Electric kettle

Abstract

The invention provides an electric kettle, and relates to an electric kettle, the electric kettle comprises a metal bottom plate, the outer wall of the metal bottom plate is provided with a single-circle heating element in a surrounding manner, and a temperature sensing element is arranged on the inner side of the heating element; 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 present invention relates to the technical field of electric kettles, and in particular to an electric kettle. Background Art

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

[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 the heating element, and the heating element is controlled by temperature sensing elements such as temperature sensors. In addition to boiling water, the health kettle can also make scented tea, fruit tea and soup.

[0005] As people continue to pursue faster water boiling speed, the heating power of electric kettles continues to increase, which speeds up the water boiling process while also increasing the noise during boiling. Therefore, reducing the noise of water boiling without reducing the water boiling power has become the goal of everyone's research and development.

[0006] The early solution was to provide a shock absorber on the electric kettle to reduce the rupture of bubbles and thus drive the vibration of the electric kettle, thereby reducing the noise when boiling water. For example, patent CN201220529633.8 provides an electric kettle, which is provided with a sound-reducing ring on the heating plate, so that the bubbles emerging from the heating plate surface hit the sound-reducing ring to control the bubbles from rushing to the water surface to achieve noise reduction. However, it was found in use that if the sound-reducing ring is set in the heating liner, the sound-reducing ring will be repeatedly heated during multiple water boiling processes. During the repeated heating process, harmful substances in the sound-reducing ring may be continuously precipitated, affecting the health of use; at the same time, there is a gap between the sound-reducing ring and the inner wall of the heating liner, and foreign matter such as scale can enter between the sound-reducing ring and the inner wall of the heating liner, affecting the aesthetics of the heating liner and increasing the difficulty of cleaning the heating liner. The noise when boiling water mainly comes from the rupture of bubbles in the heating liner, especially the rupture of bubbles on the heating chassis. If the sound-reducing ring is set between the electric kettle body and the heating base, the mute effect is reduced.

[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 as 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 merging the small bubbles on the slope surface 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 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, in which 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 thermal convection of water vapor on the surface of the heat-collecting area, reduce the number of bubbles, and effectively reduce the generation of noise. The concave holes can also facilitate the aggregation of bubbles. A small number of small bubbles are more likely to gather on the surface of the concave holes, forming larger bubbles and drifting away from the bottom and then 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 that the effect of increasing the contact area between the surface of the heat-collecting area and the water is also limited, and 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 idea is to provide a hydrophobic coating on the heating bottom plate to promote the merging of bubbles into large bubbles. For example, an electric water heater provided by patent CN200720009531.2 includes an element plate, the element plate has an upper side and a lower side, the upper side is used to contact water, and the lower side has an electric heating element in thermal contact with it, the upper side has a noise reduction coating and / or treatment, and the container further includes a noise suppressor arranged above and near the element plate and extending substantially on the electric heating element, the suppressor includes a surface that converges or diverges in an upward direction. The patent promotes the small bubbles on the element plate to converge into large bubbles by providing a coating on the element plate. However, the patent mentioned in the specification that after 15 times of boiling water, the noise of the electric water heater increased, and the timbre of the noise was sharp, and it was necessary to additionally provide a suppressor on the element plate, which played a role in diversion and bubble convergence, reducing local boiling at the heater. Setting a suppressor in an electric kettle does not conform to the usage habits of consumers. At the same time, the suppressor needs to be manufactured separately, which affects the cost of the electric kettle.

[0011] At the same time, the prior art also mentions that a hydrophobic coating is provided on the heating base plate, so that small bubbles converge into large bubbles, especially bubbles are often generated in the projection area of ​​the heating element on the heating base plate, and the heat of the heating element corresponding to the heating base plate cannot be transferred to the temperature sensing element, which easily leads to premature tripping. In order to solve the premature tripping problem, the above patent CN200720009531.2 chooses to locally provide a coating in the area of ​​the heating base plate 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 sticking to the bottom of the kettle during cooking, electric kettles have to be completely equipped with a hydrophobic coating on the heating bottom plate. At this time, it is very important to solve the problem of hydrophobic coating, which is easy to cause premature tripping.

[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 be broken in time, and the heat can be transferred to the thermostat in time to prevent the occurrence of premature jump. In actual use, it was found that the polygonal structure described in the patent covers the entire surface of the bottom heating, 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] It is also found in actual use that water kettles often use hydrophobic coatings such as chemical coatings. Under high temperature and dry burning conditions, the chemical coatings are more likely to fall off, which not only affects their anti-stick effect, but also has a certain impact on human health.

