CA2902674A1

CA2902674A1 - Inner pot and rice cooker having the same

Info

Publication number: CA2902674A1
Application number: CA2902674A
Authority: CA
Inventors: Shaoping HUANG; Hongtao Wang
Original assignee: Zhejiang Supor Electrical Appliances Manufacturing Co Ltd
Current assignee: Zhejiang Supor Electrical Appliances Manufacturing Co Ltd
Priority date: 2013-01-31
Filing date: 2014-01-24
Publication date: 2014-08-07
Also published as: CN103070616B; CN103070616A; WO2014117678A1; RU2015136023A; KR20150113120A; EP2950688A1

Abstract

A liner and a rice cooker having the same are provided. The liner has a shape of revolving body, the revolving generatrix of the revolving body comprises a sidewall curve segment (2) forming the sidewall inner surface of the liner, and the maximum curvature radius of the sidewall curve segment (2) is less than the maximum radius of transverse cross section of the revolving body. Since the maximum curvature radius of the sidewall curve segment (2) forming the sidewall inner surface of the liner is less than the maximum radius of transverse cross section of the revolving body, the area of the central region of the liner is enlarged. During heating, water on the sidewall of the liner flows towards the central region of the liner from various directions, and there is enough water in this central region to be supplemented to the surrounding sidewall, thereby improving the heat convection in the liner and developing a uniform temperature distribution in the liner.

Description

INNER POT AND RICE COOKER HAVING THE SAME
[0001] The present invention relates to the field of the electric or electromagnetic heating cookware, and particularly to a inner pot and a rice cooker having the same.

[0002] A rice cooker or an electric rice cooker generally has an inner pot which is used for holding the materials to be heated such as rice and water, etc., and the inner pot cooperates with a heating plate and a coil plate, thereby heating the materials held therein.

[0003] Currently, a spherical inner pot has already appeared. Document CN201308391Y describes an example of this spherical inner pot. As shown in FIG l, in the inner pot with a shape of revolving body, the revolving generatrix comprises a flanging segment 10, a sidewall circular-arc segment 20 and a straight-line segment 30, wherein the sidewall circular-arc segment 20 is for forming the sidewall inner surface of the liner pot, the circle center of the sidewall circular-arc segment 20 is situated on the revolving axis p, thus obtaining the spherical inner pot whose body has substantially a radius r. The inventor has found that, through careful analysis and research, the spherical inner pot can not form efficient heat convection during use.

[0004] As shown in FIG.2, the spherical inner pot during rice cooking process, the arc-shaped sidewall constituted by the sidewall circular-arc segment 20 can induce the hot water to flow towards the center of the inner pot (i.e. where the revolving axis p is located) respectively along the directions a and b, while the water in the center of the inner pot is supplemented to the surrounding sidewall, the flow of the water brings the convection of the heat. But in the heat convection, the surrounding hot water all flows towards the center of the inner pot, there is not enough water in the center of the inner pot to flow towards the sidewall, thus the efficient heat convection can not be formed, so that the temperature in the inner pot is not uniform.

[0005] Thus, it is needed to improve the aforesaid disadvantages present in the art.

[0006] The main object of the present invention is to provide a inner pot and a rice cooker having the same, the inner pot improves the heat convection and develops a more uniform temperature in the inner pot .

[0007] To achieve the above object, according to a first aspect of the invention there is provided a inner pot having a shape of revolving body, the revolving generatrix of the foregoing revolving body comprises a sidewall curve segment forming the sidewall inner surface of the foregoing inner pot, the maximum curvature radius of the foregoing sidewall curve segment is less than the maximum radius of transverse cross section of the revolving body.

[0008] According to another aspect, the foregoing sidewall curve segment is a sidewall circular-arc segment, the foregoing sidewall circular-arc segment has a sidewall circular-arc radius, the perpendicular distance between the circle center of the foregoing sidewall circular-arc segment and the revolving axis of the foregoing revolving body is greater than zero, and the foregoing circle center and the foregoing sidewall circular-arc segment are situated at the same side of the foregoing revolving axis.

