A counter-rotating local fan silencer system

Abstract

The present invention discloses a counter-rotating local fan silencer system, comprising a housing housing in which the local fan is placed, an expanded cavity induced draft muffler installed at the local fan air inlet, and an expanded cavity outlet muffler installed at the local fan air outlet, wherein the radius of the induced draft inlet of the expanded cavity induced draft muffler is greater than the radius of the end connected to the local fan air inlet, and the radius of the outlet end of the expanded cavity outlet muffler is equal to the radius of the end connected to the local fan air outlet, and a sound-absorbing layer is provided in the inner wall and inner cavity of the housing of the expanded cavity induced draft muffler and the expanded cavity outlet muffler. The present invention combines the expanded cavity induced draft muffler and the expanded cavity outlet muffler with the housing housing to comprehensively control airflow vortex, acoustic energy, mechanical noise, etc., and can achieve a 40dB absorption volume without affecting ventilation, so that the sound can be reduced to a minimum of 70dB, fully meeting the national standard requirement of below 85dB. People working in the system can communicate normally without being affected, thereby improving the comfort of the working environment of the staff.

Description

Technical Field

[0001] The invention relates to a counter-rotating local fan silencing system, belonging to the technical field of silencing equipment. Background Art

[0002] Local ventilation fans, also known as local fans, are commonly used in mines. To achieve high transmission efficiency, counter-rotating fans are commonly used in existing technology. Mining local fans are a major source of noise in mines, with noise levels often reaching 100-110dB, significantly exceeding national noise standards. Reducing noise levels not only protects the health of underground workers but also improves the working environment and increases production efficiency.

[0003] The noise of mining fans primarily comes from aerodynamic noise generated by the blades striking the air. Existing technologies employ various methods to reduce this noise, including adjusting fan structure and installing silencers. However, these reductions fall short of the national standard of 85dB. Most devices achieve only a 14dB reduction, consistently exceeding 85dB. Furthermore, in the pursuit of noise reduction, some fans may even compromise ventilation efficiency. Summary of the Invention

[0004] Through research, the present invention provides a counter-rotating local fan silencing system that can meet the requirements of national standards.

[0005] In order to achieve the above-mentioned purpose, the technical means adopted by the present invention are: a counter-rotating local fan silencer system, comprising a box cover in which the local fan is placed, an expansion cavity induced air silencer installed at the local fan air inlet, and an expansion cavity outlet air silencer installed at the local fan air outlet, the radius of the air inlet of the expansion cavity induced air silencer is greater than the radius of the connection end with the local fan air inlet, the radius of the air outlet end of the expansion cavity outlet silencer is equal to the radius of the connection end with the local fan air outlet, and a sound absorption layer is arranged on the inner wall and inner cavity of the shell of the expansion cavity induced air silencer and the expansion cavity outlet air silencer.

[0006] Furthermore, the distance between the different sound absorbing layers is proportional to the thickness of the sound absorbing layer.

[0007] Furthermore, the box cover is a sound-absorbing and sound-insulating box, which has a lower box and a box cover. Both the lower box and the box cover adopt a structure of an inner sound-absorbing layer and an outer sound-insulating layer. The box cover is snapped onto the lower box, with openings at both ends for installing an expanded cavity air induced silencer and an expanded cavity air outlet silencer, and an input line interface is provided on the lower box.

[0008] Furthermore, a mounting hole is provided inside the lower box body at a position corresponding to the local fan mounting base, and a mounting base is provided outside the lower box body.

[0009] Furthermore, the expanded cavity induced draft silencer includes an outer shell having a hollow inner cavity and openings at both ends, and a sound-absorbing layer installed in the hollow inner cavity of the outer shell. The outer shell is an outer-insulated and inner-sound-absorbing structure. The expanded cavity induced draft silencer is divided into a connecting section, a flaring section and a silencer section that are connected in sequence, wherein the end of the connecting section is connected to the local fan air inlet through a flange, the flaring section is a frustum or a prism, and an air guide plate is arranged inside to guide the wind into the silencer section. The sound-absorbing layer arranged in the silencer section is correspondingly connected to the air guide plate, and the different sound-absorbing layers and the sound-absorbing layer and the outer shell are connected by support plates.

[0010] Furthermore, a sound absorbing structure is provided on the portion of the support plate within the sound-absorbing section, and the end portion of the support plate located at the air inlet is a triangle with edges facing outward.

