and facing the upper opening of the pot 5 are generally configured. The outer lid 52 is made of a material including a synthetic resin 7 such as polypropylene capable of withstanding a rise in temperature during rice cooking and warming as in the outer frame 2 and the like, and including a hollow member 8. On the other hand, the lid lower surface member 54 is made of aluminum, stainless steel, or the like. In addition, a concave portion 55 is formed on the lower surface and an annular groove 56 is formed on the upper surface, that is, the rear surface, in the outer peripheral portion of the lid lower surface member 54. These recesses
The groove 55 and the groove 56 are provided to suppress a rise in the temperature of the outer peripheral portion of the lid lower surface member 54. In addition, on the outer surface of the concave portion 55 and the groove 56 in the lid lower surface member 54, there is a rising portion 57 for attaching the lid lower surface member 54 to the outer lid cover 53.

The upper surface of the lid lower member 54, which is also a member forming the inner surface of the lid 51, that is, a surface inside the lid 51, has a lid temperature detecting means for detecting the temperature of the lid lower member 54. In addition to the sensor 61, a lid heater 62 serving as a lid heating means including a cord heater, that is, a cord-shaped electric heater, is arranged in a predetermined pattern. This lid heater 62
An aluminum tape 63 covering almost the entirety from above is fixed to the lid lower surface member 54 by bonding the aluminum tape 63 to the lid lower surface member 54. This aluminum tape 63
Is obtained by adhering a double-sided adhesive tape 65 to an aluminum foil 64. That is, the lid heater 62 is
And an aluminum foil 64.

The lid heating means provided inside the lid 51 is not limited to the lid heater 62 configured as in this embodiment. For example, the lid lower surface member 54 is formed of a magnetic metal material, a heating coil is provided inside the lid body 51, a predetermined high-frequency current is supplied to the heating coil, and the lid lower surface member 54 is heated by electromagnetic induction. There may be.

Above the lid lower member 54, a lid lower heat shield 66 is provided.
Is provided between the lid lower surface member 54 and the lid heater 62 via a space. This heat shield plate 66 on the lower surface of the lid is
As in the case of 52, the main component is a synthetic resin 7 such as polypropylene that can withstand the temperature rise during rice cooking and heat retention, and the hollow member 8
It consists of the material containing. Further, another outer cover heat shield plate 67 is provided inside the outer cover 52, that is, on the lower side.

Between the outer lid cover 53 and the lid lower surface member 54,
A lid packing 71 made of an annular elastic body and having a lower part in close contact with the upper surface of the pot 5 when the lid 51 is closed is provided.
The lid body 51 is pivotally supported on the heat retaining pot main body 1 by a hinge portion 72 provided at a rear portion of the heat retaining pot main body 1. The hinge 72
A clamp button 73 serving as a lid locking portion is provided on the front side of the insulated pot main body 1 on the opposite side of the above, and by locking the front portion of the lid 51 with the clamp button 73,
The lid 51 is locked so as to cover the upper opening of the pot 5.

The upper surface of the outer lid 52 is provided with a concave portion 76 which is depressed toward the pot 5. Also, corresponding to the center of the recess 76,
A hole 77 is provided in the lid lower surface member 54, and a steam cylinder 79 forming a lower portion of the steam port 78 is attached to the hole 77. Then, the space between the bottom back side of the concave portion 76 located around the hole 77 and the back surface of the lid lower surface member 54 is sealed with a vapor port packing 80 made of silicone rubber. The steam port 78 has a steam port cap 81
And a steam port case 82 having the steam cylinder 79 formed therein.
It is detachably mounted from the outside of the opening. The steam port cap 81 is detachably provided in the upper opening of the steam port case 82, and has a plurality of steam discharge holes 83 formed in the upper surface thereof. At the center of the steam port cap 81, a cylindrical wall portion 84 that hangs downward is formed. The lower end of the cylindrical wall portion 84 faces the outer peripheral side of the upper end portion of the steam cylinder 79, and a plurality of steam passages 85 are formed in the upper portion of the side surface of the cylindrical wall portion 84. Further, the upper portion of the cylindrical wall portion 84 includes the cylindrical wall portion.
A pressure regulating valve 86 for closing the upper opening of 84 is attached. In the steam port 78, a space surrounded by the cylinder wall 84 and the pressure regulating valve 86 above the steam cylinder 79 is a first pressure regulating chamber.
The space on the outer peripheral side of the cylinder wall portion 84 and the steam cylinder 79 forms a second pressure regulation chamber 88. Reference numeral 89 denotes an oil return hole formed at the base of the steam cylinder 79. The lid heater 62 is also provided near the steam port 78, and is configured to heat the bottom of the steam port 78 simultaneously with the lid lower surface member 54.

