JPH04126109A - Heating cooker - Google Patents

Abstract

PURPOSE:To obtain the cooker which can cook the same delicious 'rice' as cooking by a cooking stove, and is excellent in the cooking environment, and to prevent the rice from being boiled down and being burned even in the case of heating cooking by providing a heating part which uses power as a heating source on one part of an outer rice-cooking pot, and sealing in a thermal medium between the outer rice- cooking pot and an inner rice-cooking pot, and heating the inner rice-cooking pot through the thermal medium. CONSTITUTION:An inner rice-cooking pot 1 and an outer rice-cooking pot 2 are integrated. The integration is executed by welding, etc. In the outer rice-cooking pot 2, a low frequency electromagnetic induction heating part 3 is provided. As for the electromagnetic induction heating part 3, it is desirable to provide it on the lower part of the outer rice-cooking pot 2, because the inner rice-cooking pot 1 is heated through a thermal medium. Between the inner rice-cooking pot 1 and the outer rice-cooking pot 2, the thermal medium 4 is filled in. As for the thermal medium, silicone oil, mineral oil, edible oil, etc., can be used, but it is desirable to use edible oil such as 'tempura' (fried food) oil, etc., by reason of sanitation and safety. In the case 'tempura' oil is used, it is desirable to hold a vacuum between the inner rice-cooking pot 1 and the outer rice-cooking pot 2, and to fill its part with 'tempura' oil in order to prevent oxidation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates primarily to a commercial heating cooker using electric power such as low frequency electromagnetic induction heating as a heat source.

[Prior Art] In recent years, there has been a strong demand for the development of electric heating type heating cookers as heat sources for large-capacity commercial automatic rice cookers, miso soup pots, soup kettles, simmering steels, and the like. The following is an explanation using a large-capacity automatic rice cooker for commercial use as an example.

Rice (rice) has been an important staple food for Japanese people since ancient times, and eating delicious rice is always in demand. In the past, to make delicious rice, people used a furnace and a pot, and accumulated a lot of know-how about adjusting the amount of water and heat. The secret to cooking rice is hidden in the proverb, ``It's slow at first, it's crackling in the middle, and even if the baby cries, don't take the lid off.''

By the way, large-capacity commercial rice cookers such as To-daki (approximately 15 kg), Ni-to-daki, and even Shito-daki (1 bag of rice) are used by bento companies such as ekiben, food service providers, restaurants, sushi restaurants, and the Self-Defense Forces. It is widely used by various organizations such as Due to changes in fuel conditions, the heat source for conventional commercial rice cookers used by these businesses is mostly combustion gas or high-pressure steam, rather than burning wood. Also, home rice cookers are electric resistance heaters (so-called electric kettles).
, a hot air type using an electric heater, or a combustion gas heating type.

[Problems to be Solved by the Invention] However, in the case of large-capacity commercial rice cookers, the combustion gas heating type cannot avoid the problem of deterioration of the working environment due to exhaust gas and waste heat, resulting in poor working conditions. Due to the environment, there is a problem that cooking workers do not last long. The situation is especially severe in the summer. Furthermore, with the combustion gas heating method, it is not easy to control the amount of gas or air mixture, and accurate temperature control is difficult, which often results in failure in cooking.

Also, if you use combustion gas as a heat source for a miso soup pot, soup kettle, simmering pot, etc., it may boil over,
There is also the issue of burning.

Next, heating methods using high-pressure steam require high-pressure boiler equipment, resulting in high equipment costs and difficulty in accurately controlling temperature.

Further, the conventional one-type electric resistance heater has the problem of partial heating and local heating, and is therefore unsuitable as a heat source for a large-capacity commercial heating cooker.

In order to solve the above-mentioned problems of the prior art, the present invention uses heating by electricity supply as a heating source and indirect heating using a heat medium. To provide a heating cooker which has an excellent cooking environment, prevents boiling or burning when cooking miso soup, soup, simmered dishes, etc., and does not require very high equipment cost. .

