JPS63229006A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a two-base rice cooker used in general households, and particularly to a rice cooker with improved cooking performance using an electric heater.

Conventional technology Traditionally, two types of electric heaters have been mainly used for rice cookers: (1) cast aluminum heaters in which a sheathed heater is embedded in cast aluminum; and (2) sheathed heaters (high temperature type). When using a cast aluminum heater, a direct heating method is used where the pot and electric heater come into direct contact, and when using a sheathed heater (2), an indirect heating method is used where the pot and electric heater do not come into contact. The reality is that the position of the pot and electric heater is changed depending on the type of electric heater used.

However, in the direct heating method (1) using a cast-aluminum heater, the pot and electric heater are in contact with each other, so although the thermal efficiency is excellent, heat transfer from the electric heater to the pot occurs through thermal conduction. Unbalanced heat transfer occurs depending on the degree of contact between the pot and the electric heater, as well as the temperature sensor installed in the center of the electric heater and the top part of the pot.

As a result, there is a problem in that the rice tends to be cooked unevenly and the overall taste deteriorates.

In addition, strict dimensional accuracy is required to ensure that the electric heater and pot are in close contact with each other, resulting in high costs and furthermore, problems such as deformation or corrosion during use.

There is a problem in that if the heat transfer becomes further unbalanced, the uneven cooking phenomenon becomes even worse.

On the other hand, in the indirect heating method (2) that uses a high-temperature type sheathed heater, heat transfer from the electric heater to the pot occurs through thermal radiation, so the parts near the electric heater become sticky and There was a problem in that the part farther away from the heater (the upper part of the pot) had uneven cooking, such as hardness, and the taste deteriorated.

Furthermore, in order to improve this, if the sheathed heater is made into a spiral shape, it will require modification to improve the flatness of the heater and fixing metal fittings, which will increase the cost.

Further, since the heat generating area of the heater is small, the temperature of the heater itself becomes high, and as a result, the heat shielding structure of the main body also has a drawback.

Therefore, in order to solve these problems, the present inventors developed a counter-circular top plate 20 made of a metal plate with a hole 20 in the center and a spiral top plate 20, as shown in FIG. It has a heating wire 21 wound into a shape, a groove 222L in which the heating wire 21 is arranged in a spiral shape, and a hole 22b in the center, and is made of a heat insulating material mainly composed of silica or alumina fiber. A heat insulating base 22, a bottomed cylindrical storage case 23 that houses the heat insulating base 22 and has a hole 232L in the center, and the top plate 2o and the storage case 23 are provided in their respective centers. Hole part 20&.

An electric heater is proposed, which comprises a fixing ring 24 fixed at 23'B-.

Furthermore, the authors have also proposed a rice cooker that uses this electric heater and in which the pot and the electric heater are positioned apart from each other with a certain heating space.

This rice cooker is structurally similar to the conventional indirect heating method using a sheathed heater, but while the former uses linear heat, it uses surface heating, and it cooks the pot more evenly. Can be heated. As a result, the structure is closer to that of an old-fashioned stove, and the heat from the electric heater is in ideal conditions, which not only improves the taste of the rice, but also significantly improves the problem of uneven cooking, which had been a problem in the past. Significant effects on rice cooking performance were obtained.

Problems to be Solved by the Invention However, the rice cooker using an electric heater that has already been proposed has the same problem as the indirect heating method using a sheathed heater.

(1) Poor thermal efficiency (2) The main body temperature becomes high.

Although the rice cooking performance is excellent, the two drawbacks mentioned above have been highlighted as major problems.

In view of these problems, it is an object of the present invention to provide a rice cooker that is excellent not only in rice cooking performance but also in thermal efficiency and heat shielding effect of the main body.

Means for Solving the Problems 6 B-1 In order to solve the above problems, the present invention provides a top plate made of a metal plate, a spirally wound heating wire, and a spiral arrangement of the heating wires. An electric heater consisting of a heat insulating base made of a heat insulating material mainly composed of silica-alumina fibers and a storage case made of a metal plate that houses the heat insulating base, A heating space is formed around the cooking pot by the protection frame, and the heating space is provided within the heating space at a predetermined distance from the cooking pot. A heater is provided, and the top plate of the electric heater is coated with a ceramic coating containing a metal oxide and mainly composed of silicon oxide, and the outer circumferential surface of the pot is black-treated.