Then, the steam generated in the pot 5 during the rice cooking is discharged to the outside through the steam port 78 of the closed lid 51. In other words, the steam in the pot 5 is first mixed with the water such as the asparagus (starch broth) and the steam in the steam port case 82.
It rises inside 79 and blows out to the first pressure regulating chamber 87 around the upper opening of the steam cylinder 79. Here, the moisture and the steam are separated from each other, and the steam flows from the steam passage 85 to the second surrounding area.
Is discharged to the upper part of the pressure regulating chamber 88, and is further discharged to the outside of the steam port 78 through the steam discharge hole 83 of the steam port cap 81. On the other hand, the moisture separated from the steam falls to the lower part of the second pressure regulating chamber 88. Then, a part of the water collected in the lower part in the second pressure regulation chamber 88 becomes steam by heating and is discharged from the steam discharge hole 83 to the outside. When the rice cooking is completed and the steam is almost completely eliminated, the second pressure regulating chamber 88 is stopped.
The water that has accumulated inside the pot 5 returns to the inside of the pot 5 through the return hole 89, and is collected.

Next, the electrical configuration will be described with reference to FIG. 4. Reference numeral 91 denotes a microcomputer (hereinafter, referred to as a microcomputer), which is not shown, but is not shown in the drawings. In addition to devices and arithmetic devices, timing devices, storage devices such as ROM and RAM,
And an input / output device. Each operation signal from the operation switch 92 provided in the display operation unit 46 and each temperature detection signal from the substrate temperature sensor 93 provided on the pan temperature sensor 26, the lid temperature sensor 61, and the heating substrate 37. Is input to the microcomputer 91, and based on the input, the heating amount as the output of the heating coil 27 and the power cutoff of the heating coil 27 via the IH drive circuit 94 and the high-frequency current generating means 95 constituting the heating board unit 38. Control the time and the power supply of the lid heater 62 via the heater drive circuit 96 and the power supply / disconnection means 97, and further provided on the display operation unit 46 via the display drive circuit 98. The display operation of the display device 99 is configured to be controlled. The microcomputer 91 holds the rice in the pot 5 at a predetermined temperature by heating by the heating coil 27 and controls the lid heater 62 as a control sequence of a program held by the microcomputer 91.
And a temperature maintaining means 101 for maintaining the temperature of the portion of the lid 51 facing the pan 5 and the temperature of the steam port 78 at predetermined temperatures. The operation will be described later in further detail.

Next, the heating control during cooking and keeping the temperature warm will be described with reference to the graph of FIG. In addition,
In the same figure, the solid line graph at the top shows the temperature of the pan temperature sensor 26, and the dotted line graph at the top shows the lid temperature sensor.
61 shows the temperature. The middle graph in the figure shows the timing and output of the power cutoff of the heating coil 27, and the lower graph in the figure shows the timing and output of the power cutoff of the lid heater 62. In the middle and lower graphs in the figure, the hatched portions indicate the energization timing. In the rice cooking process, a cooking process, a boiling heating process, a boiling continuous heating process, a cooking process, and a drying process are sequentially performed. Hereinafter, the control of these steps will be described, but the numerical values and time specifically exemplified vary according to the rice cooking course, the product, and the like.

