Heating device

Abstract

A heating device includes a heating component, the heating component includes a heating tube, a guide device and a cover shell, the guide device is sleeved on the outer circumference of the heating tube, the cover shell is sleeved on the outer circumference of the guide device, the inner cavity of the heating tube forms a connecting channel, the heating component also includes a first guide channel, the first guide channel is formed between the heating tube and the guide device, the guide device includes a connecting hole, the connecting hole can connect the first guide channel and the cavity formed by the cover shell; the fluctuation of water temperature is reduced, and the flow speed is more stable.

Description

Technical Field

[0001] The invention relates to household equipment technology, in particular to a heating device. Background Art

[0002] Generally, a heating device needs to heat the flowing liquid. The heating device includes a heating component. The heating component includes a heating tube and a flow guide device. How to set the heating component to enhance or improve the heating efficiency is a technical problem. Summary of the invention

[0003] An object of the present invention is to provide a heating device which is beneficial to improving heating efficiency.

[0004] An embodiment of the present invention provides a heating device, comprising a heating component, wherein the heating component comprises a heating tube, a flow guide device and a cover shell, wherein the flow guide device is sleeved on the outer circumference of the heating tube, and the cover shell is sleeved on the outer circumference of the flow guide device, wherein a first connecting channel is formed in the inner cavity of the heating tube, wherein the first connecting channel connects the inlet of the heating tube with the outlet of the heating tube, and a flow guide channel is formed between the heating tube and the flow guide device, wherein the flow guide channel connects the outlet of the heating tube with the outlet of the flow guide device; wherein the flow guide device comprises a main body, a first protrusion and a first recess, wherein the first protrusion and the first recess are located on the inner circumference of the main body, wherein the first protrusion is arranged at intervals along the axial direction of the flow guide device, wherein the first protrusion is located between adjacent recesses, and wherein the flow guide channel comprises a channel formed by the first recess and the outer wall of the heating tube; wherein the flow guide device further comprises a connecting hole, wherein the connecting hole is located between adjacent first protrusions, wherein the connecting hole is located at the bottom of the first recess, and wherein the connecting hole can connect the flow guide channel with the cavity formed by the cover shell.

[0005] The heating device of the technical solution of the present invention is provided with a heating tube, a flow guide device and a cover shell, and a flow channel is formed between the heating tube, the flow guide device and the cover shell. By improving the flow guide device and redesigning the water flow channel, the water flow is made more uniform, the fluctuation of water temperature is reduced, and the flow speed is made more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] With reference to the accompanying drawings, further objects, functions and advantages of the present invention will be clarified through the following description of embodiments of the present invention, in which:

[0007] Figure 1 A schematic diagram of the three-dimensional structure of the heating device in this embodiment from one viewing angle;

[0008] Figure 2 for Figure 1 A schematic diagram of the main structure of the heating device;

[0009] Figure 3 for Figure 1 A schematic diagram of an exploded structure of a heating device;

[0010] Figure 4 for Figure 1 A schematic diagram of a top view of the structure of a heating device;

[0011] Figure 5 for Figure 4 AA cross-sectional structure diagram in;

[0012] Figure 6 for Figure 4 Schematic diagram of BB cross-section structure;

[0013] Figure 7 for Figure 4 Schematic diagram of CC cross-section structure;

[0014] Figure 8 for Figure 2 Schematic diagram of HH cross-section structure;

[0015] Fig. 9 for Figure 2 A schematic diagram of a three-dimensional structure of a diversion device from one perspective;

[0016] Fig.10 for Fig. 9 A left-side structural schematic diagram of a flow guide device;

[0017] Fig.11 for Fig.10 A schematic diagram of the three-dimensional structure of the first guide part from one perspective;

[0018] Fig.12 for Fig.11 A left-side structural schematic diagram of the first guide portion;

[0019] Fig.13 for Figure 2 A schematic diagram of the three-dimensional structure of the middle cover from one viewing angle;

[0020] Fig.14 for Fig.11 A schematic diagram of the structure of the cover from top view;

[0021] Fig.15 for Fig.14 Schematic diagram of the EE cross-section structure;

[0022] Fig.16 A schematic block diagram of a connection method of a first embodiment of a heating device;

[0023] Fig.17 It is a schematic block diagram of the connection method of the first embodiment of the heating device. DETAILED DESCRIPTION