[0009] According to another aspect, the ratio between the foregoing perpendicular distance and the sum of the foregoing perpendicular distance and the foregoing sidewall circular-arc radius is not less than 0.15 and not greater than 0.35.

[0010] According to another aspect, the foregoing inner pot has an opening portion, the ratio between the radius of the foregoing opening portion and the sum of the foregoing perpendicular distance and the foregoing sidewall circular-arc radius is not less than 0.85 and not greater than 0.95.

[0011] According to another aspect, the ratio between the radius of the foregoing opening portion and the sum of the foregoing perpendicular distance and the foregoing sidewall circular-arc radius is not less than 0.9 and not greater than 0.94.

[0012] According to another aspect, the foregoing revolving generatrix further comprises a first straight-line segment connected to the lower end of the foregoing sidewall circular-arc segment, the foregoing first straight-line segment is perpendicular to the revolving axis of the foregoing revolving body and is tangent to the foregoing sidewall circular-arc segment.

[0013] According to another aspect, the foregoing revolving generatrix further comprises a flanging segment connected to the upper end of the foregoing sidewall circular-arc segment, the foregoing flanging segment comprises a transitional circular-arc segment and a second straight-line segment.

[0014] According to another aspect, the circle center of the foregoing transitional circular-arc segment is located at the outside of the foregoing inner pot, the foregoing transitional circular-arc segment is smoothly connected with the foregoing sidewall circular-arc segment along a tangential direction to the foregoing sidewall circular-arc segment.

[0015] According to another aspect, the foregoing second straight-line segment is perpendicular to the revolving axis of the foregoing revolving body and extends towards the outside of the foregoing inner pot, and the foregoing second straight-line segment is tangent to the foregoing transitional circular-arc segment.

[0016] According to a second aspect of the invention there is provided a rice cooker, the foregoing rice cooker has the foregoing inner pot according to any of the foregoing first aspect.

[0017] According to the technical solution of the invention, since the maximum curvature radius of the sidewall curve segment forming the sidewall inner surface of the inner pot is less than the maximum radius of transverse cross section of the revolving body, so that the center of curvature of the maximum curvature radius of the sidewall curve segment is not situated on the central axis of the revolving body, but it has a certain distance from the revolving axis, the area of the central region of the inner pot is enlarged. During heating, when the water on the sidewall of the inner pot flows towards the central region of the inner pot from various directions, there is enough water in this central region to be supplemented to the surrounding sidewall, thereby improving the heat convection in the inner pot and developing a uniform temperature distribution in the inner pot.

[0018] The accompanying drawings of the specification are included to provide a further understanding of the invention and constitute a part of the invention, the exemplary embodiments of the invention and the description thereof are to explain the present invention, and are not to be construed as unduly limiting the invention. In the accompanying drawings:

[0019] FIG1 is a schematic illustration of the structure of the inner pot in the prior art;

[0020] FIG.2 is a schematic illustration of the heat convection of the prior art inner pot illustrated in FIG1;

[0021] FIG.3 is a schematic illustration of the structure of the inner pot of the invention;

[0022] FIG.4 is a schematic illustration of the heat convection of the inner pot illustrated in FIG.3.
DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] It should be noted that the features in the various embodiments of the invention may be combined with one another in case of absent express definitions or no collision. The present invention will now be illustrated in detail in connection with the embodiments with reference to the accompanying drawings.

[0024] To overcome the disadvantages of the inner pot in the prior art, the invention provides an improved inner pot having a new structure, which makes it possible to improve the heat convection therein.

[0025] FIG.3 is a schematic illustration of the structure of the inner pot of the invention. As shown in FIG.3, the inner pot has a shape of revolving body, the revolving body is formed by making the revolving generatrix rotate 360 degrees about the revolving axis o. FIG.3 actually shows any perpendicular section containing the revolving axis o, the right and left symmetrical portions across the revolving axis o can all act as a revolving generatrix, the left portion across the revolving axis o acting as a revolving generatrix will be described below.