[0011] Furthermore, the air guide plate is connected to the inner guard plate of the corresponding sound absorbing layer close to the central axis of the inner cavity of the outer shell, and the outer guard plate and the inner guard plate of the sound absorbing layer frame are filled with sound absorbing material.

[0012] Furthermore, the sound-absorbing layer is provided with an air inlet end with a right-angled triangle cross-section at each end, with the right-angled sides of the two right-angled triangles representing the inner and outer guard plate edges, respectively. This structural design allows the sound-absorbing material to absorb energy more fully, and the structure effectively eliminates eddy currents and reduces noise.

[0013] Furthermore, the sound-absorbing layer located in the innermost layer is a column, and the wind guide plate connected to it is a frustum or a prism, and the lower base of the frustum or prism faces the local fan, and the upper base is connected to one end of the sound-absorbing layer, and the sound-absorbing layer at the connecting end is a frustum or a prism, and the lower base of the frustum or prism is connected to the column.

[0014] Furthermore, the expanded cavity air induction silencer and the expanded cavity air outlet silencer are symmetrically installed with the local fan as the center. The expanded cavity air outlet silencer includes an outer shell having a hollow inner cavity and openings at both ends, and a sound absorbing layer installed in the hollow inner cavity of the outer shell. The outer shell is an outer-insulated and inner-sound absorbing structure. The expanded cavity air outlet silencer is divided into a local fan connecting section, a flaring section, a silencer section, a closing section and a duct connecting section connected in sequence, wherein the end of the local fan connecting section is connected to the local fan outlet through a flange, the flaring section is a frustum or a prism, and an air guide plate is arranged inside to guide the wind into the silencer section, the sound absorbing layer arranged in the silencer section is correspondingly connected to the air guide plate, and different sound absorbing layers and the sound absorbing layer and the outer shell are connected by support plates. The closing section is a frustum or a prism, and an air guide plate is arranged inside to guide the wind from the silencer section to the duct connecting section, and the flaring section and the closing section are symmetrically arranged with the silencer section. It fully solves the vortex of air inlet and outlet, and absorbs sound energy most efficiently to achieve noise reduction.

[0015] The beneficial effects of the present invention are that the cavity expansion air induction silencer, cavity expansion air outlet silencer and box cover are combined to comprehensively control airflow vortex, sound energy, mechanical noise, etc. Without affecting ventilation, it can achieve a 40dB absorption volume, so that the sound can be reduced to a minimum of 70dB, which fully meets the national standard requirement of below 85dB. People working here will not be affected by normal conversation and communication, which improves the comfort of the working environment of the staff. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 This is a schematic structural diagram of the air inlet side of the expanded cavity air induced silencer of the present invention.

[0019] In the figure: 1. local fan, 11. local fan air inlet, 12. local fan air outlet, 2. box cover, 21. lower box, 22. box upper cover, 3. expansion cavity air induced silencer, 31. air induced inlet, 32. outer shell, 33. connecting section, 34. expansion section, 35. silencer section, 4. expansion cavity air outlet silencer, 41. air outlet end, 5. sound absorbing layer, 6. support plate, 7. air guide plate. DETAILED DESCRIPTION

[0020] Example 1

[0021] like Figure 1 As shown, a counter-rotating local fan silencer system includes a box cover 2 in which a local fan 1 is placed, an expansion cavity induced air silencer 3 installed at the local fan air inlet 11, and an expansion cavity outlet air silencer 4 installed at the local fan air outlet 12. The radius of the induced air inlet 31 of the expansion cavity induced air silencer 3 is greater than the radius of the connection end with the local fan air inlet 11, and the radius of the outlet end 41 of the expansion cavity outlet silencer is equal to the radius of the connection end with the local fan air outlet 12. A sound absorbing layer 5 is provided on the inner wall and inner cavity of the shell of the expansion cavity induced air silencer 3 and the expansion cavity outlet air silencer 4.

[0022] The distance between different sound-absorbing layers is proportional to their thickness. The fabrication of sound-absorbing layers isn't arbitrary; their thickness and length are related to the amount of sound absorbed. However, we understand that installation space for local fans is limited, and we can't make the sound-absorbing layers infinitely longer or thicker. Furthermore, ventilation volume must be considered. Therefore, our research has shown that maintaining the distance between adjacent sound-absorbing layers ensures ventilation volume. To achieve optimal sound absorption while maintaining ventilation volume, the thickness of the sound-absorbing layer must be proportional to the volume.

