Gas water heating equipment
By designing a dual anti-wind air device in the gas water heater equipment, the problem of existing gas water heaters being prone to freezing in cold weather is solved, and stronger anti-freeze performance and equipment reliability are achieved.
Patent Information
- Application Number
- CN202421164983.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-05-27
AI Technical Summary
The existing gas water heater can easily cause the water tank to freeze in cold weather, and the existing anti-wind joints have insufficient sealing force, which cannot effectively prevent cold air from invading.
Design a gas-fired water-fired device, adopting a double anti-wind air device, the first anti-wind air device and the second anti-wind air device are installed along the extension direction of the smoke pipe, and the second anti-wind air device is located close to the first anti-wind air device One side of the hot water body is spaced from the first anti-inverting device by more than 300 mm.
The dual anti-wind air function is realized to ensure that cold air cannot enter the hot water body, prevent the water tank from freezing, and heat the cold air in the smoke pipe through indoor warm air, further improving the anti-freezing performance of the equipment.
Smart Images
Figure CN222480782U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of gas water heaters, in particular to a gas water heater. Background Art
[0002] In the existing anti-freeze function of gas water heaters, an anti-backflow joint is generally used to prevent the invasion of cold air. In order to ensure the sealing, a sealing rubber ring is generally installed at the interface of the anti-backflow joint for sealing. When the gas water heater is on standby and not started, the anti-backflow bracket is covered on the sealing rubber ring by gravity. When the gas water heater is started, the fan starts and the wind blows open the anti-backflow bracket to open the flue gas discharge channel. Since the anti-backflow joint is sealed by the gravity of the anti-backflow bracket, and the anti-backflow bracket is only made of 0.3mm-0.8mm thick stainless steel metal, the sealing force is generally small. In cold weather with fluctuating outdoor winds, if the anti-backflow joint is not tightly sealed, the water tank of the water heater will still be frozen. Utility Model Content
[0003] The technical problem solved by the present application is to provide a gas water heater which has a dual anti-backdraft function and can utilize the warm air in the room to heat and insulate the cold air in the smoke pipe, thereby ensuring that the water tank in the gas water heater will not be frozen.
[0004] The above technical problems are solved by the following technical solutions:
[0005] A gas water heater, comprising:
[0006] Hot water body;
[0007] A smoke pipe, the smoke pipe is connected to the hot water body;
[0008] A first backdraft prevention device, wherein the first backdraft prevention device is installed on the smoke pipe; and
[0009] The second anti-backdraft device is installed on the smoke pipe. Along the extension direction of the smoke pipe, the second anti-backdraft device is located on the side of the first anti-backdraft device close to the hot water body and is spaced more than 300 mm from the first anti-backdraft device.
[0010] The gas water heater of the present application has the following beneficial effects compared with the background technology:
[0011] When the gas water heater in the above embodiment is used, the water heater body is installed indoors, and the smoke pipe is installed in the wall, so that the smoke generated during the operation of the water heater body can be discharged to the outside through the smoke pipe, and the first anti-backwind device and the second anti-backwind device on the smoke pipe are both located indoors. Compared with the existing gas water heater, the present application has the first anti-backwind device and the second anti-backwind device, and the gas water heater has a dual anti-backwind function. When cold air leaks at the first anti-backwind device, the second anti-backwind device can still block the cold air, ensuring that the cold air will not enter the interior of the water heater body through the smoke pipe, overcoming the problem that the water tank in the water heater body will be frozen, and improving the reliability of the gas water heater. In addition, after the cold air passes through the first anti-backdraft device, since there is a distance of more than 300 mm between the first anti-backdraft device and the second anti-backdraft device along the extension direction of the smoke pipe, and the first anti-backdraft device and the second anti-backdraft device are both located indoors, in the process of the cold air flowing from the first anti-backdraft device to the second anti-backdraft device, the indoor warm air can heat and insulate the cold air in the smoke pipe through the smoke pipe, ensuring that no low-temperature air enters the interior of the hot water body, ensuring that the water tank in the hot water body will not be frozen, and improving the reliability of the gas water heater.
[0012] The technical solution is further described below:
[0013] In one of the embodiments, along the extension direction of the smoke pipe, the second backdraft prevention device is spaced 500 mm from the first backdraft prevention device.
