An electric heating device for heating a liquid using a tube

Abstract

This invention discloses an electric heating device for heating liquids using pipes, comprising a sheet-shaped heating assembly and a liquid guiding pipe. The sheet-shaped heating assembly heats the liquid guiding pipe. N groups of liquid guiding pipes are arranged parallel to each other to form a liquid guiding pipe group. A heating space is formed between any two adjacent liquid guiding pipes. A set of sheet-shaped heating assemblies is located on the side of the heating space and / or the liquid guiding pipe group, parallel to the liquid guiding pipe, forming a heated liquid guiding group. The device also includes a first clamping plate, a second clamping plate, and a clamping member. The first clamping plate is located on a first side of the heated liquid guiding group, and the second clamping plate is located on a second side of the heated liquid guiding group, with the first and second sides opposite each other. The clamping member is located between the first and second clamping plates and is used to adjust the distance between the first and second clamping plates. This invention has a simple structure and does not require additional wedge-shaped components or other structures to fix the sheet-shaped heating assembly, thus facilitating installation and disassembly.

Description

Technical Field

[0001] This invention relates to the field of circulating liquid heating technology, and more particularly to an electric heating device that uses a pipeline to heat liquid. Background Technology

[0002] The power battery is the core component of an electric vehicle, but it is quite sensitive to temperature; low temperatures can affect its discharge performance. To ensure better discharge and extend its lifespan, the power battery needs to be heated during electric vehicle operation in low-temperature conditions.

[0003] Currently, the main methods for heating power batteries include hot air heating, liquid heating, and PCT heating. Liquid heating involves heating the liquid externally or inside the battery pack, allowing it to flow around the battery and thus heat it. The liquid heating equipment for the power battery delivers the liquid through vehicle piping to the heating element of the air conditioning unit in the passenger compartment. This heated air meets the heating needs of the passenger compartment, thereby achieving heating. However, liquid heating often requires a heating device to heat the circulating liquid. Typically, this involves heating wires or heating plates to heat the water pipes, thus heating the circulating liquid. Existing plate-shaped heating components are fixed to the water pipes using pins or wedges, which is inconvenient for installation and assembly.

[0004] Therefore, an electric heating device for heating liquids using pipes is proposed, which is easy to install and assemble with sheet heating components and has relatively high heating efficiency. Summary of the Invention

[0005] To address the technical problems existing in the background art, the present invention proposes an electric heating device for heating liquids using a pipeline.

[0006] This invention proposes an electric heating device for heating liquids using pipes, comprising a sheet-shaped heating assembly and a liquid guiding pipe. The sheet-shaped heating assembly heats the liquid guiding pipe. The liquid guiding pipe is provided in N groups, where N is an integer greater than or equal to 2. The N groups of liquid guiding pipes are arranged parallel to each other to form a liquid guiding pipe group. A heating space is formed between any two adjacent liquid guiding pipes. A set of sheet-shaped heating assemblies is provided on the side of the heating space and / or the liquid guiding pipe group. The sheet-shaped heating assembly and the liquid guiding pipe are parallel to each other, and the sheet-shaped heating assembly and the liquid guiding pipe form a heated liquid guiding group.

[0007] It also includes a first clamping plate, a second clamping plate, and a clamping member. The first clamping plate is disposed on the first side of the heating liquid guiding assembly, and the second clamping plate is disposed on the second side of the heating liquid guiding assembly. The first side and the second side are opposite to each other. The clamping member is disposed between the first clamping plate and the second clamping plate and is used to adjust the distance between the first clamping plate and the second clamping plate.

[0008] Furthermore, the liquid guide tube is made of a deformable metal material, preferably an aluminum alloy.

[0009] Furthermore, it also includes a collecting pipe, which is provided in two sets. One set of the collecting pipe is fixed and connected to the inlet end of the liquid guiding pipe, and the other set of the collecting pipe is fixed and connected to the outlet end of the liquid guiding pipe.

[0010] Preferably, the collecting pipe and the liquid guiding pipe are fixed by welding.

