Premixing devices and gas equipment

Abstract

This application relates to a premixing device and a gasification equipment, including a device body, a swirling assembly, and a second gas conduit. The device body has a gas flow channel with a first gas inlet and a premixed gas outlet. The swirling assembly is disposed within the gas flow channel, axially along the channel. The first gas inlet is located upstream of the swirling assembly, and the premixed gas outlet is located downstream. The swirling assembly includes multiple guide vanes distributed around its axial direction. The airflow passing through the guide vanes has a radial velocity component and a tangential velocity component, thus forming a negative pressure zone in the middle of the end face of the swirling assembly near the premixed gas outlet. The second gas conduit penetrates the swirling assembly, and its outlet is located on the end face of the swirling assembly near the premixed gas outlet. Under the negative pressure, the second gas in the second gas conduit is drawn into the gas flow channel, preventing backflow of gas into the second gas conduit.

Description

Technical Field

[0001] This application relates to the field of gas water heater technology, and in particular to premixing devices and gas equipment. Background Technology

[0002] Gas water heaters and similar gas appliances rely on gas combustion to provide heat. To achieve high efficiency and low emissions, the gas and air are premixed before ignition, ensuring complete combustion and resulting in advantages such as lower pollutant emissions, higher flame temperature, and shorter flame length. However, when introducing air and gas, the airflow can obstruct the gas from entering the premixing space, and insufficient gas supply pressure can pose a risk of gas backflow. Summary of the Invention

[0003] Therefore, it is necessary to provide a premixing device and a gas equipment to address the problem of gas backflow. The swirling component causes the first gas flowing through it to have a radial velocity component and a tangential velocity component, thereby forming a negative pressure zone on the end face of the swirling component near the premixed gas outlet, which draws in the second gas in the second gas conduit and prevents the gas from backflowing into the second gas conduit.

[0004] A premixing device, comprising:

[0005] The device body has a gas flow channel, which has a first gas inlet and a premixed gas outlet.

[0006] A swirling assembly is disposed within the gas flow channel and is arranged axially along the gas flow channel. The first gas inlet is located upstream of the swirling assembly, and the premixed gas outlet is located downstream of the swirling assembly. The swirling assembly includes multiple guide vanes distributed around its own axial direction. The airflow passing through the guide vanes has a radial velocity component and a tangential velocity component.

[0007] A second gas conduit extends through the swirl assembly, and the outlet of the second gas conduit is located on the end face of the swirl assembly near the premixed gas outlet.

[0008] In one embodiment, the device body includes a venturi tube, the inner channel of which serves as the gas flow channel, and the swirling assembly is coaxially arranged within the inlet section of the venturi tube.

[0009] In one embodiment, the interface between the inlet section and the constriction section of the venturi tube is a first interface, and the distance between the end face of the swirl assembly near the premixed gas outlet and the first interface is no greater than 2.5 mm.

[0010] In one embodiment, the end face of the swirl assembly near the premixed gas outlet is coplanar with the first interface.

[0011] In one embodiment, the contraction angle α1 of the contraction section of the Venturi tube is 45° to 69°, the diffusion angle α2 of the diffusion section of the Venturi tube is 15° to 27°, the throat length of the Venturi tube is 30 mm to 45 mm, the diffusion section length of the Venturi tube is 10 mm to 17 mm, and the inlet section length of the Venturi tube is 13 mm to 20 mm.

[0012] In one embodiment, the inner diameter of the section of the second gas conduit that passes through the swirl assembly is 5 mm to 7.8 mm, the second gas conduit is disposed in the middle of the swirl assembly, the middle diameter of the swirl assembly is 10 mm to 20 mm, the inner diameter of the inlet section of the Venturi tube is 38 mm to 44 mm, the inner diameter of the throat of the Venturi tube is 32 mm to 38 mm, and the maximum inner diameter of the diffuser section of the Venturi tube is 40 mm to 48 mm.

[0013] Alternatively, the second gas conduit is interference-fitted with the middle of the swirl assembly.

[0014] In one embodiment, the central portion of the swirl assembly includes a central shaft sleeve arranged coaxially with the gas flow channel, and a second gas conduit axially penetrates the central shaft sleeve along the central shaft sleeve, with the outlet of the second gas conduit located on the end face of the central shaft sleeve near the premixed gas outlet.

[0015] In one embodiment, a seal is provided between the second gas conduit and the central sleeve.

[0016] In one embodiment, the premixing device further includes a fan inlet housing having an outlet and an installation port. The installation port is used to install a fan and communicates with the fan's outlet. The outlet of the fan inlet housing is aligned and communicated with the first gas inlet of the device body. The second gas conduit extends outward through the fan inlet housing, and a seal is provided between the second gas conduit and the fan inlet housing.

