A heating assembly

Abstract

The utility model provides a kind of heating assembly, including metal shell and heating pipe, heating pipe is at least partially located in metal shell, metal shell has water inlet pipe;It further includes heat-absorbing plate, the heat-absorbing plate is assembled with the metal shell connection, metal shell and the water inlet pipe are simultaneously heat-conducting connection with heat-absorbing plate.Metal shell is equipped with temperature controller, temperature controller uses jump type temperature controller, its bimetallic temperature sensing sheet has convection space between the inner side wall of cover.The utility model in, the heat of metal shell is absorbed by heat-absorbing plate, and is taken away by cold water of water inlet pipe, cold water can absorb heat before entering heating assembly, reduce power consumption, improve thermal efficiency;In addition, bimetallic temperature sensing sheet of temperature controller and cover between temperature controller have convection space, hot air can quickly enter temperature controller inside, so that the temperature of bimetallic temperature sensing sheet surface quickly reaches the temperature set, and then bimetallic temperature sensing sheet is deformed and makes temperature controller disconnect power supply, effectively prevent dry burning.

Description

Technical Field

[0001] This utility model belongs to the field of heating element technology, and in particular relates to a heating assembly. Background Technology

[0002] Instantaneous heating components can heat a medium and have a wide range of applications, such as water dispensers, wall-mounted water heaters, and under-sink water dispensers, all of which use instantaneous heating components to heat water to meet drinking or other needs. In related technologies, instantaneous heating components with metal casings experience heat loss due to heat conduction to the metal casing and subsequent heat dissipation, resulting in reduced thermal efficiency. Summary of the Invention

[0003] In view of this, the present invention aims to overcome at least one of the problems in the prior art by providing a heating assembly.

[0004] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0005] A heating assembly includes a metal housing and a heating tube, the heating tube being at least partially located within the metal housing, the metal housing having a water inlet pipe; it also includes a heat-absorbing plate, the heat-absorbing plate being assembled and connected to the metal housing, the metal housing and the water inlet pipe being thermally connected to the heat-absorbing plate.

[0006] Compared with the prior art, this utility model has the following advantages:

[0007] The heating component described in this utility model involves cold water flowing into the heating component's heating tube through an inlet pipe. This heating tube heats the water flowing through the component, and some of the heat is transferred from the heating tube to the metal casing. Due to the heat exchange between the heat-absorbing plate and the metal casing through a thermally conductive connection, the heat-absorbing plate carries away some of the heat from the metal casing and transfers it to the inlet pipe. This preheats the cold water entering the inlet pipe, allowing the cold water to absorb a certain amount of heat before entering the heating component, thus improving the heating efficiency and energy-saving and environmentally friendly aspects of the heating component. Attached Figure Description

[0008] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0009] Figure 1 A schematic diagram of the heating component structure provided in an embodiment of this utility model;

[0010] Figure 2 This is a schematic diagram of the structure of the heating assembly provided in this embodiment of the present invention after the heating plate has been removed;

[0011] Figure 3 This is a schematic diagram of the structure of the heating plate of the heating assembly provided in an embodiment of the present utility model;

[0012] Figure 4 A schematic diagram of the structure of the heating component temperature controller provided in this embodiment of the utility model;

[0013] Figure 5 An exploded view of the heating assembly provided in an embodiment of this utility model.

[0014] Explanation of reference numerals in the attached figures:

[0015] 100. Metal casing; 110. Inlet pipe; 120. Outlet pipe; 130. Upper petal casing; 140. Lower petal casing; 150. Bottom of metal casing; 160. Side of metal casing; 170. Snap-fit ​​structure; 200. Heating tube; 300. Heat absorber plate; 310. Water inlet preheating section; 320. Main body; 330. Extension section; 400. Thermostat; 410. Bimetallic temperature sensor; 420. Cover; 500. Convection space. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments of the present invention can be combined with each other.

