Liquid heater

Abstract

The utility model discloses a liquid heater, which belongs to the field of life electric appliances, solves the problem of larger heat energy loss of a heating tube, and adopts the technical scheme that the heating tube comprises a tube body, a heat conduction material and a heating wire, and the outer surface of the tube body comprises a second arc-shaped surface, an outer side surface, an outer bottom surface and an arc-shaped transition surface, intersecting lines of the second arc-shaped surface, the outer side surface, the outer bottom surface and the arc-shaped transition surface with the longitudinal section of the heating tube are a first arc line, a first curve, a second curve and a second arc line respectively, the first arc line is located between the first curve and the second curve, and the second arc line is located between the first curve and the second curve; the length of the first arc line is larger than the length of the first curve, the length of the second curve and the length of the second arc line, the distance between the heating wire and the second arc-shaped face is S1, the distance between the heating wire and the vertex of the arc-shaped transition face is S2, and S1 is smaller than half of S2. The heating tube is mainly used for improving the heat efficiency of the heating tube.

Description

Technical Field

[0001] The utility model relates to a household electrical appliance, in particular to a liquid heater. Background Art

[0002] In the liquid heaters in the prior art, the heating plate generally adopts a flat bottom structure, and the heating tube is also provided with a plane structure correspondingly to the heat conducting plate of the heating plate to ensure a certain heat conduction efficiency. For example, the utility model patent with the authorization announcement number CN211270048U discloses a noise-reducing electric kettle, comprising a kettle lid, a kettle body, a heating plate assembly, a thermostat and a bottom cover, wherein the heating plate assembly is sealed and fixedly connected to the kettle body, and the heating plate assembly comprises a chassis, a heating tube and a heat-conducting aluminum plate, wherein the chassis is a composite plate, and the composite plate comprises a stainless steel layer and an aluminum layer, and the chassis is provided with a first convex rib and a first concave cavity formed by stamping the aluminum layer upward toward the stainless steel layer, and the aluminum layer is provided with a heat collecting area and a heat conducting area, and the heat collecting area corresponds to the shape of the heating tube. In conjunction with the accompanying drawings, it can be seen that the heat-conducting aluminum plate is basically a flat plate structure, and the cross-section of the heating tube is a trapezoidal structure, and the wider upper bottom surface of the heating tube is in contact with the heat-conducting aluminum plate. However, only one surface of the heating tube is in contact with the heat-conducting plate, which accounts for less than 30% of the outer surface of the heating tube. The heat generated by the heating tube will radiate outward through other surfaces, resulting in a large loss of heat energy. In addition to the trapezoidal structure of the heating tube, there is also a prior art that processes the cross-section of the heating tube into a triangle. For example, the utility model patent with the authorization announcement number CN201848492U discloses a heating tube with an equilateral triangle cross-section. However, the contact area of the heating tube with this structure and the heat-conducting aluminum plate still only accounts for about 30% of the outer surface of the heating tube. After the heating tube is working, a large amount of heat energy will still be lost due to radiation.

[0003] In addition to heating plates with flat bottom structures, the prior art also discloses heating plates with curved bottom structures. For example, the invention patent application with publication number CN117958595A discloses an electric kettle, which discloses an inner pot including a pot body and a bottom wall, the bottom wall being connected to the bottom end of the pot body, a heat conducting plate being fixed to the outer surface of the bottom wall, a heating element being fixed to the outer surface of the heat conducting plate, a thermostat being arranged on the outer surface of the heat conducting plate and electrically connected to the heating element, and the inner surface of the bottom wall including a curved surface extending outward and upward from the center, wherein the heating element also uses a heating tube with a trapezoidal cross-section. For another example, the utility model patent with authorization publication number CN221511585U also discloses an inner pot bottom having a curved surface structure, wherein the cross-section of the heating element is an irregular polygonal structure. In this case, the contact area between the heating tube and the curved surface is relatively low as a proportion of the outer surface of the heating tube, and a large amount of heat energy is still lost due to radiation after the heating tube is in operation.