[0017] In one embodiment, the guide vanes of the swirl assembly are folded blades, the axial length of the folded blades is 16mm to 20mm, and the mounting angle r and the inlet angle r of the folded blades are... in and the exit angle r of the folded blade out All are between 40° and 80°.

[0018] A gas-fired device includes a combustion section and the aforementioned premixing device, wherein the combustion section is disposed at the premixed gas outlet.

[0019] The above solution provides a premixing device and a gasification equipment. The swirling assembly installed in the gas flow channel guides the first gas flowing in from the first gas inlet, ensuring that the first gas has a radial velocity component and a tangential velocity component after passing through the swirling assembly. This creates a negative pressure zone on the end face of the swirling assembly near the premixed gas outlet. The negative pressure provides suction for the second gas in the second gas conduit, making it easier for the second gas to enter the gas flow channel from the second gas conduit and preventing backflow of the second gas into the second gas conduit. The second gas introduced into the second gas conduit and the first gas passing through the swirling assembly mix downstream of the swirling assembly and can then be discharged from the premixed gas outlet. Attached Figure Description

[0020] Figure 1 This is a front view of the gas equipment described in this embodiment.

[0021] Figure 2 for Figure 1 The gas equipment shown is shown as a cross-sectional view along direction AA.

[0022] Figure 3 This is a schematic diagram of the premixing device described in this embodiment.

[0023] Figure 4 for Figure 3 The diagram shows a cross-sectional view of the Chinese tuyeres tube in the premixing device.

[0024] Figure 5 for Figure 3 A schematic diagram of the swirl assembly in the premixing device shown.

[0025] Figure 6 for Figure 5 The front view of the guide vanes inside the swirl assembly shown.

[0026] Figure 7 for Figure 5 Top view of the guide vanes of the swirl assembly shown.

[0027] Explanation of reference numerals in the attached figures:

[0028] 10. Premixing device; 11. Device body; 111. Gas flow channel; 1111. First gas inlet; 1112. Premixed gas outlet; 112. Venturi tube; 1121. Inlet section; 1122. Contraction section; 1123. Throat; 1124. Diffusion section; 113. Fan inlet housing; 1131. Mounting port; 12. Swirl assembly; 121. Central shaft sleeve; 122. Guide vane; 13. Second gas duct; 20. Gas equipment; 21. Combustion section. Detailed Implementation

[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] In some embodiments, this application provides a premixing device 10 for premixing two gases together, the premixing device 10 having a premixed gas outlet 1112 for discharging the premixed gas. Figure 1 and Figure 2 As shown, the premixing device 10 can be applied to a gas appliance 20, which includes a combustion section 21. The combustion section 21 is located at the premixed gas outlet 1112. Gas and air can be mixed in the premixing device 10 and then enter the combustion section 21 from the premixed gas outlet 1112 for combustion.

[0031] Alternatively, the premixing device 10 can also be used for other gas mixing applications.

[0032] like Figure 1 and Figure 2 As shown, in some embodiments, the premixing device 10 includes a device body 11, a swirl assembly 12, and a second gas conduit 13. The device body 11 has a gas flow channel 111, which has a first gas inlet 1111 and a premixed gas outlet 1112. The swirl assembly 12 is disposed within the gas flow channel 111, and is axially arranged along the gas flow channel 111. The first gas inlet 1111 is located upstream of the swirl assembly 12, and the premixed gas outlet 1112 is located downstream of the swirl assembly 12. The space downstream of the swirl assembly 12 on the gas flow channel 111 is a mixing channel for mixing the two gases, and the outlet of the mixing channel is the premixed gas outlet 1112.

[0033] The swirl assembly 12 includes multiple guide vanes 122 distributed around its axial direction. The airflow passing through the guide vanes 122 has a radial velocity component and a tangential velocity component.

[0034] The second gas conduit 13 passes through the swirl assembly 12, and the outlet of the second gas conduit 13 is located on the end face of the swirl assembly 12 near the premixed gas outlet 1112.

[0035] After the first gas enters the gas flow channel 111 through the first gas inlet 1111, it flows through the swirling assembly 12. After passing through the swirling assembly 12, the first gas has a radial velocity component and a tangential velocity component under the guiding action of each guide vane 122. As a result, a negative pressure zone is formed in the middle of the swirling assembly 12. The outlet of the second gas conduit 13 is formed in this negative pressure zone. Therefore, the second gas in the second gas conduit 13 will be subjected to the suction force generated by the negative pressure, making it easier for the second gas to enter the gas flow channel 111, effectively preventing the second gas from flowing back into the second gas conduit 13.

