An electric water heater and a flow channel structure and a heater thereof

Abstract

The application discloses an electric water heater and a flow channel structure and a heater thereof. The flow channel structure comprises an upper flow channel base body and a lower flow channel base body which are stacked together and jointly hold a heating element. The base bodies are provided with recessed flow channel grooves on the side away from the heating element, and the stacked base bodies form a spiral water flow channel around the heating element. The side towards the heating element is respectively attached to upper and lower sealing cover plates to form an independent heating element mounting cavity. The water flow channel and the mounting cavity are arranged on the two sides of the sealing cover plate, thereby reducing the heat transfer interface, significantly reducing the contact thermal resistance, and improving the thermal efficiency. Meanwhile, the heating element is convenient to disassemble, maintain and assemble. The structure does not need a die-casting aluminum base body, effectively avoids the cracking and water leakage risk caused by shrinkage, air bubbles, thermal fatigue or corrosion, and has high reliability and manufacturing simplicity.

Description

Technical Field

[0001] This application relates to the technical field of electric water heaters, specifically to an electric water heater and its flow channel structure and heater technology. Background Technology

[0002] Currently, the mainstream heating element solution for instant water heater modules generally adopts a composite structure of "die-cast aluminum substrate + pre-embedded stainless steel water pipe". Heat needs to be transferred from the heating element to the water flow, and must pass through two contact interfaces in sequence: the heating element, the aluminum substrate, and the stainless steel water pipe.

[0003] At this point, a gap thermal resistance inevitably exists between these two interfaces. Furthermore, the die-casting aluminum process itself is prone to introducing defects such as shrinkage cavities and bubbles, leading to significant heat loss and making it difficult to improve the overall thermal efficiency of the machine. Simultaneously, the difference in thermal expansion coefficients between aluminum and stainless steel generates alternating stress under repeated hot and cold cycles. This not only accelerates the compaction of magnesium oxide powder within the heating element, causing wire breakage, but also causes the aluminum matrix to crack due to thermal fatigue, resulting in a fatal risk of water leakage. In addition, aluminum alloys have insufficient corrosion resistance in hard water or corrosive environments, and long-term use easily leads to pitting and perforation. Moreover, the high cost of molds and fluctuations in raw material prices also constrain product cost optimization.

[0004] To avoid the problems associated with die-cast aluminum, the industry has also experimented with a "stainless steel cup" instant heating structure, in which the heating element is directly immersed in a small stainless steel inner tank. However, this method allows water to come into direct contact with the heating element, making it extremely easy for scale to form quickly on the high-temperature surface. This not only reduces heat exchange efficiency, but the accumulation of scale can also exacerbate localized corrosion, resulting in the same drawbacks of short lifespan and easy leakage.

[0005] Therefore, the electric water heater industry has a need for a flow channel structure and heater for instant heating modules that can improve interfacial thermal resistance, avoid material corrosion, and simplify the manufacturing process. Summary of the Invention

[0006] This application proposes an electric water heater and its flow channel structure and heater. By optimizing the flow channel structure, the thermal efficiency is improved while addressing the problems existing in the current die-cast aluminum substrate solution.

[0007] To achieve the above objectives, the present application adopts the following technical solution: In a first aspect, this application proposes a flow channel structure for an electric water heater, comprising: The upper flow channel substrate and the lower flow channel substrate are stacked on top of each other and together clamp the heating element; The upper flow channel base and the lower flow channel base are respectively provided with recessed flow channel grooves on the side away from the heating element. When the upper flow channel base and the lower flow channel base are superimposed, the flow channel grooves of the two are joined to form a spiral water flow channel arranged around the heating element. It also includes an upper sealing cover plate and a lower sealing cover plate. The upper sealing cover plate is attached to the side of the upper flow channel substrate facing the heating element, and the lower sealing cover plate is attached to the side of the lower flow channel substrate facing the heating element. The upper sealing cover plate and the lower sealing cover plate are attached to each other at the left and right ends, and form an installation cavity in the middle for accommodating the heating element. The spiral-shaped closed water flow channels are interconnected on both sides of the mounting cavity.