[Means for Solving the Problems] In order to achieve the above object, the heating cooker of the present invention is a heating cooker in which an outer pot and an inner pot are integrated, and the cooking material is heated in the inner pot, A heating part that uses electric power as a heating source is provided in any part of the outer pot, a heating medium is sealed between the outer pot and the inner pot, and means is provided for heating the inner pot via the heating medium. It is characterized by:

In the above configuration, the heating section using electric power may be a resistance heater or the like, but is preferably a low frequency electromagnetic induction heating section.

In addition, in the above configuration, an AC power supply with a frequency of approximately less than 1°000Hz can be used to supply power to the coil part of the low frequency electromagnetic induction heating part, but a commercial wave number (50
It is preferable to use an alternating current power source (Hz or 60H2).

Further, in the above configuration, silicone oil or the like may be used as the heat medium, but it is preferable to use edible oil.

Further, in the above structure, it is preferable for operation that a support shaft is provided on the side of the outer pot or the inner pot, and that automatic reversing means is provided via the support shaft.

Moreover, in the said structure, it can be used as a commercial automatic rice cooker as a heating cooker. Of course, it can also be used as a variety of large-capacity heating cookers, such as a pot for boiling miso soup, a soup kettle, and a pot for stews.

Furthermore, in the above configuration, the temperature of the rice in the inner pot is 62°C.
There is a pre-cooking area where the temperature of the rice in the inner pot exceeds 62°C and is maintained at a temperature close to the boiling point of water for at least 20 minutes, and a state where the heating of the heat medium is stopped. It is preferable to provide a control means consisting of a steaming area for holding.

[Function] According to the above configuration, a heat medium is sealed in the outer pot, the heat medium is heated using electric power, and cooking materials such as rice are heated in the inner pot, so a large amount of heat can be used in a short period of time. It can be moved over time, has excellent temperature control, and can raise the temperature without local heating.

As a result, there is less heat radiation and exhaust heat, and the cooking environment can be improved. Furthermore, since the outer pot and the inner pot are integrated, the heating section and the heating medium are enclosed, making it possible to provide a safe device.

Further, according to a preferred configuration of the present invention in which a low frequency electromagnetic induction heating section is provided in any part of the outer pot, a large amount of heat can be efficiently generated in a short time.

Further, according to the preferred configuration of the present invention in which power is supplied to the coil section of the low frequency electromagnetic induction heating section by a commercial frequency AC power source (50 Hz or 60 Hz), the cost of the device can be reduced and the durability can be improved. It can be an excellent device. This is because components using semiconductors such as inverters such as high-frequency current generators are not used.

Further, according to a preferable configuration of the present invention in which the heat medium is edible oil, it is possible to provide an apparatus with excellent hygiene and safety.

Further, according to a preferable configuration of the present invention, in which a support shaft is provided on the side of the outer pot or the inner pot, and an automatic reversing means is provided via the support shaft, the entire pot can be automatically reversed. For example, you can easily take out cooked rice, wash it, etc.

In addition, according to the configuration of the present invention in which the heating cooker is a commercial automatic rice cooker, it is the most difficult commercial rice cooker to use among various large-capacity heating cookers such as miso soup pots, soup kettles, and stew pots. Automatic temperature control can be performed.

Furthermore, there is a pre-cooking area where the temperature of the rice in the inner pot is maintained at 62℃ or less for 10 minutes or more, and a pre-cooking area where the temperature of the rice in the inner pot is maintained at a temperature of over 62℃ and around the boiling point of water for 20 minutes or more. According to a preferred configuration of the present invention, which includes a control means consisting of a steaming area and a steaming area that holds the heat medium in a state in which heating is stopped, it is possible to automatically control the temperature of the pot, and to maintain constant cooking at all times. You can get high quality rice.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show a heating cooker according to an embodiment of the present invention. That is, FIG. 1 is a front view of an automatic rice cooker according to an embodiment of the present invention, and FIG. 2 is a side view of the same.