[0024] In order to make the technical solution of the present invention clearer and more understandable, the present invention will be described in detail below with reference to the accompanying drawings and in combination with specific embodiments. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0025] Fig.16 and Fig.17 The schematic block diagram shows the connection mode of two embodiments of the heating device according to the present invention. The heating device 100 includes a water inlet temperature sensor 101, a heating component 102, and a water outlet temperature sensor 104 according to the water flow direction; the heating device 100 also includes a flow meter 103, which can be located before the water outlet temperature sensor 104 or after the water outlet temperature sensor 104, wherein Fig.16 In the embodiment, the flow metering unit 103 is located before the outlet water temperature sensor 104, so that the temperature of the water flowing out of the outlet pipe can be controlled more accurately. Fig.17 In the embodiment, the flow metering unit 103 is located after the outlet water temperature sensor 104, so that the flow rate of water flowing out of the outlet pipe can be controlled more accurately; the water flow direction is from the water inlet to the water outlet.

[0026] See also Fig.16 The flow metering unit 103 is a device for adjusting the flow of the water outlet, and its water inlet is connected to the water outlet of the heating component 102. The water outlet of the flow metering unit 103 is connected to the water inlet of the water outlet temperature sensor 104.

[0027] The heating assembly 102 is a device for heating water, and its water inlet is connected to the water outlet of the water inlet temperature sensor 101, and its water outlet is connected to the water inlet of the flow metering unit 103. The heating assembly 102 includes a heating tube 102A and a flow guide device 102B. The heating tube 102A includes an electric heating element and an insulating layer, and the insulating layer is used to isolate the heating element from the liquid. The flow guide device 102B does not directly contact the heating tube 102A.

[0028] The outlet water temperature sensor 104 is a sensor for detecting the outlet water temperature, and its water inlet is connected to the outlet water of the flow metering unit 103. The outlet water temperature sensor 104 is a sensor that can sense temperature and convert it into a usable output signal. The above inlet water temperature sensor 101 and temperature sensor 104 can be a thermal resistor type or a thermocouple type.

[0029] The heating device 100 also includes a circuit control board 105 for controlling the entire heating device. The circuit control board 105 can be an MCU control circuit board. The circuit control board 105 includes a flow control unit 104A for controlling the flow regulator 103, a power control unit 104B for controlling the power of the heating component 102, and an outlet water temperature control unit 104C for controlling the outlet water temperature sensor 104, and an inlet water temperature control unit 104D for controlling the inlet water temperature sensor 101. In addition, the circuit control board 105 also includes a serial communication port for receiving external commands, and a control unit for controlling a high-power thyristor or IGBT device, and so on.

[0030] With the heating device of this exemplary embodiment, the user only needs to connect the water inlet pipe, the water outlet pipe, and the power supply with a pipeline to heat, and the heating temperature is set through the communication port. The system integration manufacturer only needs to select the heating device of the present invention and simply configure the water circuit and the circuit to complete the assembly of the finished product. Therefore, the heating device is an intelligent instant heating module, which is plug-and-play, safe, reliable, and easy to use.

[0031] A heating device 100 according to an embodiment of the present invention comprises a heating assembly 102, wherein the heating assembly 102 comprises a heating tube 102A, a flow guide device 102B and a cover 102C, wherein the flow guide device 102B is sleeved on the outer periphery of the heating tube 102A, and the cover 102C is sleeved on the outer periphery of the flow guide device 102B, and the heating assembly 102 has a first connecting channel 21 and a flow guide channel 22, wherein the first connecting channel 21 connects the heating tube inlet 23 and the heating tube outlet 24, and the flow guide channel 22 is located between the heating tube 102A and the flow guide device 102B, and the flow guide channel 22 connects the heating tube outlet 24 and the outlet of the flow guide device; the flow guide device 102B comprises a main body 11, a first protruding portion 12 and a first recessed portion 13, wherein the thickness of the first protruding portion is the same as that of the main body, and the first protruding portion is a part of the main body; the first protruding portion 12 and the first recessed portion 13 Located at the inner circumference of the guide device, the first protrusions 12 are arranged at intervals along the axial direction of the guide device 102B, and the first protrusions 12 are provided between adjacent first recesses 13. The guide flow channel 22 includes the first recess 13 and the channel formed by the outer wall of the heating tube; the guide device 102B also includes a connecting hole 14, which can connect the guide channel and the cavity formed by the cover, that is, the connecting hole can connect the inside and outside of the guide device, and the connecting hole 14 is located between adjacent first protrusions 12. The connecting hole 14 is located at the bottom of the first recess 13, and each first recess has a connecting hole 14 at the bottom, which can better reduce the fluctuation of water temperature; by arranging the heating tube, the guide device and the cover, and forming a flow channel between the heating tube, the guide device and the cover, by improving the guide device and redesigning the water flow channel, the water flow is more uniform, the fluctuation of water temperature is reduced, and the flow velocity is warmer.