[0014] In one embodiment, the smoke pipe includes a first pipe section for connecting to the external environment, and a second pipe section for connecting to the hot water body, the axis of the first pipe section and the axis of the second pipe section are set at an angle, the first backdraft prevention device is installed on the first pipe section, and the second backdraft prevention device is installed on the second pipe section.
[0015] In one embodiment, the first pipe section extends in a horizontal direction, and the second pipe section extends in a vertical direction.
[0016] In one embodiment, the second anti-backdraft device is located outside the hot water body; or, the second anti-backdraft device is located inside the hot water body.
[0017] In one embodiment, the first anti-backflow device includes a mounting body and an anti-backflow piece, the mounting body is provided with a mounting cavity, and a smoke inlet and a smoke outlet both connected to the mounting cavity, the smoke pipe includes a first pipe section, the first pipe section includes a smoke inlet pipe and a smoke outlet pipe arranged at intervals, the smoke inlet pipe extends into the mounting cavity through the smoke inlet, the smoke outlet is installed at the smoke outlet, and is used to connect the mounting cavity with the external environment, the anti-backflow piece is rotatably arranged in the mounting cavity, when the smoke pipe is in a non-smoke exhaust state, the anti-backflow piece is covered on the smoke outlet end of the smoke inlet pipe under the action of gravity to separate the smoke inlet pipe from the mounting cavity, and when the smoke pipe is in a smoke exhaust state, the anti-backflow piece rotates away from the smoke outlet end under the action of smoke to connect the smoke inlet pipe with the mounting cavity.
[0018] In one of the embodiments, the first backflow prevention device further includes a counterweight component, and the counterweight component is installed on the backflow prevention component.
[0019] In one embodiment, the first backflow prevention device also includes a connecting piece, which is installed on the top of the installation cavity and located above the smoke outlet end, one side of the backflow prevention piece is rotatably connected to the connecting piece, and the counterweight piece is installed on a side of the backflow prevention piece away from the connecting piece.
[0020] In one of the embodiments, the backflow prevention member is recessed toward a side away from the smoke outlet end to form a groove, and the inner diameter of the groove is larger than the outer diameter of the end face of the smoke outlet end. When the smoke pipe is in a non-smoke exhaust state, the backflow prevention member is inverted on the smoke outlet end under the action of gravity to separate the smoke inlet pipe from the installation cavity.
[0021] In one embodiment, the first backflow prevention device further includes a limiting member, which is installed at the top of the installation cavity and is located between the smoke inlet pipe and the smoke outlet pipe, and the limiting member is used to limit the rotation angle of the backflow prevention member relative to the smoke inlet pipe. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0024] FIG. 1 is a schematic structural diagram of a gas water heater according to an embodiment.
[0025] FIG. 2 is a schematic structural diagram of a gas water heater according to another embodiment.
[0026] FIG. 3 is a schematic diagram of the structure of the gas water heater of FIG. 2 when in use.
[0027] FIG. 4 is a partial enlarged view of portion A in FIG. 2 .
[0028] Description of reference numerals:
[0029] 10. Gas water heater; 100. Smoke pipe; 110. First pipe section; 111. Smoke inlet pipe; 112. Smoke outlet pipe; 120. Second pipe section; 200. First backflow prevention device; 210. Installation body; 211. Installation cavity; 212. Smoke inlet; 213. Smoke outlet; 220. Backflow prevention member; 221. Groove; 222. Magnetic part; 230. Counterweight member; 240. Connecting member; 250. Limiting member; 260. Magnetic member; 300. Second backflow prevention device; 400. Water heater body; 500. Sealing rubber ring; 20. Wall. DETAILED DESCRIPTION
[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.
[0031] As shown in Fig. 1, Fig. 2 and Fig. 3, in one embodiment, a gas water heater 10 is provided, comprising a water heater body 400, a smoke pipe 100, a first backdraft prevention device 200 and a second backdraft prevention device 300. The smoke pipe 100 is connected to the water heater body 400. The first backdraft prevention device 200 is installed on the smoke pipe 100. The second backdraft prevention device 300 is installed on the smoke pipe 100. Along the extension direction of the smoke pipe 100, the second backdraft prevention device 300 is located on a side of the first backdraft prevention device 200 close to the water heater body 400, and is spaced more than 300 mm from the first backdraft prevention device 200.
