JP2700121B2 - Cooking vessel - 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 cooking container used for rice cookers and the like.

[0002]

2. Description of the Related Art In order to improve the heating temperature distribution in pots and rice cookers, various types of so-called heat pipe type cooking containers have been proposed. This heat pipe type cooking container has a closed double wall structure, in which a working fluid such as water, which changes into a gas to a liquid due to a temperature difference, is sealed in a closed space between an outer wall and an inner wall. It has become. At the time of cooking heating, the working fluid at the bottom of the outer wall is evaporated and vaporized by the heat applied from the heating source, this vapor is condensed on the inner wall, and the heat is uniformly transmitted to the entire inner wall, and the uniform heating temperature is measured. It is possible to cook rice without uneven heating.
FIG. 5 is a cross-sectional view showing a first conventional heating and cooking container disclosed in, for example, JP-A-52-23303 and JP-A-56-78716. In the drawing, reference numeral 1 denotes an outer wall formed by pressing a stainless steel plate or the like, 2 denotes an inner wall, and the outer wall 1 and the inner wall 2 are hermetically welded at an upper end portion 3;
A closed space that is evacuated is formed between them. 4
Is a liquid reservoir formed in a downwardly convex shape on the outer peripheral portion of the bottom surface of the outer wall 1, 5 is a working fluid such as water sealed in an appropriate amount in the liquid reservoir 4,
Reference numeral 6 denotes a porous wick having a capillary phenomenon such as a wire mesh or glass wool attached to the evaporating portion 7 and the condensing portion 8 on the surfaces of the outer wall 1 and the inner wall 2.

[0003] The first conventional heating and cooking container is constructed as described above, and an object to be heated such as water or rice put in the inner wall 2 is heated by a heating source such as an electric heater (not shown) and cooked. Is done. When the liquid reservoir 4 is heated by the heating source, the working fluid 5 boils and evaporates. This steam has a lower pressure,
That is, it moves at a sonic speed to the inner wall 2 where the temperature is low, where it condenses and liquefies and gives latent heat of condensation to the inner wall 2. Since a large amount of the hydraulic fluid 5 condenses in the lower temperature portion, the inner wall 2
Temperature becomes uniform. The hydraulic fluid 5 condensed on the inner wall 2 falls by gravity, returns to the liquid reservoir 4 again, and this cycle is repeated. The outer wall 1 as the evaporator 7 of the heat pipe
Of the hydraulic fluid 5 by the capillary action of the wick 6
Spreads to a position higher than the water surface of the liquid reservoir 4. A wick 6 stretched on the inner surface of the inner wall 2 as the condensing portion 8 of the heat pipe has a function of uniformly wetting the surface of the inner wall 2.

FIG. 6 is a partial sectional view of a second conventional cooking container viewed from a plane. In the figure, reference numerals 1 and 2 are the same as those in the first conventional example. Reference numeral 9 denotes a rod-like or tubular rib member vertically sandwiched between the outer wall 1 and the inner wall 2. Although not shown, similar rib members 9 are radially arranged on the bottom surface of the container. The rib member 9 is joined to the outer wall 1 and the inner wall 2 by spot welding or seam welding.

The second prior art is configured as described above, and the rib member 9 increases the internal pressure strength by mechanically connecting the outer wall 1 and the inner wall 2. Thus, the thickness of the outer wall 1 and the inner wall 2 can be reduced. Further, by thermally connecting the outer wall 1 and the inner wall 2, heat can be transmitted from the outer wall 1 side to the inner wall 2 side (during heating) or vice versa (during heat radiation) by conduction.

FIG. 7 is a partial sectional view showing a third conventional cooking container viewed from a plane. In the figure, reference numeral 2 is the same as the first and second conventional examples. The outer wall 1 is press-formed into a corrugated shape, and its valley bottom is joined to the inner wall 2 by seam welding or the like. Although not shown, a similar waveform is formed on the bottom surface of the outer wall 1.

The third conventional example is configured as described above, and the corrugation of the outer wall 1 operates in the same manner as the rib member 9 of the second conventional example.

[0008]