[0015] Prior art CN202320452914.6, this patent proposes a non-stick pot, which uses a physical vapor deposition (PVD) process to form a metal protective film (equivalent to the metal hydrophobic film of the present application) on the pot. It uses a physical method (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 small molecular clusters of the 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; and 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, will not react after high temperature, and will not appear similar to the blueing phenomenon of 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] The 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 titanium, zinc metal, nickel metal, etc. Titanium also has high hardness, good friction resistance, and certain antibacterial properties, which is beneficial to improve the hygiene of the pot. Summary of the invention

[0019] The object of the present invention is to provide an electric kettle having a metal bottom plate 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 popping performance.

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

[0021] The embodiment of the present application provides an electric kettle, comprising a metal bottom plate, wherein the outer wall of the metal bottom plate is surrounded by a single-circle heating element and a temperature sensing element arranged 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 bottom plate and the equivalent radius from the inner edge of the engraving area to the center of the metal bottom 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 bottom 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 bottom plate comprises a laterally 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 comprises 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 is provided with an engraving area and an area not covered by the engraving area (hereinafter referred to as the non-engraving area). Because the engraving area completely covers the heating element, the non-engraving area is far away from the heating element, and the number of bubbles generated is small, so that the pattern is not engraved far away from the heating element, which prompts the small bubbles in the non-engraving area to move and gather, thereby further reducing the noise when boiling water; and because the number of bubbles generated in the non-engraving area is small, there is no need to worry about too many bubbles gathering into an air film. Compared with the existing technology, the noise reduction performance of the electric kettle is improved.

[0036] Because the temperature sensing element is arranged on the inner side of the heating element (the side of the geometric center of the heating element can be the inner side), in order to limit the bubbles inside the heating element from accidentally gathering into an air film, the inner edge of the engraving area can be wider than the inner edge of the heating element, thereby ensuring the anti-early tripping performance of the electric kettle. In addition, because the area of ​​the engraving area of ​​this embodiment is smaller than that of the prior art, the anti-sticking performance of the electric kettle is further ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the positional relationship of the metal bottom plate, the metal hydrophobic film, the sealing ring, the temperature sensing element and the heating element in the present invention;

[0038] Figure 2 It is a structural schematic diagram of the engraving area and the closed circle in the present invention;

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

[0040] Figure 4 A noise comparison table of the electric kettle with or without the metal hydrophobic film and with or without the engraving area of ​​the present invention;

[0041] Figure 5 A statistical table of the inner diameter of the engraving area, the area of ​​the engraving area, the residual amount and the noise of the engraving area of ​​the present invention;

[0042] Figure 6 A comparison diagram of the relationship between the engraving area and the noise in the present invention;

[0043] Figure 7 It is a comparison diagram of the closed loop type and noise in the present invention.

[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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0046] Embodiment 1

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

[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 bottom plate 1 and the equivalent radius from the inner edge of the engraving area 3 to the center of the metal bottom plate 1 are not less than 0.55R.

[0051] In this embodiment, the metal bottom plate 1 can be used to support the liquid and transfer heat to the liquid. The contact surface between the bottom plate and the liquid can be the inner wall of the metal bottom plate 1, and the part of the metal bottom plate 1 facing away from the inner wall can be the outer wall of the metal bottom plate 1. The bottom of the heating element 5 and the temperature sensing element 4 in contact with the metal bottom plate 1 is at least made of metal. Under the action of the plasma electric field, the evaporated substance or its reaction product of the target material (such as chromium, other metals and alloys, etc.) is deposited on the surface of the metal bottom plate 1, and the original uneven parts of the inner wall of the metal bottom plate 1 are repaired, and a smoother metal hydrophobic film 2 is formed on the inner wall of the metal bottom plate 1. Compared with the prior art, this embodiment does not use conventional chemical coatings, but a metal hydrophobic film 2 is set in the electric kettle, and the inner wall of the metal bottom plate 1 is smoother, which increases the flow rate of the surface water on the inner wall of the metal bottom plate 1 during the boiling process and reduces the retention of water on the surface of the inner wall of the metal bottom 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 treated by ionization impact is restored to 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 the long-term use of the electric kettle, scale will be deposited on the inner wall of the metal bottom plate 1, especially 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 inner wall of the heating element 5 on 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 inner wall of the heating element 5 on 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 the deposition of scale on the metal bottom plate 1.

