Downdraft prevention mechanism

Abstract

The utility model relates to the technical field of gas water heating equipment, in particular to an anti-downdraft mechanism, which comprises a chimney, an air inlet pipe and an air outlet pipe, the air blocking piece is arranged in the smoke pipe and hinged to the smoke pipe; a magnetic attraction part is arranged on the air blocking sheet; the first electromagnet is arranged in the chimney; the second electromagnet is arranged in the chimney; when the gas water heating equipment is in a running state, the air blocking piece is opened and connected with the first electromagnet in a magnetic attraction mode, and when the gas water heating equipment stops running, the air blocking piece is closed and connected with the second electromagnet in a magnetic attraction mode. When the gas water heating equipment is used, the fan is started, the first electromagnet can fix the air blocking piece, it is guaranteed that the position of the air blocking piece is stable, and therefore the situation that the air blocking piece is driven to shake when smoke flows can be prevented. After the gas water heating equipment is used, the second electromagnet fixes the air blocking piece, and therefore sealing of the smoke exhaust pipeline is guaranteed.

Description

Technical Field

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

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

[0003] To prevent backdraft, an anti-backdraft mechanism is typically installed in the exhaust duct. When these gas-fired water heaters are operating, the anti-backdraft mechanism opens the exhaust duct under the influence of flue gas, ensuring that exhaust gases can be normally discharged outdoors. When the gas-fired water heaters stop operating, the anti-backdraft mechanism closes the exhaust duct under its own weight, preventing cold outdoor air from flowing back into the gas-fired water heaters.

[0004] However, existing anti-backdraft mechanisms vibrate with the flow of flue gas, affecting not only the stability of the mechanism itself but also transmitting the vibration to adjacent components, generating significant noise. Furthermore, when the gas water heater stops operating, if the outdoor airflow velocity is high, the anti-backdraft mechanism may automatically open the exhaust pipe due to air pressure, allowing cold air to flow back into the gas water heater, resulting in a leak. Utility Model Content

[0005] In view of this, the present invention provides an anti-backdraft mechanism to solve the problems of noise generation and poor sealing of the anti-backdraft mechanism.

[0006] In a first aspect, this utility model provides an anti-backdraft mechanism for use in gas-fired water heaters, the anti-backdraft mechanism comprising:

[0007] Chimney, with a smoke inlet;

[0008] A wind deflector is disposed in the chimney and hinged to the chimney. The wind deflector has a magnetic attraction part and is used to open or cover the smoke outlet.

[0009] A first electromagnet is installed in the chimney;

[0010] A second electromagnet is installed in the chimney;

[0011] The controller is electrically connected to the first electromagnet and the second electromagnet respectively;

[0012] When the wind deflector opens the flue gas outlet as the gas-fired water heater operates, the controller controls the first electromagnet to be energized to attract and fix the magnetic suction part.

[0013] When the gas-fired water heater stops running, the controller controls the first electromagnet to be de-energized or energized in reverse so that the magnetic part is detached from the first electromagnet and the wind deflector covers the flue gas outlet. The controller then controls the second electromagnet to be energized to attract and fix the magnetic part.

[0014] Beneficial effects: In this embodiment of the invention, when using the gas-fired water heater, the fan starts and energizes the first electromagnet. The airflow generated by the fan blows open the baffle plate, which is then attracted to the first electromagnet. The first electromagnet can fix the baffle plate in place, ensuring its stable position and preventing it from shaking due to flue gas flow. When the gas-fired water heater is shut down, the first electromagnet is de-energized and the second electromagnet is energized. The fan stops working, and the baffle plate falls under gravity and is attracted to the second electromagnet, fixing it in place. This prevents the baffle plate from opening the exhaust pipe due to air pressure, thus ensuring the exhaust pipe is sealed and preventing cold outdoor air from flowing back into the gas-fired water heater.

[0015] In one alternative embodiment, the wind deflector is at least partially made of a ferromagnetic material or a permanent magnet, forming the magnetic attraction portion.

[0016] Beneficial effects: The wind deflector in this embodiment is made of ferromagnetic material or permanent magnet, with a simple structure. It can be controlled to keep the wind deflector open and closed by the electromagnetic force generated by the first electromagnet and the second electromagnet. There is no need to set other parts in the chimney to connect the wind deflector. It is simple and effective. There is no need to worry about other parts used to connect the wind deflector being corroded by long-term exhaust gas emission. It ensures that the first electromagnet and the second electromagnet can operate normally.

