Electric kettle

Abstract

The utility model provides an electric kettle, which relates to an electric kettle and comprises a metal bottom plate, and a heating element and a temperature sensing element arranged on the inner side of the heating element are arranged on the outer wall of the metal bottom plate in a surrounding manner. The inner wall of the metal bottom plate is covered with a metal hydrophobic film in the corresponding area of the inner side of the outer end of the heating element, lines are carved on the metal hydrophobic film to form a carved area, the heating element is completely covered with the carved area, and the equivalent radius R from the inner edge of the heating element to the center of the metal bottom plate is larger than or equal to 1. And the equivalent radius from the inner edge of the carving area to the center of the metal bottom plate is not less than 0.55 R. According to the electric kettle, the technical problem that in the prior art, laser engraving and other treatment are carried out on the whole metal hydrophobic film, so that the noise reduction effect and the non-viscosity performance are reduced is solved under the condition that the early jumping prevention performance is not affected.

Description

Technical Field

[0001] The utility model relates to the technical field of electric kettles, in particular to an electric kettle. Background Art

[0002] Electric kettles may include health kettles, electric thermoses and common electric kettles.

[0003] The electric kettle heats the water in the kettle through a heating tube. The steam generated when the water boils deforms the bimetallic strip of the steam temperature sensing element. This deformation pushes the power switch to cut off the power through the lever principle, thereby boiling the water.

[0004] The health kettle can boil water through a heating element, which is controlled by a temperature sensor or other temperature-sensing element. Besides boiling water, the health kettle can also be used to make scented tea, fruit tea, and soup.

[0005] As people continue to pursue faster water boiling speeds, the heating power of electric kettles continues to increase. While speeding up the boiling process, it also increases the noise level. Therefore, reducing the noise level without reducing the power level has become a research and development goal.

[0006] Early solutions have included shock absorbers in electric kettles to reduce vibration caused by bubbles bursting, thereby reducing noise during boiling. For example, patent CN201220529633.8 describes an electric kettle with a sound-damping ring on the heating plate. This ring prevents bubbles from rising from the heating plate from hitting the ring, preventing them from rushing towards the water surface. However, it has been found that placing the sound-damping ring inside the inner heating liner can cause repeated heating during multiple boiling cycles. This repeated heating process can cause harmful substances to continuously precipitate from the ring, impacting user safety. Furthermore, a gap between the ring and the inner wall of the inner heating liner can easily form, allowing foreign matter such as scale to enter, affecting the aesthetics of the inner liner and increasing the difficulty of cleaning. The main source of noise during boiling is the bursting of bubbles within the inner liner, particularly on the heating base. Placing the sound-damping ring between the kettle body and the base reduces the quieting effect.

[0007] As people's understanding of the principle of boiling water noise has improved, they have gradually begun to change the heating base of the inner tank, which directly affects the generation and convergence of bubbles.

[0008] One of the ideas is to change the contact angle between the bubbles and the heating base. For example, the electric kettle provided by patent CN201710057447.6 sets the contact surface between the heating tube and the heating base to an inclined surface or a curved surface, so that the buoyancy of the bubbles and the viscosity of the slope surface are used to make the bubbles slide from bottom to top along the slope surface, thereby making the small bubbles on the slope surface merge into large bubbles, reducing the small bubbles from breaking off from the bottom wall of the kettle into the water, and large bubbles are more difficult to break in the water after breaking off from the bottom wall of the kettle, thereby solving the problem of small and dense local bubbles and achieving a noise reduction effect. This idea requires changes to the main structure of the heating base, which will bring about changes in structures such as the heating tube. The average price of commercially available electric kettles is generally between 69 and 99. Changes to the main structure of the heating base and the heating tube will have a greater impact on the selling price of the electric kettle.

[0009] Another idea is to change the microstructure of the heating base plate. For example, patent CN201921629511.4 provides a noise-reducing electric kettle. The surface of the stainless steel material layer is formed with concave holes by laser etching. The concave holes increase the contact area between the surface of the heat-collecting area and the water, accelerate the heat convection of water vapor on the surface of the heat-collecting area, reduce the number of bubbles generated, and effectively reduce the generation of noise. The concave holes can also facilitate the aggregation of bubbles. A small amount of small bubbles are more likely to gather on the surface of the concave holes, forming larger bubbles and drifting away from the bottom before bursting. The aperture of the concave holes in this structure is 0.3mm-1.5mm, and the depth of the concave holes is 0.05mm-0.2mm. The aperture and depth of the concave holes are limited, so the effect of increasing the contact area between the surface of the heat-collecting area and the water is also limited. It can only accommodate bubbles with a diameter of less than 1.5mm. If the aperture and depth of the concave holes are increased, scale or other foreign matter may enter the concave holes, affecting the contact area between the water in the concave holes and the surface of the heat-collecting area.

[0010] Another approach involves applying a hydrophobic coating to the heating base plate to promote the merging of bubbles into larger ones. For example, patent CN200720009531.2 discloses an electric water heater comprising an element plate having an upper side and a lower side, the upper side being in contact with water and the lower side having an electric heating element in thermal contact therewith. The upper side is coated and / or treated to reduce noise. The container further comprises a noise suppressor disposed above, adjacent to, and extending substantially over the electric heating element. The suppressor comprises a surface that converges or diverges in an upward direction. This patent utilizes a coating on the element plate to encourage small bubbles on the element plate to converge into larger ones. However, the patent's specification states that after 15 cycles of boiling water, the noise level of the electric water heater increases, and the noise becomes sharp. This requires the installation of an additional suppressor on the element plate. The suppressor acts as a guide and converges bubbles, reducing localized boiling at the heater. Installing a suppressor within an electric kettle is not compatible with consumer usage habits. Furthermore, the suppressor needs to be manufactured separately, impacting the cost of the kettle.