[0054] When the existing heating element 5 is heating water, the heating power can often reach more than 800W, so that during the process of heating water (especially heating from 65 degrees to 95 degrees), the heating element 5 often generates a large number of small bubbles in the corresponding area of ​​the inner wall of the metal bottom plate 1, and some of the small bubbles burst on the inner wall of the metal bottom plate 1, generating a large noise. The inner wall of the metal bottom plate 1 is covered with a metal hydrophobic film 2 in the corresponding area inside the outer end of the heating element 5. Affected by the vibration of bubble bursting and the large surface flow velocity of the inner wall of the metal bottom plate 1, the small bubbles slide and merge on the inner wall of the metal bottom plate 1 to form large bubbles, reducing the number of bubble bursts and reducing the noise when boiling water.

[0055] like Figure 4 As described, 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 noise of the electric kettle with the metal hydrophobic film 2 and the engraving area 3 is the lowest, 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 gathering of small bubbles. As time goes by, large bubbles will gradually form a whole large air film. The formed air film isolates the water and the heating element 5 in the corresponding area of ​​the inner wall of the metal bottom 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, and the electric kettle is powered off, resulting in the water not being completely boiled (hereinafter referred to as premature jump).

[0057] In the prior art, a suppressor needs to be installed in the inner pot to guide the bubbles to flow to the upper side of the inner pot and prevent the bubbles from gathering at the bottom of the inner pot, so as to reduce the premature tripping of the electric kettle. However, installing a suppressor in the inner pot does not conform to the user's usage habits, and the suppressor hinders the user from cooking food with the electric kettle, affecting normal use.

[0058] In this embodiment, the metal hydrophobic film 2 is engraved with patterns 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, change the microstructure of the metal hydrophobic film 2, and 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, preventing the sliding distance of the bubbles from being too long and controlling the speed at which small bubbles converge into large bubbles. At the same time, in the process of small bubbles converging, the contact edge of the large bubble with the metal hydrophobic film 2 gradually expands, and 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. In the present embodiment, during the process of boiling water, small bubbles are prevented from moving quickly and gathering into large bubbles, and the size of large bubbles is also prevented from continuously expanding into air films; 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 jump prematurely without affecting the use of the user.

[0060] Some prior art solves the problem of premature tripping of electric kettles covered with hydrophobic membranes by evenly arranging polygonal structures on the bottom of the inner pot, especially the polygonal structures need to cover the area where the temperature sensing element 4 is located. However, the prior art requires laser cutting of the entire bottom of the inner pot, which affects the anti-sticking performance of the electric kettle.

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

[0062] This embodiment adopts a technical idea that is completely different from the prior art. 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 getting stuck 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 heat transfer along the thickness of the metal base plate 1 and heat 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 with the prior art, the present embodiment is provided with an engraving area 3 and an area not covered by the engraving area 3 (hereinafter referred to as a non-engraving area). Because the engraving area 3 completely covers the heating element 5, the non-engraving area is far away from the heating element 5, and the number of bubbles generated is small, so that the pattern is not engraved far away from the heating element 5, which prompts the small bubbles in the non-engraving area to move and gather, thereby further reducing the noise when boiling water; and because the number of bubbles generated in the non-engraving area is small, there is no need to worry about too many bubbles gathering into an air film. Compared with the prior art, the noise reduction performance of the electric kettle is improved.

[0065] Because the temperature sensing element 4 is arranged inside the heating element 5 (the side of the geometric center of the heating element 5 can be the inside), in order to limit the bubbles inside the heating element 5 from accidentally gathering into an air film, the inner edge of the engraving area 3 can be wider than the inner edge of the heating element 5, thereby ensuring the anti-early tripping performance of the electric kettle. In addition, because the area of ​​the engraving area 3 in this embodiment is smaller than that of the prior art, the anti-sticking performance of the electric kettle 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 modes; when the metal hydrophobic film 2 is not engraved with patterns, 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 at 1184 mm. 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 bottom plate 1 in this embodiment is not less than 0.55R.

[0069] In some implementations, 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 the electric kettle from being damaged.

[0071] In some embodiments, a glass side wall may be provided on the outer peripheral side of the metal bottom plate 1 .

[0072] In some embodiments, the single-circle heating element 5 may be a C-shaped heating tube or a single-circle annular heating tube. When the heating element 5 is a circular 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 ellipse or other ring-shaped shape, or other shapes that are not circular, the equivalent diameter can be calculated.