[0008] Thus, by setting flow channel grooves on the side of the upper and lower flow channel substrate away from the heating element and attaching a sealing cover plate to the inner side facing the heating element, the water flow channel and the heating element mounting cavity are respectively located on both sides of the sealing cover plate. This not only reduces the heat transfer interface between the aluminum substrate and the water pipe in the traditional solution, significantly reducing contact thermal resistance and improving thermal efficiency, but also places the heating element in an independent mounting cavity formed by the sealing cover plate, which is convenient for disassembly and maintenance.

[0009] Meanwhile, the overall structure does not rely on the die-cast aluminum substrate, which fundamentally avoids the risk of cracking and leakage caused by shrinkage cavities, bubbles, thermal fatigue and corrosion, thus balancing high reliability and simplified manufacturing.

[0010] In some possible implementations, the upper flow channel substrate, the upper sealing cover, the lower flow channel substrate, and the lower sealing cover are all integrally formed by stamping stainless steel.

[0011] In some possible implementations, both the upper flow channel substrate and the lower flow channel substrate include substrate side edges located on the left and right sides of the heating element, and a substrate heating element groove formed between the substrate side edges on the side opposite to the heating element.

[0012] In some possible implementations, the upper sealing cover and the lower sealing cover are respectively formed with cover plate heating element grooves that match their contours at the positions corresponding to the heating element grooves in the substrate.

[0013] In some possible implementations, the flow channel is provided with a flow channel connector groove at the side edge of the substrate, so that after the upper flow channel substrate and the lower flow channel substrate are superimposed, their respective flow channel channels are interconnected through the flow channel connector groove to form a continuous spiral water flow channel.

[0014] In some possible implementations, the upper sealing cover and the lower sealing cover form a cover plate heating element groove at the corresponding position of the heating element groove in the substrate; Cover plate side edges are provided on both sides of the heating element recess in the cover plate, and the cover plate side edges are clamped and fixed by the base side edges; The cover plate has a flow channel docking hole at the position corresponding to the flow channel joint groove on its side edge.

[0015] In some possible implementations, the upper flow channel substrate, upper sealing cover, lower flow channel substrate, and lower sealing cover are formed by stamping from sheet metal of the same size; The upper and lower flow channel substrates are provided with substrate positioning holes, and the upper and lower sealing cover plates are provided with cover plate positioning holes at positions corresponding to the substrate positioning holes.

[0016] Secondly, this application proposes a heater including the flow channel structure described above; Also includes: Heating element disposed within the mounting cavity; Thermostat mounting bracket disposed on the upper or lower sealing cover plate, and thermostat mounted on the thermostat mounting bracket.

[0017] In some possible implementations, it also includes: The upper cover housing and the lower cover housing cover the upper flow channel base, and the lower cover housing covers the lower flow channel base. When the two are put together, they completely cover the flow channel structure and the heating element. The upper cover and lower cover are provided with limiting grooves on their end faces along the extension direction of the heating element for radially limiting the heating element.

[0018] Thirdly, this application also proposes an electric water heater that utilizes the flow channel structure described above. Attached Figure Description

[0019] Figure 1 This is an overall schematic diagram of the heater in this application; Figure 2 This is an exploded schematic diagram of the upper and lower cover shells of the heater in this application; Figure 3 This is an exploded schematic diagram of the flow channel structure in this application; Figure 4 These are the top view and cross-sectional view at point A of the flow channel structure in this application; Figure 5 yes Figure 4 Sectional view at point B in the top view; Figure 6 yes Figure 2 Enlarged view of a portion of point A in the middle; Figure 7 This is a schematic diagram showing the corresponding positioning holes and flow channel joint grooves of the flow channel structure in this application; Figure 8 This is a schematic diagram of the mounting cavity in this application; Figure 9 This is a cross-sectional view of the corresponding positions of the upper flow channel substrate and the upper sealing cover plate in this application. Detailed Implementation

[0020] The following examples further illustrate the features of this application and other related features in detail, so as to facilitate understanding by those skilled in the art: It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions in the attached diagrams, while the terms “bottom surface,” “top surface,” “inner,” and “outer” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0021] Furthermore, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this case based on the specific circumstances.