[0032] When the gas water heater 10 in the above embodiment is used, the water heater body 400 is installed indoors, and the smoke pipe 100 is installed in the wall 20, so that the smoke generated during the operation of the water heater body 400 can be discharged to the outside through the smoke pipe 100, and the first anti-backdraft device 200 and the second anti-backdraft device 300 on the smoke pipe 100 are both located indoors. Compared with the existing gas water heater, the present application has the first anti-backdraft device 200 and the second anti-backdraft device 300, and the gas water heater 10 has a dual anti-backdraft function. When cold air leaks at the first anti-backdraft device 200, the second anti-backdraft device 300 can still play a role in blocking cold air, ensuring that cold air will not enter the interior of the water heater body 400 through the smoke pipe 100, overcoming the problem that the water tank in the water heater body 400 will be frozen, and improving the reliability of the gas water heater 10. In addition, after the cold air passes through the first anti-backdraft device 200, since there is a distance of more than 300 mm between the first anti-backdraft device 200 and the second anti-backdraft device 300 along the extension direction of the smoke pipe 100, and the first anti-backdraft device 200 and the second anti-backdraft device 300 are both located indoors, in the process of the cold air flowing from the first anti-backdraft device 200 to the second anti-backdraft device 300, the indoor warm air can heat and insulate the cold air in the smoke pipe 100 through the smoke pipe 100, ensuring that no low-temperature air (for example, air below 0 degrees) enters the interior of the hot water body 400, ensuring that the water tank in the hot water body 400 will not be frozen, thereby improving the reliability of the gas water heater 10.
[0033] The hot water body 400 can be set as any water heater structure in the prior art. The first anti-backdraft device 200 and the second anti-backdraft device 300 can both be set as any anti-backdraft structure in the prior art. The structure and working principle of the first anti-backdraft device 200 and the structure and working principle of the second anti-backdraft device 300 can be the same or different.
[0034] Among them, along the extension direction of the smoke pipe 100, the distance between the second anti-backwind device 300 and the first anti-backwind device 200 can be flexibly adjusted according to the actual use needs. Along the extension direction of the smoke pipe 100, the greater the distance between the second anti-backwind device 300 and the first anti-backwind device 200, the better the antifreeze performance of the gas water heater 10. The closer the first anti-backwind device 200 is to the wall 20, the better the antifreeze performance of the gas water heater 10. Specifically in this embodiment, along the extension direction of the smoke pipe 100, the second anti-backwind device 300 is 500mm away from the first anti-backwind device 200. In other embodiments, along the extension direction of the smoke pipe 100, the second anti-backwind device 300 is 300mm, 350mm, 400mm, 450mm, 550mm, 600mm or 650mm, etc.
[0035] As shown in Fig. 1 and Fig. 2, further, the smoke pipe 100 includes a first pipe section 110 for connecting to the external environment, and a second pipe section 120 for connecting to the hot water body 400, the axis of the first pipe section 110 and the axis of the second pipe section 120 are arranged at an angle, the first anti-backdraft device 200 is installed on the first pipe section 110, and the second anti-backdraft device 300 is installed on the second pipe section 120. In this way, the smoke pipe 100 is bent to effectively utilize the indoor space, so that the first anti-backdraft device 200 is close to the hot water body 400, and the second anti-backdraft device 300 is close to the wall 20, ensuring that the gas water heater 10 can effectively block cold air from entering the inside of the hot water body 400, thereby improving the reliability of the gas water heater 10.
[0036] The angle between the axis of the first pipe section 110 and the axis of the second pipe section 120 can be flexibly adjusted according to actual use requirements. Specifically in this embodiment, the first pipe section 110 extends in the horizontal direction, and the second pipe section 120 extends in the vertical direction.
[0037] The first anti-backdraft device 200 and / or the second anti-backdraft device 300 may be a split structure, or may be a finished product welded on the smoke pipe 100 , or may be built inside the hot water body 400 .
[0038] As shown in FIG. 1 , optionally, the second backdraft prevention device 300 is located inside the hot water body 400 .