[0004] In addition, the heating tube generally includes a tube body, a heat-conducting material and a heating wire. The tube body is sleeved on the outside of the heating wire, and the heat-conducting material is filled between the heating wire and the tube body. For example, in the above-mentioned CN201848492U utility model patent, the heating wire (resistance wire 23) is relatively centered relative to the tube body (outer tube 21). The heat generated by the heating wire after being energized will be transferred more evenly to the periphery of the tube body, and the heating uniformity is better. However, this also causes the heat energy of the heating wire to be radiated to the surface of the tube body that is not in contact with the heating plate, resulting in a large heat energy loss. Utility Model Content

[0005] The purpose of the present invention is to provide a liquid heater to solve the problem of large heat energy loss in the heating tube, increase the ratio of the contact area of heat conduction between the heating tube and the inner tank to the surface area of the heating tube, and at the same time make the heating wire of the heating tube closer to the inner tank, thereby reducing heat energy loss and improving the thermal efficiency of the heating tube.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solution: a liquid heater, comprising an inner tank and a heating tube, the outer bottom surface of the inner tank having a first curved surface convex outwardly, the heating tube being fixed to the first curved surface, the heating tube comprising a tube body, a heat-conducting material and a heating wire, the tube body being sleeved on the outer side of the heating wire, the heat-conducting material being filled between the heating wire and the tube body, the outer surface of the tube body comprising a second curved surface, an outer side surface, an outer bottom surface and a curved transition surface, the second curved surface being concave in the tube body and fitting into the first curved surface, the curved transition surface being convex outwardly and relative to the second curved surface The curved surface is away from the first curved surface, and the intersection lines of the second curved surface, the outer side surface, the outer bottom surface and the curved transition surface with the longitudinal section of the heating tube are the first arc line, the first curve, the second curve and the second arc line respectively. The first arc line is located between the first curve and the second curve, and the second arc line is located between the first curve and the second curve. The length of the first arc line is greater than the length of the first curve, the second curve and the second arc line. The distance from the heating wire to the second curved surface is S1, and the distance from the heating wire to the vertex of the curved transition surface is S2, and S1 is less than half of S2.

[0007] After adopting the above technical solution, the utility model has the following advantages: the longitudinal cross-section of the tube body of the heating tube adopts a structure close to a triangle, wherein the length of the first arc is greater than the lengths of the first curve, the second curve, and the second arc, which is equivalent to using the longest side of the triangle to contact and fit the first arc surface, so that the proportion of the contact area between the heating tube and the inner pot to the outer surface area of the heating tube can be increased to more than 35%, which not only increases the proportion of heat energy generated by the heating tube during operation that is conducted to the inner pot, but also reduces the radiation loss of heat energy generated by the heating tube during operation. At the same time, S1 is controlled to be less than half of S2, that is, the heating wire is closer to the inner pot, and the heat energy generated by the heating tube during operation can be conducted to the inner pot faster and more effectively, thereby improving the thermal efficiency of the heating tube.

[0008] Furthermore, the first curve includes a first line segment, and the first line segment is inclined outward from bottom to top relative to the outer bottom surface.

[0009] Using the aforementioned technical solution, the outer surface of the tube body is designed into the aforementioned shape. During the press-forming process, the force exerted by the mold on the tube body can be transferred to the internal heating wire. This not only allows the heating wire to approach the second curved surface, ensuring that the design requirement of S1 being less than half of S2 is met, but also allows the shape of the heating wire projected on the longitudinal cross-section to be deformed to a shape close to the longitudinal cross-section of the tube body, thereby increasing the length of heat transfer from the heating wire to the second curved surface, which is beneficial for improving heating efficiency. In addition, the outward inclination of the first line segment from bottom to top relative to the outer bottom surface also facilitates demolding after press-forming.

[0010] Furthermore, the second curve includes a second line segment, and the angle C between the second line segment and the first line segment is ≥92°; and / or the second curve includes a second line segment, and the length of the second line segment is greater than or equal to the length of the first line segment.