[0011] At the same time, prior art also mentions that applying a hydrophobic coating to the heating baseplate causes small bubbles to coalesce into larger ones. In particular, bubbles often form in the projection area of ​​the heating element on the heating baseplate. Heat from the heating element to the heating baseplate cannot be transferred to the temperature sensing element, which can easily lead to premature tripping. To address the premature tripping problem, the aforementioned patent CN200720009531.2 applies a coating locally to the heating baseplate in the areas corresponding to the heating element and the temperature sensing element.

[0012] With the development of the times, in order to improve the user experience of electric kettles and solve technical problems such as scale deposition and burning of the bottom during cooking, electric kettles have to be equipped with a hydrophobic coating on the heating base. At this time, it is crucial to solve the problem of premature tripping caused by hydrophobic coating.

[0013] The prior art has proposed patent CN202221959466.0, which provides a boiling water kettle. The inner bottom surface of the inner pot described in the patent is also provided with a noise reduction interval formed by laser engraving after the hydrophobic coating is sprayed and formed. The noise reduction interval divides the hydrophobic coating into a plurality of mutually separated polygonal structures, and at least two polygonal structures overlap with the projection of the temperature sensing area on the inner bottom surface of the inner pot. The polygonal structure limits the size of the bubbles, so that the bubbles can burst in time, and the heat can be transferred to the thermostat in time to prevent the occurrence of premature tripping. In actual use, it was found that the polygonal structure described in the patent covers the entire surface of the heating bottom, which affects the noise reduction performance of the electric kettle. At the same time, the polygonal structure covers a large area, and the heating bottom plate is covered with grooves, which also affects the anti-sticking performance.

[0014] In actual use, it is also found that water kettles often use hydrophobic coatings such as chemical coatings. Under high temperature and dry burning conditions, the chemical coating is more likely to fall off, affecting its anti-stick effect and also causing certain impacts on human health.

[0015] Prior art CN202320452914.6, this patent proposes a non-stick pan, which uses a physical vapor deposition (PVD) process to form a metal protective film (equivalent to the metal hydrophobic film of this application) on the pan. It uses physical methods (such as sputtering, etc.) to vaporize the coating material and deposit it into a film on the surface of the substrate.

[0016] Specifically, during the PVD process, plasma argon (Ar+) ions and electrons bombard the target material, such as chromium (Cr), to sputter out small molecular clusters of target material onto the surface of the cookware substrate (inner stainless steel layer). Because the substrate surface and the molecular clusters are highly bonded and close to the metal bond energy, this metal protective layer is difficult to separate. In addition, the Vickers hardness of the Cr layer surface is relatively high, which can reach several times the Vickers hardness of the substrate, and the surface density is very good, with ultra-high wear resistance and scratch resistance, which can play a role in maintaining a long-lasting non-stick effect. In addition, the formed Cr layer is relatively stable and will not react after high temperature, and there will be no blueing phenomenon similar to the stainless steel surface, which improves the user experience. The Cr layer can be a CrFeNi alloy layer and a CrFe alloy layer from the inside to the outside.

[0017] Metal protective film can reduce the surface energy of the metal surface, making the contact area of ​​pollutants smaller, the force weaker, and not easily wetted by water. When water droplets roll on the surface, the pollutants are easily carried away, giving it certain self-cleaning properties.

[0018] The target material can also be made of titanium, zinc metal, nickel metal, etc. Titanium also has high hardness, good friction resistance, and certain antibacterial properties, which is beneficial to improving the hygiene of the pot. Utility Model Content

[0019] The purpose of the utility model is to provide an electric kettle with a metal bottom plate provided with a metal hydrophobic film, which solves the technical problem that the existing technology performs laser engraving and other treatments on the entire metal hydrophobic film, thereby reducing the noise reduction effect and non-stick performance without affecting the anti-premature tripping performance.

[0020] The embodiment of the present utility model is achieved as follows:

[0021] An embodiment of the present application provides an electric kettle, comprising a metal bottom plate, wherein an outer wall of the metal bottom plate is surrounded by a heating element and a temperature sensing element provided inside the heating element;

[0022] The inner wall of the metal bottom plate is covered with a metal hydrophobic film in the corresponding area inside the outer end of the heating element.

[0023] The metal hydrophobic film is engraved with lines to form an engraved area, and the heating element is completely covered by the engraved area.

[0024] The equivalent radius R from the inner edge of the heating element to the center of the metal base plate and the equivalent radius from the inner edge of the engraving area to the center of the metal base plate are not less than 0.55R.

[0025] In some embodiments of the present invention, the equivalent radius from the inner edge of the engraving area to the center of the metal base plate is smaller than R.

[0026] In some embodiments of the present invention, the engraving area is formed by arranging a plurality of closed circles, and the equivalent diameter of the closed circles is smaller than half of the radial coverage width of the heating element.

[0027] In some embodiments of the present invention, the engraving area is formed by arranging a plurality of closed circles with different equivalent diameters.

[0028] In some embodiments of the present invention, the closed circle is a circle.

[0029] In some embodiments of the present invention, the equivalent outer diameter of the engraving area is larger than the equivalent outer diameter of the heating element, and the equivalent outer diameter of the engraving area is smaller than the equivalent outer diameter of the metal base plate.

[0030] In some embodiments of the present invention, the equivalent outer diameter of the metal hydrophobic film is larger than the equivalent outer diameter of the engraving area.

[0031] In some embodiments of the present invention, the heating element is a non-enclosed heating tube having an opening, and the engraving area covers a connecting line segment of the opening.

[0032] In some embodiments of the present invention, the heating element is a non-enclosed heating tube having an opening, and the temperature sensing area of ​​the temperature sensing element is located on a side facing the opening.

[0033] In some embodiments of the present invention, the metal base plate includes a transversely extending base plate, and the heating element is arranged on the inner side of the outer edge of the base plate; or, the bottom of the metal base plate includes an arc-shaped portion, and the heating element is arranged on the outer wall of the arc-shaped portion.