[0039] As shown in FIG. 2 , optionally, the second backdraft prevention device 300 is located outside the water heater body 400. In this way, the second backdraft prevention device 300 can be installed outside or inside the water heater body 400 according to actual use needs, thereby improving the adaptability of the gas water heater 10.
[0040] In order to further understand the working principle of the gas water heater 10 in the present application, the application of the gas water heater 10 in the winter in the north is used as an example for explanation. The outdoor temperature in the north is lower than -20°C in winter, and northern families generally have indoor heating supply, and the indoor temperature is generally greater than 20°C. When the gas water heater 10 is not in operation, the temperature of each part of the gas water heater 10 is approximately as shown in FIG3.
[0041] As shown in FIG. 2 and FIG. 4, in one embodiment, the first backflow prevention device 200 includes a mounting body 210 and a backflow prevention member 220, the mounting body 210 is provided with a mounting cavity 211, and a smoke inlet 212 and a smoke outlet 213 both connected to the mounting cavity 211, the smoke pipe 100 includes a first pipe section 110, the first pipe section 110 includes a smoke inlet pipe 111 and a smoke outlet pipe 112 arranged at intervals, the smoke inlet pipe 111 extends into the mounting cavity 211 through the smoke inlet 212, and the smoke outlet pipe 112 is installed At the smoke outlet 213, and used to connect the installation cavity 211 and the external environment, the backflow prevention member 220 can be rotatably arranged in the installation cavity 211. When the smoke pipe 100 is in a non-smoke exhaust state, the backflow prevention member 220 is covered on the smoke outlet end of the smoke inlet pipe 111 under the action of gravity, so that the smoke inlet pipe 111 is separated from the installation cavity 211. When the smoke pipe 100 is in a smoke exhaust state, the backflow prevention member 220 rotates away from the smoke outlet end under the action of smoke, so that the smoke inlet pipe 111 is connected with the installation cavity 211. In this way, when the hot water body 400 is working, the smoke generated by the hot water body 400 is transported to the smoke pipe 100 to blow open the backflow prevention member 220, so that the hot water body 400, the second pipe section 120, the smoke inlet pipe 111, the installation cavity 211, the smoke outlet pipe 112 and the outdoor environment are connected in sequence for smoke exhaust. When the hot water body 400 stops working, the driving force of the smoke on the backflow prevention member 220 disappears, and the backflow prevention member 220 is covered on the smoke outlet under the action of gravity, so that the cold air in the outdoor environment cannot pass through the smoke outlet, thereby achieving the effect of preventing backflow.
[0042] Specifically in this embodiment, the backflow prevention member 220 can be set as a backflow prevention cover. The outer wall of the smoke inlet pipe 111 and the inner wall of the smoke inlet 212 are sealed together. The outer wall of the smoke outlet pipe 112 and the inner wall of the smoke outlet 213 are sealed together. The gas water heater 10 also includes a sealing rubber ring 500, which is installed at the smoke outlet end. When the smoke pipe 100 is in a non-smoke exhaust state, the backflow prevention cover is covered on the sealing rubber ring 500 under the action of gravity, so that the sealing rubber ring 500 can seal the inlet end and the backflow prevention cover.
[0043] As shown in Fig. 4, the first backflow prevention device 200 further includes a counterweight 230, which is mounted on the backflow prevention device 220. In this way, the counterweight 230 can increase the mass of the backflow prevention device 220, so that the gravity of the backflow prevention device 220 on the sealing rubber ring 500 is increased, and the sealing force between the smoke outlet and the backflow prevention device 220 is also increased, thereby improving the reliability of the first backflow prevention device 200.
[0044] As shown in Fig. 4, optionally, the first backflow prevention device 200 further includes a connecting member 240, which is installed at the top of the installation cavity 211 and is located above the smoke outlet end, one side of the backflow prevention member 220 is rotatably connected to the connecting member 240, and the counterweight 230 is installed on the side of the backflow prevention member 220 away from the connecting member 240. In this way, the distance between the counterweight 230 and the rotation axis of the backflow prevention member 220 is increased, so that the torque of the counterweight 230 is increased, ensuring that the counterweight 230 can press the backflow prevention member 220 against the smoke outlet end, thereby improving the reliability of the first backflow prevention device 200.