[0011] By adopting the above-mentioned technical solution, the second curve is designed to include a second line segment, which is equivalent to adding a smooth plane structure at the bottom of the tube body, simplifying the mold structure of the press molding, and facilitating the welding and fixing of the heating tube to the outer bottom surface of the inner tank, which can simultaneously meet the fixing requirements of brazing and high-frequency welding for the heating tube; the length of the second line segment is greater than or equal to the length of the first line segment, which can control the overall height dimension of the heating tube, and tends to increase the radial width dimension, which is conducive to more concentrated heating of the bottom of the inner tank and improves the heating efficiency.

[0012] Furthermore, the length of the first arc is L1, the circumference of the outer surface of the tube body on the longitudinal section of the heating tube is L, and L1 / L=0.35-0.45.

[0013] By adopting the above technical solution, the ratio of the contact area between the heating tube and the inner tank to the outer surface area of the heating tube can be increased to more than 35%.

[0014] Furthermore, the distance S between the vertex of the second arc and the first arc is 6 mm to 9 mm.

[0015] The above-mentioned technical solution is adopted to ensure that the tube body is not damaged during one-time molding, and at the same time, the heating wire can be close to the second curved surface during the pressing process, meeting the design requirements.

[0016] Furthermore, the radius R of the second arc is ≤8 mm.

[0017] If the curved transition surface is too smooth, meaning the radius R of the second arc is too large, the outer side and bottom surfaces will become too narrow, and the longitudinal cross-section of the tube will tend to be rectangular. The heating wire cannot move away from the curved transition surface to approach the second curved surface. Avoiding an excessively large R also ensures sufficient distance between the heating wire and the inner wall of the tube, ensuring a tight filling of the thermal conductive material, ensuring the electrical strength of the heating tube, and improving safety.

[0018] Furthermore, the central area of the outer bottom surface of the inner container has a first plane, and the outer bottom surface is parallel to the first plane.

[0019] By adopting the above technical solution, the outer bottom surface can be used as a reference surface when fixing the heating tube before welding, which makes the welding process more convenient and helps to ensure the fit between the second curved surface and the first curved surface.

[0020] Furthermore, the outer bottom surface is higher than the first plane and the vertical distance to the first plane is H1, the vertical distance from the outer bottom surface to the vertex of the outer surface of the tube body is H2, and H1 / H2=0.4-0.6.

[0021] By adopting the above-mentioned technical solution, on the one hand, the heating tube is ensured to be suspended in the air to avoid affecting the installation of other components at the bottom of the inner tank. At the same time, H2 is referred to to control the fixed position H1 of the heating tube in the height direction. The heating tube is fixed at a suitable position on the bottom of the inner tank to control the size and height position of the second curved surface and the first curved surface. While ensuring heating efficiency, it can also reduce noise during heating.

[0022] Furthermore, the inner liner includes a liner body and a heat-conducting bowl arranged on the outside of the bottom of the liner body. The first curved surface is arranged on the outer surface of the heat-conducting bowl. The height of the heat-conducting bowl is H. The vertical distance from the outer bottom surface to the vertex of the outer surface of the tube body is H2, and H2 / H=0.0.4~0.65.

[0023] The above technical solution is adopted to ensure uniform heat conduction of the heat-conducting bowl and improve heating efficiency.

[0024] Furthermore, the outer bottom surface is higher than the first plane and the vertical distance to the first plane is H1. The inner liner includes a liner body and a heat-conducting bowl arranged on the outside of the bottom of the liner body. The first curved surface is arranged on the outer surface of the heat-conducting bowl. The upper edge of the heat-conducting bowl is higher than the vertex of the outer surface of the tube body and the vertical distance to the vertex of the outer surface of the tube body is H3, H3≤H1.

[0025] By adopting the above-mentioned technical solution, the heating tube is fixed relative to the heat-conducting bowl as close to the upper edge of the heat-conducting bowl as possible, achieving a certain degree of balance between improving heating efficiency and reducing heating noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of a liquid heater according to the present invention;

[0028] Figure 2 It is a schematic diagram of the longitudinal section of the heating tube in the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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.