[0023] The enclosure 2 is a sound-absorbing and sound-insulating enclosure, consisting of a lower enclosure 21 and an upper cover 22. Both the lower enclosure 21 and the upper cover 22 feature an inner sound-absorbing layer and an outer sound-insulating layer. The upper cover 22 snaps onto the lower enclosure 21, with openings at both ends for the expansion chamber induction muffler 3 and the expansion chamber outlet muffler 4. The lower enclosure 21 is provided with an inlet cable connection. Mounting holes are provided inside the lower enclosure 21 corresponding to the mounting base of the local fan 1, and a mounting base is provided on the outside. The enclosure 2 is designed to minimize mechanical noise from the local fan.

[0024] It should be noted that in our initial design, we thought that simply adding sound-absorbing and sound-isolating silencers to both sides of the local fan would be sufficient. However, in practice, we found that the sound-absorbing effect was very poor, with a maximum noise level of no more than 10dB. After research, we discovered that the problem was that the wind speed of the local fan was extremely high, and the wind blew over the surface of the silencer, with very little energy loss. We then redirected the wind by installing a wind deflector at the outlet end of the silencer, changing the direction of the wind so that it no longer flowed straight in and out. This allowed the wind to fully dissipate energy in the silencer and reduced the outlet wind speed. However, this solution was not accepted by the customer, who did not want the ventilation performance of the local fan to be excessively affected. Therefore, we designed an expanded-diameter silencer structure at both the inlet and outlet, which did not significantly affect the air inlet and outlet while achieving good sound-absorbing effects.

[0025] According to this embodiment, the manufactured device can reduce noise to below 85dB, meeting the national standard requirements.

[0026] Example 2

[0027] As a preferred design of Example 1, the expanded cavity induced draft silencer 3 includes an outer shell 32 with a hollow inner cavity and openings at both ends, and a sound absorbing layer 5 installed in the hollow inner cavity of the outer shell 32. The outer shell 32 is an outer-insulated and inner-sound absorbing structure. The expanded cavity induced draft silencer 3 is divided into a connecting section 33, a flared section 34 and a silencer section 35 connected in sequence, wherein the end of the connecting section 33 is connected to the local fan air inlet 11 through a flange, the flared section 34 is a frustum or a prism, and an air guide plate 7 is arranged inside to guide the wind into the silencer section 35. The sound absorbing layer 5 arranged in the silencer section 35 is correspondingly connected to the air guide plate 7, and the different sound absorbing layers 5 and the sound absorbing layer 5 and the outer shell 32 are connected by a support plate 6.

[0028] The portion of the support plate 6 within the sound-absorbing section is designed with a sound-absorbing structure. The end of the support plate 6 located at the air inlet 31 is a triangular shape with outward-facing edges. The middle portion of the support plate shares the same structure as the sound-absorbing layer, with a porous protective plate forming a hollow body filled with sound-absorbing material. The end of the support plate located at the air inlet is designed as a triangular shape to prevent wind from generating eddies there. The support plate serves as a connection and support structure between the different sound-absorbing layers and also helps to reduce air turbulence.

[0029] The expanded cavity induction silencer 3 and the expanded cavity outlet silencer 4 are symmetrically installed with the local fan as the center. The expanded cavity outlet silencer 4 includes an outer shell having a hollow inner cavity and openings at both ends, and a sound-absorbing layer installed in the hollow inner cavity of the outer shell. The outer shell is an outer-insulated inner sound-absorbing structure. The expanded cavity outlet silencer is divided into a local fan connecting section, an expansion section, a silencer section, a closing section, and a duct connecting section, which are connected in sequence. The end of the local fan connecting section is connected to the local fan outlet via a flange. The expansion section is a truncated cone or a prism with an internal wind guide plate to guide air into the silencer section. The sound-absorbing layer provided in the silencer section is correspondingly connected to the wind guide plate. The different sound-absorbing layers and the sound-absorbing layer and the outer shell are connected by support plates. The closing section is a truncated cone or a prism with an internal wind guide plate to guide the wind from the silencer section to the duct connecting section. The expansion section and the closing section are symmetrically arranged with the silencer section. This fully solves the vortex of the incoming and outgoing air and absorbs sound energy most efficiently to achieve noise reduction.

[0030] like Figure 2 As shown, in this embodiment, the connecting section, the flared section and the silencer section are made into a connection structure of a cylinder, a truncated cone and a cylinder, and the radius of the silencer section is larger than the radius of the connecting end. A three-layer cylindrical sound-absorbing layer 5 is made, and the support plate 6 and the sound-absorbing layer 5 form a sound-absorbing fan surface, which effectively absorbs sound waves in contact.