When rice and water are stored in the pot 5 and rice cooking is started, first, a hot cooking process for promoting water absorption of the rice in the pot 5 is performed. In this hot-cooking process, the output of the induction heating of the pot 5 is relatively low, and the water temperature in the pot 5 is 30 ° C. to 55 ° C.
It is kept at 10 ° C for 10 to 20 minutes. In the subsequent boiling heating process, the heating coil 27 is continuously heated at the maximum heating power of 1300 W until the water in the pot 5 boils. When the pot temperature sensor 26 detects the boiling of the water in the pot 5, the process proceeds to the boiling continuous heating step, the heating output of the heating coil 27 is reduced to 1000 W, and the heating coil 27 is turned on and off by repeating the on / off switching power cycle. The power is turned off and the pot 5 is heated intermittently (pot heating), and the boiling in the pot 5 is continued. Then, when 3 to 7 minutes have passed and the water in the pot 5 has almost run out, the output of the heating coil 27 is set to 1300 W again, and the intermittent heating by repeating the on and off of the heating coil 27 is continued to complete the cooking process. Do. When the temperature of the pot 5 rises to a predetermined temperature, the cooking process ends, and the process shifts to a spotting process. During the steaming, the temperature of the rice in the pan 5 should be between 98 ℃ and 100 ℃
The output of the induction heating of the pot 5 is made relatively low so that the heating is performed intermittently so as to keep it for 10 to 15 minutes.

Then, when a predetermined period of time is completed,
The heat is kept by the heat keeping means 101. In this warming process,
According to the temperature detected by the pot temperature sensor 26, the temperature of the rice in the pot 5 (hereinafter, appropriately referred to as a heat retaining temperature) is 72 ° C. when the temperature is stabilized.
The heating is performed so that the temperature is controlled to 7878 ° C., preferably 73 ° C. to 77 ° C. This thermal insulation heating increases the heating output of the heating coil 27 by 50.
The power is reduced to 0 W, and power is cut off through the heating coil 27 by repeating a power-off cycle of 0.35 seconds on and 5 seconds off.
For example, when the temperature of rice is kept at 74 ° C., if the temperature of the pot 5 is 74 ° C. or higher, the on of the aforementioned 0.35 seconds is omitted, and the pot 5
If the temperature is less than 74 ° C., the above-mentioned ON for 0.35 seconds is executed to keep the temperature of the pot 5 at 74 ° C.

During cooking rice, the lower surface of the lid 51 is heated by the lid heater 62. In other words, after the boiling heating process is completed, the lid heater is repeatedly turned on and off by repeating the power cut cycle.
The power is cut off through 62, and the lower surface of the lid 51 is intermittently heated. When the uneven process is reached, the temperature of the lower surface of the lid 51 is 100 ° C or more,
Heating is performed by the lid heater 62 based on the temperature detected by the lid temperature sensor 61 so that the temperature becomes 105 ° C. to 110 ° C. Thereby, dew condensation hardly remains on the lower surface of the lid 51 immediately after cooking rice. In addition, during the heat retention, until the heat retention temperature is stabilized, the lid heater 62 is turned off by repeating a cut-off power cycle such as, for example, 10 seconds on and 30 seconds off, and the lower surface of the lid 51 is kept at a predetermined level. When the temperature is stabilized intermittently and the heat retention temperature is stabilized, the lower surface of the lid 51 is heated so as to be slightly higher than the temperature of the rice, and dew condensation on the lower surface of the lid 51 is suppressed. At this time, the temperature of the lower surface of the lid 51 is + 1 ° C. to + 5 ° C., 0 ° C. to + 5 ° C.
The temperature may be temporarily the same as or lower than the temperature of the rice, such as 4 ° C. or −1 ° C. to + 3 ° C., but it is higher than the temperature of the rice on average.