[0030] The terms "first," "second," and so on (if any) in the specification and claims of this utility model are used to distinguish similar objects, not to describe a specific order or precedence. Even if "second" is used before a technical feature to distinguish it, it does not necessarily imply the presence of "first." It should be understood that in this utility model, "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. It should be understood that in this utility model, "plurality" refers to two or more. "And / or" is merely a description of an association between related objects, indicating that three relationships can exist. For example, "X and / or Y" can mean: X exists alone, X and Y exist simultaneously, or Y exists alone. The character " / " generally indicates that the related objects are in an "or" relationship. "Including X, Y, and Z" means that all three of X, Y, and Z are included. "Including X, Y, or Z" means that one of X, Y, and Z is included. "Including X, Y, and / or Z" means that any one, any two, or any three of X, Y, and Z are included.

[0031] The following specific embodiments are used to describe the technical solution of the present invention in detail. The following specific embodiments can be combined or replaced with each other according to actual conditions, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0032] like Figure 1As shown, the utility model provides a liquid heater, including an inner tank 100 and a heating tube 200, an outer shell 300 is provided on the outer side of the inner tank 100 to form a kettle body, the outer shell 300 generally has a handle 31, and a thermostat 400 is provided in the central area of the outer bottom surface of the inner tank 100. The liquid heater generally also includes a power base 500, and a power socket 600 is provided on the top of the power base 500. The kettle body is placed on the power base 500 so that the thermostat 400 and the power socket 600 are plugged and electrically coupled. The outer bottom surface of the inner tank 100 has a first curved surface 101 convex outward, and the heating tube 200 is fixed to the first curved surface 101, which can achieve a noise reduction effect during the heating process. For specific content, please refer to CN118141236A, which will not be repeated here. Figure 2 The heating tube 200 includes a tube body 21, a heat conductive material 22 and a heating wire 23. The tube body 21 is sleeved on the outside of the heating wire 23. The heat conductive material 22 is filled between the heating wire 23 and the tube body 21. Magnesium oxide powder can be used. The outer surface of the tube body 21 includes a second curved surface 201, an outer side surface 202, an outer bottom surface 203 and a curved transition surface 204. From the overall appearance of the tube body 21, the second curved surface 201, the outer side surface 202, the outer bottom surface 203 and the curved transition surface 204 all extend along the length direction of the tube body 21. Generally, the heating tube 200 will be bent into a C-shaped structure. There is also an existing technology that bends the heating tube 200 into a spiral structure or an S-shaped structure. The second curved surface 201 is concave toward the tube body 21 and is aligned with the first curved surface. The first curved surface 101 is aligned with the second curved surface 201, and the curved transition surface 204 is convex outward and away from the first curved surface 101 relative to the second curved surface 201. The intersection lines of the second curved surface 201, the outer side surface 202, the outer bottom surface 203, and the curved transition surface 204 with the longitudinal section of the heating tube 200 are the first arc 201A, the first curve 202A, the second curve 203A, and the second arc 204A, respectively. The first arc is located between the first and second curves, and the second arc is located between the first and second curves. The length of the first arc is greater than the lengths of the first, second, and second curves. The distance S1 from the heating wire 23 to the second curved surface 201 is, and the distance S2 from the heating wire 23 to the vertex of the curved transition surface 204 is, where S1 is less than half of S2. The liquid heater can be used for common functions such as boiling water, making tea, and warming milk.

[0033] In the present invention, in order to adapt to the first curved surface 101, the longitudinal section of the tube body 21 of the heat pipe 200 adopts a structure close to a triangle, wherein the length L1 of the first arc is greater than the length of the first curve, the second curve and the second arc L4, which is equivalent to the longest side of the triangle contacting and fitting the first curved surface 101, so that the ratio of the contact area between the heat pipe 200 and the inner tank 100 to the surface area of the heat pipe 200 can be increased to more than 35%. For example, the longitudinal section of the heat pipe 200 adopts a right triangle structure with a side length of 3:4:5, and the surface where the hypotenuse is located fits the first curved surface 101. The ratio of the contact area between the heating element 200 and the inner liner 100 to the outer surface area of the heating tube 200 can be increased to about 42%. If the longitudinal cross-section of the heating tube 200 adopts an obtuse triangle structure, this ratio can be further increased to about 45%. This not only increases the ratio of the heat energy generated by the heating tube 200 during operation and conducted to the inner liner 100, but also reduces the radiation loss of the heat energy generated by the heating tube 200 during operation. At the same time, by controlling S1 to be less than half of S2, that is, the heating wire 23 is closer to the inner liner 100, the heat energy generated by the heating tube 200 during operation can be conducted to the inner liner 100 faster and more effectively, thereby improving the thermal efficiency of the heating tube 200.

