Full-premixing fuel gas wall-hanging stove and silencer thereof

Abstract

The invention discloses a full-premixing fuel gas wall-hanging stove and a silencer thereof. The full-premixing fuel gas wall-hanging stove comprises a pipe body, cylindrical silencing cotton and a flow guide part. The flow guide part comprises a mounting frame and a flow guide cone, the flow guide cone is fixed in the tube body, the barrel-shaped silencing cotton is attached to the inner wall of the tube body and surrounds the outer portion of the flow guide cone, the flow guide cone comprises a forward cone and a reverse cone which are connected on the same bottom face, and the flow guide cone can guide airflow to pass stably, reduce air inlet pressure drop and guarantee stable value of the Venturi tube; the combustion stability is improved, generation of thermoacoustic oscillation noise is reduced from the source, the flow guide cone can enable sound waves to enter the cylindrical silencing cotton at a large angle and turn back in the pipe body, the sound waves are effectively absorbed by the silencing cotton, meanwhile, the flow guide part forms a variable-diameter channel, air is compressed or expanded to deform, sound energy is further consumed, and the noise reduction effect is achieved. And outward propagation of thermo-acoustic oscillation noise is inhibited. The barrel-shaped silencing cotton is formed by combining the sound absorption cotton layer with high-density honeycomb holes and the sound insulation felt layer, and sound waves of all frequency bands are effectively reduced.

Description

Technical Field

[0001] This invention relates to the technical field of fully premixed gas wall-hung boilers, and in particular to a fully premixed gas wall-hung boiler and its silencer. Background Technology

[0002] As a core device for domestic heating, fully premixed combustion wall-hung boilers employ positive pressure combustion, requiring the gas to be fully premixed with air at a specific air coefficient before combustion. Therefore, if the pressure drop in the intake system is too large, the gas-to-air equivalence ratio will be unstable, leading to uneven distribution of the velocity and concentration fields downstream of the combustion chamber injection inlet. This imbalance in the flame heat release rate results in unstable local pressure fluctuations, generating thermoacoustic oscillation noise with an intensity exceeding 60 dB, making the surrounding environment noisy and negatively impacting the user experience.

[0003] For the air intake system of a fully premixed combustion wall-hung boiler, the air inlet of the DC inverter fan is connected to a venturi tube for pressure tapping. The resulting air intake structure is located inside the equipment housing. This air intake structure is one of the main pathways for the thermal oscillation noise generated by the combustion chamber to propagate inside the equipment housing. To reduce noise at the air intake structure, there are two key directions: First, the noise energy generated by the combustion chamber should be consumed as it passes through the air intake structure and is transmitted to the equipment housing, thus suppressing the outward propagation of noise. Second, the airflow through the air intake structure should be guided smoothly into the fan, reducing the pressure drop of the air intake system, ensuring the stability of the gas-to-air equivalence ratio during equipment operation, improving combustion stability, and reducing the generation of thermal oscillation noise at the source.

[0004] Existing fully premixed combustion wall-hung boilers do not employ the above-mentioned solutions to reduce noise at the air intake structure. Only some wall-hung boilers use simple sound insulation materials for noise reduction at the air intake structure, resulting in limited noise reduction effects. Existing technologies need improvement. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a fully premixed gas wall-hung boiler and its silencer to solve the above problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention first provides a silencer for a fully premixed gas wall-hung boiler, comprising a tube body, a cylindrical sound-absorbing cotton, and a flow guide. The tube body has a Venturi tube interface and an air inlet at both ends; the cylindrical sound-absorbing cotton is attached to the inner wall of the tube body; the flow guide includes a mounting frame and a flow guide cone, the flow guide cone being fixed to the tube body by the mounting frame, and the cylindrical sound-absorbing cotton surrounding the outside of the flow guide cone. The flow guide cone and the cylindrical sound-absorbing cotton are located on the same central axis and do not contact each other. The flow guide cone includes a forward cone and a reverse cone connected by a common bottom surface. The forward cone extends from its bottom surface to its apex towards the air inlet, and the reverse cone extends from its bottom surface to its apex away from the air inlet.

[0008] Preferably, the tubular sound-absorbing cotton includes a layer of sound-absorbing cotton and a layer of sound-insulating felt stacked together, and the sound-absorbing cotton layer has a plurality of honeycomb-shaped pores.