As described above, the bottom of the steam port 78 is heated simultaneously with the cover lower surface member 54 by the cover heater 62 as one heat source, and the temperature inside the steam port 78 is reduced. The control temperature of heating by the lid heater 62 is set so as to be 50 ° C. or higher, preferably 55 ° C. or higher. Incidentally, it is preferable that the lid lower member 54 and the steam port 78 can be simultaneously heated by the common lid heater 62 as in this embodiment, but the heating of the lid lower member 54 results in the temperature of the steam port 78 being lowered. The configuration for heating the steam port 78 is not limited as long as it rises sufficiently. Also, as described above, the lid lower surface member 54 may be configured to be heated by electromagnetic induction.

Here, test results regarding the relationship between the heat retention temperature and the heat retention state centering on the generation of putrefaction odor will be described. First, when the heat retention temperature is set to 70 ° C. to 71 ° C., and the heat retention time is longer than usual for about 48 hours, there is a case where a rotten odor is generated although there is a variation depending on each body of the heat retention pot. In addition, the heat retention is temporarily stopped to make the rice cold, or the heating of the lid 51 is forcibly stopped, so that the temperature of the steam port 78 is low and a large amount of dew is condensed on the lower surface of the lid 51. By keeping it warm for about an hour, the rice is intentionally putrefied, discarded and put aside on the contaminated rice cooker and cooked again in a contaminated insulated pot.This time, if it is normally kept at 70-71 ° C, it takes 12 hours. In 24 hours, putrefaction odor was sometimes generated. In addition, when the heat retention temperature was set to 72 ° C to 73 ° C, it was confirmed in the same manner that when the heat was kept for a long time of 48 hours, there was almost no rotting aircraft, but when the heat was kept in a heat tank that was intentionally contaminated, In some cases, it decayed due to variations among aircraft.
In addition, when the heat retention temperature was set to 74 ° C to 75 ° C, it was confirmed in the same manner. There was no corruption problem on the fuselage. For example, it is considered that the rot is generated by keeping the temperature for a long time because the outside air enters the pot 5 through the steam port 78, so that the rot germs in the air may cause the rice to rot. However, even if the spoilage bacteria enter, if the temperature of the rice is sufficiently high, it is considered that the proliferation of spoilage bacteria can be suppressed. From this fact, it is expected that the rot can be suppressed even if the lid 51 is frequently opened and closed in practical use and a large amount of rot bacteria in the air enters.

In addition, the heat retention temperature is 72 ° C. to 73 ° C. to 74 ° C.
Even when the temperature was set to 75 ° C., when the internal temperature of the steam port 78 was set to 45 ° C., the odor of putrefaction was generated in most of the airframes by keeping the temperature for 48 hours. On the other hand, when the internal temperature of the steam port 78 was set to 50 ° C., the odor of putrefaction disappeared in most of the airframes, and no problem occurred at 55 ° C. From this, when the internal temperature of the steam port 78 becomes equal to or lower than the temperature at which the rotten bacteria can grow, the spoilage bacteria propagated in the steam port 78 spread over the rice in the pot 5 and spoils quickly. It can be seen that raising the temperature to 50 ° C. or more is an important rot prevention measure.

An inner lid is detachably provided below the lid, a gap between the lower surface of the lid and a peripheral portion of the inner lid is used as a steam passage, and a vapor port of the lid is covered by the inner lid from below. In the insulated kettle having a structure, the inner lid serves as a shield plate to prevent the transmission of putrefactive bacteria from the steam port to the rice in the pot, so that the temperature of the steam port does not need to be considered much. On the other hand, in the case of the structure in which the steam port 78 of the lid 51 directly faces the upper surface of the rice in the pot 5 as in the present embodiment, it is not possible to maintain the temperature in the steam port 78 to a certain high temperature. Required.

