Air inlet structure of fan, fan and gas water heater

Abstract

The invention relates to the technical field of draught fans, particularly provides an air inlet structure of a draught fan, the draught fan and a gas water heater, and aims to solve the problem that an existing draught fan cannot avoid large noise on the premise that the efficiency of the draught fan is guaranteed. In order to achieve the purpose, the air inlet structure comprises an inner air guide ring, an outer air guide ring and an air guide structure, and a first air inlet channel is formed in the inner air guide ring; the outer air guide ring is sleeved outside the inner air guide ring, and a second air inlet channel is formed between the outer air guide ring and the inner air guide ring; the air guide structure is arranged to prevent airflow from axially entering the second air inlet channel from the second air inlet channel. According to the arrangement mode, the air volume is not increased and the pressure head of the fan is not reduced when the rotating speed of the fan is the same, and the efficiency of the fan is ensured. And noise is prevented from leaking from the second air inlet channel. And the air inlet of the fan can be rectified, so that the airflow can pass through the fan more uniformly, and the efficiency of the fan can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fans, and particularly provides an air inlet structure of a fan, a fan and a gas water heater. Background Art

[0002] Household gas water heaters are generally forced exhaust machines, that is, they supply air forcibly through a centrifugal fan to provide the air required for combustion and blow out the exhaust gas generated by combustion. However, the current fan design is likely to cause large eddy currents in the impeller inside the fan and low fan efficiency. On the other hand, the air inlet of the fan is a centralized opening, and this air inlet structure is likely to cause noise leakage of the fan, resulting in relatively large noise at the rated speed.

[0003] To reduce the overall combustion noise of the gas water heater, reducing the fan noise is one of the effective ways. In order not to lose the fan performance, generally a silencer is added at the fan inlet. This silencer is a sound insulation cover or sound absorption cotton or an acoustic sound absorption structure, and the noise leakage can be reduced to a certain extent through the silencer; however, the silencer does not reduce the noise caused by the eddy current inside the fan and the silencer structure is complex and the cost is relatively high. Currently, few products use a fan silencer.

[0004] Correspondingly, there is a need in the art for a new air inlet structure of a fan, a fan and a gas water heater to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problems, that is, to solve the problem that the existing fan cannot avoid relatively large noise while ensuring the fan efficiency.

[0006] In a first aspect, the present invention provides an air inlet structure of a fan, characterized in that the air inlet structure includes: an inner air guide ring, and the inner air guide ring is formed with a first air inlet channel; an outer air guide ring, the outer air guide ring is sleeved outside the inner air guide ring, and a second air inlet channel is formed between the outer air guide ring and the inner air guide ring; a wind guiding structure, and the wind guiding structure is arranged to block the airflow from axially entering the second air inlet channel from the second air inlet channel.

[0007] In the case of adopting the above technical solution, on the one hand, the inner air guide ring reduces the overall air inlet area, so as to ensure that when the fan speed is the same, the air volume does not increase and the fan head does not decrease, ensuring the fan efficiency. The air guide structure blocks the airflow from axially entering the second air inlet channel into the second air inlet channel. This design helps to prevent the generation of eddy currents in the fan, because eddy currents will reduce the efficiency of the fan. This design also helps to rectify the air inlet of the fan, making the airflow pass through the fan more evenly, which can improve the efficiency of the fan. Since the air guide structure can block the airflow from axially entering the second air inlet channel, this design also blocks the leakage of noise from the second air inlet channel. And this design method has a simple structure and can reduce costs. In short, the above setting method can not only ensure the fan efficiency, avoid excessive fan noise, but also reduce costs.

[0008] In an alternative technical solution of the air inlet structure of the above fan, the air guide structure includes a first annular outer plate and a second annular outer plate, and an annular guide channel is formed between the first annular outer plate and the second annular outer plate, and the annular guide channel is communicated with the second air inlet channel.

[0009] In the case of adopting the above technical solution, the annular guide channel formed between the first annular outer plate and the second annular outer plate can effectively guide the airflow into the second air inlet channel, thereby improving the working efficiency of the fan. This structure can make the airflow enter the fan more evenly and smoothly, reducing the energy loss caused by the vortex of the airflow. Since the airflow flows evenly in the annular guide channel, the noise generated by the rapid change of the airflow can be reduced. The design of the first annular outer plate and the second annular outer plate also increases the stability of the fan structure. In addition, these two annular outer plates can enhance the rigidity of the whole system, making the fan more stable during operation, reducing the noise generated by vibration and the possibility of damaging the fan.

