Noise-reducing centrifugal fan and gas water heater

Abstract

The present invention discloses a noise-reducing centrifugal fan and a gas water heater. The noise-reducing centrifugal fan comprises a volute; a flow guide device protruding from the inner wall of the volute, close to the air outlet of the volute, and gradually increasing in height from the inner wall of the volute along the air outlet direction; the flow guide device is formed with an air guide surface, which is the top surface of the flow guide device protruding from the inner wall of the volute, extending from the inside of the volute toward the air outlet, and used to guide the air outlet direction; and a blocking surface, which is the side of the flow guide device with the highest protruding height facing the air outlet. The flow guide device of the present invention can guide the direction of the airflow, guide the air out of the volute, and block the air from entering the volute from the air outlet. On the one hand, it reduces the noise caused by the formation of vortices in the airflow and the turbulence of the inlet and outlet air, and on the other hand, it can reduce the return air efficiency and improve the air outlet efficiency, thereby ensuring the normal and efficient operation of the fan.

Description

Technical Field

[0001] The present invention belongs to the field of household appliances, and in particular relates to a noise-reducing centrifugal fan and a gas water heater. Background Art

[0002] At present, the gas heaters on the market are mainly forced exhaust gas water heaters for their safety and stability. Multi-blade centrifugal fans are widely used in gas water heaters because they can provide higher wind pressure, are small in size and compact in structure, and have higher pressure coefficient and flow coefficient. The impeller is driven by a motor to rotate at high speed, and the centrifugal fan's volute collecting outlet discharges the air, providing the required amount of air for the combustion of the gas water heater. It is one of the core components of the gas water heater.

[0003] In the existing technology, the volute of a centrifugal fan is mostly made of sheet metal material, and the air outlet of the volute adopts a smooth outlet method. When the impeller rotates at high speed, the airflow impact and vibration of the volute of the fan is relatively large, and vortex backflow and other phenomena are prone to occur at the outlet of the fan, resulting in uneven outlet pressure distribution, large pressure difference, large volute vibration, and high noise.

[0004] A Chinese patent application number CN201821432418.X discloses a gas water heater fan, comprising a volute, a fan impeller arranged in the volute, a guide member and a motor; a noise reduction layer is provided on the inner wall of the volute, and the noise reduction layer has an uneven structure; the volute is provided with an air inlet and an air outlet; the output shaft of the motor is connected to the fan impeller; the guide member is installed at the air inlet of the volute; the guide member includes a plurality of axial flow blades, and the plurality of axial flow blades are arranged radially from the center of the air inlet toward the edge, and the axial flow blades are twisted.

[0005] In the above scheme, a twisted guide member is provided to change the angle at which the wind enters the fan impeller, thereby reducing the formation of vortices in the incoming wind. An uneven noise reduction layer is provided on the inner wall of the volute, which can reflect the noise remaining in the volute after the action of the guide member in multiple directions, thereby achieving the purpose of noise reduction. However, it cannot solve the vortex problem at the air outlet of the volute, nor can it solve the noise caused by the vortex there.

[0006] In view of the above technical deficiencies, the present invention is proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a centrifugal fan that can guide the air out of the volute and hinder the air from entering the volute from the air outlet, thereby reducing the generation of vortexes at the air outlet and achieving noise reduction.

[0008] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0009] A noise reduction centrifugal fan, comprising:

[0010] volute;

[0011] The guide device is protrudingly provided on the inner wall of the volute, close to the air outlet of the volute, and the height of the guide device protruding from the inner wall of the volute gradually increases along the air outlet direction;

[0012] The flow guide device is formed with:

[0013] The wind guide surface is the top surface of the guide device protruding from the inner wall of the volute, extending from the inside of the volute toward the air outlet, and is used to guide the direction of the air outlet;

[0014] The blocking surface is the side of the guide device with the highest protrusion facing the air outlet.