[0022] Currently, most mainstream electric water heaters on the market use a die-cast aluminum substrate as the instant heating module, with stainless steel water pipes pre-embedded during the die-casting process to form a water flow channel. However, the die-cast aluminum used in this solution has three significant defects as a material for the process.

[0023] First, the die-casting aluminum process itself is limited by the metal's fluidity and solidification shrinkage characteristics, making it prone to casting defects such as shrinkage cavities, porosity, and cold shuts in complex flow channels. These internal defects not only weaken the structural strength and become potential crack sources, but also accelerate thermal fatigue cracking under long-term alternating hot and cold conditions, especially in high water pressure or frequent start-stop scenarios, significantly increasing the risk of water leakage.

[0024] Secondly, to achieve water flow isolation, stainless steel water pipes must be pre-embedded within the aluminum substrate, thus forming a multi-layered heat transfer path: "heating element – ​​aluminum substrate – stainless steel pipe – water flow". Due to differences in surface roughness, assembly tolerances, and thermal expansion, microscopic gaps inevitably exist between aluminum and stainless steel, creating significant contact thermal resistance. This interface drastically reduces overall thermal conductivity, making it difficult to overcome the bottleneck in overall machine thermal efficiency. Simultaneously, it forces the heating element 10 to operate at higher power, further exacerbating localized overheating and lifespan reduction.

[0025] Third, most existing die-cast aluminum heating elements are completely enclosed, one-piece structures. The heating element 10 and the stainless steel water pipe are permanently encased inside the aluminum substrate and cannot be disassembled or replaced separately. Once the heating element 10 ages and fails, or the stainless steel pipe is perforated due to corrosion, the entire heating module becomes unusable, and users can only return the whole machine for repair or replacement, which greatly increases after-sales costs and wastes resources.

[0026] Furthermore, die-cast aluminum solutions require extremely high mold precision, and the development cycle for a complete mold is long and costly. Moreover, because casting yield is greatly affected by material batches and process parameters, the scrap rate in actual production is relatively high, further increasing the cost per unit. In the current highly competitive and cost-sensitive market environment of the home appliance industry, this type of high-investment, low-maintainability structure can no longer meet the needs of product iteration and long-term user use.

[0027] To circumvent the inherent defects of die-cast aluminum substrates, another technical approach in the industry is to use a "stainless steel cup" type instant heating structure, in which the heating element 10 is directly immersed in a closed small stainless steel cavity, and the water is heated in the cavity before being output. However, this type of structure is essentially still a micro-storage water heating mode, rather than a true instantaneous flow heat exchange.

[0028] The fundamental problem lies in the fact that during the heating process, the water remains stagnant within the sealed cavity for an extended period, directly contacting the surface of the high-temperature heating element 10. In areas where the local temperature exceeds 60°C, calcium and magnesium ions in the water readily precipitate, forming dense scale that adheres to the heating surface. This not only causes a continuous decline in heat exchange efficiency, but more seriously, the structure cannot achieve complete drainage and flushing of the water, leading to the continuous accumulation of scale that is difficult to remove. After prolonged use, the stagnant water remaining in the cavity is repeatedly heated, violating the healthy water usage concept of instantaneous water heaters: heat only what is used, and ensure fresh, flowing water throughout the process. Moreover, the scale layer not only significantly reduces heat exchange efficiency but also induces under-deposit corrosion, similarly leading to a shortened lifespan and the risk of leaks.

[0029] Therefore, although stainless steel cups are superior to die-cast aluminum in terms of material corrosion resistance, they still have significant shortcomings in terms of water health, structural reliability, and maintainability.