[0017] In one optional embodiment, the chimney includes: a chimney body, an annular fixing platform, and a connecting cylinder. The fixing platform is disposed in the inner cavity of the chimney body, the connecting cylinder passes through an opening fixed to the fixing platform, the flue gas outlet is disposed in the connecting cylinder, the second electromagnet is fixed to the fixing platform, and the connecting cylinder is used to connect to the exhaust pipe of the gas water heater.

[0018] In one optional embodiment, a support member is further included, which is disposed on the inner side wall of the chimney. The first electromagnet is fixed to one end face of the support member. When the wind deflector opens the smoke outlet, the free end of the wind deflector is in contact with the other end face of the support member.

[0019] In one optional embodiment, the support member includes a connecting plate and a bending plate integrally bent, the connecting plate being fixedly connected to the inner sidewall of the chimney, and the first electromagnet being fixed to the bending plate.

[0020] In one alternative embodiment, a reinforcing rib is provided between the connecting plate and the bending plate.

[0021] Beneficial effects: By setting reinforcing ribs, the overall structure of the support can be further strengthened, so that the support can be stably attached to the inner wall of the chimney, preventing the support from bending under the strong magnetic force of the first electromagnet, thereby ensuring the normal operation of the anti-backdraft structure.

[0022] In one optional embodiment, the bending plate is further provided with a first fixing shell, the first electromagnet is installed and fixed in the first fixing shell, the connecting plate and the fixing platform are both provided with a first wiring hole that communicates with each other, and the connecting wire of the first electromagnet is led out of the chimney body through the first wiring hole.

[0023] In one optional embodiment, the fixed platform is further provided with a hinge seat, and the wind baffle is hinged to the chimney through the hinge seat. The hinge seat is provided with a clearance hole that communicates with the first wiring hole of the fixed platform.

[0024] In one optional embodiment, the bottom wall of the wind deflector 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, the first annular inclined surface and the second annular inclined surface abutting and fitting together.

[0025] In one optional embodiment, a second fixing shell is provided on the fixing platform, the second electromagnet is installed on the second fixing shell, and the fixing platform and the second fixing shell are respectively provided with a second wiring hole that communicates with each other. The connecting wire of the second electromagnet is led out of the chimney body through the second wiring hole. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is an exploded view of an anti-backdraft mechanism according to an embodiment of the present utility model;

[0028] Figure 2This is a schematic diagram of the wind deflector in the open state in an embodiment of the present invention;

[0029] Figure 3 This is a cross-sectional view of the windshield in the open state in an embodiment of this utility model;

[0030] Figure 4 for Figure 3 An enlarged schematic diagram of part A in the middle;

[0031] Figure 5 This is a schematic diagram of the windshield in the closed state in an embodiment of the present invention;

[0032] Figure 6 This is a cross-sectional view of the windshield in the closed state in an embodiment of this utility model;

[0033] Figure 7 for Figure 6 Enlarged schematic diagram of part B.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Chimney body; 21. Fixing platform; 22. Smoke outlet; 23. Wind baffle; 231. Magnetic suction part; 232. First annular inclined surface; 24. Hinge seat; 25. Connecting cylinder; 251. Second annular inclined surface; 26. Receiver base; 27. Receiver; 28. Second fixing shell; 3. First electromagnet; 4. Support member; 41. Connecting plate; 42. Bending plate; 5. First fixing shell; 6. Reinforcing rib; 7. Second electromagnet; 8. First wiring hole; 9. Clearance hole; 10. Second wiring hole. Detailed Implementation

[0036] 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.

[0037] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0038] 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, a wind deflector 23, a first electromagnet 3, and a second electromagnet 7.

[0039] Specifically, in the embodiments of this utility model, such as Figure 1As shown, the chimney has a flue outlet 22. The chimney is suitable for connection to the exhaust pipe of a gas-fired water heater. The exhaust pipe is used to discharge exhaust gas. The chimney can be connected to the exhaust pipe or it can be part of the exhaust pipe itself. When the chimney is connected to the exhaust pipe, the chimney can be directly fitted onto the exhaust pipe, or the chimney and the exhaust pipe can be directly welded together by covering them with sheet metal.

[0040] Of course, this embodiment is merely an example of the connection method between the chimney 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.

[0041] Furthermore, in this embodiment of the present invention, a wind deflector 23 is disposed in the chimney and hinged to the chimney, the wind deflector 23 has a magnetic suction part 231, and the wind deflector 23 is used to open or cover the smoke outlet 22.