[0010] In an alternative technical solution of the air inlet structure of the above fan, the first annular outer plate is arranged on the outer periphery of the air inlet end of the inner air guide ring, the second annular outer plate is arranged on the outer periphery of the air inlet end of the outer air guide ring, and the first annular outer plate is arranged outside the second annular outer plate.

[0011] In an alternative technical solution of the air inlet structure of the above fan, the diameter of the outer air guide ring is D1, the inner diameter of the impeller of the fan is D2, where 0.9D2 > D1 > 0.7D2; and / or the diameter of the inner air guide ring is D3, where 0.25D1 > D3 > 0.15D1.

[0012] In the case of adopting the above technical solution, designing the diameter of the outer air guide ring to be approximately close to the inner diameter of the impeller can reduce the internal eddy current in the impeller under the condition of constant fan speed, thereby improving the fan head and fan efficiency. The above-mentioned dimensional relationship between the inner air guide ring and the outer air guide ring can prevent the space between the inner air guide ring and the outer air guide ring from being too small, thus avoiding excessive squeezing of the air flow when it enters the fan and ensuring the air volume supply. By precisely controlling the diameter ratio of the inner air guide ring and the outer air guide ring, the flow path of the air flow can be effectively controlled. This helps to improve the efficiency of the fan, reduce energy loss, and also reduce noise.

[0013] In an alternative technical solution of the air inlet structure of the above-mentioned fan, a first outward flange is provided at the air outlet end of the inner air guide ring, and a second outward flange is provided at the air outlet end of the outer air guide ring.

[0014] In the case of adopting the above technical solution, it can cause the air flow to diffuse towards the edge of the impeller. Combining with the first air inlet channel, the air flow can flow into the impeller more evenly. The design of the first outward flange and the second outward flange also helps to better guide the air flow and make it flow into the fan interior more smoothly. This can improve the working efficiency of the fan and reduce energy loss. It also helps to reduce the eddy motion generated at the air outlet end of the second air inlet channel, thereby reducing the generation of noise. By improving the smoothness of the air flow, the noise can be significantly reduced and the user experience can be improved. In addition, it can effectively block the path of noise propagation, help reduce the leakage of noise from the air inlet, and thus reduce the noise impact.

[0015] In an alternative technical solution of the air inlet structure of the above-mentioned fan, the first outward flange protrudes from the second outward flange.

[0016] In an alternative technical solution of the air inlet structure of the above-mentioned fan, the inner air guide ring and the outer air guide ring are concentrically arranged.

[0017] In the case of adopting the above technical solution, it can provide a more direct and smoother channel for the air flow, help reduce the air flow eddy motion, and improve the working efficiency of the fan. The concentrically arranged inner and outer air guide rings help to balance the weight distribution of the fan, thereby improving the running stability of the fan and reducing the vibration and noise caused by unbalanced loads. And it can also make the wind force more concentrated, which is beneficial to improving the working efficiency of the fan. It can also make the inner air guide ring and the outer air guide ring support each other, improving the strength and durability of the entire fan structure. In addition, it can save installation space and facilitate the installation and maintenance of the fan. Therefore, the design of concentrically arranging the inner air guide ring and the outer air guide ring is very helpful for improving the efficiency, stability, structural strength of the fan and saving space.

[0018] In an alternative technical solution of the air inlet structure of the above-mentioned fan, the outer diameters of the first annular outer plate and the second annular outer plate are equal.

[0019] On the other hand, the present invention also provides a blower, characterized in that the blower includes the air inlet structure described in any of the above embodiments, wherein the outer air guide ring is connected to the air inlet of the blower.

[0020] On the other hand, the present invention also provides a gas water heater, characterized in that the gas water heater includes the blower described above. Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention, the following will briefly introduce the drawings required for use in the description of the specific embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is the schematic structural diagram (one) of the blower of the present invention;

[0023] Figure 2 is the perspective view of the air inlet structure of the blower of the present invention;

[0024] Figure 3 is the sectional view of the air inlet structure of the blower of the present invention;

[0025] Figure 4 is the schematic structural diagram (two) of the blower of the present invention;

[0026] Figure 5 is Figure 4 the sectional view at A-A in

[0027] Figure 6 is the schematic structural diagram (three) of the blower of the present invention.