[0034] To further increase the length of the first curved line and make the heat pipe 200 more closely resemble an obtuse triangle, thereby facilitating uniform heating of the liquid in the inner pot 100 by the heat pipe 200, in one embodiment, the first curved line can be designed to include a first line segment that slopes outward from bottom to top relative to the outer bottom surface 203. Furthermore, the heat pipe 200 is typically formed by enclosing the heating wire 23 in a circular tube, filling it with a heat-conductive material 22, and then pressing it into shape using a mold. The outer surface of the tube body 21 is designed to have the aforementioned shape. During the pressing process, the mold's force applied to the tube body 21 is transferred to the heating wire 23 within. This not only allows the heating wire 23 to approach the second curved surface 201, ensuring that the design requirement of S1 being less than half of S2 is met, but also allows the shape of the heating wire 23 projected onto the longitudinal cross-section to resemble the longitudinal cross-section of the tube body 21. This increases the length of heat transfer from the heating wire 23 to the second curved surface 201, thereby improving heating efficiency. Furthermore, the outward slope of the first line segment from bottom to top relative to the outer bottom surface 203 also facilitates demolding after pressing.

[0035] In order to simplify the mold structure for press molding and facilitate welding and fixing the heating tube 200 to the outer bottom surface 203 of the inner tank 100, a second curve can be designed to include a second line segment, which is equivalent to adding a smooth plane structure to the bottom of the tube body 21, which can simultaneously meet the fixing requirements of brazing and high-frequency welding for the heating tube 200. At the same time, the angle C between the second line segment and the first line segment can be controlled to be ≥92°, for example, C = 92°, 95°, 100°, 108°, etc., which is conducive to demolding the heating tube 200 after press molding. Although a larger C makes the longitudinal cross-section of the tube body 21 flatter, which is beneficial to improving the efficiency of heat conduction, it may also cause the angles between the second curved surface 201 and the outer side surface 202, and the angles between the second curved surface 201 and the outer bottom surface 203 to be too small. Even if the tube body 21 is generally made of aluminum with good ductility, the tube body 21 is easily damaged by excessive compression deformation. Therefore, C should be controlled within a reasonable range. If the thickness of the tube body 21 is large, C can be controlled within 110°.

[0036] In one embodiment, the length M2 of the second line segment is greater than or equal to the length M1 of the first line segment, which can control the overall height of the heating tube 200 and tend to increase the radial width, which is conducive to more concentrated heating of the bottom of the inner tank 100 and improves heating efficiency.

[0037] The length of the first arc is L1, and the circumference of the outer surface of the tube body 21 on the longitudinal section of the heat pipe 200 is L. In one embodiment, L1 / L can be limited to 0.35-0.45, for example, 0.35, 0.38, 0.4, 0.42, 0.45, etc., to ensure that the ratio of the contact area between the heat pipe 200 and the inner container 100 to the outer surface area of the heat pipe 200 can be increased to more than 35%.

[0038] To properly control the flat structure of the tube body 21, the spacing S from the vertex of the second arc to the first arc is 6mm to 9mm, for example, S = 6mm, 7mm, 8mm, 9mm, etc. This ensures that the tube body 21 is not damaged during the first molding process, while also allowing the heating wire 23 to approach the second curved surface 201 during the molding process, meeting the design requirements. Specifically, the mold design ensures that both the second curved surface 201 and the curved transition surface 204 meet the aforementioned requirements. If S is too small, the longitudinal cross-section of the tube body 21 will be too flat, which can easily cause the guide surface to reversely squeeze the tube body 21, resulting in tube body 21 rupture. If S is too large, it will be difficult for the heating wire 23 to meet the requirement of approaching the second curved surface 201 during the molding process.