[0017] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0018] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Figure 1 See the schematic diagram of the heating component structure provided in this embodiment of the utility model. Figure 1 A heating assembly includes a metal casing 100 and a heating tube 200, with the heating tube 200 at least partially located within the metal casing 100. The metal casing 100 has a water inlet pipe 110. The heating assembly also includes a heat-absorbing plate 300, which is assembled and connected to the metal casing 100. Both the metal casing 100 and the water inlet pipe 110 are thermally connected to the heat-absorbing plate 300. The water inlet pipe 110 is used to introduce water to be heated (such as purified room-temperature drinking water) into the heating assembly. The heating effect of the heating tube 200 heats the water flowing into the water inlet pipe 110.

[0020] The heating component is also equipped with a metal shell 100. The metal shell 100 not only serves as an enclosure, but also utilizes the thermal conductivity of metal to facilitate the rapid dissipation of heat from the heating tube 200 into the air to the outside of the metal shell 100, thus avoiding adverse effects on the components of the heating component from prolonged high temperatures.

[0021] This utility model provides a heating component with a heat-absorbing plate 300 installed on a metal casing 100. The water preheating section 310 of the heat-absorbing plate 300 heats the cold water in the water inlet pipe 110, so that the heat absorbed by the heat-absorbing plate 300 is carried away by the cold water in the water inlet pipe 110. The cold water absorbs heat before entering the heating component, which can reduce the power consumption of the heating component to a certain extent and improve the instant heating efficiency of cold water. By using the heat-absorbing plate 300 to absorb the heat of the metal casing 100 and preheat the water in the water inlet pipe 110, it can not only effectively reduce the power consumption required by the heating element 200, but also reduce the heating time required for the water in the later stage, so that hot water that meets the outlet temperature requirements can quickly flow out of the heating component, improving the user experience. It also helps to quickly reduce the surface temperature of the metal casing 100, so that the heat inside the metal casing 100 can be quickly dissipated, ensuring that all components in the heating component are at a suitable ambient temperature, and effectively extending the service life of the heating component.

[0022] Optionally, a portion of the heat absorber plate 300 is arranged corresponding to the metal casing 100, and the portion of the heat absorber plate 300 arranged corresponding to the metal casing 100 is thermally connected to the metal casing 100. Another portion of the heat absorber plate 300 is arranged corresponding to the water inlet pipe 110, and the portion of the heat absorber plate 300 arranged corresponding to the water inlet pipe 110 is thermally connected to the water inlet pipe 110.

[0023] For example, see Figure 3 The heat-absorbing plate 300 includes an extension portion 330, a main body portion 320, and a water inlet preheating portion 310. The water inlet preheating portion 310 is located at the end of the main body portion 320 away from the extension portion 330. The portion of the heat-absorbing plate 300 that is thermally connected to the metal shell 100 is located in the extension portion 330, and the portion of the heat-absorbing plate 300 that is thermally connected to the water inlet pipe 110 is located in the water inlet preheating portion 310.

[0024] The main body 320 is disposed corresponding to the bottom 150 of the metal casing, and the extension 330 is disposed corresponding to the side 160 of the metal casing. Heat exchange occurs through the contact portion between the heat-absorbing plate 300 and the metal casing 100. The heat-absorbing plate 300, which absorbs heat from the metal casing 100, preheats the water inlet pipe 110 through the water inlet preheating part 310. This allows the cold water in the water inlet pipe 110 to absorb a certain amount of heat before entering the heating component, thereby reducing the power consumption of the heating component and achieving high thermal efficiency.

[0025] Furthermore, to ensure heat conduction between the metal casing 100 and the heat absorber plate 300, thermally conductive silicone can be provided between the main body 320 and the bottom 150 of the metal casing, and / or thermally conductive silicone can be provided between the extension portion 330 and the side portion 160 of the metal casing, so as to achieve good heat conduction between the heat absorber plate 300 and the metal casing 100.

[0026] In a preferred embodiment of this invention, the water inlet preheating section 310 can be arc-shaped, with its inner wall fitting against the outer wall of the water inlet pipe 110. Alternatively, the water inlet preheating section 310 can be cylindrical, fitted onto the outside of the water inlet pipe 110, with its inner wall fitting against the outer wall of the water inlet pipe 110. Using these methods, the water inlet pipe 110 can absorb heat to the maximum extent, achieving the preheating function. In the prior art, fins and similar shapes are commonly used as preheating devices to achieve good heat exchange. However, while using fins for heat exchange promotes the flow of the heat exchange medium and results in high heat exchange efficiency, the heat exchange rate is slow, failing to rapidly reduce the temperature of the metal casing 100 and thus not meeting the heat dissipation requirements of the heating component. Furthermore, since the water only flows within the water inlet pipe 110, it cannot be properly integrated with the fin shape, leading to low heat exchange efficiency. Therefore, the preheating function adopts the above two forms, which fully takes into account the needs of preheating water and rapidly dissipating heat from the heating components.