[0036] All guide vanes 122 of the swirl assembly 12 have a guiding function, and the guiding direction of each guide vane 122 can be decomposed into a radial component and a tangential component. Therefore, the first gas flowing through the swirl assembly 12 has a radial velocity component and a tangential velocity component. In this application, "radial" refers to the radial direction along the swirl assembly 12, and "tangential" refers to a direction perpendicular to the radial direction. Both the radial direction component and the radial velocity component are vectors, and the direction of these vectors is outward along the radial direction of the swirl assembly 12. Both the tangential direction component and the tangential velocity component are vectors, and the direction of these vectors is perpendicular to the radial direction of the swirl assembly 12.

[0037] In some embodiments, such as Figures 5 to 7 As shown, the central part of the swirl assembly 12 includes a central shaft sleeve 121, which is coaxially arranged with the gas flow channel 111. Figure 2 As shown, the second gas conduit 13 extends axially through the central sleeve 121, and the outlet of the second gas conduit 13 is located on the end face of the central sleeve 121 near the premixed gas outlet 1112.

[0038] Furthermore, to improve the sealing between the second gas conduit 13 and the central shaft sleeve 121, a sealing element can be provided between the second gas conduit 13 and the central shaft sleeve 121.

[0039] The swirl assembly 12 can be made of plastic, as can the central shaft sleeve 121 and the guide vanes 122. The swirl assembly can be injection molded.

[0040] Alternatively, the middle part of the swirl assembly 12 can also be a cylindrical member, through which the second gas conduit 13 passes axially. A seal can also be provided between the cylindrical member and the second gas conduit 13.

[0041] In some embodiments, the second gas conduit 13 extends through the middle of the swirl assembly 12, and the second gas conduit 13 is interference-fitted with the middle of the swirl assembly 12. For example, the second gas conduit 13 is interference-fitted with the central shaft sleeve 121.

[0042] The airfoil shape of the guide vanes 122 of the swirl assembly 12 includes, but is not limited to, folded vanes, straight vanes, fan vanes, and propeller vanes.

[0043] In one embodiment, such as Figures 5 to 7 As shown, the guide vanes 122 of the swirl assembly 12 are folded blades, with an axial length L4 of 16mm to 20mm. The mounting angle r and the inlet angle r of the folded blades are also specified. in The exit angle r of the folded blade out All are between 40° and 80°.

[0044] The first gas entering the airflow channel 111 flows mainly along the axial direction of the gas flow channel 111 before passing through the swirling assembly 12. After being guided by each guide vane 122, the flow direction is changed, forming a negative pressure zone, which provides additional suction for the second gas.

[0045] Furthermore, such as Figures 1 to 3 As shown, the premixing device 10 also includes a fan inlet housing 113, which has an outlet and a mounting port 1131. The mounting port 1131 is used to install the fan and is connected to the fan's outlet. The outlet of the fan inlet housing 113 is aligned and connected to the first gas inlet 1111 of the device body 11. After the fan is started, air can be blown from the first gas inlet 1111 into the gas flow channel 111. The first gas flows through the swirl assembly 12 and mixes with the second gas downstream of the swirl assembly 12.

[0046] The second gas conduit 13 extends outward through the blower inlet housing 113. A seal is provided between the second gas conduit 13 and the blower inlet housing 113 to ensure a tight seal between them. One end of the second gas conduit 13 is inserted into the swirl assembly 12, and the other end of the second gas conduit 13 is located outside the device body 11 for communication with the second gas supply device. The second gas can be fuel gas.

[0047] The second gas supply device can provide a certain forward force for the second gas, but this force may not be sufficient for high-power combustion applications. In this application, the negative pressure zone in the middle of the swirl assembly 12 adds a force to the second gas, making the second gas flow rate higher.

[0048] The fan installed at the mounting port 1131 of the fan access housing 113 can be a model 51F fan, so that the first gas flow velocity in the gas flow channel 111 meets the combustion requirements.

[0049] Furthermore, such as Figure 3 and Figure 4As shown, in some embodiments, the device body 11 includes a venturi tube 112, the inner channel of the venturi tube 112 is a gas flow channel 111, and the swirl assembly 12 is coaxially arranged in the inlet section 1121 of the venturi tube 112.

[0050] The Venturi tube 112 can accelerate the flow rate of the mixed gas, allowing the gas to flow out of the premixed gas outlet 1112 more quickly, thereby increasing the combustion efficiency of the premixed gas. Furthermore, the first gas flowing through the swirl assembly 12 has a radial velocity component and a tangential velocity component. In the Venturi tube 112, the flow rate of the first gas is further altered, resulting in a more homogeneous mixture of the first and second gases, thus improving combustion efficiency.