[0028] Description of the Reference Numerals:

[0029] 1 - Blower; 11 - Air inlet; 12 - Air outlet; 13 - Motor; 14 - Impeller; 15 - Volute; 2 - Inner air guide ring; 21 - First air inlet channel; 22 - First outward flange; 3 - Outer air guide ring; 31 - Second air inlet channel; 32 - Second outward flange; 4 - First annular outer plate; 5 - Second annular outer plate; 6 - Guide channel. Detailed Embodiments

[0030] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention. Those skilled in the art can make adjustments according to needs to adapt to specific application scenarios. For example, although the description in the specification is based on a centrifugal fan, the present invention can also use various other types of fans, as long as the fan can ensure the fan efficiency and reduce noise by setting the air inlet structure of the present invention.

[0031] It should be noted that in the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0032] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] As Figures 1 to 6 shown, in order to solve the problem that the existing fans cannot avoid excessive noise while ensuring the fan efficiency. The present invention provides an air inlet structure for a fan 1, the fan 1 is a centrifugal fan, and the air inlet structure includes an inner air guide ring 2, an outer air guide ring 3, and a air guide structure. Among them, the inner air guide ring 2 is formed with a first air inlet passage 21; the outer air guide ring 3 is sleeved outside the inner air guide ring 2, and a second air inlet passage 31 is formed between the outer air guide ring 3 and the inner air guide ring 2; the air guide structure is arranged to block the airflow from axially entering the second air inlet passage 31. Optionally, the inner air guide ring 2 is a hollow cylindrical structure. It can be understood that the air guide structure does not prevent the airflow from entering the second air inlet passage 31 from other directions than the axial direction.

[0034] In the case of adopting the above technical solution, on the one hand, the inner air guide ring 2 reduces the overall air inlet area, so as to ensure that when the rotational speed of the fan 1 is the same, the air volume does not increase and the head of the fan 1 does not decrease, ensuring the efficiency of the fan 1. The air guide structure blocks the airflow from axially entering the second air inlet passage 31, and this design helps to prevent the generation of eddy currents inside the fan 1, because eddy currents will reduce the efficiency of the fan 1. This design also helps to rectify the air inlet of the fan 1, making the airflow pass through the fan 1 more evenly, which can improve the efficiency of the fan 1. Since the air guide structure can block the airflow from axially entering the second air inlet passage 31, this design also blocks the leakage of noise from the second air inlet passage 31. And this design method has a simple structure and can reduce costs. In short, the above setting method can not only ensure the efficiency of the fan 1, but also avoid excessive noise of the fan 1 and reduce costs.

[0035] As a possible implementation manner, the air guide structure includes a first annular outer plate 4 and a second annular outer plate 5. An annular guide channel 6 is formed between the first annular outer plate 4 and the second annular outer plate 5, that is, there is a gap between the first annular outer plate 4 and the second annular outer plate 5 to form the annular guide channel 6, and the annular guide channel 6 communicates with the second air inlet passage 31. It can be understood that the air inlet of the annular guide channel 6 is located in the radial direction of the inner and outer air guide rings, and this air inlet is also annular.

[0036] The annular guide channel 6 formed between the first annular outer plate 4 and the second annular outer plate 5 can effectively guide the airflow into the second air inlet passage 31, thereby improving the working efficiency of the fan 1. This structure can make the airflow enter the fan 1 more evenly and smoothly, reducing the energy loss caused by the eddy motion of the airflow. Since the airflow flows evenly in the annular guide channel 6, the noise generated due to the rapid change of the airflow can be reduced. The design of the first annular outer plate 4 and the second annular outer plate 5 also increases the structural stability of the fan 1. In addition, these two annular outer plates can enhance the rigidity of the entire system, making the fan 1 more stable during operation, reducing the noise generated by vibration and the possibility of damaging the fan 1.