[0032] See also Fig.17 The heating device of this exemplary embodiment is Fig.16 The main difference of the illustrated heating device is that the flow regulator 103 is located after the water outlet temperature sensor 104. That is, in the present exemplary embodiment, the water inlet of the flow regulator 103 is communicated with the water outlet of the water outlet temperature sensor 104. In order to avoid redundancy, the description of the structures and functions of the present exemplary embodiment that are the same as those of the second exemplary embodiment is omitted here.

[0033] The following is for Fig.17 The specific structure of the heating device of the embodiment is exemplarily described; see Figures 1 to 3 The heating device 100 includes a water inlet temperature sensor 101, a heating component 102, a flow metering unit 103, a water outlet temperature sensor 104, a circuit control board 105, a mounting board 106, a water inlet pipe 107, and a water outlet pipe 108; the water inlet temperature sensor 101, the heating component 102, the flow metering unit 103, the water outlet temperature sensor 104, the circuit control board 105, and the water inlet pipe 107 are directly or indirectly fixedly connected to the mounting board 106, that is, the heating device is assembled into a whole through the mounting board 106. When the heating device is working, water enters from the water inlet pipe 107, the water inlet temperature sensor 101 detects the water temperature before entering the heating component, the heating component 102 heats the water, the water outlet temperature sensor 104 detects the water temperature after being heated by the heating component, and the water is connected to the flow metering unit 103 through the channel connected to the water outlet temperature sensor, and the water passing through the flow metering unit 103 enters the water outlet pipe 108, and the water flows out of the heating device from the water outlet pipe 108.

[0034] See also Figure 3 and Figure 5 The heating assembly 102 includes a heating tube 102A and a flow guide device 102B. The flow guide device 102B is located at the periphery of the heating tube 102A. The heating tube 102A and the flow guide device 102B are not in direct contact. There is a gap between the heating tube 102A and the flow guide device 102B. The minimum spacing between the heating tube 102A and the flow guide device 102B is greater than 0, which can reduce the influence of the temperature of the heating tube on the flow guide device. The heating assembly 102 also includes a cover 102C, which is sleeved on the periphery of the flow guide device 102B. The flow guide device 102B is limited by the cover 102C or the flow guide device 102B is fixedly connected to the cover 102C. In this way, the cover 102C is separately provided to seal the heating assembly, which is conducive to the simplification of the mold.

[0035] The heating device 100 has a first connecting channel 21, which is formed on the heating tube. The heating tube has a heating tube inlet 23 and a heating tube outlet 24, and the heating tube inlet 23 and the heating tube outlet 24 are connected through the first connecting channel 21; the heating tube 102A includes a limiting portion 25 and a base 26, and the first connecting channel 21, the heating tube inlet 23, and the heating tube outlet 24 are formed on the base 26. The limiting portion 25 is a flange formed on the base 26, and the outer diameter of the flange is larger than the outer diameter of the base 26; the cover 102C abuts against the limiting portion 25 and is sealed at the connection, and one end face of the guide device 102B is axially limited in the cavity of the cover 102C by the limiting portion 25, and the limiting portion 25 is sealed with the cover.

[0036] See also Fig. 9 and Fig.10 The flow guide device 102B is cylindrical, and the flow guide device 102B includes an integrally-injected first flow guide portion 10 and an integrally-injected second flow guide portion 20. The first flow guide portion 10 and the second flow guide portion 20 are symmetrically arranged. The first flow guide portion 10 and the second flow guide portion 20 are both in the shape of an arc surface. After the second flow guide portion 10 and the second flow guide portion 20 are assembled, they enclose and form an inner cavity of the flow guide device. In this embodiment, the first flow guide portion 10 is used for illustration.