In Figures 1 and 2, 1 is an inner pot for cooking rice, 2 is an outer pot containing a heating medium and equipped with an electromagnetic induction heater, 3 is a low frequency electromagnetic induction heating section, 4 is a heating medium, and 5 .5' is the support shaft fixed to the side of the outer pot 2, 6.7 is the machine base, 8.8''
1 is a bearing box that rotatably supports the support shafts 5, 5- on the machine base 6.7, 9 is a casing part that covers the lower part of the outer hook 2, 10 is an arm fixing part for fixing the arm 22, 11 is a pipe for introducing the electric wire 12 for supplying electric power, 13 is a part of the machine base anchor, 14 is a heat medium supply part (which may also serve as a safety valve), 15 is a lid part, 17-
19 is a gear.

The operation of the automatic rice cooker configured as above will be explained below.

First, the inner pot 1 and the outer pot 2 are integrated. -Integration can be done by welding or the like. The outer pot 2 is provided with a low frequency electromagnetic induction heating section 3.

Since the electromagnetic induction heating section 3 heats the inner pot 1 via a heat medium, it is preferably provided at the lower part of the outer pot 2.

A heat medium 4 is sealed between the inner pot 1 and the outer pot 2.

The heat medium 4 may be enclosed by, for example, introducing the heat medium from the heat medium supply unit 14 and reducing the pressure of the gas portion with a vacuum pump.
A method can be adopted in which the heating medium is heated to a higher temperature than the temperature normally used, and then the heating medium is flooded and sealed. Although any heat medium such as silicone oil, mineral oil, or edible oil can be used, it is preferable to use edible oil such as tempura oil for hygiene and safety reasons. When using tempura oil, it is preferable to maintain a vacuum between the inner pot 1 and the outer pot 2 or to fill it with tempura oil in order to prevent oxidation. Alternatively, antioxidants may be added.

In the example shown in FIGS. 1 and 2, the number of electromagnetic induction heating sections 3 is three, but this is an example using a three-phase AC power source. In addition, single-phase AC power can also be used. A detailed explanation of the electromagnetic induction heating section 3 and the principle of heat generation will be described later.

Note that another hole (which may be in the shape of a thin pipe) as shown in the electromagnetic induction heating section 3 may be provided to allow cooling fluid such as air or water to flow therethrough. This is for rapid cooling when rapid cooling is required. As another rapid cooling method, it is also possible to provide an external tank and drain the heated oil, or add cooling oil. In such a case, it is preferable to use an inert gas such as nitrogen gas to prevent oxidation of the oil.

In this embodiment, the inner pot 1 is shown as having a shallow bottom shape. This is because the contact area with the heat medium 4 is increased to improve heat transfer efficiency. However, the inner pot 1 does not necessarily have a shallow bottom shape. It is not limited to the temperature difference (△T
), or for miso soup or soup, etc.
Each can be shaped to suit its purpose.

In addition, the inner volume of the inner pot 1 in this embodiment is 5 sho (approximately 7.5 sho).
Kg) or more is preferable, and it is also possible to cook in a large capacity of -Toto (approximately 15 kg) to Shito (1 bale) or more.

Next, the automatic reversing mechanism of the automatic rice cooker of the above embodiment will be explained. Figure 3 shows the steady position (solid line) and the inverted position (2
(dot-dashed line). 16 is a motor, 2
0 is a screw shaft, 21 is a screw holder, 22 is an arm, and other parts common to FIGS. 1 and 2 are given the same numbers.

The operation of the automatic reversing mechanism configured as above will be explained below.

When loading washed rice and water and when cooking rice, the screw holder 21 is located at the left end of the screw shaft 20 so that the casing portion is at position 9 (normal position). When taking out the rice after cooking or cleaning the inside, press a switch (not shown) to rotate the motor 16.
The screw holder 21 is connected to the screw shaft 20 via the gears 17 to 19.
Move it to the right edge. As a result, the casing part is 9′
Rotate to the position (inverted position).