[0027] The heating assembly also includes a heat absorber plate 300, which is assembled and connected to the metal casing 100. Both the metal casing 100 and the water inlet pipe 110 are thermally connected to the heat absorber plate 300. The assembly and connection methods between the heat absorber plate 300 and the metal casing 100 include, but are not limited to, screw connections, welding, and bonding. Preferably, the heat absorber plate 300 and the metal casing 100 are connected in a detachable manner; for example, the heat absorber plate 300 and the metal casing 100 are connected by screws.

[0028] Using the above method, the heat absorber plate 300 can be tightly fitted to the metal casing 100 and is not easily detached. Furthermore, depending on the actual situation, the bottom 150 of the metal casing can be at least partially thermally connected to the main body 320, and / or the side 160 of the metal casing can be at least partially thermally connected to the extension 330. It should be noted that the bottom 150 of the metal casing refers to the ends along the length of the metal casing 100, while the side 160 refers to the portion along the length of the metal casing 100 excluding the ends. This reduces the difficulty of assembly and processing while still meeting the requirement of absorbing heat from the metal casing 100. Optionally, the heat absorber plate 300 can be made of aluminum, which is a highly efficient heat conductor; heat is mainly transferred through the thermal motion of free electrons, making it suitable for rapid heat dissipation scenarios. Especially in the case of partial contact, using an aluminum heat absorber plate 300 can not only quickly absorb heat from the metal casing 100 but also assist the metal casing 100 in rapid heat dissipation.

[0029] In a preferred embodiment of this example, the metal casing 100 is equipped with a thermostat 400. The thermostat 400 includes a bimetallic temperature sensor 410 and a cover 420. The bimetallic temperature sensor 410 is installed inside the cover 420, and a convection space 500 is formed between the bimetallic temperature sensor 410 and the inner wall of the cover 420. As an example, the thermostat 400 is a high-sensitivity, long-life snap-action thermostat 400. See also... Figure 4 The bimetallic temperature sensor 410 is precisely riveted to the inside of the metal cover 420 of the thermostat 400, with an annular convection space 500 reserved between it and the inner wall of the cover 420. The presence of this convection space 500 allows the transient temperature difference generated inside the metal casing 100 due to the starting and stopping of the heating tube 200 to be rapidly transferred to the surface of the bimetallic temperature sensor 410 via convection. This convection space 500 design ensures that both the inner and outer surfaces of the bimetallic temperature sensor 410 can contact the heat source, enabling the surface temperature of the bimetallic temperature sensor 410 to quickly reach the set temperature, closely matching the actual heating temperature. This allows for timely disconnection of the heating power, preventing dry burning and effectively improving the sensitivity and reliability of the thermostat 400.

[0030] Optionally, the overall structure of the bimetallic temperature sensor 410 is triangular, square, rectangular, trapezoidal, rhomboid, pentagonal, hexagonal, elliptical, or fan-shaped, and / or the convection space 500 between the bimetallic temperature sensor 410 and the cover 420 is triangular, square, rectangular, trapezoidal, rhomboid, pentagonal, hexagonal, elliptical, or fan-shaped. In the above examples, various shapes are chosen to facilitate the processing of the bimetallic temperature sensor 410. Those skilled in the art can process the structure of the bimetallic temperature sensor as needed to form the aforementioned convection space 500, allowing air convection on both sides of the bimetallic temperature sensor 410. This enables the bimetallic temperature sensor 410 to accurately detect the actual heating temperature and promptly cut off the heating power.