[0034] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0035] This embodiment features an engraved area and an area not covered by the engraved area (hereinafter referred to as the non-engraved area). Because the engraved area completely covers the heating element, the non-engraved area is farther away from the heating element, resulting in fewer bubbles. Consequently, no pattern engraving occurs away from the heating element, encouraging small bubbles in the non-engraved area to migrate and aggregate, further reducing boiling noise. Furthermore, because the non-engraved area generates fewer bubbles, there's no need to worry about excessive bubbles forming an air film. This improves the kettle's noise reduction performance compared to existing technologies.

[0036] Because the temperature sensing element is located inside the heating element (the side of the heating element's geometric center can be considered the inside), the inner edge of the engraved area can be wider than the inner edge of the heating element to prevent bubbles from accidentally forming an air film inside the heating element, thereby ensuring the kettle's ability to prevent premature tripping. Furthermore, because the engraved area in this embodiment is smaller than in the prior art, the kettle's ability to prevent the bottom of the kettle from becoming burnt is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the positional relationship among the metal base plate, metal hydrophobic membrane, sealing ring, temperature sensing element and heating element in the present invention;

[0038] Figure 2 It is a structural diagram of the engraving area and the closed circle in the utility model;

[0039] Figure 3 This is a schematic diagram of the structure of the position in which the engraving area is wider than the heating element in the present invention;

[0040] Figure 4 This is a noise comparison table of the electric kettle with and without the metal hydrophobic film and with and without the engraved area of ​​the utility model;

[0041] Figure 5 A statistical table of the inner diameter of the engraving area, the area of ​​the engraving area, the residual volume and the noise of the utility model;

[0042] Figure 6 This is a comparison diagram of the relationship between the engraving area and noise in the utility model;

[0043] Figure 7 This is a comparison diagram of the closed loop types and noise in this utility model.

[0044] Icon: 1-metal base plate, 2-metal hydrophobic film, 3-engraving area, 301-sealing circle, 4-temperature sensing element, 5-heating element. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] Example 1

[0047] like Figure 1-7 As shown, this embodiment provides an electric kettle, comprising a metal bottom plate 1, wherein the outer wall of the metal bottom plate 1 is surrounded by a heating element 5 and a temperature sensing element 4 provided inside the heating element 5;

[0048] The inner wall of the metal bottom plate 1 is covered with a metal hydrophobic film 2 in the area corresponding to the inner side of the outer end of the heating element 5.

[0049] The metal hydrophobic film 2 is engraved with lines to form an engraved area 3, and the heating element 5 is completely covered by the engraved area 3.

[0050] The equivalent radius R from the inner edge of the heating element 5 to the center of the metal base plate 1 and the equivalent radius from the inner edge of the engraving area 3 to the center of the metal base plate 1 are not less than 0.55R.

[0051] In this embodiment, the metal base plate 1 can be used to support the liquid and transfer heat to the liquid. The contact surface between the base plate and the liquid can be the inner wall of the metal base plate 1, and the part of the metal base plate 1 facing away from the inner wall can be the outer wall of the metal base plate 1. The bottom of the heating element 5 and the temperature sensing element 4 in contact with the metal base plate 1 is at least made of metal. Under the action of the plasma electric field, the evaporated material or its reaction products of the target material (such as chromium, other metals and alloys, etc.) are deposited on the surface of the metal base plate 1, repairing the original unevenness of the inner wall of the metal base plate 1 and forming a smoother metal hydrophobic film 2 on the inner wall of the metal base plate 1. Compared with the prior art, this embodiment does not use conventional chemical coatings, but instead provides a metal hydrophobic film 2 in the electric kettle, making the inner wall of the metal base plate 1 smoother, increasing the flow rate of the water on the surface of the inner wall of the metal base plate 1 during the boiling process, and reducing the retention of water on the surface of the inner wall of the metal base plate 1.

[0052] In actual use, the surface roughness of the inner wall of the metal bottom plate 1 that has only been polished is about 0.089 μm under microstructure measurement. The surface roughness of the inner wall of the metal bottom plate 1 that has been repaired through ionization impact treatment is about 0.052 μm.

[0053] During use, users often have the need to use electric kettles for cooking, such as porridge. The surface of existing electric kettles is relatively rough, and larger foods (such as rice grains) are easy to stay on the metal bottom plate 1, which is often easy to get stuck when cooking porridge. Even if some users do not have cooking needs, during long-term use of the electric kettle, scale will be deposited on the inner wall of the metal bottom plate 1, especially on the longitudinal projection area of ​​the heating element 5 on the inner wall of the metal bottom plate 1 (hereinafter referred to as the area corresponding to the heating element 5 on the inner wall of the metal bottom plate 1), affecting the user's experience. In this embodiment, the inner wall of the metal bottom plate 1, especially the area corresponding to the heating element 5 on the inner wall of the metal bottom plate 1, is covered with a metal hydrophobic film 2. The metal hydrophobic film 2 makes the inner wall of the metal bottom plate 1 smoother, reduces the time that water, food or metal stays, and prevents food from sticking to the metal bottom plate 1, thereby reducing the occurrence of sticking and reducing the deposition of scale on the metal bottom plate 1.

[0054] When heating water, the existing heating element 5 often generates a heating power exceeding 800W. This results in the heating element 5 generating a large number of small bubbles in the corresponding area on the inner wall of the metal base plate 1 during the heating process (especially when heating from 65°C to 95°C). Some of these small bubbles burst on the inner wall of the metal base plate 1, generating a significant amount of noise. The inner wall of the metal base plate 1 is covered with a metal hydrophobic film 2 in the area inside the outer end of the heating element 5. Due to the vibration of the bursting bubbles and the high surface velocity of the inner wall of the metal base plate 1, the small bubbles slide and merge on the inner wall of the metal base plate 1 to form larger bubbles. This reduces the number of bursting bubbles and thus reduces the noise during heating.

