Electric kettle

Abstract

The invention provides an electric kettle which is provided with a shell and an inner container containing liquid, the inner container comprises an inner container bottom and an inner container body extending from the upper edge of the inner container bottom to an inner container opening, a temperature controller is arranged in the middle of the outer surface of the inner container bottom, and a heating piece is arranged on the outer surface of the inner container bottom and located on the outer side of the temperature controller. The inner surface of the inner container bottom is an outwards-protruding arc-shaped face, the radius of the upper edge of the arc-shaped face is r, the curvature radius of the arc-shaped face is R, and R / r is larger than or equal to 1.25 and smaller than or equal to 2.5. Through reasonable arrangement of the shape of the inner surface of the inner container bottom, it can be guaranteed that the electric kettle can efficiently boil water and meanwhile has low noise, and balance of noise reduction and heating efficiency is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of household appliances, and in particular to an electric kettle. Background Art

[0002] Electric kettles, a common water-boiling appliance, are widely used in Chinese households. As people's pursuit of a higher quality of life increases, the noise level of electric kettles has become a key consideration for consumers. Currently, electric kettles on the market are known to generate considerable noise, particularly high-power models (over 1500 watts), which can reach as high as 70 decibels, significantly impacting the user experience.

[0003] Research has found that the noise from boiling water in an electric kettle mainly comes from the bursting sound of bubbles generated when the water boils and rises to the surface of the liquid. Therefore, existing technologies mostly reduce noise from the perspective of reducing the probability of bubble generation. For example, the probability of bubble generation is reduced by reducing the heating power, the rate of bubble generation is suppressed by providing a coating on the surface of the inner pot of the electric kettle, and the shape of the inner pot of the electric kettle is optimized by providing an inclined surface or curved surface on the bottom of the inner pot to merge small bubbles into large bubbles, thereby reducing the number of bubbles. The above solution can greatly improve the noise problem when boiling water in an electric kettle by reducing the rate of bubble generation or the rate of bubble burst.

[0004] For example, Chinese patent CN201420057680.6 discloses an inner liner of a soybean milk machine, wherein the inner liner is composed of a metal barrel and a cup body assembly, the cross-section of the bottom of the cup body assembly is a trapezoidal structure that is narrow at the bottom and wide at the top, the angle between the hypotenuse and the straight side of the trapezoid is 5-60°, and the heating element is arranged on the hypotenuse. In this solution, since a hypotenuse is arranged at the bottom of the cup body assembly and the heating element is arranged on the hypotenuse, bubbles are preferentially generated on the hypotenuse, and the bubbles generated on the hypotenuse will slide along the oblique surface and merge into large bubbles, which greatly reduces the frequency of bubble bursting and effectively reduces noise. For another example, Chinese patent CN201020559732.1 discloses a soybean milk machine cup body (inner liner), wherein the bottom of the cup body is composed of a circular arc surface and a circular plane in the center, and the electric heating element is arranged on the circular arc surface. The bubbles generated on the circular arc surface will also slide along the circular arc surface and merge into large bubbles, which can also reduce noise. However, the transition between the central flat surface and the outer arc surface or inclined surface of the above two cup bodies is not smooth, which easily accumulates dirt, making it difficult to clean and providing a poor user experience.

[0005] The Chinese patent document CN202222997552.7 discloses a liquid heater, the inner surface of the bottom wall of the inner tank of which includes a smooth spherical surface. The smooth spherical surface not only reduces the noise when the electric kettle boils water, but also makes it difficult for dirt to accumulate on the spherical surface, greatly improving the convenience of user cleaning.

[0006] However, the above patent only considered reducing noise and the difficulty of cleaning when designing the inner liner of the electric kettle, and did not realize the impact of the change in the shape of the inner liner on the boiling speed of the electric kettle. The applicant's research found that for an electric kettle with a curved inner liner bottom, when the diameter of the inner liner remains unchanged, the steeper the curved surface, the larger the area of ​​the curved surface, the smaller the noise when the electric kettle boils water, and the slower the boiling speed of the electric kettle. It can be seen that the steepness of the curved surface of the inner liner bottom has opposite effects on the noise generated when the electric kettle boils water and the boiling speed. Therefore, how to design the shape of the inner liner of the electric kettle so that it takes into account noise reduction, easy cleaning and efficient water boiling is still a technical problem that needs to be solved urgently. Summary of the Invention

[0007] In order to solve the problem in the prior art that the bottom of the electric kettle inner tank is not designed to achieve a balance between noise, cleaning difficulty and heating speed, this application reasonably designs the inner tank structure of the electric kettle to achieve noise reduction and efficient water boiling without increasing the difficulty of cleaning.