[0042] Furthermore, in this embodiment of the invention, the first electromagnet 3 is disposed in the chimney. When the gas-fired water heater is in use, the fan starts, the baffle 23 opens, and the first electromagnet 3 is energized. Under the magnetic force of the first electromagnet 3, the baffle 23 is magnetically connected to the first electromagnet 3, keeping the baffle 23 in the open state.

[0043] Furthermore, in this embodiment of the invention, the second electromagnet 7 is disposed in the chimney. When the baffle 23 is closed, the gas-fired water heater is no longer in use. After the gas-fired water heater has been used, the fan stops working, and the baffle 23 is closed. At this time, the second electromagnet 7 is activated, and under the magnetic force of the second electromagnet 7, the baffle 23 is magnetically connected to the second electromagnet 7, keeping the baffle 23 in a closed state.

[0044] Furthermore, in this embodiment of the invention, the controller is electrically connected to the first electromagnet 3 and the second electromagnet 7, respectively. When the wind deflector 23 opens the flue gas outlet 22 during operation of the gas-fired water heater, the controller controls the first electromagnet 3 to be energized to attract and fix the magnetic suction part 231. When the gas-fired water heater stops operating, the controller controls the first electromagnet 3 to be de-energized or energized in reverse to cause the magnetic suction part 231 to detach from the attraction of the first electromagnet 3 and to cause the wind deflector 23 to cover the flue gas outlet 22. The controller then controls the second electromagnet 7 to be energized to attract and fix the magnetic suction part 231.

[0045] With this configuration, in this embodiment of the invention, when the gas-fired water heater is in use, the fan starts, the baffle 23 opens, and the first electromagnet 3 is energized. After the airflow generated by the fan blows open the baffle 23, the first electromagnet 3 attracts the baffle 23, thus fixing it in place and ensuring its stable position. This prevents the baffle 23 from shaking due to the flow of flue gas. When the gas-fired water heater is shut down, the first electromagnet 3 is de-energized, the second electromagnet 7 is energized, the fan stops working, and the baffle 23 falls under gravity. The second electromagnet 7 attracts and fixes the baffle 23, preventing it from opening the exhaust pipe due to air pressure. This ensures the exhaust pipe is sealed, preventing cold outdoor air from flowing back into the gas-fired water heater.

[0046] Furthermore, in an alternative implementation, such as Figures 1 to 3 , Figure 5 , Figure 6 As shown, at least a portion of the wind deflector 23 is a ferromagnetic component or a permanent magnet, forming the magnetic attraction part 231. Specifically, the permanent magnet is a common neodymium magnet, AlNiCo magnet, or ferrite magnet, etc., all of which are permanent magnets with inherent magnetism; the ferromagnetic component is made of common materials such as iron, cobalt, nickel, or cobalt-iron alloy, etc., all of which are ferromagnetic components that are not magnetic themselves but can be attracted by a magnet.

[0047] In actual operation, the end of the wind deflector 23 furthest from the hinge position is the free end. When the first electromagnet 3 is energized, it attracts the free end of the wind deflector 23, keeping it open. When the second electromagnet 7 is energized, it attracts the free end of the wind deflector 23, keeping it closed.

[0048] With this configuration, the wind deflector 23 in this embodiment of the present invention is made of ferromagnetic material or permanent magnet, which has a simple structure. The wind deflector 23 can be kept open and closed by the electromagnetic force generated by the first electromagnet 3 and the second electromagnet 7. There is no need to set other parts in the chimney to connect the wind deflector 23. It is simple and effective, and there is no need to worry about other parts used to connect the wind deflector 23 being corroded by long-term exhaust gas emissions. This ensures that the first electromagnet 3 and the second electromagnet 7 can operate normally.

[0049] This embodiment of the invention provides a magnetic attraction part 231 at the free end of the windshield 23, and also provides the magnetic attraction part 231 on the first electromagnet 3 and the second electromagnet 7. Under the action of magnetic attraction, the windshield 23 automatically moves towards the first electromagnet 3 or the second electromagnet 7, thereby making the magnetic attraction part 231 fit together and increasing the area of ​​magnetic attraction. Furthermore, compared to direct contact with the windshield 23, the cooperation between the magnetic attraction parts 231 and 231 is more stable, ensuring that the position of the windshield 23 is fixed.

[0050] Of course, the magnetic attraction part 231 can also be provided only on the first electromagnet 3 or the second electromagnet 7. This embodiment is just an example, but it is not a limitation. As long as the same technical effect can be achieved, it is acceptable.