[0031] In a preferred embodiment of this invention, the metal casing 100 has at least two heating tubes 200 inside. The metal casing 100 has a mounting side, on which a thermostat 400 is mounted. The projection of the thermostat 400 onto the mounting side of the metal casing 100 is located between two of the heating tubes 200. This structural design results in a compact layout of the heating components, high space utilization, and enables three-dimensional, surround heating of the water flow, effectively improving heating efficiency and heat exchange uniformity, and avoiding problems such as localized overheating or heating dead zones.

[0032] The cold water flowing into the inlet pipe 110 can be heated simultaneously or individually using one or more of at least two heating elements 200, depending on the set temperature and flow rate of the outlet pipe 120. For example, the number of heating elements 200 that can be activated can be flexibly selected based on parameters such as the set outlet temperature, inlet temperature, and flow rate to achieve multi-level power adjustment and meet the hot water needs of different usage scenarios.

[0033] For example, when the inlet water temperature is high or the required outlet water temperature is low, and the water flow rate is low, only one heating element 200 can be used to achieve energy-saving operation. When the inlet water temperature is low, the required outlet water temperature is high, or the water flow rate is high, multiple heating elements 200 can be activated simultaneously to quickly raise the water temperature and ensure stable heating. Using this method not only improves energy efficiency and reduces unnecessary energy consumption, but also effectively extends the service life of the heating elements 200, avoiding the accelerated aging problem caused by long-term full-load operation.

[0034] In addition, the independent control design of each heating element 200 also has a fault redundancy function. When one heating element 200 fails, it can be automatically or manually switched to the remaining normal heating elements 200 to continue working, ensuring the basic heating capacity of the equipment and improving the reliability and stability of the system.

[0035] See Figure 5Furthermore, at least two of the heating tubes 200 have different heating powers. For example, in a scheme with three heating tubes, the three heating tubes 200 can be configured with high power, medium power, and low power, respectively. The specific power values ​​can be matched and designed according to the product's rated total power, target temperature rise, and maximum flow rate. Through differentiated power configuration, the system can achieve a more refined heating gradient and a wider range of load adjustment capabilities without increasing additional hardware costs.

[0036] When operating with a single tube, users can prioritize using the low-power heating tube 200 for "heat preservation" or "low flow" heating, which can meet minor hot water needs while avoiding current surges caused by high-power start-up and shutdown. When using a dual-tube combination, users can choose between "low + medium" or "low + high" combinations to achieve medium-speed heating. When all three tubes are fully activated, the high, medium, and low power levels are superimposed to quickly output a large flow of high-temperature hot water, meeting the needs of extreme conditions such as low-temperature water intake in winter or continuous water use by multiple users.

[0037] Furthermore, using the above setup, different combinations of heating tubes 200 can be flexibly activated at different stages to optimize the preheating effect. For example, initially, all three tubes can be activated simultaneously, with the heat absorption plate 300 absorbing a large amount of heat from the metal casing 100 to preheat the water flowing into the inlet pipe 110. When the temperature of the preheated water is not significantly different from the target water temperature, one of the heating tubes 200 can be appropriately shut off to fully utilize the preheating effect, reduce power consumption, and lower the internal temperature of the heating element.

[0038] For example, heating can be achieved in three ways: one heating element 200 has a heating power of 800 watts, and the other two heating elements 200 have a heating power of 600 watts. The achievable operating modes include: 1. Controlling one 600-watt heating element 200 with the thermostat 400 to achieve a 600-watt heating power mode. 2. Controlling both 600-watt heating elements 200 with the thermostat 400 to achieve a 1200-watt heating power mode. 3. Controlling both the 800-watt and 600-watt heating elements 200 with the thermostat 400 to achieve a 2000-watt heating power mode.

[0039] Correspondingly, the metal casing 100 is also provided with a water outlet pipe 120. The water outlet pipe 120 and the water inlet pipe 110 can be respectively arranged at both ends of the length direction of the metal casing 100, forming a symmetrical arrangement structure. This helps to achieve a balanced distribution of water flow, improve heat exchange efficiency, and also provides more ample installation and operating space for the internal heating components and water system, avoiding problems such as compact structure and poor heat dissipation caused by centralized pipe arrangement. It should be noted that the length direction of the metal casing 100 is... Figure 2 The middle arrow indicates direction.