[0008] In order to achieve the above-mentioned invention objectives, the present application is implemented in the following manner: The present application provides an electric kettle, comprising an outer shell and an inner liner for holding liquid, the inner liner comprising an inner liner bottom and an inner liner body extending from the upper edge of the inner liner bottom to the inner liner opening, a thermostat being provided in the middle of the outer surface of the inner liner bottom, a heating element being provided on the outer surface of the inner liner bottom on the outside of the thermostat, the inner surface of the inner liner bottom being an outwardly convex arc-shaped surface tangent to a horizontal plane, the width of the arc-shaped surface gradually increasing from bottom to top, the radius of the upper edge of the arc-shaped surface being r, the equivalent curvature radius of the arc-shaped surface being R, wherein 1.25≤R / r≤2.5.

[0009] By adopting the above scheme, the inner surface of the bottom of the inner pot of the electric kettle of the present application is a curved surface. On the one hand, the surface of the curved surface has a smooth transition, which is convenient for users to clean and improves the user experience; on the other hand, the curved surface is conducive to bubble aggregation, and the bubbles generated on the curved surface can easily slide along the curved surface and merge to form large bubbles, reducing the frequency of bubble rupture and thus reducing noise; the ratio of the equivalent curvature radius R of the curved surface of the present application to the radius r of the upper edge of the curved surface is controlled between 1.25 and 2.5. Such a setting can ensure that the electric kettle boils water efficiently while having lower noise, achieving a balance between noise reduction and heating speed.

[0010] The specific reason is that when the equivalent curvature radius of the curved surface is too large (greater than 2.5 times the radius r of the upper edge of the curved surface), the height of the curved surface is small, the curved surface is relatively flat, and the bubbles generated on the curved surface are not easy to accumulate, which leads to limited noise reduction effect when the electric kettle boils water. However, due to the small height of the curved surface, the heat dissipation area of ​​the outer surface of the inner bottom is also relatively small, and the heat generated by the heating element can be transferred more to the liquid in the inner tank, and the electric kettle has a higher heating efficiency when boiling water; when the equivalent curvature radius of the curved surface is too small (less than 1.25 times the radius r of the upper edge of the curved surface), the height of the curved surface is large, the curved surface is steeper, and the bubbles generated on the curved surface are easy to accumulate into large bubbles, which can significantly reduce the noise generated when the electric kettle boils water. However, due to the large height of the curved surface, the heat dissipation area of ​​the outer surface of the inner bottom is also large, and the heat generated by the heating element will be dissipated more, resulting in a decrease in the heating efficiency of the electric kettle. Therefore, only when the ratio of the equivalent radius of curvature R of the curved surface to the radius r of the upper edge of the curved surface is between 1.25 and 2.5 can the heat dissipation area outside the bottom of the inner pot be sufficient to not affect the heating speed of the heater, while also allowing bubbles to converge into large bubbles, effectively reducing noise and thus achieving a balance between heating noise and heating speed during operation of the electric kettle. This effect can be well verified when the diameter of the inner pot remains unchanged.

[0011] Preferably, the point on the arc surface that is 1 / 2r horizontally away from the center line of the bottom of the inner liner is point S, and the line connecting the points S divides the arc surface into a central inner arc surface and a peripheral outer arc surface. The inner liner is provided with a thermostat on the outer side corresponding to the inner arc surface, and the inner liner is provided with a heating element on the outer side corresponding to the outer arc surface. The inner surface of the bottom of the inner liner is divided into a middle inner arc surface and a peripheral outer arc surface. Since the outer arc surface is steeper than the horizontal plane, the heating element is provided on the outer side of the inner liner corresponding to the outer arc surface. Bubbles are more likely to form on the outer arc surface, which can effectively reduce noise. At the same time, the thermostat is provided on the outer side of the bottom of the inner liner corresponding to the inner arc surface. The inner arc surface is relatively flat relative to the horizontal plane, and the outer wall of the inner liner corresponding to the inner arc surface has smaller fluctuations. The temperature sensing piece of the thermostat fits more closely with the outer wall of the bottom of the inner liner, and the temperature sensing is more accurate. It is understandable that since the outer wall of the inner tank will dissipate heat outward, the water temperature in the side wall area of ​​the inner tank will be lower than the water temperature in the middle area of ​​the inner tank. Setting the heating element on the outside of the inner tank bottom corresponding to the outer arc surface can effectively increase the water temperature in the side wall area of ​​the inner tank, weaken convection, and thereby reduce the detachment of bubbles, further achieving the technical effect of noise reduction.

[0012] Preferably, the angle between the tangent line of the inner curved edge and the horizontal plane is A, where A is ≤ 30°. By controlling the angle between the tangent line of the inner curved edge and the horizontal plane to be less than 30°, the outer wall of the inner container corresponding to the inner curved surface is not too steep to affect the installation of the temperature sensing element of the thermostat, thereby balancing the user experience of consumers and the difficulty of production.

[0013] Preferably, the height of the inner curved surface is h1, h1≤5mm. The height h1 of the inner curved surface is controlled to be no greater than 5mm. In this way, the undulation of the inner curved surface will not be too large, and the undulation of the outer wall of the inner tank corresponding to the inner curved surface will be even smaller, which can ensure that the temperature sensing element of the thermostat can be reliably installed.