[0055] like Figure 4 As described above, in the test environment of 1.5L water, 1000W heating power, and closed lid test, the noise of the electric kettle without the metal hydrophobic film 2 is the highest, which is 59.89dB; the electric kettle with the metal hydrophobic film 2 provided with the engraving area 3 has the lowest noise, which is 37.3dB. The maximum noise difference between the two different electric kettles is more than 21 times.

[0056] At the same time, the metal hydrophobic film 2 promotes the convergence of small bubbles. As time goes by, large bubbles will gradually form a whole large air film. The formed air film isolates the water from the heating element 5 in the corresponding area of ​​the inner wall of the metal base plate 1, resulting in the heat generated by the heating element 5 cannot be conducted to the water, thereby forming local dry burning, causing the temperature at the thermostat to rise sharply to its protection temperature, the electric kettle to lose power, and the water does not boil completely (hereinafter referred to as premature jump).

[0057] In the prior art, a suppressor is installed in the inner pot to guide bubbles to the upper side of the inner pot and prevent bubbles from accumulating at the bottom of the inner pot, thereby reducing premature tripping of the electric kettle. However, installing a suppressor in the inner pot does not conform to user habits and hinders users from using the electric kettle to cook food, affecting normal use.

[0058] In this embodiment, the metal hydrophobic film 2 is engraved with lines to form an engraved area 3 , and the heating element 5 is completely covered by the engraved area 3 .

[0059] The lines in the engraving area 3 destroy the metal hydrophobic film 2 and change the microstructure of the metal hydrophobic film 2. The metal hydrophobic film 2 is not completely continuous in the engraving area 3. When the bubbles slide on the metal hydrophobic film 2, they will be blocked by the lines, which prevents the bubbles from sliding too long and controls the speed at which small bubbles converge into large bubbles. At the same time, in the process of small bubbles converging, the contact edge between the large bubbles and the metal hydrophobic film 2 gradually expands. When the contact edge of the large bubble touches the lines in the engraving area 3, the lines in the engraving area 3 will prevent the contact edge of the large bubble from continuing to expand. This embodiment prevents small bubbles from moving quickly and gathering into large bubbles during the water boiling process, and also prevents the size of large bubbles from continuously expanding into an air film. There is no need to set up additional component structures such as suppressors, and local dry burning is prevented from causing the temperature sensing element 4 to trip prematurely without affecting the user's use.

[0060] Some existing technologies address the premature tripping problem of electric kettles covered with hydrophobic membranes by uniformly disposing polygonal structures on the bottom of the inner pot, particularly where the polygonal structures cover the area where the temperature sensor 4 is located. However, existing technologies require laser cutting of the entire bottom of the inner pot, which affects the kettle's ability to prevent the bottom from burning.

[0061] In this embodiment, the equivalent radius R from the inner edge of the heating element 5 to the center of the metal base plate 1 and the equivalent radius from the inner edge of the engraving area 3 to the center of the metal base plate 1 are not less than 0.55R.

[0062] This embodiment adopts a technical approach that is completely different from the existing technology. By setting the coverage range and uncovered range of the engraving area 3, the noise reduction performance is further improved while ensuring the performance of preventing the bottom of the electric kettle from being burnt and preventing premature tripping.

[0063] When in use, the heat of the heating element 5 is transferred from the outer wall of the metal base plate 1 to the inner wall of the metal base plate 1. The heat transfer process includes transfer along the thickness of the metal base plate 1 and transfer along the extension direction of the metal base plate 1, so that the width of the area where the inner wall of the metal base plate 1 is affected by the heat transfer of the heating element 5 can be slightly larger than the width of the heating element 5.

[0064] In particular, compared to existing technologies, this embodiment features an engraved area 3 and an area not covered by the engraved area 3 (hereinafter referred to as the non-engraved area). Because the engraved area 3 completely covers the heating element 5, the non-engraved area is farther away from the heating element 5, resulting in fewer bubbles. Consequently, no pattern engraving occurs away from the heating element 5, encouraging small bubbles in the non-engraved area to migrate and aggregate, further reducing boiling noise. Furthermore, because the non-engraved area generates fewer bubbles, there's no need to worry about excessive bubbles forming an air film. This improves the kettle's noise reduction performance compared to existing technologies.

[0065] Because the temperature sensing element 4 is located inside the heating element 5 (the side on the geometric center of the heating element 5 can be considered the inside), the inner edge of the engraved area 3 can be wider than the inner edge of the heating element 5 to prevent bubbles from accidentally forming an air film inside the heating element 5, thereby ensuring the kettle's ability to prevent premature tripping. Furthermore, because the area of ​​the engraved area 3 in this embodiment is smaller than that of the prior art, the kettle's ability to prevent the bottom of the kettle from becoming burnt is further ensured.

[0066] In some implementations, such as Figure 5 and Figure 6 As shown, the outer diameter of the heating tube is 80 mm, the inner diameter of the heating tube is 68 mm, and the heating power of the heating tube is 1000 W; the outer diameter of the engraving area 3 is D=90 mm; the initial inner diameter of the engraving area 3 is D0=58 mm, and the inner diameter of the engraving area 3 can be continuously moved toward the center by 10 mm in different implementation methods; when the metal hydrophobic film 2 is not engraved, the inner diameter of the engraving area 3 is D0=90 mm, the area of ​​the engraving area 3 is S=0, and the area calculation formula of the engraving area 3 is S=π(D2-(D0)2) / 4.

[0067] like Figure 5 and Figure 6 As shown, the area of ​​the engraving area 3 is proportional to the non-stickiness. The smaller the area of ​​the engraving area 3, the better the non-stickiness.

[0068] As the area of ​​engraving zone 3 gradually increases, the noise level decreases from high to low (1184mm). 2 In order to achieve a better noise reduction effect and take into account the non-stickiness and anti-early jump performance, the equivalent radius from the inner edge of the engraving area 3 to the center of the metal base plate 1 in this embodiment is not less than 0.55R.

[0069] In some embodiments, the engraving area 3 may be annular, and the center of the engraving area 3 overlaps with the center of the metal base plate 1 in the longitudinal direction.