[0009] Preferably, the sound-absorbing cotton layer is polyurethane sound-absorbing cotton, the sound-insulating felt layer is glass fiber rock wool composite felt layer, and the tube body is a polypropylene tube body.

[0010] Preferably, the tubular sound-absorbing cotton has a funnel-shaped inner surface structure with a gradually shortening inner diameter along the direction from the bottom surface of the reverse cone to its apex.

[0011] Preferably, the pipe body includes a bent pipe cavity area and a flow guiding pipe cavity area connected end to end, the venturi tube interface is opened at the tail end of the bent pipe cavity area, the air inlet is opened at the head end of the flow guiding pipe cavity area, the flow guiding pipe cavity area is cylindrical, and the cylindrical sound-absorbing cotton and the flow guiding part are accommodated in the flow guiding pipe cavity area.

[0012] Preferably, the mounting frame is provided with a connecting crossbar, which extends radially across the air inlet and the vertex of the positive cone is connected to the midpoint of the connecting crossbar.

[0013] Preferably, a dust filter is fixed on the mounting frame, and the dust filter covers the air inlet.

[0014] The present invention also provides a fully premixed gas wall-hung boiler, which includes a fan, a venturi tube, and a silencer as described above, wherein the venturi tube interface in the silencer is connected to the fan through the venturi tube.

[0015] The technical effects achieved by the above-mentioned technical solution of the present invention mainly include:

[0016] The silencer for a fully premixed gas wall-mounted boiler provided by this invention extends a tube body onto the venturi tube of the air inlet structure. The tube body houses a cylindrical sound-absorbing cotton and a guide cone. The guide cone is composed of two cones sharing a common base. The cylindrical sound-absorbing cotton is attached to the inner wall of the tube body and surrounds the outside of the guide cone. The guide cone and the cylindrical sound-absorbing cotton are located on the same central axis and do not contact each other. Therefore, after the airflow enters the tube body, the airflow can maintain a smooth transition under the guidance of the guide cone, reducing the inlet pressure drop. The tube body effectively extends the air inlet structure, buffering the airflow before it enters the constriction section of the venturi tube. This prevents excessive airflow pressure fluctuations caused by direct airflow from outside the air inlet structure into the venturi tube, reducing the impact of airflow pressure fluctuations on the venturi tube readings and ensuring smoother gas flow during equipment operation. Maintaining a stable air equivalence ratio improves combustion stability, reduces the generation of thermoacoustic oscillation noise, and enhances equipment operational stability. Since the air inlet is one of the main pathways for this noise to propagate from the combustion chamber into the equipment housing, a guide cone is used to direct sound waves at a large angle into the cylindrical sound-absorbing cotton and cause them to refract within the tube. As the sound waves travel within the cotton, their acoustic energy is converted into heat energy and consumed. Simultaneously, the guide section forms a variable-diameter channel, causing the air, the medium for sound wave propagation, to compress or expand, thereby consuming acoustic energy. This silencer simultaneously suppresses the outward propagation of thermoacoustic oscillation noise and reduces its generation at the source, resulting in quieter operation and a significantly improved user experience.

[0017] The cylindrical sound-absorbing cotton is composed of a combination of a sound-absorbing cotton layer and a sound-insulating felt layer. The sound-absorbing cotton layer, which is the core sound-absorbing structure, is made of polyurethane sound-absorbing cotton with multiple honeycomb-shaped pores, which can effectively absorb mid-to-high frequency noise. The sound-insulating felt layer is a glass fiber rock wool composite felt layer, which can effectively isolate low-frequency noise, achieving comprehensive coverage and reduction of sound waves in all frequency bands.

[0018] By adding a dust filter to the air inlet, the blockage of the burner and heat exchanger by dust in the air is reduced, further improving the stability of combustion and reducing the generation of thermal vibration noise. Attached Figure Description

[0019] Figure 1 A perspective view of the silencer of a fully premixed gas wall-hung boiler provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram showing the connection between the silencer and the fan via a venturi tube.

[0021] Figure 3 This is a structural exploded view of the muffler;

[0022] Figure 4 This is a structural exploded view of the muffler from another perspective;

[0023] Figure 5 For the corresponding Figure 2 A front view of the muffler in the image;

[0024] Figure 6 For the corresponding Figure 5 Cross-sectional view of the muffler along section line A-A';

[0025] Figure 7 For the corresponding Figure 1 Side view of the muffler in the middle;

[0026] Figure 8 and Figure 9 For the corresponding Figure 7 A cross-sectional schematic diagram of the muffler along section line B-B' in the diagram;

[0027] Figure 10 This is a microstructure diagram of the cylindrical sound-absorbing cotton 2 in the silencer.