[0039] After the heat pipe 200 is press-formed, the heating wire 23 is required to be relatively away from the curved transition surface 204. If the curved transition surface 204 is too smooth, that is, the radius R of the second arc is too large, the outer side surface 202 and the outer bottom surface 203 will be too narrow, and the longitudinal cross-section of the tube body 21 will tend to be rectangular. The heating wire 23 cannot move away from the curved transition surface 204 to approach the second curved surface 201. It is understandable that the tube body 21 is originally a circular tube. R can be reduced but will not disappear. When R is selected as a larger value, press forming is easier. Therefore, a reasonable value within the aforementioned range can be selected, and the radius R of the second arc is controlled to be ≤8mm, for example, R = 8mm, 7mm, 6mm, 5mm, 4mm, or 2mm, etc., to avoid R being too large. It can also ensure that there is sufficient distance between the heating wire 23 inside the tube body 21 and the inner wall surface of the tube body 21 to ensure that the thermal conductive material 22 is tightly filled, thereby ensuring the electrical strength of the heat pipe 200 and improving safety.

[0040] In the prior art, in order to install a thermostat, the central area of the outer bottom surface 203 of the inner tank 100 is designed to have a first plane 102. In order to provide a reference surface when welding and fixing the heating tube 200, the outer bottom surface 203 can be selected to be parallel to the first plane 102. The outer bottom surface 203 can be used as a reference surface when fixing the heating tube 200 before welding. This makes the welding process more convenient and helps to ensure the fit between the second curved surface 201 and the first curved surface 101.

[0041] The outer bottom surface 203 is higher than the first plane 102, and the vertical distance from the outer bottom surface 203 to the first plane 102 is H1. The vertical distance from the outer bottom surface 203 to the vertex of the outer surface of the tube body 21 is H2. H1 / H2 = 0.4 to 0.6, for example, 0.4, 0.45, 0.5, 0.56, or 0.6, etc. On the one hand, it ensures that the heating pipe 200 is suspended in the air to avoid affecting the installation of other components at the bottom of the inner pot 100. At the same time, the fixed position H1 of the heating pipe 200 in the height direction is controlled with reference to H2. The heating pipe 200 is fixed at an appropriate position on the bottom of the inner pot 100 to control the size and height position of the second curved surface 201 in contact with the first curved surface 101. While ensuring heating efficiency, it can also reduce noise during heating. As analyzed above, due to the thickness of the tube body 21 and the ductility of the material, it is difficult to make the length of the first arc very long, so H2 cannot be very large. If H1 / H2 is too small, generally H1 is too small, that is, the fixed position of the heating tube 200 is too low. Due to the curved structure of the bottom of the inner tank 100, the closer the water level is to the inner bottom surface, the less water there is, and the greater the noise during direct heating. If H1 / H2 is too large, that is, the fixed position of the heating tube 200 is too high, more cold water will need to be heated from the beginning, and the effect of the curved bottom structure of the inner tank 100 on improving the heating efficiency will be reduced.

[0042] In order to improve heating uniformity, the inner liner 100 is generally designed to include a liner body 11 and a heat-conducting bowl 12 provided on the outside of the bottom of the liner body 11. The first curved surface 101 is provided on the outer surface of the heat-conducting bowl 12. The height dimension of the heat-conducting bowl 12 can be recorded as H, and the vertical distance from the outer bottom surface 203 to the vertex of the outer surface of the tube body 21 is recorded as H2. The dimension of H in the height direction is determined by associating H2, H2 / H=0.0.4~0.65, for example, 0.4, 0.45, 0.5, 0.56, 0.6 or 0.65, etc. The size of H is reasonably selected to ensure uniform heat conduction of the heat-conducting bowl 12 and improve heating efficiency. If H2 / H is too small, that is, H is too large, the heat conduction effect of the portion of the heat-conducting bowl 12 that is higher than the heat pipe 200 will be significantly reduced. When heating begins, the heat pipe 200 needs to heat the heat-conducting bowl 12 (which has a lower temperature) first, which can easily cause heat energy loss and affect heating efficiency. If H2 / H is too large, that is, H is too small, the contact area between the heat-conducting bowl 12 and the body 11 will be reduced, and the uniformity of heat conduction will be reduced.