[0051] Furthermore, in an alternative implementation, such as Figures 3 to 5 As shown, the chimney includes: a chimney body 1, an annular fixing platform 21, and a connecting cylinder 25. The fixing platform 21 is located inside the chimney body 1. The connecting cylinder 25 passes through an opening fixed to the fixing platform 21. The flue gas outlet 22 is located on the connecting cylinder 25. The second electromagnet 7 is fixed to the fixing platform 21. The connecting cylinder 25 is used to connect to the exhaust pipe of the gas water heater.

[0052] Specifically, in this embodiment of the invention, the fixing platform 21 has a smoke outlet 22. The fixing platform 21 is disposed in the chimney body 1, and the edge of the fixing platform 21 is tightly fitted with the inner wall of the chimney body 1. The edge of the fixing platform 21 can be spot welded to the inner wall of the chimney body 1, so that the edge of the fixing platform 21 and the inner wall of the chimney body 1 are in a sealed state. Of course, a sealing ring can also be provided at the edge of the fixing platform 21, and then the sealing ring can be used to seal the edge of the fixing platform 21 and the inner wall of the chimney body 1.

[0053] Furthermore, the wind deflector 23 is rotatably mounted on the fixed platform 21. The wind deflector 23 has a first position where the smoke outlet 22 is open, and in the first position, the wind deflector 23 is magnetically connected to the first electromagnet 3. The wind deflector 23 has a second position where it covers the smoke outlet 22, and in the second position, the wind deflector 23 is magnetically connected to the second electromagnet 7.

[0054] Specifically, in the first position, after the first electromagnet 3 is activated, the wind deflector 23 is magnetically connected to the first electromagnet 3, thereby keeping the smoke outlet 22 open and conducting the smoke cylinder body 1. In the second position, after the second electromagnet 7 is activated, the wind deflector 23 is magnetically connected to the second electromagnet 7, thereby keeping it covering the smoke outlet 22 and closing the smoke cylinder body 1.

[0055] Furthermore, the connecting cylinder 25 is inserted into the smoke outlet 22 and sealed to the fixed platform 21. The wind deflector 23, when rotated, has a first position where the connecting cylinder 25 is open and a second position where the connecting cylinder 25 is covered. The connecting cylinder 25 and the chimney body 1 can be connected by spot welding.

[0056] Furthermore, in an alternative implementation, such as Figure 3 and Figure 4 As shown, the support member 4 is disposed on the inner side wall of the chimney, the first electromagnet 3 is fixed to one end face of the support member 4, and when the wind deflector 23 opens the smoke outlet 22, the free end of the wind deflector 23 is in contact with the other end face of the support member 4.

[0057] Specifically, the support member 4 is disposed in the inner cavity of the chimney body 1, with one end of the support member 4 fitting against and fixed to the inner wall of the chimney body 1. The first electromagnet 33 is fixed on the support member 4, with its magnetic pole facing the wall surface of the support member 4. When the wind deflector 23 is opened, the free end of the wind deflector 23 fits against the wall surface of the support member 4.

[0058] With this configuration, the support member 4 in this embodiment of the invention provides an installation position for the first electromagnet 33, thereby facilitating its installation and simplifying the installation process. Furthermore, compared to directly fixing the first electromagnet 33 inside the chimney body 1, the cooperation between the support member 4 and the first fixing shell 5 makes the first electromagnet 33 more stable.

[0059] Furthermore, the support member 4 and the chimney body 1 can be either fixedly connected or detachably connected. For a fixed connection, welding, bonding, or other methods can be used. For a detachable connection, screws and screw holes, clips and slots, or magnetic attraction can be used for fixation.

[0060] The following provides examples of detachable connection methods. For instance, a fixing plate can be additionally provided on the support member 4. Those skilled in the art can change the number of fixing plates according to actual conditions, such as 1, 2, 3, 4, etc. Screw holes are then made on the fixing plates. On the chimney body 1, another screw hole is made at the corresponding screw hole position. Screws are then passed through the screw holes on the fixing plate and the chimney body 1 in sequence, thereby connecting the chimney body 1 to the support member 4. Furthermore, when using a snap-fit ​​and slot method for fixing, snap-fits can be additionally provided on the chimney body 1. Those skilled in the art can change the number of snap-fits according to actual conditions, such as 1, 2, 3, 4, etc. Slots that can cooperate with the snap-fits are then made on the support member 4 at the corresponding snap-fit ​​positions. The snap-fits on the chimney body 1 are then directly embedded into the slots on the support member 4, thereby connecting the chimney body 1 to the support member 4.