[0070] In some embodiments, the heating element 5 may be connected to the temperature sensing element 4. When the temperature sensing element 4 senses that the temperature is higher than the set temperature, the temperature sensing element 4 controls the heating element 5 to stop working to prevent damage to the electric kettle.

[0071] In some embodiments, a glass sidewall may be provided on the outer periphery of the metal base plate 1 .

[0072] In some embodiments, the single-ring heating element 5 may be a C-shaped heating tube or a single-ring annular heating tube. When the heating element 5 is a ring-shaped heating element 5 , the equivalent radius of the heating element 5 is equal to the radius of the heating element 5 .

[0073] When the heating element 5 is an elliptical ring or other non-circular shape, the equivalent diameter can be calculated.

[0074] The calculation formula of the equivalent diameter De can be: De=square root of (A / π), where A represents the area enclosed by the edge, and π represents pi.

[0075] When it is necessary to calculate the equivalent radius of a C-type heating tube, since the C-type heating tube has an opening, the C-type heating tube can be regarded as a closed figure connected by the openings during the calculation, thereby facilitating the calculation of the equivalent radius of the C-type heating tube.

[0076] In some embodiments, the heating element 5 may be a multi-convolution heating element 5 , thereby increasing the contact area between the heating element 5 and the metal base plate 1 . While maintaining the same heating power, this reduces the heat load per unit area of ​​the metal base plate 1 , further reducing the noise level of the kettle. A multi-convolution heating element 5 may increase the overall width of the heating element 5 , bringing the edge of the heating element 5 closer to the temperature sensing element 4 . To prevent bubbles from forming an air film near the temperature sensing element 4 , the extent of the engraving area 3 extending toward the temperature sensing element 4 may be increased.

[0077] In some embodiments, when the heating element 5 is a multi-ring heating element 5 , the equivalent radius R from the inner edge of the heating element 5 to the center of the metal base plate 1 , wherein the inner edge of the heating element 5 may specifically be the inner edge of the heating element 5 closest to the temperature sensing element 4 .

[0078] In the prior art, electric kettles have relatively high power, often with heating power greater than 800W. The heat generated by the heating element 5 is transmitted along the extension direction of the metal base plate 1. If the inner edge of the engraving area 3 and the inner edge of the heating element 5 are located on a vertical plane, a large number of bubbles will be generated in the non-engraving area 3 and gathered into an air film, which may still cause the electric kettle to trip prematurely.

[0079] Among them, the heating element 5 can be in an elliptical shape or other shapes, and the temperature sensing element 4 can also be offset on the metal base plate 1, resulting in a large difference between the shortest distance and the farthest distance between the heating element 5 and the temperature sensing element 4. At this time, if the edge of the engraving area 3 is flush with the inner edge of the heating element 5, the bubbles on the inner edge of the heating element 5 are too large, which may still cause the electric kettle to trip prematurely.

[0080] In some implementations of this embodiment, the equivalent radius from the inner edge of the engraving area 3 to the center of the metal base plate 1 is smaller than R.

[0081] In the above embodiment, in order to prevent the bubbles inside the heating element 5 from accidentally gathering into an air film, the engraving area 3 needs to continue to extend inward along the inner side to prevent the generation of an air film due to the high power of the heating element 5; and when the heating element 5 is close to the temperature sensing element 4, the size of the bubbles on the inner edge of the heating element 5 is controlled.

[0082] Specifically, for an electric kettle with a heating power of 1000W and a capacity of 1.5L, the inner diameter of the heating tube may be 68mm, and the equivalent diameter of the inner edge of the engraving area 3 may be 58mm.

[0083] In some implementations of this embodiment, the engraving area 3 is formed by arranging a plurality of closed circles 301 , and the equivalent diameter of the closed circles 301 is smaller than half of the radial coverage width of the heating element 5 .

[0084] In the above embodiment, the closed ring 301 can be carved with annular patterns. When boiling water, bubbles can be generated in the closed ring 301. Since the patterns of the closed ring 301 restrict the movement of bubbles, the size of the bubbles in the closed ring 301 depends on the size of the closed ring 301.

[0085] To prevent excessive bubbles from causing localized dry-boiling and premature tripping, this embodiment limits the equivalent diameter of the closed loop 301 to less than the width of the heating element 5. Preferably, the equivalent diameter of the closed loop 301 is less than half the width of the heating element 5. That is, multiple closed loops 301 overlap with the projection of the heating element 5 on the metal base plate 1, and the closed loops 301 are relatively small. The process of bubbles gradually growing larger and eventually bursting or detaching is relatively short. When the heating element 5 is provided with multiple smaller closed loops 301, while some of the bubbles in the closed loops 301 are in the process of growing larger, bursting, and detaching, the remaining closed loops 301 can still contact and transfer heat with the water, reducing the probability of the electric kettle drying out and premature tripping.

[0086] The engraving area 3 may adopt a closed circle 301 in a circular, rectangular, or triangular shape. The engraving area 3 may adopt a closed circle 301 in one shape or multiple shapes.

[0087] The equivalent diameter De of the engraving area 3 can be calculated according to the formula: De=square root of (A / π), where A represents the area enclosed by the edge and π represents pi.

[0088] Among them, adjacent closed circles 301 in the engraving area 3 can be arranged in a collinear manner (enclosed circles 301 with straight edges such as rectangles or triangles), and adjacent closed circles 301 in the engraving area 3 can also be arranged tangentially (enclosed circles 301 with arc edges such as circles or ellipses).

[0089] The closed circles 301 in the engraving area 3 may also be evenly distributed, specifically, the centroids of the closed circles 301 are distributed at the same horizontal and vertical distances.

[0090] The sealing ring 301 can be formed by laser engraving. The depth of the lines of the sealing ring 301 is h, 0.4 μm>h. The width of the lines of the sealing ring 301 is w, 0.37 mm ≥ w ≥ 0.15 mm.