[0045] Specifically in this embodiment, the connecting member 240 can be configured as a connecting bracket, which can be fixed to the top of the inner wall of the installation cavity 211 by welding, screwing, plugging, clamping or other connection methods. The backflow prevention member 220 can be rotatably connected to the connecting bracket via a rotating shaft. The counterweight member 230 can be configured as a counterweight block, which is welded to the outer wall of the backflow prevention member 220.
[0046] As shown in FIG. 4 , in one embodiment, the backflow prevention member 220 is recessed toward the side away from the smoke outlet to form a groove 221, and the inner diameter of the notch of the groove 221 is larger than the outer diameter of the end surface of the smoke outlet. When the smoke pipe 100 is in a non-smoke exhaust state, the backflow prevention member 220 is buckled on the smoke outlet under the action of gravity, so that the smoke inlet pipe 111 is separated from the installation cavity 211. In this way, when the smoke pipe 100 is in a smoke exhaust state, the groove 221 can increase the contact area between the backflow prevention member 220 and the smoke, ensuring that the smoke can blow open the backflow prevention member 220, thereby improving the reliability of the gas water heater 10. In addition, when the smoke pipe 100 is in a non-smoke exhaust state, the backflow prevention member 220 is buckled on the smoke outlet, and the air intake direction at the smoke outlet and the flow direction of the cold air are set at an obtuse angle, so that the cold air cannot directly enter the smoke inlet pipe 111 through the smoke outlet, thereby improving the reliability of the first backflow prevention device 200.
[0047] As shown in Fig. 4, optionally, the first backflow prevention device 200 further includes a stopper 250, which is installed at the top of the installation cavity 211 and is located between the smoke inlet pipe 111 and the smoke outlet pipe 112. The stopper 250 is used to limit the rotation angle of the backflow prevention member 220 relative to the smoke inlet pipe 111. In this way, the stopper 250 can limit the maximum opening angle of the backflow prevention member 220 relative to the smoke outlet end, ensuring that the backflow prevention member 220 can be reset under the action of gravity and re-covered on the smoke outlet end after the smoke pipe 100 is switched to the non-smoke exhaust state, thereby improving the reliability of the first backflow prevention device 200.
[0048] Specifically in this embodiment, the limiting member 250 can be configured as a limiting frame, and the limiting frame can be installed on the top wall of the installation cavity 211 by welding, screwing, clamping, plugging or other connection methods.
[0049] As shown in FIG4 , in one embodiment, the edge of the backflow prevention member 220 is provided with a magnetic attraction portion 222, and the first backflow prevention device 200 further includes a magnetic attraction member 260, which is installed on the outside of the smoke outlet end. When the backflow prevention member 220 cover is set on the smoke outlet end, the magnetic attraction member 260 is used to apply magnetic attraction to the magnetic attraction portion 222. In this way, when the smoke pipe 100 is in a non-smoke exhaust state, the backflow prevention member 220 can maintain a sealed fit with the smoke outlet end under the combined action of gravity and magnetic force, thereby improving the reliability of the first backflow prevention device 200.
[0050] Among them, the number of magnetic members 260 and magnetic parts 222 can be flexibly adjusted according to the actual needs of use. The magnetic member 260 can be set as an electromagnet or a permanent magnet. The magnetic part 222 can be set as a permanent magnet or a metal block that can be attracted by a magnet. Specifically in this embodiment, the magnetic part 222 is located on the side of the anti-backflow member 220 away from the connecting member 240, and the magnetic member 260 is located at the bottom of the smoke outlet end and is set corresponding to the magnetic part 222.
[0051] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.
[0052] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0053] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.
[0054] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0055] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.
[0056] It should also be understood that when explaining the connection relationship or positional relationship of elements, although not explicitly described, the connection relationship and positional relationship are interpreted as including an error range, which should be within the acceptable deviation range of a specific value determined by those skilled in the art. For example, "approximately", "approximately" or "substantially" may mean within one or more standard deviations, which are not limited here.
[0057] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0058] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.