[0011] Preferably, the system further includes a water tank, in which the plate-shaped heating assembly, the liquid guide pipe, and the collecting pipe are installed. The system also includes an inlet pipe and an outlet pipe. The inlet pipe is fixed to the collecting pipe connected to the inlet end of the liquid guide pipe and communicates with the collecting pipe. The outlet pipe is fixed to the collecting pipe connected to the outlet end of the liquid guide pipe and communicates with the collecting pipe. The inlet pipe and the outlet pipe extend out of the water tank.

[0012] Preferably, the inlet pipe and the outlet pipe are fixed to the collecting pipe by welding.

[0013] Preferably, the liquid guide tube is U-shaped and bent inside the water tank.

[0014] Preferably, the device further includes a controller, a first temperature sensor, and a second temperature sensor. The first temperature sensor is used to detect the liquid temperature at the inlet end of the liquid guide tube, and the second temperature sensor is used to detect the liquid temperature at the outlet end of the liquid guide tube. The temperatures detected by the first and second temperature sensors are transmitted to the controller. The controller is also connected to the sheet heating assembly. The controller controls the heating power of the sheet heating assembly based on the temperatures detected by the first temperature sensor and the second temperature sensor.

[0015] Preferably, the sheet-shaped heating assembly and the liquid guide tube are in surface contact.

[0016] The liquid guide tube can be a harmonica tube or a single-port tube as in the prior art. In order to further increase the heating efficiency, preferably, the liquid guide tube has an alternating connecting channel and a heat-conducting channel. Both the connecting channel and the heat-conducting channel are opposite to the plate heating component. The connecting channel is connected to the liquid inlet and liquid outlet of the liquid guide tube, and the two ends of the heat-conducting channel are closed.

[0017] Preferably, a heat-conducting element is provided between any adjacent connecting channel and heat-conducting channel, the heat-conducting element having a portion extending into the connecting channel and a portion extending into the connecting channel.

[0018] In some preferred embodiments, the heat-conducting element is rotatably mounted on the liquid-conducting pipe, and the axis of rotation of the heat-conducting element is perpendicular to the flow velocity of the liquid flowing in the flow channel. In order to further increase the heating efficiency, the outer surface of the heat-conducting element is provided with a stirring fan blade. In this embodiment, there is no liquid flow in the heat-conducting channel.

[0019] In some preferred embodiments, the heat-conducting element is rotatably mounted on the liquid guide tube, and the axis of rotation of the heat-conducting element is perpendicular to the flow velocity of the liquid flowing in the flow channel.

[0020] In some preferred embodiments, the heat-conducting element is cylindrical, with its axial direction parallel to the liquid flow velocity within the flow channel. A partition plate is provided between the flow channel and the heat-conducting channel. The heat-conducting element has a portion located in the flow channel and a portion located in the heat-conducting channel. During operation, the heat-conducting element can rotate relative to the liquid guide tube to further increase the heating effect. Preferably, a spiral liquid guide groove can be opened on the outer side of the heat-conducting element.

[0021] The proposed electric heating device for heating liquids via pipes increases heating efficiency by incorporating a sheet-like heating element between the liquid guide pipes. The first and second clamping plates facilitate the fixing of the sheet-like heating element and the liquid guide pipes, eliminating the need for additional wedge-shaped components or other structures, thus simplifying installation and disassembly. Furthermore, the liquid guide pipes are fixed to the manifold by welding, ensuring a tight seal compared to conventional methods using rubber seals. Additionally, the liquid guide pipes are made of aluminum alloy, reducing overall weight. Moreover, the heating efficiency is further increased by incorporating flow channels and heat conduction channels.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the internal structure of the water tank of the present invention;

[0025] Figure 3 This is a partial cross-sectional view of the present invention;

[0026] Figure 4 This is a schematic diagram of the exploded structure of the present invention;

[0027] Figure 5 This is a schematic diagram of the internal structure of the liquid guide tube in some embodiments of the present invention;

[0028] Figure 6This is a schematic diagram of the internal structure of the liquid guide tube in some embodiments of the present invention;

