Downdraft prevention mechanism and gas water heating equipment

Abstract

The utility model relates to the technical field of gas water heating equipment, in particular to an anti-downdraft mechanism and gas water heating equipment. The down draft preventing mechanism comprises a chimney, a connecting cylinder, a wind blocking assembly, a fixing frame and an electromagnetic assembly. According to the embodiment of the utility model, the electromagnetic component is arranged, so that the wind shielding component can be controlled to open and close the chimney by virtue of magnetic force generated by the electromagnet. When the gas water heating equipment is used, the electromagnetic assembly operates and generates magnetic force, the wind shielding cover is attracted to the fixing frame and fixed, and at the moment, waste gas can enter the chimney from the connecting cylinder and the via hole in sequence. Therefore, the smoke can be prevented from driving the air blocking assembly to shake when flowing. And after the gas water heating equipment is used, the electromagnetic assembly stops operating, the magnetic force disappears, the fixing frame is separated from the wind shielding cover, and the wind shielding assembly is sleeved with the connecting cylinder again, so that the chimney is closed.

Description

Technical Field

[0001] This utility model relates to the field of gas equipment technology, specifically to an anti-backdraft mechanism and a gas-fired hot water equipment. Background Technology

[0002] Currently, some gas-fired water heating systems used by users require exhaust pipes to vent smoke outdoors during operation, such as gas water heaters and wall-mounted boilers. In winter, cold outdoor air can flow directly back into the equipment through the exhaust pipes, causing the heat exchanger pipes inside the equipment to freeze and crack, resulting in many problems for both manufacturers and users.

[0003] To prevent backdraft, an anti-backdraft mechanism is typically installed inside the exhaust duct. When the gas-fired water heater is operating, this mechanism opens the exhaust duct under the influence of flue gas, ensuring that exhaust gases can be properly discharged outdoors. However, after the exhaust duct is opened, the existing anti-backdraft mechanism vibrates significantly with the flow of flue gas. This not only affects the stability of the mechanism itself but also transmits the vibration to adjacent components, generating considerable noise. Furthermore, when the gas-fired water heater stops operating, the anti-backdraft mechanism closes the exhaust duct. However, because there is a gap between the anti-backdraft mechanism and the exhaust duct, some cold outdoor air can flow into the gas-fired water heater through this gap, thus affecting the indoor temperature. Utility Model Content

[0004] In view of this, the present invention provides an anti-backdraft mechanism and a gas-fired water heater to solve the problems of noise generation and poor sealing caused by the anti-backdraft mechanism.

[0005] In a first aspect, this utility model provides an anti-backdraft mechanism, which includes:

[0006] Chimney;

[0007] A connecting cylinder, at least partially located within the inner cavity of the chimney, is sealed to the chimney;

[0008] A windbreak assembly includes a windbreak cylinder and a windbreak cover connected to each other. The windbreak cylinder is movably inserted into the connecting cylinder. The windbreak cover is located at the end of the windbreak cylinder away from the connecting cylinder and is used to seal the downstream opening of the connecting cylinder. A through hole is formed on the side wall of the windbreak cylinder, and the windbreak cover has a magnetic attraction part.

[0009] A fixing bracket is disposed inside the chimney cavity; along the flow direction of the flue gas, the fixing bracket is located downstream of the windshield cover;

[0010] An electromagnet is mounted on the aforementioned fixed frame;

[0011] The controller is electrically connected to the electromagnet;

[0012] When the wind deflector moves upward and opens the opening as the gas-fired water heater operates, the wind deflector contacts the fixing frame. The controller controls the electromagnet to be energized to attract and fix the magnetic suction part. The through hole is connected to the inner cavity of the chimney.

[0013] Beneficial effects: When the gas water heater is running, the baffle moves upward with the flue gas, opening the downstream opening of the connecting cylinder, allowing the flue gas to flow into the connecting cylinder through the through hole. Simultaneously, the baffle contacts the mounting bracket, and the controller energizes the electromagnet on the mounting bracket, magnetically attaching the baffle to the bracket. Because the baffle is firmly fixed to the bracket by magnetism, it does not vibrate significantly with the flow of flue gas, thus reducing the noise of the anti-backdraft mechanism. When the gas water heater stops running, the controller de-energizes the electromagnet. Since the baffle is movably inserted into the connecting cylinder, the baffle falls back down under gravity, re-closing the upstream opening of the connecting cylinder, closing the flue gas passage, and effectively preventing backdraft. Because the windshield is connected to the windshield tube, the windshield and windshield tube together are heavier than conventional hinged backdraft windshields, and the pressure required to close them is greater. In addition, the windshield tube is fitted with the connecting tube in a plug-in manner, so it is not easy for the windshield to be blown open by the turbulence caused by backflow and flow into the depth of the flue through the gap, thus resulting in better sealing.

