JP2712864B2 - Cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe type heating cooker used for a rice cooker or the like.

[0002]

2. Description of the Related Art For cooking containers such as rice cookers, various types of so-called heat pipe type heating cookers have been proposed in order to improve the heating temperature distribution. This heat pipe type cooking device has a closed double wall structure, and a working liquid such as water, which changes into a gas to a liquid due to a temperature difference, is sealed in a closed space between the outer wall and the inner wall. During cooking, the heat applied from the heat source evaporates and evaporates the hydraulic fluid at the bottom of the outer wall, condenses this vapor on the inner wall, and uniformly transfers heat to the entire inner wall, making the heating temperature uniform. And cook rice without uneven heating.

[0003] heating of the hydraulic fluid in the heating cooker of this heat pipe type is method for heating the bottom surface of the heat pipe of has an outer wall, such as a sheathed heater in is common, the heater in this manner is heat Most of the heat is radiated to the outside, resulting in poor heating efficiency. Therefore, instead of using an electric heater such as a sheath heater, a heating cooker that heats an inner pot by an electromagnetic induction method has been developed.

FIG. 2 is a cross-sectional view showing the configuration of a conventional electromagnetic induction heating cooker disclosed in, for example, Japanese Patent Application Laid-Open No. 1-223687 "Cooking Container for Electromagnetic Cooker". An outer wall (outer container) 2 formed by pressing a stainless steel plate or the like which is a magnetic material is an inner wall (inner container), and the outer wall 1a and the inner wall 2 are hermetically welded at an upper end 3 to form an outer wall 1a.
A sealed space evacuated is formed between the inner wall 2 and the inner wall 2.

[0005] 4a is a liquid reservoir formed on the bottom of the outer wall 1a, 5 is a working fluid such as water sealed in a predetermined amount in the liquid reservoir 4a, and 6a is an induction heater disposed below the bottom of the outer wall 1a for induction heating. A coil 7 indicates a high-frequency power supply connected to the coil 6a.

The conventional heating cooker shown in FIG. 2 is constructed as described above. When a primary current is applied to the coil 6a from the high frequency power supply 7, the outer wall 1 facing the coil 6a is formed.
An eddy current is generated by the electromagnetic induction action on the bottom surface of a, and a hysteresis loss is further added. The opposite bottom surface of the outer wall 1a generates heat, and the working fluid 5 in the liquid reservoir 4a is heated and boiled to be vaporized.

The boiling and vaporized working fluid 5 diffuses into the closed space between the outer wall 1a and the inner wall 2, condenses and liquefies at a portion of the inner wall 2 where the temperature is low, and radiates latent heat of condensation to this portion.
That is, a large amount of condensation of the working fluid 5 occurs in a lower temperature portion, and as a result, the temperature distribution of the inner wall 2 can be made uniform. Then, the hydraulic fluid 5 condensed in the low temperature portion of the inner wall 2 falls by its own weight, is heated again in the liquid reservoir 4a and is vaporized, and heats the low temperature portion of the inner wall 2, and this cycle is repeated. Then, an object to be heated (not shown) inside the inner wall 2 is uniformly heated.

[0008]

The problem to be solved is that the conventional heating cooker has insufficient heating efficiency. That is, as shown in FIG. 2, since the magnetic material is used for the outer wall 1a for performing the electromagnetic induction, the temperature at the time of heating becomes highest because of the outer surface of the outer wall 1a where the most current flows due to the skin effect. Thus, there is a problem in that heat radiation to the outside is large and a sufficiently high heating efficiency cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a cooking device capable of realizing high heating efficiency.

[0010]

According to the present invention, there is provided a heating cooker in which a convex protrusion is formed on a part of the bottom surface of an outer wall made of a non-magnetic material, and the protrusion serves as a liquid reservoir for storing a hydraulic fluid. The most important feature is that a heating element made of a magnetic material is provided at a predetermined position of the liquid reservoir, and the heating element is immersed in the working fluid.