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

[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 of the C-type heating tube during 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-turn heating element 5, thereby increasing the contact area between the heating element 5 and the metal bottom plate 1. When the heating power of the heating element 5 is the same, the heat load per unit area of ​​the metal bottom plate 1 is reduced, and the noise of boiling water in the electric kettle can be further reduced. When the heating element 5 is a multi-turn heating element 5, the overall width of the heating element 5 may increase, which may cause the edge of the heating element 5 to be closer to the temperature sensing element 4. At this time, in order to prevent bubbles from gathering into an air film near the temperature sensing element 4, the extension range of the engraving area 3 to 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 is 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, and the heating power is often 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 the like, 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, and the bubbles on the inner edge of the heating element 5 are too large, the electric kettle may still 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 inwardly 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 circle 301 can be carved with annular patterns. When boiling water, bubbles can be generated in the closed circle 301. Since the patterns of the closed circle 301 restrict the movement of bubbles, the size of the bubbles in the closed circle 301 depends on the size of the closed circle 301.

[0085] In order to prevent the bubbles from being too large and causing local dry-burning and premature tripping, the equivalent diameter of the closed circle 301 is limited to be smaller than the width of the heating element 5 in this embodiment. Preferably, the equivalent diameter of the closed circle 301 is smaller than half of the width of the heating element 5, that is, the projection of multiple closed circles 301 and the heating element 5 on the metal bottom plate 1 overlap, and the size of the closed circle 301 is relatively small. The process of the bubbles gradually growing larger and eventually breaking or detaching is relatively short. When the heating element 5 is provided with multiple smaller closed circles 301, the bubbles in some closed circles 301 are in the process of growing larger, breaking and detaching, and the remaining closed circles 301 can still contact with water for heat transfer, reducing the probability of the electric kettle being dry-burned and prematurely tripping.

[0086] The engraving area 3 may adopt a closed circle 301 in a circular, rectangular, or triangular shape, or 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), wherein A represents the area enclosed by the edge, and π represents the pi.

[0088] Among them, adjacent closed circles 301 in the engraving area 3 can be arranged in a colinear 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 distance and vertical distance.

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

[0091] In the above embodiment, due to process limitations, the average thickness of the hydrophobic film is 0.5-1.5 μm, and the depth h is not too deep. If the depth h is too deep, the metal hydrophobic film 2 is easily damaged, affecting the non-stickiness of the electric kettle. If the metal bottom plate 1 is a hydrophilic material, the depth h is too deep, and water can directly contact the hydrophilic metal bottom plate 1, affecting the limiting effect of the closed ring 301 on the size of the bubbles, thereby affecting the effect of preventing premature jump and reducing noise of the electric kettle.

[0092] In the above embodiment, the width w should not be too large or too small. The bubbles inside and outside the closed circle 301 should originally contact the texture to limit the size of the bubbles. When the width w is too large, bubbles may be generated inside the texture. The surface friction between the bubbles and the texture is small, and the bubbles are easy to gather and escape with the bubbles and the texture, making it difficult for the closed circle 301 to limit the size of the bubbles, affecting the effect of preventing premature jump and reducing noise of the electric kettle.

[0093] When the width w is too small, the process will be difficult to implement and the production cost will increase significantly. Of course, it is not ruled out that with the development of process technology in the future, a smaller width w can be obtained at a lower cost.

[0094] In some implementations of this embodiment, the engraving area 3 is formed by arranging a plurality of closed circles 301 with different equivalent diameters.

[0095] In the prior art, in order to limit the maximum size of bubbles generated, closed lines of the same size and shape are often engraved. However, it is found during use that because the engraving size and shape are the same (especially the same size), the maximum size of the generated bubbles will be consistent. Since the maximum size of the bubbles is consistent, the time from bubble growth to falling off or bursting is relatively consistent, which makes it easy for a large number of bubbles to burst at a similar rhythm, thereby increasing the noise. Although the time from bubble growth to falling off or bursting is short, the number of bubbles generated when boiling water is large, and the noise generated by the bursting of similar bubbles is at a similar sound wave frequency, which may make it easier for users to perceive the noise.

[0096] In some embodiments, the sizes of the closed circle 301 are different, and the maximum sizes of the bubbles generated in the closed circle 301 are different. Small bubbles converge into bubbles of different sizes, which still reduces the total amount of bubble rupture. By interfering with the maximum size of the bubbles, the time from bubble growth to falling off or rupture is affected, and a large number of bubbles are prevented from rupturing at a similar rhythm, and a large number of bubbles are prevented from rupturing at the same time, reducing possible resonance and improving the noise performance of the electric kettle. At the same time, by interfering with the maximum size of the bubbles, the sound wave frequency when the bubbles rupture is changed, and a large number of bubbles are prevented from emitting the same or similar sound wave frequency, further improving the user's hearing.

[0097] Compared with the polygonal structure with the same area and shape in the prior art, in this embodiment, the pattern includes multiple groups of closed circles 301 with different areas, and the maximum size of bubbles in the closed circles 301 with different areas is different. In actual use, it is found that large bubbles will affect the cavitation effect of small bubbles, and large bubbles may cause the vibration of small bubbles to be suppressed or delayed expansion, thereby reducing the noise of the kettle.