[0091] In some implementations of this embodiment, the engraving area 3 is formed by arranging a plurality of closed circles 301 with different equivalent diameters.

[0092] In the prior art, to limit the maximum size of bubbles generated, closed lines of identical size and shape are often engraved. However, during use, it was found that because the engravings were identical in size and shape (especially the same size), the maximum size of the generated bubbles was consistent. Because the maximum bubble size is consistent, the time it takes for bubbles to grow, fall off, or burst is relatively consistent, which can easily cause a large number of bubbles to burst at a similar rhythm, thereby increasing noise. Although the time it takes for bubbles to grow, fall off, or burst is relatively short, the number of bubbles generated when boiling water is large, and the noise generated by similar bubbles bursting is at a similar sound wave frequency, which may make the noise more noticeable to users.

[0093] In some embodiments, the sizes of the closed ring 301 vary, resulting in different maximum sizes of bubbles generated within the closed ring 301. Small bubbles converge into bubbles of varying sizes, yet still reduce the total number of bubbles that burst. By interfering with the maximum size of the bubbles, the time it takes for them to grow, fall off, or burst is affected, preventing a large number of bubbles from bursting at a similar rhythm or simultaneously, reducing potential resonance and improving the noise performance of the electric kettle. Furthermore, by interfering with the maximum size of the bubbles, the frequency of the sound waves generated when the bubbles burst is altered, preventing a large number of bubbles from emitting the same or similar sound frequencies, further improving the user's hearing experience.

[0094] Compared to the polygonal structures of the same area and shape in the prior art, the pattern in this embodiment comprises multiple groups of closed circles 301 with different areas, each with a different maximum bubble size. In actual use, it has been found that large bubbles can affect the cavitation effect of small bubbles. Large bubbles can suppress the vibration of small bubbles or cause delayed expansion, thereby reducing the noise of the kettle.

[0095] The polygonal structures in the prior art have the same area and shape, resulting in the production of mostly large bubbles. The larger the bubble, the higher the energy required to rupture. When a large number of large bubbles rupture at a similar frequency, the higher energy easily causes other bubbles to rupture simultaneously. In this embodiment, the pattern includes multiple groups of closed circles 301 with varying areas, making it difficult for bubbles of varying sizes and energies to rupture simultaneously in large numbers, thus reducing the likelihood of simultaneous rupture. Furthermore, in this embodiment, the energy generated by small bubbles after rupture is relatively low, and the resulting vibrations are unlikely to rupture other bubbles. Instead, these vibrations can cause other bubbles to detach from the surface of the metal base plate 1, further reducing noise.

[0096] In the existing technology, people tend to tend to carve regular hexagonal shapes, but the attachment surface between the bubbles and the metal base plate 1 tends to be circular. The regular hexagonal patterns and the bubbles are often in point contact, and the regular hexagonal patterns have a poor effect on restricting the bubbles. The bubbles can easily cross the regular hexagonal patterns and converge into larger bubbles, increasing the risk of premature jumping.

[0097] In some implementations of this embodiment, the closed circle 301 is a circle.

[0098] In the above embodiment, the circular closed ring 301 better fits the air bubbles, effectively limiting their size compared to existing technologies, preventing them from forming an air film and reducing the risk of premature beats. Furthermore, by more effectively limiting the size of the air bubbles, the use of closed rings 301 of varying diameters can achieve even better noise reduction.

[0099] In the prior art, the engraved regular hexagonal patterns are of the same size, and there is no spacing between the regular hexagonal patterns. Therefore, bubbles can only be generated in the regular hexagonal patterns with a fixed size, which affects the noise reduction performance.

[0100] In some implementations of this embodiment, the distances between adjacent closed circles 301 are different.

[0101] In the above embodiment, the size of the gap differs from the size of the closed circle 301 forming the gap. However, bubbles can still be generated within this gap during water boiling. The size of the bubbles generated within this gap depends on the size of the inscribed circle that can be tangent to the closed circle 301. The diameter of this inscribed circle is affected by the diameter of the closed circle 301. Given the inherently varying diameters of the closed circle 301, the diameter of the inscribed circle often differs from that of the closed circle 301. This increases the discreteness of bubble sizes across the entire metal base plate 1, preventing bubbles from accumulating at similar sound wave frequencies. Different bubble bursting rhythms and eases prevent a large number of bubbles from bursting simultaneously, further encouraging other bubbles to escape from the surface of the metal base plate 1, improving noise performance.

[0102] The closed circles 301 with different spacing and / or different areas can be referred to as irregular closed circles 301 .

[0103] In some embodiments, Figure 7As shown, multiple groups of closed circles 301 with varying areas, spacing between them, varying areas and spacing between them, and rectangular regular circles 301 produce different noise levels when heating 1.5L of water at 1000W heating power with the lid closed. When the equivalent radius from the inner edge of the engraved area 3 to the center of the metal base plate 1 is no less than 0.55R, the water heating noise is lower. Given that further reduction of ambient noise is difficult, the differences introduced by the different types of closed circles 301 are relatively small, but still representative. The highest noise level was measured for the rectangular regular closed circle 301-1 (the first prototype), with a maximum noise level of 38.9dB. The lowest noise level was measured for the closed circles 301 with varying areas and spacing between them, with a maximum noise level of 37.5dB. Overall, the irregular closed circles 301 perform better than the rectangular regular closed circles 301. The rectangular regular closed circles 301 refer to closed circles 301 with the same area and abutting each other. The length and width of the rectangular regular closed circle 301 are both 2.5 mm.

[0104] In the prior art, uniform noise reduction intervals are applied across the entire inner bottom surface of the inner liner. It is believed that controlling the size of bubbles generated across the entire inner bottom surface is beneficial for both noise reduction and premature beat prevention. However, in actual use, it was discovered that leaving a non-engraved area 3 outside the outer diameter of the heating element 5 actually enhances the noise reduction effect.