[0051] In some embodiments, the interface between the inlet section 1121 and the constriction section 1122 of the Venturi tube 112 is the first interface, and the distance between the end face of the swirling assembly 12 near the premixed gas outlet 1112 and the first interface is no greater than 2.5 mm. Limiting the distance between the starting interface (i.e., the first interface) of the swirling assembly 12 and the constriction section 1122 controls the space occupancy rate of the swirling assembly 12 on the constriction section 1122 as much as possible, ensuring the airflow velocity within the throat 1123.

[0052] In one embodiment, the middle part of the swirl assembly 12 is a central shaft sleeve 121, the end face of the central shaft sleeve 121 near the premixed gas outlet 1112 is located inside the inlet section 1121, and the distance between the end face of the central shaft sleeve 121 and the contraction section 1122 of the venturi tube 112 is no more than 2.5 mm.

[0053] In some embodiments, the interface between the inlet section 1121 and the constriction section 1122 of the Venturi tube 112 is the first interface, and the end face of the swirling assembly 12 near the premixed gas outlet 1112 is coplanar with the first interface. The outlet of the second gas conduit 13 is located exactly on the first interface, minimizing the adverse effects of the swirling assembly 12 on the gas flow rate in the Venturi tube 112 and reducing the airflow resistance in the throat 1123. Consequently, the supply pressure adjustment range of the second gas in the second gas conduit 13 is wider, preventing the first gas from flowing back into the second gas conduit 13 due to excessive resistance.

[0054] In one embodiment, the central part of the swirl assembly 12 is a central shaft sleeve 121, and the end face of the central shaft sleeve 121 near the premixed gas outlet 1112 is coplanar with the first interface.

[0055] In some embodiments, such as Figure 4As shown, the contraction angle α1 of the contraction section 1122 of the Venturi tube 112 is 45°–69°, and the diffusion angle α2 of the diffusion section 1124 of the Venturi tube 112 is 15°–27°. The length L1 of the throat 1123 of the Venturi tube 112 is 30 mm–45 mm, the length L2 of the diffusion section 1124 of the Venturi tube 112 is 10 mm–17 mm, and the length L3 of the inlet section 1121 of the Venturi tube 112 is 13 mm–20 mm.

[0056] The specific parameters of the Venturi tube 112 vary depending on the operating conditions and can be adjusted according to the actual conditions. However, the parameters must ultimately meet the above-mentioned range requirements to ensure that the gas supply pressure and mixing performance meet the combustion requirements. If the contraction angle α1 of the contraction section 1122 of the Venturi tube 112 is less than 45°, the concentration of the second gas in the mixed gas flowing out of the premixed gas outlet 1112 will fluctuate significantly. For combustion equipment, the second gas is combustion fuel, and the large fluctuation in combustion fuel concentration will ultimately result in an unstable flame.

[0057] In some embodiments, the inner diameter of the section of the second gas conduit 13 that passes through the swirl assembly 12 is 5 mm to 7.8 mm, and the central diameter D4 of the swirl assembly 12 is 10 mm to 20 mm. For example, the outer diameter of the central sleeve 121 can be 10 mm to 20 mm. The inner diameter D1 of the inlet section 1121 of the Venturi tube 112 is 38 mm to 44 mm, the inner diameter D2 of the throat 1123 of the Venturi tube 112 is 32 mm to 38 mm, and the maximum inner diameter D3 of the diffuser section 1124 of the Venturi tube 112 is 40 mm to 48 mm.

[0058] If the diameter of the middle part of the swirl assembly 12 is greater than 20mm, the swirl assembly 12 will occupy a large space in the airflow channel 111, resulting in a smaller flow rate at the location where the swirl assembly 12 is set in the airflow channel 111, leading to greater air resistance and affecting the gas flow rate. Therefore, the above parameter optimization design is carried out to achieve a good balance between the performance of the premixing device 10 and the gas equipment 20.

[0059] The middle part of the swirl assembly 12 mentioned in this application refers to the part located near the axis of the swirl assembly 12. Multiple guide vanes 122 are connected to the middle part of the swirl assembly 12 and are arranged in a radiating manner.

[0060] In some embodiments of this application, the gas appliance 20, in addition to including the premixing device 10 described in any of the foregoing embodiments, also includes a fan. The fan is installed at the mounting port 1131 of the fan inlet housing 113 and is used to blow air into the gas flow channel 111. The first gas can be air, and the second gas can be gas.