[0098] The area and shape of the polygonal structure in the prior art are the same, so that the bubbles generated by the prior art are mostly large bubbles, and the larger the bubble, the higher the energy of bursting. When a large number of large bubbles burst at a similar frequency, the higher energy makes it easy for other bubbles to burst together. In this embodiment, the pattern includes multiple groups of closed circles 301 with different areas, and bubbles of different sizes and energies are difficult to burst in large numbers at the same time, reducing the situation of common bursting. At the same time, in this embodiment, the energy of small bubbles after bursting is small, and the vibration generated is difficult to burst other bubbles. On the contrary, its vibration will prompt other bubbles to leave the surface of the metal bottom plate 1, thereby further reducing noise.

[0099] In the prior art, people 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 in restricting the bubbles. Bubbles can easily cross the regular hexagonal patterns and converge into larger bubbles, increasing the risk of premature jumping.

[0100] In some implementations of this embodiment, the closed circle 301 is a circle.

[0101] In the above embodiment, the closed circle 301 of the circle fits better with the air bubble, and can more effectively limit the size of the air bubble than the prior art, prevent the air bubble from gathering into an air film, and reduce the risk of premature jump. At the same time, the size of the air bubble can be more effectively limited, and the closed circle 301 with different diameters can be used to achieve a better noise reduction effect.

[0102] In the prior art, the engraved regular hexagonal patterns have the same size, and there is no spacing between the regular hexagonal patterns. Bubbles can only be generated in the regular hexagonal patterns with a fixed size, which affects the noise reduction performance.

[0103] In some implementations of this embodiment, the intervals between adjacent closed circles 301 are different.

[0104] In the above embodiment, the size of the spacing is different from the size of the closed circle 301 forming the gap. When boiling water, the above spacing can still generate bubbles. The size of the bubbles generated in the spacing depends on the inscribed circle that can be tangent to the closed circle 301. The diameter of the inscribed circle is affected by the diameter of the closed circle 301. In the case where the diameter of the closed circle 301 is different, the diameter of the inscribed circle is often different from the diameter of the closed circle 301, thereby increasing the discreteness of the size of the bubbles generated by the entire metal bottom plate 1, thereby avoiding bubbles at similar sound wave frequencies; different bubble bursting rhythms and difficulty levels make it difficult for a large number of bubbles to burst at the same time, and further promote other bubbles to leave the surface of the metal bottom plate 1, thereby improving noise performance.

[0105] The closed circles 301 with different spacings and / or different areas can be referred to as irregular closed circles 301 .

[0106] In some embodiments, Figure 7 As shown, multiple groups of closed circles 301 with different areas, closed circles 301 with spacing, closed circles 301 with different areas and spacing, and rectangular regular closed circles 301, at a heating power of 1000W, heating 1.5L of water, and closing the lid to boil water have different noises. When the equivalent radius from the inner edge of the engraving area 3 to the center of the metal bottom plate 1 is not less than 0.55R, the water boiling noise is low. When the environmental noise is difficult to further reduce, the difference brought by different types of closed circles 301 is small, but still representative. Among them, the maximum noise measured is the rectangular regular closed circle 301-1 (the first prototype), with a maximum noise of 38.9dB; among them, the minimum noise measured is the closed circle 301 with different areas and spacing, with a maximum noise of 37.5dB. Overall, the noise performance of the irregular closed circle 301 is better than that of the rectangular regular closed circle 301. Among them, the rectangular regular closed circle 301 refers to the closed circle 301 in which each closed circle 301 has the same area and is close to each other. The length and width of the rectangular regular closed circle 301 are both 2.5 mm.

[0107] In the prior art, the same noise reduction interval covers the entire inner bottom surface of the inner tank. The prior art believes that the size of the bubbles generated needs to be controlled on the entire inner bottom surface of the inner tank, which is conducive to solving the problems of noise reduction and preventing premature jumps. However, in actual use, it is found that leaving a non-engraving area 3 outside the outer diameter of the heating element 5 will improve the noise reduction effect.

[0108] In some implementations of this embodiment, the equivalent outer diameter of the engraving area 3 is greater 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 bottom plate 1 .

[0109] 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 metal bottom plate 1 of the heating element 5, and the bubbles will gather into large bubbles on the metal bottom 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 bottom plate 1, so that a small number of bubbles outside the engraving area 3 can be gathered, reducing the total number of small bubble ruptures, 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.

[0110] 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.