As described above, by keeping the heat retaining temperature relatively high at 72 ° C. to 78 ° C. and maintaining the temperature in the steam port 78 at a high temperature of 50 ° C. or more, it is possible to surely suppress the proliferation of spoilage bacteria. It is possible to keep the heat for a long time, or to resume the heat after temporarily interrupting the heat retention, or when the rot bacteria in the air invades the pot 5 by opening and closing the lid 51 frequently. However, the proliferation of putrefactive bacteria can be suppressed, and the generation of putrefaction odor can be prevented. In addition, the upper limit of the heat retention temperature of rice of 78 ℃,
This is set in consideration of suppression of the heat retention odor that progresses due to the long high-temperature time, as in the conventional concept.

Further, in the insulated pot having a configuration in which the pot 5 is heated by electromagnetic induction heating as in the present embodiment, the temperature of the inner side surface of the pot 5 above the rice is naturally liable to decrease. By raising the temperature, the temperature of the part without rice on the inner surface of the pot 5 becomes higher than before, and
Since the temperature of the rice rises, the temperature of the lower surface of the lid 51 inevitably rises in synchronization with the rice, so that the temperature difference between the rice and the lower surface of the lid 51 is lower than the temperature of the rice. Can be minimized in a high temperature range. Therefore, the temperature difference between the inner surface of the portion of the pot 5 where there is no rice and the lower surface of the lid 51 is reduced within a temperature range in which the proliferation of putrefactive bacteria can be suppressed.
The amount of dew condensed on the inner surface can be reduced. Thereby, the stickiness of the rice around the pot 5 can be reduced.

As described above, good heat insulation can be performed, and a heat insulation pot with an improved heat insulation state can be provided.

Further, if the lower surface of the lid 51 and the steam port 78 are commonly heated by the lid heater 62 as one lid heating means as in the above-mentioned embodiment, the cooling of the steam port 78 can be prevented. The effect can be realized with a simple structure.

FIG. 6 is a top view of a lower cover member 54 of a lid 51 showing another embodiment of the heat retaining pot of the present invention. The insulated pot of this embodiment also serves as a rice cooker, and has almost the same configuration as the insulated pot of the previous embodiment. The description thereof will be omitted, and reference numerals in the drawings of the above embodiment will be referred to as appropriate. In this embodiment, the lid lower surface member 54, which is a member forming the inner surface of the lid 51, is made of an austenitic stainless steel plate having a thickness of 0.3 mm to 0.5 mm. A lid heater 62 serving as a lid heating means composed of a code heater is arranged in a predetermined pattern on the upper surface of the lid lower surface member 54, that is, the surface inside the lid body 51. The lid heater 62 is adhered to the lid lower surface member 54 by an aluminum tape 63 composed of an aluminum foil 64 and a double-sided adhesive tape 65, as in the previous embodiment.
In FIG. 6, the aluminum tape 63 is hatched, though not in cross section, for easy understanding. As shown in FIG. 6, the aluminum tape 63 is made as large as possible, and has a size substantially equal to that of the lid lower surface member 54. That is, aluminum tape 63
Extends over the entire upper surface of the lid lower surface member 54 except for a rising portion 57 and a steam port 78 portion on the outer peripheral portion of the lid lower surface member 54, and also covers a portion of the lid lower surface member 54 where the lid heater 62 is not disposed. Glued.

On the other hand, FIG. 7 is a top view of a lower cover member 54 of a lid body 51 of a conventional warming pot such as a rice cooker. As described above, in the conventional insulated pot, the aluminum tape 63 for attaching the lid heater 62 composed of a cord heater to the lid lower surface member 54 (not shown in cross section for simplicity) is provided with the lid heater. This is slightly larger than the arrangement range of 62, and the area is only about half of the lid lower surface member 54.