[0015] By adopting the above scheme, the guide device can guide the direction of the airflow, guide the air out of the volute, and hinder the air from entering the volute from the air outlet. On the one hand, it reduces the noise caused by the formation of vortexes in the airflow and the turbulence of the inlet and outlet air. On the other hand, it can reduce the return air efficiency and improve the air outlet efficiency, thereby ensuring the normal and efficient operation of the fan.

[0016] Furthermore, the upstream end of the air guide surface has a width, is arranged to fit the inner wall of the volute on the side opposite to the surface, and is connected to the inner wall;

[0017] The width of the downstream end of the guide device is not less than the width of the upstream end.

[0018] By adopting the above scheme, the upstream end of the air-guiding surface is arranged in contact with the inner wall of the volute and is connected with the inner wall of the volute, and will not hinder the airflow flowing thereto. The structure that gradually protrudes from the inner wall of the volute along the air outlet direction gradually guides the airflow to the air outlet, thereby achieving the function of guiding the airflow.

[0019] Furthermore, the flow guide device is formed by pressing the shell wall of the volute from the outside to the inside.

[0020] By adopting the above solution, the manufacture of the flow guide device is relatively simple. In addition, the pressing process can improve the strength of the volute.

[0021] Furthermore, the flow-guiding device includes at least two guiding parts, each of which is arranged on a different side of the inner wall of the volute, and each of the guiding parts cooperates with each other to achieve a wind-guiding effect.

[0022] Furthermore, the volute comprises:

[0023] The first housing forms the outer shell of one end of the volute in the axial direction and has an air inlet in the middle;

[0024] A second housing, constituting an outer shell of the other end of the volute in the axial direction;

[0025] The third housing forms the outer shell of the volute in the circumferential direction;

[0026] The guide device includes three guide parts, namely,

[0027] a first guide portion, disposed on the first housing;

[0028] a second guide portion, disposed on the second shell;

[0029] a third guide portion, provided on the third housing;

[0030] Preferably, the first guide portion and the second guide portion are arranged opposite to each other;

[0031] Preferably, the upstream ends of the three guide portions are at the same distance from the air outlet;

[0032] Preferably, the downstream ends of the three guide portions are at the same distance from the air outlet.

[0033] By adopting the above-mentioned solution, the airflow in multiple directions near the air outlet can be guided, the guiding effect can be improved, the air outlet efficiency can be guaranteed, the return air efficiency can be reduced, and the noise reduction effect can be improved. In addition, the two ends of the three guide parts are set at the same position. When the airflow reaches the guide device near the air outlet, the setting position of the three guide parts makes the guiding of the airflow between the guide parts have a mutual auxiliary effect, further improving the air outlet efficiency, reducing the return air efficiency, and improving the noise reduction effect. Furthermore, when the air enters the volute from the air outlet, it will be hindered by the sudden protrusion of the highest end of each guide part, thereby reducing the return air efficiency, further ensuring the air outlet efficiency, reducing the generation of vortexes, and reducing noise.

[0034] Furthermore, the side surface of the first guide portion facing the air inlet is in an arc structure, and the arc surface is coaxially arranged with the air inlet;

[0035] The side surface of the second guide portion facing the center of the circular portion of the second shell is in an arc structure, and the arc surface is coaxially arranged with the center of the circular portion of the second shell.

[0036] By adopting the above scheme, the central axis of the fan impeller is generally coaxially arranged with the central axis of the air inlet, and the two arcs are respectively coaxially arranged with the two shells, that is, coaxially arranged with the central axis of the fan impeller, so that when the fan impeller rotates, the airflow generated moves to the first guide part and the second guide part, and can flow along the centrifugal direction of the fan impeller through the arc guide surface, thereby reducing internal flow turbulence.

[0037] Furthermore, the distance between the side surface of the first guide portion away from the air inlet and the peripheral wall of the volute opposite to the side surface gradually increases along the air outlet direction;

[0038] The distance between the side surface of the second guide portion away from the central axis of the second housing and the peripheral wall of the volute opposite to the side surface gradually increases along the air outlet direction.