[0028] The reference numerals in the above figures are as follows:

[0029] Pipe body 1, bend in the pipe cavity 11, flow guide pipe cavity 12, venturi tube interface 101, air inlet 102;

[0030] 2. Tubular sound-absorbing cotton layer; 21. Sound-absorbing cotton layer; 22. Sound-insulating felt layer; 23. Rubber and plastic sound-insulating cotton layer; 201. Funnel-shaped inner surface;

[0031] Flow guide 3, mounting frame 31, connecting crossbar 311, flow guide cone 32, forward cone 321, reverse cone 322, dust filter 33;

[0032] Fan 400;

[0033] Venturi tube 500. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0035] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related are omitted. Figure 8 The arrows in the diagram represent exemplary propagation paths of airflow. Figure 9 The arrows in the diagram represent exemplary propagation paths of sound waves.

[0036] like Figure 1As shown, an embodiment of the present invention provides a silencer for a fully premixed gas wall-hung boiler, which includes a tube body 1, a cylindrical sound-absorbing cotton 2, and a flow guide 3.

[0037] The tube body 1 has a Venturi tube interface 101 and an air inlet 102 at both ends, respectively, combined with Figure 1 and Figure 2 As shown, the Venturi tube interface 101 is used to connect to the Venturi tube 500; combined with Figures 3 to 6 As shown, the cylindrical sound-absorbing cotton 2 is attached to the inner wall of the pipe body 1; the flow guide 3 includes a mounting frame 31 and a flow guide cone 32. The flow guide cone 32 is fixed inside the pipe body 1 by the mounting frame 31. The cylindrical sound-absorbing cotton 2 surrounds the outside of the flow guide cone 32. The flow guide cone 32 and the cylindrical sound-absorbing cotton 2 are located on the same central axis and do not contact each other. The flow guide cone 32 includes a forward cone 321 and a reverse cone 322 connected by a common bottom surface, that is, a double cone structure in which the bottom surfaces of the two cones completely overlap. The forward cone 321 extends from its bottom surface to its apex towards the air inlet 102, and the reverse cone 322 extends from its bottom surface to its apex away from the air inlet 102.

[0038] The working principle of the silencer of the above-mentioned fully premixed gas wall-hung boiler is as follows:

[0039] Firstly, refer to Figure 7 and Figure 8 As shown, the airflow outside the silencer enters the pipe body 1 from the air inlet 102. The gap between the guide cone 32 and the cylindrical sound-absorbing cotton 2 is part of the airflow channel. Based on the forward cone 321 facing the air inlet 102, the airflow first travels along its cone surface towards the reverse cone 322 under the guidance of the forward cone 321, and then travels towards the depth of the pipe body 1 under the guidance of the reverse cone 322, until it finally reaches the venturi tube interface 101. Since the cross-sectional area of ​​the forward cone 321 and the reverse cone 322 gradually changes and they share the same bottom surface and are continuously arranged, the airflow can maintain a smooth transition, significantly reducing turbulence generation and reducing the intake pressure drop. Based on the setting of the guide cone 32, the tube body 1 can extend the air inlet structure and act as a buffer section before the airflow enters the contraction section of the Venturi tube 500. This avoids the airflow outside the air inlet structure from directly entering the Venturi tube 500 and causing excessive airflow pressure fluctuations. This reduces the impact of airflow pressure fluctuations on the value of the Venturi tube 500, which helps to ensure the stability of the gas-air equivalence ratio during equipment operation, improves combustion stability, reduces the generation of thermal and acoustic vibration noise at the source, and can reduce the occurrence of resonance of the whole machine components due to unstable combustion, thus improving the stability of equipment operation.