[0014] In one alternative embodiment, the windshield is at least partially made of a ferromagnetic material or a permanent magnet to form the magnetic attraction portion.

[0015] In one optional embodiment, a sealing ring is further included, which is sleeved and fixed to the connecting cylinder, and the connecting cylinder is sealed to the chimney through the sealing ring.

[0016] In one alternative embodiment, the sealing ring comprises:

[0017] The bottom wall of the windshield is provided with a first annular inclined surface, and the top of the connecting cylinder is provided with an outwardly expanding second annular inclined surface, and the first annular inclined surface and the second annular inclined surface abut against each other.

[0018] In one alternative embodiment, the mounting bracket includes:

[0019] A support plate, on which the electromagnet is fixed;

[0020] Multiple connecting strips, one end of which is connected to the support plate and the other end of which is connected to the inner wall of the chimney.

[0021] In one alternative embodiment, a plurality of the connecting strips are evenly and radially distributed around the support plate.

[0022] In one alternative embodiment, a fixing shell is provided on the support plate, and the electromagnet is installed inside the fixing shell.

[0023] In one optional embodiment, the mounting bracket further includes:

[0024] A reinforcing rib is provided on the connecting strip and extends along the length of the connecting strip.

[0025] In one optional embodiment, the support plate is provided with a contact convex surface, the electromagnet is provided on the back side of the contact convex surface, and when the windshield is opened, the magnetic part abuts against the contact convex surface.

[0026] Secondly, this utility model also provides a gas-fired water heater, which includes: a flue pipe and an anti-backdraft mechanism as described in any of the above embodiments, wherein the flue pipe is connected to the chimney of the anti-backdraft mechanism.

[0027] When the gas-fired water heater of this application is running, the baffle cover moves upward with the flue gas, opening the downstream opening of the connecting cylinder, allowing the flue gas to flow into the connecting cylinder through the through hole. Simultaneously, the baffle cover contacts the mounting bracket, and the controller energizes the electromagnet on the mounting bracket, magnetically attaching the baffle cover to the bracket. Because the baffle cover is firmly magnetically fixed to the bracket, it does not vibrate significantly with the flow of flue gas, thus reducing the overall noise of the gas-fired water heater. When the gas-fired water heater stops running, the controller de-energizes the electromagnet. Since the baffle cylinder is movably inserted into the connecting cylinder, the baffle cover can fall down under gravity, re-closing the upstream opening of the connecting cylinder, closing the flue gas passage, and preventing backdraft. Because the baffle cover is connected to the baffle cylinder, compared to conventional hinged backdraft prevention baffle covers, the overall weight of the baffle cover and baffle cylinder is greater, resulting in greater closing pressure. Furthermore, the baffle cylinder's insertion method with the connecting cylinder makes it less susceptible to being blown open by turbulence caused by backdraft, thus providing better sealing. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of this utility model, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is an exploded view of the anti-backdraft mechanism in an embodiment of this utility model;

[0030] Figure 2 for Figure 1 A schematic diagram of the center windshield assembly and mounting bracket in another direction;

[0031] Figure 3 This is a top view of the fixing frame in the chimney in an embodiment of the present invention;

[0032] Figure 4 This is a cross-sectional view of the anti-backdraft mechanism in the closed state in an embodiment of this utility model;

[0033] Figure 5 for Figure 4 An enlarged schematic diagram of part A in the middle;

[0034] Figure 6 This is a cross-sectional view of the anti-backdraft mechanism in the open state in an embodiment of this utility model;

[0035] Figure 7 for Figure 6 Enlarged schematic diagram of part B.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Chimney; 2. Connecting tube; 21. Second annular inclined surface; 3. Windproof assembly; 31. Windproof tube; 32. Windproof cover; 321. First annular inclined surface; 322. Magnetic suction part; 33. Through hole; 4. Fixing frame; 41. Support plate; 411. Contact convex surface; 42. Fixing shell; 43. Connecting strip; 5. Sealing ring; 6. Receiver base; 7. Receiver; 8. Electromagnet. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0040] According to an embodiment of the present invention, an anti-backdraft mechanism is provided for use in a gas-fired water heater. The anti-backdraft mechanism includes a chimney 1, a connecting cylinder 2, a windbreak assembly 3, a fixing frame 4, an electromagnet 8, and a controller.