[0037] Combination Fig.11 and Fig.12The first guide portion 10 includes a body portion 11, a first protrusion 12, a first recess 13, a connecting hole 14, a second protrusion 15, a second recess 16, a first end protrusion 17, and a second end protrusion 18, wherein the first protrusion 12, the first recess 13, the first end protrusion 17, and the second end protrusion 18 are located on the inner side of the body portion 11, the second protrusion 15 and the second recess 16 are located on the outer side of the body portion 11, the first end protrusion 17 is close to one end of the body portion 11, and the second end protrusion is close to the other end of the body portion 11, the first protrusion 12 is arc-shaped, extending along the circumferential direction of the body portion 11, the first protrusion 12 is spaced apart along the axial direction of the body portion 11, the first recess 13 is formed between adjacent first protrusions 12, the first protrusion 12 and the first end protrusion 17 are arranged at intervals along the axial direction of the body portion 11, and the first recess 13 is formed between adjacent first protrusions 12. The first protrusion 12 and the first end protrusion 17 are arranged at intervals, a part of the first concave portion 13 is formed between the first protrusion 12 and the second end protrusion 18, the first end protrusion 17 and the second end protrusion 18 are arranged in parallel, the first protrusion 12 and the first end protrusion 17 are arranged obliquely or at an acute angle; the first protrusion 12 is arranged obliquely relative to the first end protrusion 17, and the angle between the first protrusion 12 and the first end protrusion 17 is greater than or equal to 15° and less than or equal to 45°; preferably 25°; the smaller the angle, the water flow in the first concave is blocked, causing most of the water to overflow the first protrusion, and the larger the angle, the shorter the guide channel; both cannot play a good guide role. The range selected in this embodiment can take into account the above problems and is conducive to improving the heat exchange efficiency. ; The first end protrusion 17 and the second end protrusion 18 are both half arc-shaped. The communication hole 14 is located between the first concave portion 13 and the adjacent first convex portion 12, and each first concave portion 13 corresponds to one communication hole 14, that is, the communication hole 14 passes through the main body portion 11. The communication hole is provided so that the water flow in part of the first concave portion can enter the inner cavity of the housing, and the side wall of the main body forming the communication hole generates a small turbulence, thereby reducing the temperature fluctuation of the heat exchanger and further improving the heat exchange efficiency.

[0038] The minimum distance between the first protrusion 12 of the heating tube 102A and the guide device 102B is less than 2 mm or 1 mm or less than 0.6 mm or less than 0.5 mm or less than 0.4 mm, which helps to reduce the flow of water through the gap between the first protrusion and the heating tube, allowing the water to flow along the first recess, increasing the path of the water flow and improving the heating efficiency.

[0039] The second protrusions 15 extend along the axial direction of the main body 11, and adjacent second protrusions 15 are spaced apart along the axial direction of the main body 11. Second recesses 16 are formed between adjacent second protrusions 15. In this embodiment. Fig.10 and Fig.11The height H1 of the first protrusion is less than the height H2 of the second protrusion; this is conducive to improving the cover body through the second protrusion limit guide device, and the low height of the first protrusion is conducive to the miniaturization of the guide channel, so that the path of the water flow is increased, which is conducive to improving the heat exchange efficiency. At least part of the second protrusion 15 contacts the inner wall of the cover shell, and the second recessed part and the inner wall of the cover shell form a second communication channel, that is, the cavity of the cover shell.

[0040] The guide device 102B includes a connecting groove 19. The connection between the first guide part 10 and the second guide part 20 is located at the bottom of the connecting groove 19. The depth of the connecting groove 19 is less than the depth of the second recess 16. This facilitates the limiting of the first guide part and the second guide part relative to the cover shell. Of course, when the first guide part and the second guide part need to be connected as one, they can be connected at the connecting groove without affecting the external dimensions of the guide device.