[0043] The top edge of the heat-conducting bowl 12 is higher than the vertex of the outer surface of the tube body 21, and the vertical distance from the vertex to the outer surface of the tube body 21 is H3. In addition to limiting the height dimension H of the heat-conducting bowl 12, it can also be associated with H1, controlling H3 ≤ H1. This means that the heat pipe 200 is fixed as close to the top edge of the heat-conducting bowl 12 as possible, achieving a certain balance between improving heating efficiency and reducing heating noise.

[0044] In addition to the above-mentioned preferred embodiments, the present invention has other implementation methods. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection requested by the present invention.

Claims

1. A liquid heater, comprising an inner container and a heating tube, wherein the outer bottom surface of the inner container has a first curved surface convex outward, the heating tube is fixed to the first curved surface, the heating tube comprises a tube body, a heat conductive material and a heating wire, the tube body is sleeved on the outer side of the heating wire, and the heat conductive material is filled between the heating wire and the tube body, characterized in that: The outer surface of the tube body includes a second curved surface, an outer side surface, an outer bottom surface and a curved transition surface. The second curved surface is concave inside the tube body and fits into the first curved surface. The curved transition surface is convex outward and is away from the first curved surface relative to the second curved surface. The intersection lines of the second curved surface, the outer side surface, the outer bottom surface and the curved transition surface with the longitudinal section of the heating tube are the first arc, the first curve, the second curve and the second arc respectively. The first arc is located between the first curve and the second curve, and the second arc is located between the first curve and the second curve. The length of the first arc is greater than the lengths of the first curve, the second curve and the second arc. The distance from the heating wire to the second curved surface is S1, and the distance from the heating wire to the vertex of the curved transition surface is S2. S1 is less than half of S2.

2. The liquid heater according to claim 1, characterized in that The first curve includes a first line segment, and the first line segment is inclined outward from bottom to top relative to the outer bottom surface.

3. The liquid heater according to claim 2, characterized in that The second curve includes a second line segment, and an included angle C between the second line segment and the first line segment is ≥92°; and / or the second curve includes a second line segment, and a length of the second line segment is greater than or equal to a length of the first line segment.

4. The liquid heater according to claim 1, wherein The length of the first arc is L1, the circumference of the outer surface of the tube body on the longitudinal section of the heating tube is L, and L1 / L=0.35-0.

45.

5. The liquid heater according to claim 1, wherein The distance S from the vertex of the second arc to the first arc is 6 mm to 9 mm.

6. The liquid heater according to claim 5, characterized in that The radius R of the second arc is ≤8 mm.

7. The liquid heater according to claim 1, wherein The central area of the outer bottom surface of the inner container has a first plane, and the outer bottom surface is parallel to the first plane.

8. The liquid heater according to claim 7, characterized in that The outer bottom surface is higher than the first plane and the vertical distance to the first plane is H1. The vertical distance from the outer bottom surface to the vertex of the outer surface of the tube body is H2, and H1 / H2=0.4-0.

6.

9. The liquid heater according to claim 7, characterized in that The inner liner includes a liner body and a heat-conducting bowl arranged on the outside of the bottom of the liner body. The first arc surface is arranged on the outer surface of the heat-conducting bowl. The height of the heat-conducting bowl is H. The vertical distance from the outer bottom surface to the vertex of the outer surface of the tube body is H2, and H2 / H=0.0.4~0.

65.

10. The liquid heater according to claim 7, wherein The outer bottom surface is higher than the first plane and the vertical distance to the first plane is H1. The inner liner includes a liner body and a heat-conducting bowl arranged on the outside of the bottom of the liner body. The first curved surface is arranged on the outer surface of the heat-conducting bowl. The upper edge of the heat-conducting bowl is higher than the vertex of the outer surface of the tube body and the vertical distance to the vertex of the outer surface of the tube body is H3, H3≤H1.

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