[0040] The metal casing 100 has a water inlet end seat and a water outlet end seat. The water inlet end seat is provided with a water inlet and at least two water outlets. The water inlet is connected to the water inlet pipe 110. Each of the heating tubes 200 can be designed as a parallel structure or a series structure according to actual usage requirements.

[0041] When the heating tubes 200 are arranged in parallel, each heating tube 200 is arranged in a one-to-one correspondence with the water inlet, and each water inlet is connected to the inlet end of the corresponding heating tube 200. The outlet end seat is provided with one drain outlet and at least two outlets, each outlet is arranged in a one-to-one correspondence with the heating tube 200, and each outlet is connected to the outlet end of the corresponding heating tube 200. The drain outlet is connected to the outlet pipe 120. The parallel arrangement is beneficial for increasing water flow and is suitable for applications with high flow requirements.

[0042] When the heating tubes 200 are arranged in series, there are at least two heating tubes 200 connected end to end. The inlet pipe 110 is connected to the first heating tube 200 connected end to end, and the outlet pipe 120 is connected to the last heating tube 200 connected end to end. Alternatively, each heating tube 200 may consist of a single water pipe, which is spirally coiled inside the metal casing. The inlet end of the water pipe is connected to the inlet pipe 110, and the outlet end of the water pipe is connected to the outlet pipe 120. This series arrangement helps to extend the water flow path, improve heating uniformity and thermal efficiency, and is suitable for applications requiring high heating temperatures.

[0043] In terms of structural connection, the inlet pipe 110 and the outlet pipe 120 can be integrally formed with the metal casing 100. This integrated design not only simplifies the manufacturing process and reduces the number of parts, effectively reducing assembly difficulty and production costs, but also enhances the overall structural sealing and mechanical strength, improving product reliability and service life.

[0044] Optionally, the inlet pipe 110 and outlet pipe 120 can also adopt a detachable assembly structure, such as being connected to the metal casing 100 by threaded connection, flange connection, or snap-fit ​​connection. The assembly structure design facilitates later maintenance, repair, and component replacement, improving the maintainability and flexibility of the product, and is especially suitable for applications requiring frequent maintenance or a high degree of customization.

[0045] In a preferred embodiment of this invention, the metal outer shell 100 includes an upper lobe shell 130 and a lower lobe shell 140, which are fixed together by a snap-fit ​​structure 170. For example, the metal outer shell 100 adopts a split "double-lobed" structure, consisting of an upper lobe shell 130 and a lower lobe shell 140, with a male-female snap-fit ​​structure 170 pre-formed at their mating surfaces.

[0046] The aforementioned split-type quick-release design facilitates production and installation. The entire machine is manufactured at the end of the production line using a fully automated pressing method. During later maintenance, maintenance personnel only need simple tools to quickly open the metal outer shell 100, replace and repair the internal components, and then re-press it to restore the original locking force, ensuring that its strength still meets the design requirements.

[0047] Furthermore, due to the adoption of a structure with a heat-absorbing plate 300, the temperature of the metal shell 100 can always be kept within a reasonable temperature range during the use of the heating component, without deformation. This avoids the technical problems of disassembly difficulties and maintenance assembly difficulties caused by thermal deformation, and can also effectively extend the overall service life of the heating component.

[0048] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A heating assembly comprising a metal housing (100) and a heating element (200), the heating element (200) being at least partially located within the metal housing (100), the metal housing (100) having a water inlet pipe (110); characterized in that: It also includes a heat absorption plate (300), which is assembled and connected to the metal shell (100). The metal shell (100) and the water inlet pipe (110) are simultaneously thermally connected to the heat absorption plate (300).

2. A heating assembly according to claim 1, characterized in that: A portion of the heat absorber plate (300) is arranged corresponding to the metal shell (100), and the portion of the heat absorber plate (300) arranged corresponding to the metal shell (100) is thermally connected to the metal shell (100). Another portion of the heat absorber plate (300) is arranged corresponding to the water inlet pipe (110), and the portion of the heat absorber plate (300) arranged corresponding to the water inlet pipe (110) is thermally connected to the water inlet pipe (110).