[0011]

According to the present invention, heat generation immersed in the hydraulic fluid
By electromagnetically heating the body, it becomes possible to directly heat the working fluid by the heat generated by the heating element.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a heating cooker according to an embodiment of the present invention. In the drawing, reference numeral 1 denotes an outer wall (outer container) formed of a non-magnetic material, and 2 denotes a non-magnetic material. The inner wall (inner container), the outer wall 1 and the inner wall 2 are hermetically welded at the upper end 3, and a vacuum-evacuated sealed space is formed between the outer wall 1 and the inner wall 2.

4 is a liquid reservoir formed on the bottom surface of the outer wall 1,
The liquid reservoir 4 has a shape in which an outer peripheral portion of the bottom surface of the outer wall 1 is protruded downward in a donut shape so that a heating element described later is disposed at a predetermined position. Reference numeral 5 denotes a working fluid such as water sealed in a predetermined amount in the liquid reservoir 4, reference numeral 6 denotes a coil for induction heating disposed opposite to a position of a heating element described later, and reference numeral 7 denotes a coil 6.
A high-frequency power supply 8 connected to the power supply 8 is a heating element formed of a magnetic material, and is disposed at a predetermined position of the liquid reservoir 4 with a circular cross section and is immersed in the enclosed hydraulic fluid 5. Structure.

The heating cooker of the present invention is configured as described above. When a primary current is applied to the coil 6 from the high frequency power supply 7, the heating element 8 in the liquid reservoir 4 generates heat by electromagnetic induction. The working fluid 5 is directly heated. The working fluid 5 operates in the same manner as a conventional cooking device, and heats the inner wall 2 uniformly.
As described above, in the present embodiment, the heating element 8 formed of the magnetic material heated by the electromagnetic induction is placed at the predetermined position in the liquid reservoir 4 formed on the bottom surface of the closed space between the outer wall 1 and the inner wall 2. The heating element 8 can directly heat the working fluid 5 by immersing the working fluid 5 in the sealed working fluid 5, so that high heating efficiency can be obtained.

In the above embodiment, the heating element 8 is described as a heating element having a circular cross section. However, the shape of the heating element may be a flat plate as long as it can receive the magnetic flux from the coil 6 efficiently. Any cross-sectional shape may be used. It is also possible to constitute the heating elements 8 of a porous material such as sintered metal, by a porous material, thereby promoting the boiling efficiency of working fluid 5 for bubble nuclei with porous material The advantage that can be obtained.

Further, in the above-described embodiment, the coil 6 is disposed below the liquid reservoir 4 on the outer wall 1, but a part of the liquid reservoir 4 is formed in a convex shape to form a groove. The heating element 8 may be heated from the side by embedding the coil 6 therein. With such a structure, the coil 6
, Induction heating can be performed more efficiently.

Further, in the above embodiment, the case where the present invention is applied to a rice cooker is described. However, it is needless to say that the present invention is not limited to a rice cooker, but can be applied to other heating cookers in general. .

[0018]

As described above, the heating cooker according to the present invention is provided with a heating element made of a magnetic material in the working fluid, so that the heating element having the highest temperature is immersed in the working fluid. There is an advantage that heat loss can be reduced and heating efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a conventional heating cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer wall 2 Inner wall 4 Liquid reservoir 5 Hydraulic fluid 6 Coil 7 High frequency power supply 8 Heating element

Claims (1)

(57) [Claims] 1. A cooking vessel for providing a closed space between an outer container and an inner container, enclosing a working fluid in the closed space to form a heat pipe, and heating the working fluid by an electromagnetic induction method. Means for forming both the outer container and the inner container with a non-magnetic material,
Means for forming a projecting portion on a part of the bottom surface of the outer container and using the projecting portion as a liquid reservoir for storing the hydraulic fluid; To that
A heating cooker including a heating element entirely immersed therein, wherein the heating element is heated by induction heating to heat the working fluid.