[0026] Referring to Figure 3, at the left side of the revolving axis o, the revolving generatrix of the revolving body is constituted by a flanging segment 1, a sidewall circular-arc segment 2 and a first straight-line segment 3. Wherein the sidewall circular-arc segment 2 is the body portion of the entire revolving generatrix, which is for forming the sidewall inner surface of the inner pot. The sidewall circular-arc radius of the sidewall circular-arc segment 2 is r, the circle center is x, and the circle center x is not situated on the revolving axis o, but it has a certain perpendicular distance from the revolving axis o at the side adjacent to the sidewall circular-arc segment 2, i.e. the circle center x and the sidewall circular-arc segment 2 are situated at the same side of the revolving axis o. As shown in FIG 3, the perpendicular distance is L1/2.

[0027] From another point of view, the sidewall circular-arc segment 2 revolves around the revolving axis o, thereby forming a revolving surface, i.e. the sidewall inner surface of the inner pot, the maximum radius of revolution of the revolving surface is L2/2 which is greater than the sidewall circular-arc radius r of the sidewall circular-arc segment 2.
Referring to Figure 3, the maximum radius of revolution L2/2 is equal to the sum of the perpendicular distance L1/2 and the sidewall circular-arc radius r, i.e. L2=L1+2r.

[0028] Also, the first straight-line segment 3 is connected to the lower end of the sidewall circular-arc segment 2 and is perpendicular to the revolving axis o, and the first straight-line segment 3 is tangent to the sidewall circular-arc segment 2, so that the sidewall circular-arc segment 2 is smoothly connected with the first straight-line segment 3. The first straight-line segment 3 constitutes a major portion of the bottom inner surface of the inner pot.

[0029] Furthermore, the flanging segment 1 is connected to the upper end of the sidewall circular-arc segment 2 and comprises a transitional circular-arc segment and a second straight-line segment. The circle center of the transitional circular-arc segment is located at the outside of the wall surface of the inner pot, and the transitional circular-arc segment is smoothly connected with the sidewall circular-arc segment 2 along a tangential direction to the sidewall circular-arc segment 2. The second straight-line segment is perpendicular to the revolving axis o but extends towards the outside of the wall surface of the inner pot, and the second straight-line segment is tangent to the transitional circular-arc segment to ensure a smooth transition therebetween. The transitional circular-arc segment constitutes the inner surface of the transition portion between the sidewall and the pot edge of the inner pot. The second straight-line segment constitutes the upper surface of the pot edge of the inner pot.

[0030] Thus, the revolving generatrix constituted of a flanging segment 1, a sidewall circular-arc segment 2 and a first straight-line segment 3 can be used for constituting the entire inner surface of the inner pot and the upper surface of the pot edge of the inner pot. The outer surface of the inner pot and the lower surface of the pot edge of the inner pot can also be constituted with a similar revolving generatrix, so that the wall of the entire inner pot has a uniform thickness. Of course, different forms of the revolving axis can also be employed to constitute the outer surface and the lower surface.

[0031] On the perpendicular section shown in FIG.3, the revolving axis o is a symmetry axis, similarly, the revolving generatrix at the right side also has a flanging segment, a sidewall circular-arc segment and a first straight-line segment, wherein the sidewall circular-arc segment is for forming the sidewall inner surface of the inner pot, and the sidewall circular-arc radius of the sidewall circular-arc segment is r, the circle center is y.

[0032] The inventor has found that the magnitude of the perpendicular distance between the circle center x of the sidewall circular-arc segment 2 and the revolving axis o can affect the heat convection in the inner pot, thereby affecting the temperature distribution in the inner pot. In particular, as shown in FIG.3, when the perpendicular distance is greater than zero and the circle center x and the sidewall circular-arc segment 2 are situated at the same side of the revolving axis o, the heat convection in the inner pot can be improved. And when the ratio (L1/2) / (L1/2+r) between the perpendicular distance (L1/2) and the sum (L1/2+r) of the perpendicular distance and the radius of the sidewall circular-arc segment 2 is not less than 0.15 and not greater than 0.35, the most efficient heat convection can be formed in the inner pot provided by the invention. That is, when the shape of the inner pot satisfies the formula of 0.15 (L1/2)/(L1/2+r)0.35, the most efficient heat convection can be obtained in the inner pot.