[0014] Preferably, the height of the outer curved surface is h2, where h2 is ≥ 7 mm. The outer curved surface has a height of no less than 7 mm and a certain degree of steepness, so that bubbles generated on the outer curved surface can easily slide along the surface of the outer curved surface and merge into large bubbles, ensuring that the electric kettle can effectively reduce noise when boiling water. Moreover, if the outer curved surface is too short, the heating element disposed on the outer curved surface will easily protrude from the lower surface of the outer wall of the inner pot, occupying too much installation space and not conducive to efficient space utilization.

[0015] Preferably, the radius of curvature of the inner curved surface is greater than that of the outer curved surface. The inner curved surface is smoother than the outer curved surface, while the outer curved surface is steeper than the inner curved surface. The heating element is disposed on the outer wall of the inner container corresponding to the outer curved surface. Large bubbles are more likely to accumulate on the outer curved surface, resulting in a more significant noise reduction effect.

[0016] Preferably, the inner and outer surfaces of the inner bottom are configured to conform to the shape of the kettle. The inner and outer surfaces of the inner bottom are configured to conform to the shape of the kettle, and the thickness of each area of ​​the inner bottom is the same, resulting in similar heat transfer efficiency. This reduces convection caused by temperature imbalance, thereby weakening bubble separation caused by convection fluctuations, and further reducing noise generated when the electric kettle boils water.

[0017] Preferably, the inner liner body is cylindrical, and the upper edge of the curved surface is tangent to the lower edge of the inner liner body. The inner liner body preferably adopts a cylindrical structure, such as a straight cylinder or a tapered cylinder (for example, a tapered cylinder with a larger bottom and a smaller top). This is convenient for the production of the inner liner body and also for the connection between the inner liner body and the curved surface. In particular, when the upper edge of the curved surface is tangent to the lower edge of the inner liner body, a continuous shape is formed between the inner liner body and the curved surface, which makes it easier for consumers to clean after use, thereby improving the user experience.

[0018] Preferably, the inner liner body includes a second inner liner body and a first inner liner body integrally formed with the upper edge of the curved surface, and the first inner liner body and the second inner liner body are connected by welding. In this way, the structure of integrally forming a portion of the inner liner body with the curved surface facilitates simultaneous connection of the curved surface and the transverse surface to the inner liner body during formation. Furthermore, the connection method of the inner liner body is simpler, the process difficulty is reduced, and it is conducive to industrialized manufacturing.

[0019] Preferably, the power of the heating element is no less than 1500W; or, the ratio of the power of the heating element to the maximum water boiling capacity of the electric kettle is no less than 1000W / L. For electric kettles with relatively high heating element power, or for electric kettles with relatively high heating element power per unit volume, the technical solution of this application can better achieve a balance between heating speed and noise reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the electric kettle of the present application.

[0021] Figure 2 It is a structural schematic diagram of the electric kettle liner of the present application.

[0022] Figure 3 It is a schematic diagram of the assembly of the electric kettle liner of the present application.

[0023] Figure 4 Graphs of noise and heating rate at different curvature radius ratios in Experiment 1 of this application are shown.

[0024] Figure 5 This is a graph of noise and heating rate at different curvature radius ratios in Experiment 2 of this application.

[0025] The meanings of the various marks in the figure are as follows: 1. Outer shell; 11. Handle; 2. Inner liner; 21. Inner liner body; 211. Inner liner body; 2111. First inner liner body; 2112. Second inner liner body; 212. Inner liner bottom; 2120. Arc surface; 2121. Outer arc surface; 2122. Inner arc surface; 22. Aluminum thermal conductor; 3. Heating element; 4. Thermostat. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the overall concept of the present application, a detailed description is given below in an illustrative manner in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0028] In addition, in the description of this application, it should be understood that the terms "center," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "axial," "radial," "circumferential," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Terms such as "upstream" and "downstream" are based on positional relationships during normal fluid flow.

[0029] Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0030] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0031] In this application, unless otherwise expressly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0032] An electric kettle generally includes a kettle body and a base. An upper coupler is provided at the bottom of the kettle body, and a lower coupler and power cord are provided on the base. When the kettle body is placed on the base, the upper and lower couplers couple to each other, thereby energizing the kettle body. The kettle body generally includes an outer shell 1 and an inner liner 2 disposed within the outer shell 1. A heater 3 is provided on the outer wall of the inner liner 2, which heats the inner liner 2, which contains water. Of course, there are also electric kettles in the prior art that have an integrated base and kettle body. In this type of kettle, the power cord is directly connected to the kettle body, eliminating the need for a separate base and resulting in lower costs.

[0033] Currently, electric kettles on the market generate a lot of noise when boiling water. Although the prior art discloses a method of reducing noise by providing an arc-shaped surface at the bottom of the inner pot, the change in the shape of the inner pot will affect the heating speed.