[0105] In some implementations of this embodiment, the equivalent outer diameter of the engraving area 3 is larger than the equivalent outer diameter of the heating element 5 , and the equivalent outer diameter of the engraving area 3 is smaller than the equivalent outer diameter of the metal base plate 1 .

[0106] In the above embodiment, when the heating element 5 is heated, bubbles will be generated on the longitudinal projection surface and the edge of the projection surface of the heating element 5 on the metal base plate 1, and the bubbles will gather into large bubbles on the metal base plate 1. Since the temperature sensing element 4 is arranged on the inner side of the heating element 5, it is necessary to limit the inner diameter size of the engraving area 3. The convergence of bubbles outside the heating element 5 has little effect on the temperature sensing element 4. A non-engraving area can be set at the edge of the metal base plate 1, so that a small number of bubbles outside the engraving area 3 can be gathered, reducing the total number of small bubbles that burst, thereby further reducing the noise when boiling water. Since the non-engraving area is far away from the temperature sensing element 4, if small bubbles accidentally gather into an air film, the metal bottom from the heating element 5 to the temperature sensing element 4 can still transfer heat with the water, which has little effect on premature jumping.

[0107] Specifically, for an electric kettle with a heating power of 1000W and a capacity of 1.5L, the outer diameter of the heating tube can be 80mm, the equivalent diameter of the inner edge of the engraving area 3 can be 90mm, and the outer diameter of the metal base plate 1 can be 100mm.

[0108] In some implementations of this embodiment, the equivalent outer diameter of the metal hydrophobic film 2 is larger than the equivalent outer diameter of the engraving area 3 .

[0109] In the above embodiment, the metal hydrophobic film 2 can completely cover the metal bottom plate 1, further improving the anti-stick performance of the electric kettle.

[0110] The heating power of existing electric kettles is relatively high. To reduce the heat load of the heating element 5, it is necessary to increase the surface area of ​​the heating element 5. When the heating element 5 is a non-enclosed heating tube with openings, the distance between the openings is relatively short, and the connecting line between the openings may still generate an air film.

[0111] In some implementations of this embodiment, the heating element 5 is a non-enclosed heating tube with an opening, and the engraving area 3 covers a connecting line segment of the opening.

[0112] In the above embodiment, the engraved area 3 covers the connecting line segment, restricting the horizontal movement of bubbles in the connecting line segment and preventing the bubbles from converging into an air film there. The opening of the heating tube is often equipped with cables and terminals. If an air film forms at the opening connecting the segment, the temperature of the connecting line will be too high. Covering the engraved area 3 can prevent the cables and terminals from being damaged by long-term high temperatures.

[0113] In some implementations of this embodiment, the heating element 5 is a non-enclosed heating tube with an opening, and the temperature sensing area of ​​the temperature sensing element 4 is located on a side facing the opening.

[0114] In the above embodiment, the temperature at the opening of the heating tube is relatively lower than that of the heating tube body, resulting in fewer bubbles and a lower probability of bubbles converging into an air film at the opening. This is particularly true after the engraving area 3 covers the connecting line segment, making it even less likely for an air film to form at the opening. The temperature sensing area of ​​the temperature sensing element 4 is located on the side facing the opening, further enhancing the kettle's ability to prevent premature tripping.

[0115] In some embodiments, the heating element 5 may be two non-enclosed heating tubes with openings, and the heating tube with a larger equivalent diameter is arranged around the outside of the other heating tube, and the inner heating tube and the outer heating tube may be arranged concentrically.

[0116] The opening directions of the two heating tubes can be the same or different. When the opening directions of the two heating tubes are different, the temperature sensing area of ​​the temperature sensing element 4 can be set towards the opening direction of the inner heating tube to prevent bubbles from gathering into an air film near the temperature sensing element 4, further avoiding premature tripping.

[0117] In some implementations of this embodiment, the metal base plate 1 includes a transversely extending base plate, and the heating element 5 is arranged on the inner side of the outer edge of the base plate; or, the bottom of the metal base plate 1 includes an arc-shaped portion, and the heating element 5 is arranged on the outer wall of the arc-shaped portion.

[0118] In the above embodiment, when the heating element 5 is provided on the bottom plate, the contact surface between the laterally extending bottom plate and the heating element 5 is a plane, which facilitates the installation and positioning of the heating element 5 and the bottom plate.

[0119] When the heating element 5 is arranged on the arc portion, the contact surface between the heating element 5 and the arc portion is an arc surface, the contact area between the heating element 5 and the arc portion is larger, and the heat transfer efficiency between the heating element 5 and the arc portion is increased, thereby reducing the heat load of the heat transfer part of the arc portion, which is beneficial to reducing the total amount of bubbles generated.

[0120] In some implementations of this embodiment, the areas of adjacent closed circles 301 are different.

[0121] In the above embodiment, there is an area difference between adjacent closed circles 301, which causes the sizes of bubbles generated in the closed circle 301 to be different, and the periodic frequency of the bubbles generated and the frequency of the sound waves when they burst are also different, thereby reducing the probability of simultaneous bursting and resonance of the bubbles, and further improving the volume and timbre of the noise of the electric kettle.

[0122] There is an area difference between adjacent closed circles 301, and the rupture energy and rupture rhythm of adjacent closed circles 301 are different, which further avoids the common rupture when a large number of large bubbles rupture at the same time and reduces the noise when the electric kettle boils water.

[0123] In some implementations of this embodiment, there is an area difference between adjacent closed circles 301 of different areas, and the area difference is not less than the area of ​​the smallest closed circle 301 in the engraving area 3 .

[0124] In the above embodiment, the area difference between adjacent closed circles 301 is further limited, and there are large differences in the periodic frequency of adjacent bubble generation, the sound wave frequency of rupture, and the energy of rupture, which avoids the areas of adjacent closed circles 301 being too close and reduces interference and influence between bubbles.