[0039] By adopting the above scheme, according to the rotation principle of the impeller fan of the centrifugal fan, the air flow is generally centrifugal motion, and the air is discharged along the inner wall of one side of the volute. The distance between the guide part and the air outlet side of the volute gradually increases from the inside to the outside, and the airflow is gradually guided to the opposite side of the original air outlet direction, which can reduce the wind pressure in different areas at the air outlet of the volute, thereby reducing the noise caused by the pressure difference.

[0040] Furthermore, at least the first guide portion and the second guide portion have the same height at the highest point protruding from the inner wall;

[0041] Preferably, the heights of the guide portions protruding from the highest points of the shells are the same.

[0042] Furthermore, it also includes a fan impeller, which is arranged inside the volute, and the impeller shaft is connected to the second housing;

[0043] The first guide portion and the second guide portion protrude from the highest point of the inner wall of the volute, and their projections on the fan impeller are located between the two ends of the fan impeller.

[0044] By adopting the above solution, the distance between the two guide parts protruding from the highest point of the inner wall is less than the axial length of the fan impeller, which makes the air inlet space smaller and difficult to let air in from the outside to the inside. In addition, under the action of the guide device, it does not affect the outward air flow of the fan impeller, so that the pressure at the air outlet is greater than the pressure outside the volute, further increasing the difficulty of letting air in from the air outlet.

[0045] Another object of the present invention is to provide a gas water heater having the above-mentioned noise-reducing centrifugal fan.

[0046] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0047] 1. The guide device can guide the direction of the airflow, guide the air out of the volute, and hinder the air from entering the volute from the air outlet. On the one hand, it reduces the noise caused by the formation of vortexes in the air flow and the turbulence of the inlet and outlet air. On the other hand, it can reduce the return air efficiency and improve the air outlet efficiency, ensuring the normal and efficient operation of the fan.

[0048] 2. The flow guide device includes multiple guide parts, which are respectively located on the three shells of the volute, and the two ends of the three guide parts are equidistant from the air outlet. When the airflow reaches the flow guide device near the air outlet, the guide parts have a mutual auxiliary effect on the guidance of the airflow, thereby improving the flow guidance effect, ensuring the air outlet efficiency, reducing the return air efficiency, and improving the noise reduction effect.

[0049] 3. The upstream end of the air-guiding surface of the guide device is fitted against the inner wall of the volute and then connected to the inner wall of the volute, which will not hinder the airflow to this place. The structure that gradually protrudes from the inner wall of the volute along the air outlet direction gradually guides the airflow to the air outlet, thereby achieving the function of guiding the air. On the other hand, when the air flows into the volute from the air outlet, it will be hindered by the sudden protrusion of the highest end of the guide part, thereby reducing the return air efficiency, further ensuring the air outlet efficiency, reducing the generation of vortexes, and reducing noise.

[0050] 4. The central axis of the fan impeller is generally coaxially arranged with the central axis of the air inlet, and the two arcs are coaxially arranged with the two shells respectively, that is, coaxially arranged with the central axis of the fan impeller, so that when the fan impeller rotates, the airflow generated moves to the first guide part and the second guide part, and flows along the centrifugal direction of the fan impeller through the arc surface, thereby reducing internal flow turbulence.

[0051] 5. According to the rotation principle of the impeller fan of the centrifugal fan, the air flow is generally centrifugal motion, and the air is discharged along the inner wall of one side of the volute. The distance between the guide part and the air outlet side of the volute gradually increases from the inside to the outside, and the air flow is gradually guided to the opposite side of the original air outlet direction, which can reduce the wind pressure in different areas at the air outlet of the volute, thereby reducing the noise caused by the pressure difference.