[0034] In order to solve the problem that the electric kettle in the prior art is not compatible with efficient heating and noise reduction, the present application provides an electric kettle, such as Figure 1-3 The electric kettle of the present application comprises an outer shell 1 and an inner liner 2 for holding liquid. The outer shell 1 is provided with a handle 11. The inner liner 2 comprises an inner liner bottom 212 and an inner liner body 211 extending from the upper edge of the inner liner bottom 212 to the opening of the inner liner 2. A thermostat 4 is provided in the middle of the outer surface of the inner liner bottom 212. A heating element 3 is provided on the outer surface of the inner liner bottom 212 outside the thermostat 4. The inner surface of the inner liner bottom 212 is an outwardly convex arc surface 2120 tangent to the horizontal plane. The width of the arc surface 2120 gradually increases from bottom to top. The radius of the upper edge of the arc surface 2120 is r, and the equivalent curvature radius of the arc surface 2120 is R. The value of R / r is between 1.25 and 2.5.

[0035] It can be understood that the radius r of the upper edge of the arc-shaped surface 2120 is the radius of the circle projected by projecting the upper edge of the arc-shaped surface 2120 onto the horizontal plane, which is the radius of the upper edge of the arc-shaped surface 2120 .

[0036] In the present application, the inner surface of the inner liner bottom 212 is a curved surface 2120. The curved surface 2120 is formed by a curve (generatrix) tangent to the horizontal plane rotating around the center line of the inner liner 2, for example, by a circular arc, an elliptical arc, an involute, etc. The equivalent radius of curvature R of the curved surface 2120 of the present application is the radius of an arc with a chord length of the radius r of the upper edge of the curved surface 2120 and an arc length of twice the length l of the generatrix of the curved surface 2120. The width of the curved surface 2120 gradually increases from bottom to top, which means that the distance between the generatrix of the curved surface 2120 and the center line of the inner liner bottom 212 gradually increases from bottom to top.

[0037] Because the inner surface of the inner liner bottom 212 of the electric kettle of the present application is a convex curved surface 2120, dirt is not easily accumulated on the curved surface 2120, making it easy to clean and providing users with a good cleaning experience. Compared to electric kettles with flat bottoms, bubbles generated on the curved surface 2120 easily slide along the curved surface 2120, and small bubbles merge into large bubbles, thereby reducing the frequency of bubble bursting and reducing the noise generated when the electric kettle boils water. It is understood that the convex curved surface 2120 refers to the arc center of the curved surface 2120 facing the inner side of the inner liner 2.

[0038] For electric kettles with an inner liner 2 having a convex curved surface 2120, the shape of the inner liner 2 affects both the noise level and the heating speed during boiling. Applicants have discovered that when the curved surface 2120 is steep, bubbles on the curved surface 2120 tend to converge, reducing the noise level during boiling. However, the steep curved surface 2120 results in a larger heat dissipation area on the outer surface of the inner liner bottom 212, causing more heat generated by the heating element 3 to be dissipated through the outer surface of the inner liner bottom 212, thus affecting the heating efficiency of the electric kettle. When the curved surface 2120 is flatter, the heat dissipation area on the outer surface of the inner liner bottom 212 is smaller, resulting in less heat dissipation through the outer surface of the inner liner bottom 212 and higher heating efficiency. However, an overly flat inner curved surface 2122 is not conducive to bubble aggregation, resulting in a relatively loud noise level during boiling. Only when the curved surface 2120 is appropriately shaped can a balance between heating efficiency and noise reduction be achieved.

[0039] Since both the noise level and heating efficiency of the electric kettle during boiling water are related to the steepness of the curved surface 2120, controlling the steepness of the curved surface 2120 can balance the contradiction between the noise level and the heating efficiency of the electric kettle during boiling water. However, how to control the steepness of the curved surface 2120 is an urgent problem that needs to be solved.

[0040] To control the steepness of the curved surface 2120, technicians typically consider controlling the height of the curved surface 2120 to influence its steepness. However, the height of the curved surface 2120 does not correspond to its steepness or area. Therefore, simply controlling the height of the curved surface 2120 is insufficient to resolve the conflict between noise reduction and heating efficiency when boiling water in an electric kettle.

[0041] The applicant's research found that when the radius of the upper edge of the curved surface 2120 remains unchanged, the curvature radius of the curved surface 2120 can not only affect the steepness of the curved surface 2120, but also affect the heat dissipation area of ​​the outer surface of the inner pot bottom 212. As the curvature radius of the curved surface 2120 changes, the steepness of the curved surface 2120 and the heat dissipation area of ​​the inner pot bottom 212 change in coordination. Therefore, the curvature radius of the curved surface 2120 can simultaneously affect the noise and heating efficiency when the electric kettle boils water.

[0042] By controlling the equivalent radius of curvature R of the curved surface 2120 to be between 1.25 and 2.5 times the radius r of the upper edge of the curved surface 2120, the present application ensures that the curved surface 2120 is neither too steep to affect the heating efficiency of the electric kettle when boiling water, nor too flat to affect the noise during boiling water, thereby achieving a reasonable balance between noise reduction and efficient heating, ensuring an optimal user experience. It is understood that when the ratio of the equivalent radius of curvature R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120 is less than 1.25, the curved surface 2120 is relatively flat, and although the heating efficiency is high when boiling water, the noise reduction effect is poor. When the ratio of the equivalent radius of curvature R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120 is greater than 2.5, the curved surface 2120 is relatively steep, and the noise reduction effect is improved when boiling water, but the heating efficiency is reduced. It can be seen from this that when the ratio of the equivalent curvature radius R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120 is less than 1.25 or greater than 2.5, it is not good for the consumer's usage experience.