[0061] Of course, this embodiment is merely an example of fixed connection and detachable connection, but it does not limit the scope of the invention. Those skilled in the art can make changes according to the actual situation to achieve the same technical effect.

[0062] Furthermore, in an alternative implementation, such as Figure 4 As shown, the support member 4 includes a connecting plate 41 and a bent plate 42 formed by integral bending. The connecting plate 41 is fixedly connected to the inner wall of the chimney, and the first electromagnet 3 is fixed to the bent plate 42. A reinforcing rib 6 is provided between the connecting plate 41 and the bent plate 42.

[0063] The number and location of the reinforcing ribs 6 can be modified by those skilled in the art according to actual conditions. The reinforcing ribs 6 can be located on both sides of the support member 4, so that they together with the support member 4 and the inner wall of the chimney body 1 form an installation cavity. Of course, this embodiment is only 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.

[0064] With this configuration, the present invention can further strengthen the overall structure of the support member 4 by setting the reinforcing rib 6, so that the support member 4 can be stably attached to the inner wall of the chimney body 1, preventing the support member 4 from bending under the strong magnetic force of the first electromagnet 33, thereby ensuring the normal operation of the anti-backdraft structure.

[0065] Furthermore, in an optional embodiment, the bending plate 42 is also provided with a first fixing shell 5, the first electromagnet 3 is installed and fixed inside the first fixing shell 5, the connecting plate 41 and the fixing platform 21 are both provided with interconnected first wiring holes 8, and the connecting wire of the first electromagnet 3 is led out of the chimney body 1 through the first wiring hole 8.

[0066] Specifically, the first fixing shell 5 has a cylindrical structure. The first fixing shell 5 can be welded to the bending plate 42 to ensure structural stability. The first electromagnet 33 is disposed in the first fixing shell 5, and the first electromagnet 33 and the first fixing shell 5 can be glued together or fixed with screws.

[0067] Furthermore, in an alternative implementation, such as Figure 1 , Figure 3 , Figure 6 As shown, the fixed platform 21 is also provided with a hinge seat 24, and the wind baffle 23 is hinged to the chimney through the hinge seat 24. The hinge seat 24 is provided with a clearance hole 9 that communicates with the first wiring hole 8 of the fixed platform 21.

[0068] Specifically, in this embodiment of the invention, the hinge seat 24 is disposed on the fixed platform 21, and the hinge seat 24 is rotatably connected to the wind deflector 23 via a pin. The pin ensures the accuracy and reliability of the connection. The hinge seat 24 and the fixed platform 21 can also be connected by spot welding; of course, other methods can also be used to achieve fixation.

[0069] Furthermore, in an alternative implementation, such as Figure 1 As shown, the anti-backdraft mechanism also includes a receiving cylinder base 26 and a receiving cylinder 27. Along the exhaust direction, the receiving cylinder base 26 and the receiving cylinder 27 are located at the downstream port of the chimney body 1. The receiving cylinder base 26 is spot-welded to the chimney body 1, and the receiving cylinder 27 can also be spot-welded to the receiving cylinder base 26.

[0070] Furthermore, in an alternative implementation, such as Figure 6 and Figure 7 As shown, the bottom wall of the wind deflector 23 is provided with a first annular inclined surface 232, and the top of the connecting cylinder 25 is provided with an outwardly expanding second annular inclined surface 251. The first annular inclined surface 232 and the second annular inclined surface 251 abut against each other.

[0071] Specifically, in this embodiment, a first annular inclined surface 232 is disposed on the end face of the wind deflector 23 near the connecting cylinder 25, and the first annular inclined surface 232 protrudes in the direction close to the connecting cylinder 25. A second annular inclined surface 251 is disposed on the top edge of the connecting cylinder 25, and the second annular inclined surface 251 expands outward along the radial direction of the connecting cylinder 25. When the wind deflector 23 covers the connecting cylinder 25, the first annular inclined surface 232 abuts against the second annular inclined surface 251.

[0072] In other words, the wind deflector 23 is pressed into a downward convex shape, and the top end of the connecting cylinder 25 is made into a second annular inclined surface 251 shape. When the wind deflector 23 is fastened onto the connecting cylinder 25, the downward convex shape can just fit onto the second annular inclined surface 251, thereby making the wind deflector 23 and the connecting cylinder 25 fit more tightly.