As in the above-described embodiment, in the heat retaining pot without the removable inner lid for easy maintenance, the lid lower surface member 54 of the lid 51 that covers the pot 5 from above does not rust and has a high gloss. There are times when stainless steel with beautiful appearance is used. On the other hand, stainless steel has poor heat conductivity, which is a drawback in heating by the lid heater 62 for preventing dew on the lower surface of the lid 51 immediately after the completion of rice cooking or while keeping the temperature. That is, since aluminum has good thermal conductivity, heat conduction through the aluminum tape 63 can be expected.However, if the aluminum tape 63 is small as in a conventional insulated pot, the lid heater serving as a heating source in the lid lower surface member 54 Only the portion having the heater 62 is heated, and the portion without the lid heater 62 is exposed. When dew condensation occurs in this way, when the lid 51 is opened, the dew attached thereto flows down to the outer frame 2 and the like, and stains the outer frame 2 and the like.
Cleaning also takes time.

When the aluminum tape 63 is small,
Since the contact area between the aluminum tape 63 and the lid lower surface member 54 is small, when the aluminum tape 63 is peeled off from the lid lower surface member 54, the lid heater 62 is easily separated from the lid lower surface member 54. When the lid heater 62 separates from the lid lower surface member 54 in this manner, the lid 51 becomes insufficiently heated, and dew increases.

On the other hand, in the heat retaining pot of the present embodiment, the aluminum tape 63 for bonding the lid heater 62 composed of the cord heater to the lid lower surface member 54, which is the object to be heated, is made as large as possible. Since the size of the lower surface member 54 is substantially the same as that of the lower surface member 54, the heat generated by the lid heater 62 is conducted using the aluminum tape 63 having good thermal conductivity as a medium, and the heat is applied to a portion of the stainless steel lower surface member 54 where the lid heater 62 is not provided. To communicate well. That is, when the lid heater 62 generates heat, first, the lid lower surface member 54 is heated in a portion where the lid heater 62 is in contact, and heat is transmitted to a portion where the lid heater 62 is not in contact by heat conduction. If the thermal conductivity of the lid lower surface member 54 is poor as in the case, heat is hardly transmitted to the entire lid lower surface member 54. However, since the aluminum tape 63 for bonding the lid lower surface member 54 and the lid heater 62 has excellent thermal conductivity, heat is transmitted through the aluminum tape 63 having almost the same size as the lid lower surface member 54, so that the lid The entire lower surface member 54 is substantially uniformly heated, and uneven heating is reduced.

As described above, according to the configuration of the above embodiment, even the lid lower surface member 54 made of stainless steel or the like which is clean in appearance but has poor heat conductivity can be substantially uniformly heated, so that it can be heated during rice cooking and heat retention. Can be prevented from dewing on the lower surface of the lid 51. Therefore, the lid 51, the outer frame 2 and the like do not need to be contaminated with dew, and the maintenance is easy.

Also, the lid lower surface member 54 and the aluminum tape
The aluminum tape 63 is hardly peeled off from the lid lower surface member 54 because the bonding area with the lid 63 is large, and even if the aluminum tape 63 is partially peeled off, the lid heater 62 composed of a code heater is formed.
It is less likely that the lid will separate from the lid lower surface member 54.
Therefore, the risk of insufficient heating due to the lid heater 62 being separated from the lid lower surface member 54 is reduced, and the lid 51 can be stably and efficiently heated over a long period of time.

Here, experimental results regarding the heating action of the lid 51 of the present embodiment shown in FIG. 6 and the lid 51 of the conventional example shown in FIG. 7 will be described with reference to FIGS. 8 and 9. FIG. 8 shows this embodiment, and FIG. 9 shows a conventional example. In these figures, the graph of A indicated by a solid line is the temperature of the central portion of the lid lower surface member 54 indicated by the symbol A in FIGS. 6 and 7, and the graph of B indicated by the broken line is indicated by the symbol B in FIGS. The temperature in the vicinity of the steam port 78 of the lid lower surface member 54 shown in the graph, the dashed line C represents the rice temperature, and the dashed line D represents the temperature of the side surface of the pot 5.
Also, the time range of these graphs is before and after cooking rice,
That is, it is from the time of spotting to the initial time of keeping the temperature.