Function The electric heater used in the present invention has a considerably wider heat generating area than the indirect heating method using a conventional sheathed heater, but since it is an indirect heating method,
Exposure to relatively high temperatures of 500-600°C. Therefore, the temperature of the atmosphere in the heating space also becomes significantly higher than in the direct heating method using an aluminum cast heater. Therefore, the temperature of the main body also tends to increase.

In addition, heat transfer from the electric heater to the pot is carried out by radiation, so if the cycle of heat radiation and absorption between the electric heater and the pot does not work well, the thermal efficiency will drop significantly and the heat from the electric heater will be transferred to the pot. As the heat is transmitted to other parts, the temperature of the main body also tends to rise.

However, in the present invention, the surface of the top plate of the electric heater is coated with a ceramic coating containing metal oxide and mainly composed of silicon oxide, and the outer circumferential surface of the pot is black-treated. Heat transfer from the heater to the pot occurs quickly, increasing thermal efficiency, and since the transfer of heat to the main body is suppressed, the main body temperature is also lowered, resulting in significant effects.

This is because the ceramic coating applied to the surface of the top plate has excellent heat radiation, and the black treatment applied to the outer circumferential surface of the pot has excellent heat absorption.

In addition, the ceramic coating applied to the top plate surface is
This is a surface treatment using the sol-gel method, which has not only excellent heat resistance and thermal shock resistance, but also excellent corrosion resistance due to its lack of pinholes, and has been traditionally used as a surface treatment. Effects that cannot be obtained with inorganic paints or silicone-based organic heat-resistant paints can be obtained.

On the other hand, the electric heater does not require any heat resistance to blacken the outer circumferential surface of the pot, and can be done with general black alumite or silicone-based organic heat-resistant paint.

For these reasons, the rice cooker of the present invention has excellent rice cooking performance such as good taste and even cooking, and is also excellent in thermal efficiency and heat shielding effect of the main body.

EXAMPLES Hereinafter, specific examples of the present invention will be described based on FIGS. 1 to 5. In the figure, reference numeral 1.1 indicates a substantially bottomed cylindrical main body with an open top, and a substantially cylindrical protective frame 3 serving as a pot storage area is disposed inside the main body 1 via a heat insulating material 2. Furthermore, the outer periphery of the upper end of the protective frame 3 is fitted into the annular upper frame 4 made of heat-resistant plastic, which is fitted around the inner periphery of the upper end of the main body 1 . Reference numeral 5 denotes a pot having an outwardly directed flange 6 formed on the upper opening edge, and the pot 5 is disposed within the protective frame 3 by placing the flange 6 on the upper surface of the upper frame 4. Further, the outer peripheral surface of the pot 5 is subjected to a black treatment 5a using black alumite using an inorganic heat-resistant dye.

7 is an electric heater, 8 is a top plate made of 5pcc, and a hole 82L is provided in the center of the top plate 8, and upside-down ribs Bb and sb' are formed on the inner and outer peripheral surfaces. Further, a female thread 8C is provided inside the outer peripheral surface.

Moreover, this top plate 8 has a convex spherical pressing of R=2000 as a whole, and is coated with a ceramic coating 8d containing metal oxide and mainly composed of silicon oxide.
is applied.

Reference numeral 9 denotes a heat insulating base made of a 10-page heat insulating material mainly composed of silica and alumina fibers, and this heat insulating base 9 is provided with a spiral groove 9a and a hole 9b in the center. Reference numeral 10 denotes a spirally wound heating wire, and this heating wire 10 is disposed in a groove 9a provided in the heat insulating base 9.

Reference numeral 11 denotes a storage case that stores the heat insulating board 9 on which the heating wire 1o is arranged. ribs 11b, 11b'
are provided on the inner circumferential surface and the outer circumferential surface, and a male thread 110 is provided on the outside of the outer circumferential surface.

12 includes a top plate 8, a heat insulating base 9 and a storage case 11;
Holes aa and gb in the center provided in each.

This is a fixing ring used when integrating 11&.

The electric heater 7 described above is supported at the bottom of the protective frame 3 by a support member (not shown). Moat electric heater 7
A heating space 13 exists between and the pot 6. 14
is a heat-sensitive element that detects the end temperature of rice cooking, and is attached to the protective frame 3.

Reference numeral 16 indicates a lever that is interlocked with the heat-sensitive element 14, and reference numeral 16 indicates a microswitch that controls energization of the electric heater 7, which is turned on and off by the lever 15.

17 is a display board, which is attached to the main body 1.

A button 18 is inserted into the lever 16.

Reference numeral 19 denotes a lid, and this lid 19 is attached to the upper opening of the main body 1 so as to be openable and closable.