In the first conventional example as described above, the liquid of the hydraulic fluid 5 can be sucked up only at a slight height by the capillary action of the wick 6. The outer wall 1 functions as an evaporator 7 of the heat pipe.
If the hydraulic fluid 5 does not exist, the hydraulic fluid 5 cannot be evaporated. The surface of the dry-out outer wall 1 in which the working fluid 5 does not exist has a high temperature due to the heat from the heating source because there is no cooling action by the latent heat of evaporation of the working fluid 5. Since the heat from the heating source enters the outer wall 1 only from the surface where the liquid film of the working fluid 5 exists, if the area of the evaporator 7 is small, the thermal resistance increases and the temperature on the heating source side (for example, (Ambient air temperature), the heat radiation loss to the outside increases, and the heating efficiency decreases. Also, it has been difficult to adhere the wick 6 such as a wire mesh with good adhesion over a wide area of the outer wall 1 and the inner wall 2. Now, in the rice cooker, heat transfer from the inner wall 2 to the outer wall 1 after cooking rice is also important. Insulation temperature of rice in jar rice cooker is around 70 ° C,
The faster the temperature falls from 100 ° C. to 70 ° C. at the time of completion of rice cooking, the better. If the temperature drop rate is low, the yellowing of the rice due to the aminocarbonyl reaction proceeds during this time, and the rice ages, which is not preferable. In the case of a heat pipe that does not use a wick that directly connects the evaporating unit 7 and the condensing unit 8, heat transfer in the reverse direction due to the reverse cycle is small. That is, during heat radiation, the inner wall 2 becomes a high-temperature portion and the outer wall 1 becomes a low-temperature portion. However, since the hydraulic fluid 5 does not exist on the surface of the inner wall 2, it does not become an evaporating portion, and a reverse cycle is not established. The heat transfer from the inner wall 2 to the outer wall 1 was only radiation and convective heat transfer, and the amount of heat released was smaller than that of a normal single-walled container. .

In the second and third prior arts, although the pressure resistance is high, the heat transfer by conduction from the inner wall 2 to the outer wall 1 at the time of heat radiation can be ensured to some extent by the corrugation of the rib member 9 and the outer wall 1. The rib member 9 and the like did not contribute to the enlargement of the area of the evaporating portion during heating, similarly to the conventional example. This is because the hydraulic fluid 5 condensed on the inner wall 2 flows down along the rib members 9 and the like, and moves horizontally to move the outer wall 1.
Could not wet the sides. In the second conventional example, it is difficult to arrange a large number of rib members 9,
In the prior art, there is also a problem that the surface of the outer wall 1 has irregularities, so that the cleaning property when cleaning the container is poor.

The present invention has been made to solve such a problem, and an object of the present invention is to obtain a heating cooking container in which the area of the evaporating section is increased, the heating efficiency is increased, and the heat transfer amount during heat radiation is large. .

[0011]

In a cooking vessel according to the present invention, a wick is arranged between an outer wall and an inner wall so as to connect both walls.

The wick has a corrugated shape and is arranged in a direction that does not hinder the flow of the vapor and liquid of the working fluid.

[0013]

In the heating cooking container constructed as described above, at the time of heating, the hydraulic fluid condensed on the inner wall moves to the outer wall by the wick and enlarges the area of the evaporator. Also, during heat dissipation, the heat of the inner wall is transmitted through the wick to the outer wall.

The corrugated wick does not prevent passage of the working fluid vapor and liquid during heating.

[0015]

【Example】

Embodiment 1 FIG. FIG. 1 is a sectional view showing an embodiment in which the present invention is applied to an inner pot of a jar rice cooker, and FIG. 2 is a partial sectional view of the embodiment. Reference numerals 1 to 5 and 8 are exactly the same as those in the above-mentioned conventional example. Reference numeral 6 denotes a wick, which is, for example, a wire mesh made of a thin metal wire having high heat conductivity and having a spring effect, which is formed into a corrugated sheet shape by press molding, and is sandwiched between the outer wall 1 and the inner wall 2. The wick 6 is divided into a side portion and a bottom portion of the container. Reference numeral 7 denotes an evaporating section that covers a large area of the outer wall 1. The wire mesh wick 6 has the mesh of the wire mesh in the direction shown in FIG. Further, the wire mesh constituting the wick 6 may be formed by laminating a plurality of pieces.

In the cooking vessel having the above-described structure, a part of the working fluid 5 condensed and liquefied in the condensing portion 8 of the inner wall 2 is heated by the wick 6 on both the side portion and the bottom portion during heating.
It moves to the evaporating section 7 of the outer wall 1 facing the eye of the wire mesh. Therefore, the working fluid 5 repeats the circulation of evaporation and condensation without returning to the liquid reservoir 4. The working fluid 5 not caught by the wick 6 flows down by gravity and returns to the fluid reservoir 4. By such an operation, the area of the evaporating section 7 extends not only to the liquid storage section 4 but also to a wide range of the outer wall 1 to efficiently transmit heat from the heating source to the working fluid 5. Also, at the time of heat radiation, the wick 6 conducts heat by conduction from the inner wall 2 to the outer wall 1 to secure an amount of heat radiation. The wick 6 arranged on the bottom of the container carries the hydraulic fluid 5 in the liquid reservoir 4 to the bottom of the inner wall 2 by capillary action, where a reverse cycle of the heat pipe occurs to promote heat dissipation. By the way, in the rice cooker, the output of the electric heater is controlled according to the temperature of the object to be heated placed inside the inner wall 2. For this control, a temperature detector (not shown) is in contact with the center of the bottom surface (outer surface) of the outer wall 1. Although this temperature detector indirectly detects the temperature of the object to be heated inside the inner wall 2 from the outer wall 1 surface, a temperature difference usually occurs between the evaporator 7 and the condenser 8. If the temperature difference is not always constant, accurate control cannot be performed. However, due to the wicks 6 arranged on the bottom surfaces of the outer wall 1 and the inner wall 2, the working fluid 5 contracted by the condensing portion 8 of the inner wall 2 surely wets the evaporating portion 7 at the center of the bottom surface of the outer wall 1. The temperature difference is stable, and accurate temperature detection can be performed.
The wick 6 can be mounted only by inserting it between the outer wall 1 and the inner wall 2 and partially fixing the wick 6 due to the spring effect of the wick 6 itself. In addition, since the surfaces of the outer wall 1 and the inner wall 1 have no irregularities, the cleaning property is good.