[0041] Specifically, in the embodiments of this utility model, such as Figure 1 As shown, chimney 1 is suitable for connection to the exhaust pipe of a gas-fired hot water system. The exhaust pipe of the gas-fired hot water system is used to discharge exhaust gas. Chimney 1 can be connected to the exhaust pipe or it can be part of the exhaust pipe itself. When chimney 1 is connected to the exhaust pipe, chimney 1 can be directly sleeved onto the exhaust pipe, or chimney 1 and the exhaust pipe can be directly welded together by covering them with sheet metal.

[0042] Of course, this embodiment is merely an example of the connection method between the chimney 1 and the exhaust pipe, but it does not limit the scope of the invention. Those skilled in the art can make changes according to the actual situation, as long as the same technical effect can be achieved.

[0043] Furthermore, in the embodiments of this utility model, such as Figure 1 As shown, the connecting cylinder 2 is at least partially located within the inner cavity of the chimney 1. The connecting cylinder 2 is sealed to the chimney 1, meaning that the outer diameter of the connecting cylinder 2 within the inner cavity of the chimney 1 is smaller than the inner diameter of the chimney 1. In other words, the connecting cylinder 2 can be directly fitted inside the chimney 1, and the outer wall of the connecting cylinder 2 is sealed to the inner wall of the chimney 1. The connecting cylinder 2 and the chimney 1 together form a sleeve structure. In actual operation, after the exhaust gas from the gas-fired water heater enters the chimney 1, it can only be discharged outwards through the connecting cylinder 2.

[0044] For the sealed connection between the outer wall of the connecting cylinder 2 and the inner wall of the chimney 1, a sealing element can be provided between the outer wall of the connecting cylinder 2 and the inner wall of the chimney 1, and the sealing element is fitted onto the connecting cylinder 2.

[0045] Furthermore, in the embodiments of this utility model, such as Figure 1 , Figure 2 , Figure 4 , Figure 6 As shown, the windbreak assembly 3 includes a windbreak duct 31 and a windbreak cover 32, which are connected to each other. The windbreak duct 31 is movably inserted into the connecting cylinder 2. Specifically, the windbreak duct 31 can be inserted into the connecting cylinder 2, or conversely, the windbreak duct 31 can be sleeved on the outer wall of the connecting cylinder 2, both forming a telescopic cylinder structure. In actual operation, the windbreak duct 31 has a first position where it is fully inserted into the connecting cylinder 2 and a second position where it is partially extended out of the connecting cylinder 2. The windbreak duct 31 can only extend partially out of the connecting cylinder 2; if it extends fully out of the connecting cylinder 2, it may detach from the connecting cylinder 2 and fall off.

[0046] Furthermore, the wind deflector 32 is disposed at the end of the wind deflector 31 away from the connecting cylinder 2, and the wind deflector 32 is used to cover the downstream opening of the connecting cylinder 2. The downstream refers to the downstream direction of the overall flue gas passage. A through hole 33 is provided on the side wall of the wind deflector 31.

[0047] In this way, during actual operation, after the gas-fired water heater generates exhaust gas that enters the connecting cylinder 2, the baffle cover 32 seals the connecting cylinder 2. Therefore, when the exhaust gas is discharged outward, it can only push the baffle assembly 3 along the length of the connecting cylinder 2 until the through hole 33 on the baffle cylinder 31 protrudes from the connecting cylinder 2. Thus, the exhaust gas can enter the chimney 1 through the through hole 33 and then be discharged outward. When the gas-fired water heater stops working, exhaust gas is no longer generated, and the baffle assembly 3 falls back into the connecting cylinder 2, thereby sealing the chimney 1.

[0048] Furthermore, the windshield cover 32 has a magnetic suction part 322, and the fixing frame 4 is disposed in the inner cavity of the chimney 1. Along the flow direction of the flue gas, the fixing frame 4 is located downstream of the windshield cover 32. An electromagnet 8 is disposed on the fixing frame 4, and the controller is electrically connected to the electromagnet 8.