[0040] Secondly, refer to Figure 7 and Figure 9As shown, when thermal oscillation noise is generated, it propagates outward through the venturi tube interface 101 and the air inlet 102 of the silencer. When the sound wave enters the interval area between the guide cone 32 and the cylindrical sound-absorbing cotton 2, the sound wave is reflected back inside the tube body 1 due to the reflection of the outer surface of the guide cone 32. During this process, the sound wave enters the cylindrical sound-absorbing cotton 2 on the outer periphery of the guide cone 32. Due to the air viscosity resistance and the vibration friction between the air and the material pore wall, the sound energy is converted into heat energy and consumed. The structure of the guide cone 32 increases the incident angle of the sound wave on the cylindrical sound-absorbing cotton 2, resulting in higher sound absorption efficiency. At the same time, the guide part 3 forms a variable diameter channel, which causes the air, as the medium for sound wave propagation, to be compressed or expanded and deformed, thereby consuming sound energy and suppressing the outward propagation of noise.

[0041] Reference Figure 10 As shown, in this embodiment, the cylindrical sound-absorbing cotton 2 includes a layered sound-absorbing cotton layer 21 and a sound-insulating felt layer 22. The sound-absorbing cotton layer 21 has multiple honeycomb-shaped pores. When sound waves are incident on the sound-absorbing cotton layer 21, the sound waves penetrate into the material along these honeycomb-shaped pores, and the sound energy is gradually converted into heat energy and consumed, achieving 60% to 80% sound energy consumption of mid-to-high frequency noise. The sound-insulating felt layer 22 can block low-frequency noise that has not been absorbed by the sound-absorbing cotton layer 21, achieving comprehensive coverage and weakening of sound waves in all frequency bands and improving the effect of suppressing noise propagation. Furthermore, a rubber-plastic sound-insulating cotton layer 23 is provided on the side of the sound-absorbing cotton layer 21 facing away from the sound-insulating felt layer 22.

[0042] For example, the sound-absorbing cotton layer 21 is polyurethane sound-absorbing cotton, which has advantages such as high temperature resistance, good chemical stability, good toughness, and flame retardancy reaching V0 level, and is suitable for the needs of wall-hung boilers. Preferably, its density is 100kg / m³, the honeycomb holes are circular with a diameter of 20mm, a hole depth of 10mm, and a hole wall thickness of 10mm. The thickness of the rubber and plastic sound insulation cotton layer 23 is set to 10mm. The sound insulation felt layer 22 is a glass fiber rock wool composite felt layer with a thickness of 3~5mm and an adaptability range of -20℃~200℃. The tube body 1 is a polypropylene tube body, which can be formed by vacuum forming process. The cylindrical sound-absorbing cotton 2 can be adhered to the inner wall of the tube body 1 by adhesive backing.

[0043] like Figure 6 As shown, the inner wall of the cylindrical sound-absorbing cotton 2 is configured to adapt to the variable diameter structure of the flow guide cone 32. Along the direction from the bottom surface of the reverse cone 322 to its apex, the cylindrical sound-absorbing cotton 2 forms a funnel-shaped inner surface 201 structure with a gradually shortening inner diameter length.

[0044] Because the internal space of a standard wall-hung boiler is compact, the pipe body 1 is designed with sufficient length to reduce airflow pressure and to provide enough space to accommodate the cylindrical sound-absorbing cotton 2 and the guide section 3. Figure 3 , Figure 4 and Figure 6As shown, the pipe body 1 includes a bent pipe cavity area 11 and a flow guiding pipe cavity area 12 connected end to end. The Venturi tube interface 101 is opened at the tail end of the bent pipe cavity area 11, and the air inlet 102 is opened at the head end of the flow guiding pipe cavity area 12. The flow guiding pipe cavity area 12 is cylindrical. The cylindrical sound-absorbing cotton 2 and the flow guiding part 3 are accommodated in the flow guiding pipe cavity area 12. The bent pipe cavity area 11 allows the air inlet 102 to avoid the inner wall of the wall-hung boiler shell, preventing the air inlet 102 from facing the inner wall of the wall-hung boiler shell, ensuring the unobstructed flow of the air inlet 102. At the same time, it allows the pipe body 1 to be set longer by making appropriate use of the space inside the wall-hung boiler. The bent pipe cavity area 11 has little impact on the airflow pressure, and the curvature of the bent pipe cavity area 11 can be reasonably adjusted.

[0045] Specifically, the mounting frame 31 is provided with a connecting crossbar 311, which extends radially across the air inlet 102. The apex of the positive cone 321 is connected to the midpoint of the connecting crossbar 311, so that the guide cone 32 is fixed on the same central axis as the cylindrical sound-absorbing cotton 2.