[0043] In order to more clearly understand how to obtain the curvature radius R of the inner arc surface 2122, the following will be explained in conjunction with specific experiments:

[0044] Experiment 1

[0045] An electric kettle with a stainless steel inner body 21 is used. An aluminum heat conductor 22 is welded to the outer wall of the bottom of the inner body 21. The heating element 3 is a C-shaped heating tube, which is arranged around the outer wall of the aluminum heat conductor 22. The thermostat 4 is also arranged on the aluminum heat conductor 22, and the heating element 3 surrounds the outer circumference of the thermostat 4. The inner surface of the inner bottom 212 is a curved surface 2120.

[0046] The heating power of the electric kettle is kept at 1800 W, the radius r of the upper edge of the curved surface 2120 is kept at 64 mm, and the equivalent curvature radius R of the curved surface 2120 is kept at 128 mm. The heating speed and noise data of the electric kettle when boiling water with different shapes of the curved surface 2120 are shown in Table 1. Among them, the heating speed of the electric kettle is represented by the time required to heat 1.7 L of water from 40°C to 90°C.

[0047] Table 1: Heating rate and noise data corresponding to different curved surface shapes in Experiment 1.

[0048] Busbar shape Arc Elliptical arc Involute parabola Noise (db) 59.5 59.4 59.5 59.6 Heating speed (s) 227.2 227.1 227.3 227

[0049] Experiment 2

[0050] An electric kettle with a stainless steel inner body 21 is used. An aluminum heat conductor 22 is welded to the outer wall of the bottom of the inner body 21. The heating element 3 is a C-shaped heating tube, which is arranged around the outer wall of the aluminum heat conductor 22. The thermostat 4 is also arranged on the aluminum heat conductor 22, and the heating element 3 surrounds the outer circumference of the thermostat 4. The inner surface of the inner bottom 212 is a curved surface 2120, and the generatrix of the curved surface 2120 is an arc.

[0051] Keeping the heating power of the electric kettle at 1800W and the radius r of the upper edge of the curved surface 2120 at 64mm, the heating speed and noise data of the electric kettle when boiling water corresponding to different curvature radius ratios (ratio of the equivalent curvature radius R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120) obtained by changing the shape of the curved surface 2120 are shown in Tables 2 and Figure 4 , where the heating speed of the electric kettle is characterized by the time required to heat 1.7L of water from 40℃ to 90℃.

[0052] Table 2: Heating rate and noise data corresponding to different curvature radius ratios in Experiment 2.

[0053] Curvature radius ratio 1 1.1 1.2 1.25 1.3 1.4 1.5 1.75 2 2.5 2.75 3 Noise (db) 58.1 58.5 58.6 58.8 58.9 59 59.1 59.3 59.5 59.8 63.2 64.3 Heating speed (s) 236.2 235.1 234.3 230.5 229.8 229 228.5 228 227.2 226.8 226.5 226.2

[0054] Experiment 3.

[0055] The electric kettle features a stainless steel inner body 21. An aluminum heat conductor 22 is welded to the outer wall of the bottom of the inner body 21. The heating element 3 is a C-shaped heating tube, surrounding the outer wall of the aluminum heat conductor 22. The thermostat 4 is also mounted on the aluminum heat conductor 22, with the heating element 3 surrounding the outer periphery of the thermostat 4. The inner surface of the inner bottom 212 is a curved surface 2120, the generatrix of which is an elliptical arc. The upper edge of the curved surface 2120 is tangent to the lower edge of the inner body 211.

[0056] The heating power of the electric kettle is kept at 1600W and the radius r of the upper edge of the curved surface 2120 is kept at 55mm. The heating speed and noise data of the electric kettle when boiling water corresponding to different equivalent curvature radius ratios (ratio of the equivalent curvature radius R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120) obtained by changing the shape of the curved surface 2120 are shown in Tables 3 and Figure 5 , where the heating speed of the electric kettle is characterized by the time required to heat 1.5L of water from 40℃ to 90℃.

[0057] Table 3: Heating rate and noise data corresponding to different curvature radius ratios in Experiment 3.

[0058] Curvature radius ratio 1 1.1 1.2 1.25 1.3 1.4 1.5 1.75 2 2.5 2.75 3 Noise (db) 57.2 57.5 57.6 57.9 58.1 58.5 58.9 59.1 59.4 59.8 62.5 62.9 Heating speed (s) 228 227.6 227.2 222.1 221.2 220.9 220.5 219.5 218.7 218 217.2 216.7

[0059] A comprehensive analysis of the experimental data in Tables 1, 2, and 3 shows that when the radius r of the upper edge of the curved surface 2120 and the equivalent curvature radius R of the curved surface 2120 remain unchanged, the shape of the curved surface 2120 has very little effect on the noise and heating rate. However, when the radius r of the upper edge of the curved surface 2120 remains unchanged and the equivalent curvature radius R of the curved surface 2120 is changed, the noise and heating rate when boiling water in the electric kettle will change significantly.