[0049] In actual operation, when the wind deflector 32 moves upward and opens the opening as the gas water heater operates, the wind deflector 32 contacts the fixing frame 4. The controller controls the electromagnet 8 to be energized to attract and fix the magnetic suction part 322. The through hole 33 is connected to the inner cavity of the chimney 1.

[0050] With this configuration, when the gas water heater is running, the baffle 32 moves upward with the flue gas, opening the downstream opening of the connecting cylinder 2, allowing the flue gas to flow into the connecting cylinder 2 through the through hole 33. Simultaneously, the baffle 32 contacts the fixing frame 4, and the controller energizes the electromagnet 8 on the fixing frame 4, magnetically attaching the baffle 32 to the fixing frame 4. Because the baffle 32 is firmly magnetically fixed to the fixing frame 4, it will not vibrate significantly with the flow of flue gas, thus reducing the noise of the anti-backdraft mechanism. When the gas water heater stops running, the controller de-energizes the electromagnet 8. Since the baffle cylinder 31 is movably inserted into the connecting cylinder 2, the baffle 32 can fall down under gravity, re-closing the upstream opening of the connecting cylinder 2, closing the flue gas passage, and effectively preventing backdraft. Since the windshield cover 32 is connected to the windshield cylinder 31, compared with the conventional hinged anti-backdraft windshield cover 32, the windshield cover 32 and the windshield cylinder 31 are heavier as a whole, and the pressure of closing is greater. In addition, the windshield cylinder 31 is matched with the connecting cylinder 2 by a plug-in method, so it is not easy for the windshield cover 32 to be blown open by the turbulence caused by backdraft and flow into the depth of the flue through the gap, thus the sealing performance is better.

[0051] Furthermore, in an alternative embodiment, the windshield 32 is at least partially made of a ferromagnetic material or a permanent magnet to form the magnetic attraction portion 322. That is, the windshield 32 may be made entirely of a ferromagnetic material, or only a portion thereof. Alternatively, the windshield 32 may be made entirely of a permanent magnet, or only a portion thereof.

[0052] Specifically, permanent magnets are common types of rubidium magnets, AlNiCo magnets, or ferrite magnets, all of which are permanent magnets with their own magnetism; ferromagnetic components are common types of materials such as iron, cobalt, nickel, or cobalt-iron alloys, all of which are ferromagnetic components that do not have their own magnetism but can be attracted by magnets.

[0053] Furthermore, in an optional embodiment, the sealing ring 5 is sleeved and fixed to the connecting cylinder 2, and the connecting cylinder 2 is sealed to the chimney 1 through the sealing ring 5.

[0054] In this embodiment, the sealing ring 5 can be a silicone part or a rubber part. When the windshield cover 32 covers the connecting cylinder 2, the sealing ring 5 can seal the windshield cover 32 and the connecting cylinder 2.

[0055] With this configuration, the present invention embodiment, by setting a sealing ring 5, can achieve a sealed connection between the windproof cover 32 and the connecting cylinder 2 when the windproof cover 32 covers the connecting cylinder 2, thereby ensuring that the windproof cover 32 can stably seal the chimney 1 and prevent air leakage.

[0056] Furthermore, in an alternative implementation, such as Figure 5 As shown, the sealing ring 5 includes a first annular inclined surface 321 on the bottom wall of the windshield cover 32, and a second annular inclined surface 21 that expands outward on the top of the connecting cylinder 2. The first annular inclined surface 321 and the second annular inclined surface 21 abut against each other. (The first annular inclined surface 321 and the second annular inclined surface 21 are also mentioned.)

[0057] Specifically, in this embodiment, a first annular inclined surface 321 is disposed on the end face of the windshield 32 near the connecting cylinder 2; the first annular inclined surface 321 protrudes in the direction close to the connecting cylinder 2. A second annular inclined surface 21 is disposed on the top edge of the connecting cylinder 2, and the second annular inclined surface 21 expands outward along the radial direction of the connecting cylinder 2 to form a shape similar to a trumpet. When the windshield 32 covers the connecting cylinder 2, the first annular inclined surface 321 is embedded in the second annular inclined surface 21 and completely abuts against the inner wall of the second annular inclined surface 21.