[0029] Figure 7 This is a schematic diagram of the heat-conducting component structure in some embodiments of the present invention;

[0030] In the figure: 1. Sheet-shaped heating assembly; 10. First ceramic substrate; 11. First electrode sheet; 12. Ceramic heating sheet; 13. Limiting frame; 14. Second electrode sheet; 15. Second ceramic substrate; 2. Liquid guide tube; 20. Connecting channel; 21. Heat conduction channel; 3. First clamping plate; 4. Second clamping plate; 5. Clamping component; 6. Insulating film; 7. Manifold; 8. Water tank; 80. Upper shell of water tank; 81. Lower shell of water tank; 9. Controller; 16. First temperature detection component; 17. Second temperature detection component; 18. Heat conduction component; 180. Liquid guide groove; 19. Liquid inlet pipe; 22. Liquid outlet pipe. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] like Figures 1-4 An electric heating device for heating liquid using a pipe is shown, comprising a sheet heating component 1 and a liquid guiding pipe 2. The sheet heating component 1 heats the liquid guiding pipe 2. The liquid guiding pipe 2 is provided in N groups, where N is an integer greater than or equal to 2. The N groups of liquid guiding pipe 2 are arranged parallel to each other to form a liquid guiding pipe group. A heating space is formed between any two adjacent liquid guiding pipes 2. A set of sheet heating components 1 is provided on the side of the heating space and / or the liquid guiding pipe group. The sheet heating component 1 and the liquid guiding pipe 2 are parallel, and the sheet heating component 1 and the liquid guiding pipe 2 form a heating liquid guiding group.

[0033] It also includes a first clamping plate 3, a second clamping plate 4, and a clamping member 5. The first clamping plate 3 and the second clamping plate 4 are parallel to the sheet heating assembly 1. The first clamping plate 3 is disposed on the first side of the heating liquid guiding group, and the second clamping plate 4 is disposed on the second side of the heating liquid guiding group. The first side and the second side are opposite to each other. The clamping member 5 is disposed between the first clamping plate 3 and the second clamping plate 4 and is used to adjust the distance between the first clamping plate 3 and the second clamping plate 4.

[0034] Specifically, the sheet heating assembly 1 can be the sheet heating assembly 1 in the prior art. In this embodiment, the sheet heating assembly 1 includes a first ceramic substrate 10, a first electrode sheet 11, a ceramic heating sheet 12, a limiting frame 13, a second electrode sheet 14, and a second ceramic substrate 15. The first electrode sheet 11 and the second electrode sheet 14 are parallel to each other and opposite to each other. The ceramic heating sheet 12 is disposed between the first electrode sheet 11 and the second electrode sheet 14 to form a heating group. The limiting frame 13 is fixed on the outside of the heating group and fixes the relative positions of the first electrode sheet 11, the second electrode sheet 14, and the ceramic heating sheet 12. The first ceramic substrate 10 and the second ceramic substrate 15 are opposite to each other and parallel to each other. The heating group is disposed between the first ceramic substrate 10 and the second ceramic substrate 15.

[0035] It should be noted that the first ceramic substrate 10 and the second ceramic substrate 15 of the sheet heating assembly 1 located in the heating space are in contact (or rather, in close contact) with the side of the liquid guide tube 2.

[0036] The first ceramic substrate 10 of the sheet heating assembly 1 located outside the liquid guide tube assembly abuts against the side of the liquid guide tube 2, and the second ceramic substrate 15 abuts against the first clamping plate 3 or the second clamping plate 4. Preferably, an insulating film 6 is provided between the first clamping plate 3 and the second ceramic substrate 15, and an insulating film 6 is also provided between the second clamping plate 4 and the second ceramic substrate 15.