3. A heating assembly according to claim 1 or 2, characterized in that: The heat absorber plate (300) includes an extension portion (330), a main body portion (320), and a water inlet preheating portion (310). The water inlet preheating portion (310) is located at the end of the main body portion (320) away from the extension portion (330). The portion of the heat absorber plate (300) that is thermally connected to the metal shell (100) is located in the extension portion (330), and the portion of the heat absorber plate (300) that is thermally connected to the water inlet pipe (110) is located in the water inlet preheating portion (310).

4. A heating assembly according to claim 3, characterized in that: The bottom (150) of the metal casing is at least partially thermally connected to the main body (320), and / or the side (160) of the metal casing is at least partially thermally connected to the extension (330).

5. A heating assembly according to claim 3, characterized in that: Thermally conductive silicone is provided between the main body (320) and the bottom (150) of the metal casing, and / or thermally conductive silicone is provided between the extension (330) and the side (160) of the metal casing.

6. A heating assembly according to claim 4 or 5, characterized in that: The water inlet preheating section (310) is arc-shaped, and the inner wall of the arc-shaped water inlet preheating section (310) is in contact with the outer wall of the water inlet pipe (110). Alternatively, the water inlet preheating section (310) is cylindrical, and the cylindrical water inlet preheating section (310) is fitted on the outside of the water inlet pipe (110), and the inner wall of the cylindrical water inlet preheating section (310) is in contact with the outer wall of the water inlet pipe (110).

7. A heating assembly according to claim 1, characterized in that: The metal casing (100) has at least two heating tubes (200) inside. The metal casing (100) has a mounting side, and a thermostat (400) is mounted on the mounting side. The projection of the thermostat (400) in the direction facing the mounting side of the metal casing (100) is located between two of the heating tubes (200). The heating power of the at least two heating tubes (200) is different. And / or, the heat absorber plate (300) is made of aluminum; And / or, the metal housing (100) includes an upper lobe housing (130) and a lower lobe housing (140), the upper lobe housing (130) and the lower lobe housing (140) being fixed by a snap-fit ​​structure (170).

8. A heating assembly according to claim 1, 2, 4, or 5, characterized in that: The metal casing (100) is equipped with a thermostat (400), which includes a bimetallic temperature sensor (410) and a cover (420). The bimetallic temperature sensor (410) is installed inside the cover (420), and there is a convection space (500) between the bimetallic temperature sensor (410) and the inner wall of the cover (420).

9. A heating assembly according to claim 8, characterized in that: The overall structure of the bimetallic thermal sensor (410) is triangular, square, rectangular, trapezoidal, rhomboid, pentagonal, hexagonal, elliptical, or fan-shaped, and / or the convection space (500) between the bimetallic thermal sensor (410) and the cover (420) is triangular, square, rectangular, trapezoidal, rhomboid, pentagonal, hexagonal, elliptical, or fan-shaped.

10. A heating assembly according to claim 1, 2, 4, 5, 7, or 9, characterized in that: The metal casing (100) is also provided with a water outlet pipe (120), and the water outlet pipe (120) and the water inlet pipe (110) are respectively arranged at both ends of the length direction of the metal casing (100); The metal casing (100) has an inlet end seat and an outlet end seat. The inlet end seat has one inlet and at least two outlets. The inlet is connected to the inlet pipe (110). The heating pipes (200) are arranged one-to-one with the outlets, and the outlets are connected to the inlet ends of the corresponding heating pipes (200). The outlet end seat has one drain outlet and at least two outlets. The outlets are arranged one-to-one with the heating pipes (200), and the outlets are connected to the outlet ends of the corresponding heating pipes (200). The drain outlet is connected to the outlet pipe (120). Alternatively, The number of heating tubes (200) is at least two, and the at least two heating tubes (200) are connected end to end. The water inlet pipe (110) is connected to the first heating tube (200) connected end to end, and the water outlet pipe (120) is connected to the last heating tube (200) connected end to end. Alternatively, the heating tube (200) includes a whole water pipe, and the whole water pipe is spirally coiled inside the metal shell. The water inlet end of the water pipe is connected to the water inlet pipe (110), and the water outlet end of the water pipe is connected to the water outlet pipe (120).

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