[0111] In some implementations of this embodiment, the equivalent outer diameter of the metal hydrophobic film 2 is greater than the equivalent outer diameter of the engraving area 3 .

[0112] 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.

[0113] The heating power of the existing electric kettle is relatively large, and in order 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 segment between the openings may still generate an air film.

[0114] 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.

[0115] In the above embodiment, the engraving area 3 covers the connecting line segment, and the engraving area 3 limits the horizontal movement of the bubbles in the connecting line segment to prevent the bubbles from gathering into an air film in the connecting line segment. The opening of the heating tube is often provided with cables and terminals. If an air film is generated at the opening connecting line segment, the temperature of the connecting line segment is too high. Covering with the engraving area 3 can prevent the cables and terminals from being damaged under long-term high temperature.

[0116] 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.

[0117] In the above embodiment, the temperature at the opening of the heating tube is relatively lower than the temperature of the heating tube body, the number of bubbles generated is small, and the probability of bubbles gathering into an air film at the opening is small, especially after the engraving area 3 covers the connecting line segment, it is more difficult to generate an air film at the opening. The temperature sensing area of ​​the temperature sensing element 4 is located on the side facing the above opening direction, which further improves the effect of preventing the electric kettle from tripping prematurely.

[0118] 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.

[0119] 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 toward 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.

[0120] In some implementations of this embodiment, the metal bottom plate 1 includes a laterally extending bottom plate, and the heating element 5 is arranged on the inner side of the outer edge of the bottom plate; or, the bottom of the metal bottom plate 1 includes an arc-shaped portion, and the heating element 5 is arranged on the outer wall of the arc-shaped portion.

[0121] In the above embodiment, when the heating element 5 is disposed 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.

[0122] When the heating element 5 is arranged on the arc-shaped portion, the contact surface between the heating element 5 and the arc-shaped portion is an arc surface, the contact area between the heating element 5 and the arc-shaped portion is larger, and the heat transfer efficiency between the heating element 5 and the arc-shaped portion is increased, thereby reducing the heat load of the heat transfer part of the arc-shaped portion, which is beneficial to reducing the total amount of bubble generation.

[0123] In some implementations of this embodiment, the areas of adjacent closed circles 301 are different.

[0124] In the above embodiment, there is an area difference between adjacent closed circles 301, which causes the bubble sizes generated in the closed circle 301 to be different, and the periodic frequency of each bubble generation and the sound wave frequency of the rupture are also different, thereby reducing the probability of simultaneous rupture and resonance of the bubbles, and further improving the volume and timbre of the electric kettle noise.

[0125] There is an area difference between adjacent closed circles 301, and the rupture energies and rupture rhythms 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.

[0126] 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 .

[0127] 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, thereby avoiding the areas of adjacent closed circles 301 being too close and reducing interference and influence between bubbles.

[0128] The vibration when the bubble bursts can be transmitted along the metal bottom plate 1, and the vibration when the bubble bursts can also be transmitted in the water. The radius of the large bubble is large, so that the large bubble is at a higher height of the metal bottom plate 1. The vibration of the bubble bursting is lost at the gas-liquid contact surface between the bubble and the water, so the large bubble has a vibration suppression effect on the bubbles (especially the small bubbles); when the size difference between adjacent bubbles is larger, the height difference between the large bubble and the small bubble is larger, and the vibration of the small bubble tends to propagate in the water from a smaller angle, which limits the area difference between adjacent closed circles 301 to be larger, which can increase the vibration suppression effect of the large bubble on the small bubble.

[0129] Compared with the polygonal structure with the same area and shape in the prior art, in this embodiment, the pattern includes multiple groups of closed circles 301 with different areas, and the maximum size of bubbles in the closed circles 301 with different areas is different. In actual use, it is found that large bubbles will affect the cavitation effect of small bubbles, and large bubbles may cause small bubbles to be suppressed or delayed in expansion, thereby reducing the noise of the kettle.

[0130] In some implementations of this embodiment, adjacent closed circles 301 are independent of each other, and the minimum spacing between adjacent closed circles 301 is less than or equal to the equivalent diameter of the adjacent largest closed circle 301 .

[0131] In the above embodiment, the equivalent diameter of the closed circle 301 is smaller than the radial coverage width of the heating element 5, bubbles can be generated between adjacent closed circles 301, and 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.

[0132] 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.

[0133] In the above embodiment, when the temperature of the connecting segment is high, it is still lower than the temperature of the metal bottom 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.

[0134] 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 line segment of the opening, and 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.