[0052] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0054] Figure 1 It is a structural schematic diagram of the noise reduction centrifugal fan of the present invention;

[0055] Figure 2 yes Figure 1 Schematic diagram from another angle;

[0056] Figure 3 yes Figure 2 Schematic diagram from another angle;

[0057] Figure 4 yes Figure 3 Schematic diagram from another angle;

[0058] Figure 5 It is a schematic diagram of the explosion structure of the noise reduction centrifugal fan of the present invention.

[0059] In the figure: 1. volute; 11. first shell; 111. air inlet; 12. second shell; 13. third shell; 14. air outlet; 15. volute tongue; 16. guide plate; 2. guide device; 21. first guide part; 22. second guide part; 23. third guide part; 3. fan impeller.

[0060] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0062] In the description of the present invention, it should be noted that the terms "upper", "inner", "outer", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0063] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0064] like Figures 1 to 5As shown, a noise-reducing centrifugal fan comprises a volute 1; a flow guide 2 protruding from the inner wall of the volute 1, near the air outlet 14 of the volute 1, with the height of the protrusion from the inner wall of the volute 1 gradually increasing along the air outlet direction; the flow guide 2 is formed with a wind guide surface, which is the top surface of the flow guide 2 protruding from the inner wall of the volute 1, extending from the interior of the volute 1 toward the air outlet 14 and used to guide the air outlet direction; and a blocking surface, which is the side of the flow guide 2 with the highest protrusion facing the air outlet 14. The flow guide 2 can guide the air out of the volute 1 and block the air from entering the volute 1 from the air outlet 14.

[0065] The guide device 2 of the present invention can guide the direction of the airflow, guide the air out of the volute 1, and hinder the air from entering the volute 1 from the air outlet 14. On the one hand, it reduces the noise caused by the formation of vortices in the airflow and the turbulence of the inlet and outlet winds. On the other hand, it can reduce the return air efficiency and improve the outlet air efficiency, thereby ensuring the normal and efficient operation of the fan.

[0066] like Figure 1 and Figure 2 As shown, the upstream end of the air guide surface has a width, is arranged to fit the inner wall of the volute 1 on the side opposite to the surface, and is connected to the inner wall. The width of the downstream end of the flow guide device 2 is not less than the width of the upstream end. The height of the upstream end of the air guide surface protruding from the inner wall of the volute 1 is close to zero.

[0067] Both ends of the wind guide surface have width, which is convenient for gathering wind and preventing the width of the wind guide surface from being too narrow, so that the airflow cannot enter the wind guide surface, or the airflow entering the wind guide surface is small, and the airflow cannot be guided or the guiding effect is poor.

[0068] The upstream end of the air-guiding surface of the present invention is arranged to fit the inner wall of the volute 1 and is connected to the inner wall of the volute 1, and will not hinder the airflow flowing thereto. The structure that gradually protrudes from the inner wall of the volute 1 along the air outlet direction gradually guides the airflow to the air outlet 14, thereby achieving the function of guiding the airflow.

[0069] The flow guide device 2 is formed by a flow guide block provided on the inner wall of the volute 1. The flow guide block is made of metal and connected to the volute 1 by integral molding or bonding, clamping, connecting pieces, etc.; or the flow guide block is made of plastic and is integrally molded with the volute 1 by injection molding.

[0070] and / or, such as Figure 1 As shown, the guide device 2 is formed by pressing the shell wall of the volute 1 from the outside to the inside. This arrangement makes the manufacture of the guide device 2 relatively simple and can also enhance the strength of the volute 1.

[0071] like Figure 1 and Figure 3As shown, the guide device 2 includes at least two guide parts, each of which is located on a different side of the inner wall of the volute 1, and the guide parts cooperate with each other to achieve a wind guiding effect.

[0072] The materials of the guide parts are the same or different; the configuration methods of the guide parts are the same or different.