[0033] FIG.4 is a schematic illustration of the heat convection of the inner pot illustrated in FIG.3. When the shape of the inner pot satisfies the above-stated formula, the center of the inner pot is no longer a single spherical center, but rather is a annular region which is edged by x and y respectively and whose radius is L1/2. During heating, the hot water on the four walls of the inner pot flows towards the annular region respectively along the directions c and d, meanwhile the water in the annular region flows towards the four walls, since the annular region has a larger volume than the spherical center in the prior art, so that enough water can be supplemented to the four walls to form an efficient heat convection. Also, when the annular region is too large, which can adversely prevent the water flow on the four walls from flowing towards the annular region, and thereby can affect the heat convection.

[0034] According to the technical solution of the invention, since the circle center of the sidewall circular-arc segment is no longer situated on the revolving axis, but it has a certain perpendicular distance from the revolving axis at the side adjacent to the sidewall circular-arc segment, the area of the central region of the inner pot is enlarged. During heating, when the water on the sidewall of the inner pot flows towards the central region of the inner pot from various directions, there is enough water in this central region to be supplemented to the surrounding sidewall, thereby improving the heat convection in the inner pot and developing a uniform temperature distribution in the inner pot.

[0035] By proceeding with the actual boiling test in the inner pot provided by the invention, the rice grains forms a heat convection having an annular region by the hot water flow, the water surface in the annular region in the center of the inner pot forms a concave shape, the strong heat convection makes the temperature in the inner pot more uniform, so that the expansion rate and water absorption of the rice in the various layers of the inner pot is substantially identical.

[0036] Moreover, when the shape of the inner pot of the invention satisfies the above-stated formula, compared with the spherical inner pot of the prior art, in the same height, the surface area of the inner pot of the invention increases 5-15%. This is particularly advantageous for the rice cooker using the principle of the electromagnetic heating, because the increasing of the surface area of the inner pot corresponds to increasing the heated area, the magnetically conductive layer on the outer surface of the inner pot can generate more eddy current in the high frequent magnetic field, the effective utilization efficiency of the electric energy is improved.

[0037] Furthermore, in the FIG.3, the inner pot has an opening portion, the diameter of the opening portion is L3 and the radius is L3/2. As described previously, the maximum radius of revolution of the sidewall inner surface of the inner pot is L2/2, L2 is actually equal to L1+2r, i.e.
L2 is twice as much as the sum of the perpendicular distance between the circle center x of the sidewall circular-arc segment 2 and the revolving axis o and the radius of the sidewall circular-arc segment 2.

[0038] It is possible to obtain the inner pots with different opening-shrinkage rates by adjusting the ratio between L3 and L2, i.e. the ratio between the radius of the opening portion of the inner pot and the maximum radius of revolution of the sidewall inner surface of the inner pot embodies the opening-shrinkage degree of the inner pot, a lower ratio indicates a greater opening-shrinkage degree of the inner pot, which can restrain the vapor on the pot wall portion not flowing towards the outside more efficiently. Of course, the opening-shrinkage rate must also not be too small, otherwise it can bring difficulty to the processing of the inner pot itself and the installation of the inner pot in the rice cooker.

[0039] In the spherical inner pot of the prior art shown in FIG.1, the diameter of the opening portion is L3 and the radius is L3/2. In the inner pot provided by the invention, the opening portion also has a diameter L3 and a radius L3/2, but the maximum radius of revolution of the sidewall inner surface of the inner pot is increased than that of the prior art, thereby the opening-shrinkage rate of the inner pot is decreased. The inventor has found that the inner pot has a more suitable opening-shrinkage rate when the opening-shrinkage rate, i.e. the ratio between L3 and L2 (also i.e. L3/2 : L1/2+r) is not less than 0.85 and not greater than 0.95, in this case, it can not only restrain the vapor on the pot wall portion not flowing towards the outside efficiently, but is also easy to process and install, thereby a proper balance point between improving heating function and facilitating manufacturing installation is found.
Preferably, the inner pot has a most suitable opening-shrinkage rate when the above ratio is not less than 0.9 and not greater than 0.94.