[0030] To address the aforementioned technical challenges, this application proposes a flow channel structure for electric water heaters, which physically isolates the water flow channel from the heating element 10 mounting cavity, and achieves a highly efficient, reliable, and easy-to-assemble structure through all-metal stamping parts. The electric water heater includes those equipped with an instant heating module, specifically including instantaneous electric water heaters and dual-mode electric water heaters that combine storage heating and instantaneous heating modes. The instant heating module refers to a functional unit capable of instantly heating the flowing water.

[0031] Please refer to the details. Figures 3 to 5 as well as Figure 8The flow channel structure includes an upper flow channel base 1 and a lower flow channel base 3, which are stacked one on top of the other and together hold the heating element 10. The upper flow channel base 1 and the lower flow channel base 3 each have a recessed flow channel groove 104 on the side opposite to the heating element 10. When the upper flow channel base 1 and the lower flow channel base 3 are stacked, their flow channel grooves 104 align to form a spiral water flow channel surrounding the heating element 10. The structure also includes an upper sealing cover plate 2 and a lower sealing cover plate 4: the upper sealing cover plate 2 is attached to the side of the upper flow channel base 1 facing the heating element 10, and the lower sealing cover plate 4 is attached to the side of the lower flow channel base 3 facing the heating element 10. The upper sealing cover plate 2 and the lower sealing cover plate 4 are attached to each other at their left and right ends, forming a mounting cavity 100 in the middle to accommodate the heating element 10. The spiral closed water flow channel is interconnected on both sides of the mounting cavity 100, forming a continuous inlet-outlet flow path.

[0032] At this time, the lower flow channel base 3 is provided with a water inlet connector 31, and the upper flow channel base 1 is provided with a water outlet connector 11, which are used to connect the external water supply pipe and the water outlet pipe, respectively. It should be noted that the specific arrangement of the water inlet connector 31 and the water outlet connector 11 is not limited to the structure shown in this embodiment, and can be adapted to the overall layout or flow channel design requirements.

[0033] Therefore, the water flows only within the closed channel formed by the flow channel 104, without direct contact with the heating element 10, fundamentally avoiding scaling and under-deposit corrosion problems. Heat is directly conducted to the water flow through the metal walls of the upper sealing cover 2 and the lower sealing cover 4, eliminating the additional interface of the "aluminum-stainless steel" water pipe in traditional solutions, significantly reducing contact thermal resistance and improving overall thermal efficiency. More importantly, the heating element 10 is independently encapsulated within the mounting cavity 100, facilitating later disassembly and replacement, greatly improving maintenance convenience.

[0034] The heating element 10 used to heat the water flow can be selected from resistance heating tubes, PTC (positive temperature coefficient) ceramic heaters, thick-film or thin-film printed heating elements, and electromagnetic induction coils that can be used under specific designs. All of the above heating elements can convert electrical energy into heat energy and can be selected according to product positioning, cost, and performance requirements.

[0035] In this embodiment, the heating element 10 is preferably an electric heating tube. As a mature and reliable heating element, the electric heating tube has advantages such as high power density, fast thermal response, low manufacturing cost, and ease of mechanical assembly and heat conduction with the stainless steel flow channel substrate. Its cylindrical structure is particularly well-suited to the spiral water flow channel constructed in this application, ensuring efficient and uniform heat transfer to the flowing water, thereby guaranteeing high thermal efficiency while also considering product reliability and ease of production.

[0036] In terms of material selection, the upper flow channel substrate 1, upper sealing cover plate 2, lower flow channel substrate 3, and lower sealing cover plate 4 are preferably all integrally formed from stainless steel by stamping. Stainless steel not only has excellent corrosion resistance and is suitable for various water quality environments, but also, as in this embodiment, when the heating element 10 is an electric heating tube, its coefficient of thermal expansion is closer to that of commonly used electric heating tube outer tubes (usually also made of stainless steel), which can effectively alleviate the alternating stress caused by the difference in thermal expansion and contraction, thereby avoiding the problems of excessive compaction of magnesium oxide powder and breakage of the heating wire. Of course, in specific cost-sensitive scenarios, aluminum alloys or copper alloys with better corrosion resistance can also be selected as alternative materials, but considering both reliability and lifespan, stainless steel is still the first choice.