Next, the low frequency electromagnetic induction heating section 3 will be explained using FIGS. 4 to 7. Fig. 4 is a perspective view showing a model of the low-frequency electromagnetic induction heating section 3, Fig. 5 is a cross-sectional view of a heating pipe, Fig. 6 is an example wiring diagram that can be used, and Fig. 7 is a diagram explaining the principle of heat generation. .

In Figures 4 and 5, 31 is an iron core (silicon steel plate or amorphous alloy) for flowing magnetic flux, 32 is an induction coil, and 33
34 is a metal heating pipe, 34 is a copper pipe, 34 is a stainless steel pipe, 36 is a flow of magnetic flux, and 37 is a flow of current.

The operation of the low frequency electromagnetic induction heating section 3 configured as described above will be explained.

When power is supplied to the induction coil 32 from an AC power source with a commercial frequency such as 50 Hz or 60 Hz, magnetic flux is generated in the iron core 31 and flows as a magnetic flux flow 36. Then, a current flow 37 is generated in the metal heating pipe 33. As a result, the metal heating pipe 33 generates heat due to Joule heat.

The principle of this heat generation will be explained using FIG. 7. Figure 7 (A)
is a diagram showing the principle of a transformer. In other words, the coil is 10
100V, 10A AC (50Hz
When a current of 100 V or 60 Hz is applied to the secondary side of the coil wound 100 times, theoretically an alternating current of 100 V and IOA (
50Hz or 60Hz) flows in the opposite direction as an additional current. Next, as shown in Figure 7 (B), if the secondary coil is wound once and an alternating current is similarly passed through the primary side, 2
On the next side, an induced current of IV and 100 OA flows in the opposite direction. In other words, a low voltage, large current short-circuit transformer can be achieved.

The low frequency electromagnetic induction heating section 3 includes an induction coil on the primary side, and 2
A metal pipe is placed on the next side, and the principle of the low-voltage, high-current short-circuit transformer described above is applied. The metal pipe on the secondary side may be made of any metal as long as it has conductivity. For example, it is made of copper or steel. 7th
As shown in Figure (B), the current flowing through a metal pipe (for example, a copper pipe) is large, so it is extremely effective for heating. That is, when a large alternating current flows, Joule heat is generated due to short circuit current, and this is considered to be effective in generating heat. In this sense, voltage is not effective for heating.

Therefore, in the present invention, it is significant that a large current that is truly effective for heating is extracted from the electric power. In addition, although an extremely low voltage flows through the copper pipe on the secondary side, this voltage is low enough to cause an electric shock even if a human body comes into contact with it, so it is extremely safe. In addition, according to the principles of the present invention, the heating area is necessarily large. This is because the metal pipe is placed outside the coil. As a result, a synergistic effect can be achieved in that the heating area can be increased and a large amount of power can be supplied.

Next, as the connection method of the low frequency electromagnetic induction heating section 3, for example, the method shown as an example in FIG. 6 can be adopted.

Figures 6(A) and 6(B) are example wiring diagrams for single-phase power supply,
FIGS. 6(C) to 6(E) are example wiring diagrams in the case of a three-phase power supply. Various other wiring methods can also be adopted.

Experimental Example 1 Next, a rice cooking experimental example using the automatic rice cooker of this embodiment shown in FIGS. 1 to 3 will be described.

First, in order to figure out how to control the temperature, we had a master who cooks rice using a very small number of ovens conduct an experiment, and actually measured the temperature inside the pot and the oven. . As a result, a temperature curve as shown in FIG. 8 could be obtained. What can be seen from Figure 8 is that the temperature inside the oven in the pre-cooking area is below 400°C, and the temperature inside the pot is maintained at below 62°C for about 10 minutes. This is to create sufficient convection in the rice below the gelatinization temperature (approximately 62°C) to equalize the temperature and prevent the formation of so-called cores. This is what ``Hajime Choro Choro'' means. Next, in the cooking area (first, turn up the heat all at once and raise the temperature to about 600 degrees Celsius (“middle flop”)), keep the temperature inside the pot at the boiling point of water, and then pull the firewood. .