Next, the operation of the rice cooker of the present invention having such a configuration will be explained. First, the washed rice and water are stored in the pot 6, and the pot 5 is stored in the protective frame 3.

Close the lid 19. Then, when button 18 is pressed, lever 15
rotates, the heat-sensitive element 14 linked to this lever 15 operates, and the rice cooking state is reached, and the micro switch 16
is turned on, and the electric heater 7 is energized.

When the electric heater 7 generates heat, the air in the sealed heating space 13 is heated, and the pot 5 is heated via this heated air. By heating this pot 5,
Rice is being cooked.

When all the water in the pot 6 is absorbed by the rice, the bottom of the pot 5 becomes empty and the temperature rises rapidly. At this time, the temperature of the thermal element 14 also rises, and the lever 16 is pushed down. As a result, the microswitch 11 is opened, the electricity to the electric heater 7 is stopped, and rice cooking is completed.

On the other hand, in order to evaluate the thermal efficiency and the temperature of the main body 1 in the rice cooker of the present invention, we used a conventional alumite-treated pot 6 and a top plate 8 of an electric heater 7.
The following table shows the results of a comparative evaluation of cases in which the ceramic coating 8d, which has excellent heat radiation, was not applied.

The thermal efficiency was evaluated by measuring the cooking time required to cook 1.871 rice under constant power consumption.

(Left below) 13be-2 Table: As shown in the table, by combining the black-treated pot 6 and the ceramic-coated top plate 7,
The rice cooking time was shortened, the thermal efficiency was increased, and the temperature of the main body 1 was lowered, resulting in an excellent heat shielding effect.

In addition, although we did not particularly evaluate the rice cooking performance, the combination of the present invention also tasted as good as the conventional one.
It was cooked well and was evenly cooked.

As described above, the rice cooker of the present invention not only has good taste and uniformity of cooking, but also has excellent thermal efficiency and heat shielding effect.

In the above embodiment, black alumite was used to blacken the pot, but the present invention is not limited to this, and other blackening methods may be used.

Effects of the Invention As is clear from the above description, the present invention has a top plate made of a metal plate, a spirally wound heating wire, and a groove in which the heating wire is arranged in a spiral manner. .

and an electric heater composed of a heat insulating base made of a heat insulating material mainly composed of silica-alumina fibers, a storage case made of a metal plate that houses the heat insulating base, a pot for storing food to be cooked, and the pot. a protective frame for accommodating the pot, the protective frame forms a heating space around the pot, the heater is provided within the heating space at a predetermined distance from the pot; The surface of the top plate is coated with a ceramic coating that contains metal oxide and whose main component is silicon oxide, and the outer surface of the pot is treated with black, so the rice cooking performance is 15 to 7. However, it is possible to provide a rice cooker that is significantly superior in thermal efficiency and heat shielding effect of the main body.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of a rice cooker showing an embodiment of the present invention;
Figure 2 is an enlarged sectional view of part A in Figure 1, Figure 3 is a sectional view of the electric heater in the same rice cooker, Figure 4 is an enlarged sectional view of part B in Figure 3, and Figure 6 is an enlarged sectional view of the electric heater in the same rice cooker. It is an exploded perspective view of an electric heater in a rice cooker. 3...Protective frame, 5...Pot, 5a...
...Black treatment, 7...Electric heater, 8...
...Top plate, 8d...Ceramic coating, 9...Insulation base, 9a...Groove, 1o
・°・・・°Heating wire, 11...Storage case, 1
3... Heating space section. Name of agent: Patent attorney Toshio Nakao and 1 other person7-
Electric heater 8 - Top plate 8d - Lamic coating? -Drunken state base 9o-Encounter 10-1 * * 11-m-Storage case Figure 3 Figure 5 Figure 4

Claims (1)

[Claims] A heat insulating base comprising a top plate made of a metal plate, a spirally wound heating wire, a groove for arranging the heating wire in a spiral shape, and a heat insulating material mainly composed of silica-alumina fibers. ,
The electric heater includes a storage case made of a metal plate that stores the heat insulating base, a pot that stores food to be cooked, and a protective frame that stores the pot, and the protective frame surrounds the pot. A heating space is formed in the heating space, and the electric heater is provided within the heating space at a predetermined distance from the pot, and the top plate of the electric heater contains a metal oxide and silicon oxide on the surface of the top plate. A rice cooker that has a ceramic coating as its main ingredient and a black coating on the outer surface of the pot.