[0135] In the above embodiment, the engraving area 3 covers the connecting line segment, and the engraving area 3 limits the horizontal movement of the bubbles in the connecting line segment to prevent the bubbles from gathering into an air film in the connecting line segment. The opening of the heating tube is often provided with cables and terminals. If an air film is generated at the opening connecting line segment, the temperature of the connecting line segment is too high. The engraving area 3 covers to prevent the cables and terminals from being damaged under long-term high temperature. When the temperature of the connecting line segment is high, it is still lower than the temperature of the corresponding metal bottom plate 1 of the heating tube. The number of bubbles at the connecting line segment is small, and the closed circle 301 of the connecting line segment can be larger than the closed circle 301 covering the heating tube, which can facilitate the bubbles in the connecting line segment to gather into large bubbles, thereby further reducing noise.

[0136] In some implementations of this embodiment, the average area of ​​the closed circle 301 located outside the equivalent outer diameter of the heating element 5 is greater than the average area of ​​the closed circle 301 located inside the equivalent inner diameter of the heating element 5 .

[0137] 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 inside of the equivalent inner diameter of the heating element 5 is closer to the temperature sensing element 4. The average area of ​​the closed circle 301 outside the equivalent outer diameter of the heating element 5 is larger than the average area of ​​the closed circle 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.

[0138] In some implementations of this embodiment, the average area of ​​the closed circle 301 covering the outside of the heating element 5 is greater than the average area of ​​the closed circle 301 covering the heating tube.

[0139] In the above embodiment, the temperature of the closed circle 301 outside the heating element 5 is still lower than the temperature of the metal bottom plate 1 corresponding to the heating tube, the number of bubbles at the corresponding metal bottom plate 1 outside the heating tube is small, and the average area of ​​the closed circle 301 covering the outside of the heating element 5 is larger than the average area of ​​the closed circle 301 covering the heating tube, which can facilitate the bubbles at the corresponding metal bottom plate 1 outside the heating tube to gather into large bubbles, thereby further reducing noise.

[0140] In some implementations of this embodiment, the distance between adjacent closed circles 301 is smaller than the equivalent diameter of the smallest adjacent closed circle 301 .

[0141] In the above embodiment, the spacing between the closed circles 301 is further limited so that the bubbles generated between the closed circles 301 are smaller than the size of the bubbles inside the closed circles 301. When the spacing between the closed circles 301 is too large, the limiting effect of the closed circles 301 on the bubbles outside the closed circles 301 is reduced, and the bubbles are easy to escape from between the closed circles 301, thereby preventing the bubbles from accidentally gathering into an air film between the closed circles 301.

[0142] In some implementations of this embodiment, the equivalent outer diameter of the above-mentioned engraving area 3 is larger than the equivalent outer diameter of the heating element 5, the equivalent outer diameter of the above-mentioned engraving area 3 is smaller than the equivalent outer diameter of the metal base plate 1, and the average spacing of the above-mentioned closed circle 301 covering the outside of the equivalent outer diameter of the heating element 5 is greater than the average spacing of the above-mentioned closed circle 301 covering the heating element 5.

[0143] In the above embodiment, the temperature of the closed circle 301 outside the heating element 5 is still lower than the temperature of the metal bottom plate 1 corresponding to the heating tube, the number of bubbles at the corresponding metal bottom plate 1 outside the heating tube is small, and the average spacing of the closed circle 301 covering the outside of the heating element 5 is larger than the average spacing of the closed circle 301 covering the heating tube, which can facilitate the bubbles at the corresponding metal bottom plate 1 outside the heating tube to gather into large bubbles, thereby further reducing noise.

[0144] In some implementations of this embodiment, the average spacing of the closed circles 301 covering the heating element 5 gradually decreases toward the direction approaching the temperature sensing element 4 .

[0145] In the above embodiment, between the closed circles 301 covering the heating element 5, the larger the average spacing of the closed circles 301, the easier it is for the bubbles outside the closed circles 301 to converge into an air film, and the bubbles outside the closed circles 301 tend to converge to the place with a larger spacing. In this embodiment, the average spacing of the closed circles 301 gradually decreases toward the direction close to the temperature sensing element 4, preventing the bubbles from converging toward the temperature sensing element 4, preventing the metal bottom plate 1 near the temperature sensing element 4 from dry burning, and avoiding the probability of premature tripping of the electric kettle.

[0146] In some implementations of this embodiment, the equivalent outer diameter of the above-mentioned engraving area 3 is larger than the equivalent outer diameter of the heating element 5, the equivalent outer diameter of the above-mentioned engraving area 3 is smaller than the equivalent outer diameter of the metal base plate 1, and the average area of ​​the above-mentioned closed circle 301 covering the outside of the equivalent outer diameter of the heating element 5 is larger than the average area of ​​the above-mentioned closed circle 301 covering the inside of the equivalent inner diameter of the heating element 5.