After 30 minutes, burn a cedar leaf to create a steaming area.

From the above experimental example, when 36 A' of rice is cooked using 41.4 A' of water, an ideal temperature curve in the pot as shown in FIG. 9 could be derived. In other words, the temperature of the rice in the inner pot is 62
A pre-cooking region in which the temperature of the rice in the inner pot exceeds 62°C and is maintained at a temperature close to the boiling point of water for 20 minutes or more, and a state in which heating of the heating medium is stopped. It is to provide a steaming area that is held in a vacuum.

In order to control the temperature of the heat medium (oil temperature) in the actual device, we control the temperature at the bottom of the inner pot (a sensor is inserted into a slightly recessed part from the outside of the inner pot using compression fitting), the temperature of the steam A temperature control flowchart as shown in FIGS. 10(A) to 10(C) was created by taking temperature and various control times as elements.

Figure 10 (A) is a flow chart of the normal rice cooking process of an automatic rice cooker, Figure 10 (B) is a flow chart for preventing oil temperature heating, and Figure 10 (C) is a flow chart for preventing dry cooking. It is a diagram. You can also manually heat it separately, for example if you want to keep miso soup or soup warm.
It is also possible to maintain the oil temperature at around 80°C.

Experimental Example 2 Using the automatic rice cooker shown in Figs. 1 to 3, rice was actually cooked using the flow chart (microcomputer control) shown in Fig. 10 (A).
Added 41.4 A' of water and cooked rice.

The outer diameter of the inner pot 1 is approximately 1000 mm, and the depth is approximately 300 mm.
, the outer diameter of the outer pot 2 is approximately 1050 mm, and the same depth is approximately 600 m.
m, the size of the heating section 3 is 120 mm 1 length 650 mm
Uses 3 bottles, heating capacity 3QKw, and salad oil for 150 liters as a heat medium! used. Both the inner and outer pots were made of stainless steel.

The results are shown in FIG. As is clear from Fig. 11, the temperature inside the pot is almost like the ideal temperature change curve shown in Fig. 9, and the temperature in the pot is 36% in 65 minutes! I was able to cook two (2) tons of rice. The quality of the cooked rice was similar to the rice cooked by an expert in the oven shown in Figure 8, confirming that the automatic rice cooker shown in Figures 1 to 3 was excellent.

As explained above, according to this embodiment, the following advantages can be obtained.

■ A heating medium is sealed in the outer pot, and rice is cooked in the inner pot by heating the heating medium, so a large amount of heat can be transferred in a short time, and the temperature can be raised with excellent temperature control. be able to. Furthermore, since a low frequency electromagnetic induction heating section is provided in any part of the outer pot, a large amount of heat can be efficiently generated in a short period of time. Furthermore, since the outer pot and the inner pot are integrated, the heating section and the heating medium are enclosed, making it possible to provide a safe device.

■ The power supply to the coil part of the low frequency electromagnetic induction heating part is
Since a commercial wave number AC power source (50 Hz or 60 Hz) is used, the device cost can be reduced and the device can have excellent durability.

■ Since edible oil is used as the heat medium, the device can be highly hygienic and safe.

■ A support shaft is provided on the side of the outer pot or inner pot, and an automatic reversing means is provided via the support shaft, so the entire pot can be automatically reversed, making it easy to take out cooked rice and wash it. etc. can be easily done.

■ A pre-cooking area where the temperature of the rice in the inner pot is maintained at 62°C or below for 10 minutes or more, and a cooking area where the temperature of the rice in the inner pot is maintained at a temperature of over 62°C and around the boiling point of water for 20 minutes or more. Since it is equipped with a control means consisting of a steaming area and a steaming area that holds the heat medium in a state where heating is stopped, the temperature of the pot can be automatically controlled, and rice with a constant cooked quality can always be obtained. .