[0061] The gas equipment 20 provided by the above solution has a swirling component 12 installed in the gas flow channel 111, which guides the first gas flowing in from the first gas inlet 1111. This results in the first gas having a radial velocity component and a tangential velocity component after passing through the swirling component 12. Consequently, a negative pressure zone is formed in the middle of the end face of the swirling component 12 near the premixed gas outlet 1112. This negative pressure provides suction for the second gas in the second gas conduit 13, making it easier for the second gas to enter the gas flow channel 111 from the second gas conduit 13 and preventing the second gas from flowing back into the second gas conduit 13. The second gas introduced into the second gas conduit 13 and the first gas passing through the swirling component 12 mix downstream of the swirling component 12 and can then be discharged from the premixed gas outlet 1112.

[0062] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0063] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0065] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, 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 possible implementation.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0068] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A pre-mixing device, characterized by The premixing device comprises: a device body, which has a gas flow channel inside, the gas flow channel having a first gas inlet and a premix gas outlet; a cyclone assembly arranged in the gas flow channel, the cyclone assembly being arranged axially along the gas flow channel, the first gas inlet being located upstream of the cyclone assembly, and the premix gas outlet being located downstream of the cyclone assembly, the cyclone assembly comprising a plurality of guide vanes distributed around the axial direction of the cyclone assembly, the gas flow through the guide vanes having a radial velocity component and a tangential velocity component; a second gas conduit penetrating through the cyclone assembly, the outlet of the second gas conduit being located on the end face of the cyclone assembly close to the premix gas outlet; the middle part of the cyclone assembly comprises a middle shaft sleeve, which is coaxially arranged with the gas flow channel, the second gas conduit penetrating through the middle shaft sleeve along the axial direction of the middle shaft sleeve, the outlet of the second gas conduit being located on the end face of the middle shaft sleeve close to the premix gas outlet.

2. The premixing device of claim 1, wherein The device body comprises a Venturi tube, the passage in the Venturi tube being the gas flow channel, and the cyclone assembly being coaxially arranged in the inlet section of the Venturi tube.

3. The pre-mixing device of claim 2, wherein, The interface between the inlet section of the Venturi tube and the converging section of the Venturi tube is a first interface, and the spacing between the end face of the cyclone assembly close to the premix gas outlet and the first interface is not greater than 2.5 mm.

4. The pre-mixing device of claim 3, wherein, The end face of the cyclone assembly close to the premix gas outlet is coplanar with the first interface.

5. The premixing device of claim 2, wherein The converging angle a1 of the converging section of the Venturi tube is 45°-69°, the diffuser angle a2 of the diffuser section of the Venturi tube is 15°-27°, the throat length of the Venturi tube is 30 mm-45 mm, the length of the diffuser section of the Venturi tube is 10 mm-17 mm, and the length of the inlet section of the Venturi tube is 13 mm-20 mm.

6. The pre-mixing device of claim 2, wherein, The inner diameter of the pipe section of the second gas conduit penetrating through the cyclone assembly is 5 mm-7.8 mm, the second gas conduit is arranged in the middle part of the cyclone assembly, the diameter of the middle part of the cyclone assembly is 10 mm-20 mm, the inner diameter of the inlet section of the Venturi tube is 38 mm-44 mm, the inner diameter of the throat of the Venturi tube is 32 mm-38 mm, and the maximum inner diameter of the diffuser section of the Venturi tube is 40 mm-48 mm.

7. The pre-mixing device of claim 2, wherein, The second gas conduit is in interference fit with the middle part of the cyclone assembly.

8. The pre-mixing device of claims 1 to 7, characterized in that A sealing member is arranged between the second gas conduit and the middle shaft sleeve.

9. The pre-mixing device according to any one of claims 1 to 7, characterized in that The premixing device further comprises a fan access housing, which has an outlet and a mounting opening, the mounting opening being used for mounting a fan and communicating with the air outlet of the fan, the outlet of the fan access housing is in alignment and communication with the first gas inlet of the device body, the second gas conduit extends outwardly through the fan access housing, and a sealing member is arranged between the second gas conduit and the fan access housing.

10. The pre-mixing device according to any one of claims 1 to 7, characterized in that The guide vanes of the swirl assembly are folded blades, the axial length of which is 16mm to 20mm. The mounting angle r and the inlet angle r of the folded blades are also specified. in and the exit angle r of the folded blade out All are between 40° and 80°.

11. A gas appliance characterised in that, The premixing device comprises a combustion part and the premixing device according to any one of claims 1-10, and the combustion part is arranged at the premix gas outlet.

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