[0073] like Figure 1 As shown, the volute 1 includes a first shell 11, which constitutes the outer shell of one end of the volute 1 in the axial direction, and an air inlet 111 is provided in the middle; a second shell 12 is arranged opposite to the first shell 11, constituting the outer shell of the other end of the volute 1 in the axial direction; a third shell 13 is located between the first shell 11 and the second shell 12, connecting the first shell 11 and the second shell 12, and constituting the outer shell of the volute 1 in the circumferential direction; the flow guide device 2 includes three guide parts, namely, a first guide part 21, which is arranged on the first shell 11; a second guide part 22, which is arranged on the second shell 12; and a third guide part 23, which is arranged on the third shell 13.

[0074] like Figure 1 and Figure 3 As shown, the first guide portion 21 and the second guide portion 22 are arranged opposite to each other.

[0075] Furthermore, the upstream ends of the three guide portions are at the same distance from the air outlet 14 , and the downstream ends of the three guide portions are at the same distance from the air outlet 14 .

[0076] As an embodiment, the third guide portion 23 is located between the first guide portion 21 and the second guide portion 22 and is equidistant from the first guide portion 21 and the second guide portion 22 .

[0077] As an implementation scheme, Figure 5 As shown, the upstream end of the first guide portion 21 is arranged with the same diameter as the air inlet 111, the upstream end of the second guide portion 22 is arranged radially along the central axis of the second shell 12, and the upstream end of the third guide portion 23 is perpendicular to the first guide portion 21 and the second guide portion 22 respectively.

[0078] by Figure 1 and Figure 3 Taking the placement position as an example, the ends of the first guide portion 21, the second guide portion 22 and the third guide portion 23 away from the air outlet 14 are located on the same vertical plane, and the ends of the first guide portion 21, the second guide portion 22 and the third guide portion 23 close to the air outlet 14 are also located on the same vertical plane, that is, the first guide portion 21 and the second guide portion 22 are symmetrically distributed, and the third guide portion 23 is sandwiched between the first guide portion 21 and the second guide portion 22.

[0079] The present invention has multiple guide parts, which are arranged in multiple directions on the inner wall of the volute 1, and can guide the airflow in multiple directions near the air outlet 14, improve the guiding effect, ensure the air outlet efficiency, reduce the return air efficiency, and thus achieve the effect of improving noise reduction. In addition, the setting positions of the two ends of the three guide parts are respectively the same. When the airflow reaches the guide device 2 near the air outlet 14, the setting positions of the three guide parts make the guiding of the airflow between the guide parts have a mutual auxiliary effect, further improving the air outlet efficiency, reducing the return air efficiency, and improving the noise reduction effect. Furthermore, when the air enters the volute 1 from the air outlet 14, it will be hindered by the sudden protrusion of the highest end of each guide part, thereby reducing the return air efficiency, further ensuring the air outlet efficiency, reducing the generation of vortexes, and reducing noise.

[0080] like Figure 2 As shown, a guide plate 16 is provided on the outside of the first shell 11, covering the outer periphery of the air inlet 111, and a guide port corresponding to the air inlet 111 is provided on the guide plate 16, which is used to guide the airflow from the air inlet 111 into the interior of the volute 1, thereby ensuring the air intake volume entering the interior of the volute 1 and improving the air intake efficiency.

[0081] The side surface of the first guide portion 21 facing the air inlet 111 is an arc-shaped structure, and the arc-shaped surface is coaxially arranged with the air inlet 111; the side surface of the second guide portion 22 facing the center of the circular part of the second shell 12 is an arc-shaped structure, and the arc-shaped surface is coaxially arranged with the center of the circular part of the second shell 12.

[0082] The arc edge of the arc surface structure of the first guide portion 21 arranged on the first shell 11 is arranged with the same diameter as the air inlet 111; the arc edge of the arc surface structure of the second guide portion 22 arranged on the second shell 12 is arranged with the same diameter as the center of the circular part of the second shell 12.

[0083] like Figure 2 As shown, the width of the downstream ends of the first guide portion 21 and the second guide portion 22 is greater than the width of the upstream end, and the downstream ends of the two arc-shaped surfaces are close to the downstream ends of the two guide portions and are connected to the guide portions through a connecting portion with the same height as the downstream ends of the arc-shaped surfaces.