[0058] In other words, the windshield 32 is pressed into a downward convex shape, and the top port of the connecting cylinder 2 is made into the shape of the second annular inclined surface 21. When the windshield 32 is fastened onto the connecting cylinder 2, the downward convex shape can be fastened onto the second annular inclined surface 21, thereby making the windshield 32 and the connecting cylinder 2 fit more tightly.

[0059] Furthermore, in an alternative implementation, such as Figures 1 to 4 , Figure 6 As shown, the fixing frame 4 includes a support plate 41 and multiple connecting strips 43.

[0060] Specifically, in this embodiment of the invention, the electromagnet 8 is fixed to the support plate 41. Alternatively, a fixing shell 42 can be provided on the support plate 41, and the electromagnet 8 can be installed inside the fixing shell 42. The support plate 41 can be a circular plate or a rectangular plate. This embodiment is merely an example of the structural type of the support plate 41 and is not intended to limit its application. Those skilled in the art can modify it according to actual circumstances to achieve the same technical effect.

[0061] Furthermore, one end of the connecting strip 43 is connected to the support plate 41, and the other end of the connecting strip 43 is connected to the inner wall of the chimney 1. This embodiment does not limit the number of connecting strips 43; those skilled in the art can modify them according to actual conditions to achieve the same technical effect.

[0062] Furthermore, in an alternative embodiment, a plurality of the connecting strips 43 are evenly and radially distributed around the support plate 41.

[0063] By configuring the connecting strip 43 in a radial structure, this embodiment of the invention avoids obstructing the flow of exhaust gas, ensuring that the exhaust gas can quickly pass through the chimney 1 and be discharged outwards, thus improving the exhaust gas discharge efficiency. Simultaneously, it also strengthens the overall structural strength of the support plate 41, ensuring that the support plate 41 can withstand the pressure of exhaust gas over a long period, extending the overall service life of the anti-backdraft mechanism.

[0064] Furthermore, in an optional embodiment, the fixing frame 4 further includes reinforcing ribs, which are disposed on the connecting strip 43 and extend along the length direction of the connecting strip 43.

[0065] The number and location of the reinforcing ribs can be modified by those skilled in the art according to actual conditions. The reinforcing ribs can be placed on both sides of the connecting strip 43 or around the periphery of the support plate 41, thereby strengthening the overall structure of the support plate 41. Of course, this embodiment is merely an example and is not intended to limit the scope. Those skilled in the art can modify it according to actual conditions as long as the same technical effect is achieved.

[0066] With this configuration, the overall structure of the support plate 41 can be further strengthened by adding reinforcing ribs, so that the support plate 41 can be stably attached to the inner wall of the chimney 1, preventing the support plate 41 from bending under the strong magnetic force of the electromagnet 8, thereby ensuring the normal operation of the anti-backdraft structure.

[0067] Furthermore, in an alternative implementation, such as Figure 7 As shown, the support plate 41 has a contact convex surface 411 on the end face near the windshield 32. The electromagnet 8 is located on the back of the contact convex surface 411. When the windshield 32 is opened, the magnetic attraction part 322 (8) abuts against the contact convex surface 411. By setting the contact convex surface 411, the effective contact area between the magnetic attraction part 322 and the windshield can be increased, making the part involved in magnetic attraction more targeted, improving the stability of the electromagnet's magnetic attraction, and avoiding interference from the connecting strip during the process of the electromagnet magnetically attracting the windshield, which would affect the stability of the magnetic attraction.

[0068] Furthermore, in an alternative implementation, such as Figure 1 As shown, the backdraft prevention mechanism also includes a receiving cylinder base 6 and a receiving cylinder 7. Along the exhaust direction, the receiving cylinder base 6 and the receiving cylinder 7 are located at the downstream port of the chimney 1. The receiving cylinder base 6 is spot-welded to the chimney 1, and the receiving cylinder 7 can also be spot-welded to the receiving cylinder base 6.

[0069] Secondly, this utility model also provides a gas-fired water heater, which includes: a flue pipe and an anti-backdraft mechanism as described in any of the above embodiments, wherein the flue pipe is connected to the chimney 1 of the anti-backdraft mechanism.