[0037] As a possible implementation manner, the first annular outer plate 4 is arranged on the outer periphery of the air inlet end of the inner air guide ring 2, the second annular outer plate 5 is arranged on the outer periphery of the air inlet end of the outer air guide ring 3, and the first annular outer plate 4 is arranged outside the second annular outer plate 5. It can be understood that the air inlet ends of the inner air guide ring 2 and the outer air guide ring 3 are both the ends far from the inner cavity of the fan 1. Correspondingly, the air outlet ends of the inner air guide ring 2 and the outer air guide ring 3 are both the ends close to the inner cavity of the fan 1. The first annular outer plate 4 is arranged outside the second annular outer plate 5, that is, the first annular outer plate 4 is farther from the air inlet 11 of the fan 1 than the second annular outer plate 5. This structure can make the airflow enter the fan 1 more smoothly, reducing the energy loss caused by the eddy motion of the airflow.

[0038] Possibly, the inner air guide ring 2 and the first annular outer plate 4 are integrally formed, and the outer air guide ring 3 and the second annular outer plate 5 are integrally formed, so as to ensure the smoothness of the air flow. There are various specific implementation manners in which the outer air guide ring 3 is sleeved on the inner air guide ring 2. For example, the first annular outer plate 4 and the second annular outer plate 5 are connected by bolts, or the inner air guide ring 2 and the outer air guide ring 3 are connected by bolts, etc. Further, the bolts can be evenly arranged in the circumferential direction of the first annular outer plate 4 and the second annular outer plate 5. Among them, the bolts can be replaced with other connection structures, such as snap fasteners, etc.

[0039] As a possible implementation manner, the diameter of the outer air guide ring 3 is D1, and the inner diameter of the impeller 14 of the blower 1 is D2, where 0.9D2 > D1 > 0.7D2.

[0040] The applicant has found through research that in order to ensure sufficient combustion and wind pressure resistance of the gas water heater, the blower 1 needs to be designed with a high head. If the inlet diameter of the blower 1 is smaller than the inner diameter of the impeller 14, it will cause a large eddy current inside the impeller 14 of the blower 1 and low efficiency of the blower 1. The diameter of the outer air guide ring 3 of the present invention is designed to be approximately close to the inner diameter of the impeller 14, which can reduce the eddy current inside the impeller 14 without changing the rotational speed of the blower 1, thereby improving the head and efficiency of the blower 1.

[0041] As a possible implementation manner, the diameter of the inner air guide ring 2 is D3, where 0.25D1 > D3 > 0.15D1.

[0042] Setting such a ratio limit can prevent the space between the inner air guide ring 2 and the outer air guide ring 3 from being too small, thereby avoiding excessive squeezing of the air flow when it enters the blower 1 and ensuring the supply of air volume. By precisely controlling the diameter ratio of the inner air guide ring 2 and the outer air guide ring 3, the flow path of the air flow can be effectively controlled. This helps to improve the efficiency of the blower 1, reduce energy loss, and also reduce noise.

[0043] As a possible implementation manner, the air outlet end of the inner air guide ring 2 is provided with a first outward flanging 22, and the air outlet end of the outer air guide ring 3 is provided with a second outward flanging 32.

[0044] This setting method can make the air flow diffuse towards the edge of the impeller 14. Combined with the first air inlet channel 21, the air flow can flow into the impeller 14 more evenly. The design of the first outward flanging 22 and the second outward flanging 32 also helps to better guide the air flow, making it flow into the blower 1 more smoothly. This can improve the working efficiency of the blower 1 and reduce energy loss. It also helps to reduce the vortex generated at the air outlet end of the second air inlet channel 31, thereby reducing the generation of noise. By improving the smoothness of the air flow, the noise can be significantly reduced and the user experience can be improved. In addition, it can effectively block the path of noise propagation, helping to reduce the leakage of noise from the air inlet 11, thereby reducing the noise impact.

[0045] As a possible implementation, the first outward flanging 22 protrudes from the second outward flanging 32. In other words, the first outward flanging 22 extends more axially into the interior of the fan 1 compared to the second outward flanging 32. The protruding design of the first outward flanging 22 can more effectively prevent the air flow from generating a backflow inside the fan 1, protect the components inside the fan 1, and improve the durability of the fan 1. The protruding design of the first outward flanging 22 can also better block noise, help prevent noise from leaking out through the air inlet 11, and improve the user experience.

[0046] As a possible implementation, the inner air guide ring 2 and the outer air guide ring 3 are concentrically arranged.