[0084] Since the impeller axis of the fan impeller 3 is generally coaxially arranged with the central axis of the first shell 11, that is, the central axis of the air inlet 111, and the central axis of the second shell 12, the two arcs are respectively coaxially arranged with the two shells, that is, coaxially arranged with the central axis of the fan impeller 3, so that when the fan impeller 3 rotates, the airflow generated moves to the first guide part 21 and the second guide part 22, and can flow along the centrifugal direction of the fan impeller 3 through the arc structure, thereby reducing internal flow turbulence.

[0085] like Figure 4As shown, the distance between the side surface of the first guide portion 21 away from the air inlet 111 and the peripheral wall of the volute 1 opposite to the side surface gradually increases along the air outlet direction; the distance between the side surface of the second guide portion 22 away from the central axis of the second shell 12 and the peripheral wall of the volute 1 opposite to the side surface gradually increases along the air outlet direction.

[0086] The central axis of the second housing 12 is coaxial with the fan axis.

[0087] According to the rotation principle of the impeller fan of the centrifugal fan, the airflow is generally centrifugal motion, and the air is discharged from the inner wall of the volute 1 away from the volute tongue 15. The distance between the guide part and the air outlet side of the volute 1 gradually increases from the inside to the outside, and the airflow is gradually guided to the opposite side of the original air outlet direction, which can reduce the wind pressure in different areas at the air outlet of the volute 1, thereby reducing the noise caused by the pressure difference.

[0088] Furthermore, at least the first guide portion 21 and the second guide portion 22 have the same height at their highest points protruding from the inner wall; preferably, the height of the highest points protruding from the inner wall of each guide portion is the same.

[0089] As an embodiment, the first guide portion 21 and the second guide portion 22 are completely identical in size and structure.

[0090] Further, if Figure 2 As shown, each guide portion extends from its highest point protruding from the inner wall of the volute 1 toward the air outlet 14, and the distance each guide portion protrudes from the inner wall of the volute 1 gradually decreases along the extension direction, with the distal end of each guide portion protruding from the inner wall of the volute 1 at a distance greater than zero. With the highest point of each guide portion as the boundary, the slope on the side closer to the air outlet 14 is much greater than the slope on the side farther from the air outlet 14. Preferably, the slope on the side closer to the air outlet 14 is ten times greater than the slope on the side farther from the air outlet 14.

[0091] As an implementation scheme, the three guide portions have the same length along the extension direction, and their positions protruding from the highest points of the inner walls of each shell correspond to each other. On the same vertical plane, the slopes close to the air outlet 14 and away from the air outlet 14 are also the same.

[0092] The corners of each guide portion protruding from the highest point of the inner wall of the volute 1 are arc corners, which smoothly transition to the side surfaces of each guide portion along the air outlet direction.

[0093] This arrangement not only reduces airflow resistance and facilitates airflow guidance, but also creates a protrusion inward from the air outlet 14, causing a sudden obstruction of airflow as it enters the air outlet 14, increasing resistance and reducing the efficiency of air entering the air outlet 14. The three guide portions, protruding from the highest points of the inner walls of each housing, correspond to each other, gradually directing the airflow toward the opposite side. At the highest point, the aperture is minimized, i.e., the wind pressure is minimized. This further reduces the pressure differential between different areas near the air outlet 14, thus reducing noise.

[0094] like Figure 3 and Figure 5 As shown, the noise-reducing centrifugal fan of the present invention further includes a fan impeller 3 disposed within the volute 1. The projections of the first guide portion 21 and the second guide portion 22 protruding from the highest point of the inner wall of the volute 1 onto the fan impeller 3 are located between the two ends of the fan impeller 3. That is, the distance H1 between the highest point of the first guide portion 21 and the second guide portion 22 protruding from the inner wall of the volute 1 is less than the axial length H2 of the fan impeller 3. This results in a smaller air intake space after entering the volute 1 through the air outlet 14, making it difficult for air to enter from the outside in. Furthermore, the action of the flow guide device 2 does not affect the outward flow of air from the fan impeller 3, resulting in the pressure at the air outlet 14 being greater than the pressure outside the volute 1, further increasing the difficulty of air entering from the air outlet 14.