[0060] As can be seen from Tables 2 and 3, as the equivalent curvature radius R of the curved surface 2120 gradually increases, the noise level when the electric kettle is boiling water increases. In particular, when the curvature radius R of the curved surface 2120 increases to more than 2.5 times the radius r of the upper edge of the curved surface, the noise level when the electric kettle is boiling water increases significantly. As the equivalent curvature radius R of the curved surface 2120 gradually decreases, the heating speed of the electric kettle gradually slows down, which is specifically reflected in the time required to heat water from 40°C to 90°C. The time is gradually prolonged, especially when the ratio of the equivalent curvature radius R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120 is reduced to 1.25, the water boiling speed of the electric kettle is significantly prolonged; when the ratio of the equivalent curvature radius R of the curved surface 2120 to the radius r of the upper edge of the curved surface 2120 is between 1.25 and 2.5, the electric kettle has lower noise and faster heating speed, can take into account both noise reduction and efficient heating, and provide users with a good water boiling experience.

[0061] In addition, the present application is particularly intended to solve the problem of achieving a good balance between high-speed heating and noise reduction for a high-power electric kettle when the power of the heating element 3 is not less than 1500W (watts) or the ratio of the power of the heating element 3 to the maximum water boiling capacity of the electric kettle is not less than 1000W / L (watts / liter). Of course, the technical solution of the present application is also applicable to electric kettles with a power of less than 1500W or a ratio of the power of the heating element 3 to the maximum water boiling capacity is less than 1000W / L. It can be understood that for an electric kettle with a maximum water level line, the maximum water boiling capacity of the electric kettle is the capacity calibrated by the maximum water level line of the electric kettle. For an electric kettle that can automatically fill water, the maximum water boiling capacity can be the maximum water boiling capacity preset by the machine or an optional maximum water boiling capacity.

[0062] The electric kettle of the present application has an outer shell 1 and an inner pot 2. The outer shell 1 includes a bottom shell covering the bottom 212 of the inner pot and a side shell surrounding the side of the inner pot 2. The bottom shell and the side shell can be formed as one piece or set separately. Specifically, the periphery of the bottom shell can extend to the side of the inner pot 2 and be connected to the lower edge of the side shell, or the lower edge of the side shell can extend to the bottom of the inner pot 2 and be connected to the periphery of the bottom shell, or the lower edge of the side shell can be vertically connected to the periphery of the bottom shell.

[0063] The shell 1 of the present application is wrapped around the outside of the inner liner 2. Specifically, there are the following schemes: Scheme 1: The upper edge of the shell 1 extends to the upper edge of the inner liner 2, and the inner liner 2 is completely placed in the space surrounded by the shell 1. The inner liner bottom 212 and the inner liner body 211 are completely wrapped by the shell 1. Such a setting of the electric kettle has a good heat preservation effect; Scheme 2: The upper edge of the shell 1 extends to between the upper edge of the inner liner bottom 212 and the upper edge of the inner liner body 211, that is, the shell 1 completely wraps the inner liner bottom 212 and partially wraps the inner liner body 211. With such a setting, the inner liner body 211 can be made of glass, and users can see from the inner liner body 211 that the inner liner bottom 212 is not covered. The portion covered by the outer shell 1 allows users to observe the boiling water, which improves the user experience. Option 3: The upper edge of the outer shell 1 extends to the upper edge of the inner pot bottom 212, that is, the outer shell 1 completely covers the inner pot bottom 212, and the inner pot body 211 is exposed. This provides a better visual experience than the electric kettle in Option 2. Option 4: The upper edge of the outer shell 1 extends to below the upper edge of the inner pot bottom 212, that is, the inner pot bottom 212 is partially covered by the outer shell 1, and the inner pot bottom 212 is placed in the space formed by the outer shell 1. The outer shell 1 covers the area above the heating element 3 of the inner pot bottom 212. This option also provides a good visual experience. Among them, the outer shell 1 of Options 1, 2, and 3 all completely covers the inner pot bottom 212, and the outer shell 1 of Option 4 partially covers the inner pot bottom 212.

[0064] In one embodiment of the present application, the inner liner 2 includes an inner liner body 21 and an aluminum heat conductor 22 attached to the outer wall of the inner liner body 21. The aluminum heat conductor 22 is welded to the bottom of the inner liner body 21, and the thermostat 4 and the heater 3 are both disposed on the aluminum heat conductor 22. The bottom of the inner liner body 21 and the aluminum heat conductor 22 together constitute the inner liner bottom 212, and the portion of the inner liner body 21 located above the inner liner bottom 212 constitutes the inner liner body 211.