[0047] The concentrically arranged inner and outer air guide rings 3 can provide a more direct and smoother channel for the air flow, help reduce air flow vortices, and improve the working efficiency of the fan 1. The concentrically arranged inner and outer air guide rings 3 help balance the weight distribution of the fan 1, thereby improving the running stability of the fan 1 and reducing vibrations and noises caused by unbalanced loads. Moreover, it can also make the wind force more concentrated, which is beneficial to improving the working efficiency of the fan 1. It can also make the inner air guide ring 2 and the outer air guide ring 3 support each other, improving the strength and durability of the entire structure of the fan 1. In addition, it can save installation space and facilitate the installation and maintenance of the fan 1. Therefore, the design of concentrically arranging the inner air guide ring 2 and the outer air guide ring 3 is very helpful for improving the efficiency, stability, structural strength of the fan 1 and saving space.

[0048] As a possible implementation, the outer diameters of the first annular outer plate 4 and the second annular outer plate 5 are equal.

[0049] This design can make the air flow inside the fan 1 be evenly distributed, avoid uneven air flow distribution caused by different sizes, and further improve the working efficiency of the fan 1. The design of equal outer diameters of the first annular outer plate 4 and the second annular outer plate 5 helps balance the weight distribution of the fan 1, makes the fan 1 more stable during operation, and reduces vibrations and noises caused by unbalanced centers of gravity. In addition, the design of equal outer diameters simplifies the production and installation processes, reduces production costs, and improves the installation convenience.

[0050] It can be understood that the above possible implementations can be used in cross - combination, so as to combine new implementations to be applicable to more specific application scenarios.

[0051] On the other hand, the present invention also provides a blower 1, which includes the air inlet structure described in any of the above embodiments. Among them, the outer air guide ring 3 is connected to the air inlet 11 of the blower 1, so that the inner air guide ring 2 is located in the middle of the air inlet 11. There are various specific implementation manners for the connection between the outer air guide ring 3 and the air inlet 11 of the blower 1. For example, the outer air guide ring 3 is connected to the air inlet 11 through the second annular outer plate 5, or the outer air guide ring 3 is directly connected to the air inlet 11. The specific connection can be by bolt connection, snap connection, welding, etc. The present invention does not make specific limitations on it.

[0052] After the blower 1 of the present invention has the above air inlet structure, on the one hand, it can reduce the eddy current inside the impeller 14, thereby improving the head and efficiency of the blower 1. On the other hand, it can rectify the air inlet of the blower 1 and block the leakage of noise, thereby reducing the overall machine noise. The blower 1 with this structure is simple to implement, has a good noise reduction effect, and low cost.

[0053] As a possible implementation manner, the blower 1 of the present invention includes a volute 15, a motor 13 and an impeller 14. Among them, the impeller 14 is arranged inside the volute 15, the motor 13 can be arranged on the volute 15, and the output shaft of the motor 13 is connected to the impeller 14 to drive the impeller 14 to rotate. An air inlet 11 as described above is provided on the volute 15 corresponding to the impeller 14 axially, and an air outlet 12 of the volute 15 is provided on the volute 15 at the outer periphery of the impeller 14.

[0054] Among them, the impeller 14 of the blower 1 can be coaxially arranged with the inner air guide ring 2 and the outer air guide ring 3. Since the impeller 14 is coaxially arranged with the inner air guide ring 2 and the outer air guide ring 3, the load of the impeller 14 can be effectively balanced, and the vibration and noise generated during the operation of the blower 1 can be reduced. And the vibration can be reduced, so it is also beneficial to extend the service life of the blower 1.

[0055] On the other hand, the present invention also provides a gas water heater, which includes the blower 1 introduced above.

[0056] Specifically, the blower 1 can be connected to the smoke exhaust duct of the gas water heater to be responsible for discharging the waste gas generated during the combustion process to ensure the safe operation of the water heater. Or the air outlet 12 of the blower 1 is connected to the air inlet 11 of the burner through a duct or an air pipe, and the function of this duct or air pipe is to guide the air blown out by the blower 1 to the burner. Among them, the blower 1 can be fixed on the casing of the gas water heater by screws or other fixing devices to ensure its stability during operation.