[0037] During installation, the sheet heating assembly 1 is first assembled, then placed in the heating space, followed by placing sheet heating assemblies 1 on both sides of the liquid guiding tube assembly. The first clamping plate 3 is then pressed against one set of outer sheet heating assemblies 1, and the second clamping plate 4 is pressed against another set of outer sheet heating assemblies 1. The first clamping plate 3 and the second clamping plate 4 are then fixed using clamping elements 5. Specifically, the clamping element 5 is a bolt, including a stud and a nut. The stud passes through the first clamping plate 3 and the second clamping plate 4, and the nut is threaded to the stud. Rotating the nut allows the first clamping plate 3 and the second clamping plate 4 to be fixed together. The second clamping plate 4 fixes the sheet heating assembly 1 and the liquid guiding tube assembly, thereby completing the installation and fixation of the sheet heating assembly 1. During this process, the liquid guiding tube 2 is a harmonica tube made of aluminum alloy, which is lightweight, has good thermal conductivity, and can undergo partial deformation to facilitate the heating of the liquid guiding tube 2 by the sheet heating assembly 1. By setting the sheet heating assembly 1 between the liquid guiding tubes 2, the heating efficiency is increased. The setting of the first clamping plate 3 and the second clamping plate 4 facilitates the fixation of the sheet heating assembly 1 and the liquid guiding tube 2 without the need for additional wedge-shaped parts or other structures to fix the sheet heating assembly 1, thus facilitating installation and disassembly.

[0038] Preferably, it also includes a manifold 7, which has two sets. One set of manifold 7 is fixed and connected to the inlet end of the liquid guide tube 2, and the other set of manifold 7 is fixed and connected to the outlet end of the liquid guide tube 2. Preferably, the manifold 7 and the liquid guide tube 2 are fixed by welding. The manifold 7 is made of metal material. Compared with the existing sealing by rubber rings and other sealing methods, the sealing and fixing by welding achieves the sealing of the two components at the same time as fixing the two components.

[0039] Preferably, it also includes a water tank 8, a plate heating assembly 1, a liquid guide pipe 2 and a collecting pipe 7 installed in the water tank 8, and an inlet pipe 19 and an outlet pipe 22. The inlet pipe 19 is fixed to the collecting pipe 7 connected to the inlet end of the liquid guide pipe 2 and communicates with the collecting pipe 7. The outlet pipe 22 is fixed to the collecting pipe 7 connected to the outlet end of the liquid guide pipe 2 and communicates with the collecting pipe 7. The inlet pipe 19 and the outlet pipe 22 extend out of the water tank 8 and are connected to external pipes.

[0040] Specifically, the water tank 8 includes an upper shell 80 and a lower shell 81. The upper shell 80 and the lower shell 81 are detachably connected and form a cavity between them. The plate heating assembly 1, the liquid guide pipe 2, and the collecting pipe 7 are installed in the cavity. The liquid inlet pipe 19 and the liquid outlet pipe 22 are fixed on the lower shell 81.

[0041] Preferably, the inlet pipe 19 and the outlet pipe 22 are fixed to the manifold 7 by welding, thereby sealing the two components while ensuring their fixation.

[0042] Preferably, the liquid guide tube 2 is bent in a U-shape inside the water tank 8 to further increase the heating efficiency, as shown in the figure, the plate heating component 1 is provided with two sets.

[0043] Preferably, the system further includes a controller 9, a first temperature sensor 16, and a second temperature sensor 17. The first temperature sensor 16 is used to detect the liquid temperature at the inlet end of the liquid guide tube 2, and the second temperature sensor 17 is used to detect the liquid temperature at the outlet end of the liquid guide tube 2. The temperatures detected by the first temperature sensor 16 and the second temperature sensor 17 are transmitted to the controller 9. The controller 9 is also connected to the sheet heating assembly 1. The controller 9 controls the heating power of the sheet heating assembly 1 according to the temperatures detected by the first temperature sensor 16 and the second temperature sensor 17. The controller 9 is installed on the water tank 8, and the first temperature sensor 16 is installed on the manifold 7 connected to the inlet end of the liquid guide tube 2 to detect the temperature of the liquid in the manifold 7. The second temperature sensor 17 is installed on the manifold 7 connected to the outlet end of the liquid guide tube 2 to detect the temperature of the liquid in the manifold 7. Specifically, the first temperature sensor 16 and the second temperature sensor 17 can be temperature sensors.