Claims
1. A gas water heater, characterized in that: include: Hot water body (400); a smoke pipe (100), the smoke pipe (100) being in communication with the hot water body (400); a first backdraft prevention device (200), wherein the first backdraft prevention device (200) is installed on the smoke pipe (100); as well as A second backdraft prevention device (300), wherein the second backdraft prevention device (300) is installed on the smoke pipe (100), and along the extension direction of the smoke pipe (100), the second backdraft prevention device (300) is located on a side of the first backdraft prevention device (200) close to the hot water body (400), and is spaced more than 300 mm from the first backdraft prevention device (200).
2. The gas water heater according to claim 1, characterized in that: Along the extension direction of the smoke pipe (100), the second backdraft prevention device (300) is spaced 500 mm from the first backdraft prevention device (200).
3. The gas water heater according to claim 1, characterized in that: The smoke pipe (100) comprises a first pipe section (110) for connecting to an external environment, and a second pipe section (120) for connecting to the hot water body (400); an axis of the first pipe section (110) and an axis of the second pipe section (120) are arranged at an angle; the first backdraft prevention device (200) is installed on the first pipe section (110), and the second backdraft prevention device (300) is installed on the second pipe section (120).
4. The gas water heater according to claim 3, characterized in that: The first pipe section (110) extends in a horizontal direction, and the second pipe section (120) extends in a vertical direction.
5. The gas water heater according to claim 3, characterized in that: The second anti-backdraft device (300) is located outside the hot water body (400); or, the second anti-backdraft device (300) is located inside the hot water body (400).
6. The gas water heater according to any one of claims 1 to 5, characterized in that: The first backflow prevention device (200) comprises a mounting body (210) and a backflow prevention member (220); the mounting body (210) is provided with a mounting cavity (211), and a smoke inlet (212) and a smoke outlet (213) both of which are in communication with the mounting cavity (211); the smoke pipe (100) comprises a first pipe section (110); the first pipe section (110) comprises a smoke inlet pipe (111) and a smoke outlet pipe (112) which are arranged at intervals; the smoke inlet pipe (111) extends into the mounting cavity (211) through the smoke inlet (212); the smoke outlet pipe (112) is installed at the smoke outlet (213) and the smoke outlet pipe (112) is installed at the smoke outlet (213). 3), and is used to connect the installation cavity (211) and the external environment, the backflow prevention member (220) can be rotatably arranged in the installation cavity (211), when the smoke pipe (100) is in a non-smoke exhaust state, the backflow prevention member (220) is covered on the smoke outlet end of the smoke inlet pipe (111) under the action of gravity, so that the smoke inlet pipe (111) is separated from the installation cavity (211), and when the smoke pipe (100) is in a smoke exhaust state, the backflow prevention member (220) is rotated away from the smoke outlet end under the action of smoke, so that the smoke inlet pipe (111) is connected to the installation cavity (211).
7. The gas water heater according to claim 6, characterized in that: The first backflow prevention device (200) further comprises a counterweight (230), wherein the counterweight (230) is mounted on the backflow prevention member (220).
8. The gas water heater according to claim 7, characterized in that: The first backflow prevention device (200) further comprises a connecting piece (240), the connecting piece (240) being mounted on the top of the mounting cavity (211) and located above the smoke outlet end, one side of the backflow prevention piece (220) being rotatably connected to the connecting piece (240), and the counterweight (230) being mounted on a side of the backflow prevention piece (220) away from the connecting piece (240).
9. The gas water heater according to claim 6, characterized in that: The backflow prevention member (220) is recessed toward a side away from the smoke outlet end to form a groove (221); the inner diameter of the notch of the groove (221) is larger than the outer diameter of the end surface of the smoke outlet end; when the smoke pipe (100) is in a non-smoke exhaust state, the backflow prevention member (220) is inverted on the smoke outlet end under the action of gravity, so that the smoke inlet pipe (111) is separated from the installation cavity (211).
10. The gas water heater according to claim 6, characterized in that: The first backflow prevention device (200) further comprises a limiting member (250), the limiting member (250) being installed at the top of the installation cavity (211) and located between the smoke inlet pipe (111) and the smoke outlet pipe (112), the limiting member (250) being used to limit the rotation angle of the backflow prevention member (220) relative to the smoke inlet pipe (111).