[0147] 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 metal bottom plate 1 of the heating element 5, and the bubbles will gather into large bubbles on the metal bottom 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 bottom plate 1, so that a small number of bubbles outside the engraving area 3 can be gathered, reducing the total number of small bubble ruptures, 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.

[0148] The area outside the equivalent outer diameter of the heating element 5 is far away from the temperature sensing element 4, and the inner side of the equivalent inner diameter of the heating element 5 is closer to the temperature sensing element 4. The average area of ​​the above-mentioned closed circle 301 covering the outer side of the equivalent outer diameter of the heating element 5 is larger than the average area of ​​the above-mentioned closed circle 301 covering the inner side of 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.

[0149] 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 line segment of the opening, and the average spacing of the closed circles 301 located in the connecting line segment is greater than the average spacing of the closed circles 301 located in the heating tube.

[0150] In the above embodiment, the engraving area 3 covers the connecting line segment, and the engraving area 3 limits the horizontal movement of the bubbles in the connecting line segment to prevent the bubbles from gathering into an air film in the connecting line segment. The opening of the heating tube is often provided with cables and terminals. If an air film is generated at the opening connecting line segment, the temperature of the connecting line segment is too high. The engraving area 3 covers to prevent the cables and terminals from being damaged under long-term high temperature. When the temperature of the connecting line segment is high, it is still lower than the temperature of the corresponding metal bottom plate 1 of the heating tube. The number of bubbles at the connecting line segment is small, and the average spacing of the above-mentioned closed circle 301 at the connecting line segment is larger than the average spacing of the above-mentioned closed circle 301 at the heating tube, which can facilitate the bubbles in the connecting line segment to gather into large bubbles, thereby further reducing noise.

[0151] In the prior art, in order to limit the maximum size of bubbles generated, closed lines are often arranged close to each other, and bubbles cannot form between the closed lines. At the same time, the size and shape of the closed lines in the prior art are the same, resulting in the same maximum size of bubbles in the closed lines. This makes the maximum size of bubbles in the prior art consistent, and the time it takes for bubbles to grow, fall off or burst is relatively consistent, which makes it easy for a large number of bubbles to burst at a similar rhythm, thereby increasing the 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 bursting of bubbles of similar sizes produces similar pulses, so the bursting noise is at a similar sound wave frequency, which may make it easier for users to perceive the noise.

[0152] In this embodiment, the spacing between adjacent closed circles 301 is smaller than the equivalent diameter of the adjacent closed circles 301, so that the size of the bubbles generated between the closed circles 301 is smaller than the size of the bubbles in the closed circles 301. Even if the bubbles in the closed circles 301 are the same size, at least two bubbles with different maximum sizes can be generated in the engraving area 3. By interfering with the maximum size of the bubbles, the time from the growth to the shedding or rupture of the bubbles is affected, and a large number of bubbles are prevented from rupturing at a similar rhythm, and a large number of bubbles are prevented from rupturing at the same time, reducing possible resonance and improving the noise performance of the electric kettle. At the same time, by interfering with the maximum size of the bubbles, the sound wave frequency when the bubbles rupture is changed, and a large number of bubbles are prevented from emitting the same or similar sound wave frequencies, further improving the user's hearing.

[0153] In this embodiment, the equivalent diameter of the closed ring 301 is smaller than the radial coverage width of the heating element 5, and the closed ring 301 covers the heating element 5. In this embodiment, the equivalent diameter of the closed ring 301 is limited to be smaller than the radial coverage width of the heating element 5, that is, there is overlap between the projection of the multiple closed rings 301 and the heating element 5 on the metal bottom plate 1, and the size of the closed ring 301 is relatively small. The process of the bubbles gradually growing larger and eventually rupturing or detaching is relatively short. When the heating element 5 is provided with multiple smaller closed rings 301, the bubbles of some closed rings 301 are in the process of growing larger, rupturing and detaching, and the remaining closed rings 301 can still contact with water for heat transfer, reducing the probability of the electric kettle tripping due to dry boiling.

[0154] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electric kettle, characterized in that: It comprises a metal bottom plate, the outer wall of which is surrounded by a single-circle 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 engraved lines on the metal hydrophobic film form an engraved area, the heating element is completely covered by the engraved 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 engraved area to the center of the metal base plate is not less than 0.55R.

2. An 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 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.

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. An 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 comprises a bottom plate extending transversely, 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 comprises an arc-shaped portion, and the heating element is arranged on the outer wall of the arc-shaped portion.

Images