In the conventional insulated pot, the temperature at the center of the lid lower surface member 54 has a maximum value of 172 ° C. and is generally high, while the temperature near the steam port 78 of the lid lower surface member 54 is The maximum value is about 100 ° C, which is lower overall. On the other hand, in the insulated pot of the present embodiment, the maximum temperature of the central part of the lid lower surface member 54 is 151 ° C., which is lower than the conventional example (172 ° C.). The maximum value of the temperature near the steam port 78 of the lower surface member 54 is 105 ° C., which is higher than the conventional example (101 ° C.) as a whole. That is, it is apparent that the temperature of each part of the lid lower surface member 54 is more uniform in the heat retaining pot of the present embodiment than in the conventional heat retaining pot.

When the amount of dew was measured one hour after the heat retention, the frame of the heat retainer main body 1 was 0.39 m in the conventional heat retainer.
l, while the lid lower member 54 was 0.04 ml and the side of the pan 5 was 0.88 ml, in the insulated pot of the present embodiment, the frame of the insulated pot main body 1 was 0.00 ml, and the lid lower member 54 was 0.00 ml, side of pan 5 is 0.
55 ml. That is, it is apparent that the insulated pot of the present embodiment has much less dew adhesion than the insulated pot of the conventional example.

Note that the present invention is not limited to the above-described embodiment, and various modifications can be made. For example,
The effect of enlarging the aluminum tape 63 for bonding the lid lower surface member 54 and the lid heater 62 is effective when the lid lower surface member 54 is made of a material having poor heat conductivity such as stainless steel as in the above embodiment. Although it is particularly remarkable, even when aluminum or the like having good heat conductivity is used as the material of the lid lower surface member 54, by forming the aluminum tape 63 to be substantially the same size as the lid lower surface member 54, Can be more uniformly heated, energy can be saved by preventing overheating. Further, even when the arrangement area of the lid heater 62 for heating the lid lower surface member 54 is small, or in a place where it is difficult to provide the lid heater 62 due to its structure, the heating can be performed via the aluminum tape 63.

[0054]

According to the invention, the temperature of the rice in the pot is kept at 72 ° C. to 78 ° C. when the temperature of the rice during the heat retention by the heat retaining means is stabilized. Since the temperature of the surface facing the pot is kept slightly higher than the temperature of the rice, it can be used for long periods of time, for re-heating after temporarily stopping the heating, or when opening and closing the lid frequently. The generation of putrefaction odor can be prevented, the dew condensation around the pot can be suppressed, and the heat retention state can be improved.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the temperature of the inside of the steam port is maintained at 50 ° C. or more, so that the putrefactive bacteria entering the steam port from the outside can be obtained. Can be suppressed from spreading to the inside of the pot, and the generation of putrefaction odor can be more reliably prevented.

According to the insulated pot of the third aspect of the present invention, in addition to the effects of the first or second aspect, the lid heating means is provided with a surface facing the pot of the lid and the steam port by one heat source. Are simultaneously heated, so that it is possible to prevent the steam port from cooling down with a simple structure.

According to the warming pot of the fourth aspect of the present invention, the temperature of the rice in the pot is maintained at 72 ° C. to 78 ° C. when the heat is kept by the heat retaining means, and the temperature of the portion of the lid facing the pot is controlled by the temperature of the rice. Since the temperature is kept slightly higher than the temperature, it is possible to prevent the generation of putrefaction odor even when keeping warm for a long time, reheating after temporarily suspending warming, or opening and closing the lid frequently. Since the heating means is of the electromagnetic induction heating type, the temperature of the upper portion of the pan is liable to be lowered, but the dew condensation around the inside of the pan can be surely suppressed and the heat retaining state can be improved.