[0041] See also Figure 1 and Figure 3 as well as Figures 7 to 15 , the housing 102C is integrally formed, the heating device 100 includes a first mounting portion 31, a second mounting portion 32 and a connecting portion 33. In this embodiment, the outlet water temperature sensor 104 is assembled through the first mounting portion 31, the first mounting portion 31 is integrally formed with the housing 102C, the flow metering portion 103 is assembled through the second mounting portion 32, the second mounting portion 32 is integrally formed with the housing 102C, the outlet water pipe 108 is integrally formed with the second mounting portion 32, the first mounting portion 31 and the second mounting portion 32 are connected through the connecting portion 33, the first mounting portion 31 is formed with a first mounting cavity 311, the second mounting portion 32 is formed with a second mounting cavity 321, and at least the induction head of the outlet water temperature sensor 104 extends into the first mounting cavity 311. Figure 6 , Figure 7The connecting portion 33 has a connecting channel 331, which connects the first installation cavity 311 and the second installation cavity 321. The first installation cavity 311 passes through the inner and outer surfaces of the housing 102C. The first installation cavity 311 is connected to the second connecting channel through the connecting hole 14, and the second installation cavity 321 is not directly connected to the second connecting channel. The connecting portion of the connecting channel 331 and the first installation cavity 311 is located behind the sensing head of the outlet water temperature sensor to ensure the temperature accuracy. Of course, if the temperature accuracy requirement is not high, in order to improve the fluidity, the connecting portion of the connecting channel 331 and the first installation cavity 311 is located between the sensing head and the connecting hole of the outlet water temperature sensor. The distance between the sensing head and the inner wall of the housing is less than or equal to 4 mm and greater than or equal to 1 mm. The extension direction of the first installation cavity 311 is perpendicular to the extension direction of the connecting channel 331. The connecting channel 331 is arranged in an extending direction parallel to the axial direction of the heating component; the water outlet pipe 108 is connected to the second installation cavity 321, the flow metering part 103 includes a flow metering element 41, the flow metering element 41 is located in the second installation cavity 321, and the temperature insurance device 42 is located outside the second installation cavity 321. The flow metering part 103 also includes a cover plate 43, the cover plate 42 is connected to and sealed with the second installation part 32, the second installation cavity 321 is located on one side of the cover plate 43, and the temperature insurance device 42 is located on the other side of the cover plate 43. In this embodiment, the cover plate 43 is screwed to the second installation part 32 and sealed by a sealing ring, with a simple structure and low cost.

[0042] See also Fig.13 and Fig.14 The cover 102C also includes a combination part 33, which includes an inner step 331 and an outer step 332. The outer edge size of the outer step is larger than the outer edge size of other parts of the cover. The inner step 331 is the inner wall of the cover. The step surface of the inner step 331 abuts against and limits the limiting part 25 of the heating tube.

[0043] The housing 102C further includes a third protrusion 34 and a third recess 35. The third protrusion 34 extends along the axial direction of the housing. The third protrusions 34 are arranged at intervals along the circumference of the inner cavity of the housing. The third recesses 35 are located between adjacent third protrusions 34. The second protrusion 15 can be limited to the third recess 35. The third protrusion 34 can extend into the second recess 16. The second protrusion 15 is tightly matched or loosely matched with the housing or the third protrusion 34 is tightly matched or loosely matched with the flow guide device. The third protrusion and the third recess of the housing cooperate with the second protrusion and the second recess of the flow guide device to limit the rotation displacement of the flow guide device relative to the housing. In order to facilitate demoulding, the side walls of some adjacent second protrusions are arranged in parallel.

[0044] The heating device 100 also includes a cover body 50, which is fixedly connected to the cover shell 102C. The cover body 50 includes a third mounting portion 51, and the water inlet temperature sensor 101 is installed on the third mounting portion 51; the water inlet pipe 107 of the heating device is integrally formed with the cover body 50; the cover body 50 has a buffer cavity 52, and the water inlet pipe 107 is connected to the first connecting channel 21 of the heating component through the buffer cavity 52.

[0045] In this embodiment, the first mounting portion 31, the second mounting portion 32, the third mounting portion 51, and the water outlet pipe 108 are located on the same side of the heating device 100, and the water inlet temperature sensor 101, the water outlet temperature sensor 104, and the flow metering portion 103 are installed in the same direction, which is conducive to realizing automated installation and preventing installation interference; the water outlet pipe 108 extends in a direction parallel to the axial direction of the heating component; the water inlet pipe 107 is located on the top of the cover body 50 and extends toward the top of the heating device.