[0065] Specifically, the inner liner body 21 is formed by stretching or die-casting of a stainless steel plate, the inner and outer surfaces of the inner liner body 21 are formed in a conformal manner, and the aluminum heat conductor 22 is formed in a conformal manner with the outer surface of the inner liner body 21, that is, the thickness of the inner liner body 21 is the same at all locations, the thickness of the aluminum heat conductor 22 is the same at all locations, and the aluminum heat conductor 22 is formed in a conformal manner with the outer surface of the inner liner body 21. The aluminum heat conductor 22 can completely include the bottom of the inner liner body 21, or the aluminum heat conductor 22 can completely wrap the bottom of the inner liner body 21. Providing a conformal aluminum heat conductor 22 on the outer surface of the inner liner body 21 can ensure a relatively uniform transfer of the heat generated by the heating element 3, thereby avoiding increased noise caused by heat concentration. In other embodiments of the present application, the inner liner body 21 can also be formed by stretching or die-casting a composite plate, the composite plate including an inner stainless steel layer and an outer aluminum layer, the stainless steel layer constituting the inner liner body 21, and the aluminum layer constituting the aluminum heat conductor 22.

[0066] Preferably, the inner liner body 211 includes a second inner liner body 2112 and a first inner liner body 2111 integrally formed with the upper edge of the curved surface 2120, and the first inner liner body 2111 and the second inner liner body 2112 are welded together. In this way, by providing a portion of the inner liner body 211 and the curved surface 2120 as an integrally formed structure, the connection method of the inner liner body 211 is simplified, the process difficulty is reduced, and it is conducive to industrial manufacturing.

[0067] In addition, the inner liner body 211 is preferably cylindrical, and the upper edge of the curved surface 2120 is tangentially connected to the lower edge of the inner liner body 211. The inner liner body 211 preferably adopts a cylindrical structure, such as a straight cylinder or a tapered cylinder (for example, a tapered cylinder with a larger bottom and a smaller top). This is convenient for the production of the inner liner body 211 and also facilitates the connection between the inner liner body 211 and the curved surface 2120. In particular, when the upper edge of the curved surface 2120 is tangentially connected to the lower edge of the inner liner body 211, a continuous shape is formed between the inner liner body 211 and the curved surface 2120, which makes it easier for consumers to clean after use, thereby improving the user experience.

[0068] In this application, a thermostat 4 is positioned in the middle of the outer surface of the inner liner bottom 212, and a heater 3 is positioned outside of the thermostat 4. To achieve precise temperature sensing, the temperature sensing element of the thermostat 4 is attached to the outer surface of the inner liner bottom 212. The heater 3 is an annular heating tube that surrounds and is fixed to the outer surface of the inner liner bottom 212. The heater 3 can be a C-shaped heating tube disposed around the inner liner bottom 212, or a multi-turn spiral heating tube disposed around the outer surface of the inner liner bottom 212.

[0069] Specifically, a point on the curved surface 2120 that is 1 / 2r away from the centerline of the inner liner bottom 212 is point S. A line connecting all the S points on the curved surface 2120 divides the curved surface 2120 into a central inner curved surface 2122 and a peripheral outer curved surface 2121. The heating element 3 is disposed on the outer surface of the inner liner bottom 212 corresponding to the outer curved surface 2121, and the thermostat 4 is disposed on the outer surface of the inner liner bottom 212 corresponding to the inner curved surface 2122. Because the temperature sensing element of the thermostat 4 needs to be in contact with the outer surface of the inner liner bottom 212 for temperature sensing, the outer surface of the inner liner bottom 212 corresponding to the inner curved surface 2122 has relatively gentle fluctuations relative to the horizontal plane, which facilitates the contact of the temperature sensing element. However, the outer curved surface 2121 has relatively steep fluctuations relative to the horizontal plane. The heating element 3 is disposed on the outer surface of the inner liner bottom 212 corresponding to the outer curved surface 2121. The temperature at the outer curved surface 2121 is higher, and bubbles are preferentially generated on the outer curved surface 2121, which facilitates bubble aggregation and further reduces noise.

[0070] Moreover, since the outer surface of the inner liner 2 will dissipate heat outward, the water temperature in the side wall area of ​​the inner liner 2 will be lower than the water temperature in the middle area of ​​the inner liner 2. Setting the heating element 3 on the outside of the inner liner bottom 212 corresponding to the outer arc surface 2121 can effectively increase the water temperature in the side wall area of ​​the inner liner 2, weaken convection, and thereby reduce the detachment of bubbles, thereby further achieving the technical effect of noise reduction.

[0071] In this application, the angle between the tangent line at the edge of the inner curved surface 2122 and the horizontal plane is A, where A is ≤ 30°. This configuration prevents the outer wall of the inner liner 2, corresponding to the inner curved surface 2122, from being too steep to affect the installation of the temperature sensing element of the thermostat 4, thereby balancing the user experience with manufacturing difficulty. It should be understood that the tangent line at the edge of the inner curved surface 2122 refers to the tangent line of the generatrix of the inner curved surface 2122 at its upper edge.