[0044] During the heating process of the sheet heating component 1 controlled by the controller 9, the heating power of the controller 9 is first determined according to the required temperature of the liquid at the outlet of the liquid guide tube 2. Since the initial temperature of the battery module is low, the temperature detected by the first temperature detection element 16 is relatively low, so the power of the sheet heating component 1 is relatively high. In addition, as the heating time of the power battery module increases, the temperature of the battery module increases, and the temperature detected by the first temperature detection element 16 will also increase. Therefore, the power of the sheet heating component 1 can be reduced to ensure the liquid temperature at the outlet of the second temperature detection element 17.

[0045] Preferably, the sheet-shaped heating component 1 and the liquid guide tube 2 are in surface contact, which further increases the heating efficiency.

[0046] To further increase heating efficiency, preferably, the liquid guide tube 2 has an alternating connecting channel 20 and a heat conduction channel 21, both of which are opposite to the sheet heating component 1. The connecting channel 20 is connected to the liquid inlet and the liquid outlet of the liquid guide tube 2, that is, both ends of the connecting channel 20 are connected to the collecting pipe 7, while both ends of the heat conduction channel 21 are not connected to the collecting pipe 7 and are closed.

[0047] To further increase heating efficiency, preferably, a heat-conducting element 18 is provided between any adjacent connecting channel 20 and heat-conducting channel 21, the heat-conducting element 18 having a portion extending to the connecting channel 20 and also having a portion extending to the connecting channel 20.

[0048] like Figure 4 As shown, in some embodiments, preferably, the heat-conducting element 18 is rotatably mounted on the liquid guide tube 2, and the axis of rotation of the heat-conducting element 18 is perpendicular to the flow velocity of the liquid flowing in the flow channel. In order to further increase the heating efficiency, the outer surface of the heat-conducting element 18 is provided with a stirring fan blade. In this embodiment, there is no liquid flow in the heat-conducting channel 21.

[0049] Preferably, the heat-conducting element 18 is rotatably mounted on the bellows tube, and the axis of rotation of the heat-conducting element 18 is perpendicular to the flow velocity of the liquid flowing in the flow channel. On the one hand, the heat-conducting element 18 turbulents the liquid flowing through the flow channel, and on the other hand, it increases the heat exchange efficiency.

[0050] like Figure 5 In some preferred embodiments, the heat-conducting element 18 is cylindrical, and the axial direction of the heat-conducting element 18 is parallel to the liquid flow velocity in the flow channel. There is a partition plate between the flow channel and the heat-conducting channel 21. The heat-conducting element 18 has a portion located in the flow channel and a portion located in the heat-conducting channel 21. During operation, the heat-conducting element 18 can rotate relative to the liquid guide tube 2 to further increase the heating effect.

[0051] like Figure 6 , Figure 7As shown, preferably, a spiral liquid guiding groove 180 can be opened on the outer side of the heat-conducting component 18. The liquid guiding groove 180 can transfer the liquid in the flow channel to the heat-conducting channel 21. The flow efficiency of the liquid in the heat-conducting channel 21 is lower than the flow velocity of the liquid in the flow channel, and the temperature of the liquid in the heat-conducting channel 21 is higher than the temperature of the liquid in the flow channel. During the rotation of the heat-conducting component 18, the spiral liquid guiding groove 180 transfers the liquid in area A of the heat-conducting channel 21 to area B of the flow channel. Specifically, area B is closer to the liquid inlet end of the flow channel than area A, thereby increasing the heating efficiency.