[0095] Another object of the present invention is to provide a gas water heater having the above-mentioned noise-reducing centrifugal fan.

[0096] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments of equivalent changes using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. The implementation schemes in the above-mentioned embodiments can also be further combined or replaced. However, any simple modifications, equivalent changes and modifications made to the above-mentioned embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A noise-reducing centrifugal fan, characterized in that: include, volute; The guide device is protrudingly provided on the inner wall of the volute, close to the air outlet of the volute, and the height of the guide device protruding from the inner wall of the volute gradually increases along the air outlet direction; The flow guide device is formed with: The wind guide surface is the top surface of the guide device protruding from the inner wall of the volute, extending from the inside of the volute toward the air outlet, and is used to guide the direction of the air outlet; The blocking surface is the side of the guide device with the highest protrusion facing the air outlet; The air guide device includes a first guide portion and a second guide portion that are symmetrically arranged, and a third guide portion sandwiched between the first guide portion and the second guide portion; the side surfaces of the first guide portion and the second guide portion close to the air inlet axis are both curved structures, and both curved surface structures are coaxially arranged with the air inlet; The first guide portion, the second guide portion, and the third guide portion each have a width at one end close to the air inlet.

2. A noise reduction centrifugal fan according to claim 1, characterized in that: The upstream end of the air guide surface has a width, is arranged to fit the inner wall of the volute on the side opposite to the surface, and is connected to the inner wall; The width of the downstream end of the guide device is not less than the width of the upstream end.

3. The noise reduction centrifugal fan according to claim 2, characterized in that: The flow guide device is formed by pressing the shell wall of the volute from the outside to the inside.

4. The noise reduction centrifugal fan according to claim 3, characterized in that: The volute comprises: The first housing forms the outer shell of one end of the volute in the axial direction and has an air inlet in the middle; A second housing, constituting an outer shell of the other end of the volute in the axial direction; The third housing forms the outer shell of the volute in the circumferential direction; a first guide portion, disposed on the first housing; a second guide portion, disposed on the second shell; The third guide portion is arranged on the third shell.

5. The noise reduction centrifugal fan according to claim 4, characterized in that: The downstream ends of the three guide portions are at the same distance from the air outlet.

6. The noise reduction centrifugal fan according to claim 5, characterized in that: The side surface of the second guide portion facing the center of the circular portion of the second shell is in an arc structure, and the arc surface is coaxially arranged with the center of the circular portion of the second shell.

7. The noise reduction centrifugal fan according to claim 6, characterized in that: The distance between the side surface of the first guide portion away from the air inlet and the peripheral wall of the volute opposite to the side surface gradually increases along the air outlet direction; The distance between the side surface of the second guide portion away from the central axis of the second housing and the peripheral wall of the volute opposite to the side surface gradually increases along the air outlet direction.

8. A noise-reducing centrifugal fan according to any one of claims 5 to 7, characterized in that: At least the first guide portion and the second guide portion have the same height as the highest point protruding from the inner wall.

9. The noise-reducing centrifugal fan according to claim 8, characterized in that: Preferably, the heights of the guide portions protruding from the highest points of the shells are the same.

10. A noise-reducing centrifugal fan according to any one of claims 5 to 7, characterized in that: It also includes a fan impeller, which is arranged inside the volute, and the impeller shaft is connected to the second housing; The first guide portion and the second guide portion protrude from the highest point of the inner wall of the volute, and their projections on the fan impeller are located between the two ends of the fan impeller.

11. A gas water heater, characterized in that: A noise-reducing centrifugal fan as claimed in any one of claims 1 to 10.

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