[0072] The height h1 of the inner curved surface 2122 is preferably controlled to be no greater than 5mm. The undulations of the inner curved surface 2122 are not excessive, and the undulations of the outer wall of the inner pot 2 corresponding to the inner curved surface 2122 are even smaller, ensuring that the temperature sensing element of the thermostat 4 can be securely installed. The height h2 of the outer curved surface 2121 is preferably no less than 7mm. The outer curved surface 2121 has a certain degree of steepness, so that bubbles generated on the outer curved surface 2121 can easily slide along the surface of the outer curved surface 2121 and merge into large bubbles, ensuring that the electric kettle can effectively reduce noise when boiling water. Moreover, if the outer curved surface 2121 is too short, the heating element 3 mounted on the outer curved surface 2121 will easily protrude from the lower surface of the outer wall of the inner pot 2, occupying excessive installation space and hindering the effective use of space.

[0073] The radius of curvature of the inner arc surface 2122 is preferably greater than the radius of curvature of the outer arc surface 2121. The radius of curvature of the inner arc surface 2122 is greater than the radius of curvature of the outer arc surface 2121. The inner arc surface 2122 is flatter than the outer arc surface 2121, and the outer arc surface 2121 is steeper than the inner arc surface 2122. The heating element 3 is arranged on the outer wall of the inner liner 2 corresponding to the outer arc surface 2121. Large bubbles are more likely to accumulate on the outer arc surface 2121, and the noise reduction effect is more significant. It can be understood that the radius of curvature of the inner arc surface 2122 is greater than the radius of curvature of the outer arc surface 2121, which means that the radius of curvature of any arc section on the busbar of the inner arc surface 2122 is greater than the radius of curvature of any arc section on the busbar of the outer arc surface 2121. Preferably, the radius of curvature of the entire curved surface 2120 gradually decreases from bottom to top.

[0074] It is understood that the electric kettle of the present application can be an electric kettle with an integrated kettle body and base, or an electric kettle with a separate kettle body and base. In the case of a separate electric kettle, the inner pot 2, outer shell 1, heating element 3 and other components are arranged on the kettle body. The electric kettle of the present application is an electric kettle in a broad sense. In addition to having the function of boiling water, it can also heat beverages.

[0075] It can be understood that the inner bottom 212 and the inner body 211 of the electric kettle of the present application can be formed by stretching or stamping a metal plate as a whole, or can be formed by stretching or stamping different metal plates and then welding them together, or can be formed by connecting the inner bottom 212 formed by stretching or stamping a metal plate and the inner body 211 formed by glass.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the present invention are covered by the scope of the claims of the present invention and will not be listed one by one here.

Claims

1. An electric kettle having an outer shell and an inner liner for holding liquid, characterized in that: The inner liner includes an inner liner bottom and an inner liner body extending from the upper edge of the inner liner bottom to the inner liner opening. A temperature controller is provided in the middle of the outer surface of the inner liner bottom, and a heating element is provided on the outer surface of the inner liner bottom on the outside of the temperature controller. The inner surface of the inner liner bottom is an outwardly convex arc surface tangent to the horizontal plane. The width of the arc surface gradually increases from bottom to top. The radius of the upper edge of the arc surface is r, and the equivalent curvature radius of the arc surface is R, wherein 1.25≤R / r≤2.

5.

2. The electric kettle according to claim 1, characterized in that: The point on the arc surface that is at a horizontal distance of 1 / 2r from the center line of the bottom of the inner pot is point S, and the line connecting point S divides the arc surface into a central inner arc surface and a peripheral outer arc surface. The inner pot is provided with a temperature controller on the outer side corresponding to the inner arc surface, and the inner pot is provided with a heating element on the outer side corresponding to the outer arc surface.

3. The electric kettle according to claim 2, characterized in that: The included angle between the tangent line of the edge of the inner arc surface and the horizontal plane is A, and A≤30°.

4. The electric kettle according to claim 2, characterized in that: The height of the inner arc surface is h1, and h1≤5mm.

5. The electric kettle according to claim 2, characterized in that: The height of the outer arc surface is h2, and h2≥7mm.

6. The electric kettle according to claim 2, characterized in that: The curvature radius of the inner arc surface is greater than the curvature radius of the outer arc surface.

7. An electric kettle according to any one of claims 1 to 6, characterized in that: The inner surface and outer surface of the inner container bottom are arranged in a conformal manner.

8. The electric kettle according to claim 1, characterized in that: The inner container body is cylindrical, and the upper edge of the arc surface is tangent to the lower edge of the inner container body.

9. The electric kettle according to claim 8, characterized in that: The inner liner body includes a second inner liner body and a first inner liner body integrally formed with the upper edge of the arc-shaped surface, and the first inner liner body and the second inner liner body are connected by welding.

10. The electric kettle according to claim 1, characterized in that: The power of the heating element is not less than 1500W; or, the ratio of the power of the heating element to the maximum water boiling capacity of the electric kettle is not less than 1000W / L.

Images