[0052] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention 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. Therefore, they should not be construed as limitations on the present invention.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An electric heating device for heating liquid using a pipe, comprising a sheet heating assembly (1) and a liquid guiding pipe (2), wherein the sheet heating assembly (1) heats the liquid guiding pipe (2), characterized in that, The liquid guiding tube (2) is provided in N groups, where N is an integer greater than or equal to 2. The N groups of liquid guiding tubes (2) are arranged in parallel to each other to form a liquid guiding tube group. A heating space is formed between any two adjacent liquid guiding tubes (2). A set of sheet heating components (1) is provided on the side of the heating space and / or the liquid guiding tube group. The sheet heating components (1) are parallel to the liquid guiding tubes (2). The sheet heating components (1) and the liquid guiding tubes (2) form a heating liquid guiding group. It also includes a first clamping plate (3), a second clamping plate (4), and a clamping member (5). The first clamping plate (3) is disposed on the first side of the heating liquid guiding group, and the second clamping plate (4) is disposed on the second side of the heating liquid guiding group. The first side and the second side are opposite to each other. The clamping member (5) is disposed between the first clamping plate (3) and the second clamping plate (4) and is used to adjust the distance between the first clamping plate (3) and the second clamping plate (4). It also includes a collection pipe (7), which is provided in two sets. One set of the collection pipe (7) is fixed and connected to the inlet end of the liquid guide pipe (2), and the other set of the collection pipe (7) is fixed and connected to the outlet end of the liquid guide pipe (2). The liquid guide tube (2) has an alternating connecting channel (20) and a heat conduction channel (21). Both the connecting channel (20) and the heat conduction channel (21) are opposite to the sheet heating component (1). The connecting channel (20) is connected to the liquid inlet and the liquid outlet of the liquid guide tube (2). That is, the two ends of the connecting channel (20) are connected to the collecting pipe (7). The two ends of the heat conduction channel (21) are not connected to the collecting pipe (7). The two ends of the heat conduction channel (21) are closed. A heat-conducting element (18) is provided between any adjacent connecting channel (20) and heat-conducting channel (21). The heat-conducting element (18) has a portion extending to the connecting channel (20) and a portion extending to the heat-conducting channel (21). The heat-conducting element (18) is rotatably mounted on the liquid guide tube (2), and the axis of rotation of the heat-conducting element (18) is perpendicular to the flow velocity of the liquid flowing in the flow channel. The outer side of the heat-conducting element (18) has a spiral liquid guide groove (180).

2. The electric heating device for heating a liquid using a pipe according to claim 1, characterized by, The liquid guide tube (2) is made of a deformable metal material.

3. The electric heating device for heating liquid using a pipeline according to claim 1, characterized in that, The collecting pipe (7) and the liquid guiding pipe (2) are fixed by welding.

4. The electric heating device for heating liquid using a pipeline according to claim 1, characterized in that, It also includes a water tank (8), the plate heating assembly (1), the liquid guide pipe (2) and the collecting pipe (7) are installed in the water tank (8), and also includes an inlet pipe (19) and an outlet pipe (22). The inlet pipe (19) is fixed to the collecting pipe (7) connected to the inlet end of the liquid guide pipe (2) and communicates with the collecting pipe (7). The outlet pipe (22) is fixed to the collecting pipe (7) connected to the outlet end of the liquid guide pipe (2) and communicates with the collecting pipe (7). The inlet pipe (19) and the outlet pipe (22) extend out of the water tank (8).

5. The electric heating device for heating a liquid with a pipe according to claim 4, characterized in that, The inlet pipe (19) and the outlet pipe (22) are fixed to the collecting pipe (7) by welding.

6. The electric heating device for heating a liquid with a pipe according to claim 4, characterized by, The liquid guide tube (2) is bent in a U-shape inside the water tank (8).

7. The electric heating device for heating a liquid with a pipe according to claim 1, wherein It also includes a controller (9), a first temperature sensor (16), and a second temperature sensor (17). The first temperature sensor (16) is used to detect the liquid temperature at the inlet end of the liquid guide tube (2), and the second temperature sensor (17) is used to detect the liquid temperature at the outlet end of the liquid guide tube (2). The temperatures detected by the first temperature sensor (16) and the second temperature sensor (17) are transmitted to the controller (9). The controller (9) is also connected to the sheet heating assembly (1). The controller (9) controls the heating power of the sheet heating assembly (1) according to the temperatures detected by the first temperature sensor (16) and the second temperature sensor (17).

8. The electric heating device for heating a liquid with a pipe according to claim 1, characterized by, The sheet-shaped heating component (1) and the liquid guide tube (2) are in surface contact.

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