(2) The automatic rice cooker of this embodiment is useful not only for cooking rice, but also as a miso soup pot, soup kettle, boiling pot, and other various heating cookers.

[Effects of the Invention] As explained above, according to the present invention, there is provided a heating cooker in which an outer pot and an inner pot are integrated and the cooking material is heated in the inner pot. It is equipped with a heating section that uses electric power as a heating source, a heat medium is sealed between the outer pot and the inner pot, and a means for heating the inner pot via the heat medium is provided, so that a large amount of heat can be generated. It can be moved in a short time, has excellent temperature control, and can raise the temperature without local heating. As a result, the excellent effect of improving the cooking environment with less heat radiation and exhaust heat can be achieved.

[Brief explanation of drawings]

Fig. 1 is a front view of an automatic rice cooker according to an embodiment of the present invention;
3 is a diagram showing the reversing mechanism, FIG. 4 is a perspective view showing a model of the low-frequency electromagnetic induction heating section, FIG. 5 is a sectional view of the heating pipe, and FIG. A) to (E) are example wiring diagrams that can be used, Figures 7 (A) to (B) are diagrams explaining the heat generation principle, Figure 8 is a diagram showing the temperature state when using a furnace, Fig. 9 is a diagram showing an ideal temperature curve inside the pot, Figs. 10 (A) to (C) are control flowcharts of an embodiment of the present invention, and Fig. 11 is a diagram showing the temperature state of the same experimental example. . 1... Inner pot, 2... Outer pot, 3... Low frequency electromagnetic induction heating section, 4... Heat medium, 5, 5'... Support shaft, 6.
7... Machine base, 8.8-... Bearing box, 9
...Casing part, 10...Arm fixing part, 11
...Pipe, 13...Part of machine anchor, 14...
Heat medium supply part (safety valve), 15...lid part, 17-19
... Gear, 16 ... Motor, 20 ... Screw shaft,
21...Screw holder, 22...Arm, 31...
- Iron core, 32... Induction coil, 33... Metal heating pipe, 34... Copper pipe, 34... Stainless steel pipe, 36... Flow of magnetic flux, 37... Flow of current. 16... Motor 20... Screw shaft Fig. 3 Transformer primary side Secondary side 100 times 100 times Fig. 7 (A) Principle of the present invention Induction coil Sea bream pipe Fig. 7 (B) Sections 1-8 Ideal temperature change curve for rice cooker Figure 9 Time difference) Figure 11 Time m > Figure 10 (A) Control stage (1 to 7) Soaking time 60℃ control time 110℃ control time After turning off the heat Time Oil temperature Pot bottom temperature Steam port temperature Buzzer Figure 10 (B) Figure 10 (C)

Claims (1)

[Scope of Claims] (1) A heating cooker in which an outer pot and an inner pot are integrated and the inner pot heats cooking ingredients, wherein electric power is used as a heating source for any part of the outer pot. 1. A heating cooking device comprising a heating section, a heat medium sealed between an outer pot and an inner pot, and means for heating the inner pot via the heat medium. (2) The cooking device according to claim 1, wherein the heating section using electric power is a low frequency electromagnetic induction heating section. (3) The cooking device according to claim 2, wherein power is supplied to the coil section of the low-frequency electromagnetic induction heating section from an AC power source at a commercial frequency. (4) The cooking device according to claim 1, wherein the heat medium is edible oil. (5) The heating cooker according to claim 1, further comprising a support shaft on a side of the outer pot or the inner pot, and an automatic reversing means provided via the support shaft. (6) Claim 1 wherein the heating cooker is a commercial automatic rice cooker.
The heating cooker mentioned. (7) Pre-cooking area where the temperature of the rice in the inner pot is maintained at 62℃ or less for 10 minutes or more, and cooking area where the temperature of the rice in the inner pot is maintained at a temperature of more than 62℃ and near the boiling point of water for 20 minutes or more. 7. The heating cooker according to claim 6, further comprising a control means comprising a raising region and a steaming region for holding the heat medium in a state where heating is stopped.