[0046] It should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the present invention has been described in detail in this specification with reference to the above embodiments, it should be understood by those skilled in the art that the present invention can still be modified or replaced by equivalents, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A heating device, comprising a heating assembly, wherein the heating assembly comprises a heating tube, a flow guide device and a cover, wherein the flow guide device is sleeved on the outer circumference of the heating tube, and wherein: The cover shell is sleeved on the outer circumference of the flow guide device, and the inner cavity of the heating tube forms a first communication channel, the first communication channel connects the inlet of the heating tube and the outlet of the heating tube, and a flow guide channel is formed between the heating tube and the flow guide device, and the flow guide channel connects the outlet of the heating tube and the outlet of the flow guide device; the flow guide device includes a body, a first protrusion and a first recess, the first protrusion and the first recess are located on the inner circumference of the flow guide device, the first protrusion is arranged at intervals along the axial direction of the flow guide device, the first protrusion is located between adjacent first recesses, and the flow guide channel includes a channel formed by the first recess and the outer wall of the heating tube; The flow guiding device further comprises a connecting hole, wherein the connecting hole is located between adjacent first protrusions, the connecting hole is located at the bottom of the first recess, and the connecting hole can connect the flow guiding channel and the cavity formed by the cover shell; The flow guide device further includes a second protrusion and a second recess, the second protrusion and the second recess are located at the outer periphery of the main body, the second recess is located between adjacent first protrusions, the second protrusions are arranged along the circumference of the flow guide device, the second protrusions extend along the axial direction of the flow guide device, and the communicating hole passes through the bottom of a portion of the second recess; At least part of the second protrusion contacts the inner wall of the housing, and the second recess and the inner wall of the housing form a second communication channel; The minimum distance between the outer wall of the heating tube and the first protrusion of the flow guide device is less than 2 mm or 1 mm or less than 0.6 mm or less than 0.5 mm or less than 0.4 mm.

2. The heating device according to claim 1, characterized in that: The cover shell includes a third protrusion and a third recess, the third protrusion extends along the axial direction of the cover shell, the third protrusions are arranged at intervals along the circumference of the inner cavity of the cover shell, and the third recesses are located between adjacent third protrusions; the second protrusion can be limited to the third recess, the third protrusion can extend into the second recess, the second protrusion is tightly fitted or loosely fitted with the cover shell or the third protrusion is tightly fitted or loosely fitted with the guide device, the third protrusion and the third recess of the cover shell cooperate with the second protrusion and the second recess of the guide device to limit the rotational displacement of the guide device relative to the cover shell.

3. The heating device according to claim 2, characterized in that: The height of the second protrusion is greater than that of the first protrusion, and the distance from the top of the third protrusion to the bottom of the second recess is less than or equal to the distance from the first protrusion to the outer wall of the heating tube.

4. The heating device according to any one of claims 1 to 3, characterized in that: The flow guide device comprises a first flow guide portion and a second flow guide portion formed by integral injection molding. After the first flow guide portion and the second flow guide portion are combined, at least a portion of the first protrusion is butted against each other, and the first recess forms a continuous flow guide channel.

5. The heating device according to claim 4, characterized in that: The first guide portion and the second guide portion are welded and fixed, the guide device comprises a connecting groove, the connection between the first guide portion and the second guide portion is located in the connecting groove, and the depth of the connecting groove is less than the depth of the second recess.

6. The heating device according to claim 5, characterized in that: The guide device also includes a first end protrusion and a second end protrusion, the first end protrusion and the second end protrusion are located on the inner circumference of the main body, the first end protrusion is located at one end of the guide device, and the second end protrusion is located at the other end of the guide device, the first end protrusion and the second end protrusion are cylindrical, wherein the outer end of the first end protrusion abuts or has a clearance fit with the heating tube, and the outer end of the second end protrusion abuts or has a clearance fit with the cover shell.

7. The heating device according to claim 6, characterized in that: The first protrusion is inclined relative to the first end protrusion, and an angle between the first protrusion and the first end protrusion is greater than or equal to 15° and less than or equal to 45°.

8. The heating device according to claim 7, characterized in that: The heating tube includes a base and a limiting portion, the base forms an inner cavity of the heating tube, the limiting portion is a flange formed on the base, the outer diameter of the flange is larger than the outer diameter of the base, the cover shell abuts against the flange and is sealed at the connection, and the outer end surface of the first end protrusion of the guide device is axially limited in the inner cavity of the cover shell by the limiting portion.

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