[0125] The vibrations from the bubble bursting can be transmitted along the metal base plate 1 and can also be transmitted within the water. The larger the radius of the large bubble, the higher the height of the large bubble from the metal base plate 1. The vibrations from the bubble bursting are lost at the gas-liquid interface between the bubble and the water, resulting in the large bubble suppressing the vibrations of the other bubbles (especially the small bubbles). The greater the size difference between adjacent bubbles, the greater the height difference between the large and small bubbles, and the smaller the bubbles' vibrations tend to propagate through the water from a smaller angle. This limits the area difference between adjacent closed circles 301, which can enhance the suppressive effect of the large bubble on the small bubble.

[0126] Compared to the polygonal structures of the same area and shape in the prior art, the pattern in this embodiment comprises multiple groups of closed circles 301 with different areas, each with its own maximum bubble size. In actual use, it has been found that large bubbles can affect the cavitation effect of small bubbles, potentially suppressing or delaying their expansion, thereby reducing the noise of the kettle.

[0127] In some implementations of this embodiment, adjacent closed circles 301 are independent of each other, and the minimum distance between adjacent closed circles 301 is less than or equal to the equivalent diameter of the adjacent largest closed circle 301 .

[0128] In the above embodiment, the equivalent diameter of the closed circle 301 is smaller than the radial coverage width of the heating element 5, and bubbles can be generated between adjacent closed circles 301. The minimum spacing between adjacent closed circles 301 is not greater than the equivalent diameter of the adjacent largest closed circle 301, thereby preventing the bubbles outside the closed circle 301 from being too large, causing local dry burning of the metal base plate 1, and further avoiding dry burning of the electric kettle.

[0129] In some implementations of this embodiment, the average area of ​​the closed circle 301 covering the connecting line segment is larger than the average area of ​​the closed circle 301 covering the heating tube.

[0130] In the above embodiment, when the temperature of the connecting segment is high, it is still lower than the temperature of the metal base plate 1 corresponding to the heating tube. The number of bubbles at the connecting segment is small, and the closed circle 301 of the connecting segment can be larger than the closed circle 301 covering the heating tube, which can facilitate the bubbles in the connecting segment to gather into large bubbles, thereby further reducing noise.

[0131] In some implementations of this embodiment, the heating element 5 is a non-enclosed heating tube with an opening, the engraving area 3 covers the connecting segment of the opening, and the average area of ​​the closed circle 301 covering the connecting segment is larger than the average area of ​​the closed circle 301 covering the heating tube.

[0132] In the above embodiment, the engraved area 3 covers the connecting segment, restricting the horizontal movement of bubbles in the connecting segment and preventing them from converging into an air film. Cables and terminals are often located at the opening of the heating tube. If an air film forms at the open connecting segment, the temperature of the connecting segment will be too high. Covering the engraved area 3 can prevent the cables and terminals from being damaged by long-term high temperatures. Even when the temperature of the connecting segment is high, it is still lower than the temperature of the metal base plate 1 corresponding to the heating tube. The number of bubbles in the connecting segment is relatively small, and the closed ring 301 of the connecting segment can be larger than the closed ring 301 covering the heating tube. This allows bubbles in the connecting segment to converge into large bubbles, further reducing noise.

[0133] In some implementations of this embodiment, the average area of ​​the closed ring 301 located outside the equivalent outer diameter of the heating element 5 is greater than the average area of ​​the closed ring 301 located inside the equivalent inner diameter of the heating element 5 .

[0134] In the above embodiment, the area outside the equivalent outer diameter of the heating element 5 is farther away from the temperature sensing element 4, and the area inside the equivalent inner diameter of the heating element 5 is closer to the temperature sensing element 4. The average area of ​​the closed ring 301 outside the equivalent outer diameter of the heating element 5 is greater than the average area of ​​the closed ring 301 inside the equivalent inner diameter of the heating element 5, further preventing the bubbles inside the equivalent inner diameter of the heating element 5 from gathering into an air film, thereby further preventing the electric kettle from tripping prematurely.

[0135] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An electric kettle, characterized in that: The metal bottom plate comprises a heating element and a temperature sensing element arranged inside the heating element. The inner wall of the metal bottom plate is covered with a metal hydrophobic film in the corresponding area inside the outer end of the heating element. The metal hydrophobic film is engraved with lines to form an engraving area, the engraving area is formed by a plurality of closed circles, and the heating element is completely covered by the engraving area. The equivalent radius R from the inner edge of the heating element to the center of the metal base plate and the equivalent radius from the inner edge of the engraving area to the center of the metal base plate are not less than 0.55R.

2. The electric kettle according to claim 1, characterized in that: The equivalent radius from the inner edge of the engraving area to the center of the metal base plate is less than R.

3. The electric kettle according to claim 1, characterized in that: The equivalent diameter of the closed ring is smaller than half of the radial coverage width of the heating element.

4. The electric kettle according to claim 2, characterized in that: The engraving area is formed by arranging a plurality of closed circles with different equivalent diameters.

5. An electric kettle according to any one of claims 3 or 4, characterized in that: The closed circle is a circle.

6. The electric kettle according to claim 1, characterized in that: The equivalent outer diameter of the engraving area is larger than the equivalent outer diameter of the heating element, and the equivalent outer diameter of the engraving area is smaller than the equivalent outer diameter of the metal bottom plate.

7. The electric kettle according to claim 6, characterized in that: The equivalent outer diameter of the metal hydrophobic film is greater than the equivalent outer diameter of the engraving area.

8. The electric kettle according to claim 1, characterized in that: The heating element is a non-enclosed heating tube with an opening, and the engraving area covers a connecting line segment of the opening.

9. The electric kettle according to claim 1, characterized in that: The heating element is a non-enclosed heating tube with an opening, and the temperature sensing area of ​​the temperature sensing element is located on a side facing the opening.

10. The electric kettle according to claim 1, characterized in that: The metal bottom plate includes a transversely extending bottom plate, and the heating element is arranged on the inner side of the outer edge of the bottom plate; or the bottom of the metal bottom plate includes an arc-shaped portion, and the heating element is arranged on the outer wall of the arc-shaped portion.

Images