[0073] Furthermore, in an alternative implementation, such as Figure 6 As shown, a second fixed shell 28 is provided on the fixed platform 21, and the second electromagnet 7 is installed on the second fixed shell 28. The fixed platform 21 and the second fixed shell 28 are respectively provided with a second wiring hole 10 that communicates with each other. The connecting wire of the second electromagnet 7 is led out of the chimney body 1 through the second wiring hole 10.

[0074] like Figure 3 and Figure 6 As shown, the first electromagnet 3 is disposed on the inner wall of the chimney body 1 and is located above the second electromagnet 7 on the opposite side.

[0075] 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 with a smoke inlet (22); A wind deflector (23) is disposed in the chimney and hinged to the chimney. The wind deflector (23) has a magnetic suction part (231). The wind deflector (23) is used to open or cover the smoke outlet (22). A first electromagnet (3) is installed in the chimney; A second electromagnet (7) is installed in the chimney; The controller is electrically connected to the first electromagnet (3) and the second electromagnet (7) respectively; When the wind deflector (23) opens the flue (22) as the gas water heater is running, the controller controls the first electromagnet (3) to be energized to attract and fix the magnetic suction part (231); When the gas-fired water heater stops running, the controller controls the first electromagnet (3) to be de-energized or energized in reverse so that the magnetic part (231) is detached from the first electromagnet (3) and the wind deflector (23) covers the smoke outlet (22). The controller controls the second electromagnet (7) to be energized to attract and fix the magnetic part (231).

2. The anti-backdraft mechanism according to claim 1, characterized in that, The wind deflector (23) is at least partially made of a ferromagnetic material or a permanent magnet, forming the magnetic attraction part (231).

3. The anti-backdraft mechanism according to claim 1, characterized in that, The chimney includes: a chimney body (1), an annular fixed platform (21) and a connecting tube (25). The fixed platform (21) is located in the inner cavity of the chimney body (1). The connecting tube (25) passes through an opening fixed to the fixed platform (21). The smoke outlet (22) is located on the connecting tube (25). The second electromagnet (7) is fixed to the fixed platform (21). The connecting tube (25) is used to connect to the exhaust pipe of the gas water heater.

4. The anti-backdraft mechanism according to claim 3, characterized in that, It also includes a support member (4), which is disposed on the inner side wall of the chimney. The first electromagnet (3) is fixed to one end face of the support member (4). When the wind deflector (23) opens the smoke outlet (22), the free end of the wind deflector (23) is in contact with the other end face of the support member (4).

5. The anti-backdraft mechanism according to claim 4, characterized in that, The support member (4) includes a connecting plate (41) and a bending plate (42) formed by integral bending. The connecting plate (41) is fixedly connected to the inner wall of the chimney, and the first electromagnet (3) is fixed to the bending plate (42).

6. The anti-backdraft mechanism according to claim 5, characterized in that, A reinforcing rib (6) is provided between the connecting plate (41) and the bending plate (42).

7. The anti-backdraft mechanism according to claim 5, characterized in that, The bending plate (42) is also provided with a first fixing shell (5), and the first electromagnet (3) is installed and fixed inside the first fixing shell (5). The connecting plate (41) and the fixing platform (21) are both provided with a first wiring hole (8) that is interconnected. The connecting wire of the first electromagnet (3) is led out of the chimney body (1) through the first wiring hole (8).

8. The anti-backdraft mechanism according to claim 7, characterized in that, The fixed platform (21) is also provided with a hinge seat (24), and the wind baffle (23) is hinged to the chimney through the hinge seat (24). The hinge seat (24) is provided with a clearance hole (9) that communicates with the first wiring hole (8) of the fixed platform (21).

9. The anti-backdraft mechanism according to claim 3, characterized in that, The bottom wall of the wind deflector (23) is provided with a first annular inclined surface (232), and the top of the connecting cylinder (25) is provided with an outwardly expanding second annular inclined surface (251). The first annular inclined surface (232) and the second annular inclined surface (251) abut and fit together.

10. The anti-backdraft mechanism according to claim 3, characterized in that, The fixed platform (21) is provided with a second fixed shell (28), and the second electromagnet (7) is installed in the second fixed shell (28). The fixed platform (21) and the second fixed shell (28) are respectively provided with a second wiring hole (10) that communicates with each other. The connecting wire of the second electromagnet (7) is led out of the chimney body (1) through the second wiring hole (10).

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