[0057] After the gas water heater of the present invention is equipped with the above-mentioned blower 1, air can be more effectively guided to the burner, enabling the gas to burn fully, thereby improving the combustion efficiency of the water heater. It can reduce the vortex of the air flow, lower the noise of the blower 1, and make the water heater operate more quietly. It can enhance the stability of the blower 1, reduce the vibration during operation, and improve the operating stability of the water heater.

[0058] It should be noted that the above-mentioned embodiments are only used to illustrate the principle of the present invention and are not intended to limit the protection scope of the present invention. Without departing from the principle of the present invention, those skilled in the art can adjust the above structure so that the present invention can be applied to more specific application scenarios.

[0059] For example, as an alternative embodiment, although the air guiding structure of the present invention is described by taking the first annular outer plate 4 and the second annular outer plate 5 as examples, this is not intended to limit the protection scope of the present invention. As long as the air guiding structure is configured to block the air flow from axially entering the second air inlet channel 31, its setting method can be adjusted. For example, the air guiding structure only includes the first annular outer plate 4, the first annular outer plate 4 is provided on the outer periphery of the inner air guiding ring 2, and the outer diameter of the first annular outer plate 4 is greater than the diameter of the outer air guiding ring 3, which can also block the air flow from axially entering the second air inlet channel 31, thereby reducing noise and ensuring the efficiency of the blower 1. Or a ring structure can be provided on the air inlet 11 of the blower 1. The ring structure is provided outside the second air inlet channel 31 and has an air inlet spacing from the air inlet 11 of the second air inlet channel 31, and the projection of the ring structure in the axial direction covers the second air inlet channel 31, etc. These adjustments do not deviate from the principle of the present invention and are all within the protection scope of the present invention.

[0060] For example, as an alternative embodiment, although the present invention is introduced by setting the first outward flange 22 at the air outlet end of the inner air guiding ring 2 and the second outward flange 32 at the air outlet end of the outer air guiding ring 3, this is not intended to limit the protection scope of the present invention. For example, the settings of the first outward flange 22 and the second outward flange 32 can be omitted. These adjustments do not deviate from the principle of the present invention and are all within the protection scope of the present invention.

[0061] So far, the technical solutions of the present invention have been described in combination with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. An air inlet structure of a fan, characterized in that, The air inlet structure includes: An inner air guide ring, which forms a first air inlet channel; An outer air guide ring, which is sleeved outside the inner air guide ring, and a second air inlet channel is formed between the outer air guide ring and the inner air guide ring; An air guiding structure, which is arranged to block the airflow from axially entering the second air inlet channel from the second air inlet channel.

2. The air inlet structure of the blower according to claim 1, characterized in that The air guiding structure includes a first annular outer plate and a second annular outer plate, and an annular guiding channel is formed between the first annular outer plate and the second annular outer plate, and the annular guiding channel is communicated with the second air inlet channel.

3. The air inlet structure of the blower according to claim 2, characterized in that The first annular outer plate is arranged on the outer periphery of the air inlet end of the inner air guide ring, the second annular outer plate is arranged on the outer periphery of the air inlet end of the outer air guide ring, and the first annular outer plate is arranged outside the second annular outer plate.

4. The air inlet structure of the blower according to claim 1, characterized in that The diameter of the outer air guide ring is D1, and the inner diameter of the impeller of the blower is D2, wherein, 0.9D2 > D1 > 0.7D2; and / or The diameter of the inner air guide ring is D3, wherein, 0.25D1 > D3 > 0.15D1.

5. The air inlet structure of the blower according to claim 1, characterized in that A first outward flanging is provided at the air outlet end of the inner air guide ring, and a second outward flanging is provided at the air outlet end of the outer air guide ring.

6. The air inlet structure of the blower according to claim 5, characterized in that The first outward flanging protrudes from the second outward flanging.

7. The air inlet structure of the blower according to claim 1, characterized in that The inner air guide ring and the outer air guide ring are concentrically arranged.

8. The air inlet structure of the blower according to claim 2, characterized in that The outer diameters of the first annular outer plate and the second annular outer plate are equal.

9. A fan, characterized in that, The blower includes the air inlet structure according to any one of claims 1 to 8, wherein the outer air guide ring is connected to the air inlet of the blower.

10. A gas water heater, characterized in that, The gas water heater includes the blower according to claim 9.

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