[0040] The inner pot of the invention has been described above according to the embodiments, but the inner pot is not limited to just the components and the connection relationship described in the embodiments, for example, the sidewall circular-arc segment can be not limited to the circular arc segment having a fixed radius, can be a sidewall curve segment having different radii of curvature, as long as the maximum curvature radius of the sidewall curve segment is less than the maximum radius of transverse cross section of the inner pot; wherein the present several formulas are all preferred embodiments, the invention is not limited to just this, but can make appropriate extensions and changes according to the design principle of moderately enlarging the area of the central region of the inner pot.

[0041] Thus, in the inner pot with a shape of revolving body, the maximum curvature radius of the sidewall curve segment forming the sidewall inner surface of the inner pot is less than the maximum radius of transverse cross section of the revolving body, so that the center of curvature of the maximum curvature radius of the sidewall curve segment is not situated on the central axis of the revolving body, but it has a certain distance from the revolving axis, the area of the central region of the inner pot is enlarged. During heating, when the water on the sidewall of the inner pot flows towards the central region of the inner pot from various directions, there is enough water in this central region to be supplemented to the surrounding sidewall, thereby improving the heat convection in the inner pot and delevoping a uniform temperature distribution in the inner pot.

[0042] The invention also relates to a rice cooker, any one of the preceding embodiments and its variant inner pot. In fact, the said inner pot provided by the invention is suitable for the electric or electromagnetic heating cookware such as a rice cooker, an electric rice cooker, an electric cooker, an electric pressure cooker and the like, also suitable for the cookware that holds the articles to be heated with the inner pot and heats the articles directly or indirectly with the inner pot.

[0043] The above description are only preferred embodiments of the invention and are not intended to be limiting, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modifications, alternatives and improvements made within the spirit and the principle of the present invention should be included within the scope of protection of the invention.

Claims

1. A inner pot having a shape of revolving body, characterized in that the revolving generatrix of the revolving body comprises a sidewall curve segment forming the sidewall inner surface of the inner pot, the maximum curvature radius of the sidewall curve segment is less than the maximum radius of transverse cross section of the revolving body.

2. The inner pot according to claim 1, characterized in that the sidewall curve segment is a sidewall circular-arc segment (2) which has a sidewall circular-arc radius (r), the perpendicular distance between the circle center (x) of the sidewall circular-arc segment (2) and the revolving axis (o) of the revolving body is greater than zero, and the circle center (x) and the sidewall circular-arc segment (2) are situated at the same side of the revolving axis (o).

3. The inner pot according to claim 2, characterized in that the ratio between the perpendicular distance and the sum of the perpendicular distance and the sidewall circular-arc radius (r) is not less than 0.15 and not greater than 0.35.

4. The inner pot according to claim 2, characterized in that the inner pot has an opening portion, the ratio between the radius of the opening portion and the sum of the perpendicular distance and the sidewall circular-arc radius (r) is not less than 0.85 and not greater than 0.95.

5. The inner pot according to claim 4, characterized in that the ratio between the radius of the opening portion and the sum of the perpendicular distance and the sidewall circular-arc radius (r) is not less than 0.9 and not greater than 0.94.

6. The inner pot according to claim 2, characterized in that the revolving generatrix further comprises a first straight-line segment (3) connected to the lower end of the sidewall circular-arc segment (2), the first straight-line segment (3) is perpendicular to the revolving axis (o) of the revolving body and is tangent to the sidewall circular-arc segment (2).

7. The inner pot according to claim 2, characterized in that the revolving generatrix further comprises a flanging segment (1) connected to the upper end of the sidewall circular-arc segment (2), the flanging segment (1) comprises a transitional circular-arc segment and a second straight-line segment.

8. The inner pot according to claim 7, characterized in that the circle center of the transitional circular-arc segment is located at the outside of the inner pot, the transitional circular-arc segment is smoothly connected with the sidewall circular-arc segment (2) along a tangential direction to the sidewall circular-arc segment (2).

9. The inner pot according to claim 7, characterized in that the second straight-line segment is perpendicular to the revolving axis (o) of the revolving body and extends towards the outside of the inner pot, and the second straight-line segment is tangent to the transitional circular-arc segment.

10. A rice cooker, characterized in that the rice cooker has the inner pot according to any one of claims 1 to 9.