According to the fifth aspect of the present invention, in addition to the effects of any one of the first to fourth aspects, in addition to the effects of the first to fourth aspects, the lid heating means has good thermal conductivity to the member forming the inner surface of the lid. The tape made of a member having good thermal conductivity is made approximately the same size as the member forming the inner surface of the lid body, while the cord heater made of a cord heater adhered by a tape made of a member is used. The heat generated by the cord heater is transmitted to almost all of the members forming the inner surface of the lid via a tape made of good aluminum or the like, so that dew condensation on the members can be suppressed. At the same time, it is possible to prevent insufficient heating due to peeling of the aluminum tape and separation of the cord heater from the member forming the inner surface of the lid.

In particular, as in the insulated pot of the invention of claim 6,
When the member forming the inner surface of the lid is made of stainless steel having poor heat conductivity, the entirety of the inner surface of the lid, including the portion without the cord heater, can be substantially uniformly heated by the configuration of the invention of claim 5.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing an embodiment of a heat retaining pot of the present invention.

FIG. 2 is an enlarged cross-sectional view of an outer frame, a bottom plate, a coil base, a coil cover, an outer lid, a heat shield plate on a lower surface of the lid, and the like.

FIG. 3 is an enlarged sectional view of the pot.

FIG. 4 is a block diagram showing an electrical configuration of the same.

FIG. 5 is a graph showing the timing of heating and the change over time in temperature.

FIG. 6 is a top view of a lower cover member showing another embodiment of the heat retaining pot of the present invention.

FIG. 7 is a top view of a conventional lid lower surface member.

FIG. 8 is a graph showing a temperature change of each part of the heat retaining pot of the embodiment shown in FIG. 6;

FIG. 9 is a graph showing a temperature change of each part of a conventional heat retaining pot.

[Explanation of symbols]

 5 Pan 27 Heating coil (pan heating means, heating means) 51 Lid 54 Lower lid member (member forming inner surface of lid) 62 Lid heater (lid heating means) 63 Aluminum tape 78 Steam port 101 Heat retaining means

Claims (6)

[Claims] 1. A pan, a lid covering the pan, a pan heating means for heating the pan, a lid heating means for heating the lid and a steam port provided on the lid, Means for maintaining the rice in the pan at a predetermined temperature by means and a means for maintaining the temperature of the lid and the steam port at a predetermined temperature by means of the lid heating means. When stable, the temperature of the rice in the pan is maintained at 72 ° C. to 78 ° C., and the temperature of the surface of the lid facing the pan is maintained slightly higher than the temperature of the rice. Insulated heating pot. 2. The heat insulation kettle according to claim 1, wherein said heat insulation means is configured to maintain the temperature inside said steam port at 50 ° C. or higher. 3. The thermal insulation according to claim 1, wherein the lid heating means is configured to simultaneously heat the surface of the lid facing the pot and the steam port by one heat source. Kettle. 4. A heating means for electromagnetically heating a bottom portion and a lower side portion of the pan to maintain the temperature of rice in the pan at a predetermined temperature, and the lid is provided by a lid heating means provided inside a lid for covering the pan. A heat retaining means for maintaining the temperature of the portion of the body facing the pot at a predetermined temperature is provided, and the temperature of the rice in the pan is kept at 72 ° C to 78 ° C during the heat retention by the heat retaining means, and the lid is placed in the pot. A warming pot characterized in that the temperature of the facing part is maintained slightly higher than the temperature of the rice. 5. The lid heating means comprises a cord heater adhered to a member forming an inner surface of the lid by a tape made of a member having good heat conductivity, and a tape made of the member having a good heat conductivity is provided. The heat insulation pot according to any one of claims 1 to 4, wherein a size of the lid is approximately the same as a member forming an inner surface of the lid. 6. The heat retaining pot according to claim 5, wherein a member forming an inner surface of the lid is made of stainless steel.