[0046] Because dust and impurities often exist in the air, their intake can cause blockages in the combustion system channels, leading to adverse conditions such as reduced load. It can also cause unstable combustion and generate thermal vibration noise. To further reduce noise caused by this factor, a dust filter 33 is fixed to the mounting frame 31, covering the air inlet 102. In this embodiment, the dust filter 33 is preferably a 300-mesh stainless steel filter to reduce the blockage of the burner and heat exchanger by airborne dust. The setting of the dust filter 33 also needs to consider the airflow required for normal operation. Its specific airflow is matched to the actual diameter of the pipe body 1, and the specific value can be adjusted according to needs, calculated based on the principle that the flow rate is proportional to the 2.5th power of the pipe diameter.

[0047] This invention also provides a fully premixed gas wall-hung boiler, combined with Figure 1 and Figure 2 As shown, it includes a fan 400, a venturi tube 500, and a silencer as described above. The venturi tube interface 101 in the silencer is connected to the fan 400 through the venturi tube 500.

[0048] Based on the multi-faceted reduction effect of the above-mentioned silencer on thermal vibration noise, the overall noise of the fully premixed gas wall-hung boiler can be reduced by 15~20dB, which is superior to existing technology equipment.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0050] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A silencer for a fully premixed gas wall-hung boiler, characterized in that, include: The pipe body (1) has a venturi tube interface (101) and an air inlet (102) at its two ends respectively. Tubular sound-absorbing cotton (2), the tubular sound-absorbing cotton (2) is attached to the inner wall of the tube (1); The guide section (3) includes a mounting frame (31) and a guide cone (32). The guide cone (32) is fixed inside the pipe body (1) by the mounting frame (31). The cylindrical sound-absorbing cotton (2) surrounds the outside of the guide cone (32). The guide cone (32) and the cylindrical sound-absorbing cotton (2) are located on the same central axis and do not contact each other. The guide cone (32) includes a forward cone (321) and a reverse cone (322) connected by a common bottom surface. The forward cone (321) extends from its bottom surface to its top surface towards the air inlet (102). The reverse cone (322) extends from its bottom surface to its top surface away from the air inlet (102).

2. The silencer for a fully premixed gas wall-hung boiler according to claim 1, characterized in that, The tubular sound-absorbing cotton (2) includes a layer of sound-absorbing cotton (21) and a layer of sound-insulating felt (22) stacked together, and the sound-absorbing cotton (21) has multiple honeycomb-shaped pores.

3. The silencer for a fully premixed gas wall-hung boiler according to claim 2, characterized in that, The sound-absorbing cotton layer (21) is polyurethane sound-absorbing cotton, the sound insulation felt layer (22) is glass fiber rock wool composite felt layer, and the pipe body (1) is a polypropylene pipe body.

4. The silencer for a fully premixed gas wall-hung boiler according to claim 1, characterized in that, Along the direction from the bottom surface of the reverse cone (322) toward its apex, the tubular sound-absorbing cotton (2) forms a funnel-shaped inner surface (201) structure with a gradually shortening inner diameter length.

5. The silencer for a fully premixed gas wall-hung boiler according to claim 1, characterized in that, The pipe body (1) includes a bent pipe cavity area (11) and a flow guiding pipe cavity area (12) connected end to end. The Venturi tube interface (101) is opened at the end of the bent pipe cavity area (11), and the air inlet (102) is opened at the beginning of the flow guiding pipe cavity area (12). The flow guiding pipe cavity area (12) is cylindrical, and the cylindrical sound-absorbing cotton (2) and the flow guiding part (3) are accommodated in the flow guiding pipe cavity area (12).

6. The silencer for a fully premixed gas wall-mounted boiler according to claim 1, characterized in that, The mounting frame (31) is provided with a connecting crossbar (311), which extends radially across the air inlet (102) and the vertex of the positive cone (321) is connected to the midpoint of the connecting crossbar (311).

7. The silencer for a fully premixed gas wall-hung boiler according to claim 1, characterized in that, A dust filter (33) is fixed on the mounting frame (31), and the dust filter (33) covers the air inlet (102).

8. A fully premixed gas wall-hung boiler, characterized in that, It includes a fan (400), a venturi tube (500), and a silencer as described in any one of claims 1 to 7, wherein the venturi tube interface (101) in the silencer is connected to the fan (400) via the venturi tube (500).

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