[0037] The following is a detailed explanation of the flow channel structure. Please refer to [link / reference]. Figures 3 to 6 as well as Figure 9 Both the upper flow channel substrate 1 and the lower flow channel substrate 3 include substrate side edges 102 located on the left and right sides of the heating element 10, and substrate heating element grooves 103 formed between the substrate side edges 102 on the side away from the heating element 10. The "left and right" direction mentioned herein refers to the radial arrangement direction when multiple heating elements 10 are arranged side-by-side using heating tubes as heating elements 10. Correspondingly, the upper sealing cover plate 2 and the lower sealing cover plate 4 form cover plate heating element grooves 203 that match their contours at positions corresponding to the substrate heating element grooves 103. Thus, when the upper sealing cover plate 2 is attached to the upper flow channel substrate 1 and the lower sealing cover plate 4 is attached to the lower flow channel substrate 3, the heating element groove 203 of the cover plate and the heating element groove 103 of the substrate can be precisely attached, which can stably seal the flow channel groove 104. After the attachment, the upper and lower cover plate heating element grooves 203 together form a complete mounting cavity 100, ensuring that the heating element 10 is stably wrapped.

[0038] Furthermore, to achieve continuous flow of the spiral water channel, the flow channel 104 is provided with a flow channel connector groove 105 at the side edge 102 of the base. When the upper flow channel base 1 and the lower flow channel base 3 are superimposed, their respective flow channel grooves 104 are interconnected through the flow channel connector groove 105, forming a spiral water flow path with the beginning and end connected. At the same time, the upper sealing cover plate 2 and the lower sealing cover plate 4 are provided with cover plate side edges 202 on both sides of the cover plate heating element groove 203. The cover plate side edges 202 are clamped and fixed by the base side edges 102, thereby enhancing the overall structural rigidity; and the cover plate side edges 202 are provided with flow channel docking holes 204 at the corresponding positions of the flow channel connector groove 105 to ensure that the flow channel connector groove 105 is not blocked and to maintain smooth water flow.

[0039] It should be noted that the main function of the upper sealing cover 2 and the lower sealing cover 4 is to partially seal the flow channel groove 104 in the mounting cavity 100 area, that is, to seal the flow channel groove 104 only at the corresponding heating element 10 mounting position to prevent water from entering the mounting cavity 100. Therefore, the sealing cover is a solid plate structure in the area where the cover plate heating element recess 203 is located, while it may not be covered in other areas. Accordingly, in some embodiments, the upper sealing cover 2 and the lower sealing cover 4 may only achieve partial contact sealing on the left and right sides of the mounting cavity 100, without extending to the side edge 102 of the base. In this configuration, the flow channel joint groove 105 on the upper flow channel base 1 and the lower flow channel base 3 can be directly aligned and connected, without the need for the side edge 202 of the cover.

[0040] Furthermore, the effectiveness of the flow channel structure in this application depends on the accuracy of its flow channel docking. For this, please refer to the references... Figure 3 and Figure 7 To simplify manufacturing and assembly, the upper flow channel substrate 1, upper sealing cover plate 2, lower flow channel substrate 3, and lower sealing cover plate 4 can be stamped from sheet metal of the same size. Based on this, the upper flow channel substrate 1 and lower flow channel substrate 3 are provided with substrate positioning holes 101, and the upper sealing cover plate 2 and lower sealing cover plate 4 are provided with cover plate positioning holes 201 at positions corresponding to the substrate positioning holes 101. During assembly, by aligning the substrate positioning holes 101 with the cover plate positioning holes 201, precise positioning of each component can be quickly achieved, especially accurate alignment of the flow channel connector groove 105, significantly improving production efficiency and ensuring sealing reliability.