Embodiment 2 FIG. FIG. 4 shows another embodiment of the wick 6, in which a wire mesh wick 6 is formed into a rectangular or trapezoidal shape by pressing. With such a shape, the contact area between the wick 6 and the outer wall 1 and the inner wall 2 is increased, and the transfer of the hydraulic fluid 5 and the conduction during heat radiation are further improved.

Embodiment 3 FIG. In the first and second embodiments, the gaps between the folding of the corrugated plate or the rectangular / trapezoidal wick 6 are set at the same pitch, but may be a combination of a short pitch and a long pitch. With such a structure, the vapor of the working liquid 5 rises at a long pitch where the passage resistance is small, and the condensed liquid falls at a short pitch. Therefore, the working fluid 5 is efficiently circulated without the steam and the liquid facing each other in the same passage.

Embodiment 4 FIG. In the first and second embodiments, the wick 6 has a wire mesh shape, but may be a thin plate made of a sintered metal or a foamed metal.

Embodiment 5 FIG. Further, in each of the above embodiments, the wick 6 is inserted and arranged only between the outer wall 1 and the inner wall 2, but a flat second wick is attached to the outer wall 1, the inner wall 2, or both surfaces of the outer wall 1 and the inner wall 2. Further outer wall 1
The first wick used in the first and second embodiments may be disposed between the first wick and the inner wall 2. By doing so, the number of parts increases, but more of the working fluid 5 condensed on the inner wall 2 moves to the outer wall 1 side, and the surface of the outer wall 1 can be uniformly wetted. Since the second wick is pressed by the first wick, no special fixing is required.

In the above description, the case where the present invention is applied to a jar rice cooker has been described, but it goes without saying that the present invention can also be used for other heating containers for cooking.

[0022]

Since the present invention is configured as described above, the following effects can be obtained.

By sandwiching the wick made of a heat transfer material between the outer wall and the inner wall, the area of the evaporating portion at the time of heating can be enlarged and the heating efficiency can be improved. The wick also increases the amount of heat radiation during heat radiation and can prevent yellowing of the rice.

Further, since the wick has a corrugated shape parallel to the flowing direction of the working fluid vapor and the liquid, the operation of the heat pipe is not hindered by the wick.

[Brief description of the drawings]

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

FIG. 2 is a partial sectional view of FIG. 1 as viewed from above.

FIG. 3 is an enlarged sectional view of the wick of FIG. 1;

FIG. 4 is a partial cross-sectional view of Embodiment 2 of the present invention as viewed from a plane.

FIG. 5 is a cross-sectional view showing a first conventional heating cooking container.

FIG. 6 is a partial cross-sectional view of a second conventional cooking container as viewed from above.

FIG. 7 is a partial cross-sectional view of a third conventional cooking container viewed from a plane.

[Explanation of symbols]

 1 outer wall 2 inner wall 5 hydraulic fluid 6 wick

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshinobu Hoshino 1-2-1 Wadazakicho, Hyogo-ku, Kobe, Mitsubishi Electric Corporation Kobe Works (72) Inventor Hisaaki Yamakage 1-chome, Wadazakicho, Hyogo-ku, Kobe-shi No. 1-2 Mitsubishi Electric Corporation Kobe Works (72) Inventor Tetsuro Ogushi 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Corporation Central Research Laboratory (72) Inventor Masaaki Murakami 8-1-1 Tsukaguchi Honcho Amagasaki City No. 1 Mitsubishi Electric Corporation Central Research Laboratory (56) References JP-A-49-125174 (JP, A) JP-A-62-243515 (JP, A) JP-A-1-230310 (JP, A)

Claims (2)

(57) [Claims] 1. A heat pipe-type cooking vessel in which a sealed space is formed between an outer wall and an inner wall and a working fluid that undergoes a phase change accompanying heat radiation is enclosed in the space. A wick for transferring the working fluid condensed on the inner wall to the outer wall facing the inner wall. 2. The method according to claim 1, wherein the wick is formed into a corrugated plate or a rectangular or trapezoidal shape, and is disposed between the outer wall and the inner wall in a direction that does not impede the flow of the vapor and liquid of the hydraulic fluid.
The heating cooking container according to the item.