[0070] When the gas water heater of this application is running, the baffle cover 32 moves upward with the flue gas, opening the downstream opening of the connecting cylinder 2, allowing the flue gas to flow into the connecting cylinder 2 through the through hole 33. Simultaneously, the baffle cover 32 contacts the fixing frame 4, and the controller energizes the electromagnet 8 on the fixing frame 4, magnetically attaching the baffle cover 32 to the fixing frame 4. Because the baffle cover 32 is firmly magnetically fixed to the fixing frame 4, it will not vibrate significantly with the flow of flue gas, thus reducing the overall noise of the gas water heater. When the gas water heater stops running, the controller de-energizes the electromagnet 8. Since the baffle cylinder 31 is movably inserted into the connecting cylinder 2, the baffle cover 32 can fall down under gravity, re-closing the upstream opening of the connecting cylinder 2, closing the flue gas passage, and preventing backdraft. Since the windshield cover 32 is connected to the windshield cylinder 31, compared with the conventional hinged anti-backdraft windshield cover 32, the windshield cover 32 and the windshield cylinder 31 are heavier as a whole, and the pressure of closing is greater. In addition, the windshield cylinder 31 is fitted with the connecting cylinder 2 in a plug-in manner, so it is not easy for the windshield cover 32 to be blown open by the turbulence caused by backdraft, thus the sealing performance is better.

[0071] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A backdraft prevention mechanism for a gas-fired water heater, characterized in that, include: Chimney (1); A connecting cylinder (2) is located at least partially inside the chimney (1), and the connecting cylinder (2) is sealed to the chimney (1); The windshield assembly (3) includes a windshield cylinder (31) and a windshield cover (32) connected to each other. The windshield cylinder (31) is movably inserted into the connecting cylinder (2). The windshield cover (32) is located at the end of the windshield cylinder (31) away from the connecting cylinder (2) and is used to cover the downstream opening of the connecting cylinder (2). A through hole (33) is provided on the side wall of the windshield cylinder (31), and the windshield cover (32) has a magnetic suction part (322). A fixing frame (4) is provided inside the chimney (1); along the flow direction of the flue gas, the fixing frame (4) is located downstream of the windshield cover (32); An electromagnet (8) is mounted on the fixed frame (4); A controller, which is electrically connected to the electromagnet (8); When the windshield cover (32) moves upward and opens the downstream opening as the gas water heater operates, the windshield cover (32) contacts the fixing frame (4), the controller controls the electromagnet (8) to be energized to attract and fix the magnetic suction part (322), and the through hole (33) is connected to the inner cavity of the chimney (1).

2. The anti-backdraft mechanism according to claim 1, characterized in that, The windshield (32) is at least partially made of a ferromagnetic material or a permanent magnet to form the magnetic attraction part (322).

3. The anti-backdraft mechanism according to claim 2, characterized in that, It also includes a sealing ring (5), which is sleeved and fixed to the connecting cylinder (2), and the connecting cylinder (2) is sealed to the chimney (1) through the sealing ring (5).

4. The anti-backdraft mechanism according to claim 3, characterized in that, The sealing ring (5) includes: The bottom wall of the windshield cover (32) is provided with a first annular inclined surface (321), and the top of the connecting cylinder (2) is provided with an outwardly expanding second annular inclined surface (21). The first annular inclined surface (321) and the second annular inclined surface (21) abut and fit together.

5. The anti-backdraft mechanism according to any one of claims 1 to 4, characterized in that, The fixing frame (4) includes: Support plate (41), the electromagnet (8) is fixed on the support plate (41); Multiple connecting strips (43) are provided, one end of which is connected to the support plate (41), and the other end of which is connected to the inner wall of the chimney (1).

6. The anti-backdraft mechanism according to claim 5, characterized in that, The multiple connecting strips (43) are evenly and radially distributed around the support plate (41).

7. The anti-backdraft mechanism according to claim 6, characterized in that, A fixed shell (42) is provided on the support plate (41), and the electromagnet (8) is installed inside the fixed shell (42).

8. The anti-backdraft mechanism according to claim 7, characterized in that, The fixing frame (4) also includes: A reinforcing rib is provided on the connecting strip (43) and extends along the length direction of the connecting strip (43).

9. The anti-backdraft mechanism according to claim 7 or 8, characterized in that, The support plate (41) is provided with a contact convex surface (411), and the electromagnet (8) is provided on the back side of the contact convex surface (411). When the windproof cover (32) is opened, the magnetic suction part (322) abuts against the contact convex surface (411).

10. A gas-fired hot water device, characterized in that, include: The exhaust pipe and the anti-backdraft mechanism as described in any one of claims 1 to 9, wherein the exhaust pipe is connected to the chimney (1) of the anti-backdraft mechanism.

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