[0041] Subsequently, the aforementioned plates are fixed using a step-by-step welding method. Preferably, the upper flow channel base 1 and the upper sealing cover plate 2 are first aligned and welded together to form the upper flow channel assembly, while the lower flow channel base 3 and the lower sealing cover plate 4 are simultaneously aligned and welded together to form the lower flow channel assembly. Then, the upper and lower flow channel assemblies are precisely joined along their mating surfaces and connected as a single unit through peripheral welding, ultimately forming a reliable all-metal integrated flow channel structure.

[0042] Please refer to Figure 1 and Figure 2 Based on the aforementioned flow channel structure, this application further provides a heater for an electric water heater. In addition to the aforementioned flow channel structure and the heating element 10 disposed within the mounting cavity 100, the heater also has a thermostat mounting bracket 21 on the upper sealing cover plate 2, on which a thermostat 20 is mounted to prevent the heating element 10 from overheating due to dry burning. A silicon controlled rectifier (SCR) mounting base 311 is also integrated near the water inlet connector 31 for mounting the SCR 30, enabling dual-point monitoring to ensure constant temperature performance and safety.

[0043] It should be noted that the thyristor 30 preferably uses a bidirectional thyristor (TRIAC) as the power control element. The thyristor 30 receives real-time temperature data from a water outlet temperature sensor (not shown in the figure; it is a common practice for electric water heaters to have a temperature sensor at the water outlet). The built-in microcontroller dynamically calculates the required heating power based on the deviation between the set temperature and the actual water temperature, and continuously and steplessly controls the power supply to the heating element 10 by adjusting the conduction angle of the bidirectional thyristor. This method can accurately match the heat load demand of the instantaneous variable flow rate of the electric water heater's instantaneous heating module, effectively avoiding sudden water temperature rises or overshoots, and significantly improving the stability of the outlet water temperature and the safety of use.

[0044] To further enhance the overall structural strength and positioning stability of the heating element 10, the heater also includes an upper cover shell 40 and a lower cover shell 50. The upper cover shell 40 covers the upper flow channel base 1, and the lower cover shell 50 covers the lower flow channel base 3. When the two are joined together, they completely enclose the entire flow channel structure and the heating element 10. The upper cover shell 40 and the lower cover shell 50 are connected and fixed by shell connecting ribs 42 to form a robust outer shell. At the same time, both are provided with limiting grooves 41 on the end faces along the extension direction of the heating element 10 for radially limiting the heating element 10, effectively preventing the heating element 10 from axial movement or radial displacement during transportation or use, ensuring that it is always in the optimal heat exchange position.

[0045] It should be noted that although no independent axial limiting component is provided in this embodiment, the axial length of the mounting cavity 100 formed by the upper flow channel base 1 and the lower flow channel base 3 is precisely matched with the total length of the heating element 10. Combined with the slight pre-tightening force applied to the internal components after the upper cover shell 40 and the lower cover shell 50 are assembled, the heating element 10 is reliably clamped in the axial direction, thereby effectively suppressing its axial movement. This setting method also facilitates the disassembly and maintenance of the heating element 10.

[0046] In addition, mounting ears 51 are provided on the outer side of the lower cover housing 50, which facilitates the quick fixing of the entire heater module into the electric water heater housing, improving the overall assembly efficiency.

[0047] In summary, this application, by physically isolating the water flow channel from the heating element 10, adopting an all-stainless steel stamping structure, optimizing the assembly positioning mechanism, and integrating multiple sensors and limit designs, not only completely avoids the problems of high thermal resistance, easy cracking, and poor corrosion resistance of the die-cast aluminum solution, but also overcomes the scaling and corrosion defects of the stainless steel cup body solution. At the same time, the modular design allows the heating element 10 to be replaced individually, significantly extending the product's service life; and the standardized stamping process effectively reduces manufacturing costs and mold investment.

[0048] As stated above, this case protects an electric water heater and its flow channel structure and heater. All technical solutions that are the same as or similar to this case should be considered to fall within the protection scope of this case.

Claims

1. A flow channel structure for an electric water heater, characterized in that, include: The upper flow channel substrate (1) and the lower flow channel substrate (3) are stacked on top of each other and together hold the heating element (10). The upper flow channel substrate (1) and the lower flow channel substrate (3) are respectively provided with recessed flow channel grooves (104) on the side away from the heating element (10). When the upper flow channel substrate (1) and the lower flow channel substrate (3) are superimposed, the flow channel grooves (104) of the two are joined to form a spiral water flow channel arranged around the heating element (10). It also includes an upper sealing cover plate (2) and a lower sealing cover plate (4). The upper sealing cover plate (2) is attached to the side of the upper flow channel substrate (1) facing the heating element (10), and the lower sealing cover plate (4) is attached to the side of the lower flow channel substrate (3) facing the heating element (10). The upper sealing cover plate (2) and the lower sealing cover plate (4) are attached to each other at the left and right ends, forming an installation cavity (100) in the middle for accommodating the heating element (10). The spiral water flow channels are interconnected on both sides of the mounting cavity (100).

2. The flow channel structure for an electric water heater as described in claim 1, characterized in that, The upper flow channel substrate (1), upper sealing cover plate (2), lower flow channel substrate (3) and lower sealing cover plate (4) are all integrally formed by stamping stainless steel.

3. The flow channel structure for an electric water heater as described in claim 1, characterized in that, The upper flow channel substrate (1) and the lower flow channel substrate (3) both include substrate side edges (102) located on the left and right sides of the heating element (10), and substrate heating element grooves (103) formed between the substrate side edges (102) on the side away from the heating element (10).

4. The flow channel structure for an electric water heater as described in claim 3, characterized in that, The upper sealing cover plate (2) and the lower sealing cover plate (4) respectively form cover plate heating element grooves (203) that match the contour of the corresponding heating element groove (103) of the substrate.

5. The flow channel structure for an electric water heater as described in claim 3, characterized in that, The flow channel (104) is provided with a flow channel connector groove (105) at the side edge (102) of the base body, so that after the upper flow channel base (1) and the lower flow channel base (3) are superimposed, their respective flow channel (104) are interconnected through the flow channel connector groove (105) to form a continuous spiral water flow channel.

6. The flow channel structure for an electric water heater as described in claim 5, characterized in that, The upper sealing cover plate (2) and the lower sealing cover plate (4) form a cover plate heating element groove (203) at the corresponding position of the heating element groove (103) of the substrate. Cover plate side edges (202) are provided on both sides of the cover plate heating element groove (203), and the cover plate side edges (202) are clamped and fixed by the base side edge (102); The cover plate side edge (202) has a flow channel docking hole (204) at the position corresponding to the flow channel joint groove (105).

7. The flow channel structure for an electric water heater as described in claim 5, characterized in that, The upper flow channel substrate (1), upper sealing cover plate (2), lower flow channel substrate (3) and lower sealing cover plate (4) are stamped from sheet metal of the same size; The upper flow channel substrate (1) and the lower flow channel substrate (3) are provided with substrate positioning holes (101), and the upper sealing cover plate (2) and the lower sealing cover plate (4) are provided with cover plate positioning holes (201) at positions corresponding to the substrate positioning holes (101).

8. A heater for an electric water heater, characterized in that, Including the flow channel structure for an electric water heater as described in any one of claims 1 to 7, further comprising: Heating element (10) disposed in the mounting cavity (100); Thermostat mounting bracket (21) is provided on the upper sealing cover plate (2) or the lower sealing cover plate (4), and thermostat (20) is installed on the thermostat mounting bracket (21).

9. A heater for an electric water heater as described in claim 8, characterized in that, Also includes: The upper cover housing (40) and the lower cover housing (50) cover the upper flow channel base (1) above and the lower cover housing (50) cover the lower flow channel base (3) below. When the two are put together, they will cover the flow channel structure and the heating element (10) as a whole. The upper cover housing (40) and the lower cover housing (50) are provided with limiting grooves (41) on the end faces of the heating element (10) extending in the direction of the heating element (10) for radially limiting the heating element (10).

10. An electric water heater, characterized in that, The flow channel structure for electric water heaters as described in any one of claims 1 to 7 is applied.

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