[0031] The air guide plate 7 is connected to the inner protective plate of the corresponding sound absorbing layer 5 close to the central axis of the inner cavity of the outer shell, and the outer protective plate and the inner protective plate of the sound absorbing layer frame are filled with sound absorbing material.

[0032] The sound-absorbing layer 5 is provided with an air inlet end with a right-angled triangle cross section at each end, and the right-angled sides of the two right-angled triangles are the inner and outer guard plate edges respectively. This structural design allows the sound-absorbing material to absorb energy more fully, and the structure can effectively eliminate eddy currents and reduce noise.

[0033] The sound-absorbing layer 5 located in the innermost layer is a column, and the wind guide plate connected to it is a frustum or a prism, and the lower bottom surface of the frustum or prism faces the local fan, and the upper bottom surface is connected to one end of the sound-absorbing layer, and the sound-absorbing layer at the connection end is a frustum or a prism, and the lower bottom surface of the frustum or prism is connected to the column.

[0034] The optimized design of this embodiment achieves a 40dB absorption volume, reducing the sound level to a minimum of 70dB. This demonstrates the significant noise reduction benefits of the aforementioned structural design. The present invention integrates a cavity-expanding induction muffler, a cavity-expanding outlet muffler, and a housing cover to comprehensively manage airflow vortexes, acoustic energy, and mechanical noise. This fully meets the national standard of 85dB or less without compromising ventilation, ensuring that workers can work without interrupting conversation and communication, thereby enhancing their work environment comfort.

[0035] Although the above describes and illustrates the specific embodiments of the present invention in detail, it should be pointed out that we can make various equivalent changes and modifications to the above embodiments based on the concept of the present invention. As long as the functional effects produced do not exceed the spirit covered by the specification, they should all be within the scope of protection of the present invention.

Claims

1. A counter-rotating local fan silencing system, comprising a housing housing the local fan, characterized in that: The air duct is provided with an expansion cavity induced draft muffler installed at the air inlet of the local fan and an expansion cavity outlet wind muffler installed at the air outlet of the local fan. The radius of the air duct inlet of the expansion cavity induced draft muffler is greater than the radius of the end connected to the air inlet of the local fan, and the radius of the air outlet end of the expansion cavity outlet wind muffler is equal to the radius of the end connected to the air outlet of the local fan. A sound absorbing layer is provided in the inner wall and inner cavity of the shell of the expansion cavity induced draft muffler and the expansion cavity outlet wind muffler. The expansion cavity induced draft muffler includes an outer shell with a hollow inner cavity and openings at both ends, and a sound absorbing layer installed in the hollow inner cavity of the outer shell. The outer shell is an outer-insulated inner sound absorbing structure. The expansion cavity induced draft muffler has an outer-insulated inner sound absorbing structure. The wind silencer is divided into an induced draft connection section, an induced draft expansion section and an induced draft silencer section which are connected in sequence, wherein the end of the induced draft connection section is connected to the local fan air inlet through a flange, the induced draft expansion section is a truncated cone or a prism, an air guide plate is arranged inside the induced draft expansion section to guide the wind into the induced draft silencer section, the sound absorption layer arranged in the induced draft silencer section is connected to the air guide plate correspondingly, and the different sound absorption layers, as well as the sound absorption layer and the outer shell are connected by a support plate; the box cover is a sound-absorbing and sound-insulating box, which has a lower box and a box cover, and the lower box and the box cover both adopt a structure of an inner sound absorption layer and an outer sound insulation layer, and the box cover The cover is snap-fitted to the lower box body, and openings for the installation of the expanded cavity induced air silencer and the expanded cavity outlet air silencer are reserved at both ends of the box body cover, and an inlet interface is provided on the lower box body; the expanded cavity induced air silencer and the expanded cavity outlet air silencer are symmetrically installed with the local fan as the center, and the expanded cavity outlet air silencer includes an outer shell having a hollow inner cavity and openings at both ends, and a sound absorbing layer installed in the hollow inner cavity of the outer shell body, and the outer shell body is an outer-insulated inner sound absorbing structure, and the expanded cavity outlet air silencer is divided into an outlet connecting section, an outlet expansion section, an outlet silencer section, a closing section and a duct connecting section connected in sequence, wherein the end of the outlet connecting section is connected by a method The flange is connected to the local fan outlet, the outlet expansion section is a frustum or a prism, and an air guide plate is arranged inside the outlet expansion section to guide the wind into the outlet silencer section. The sound absorption layer arranged in the outlet silencer section is correspondingly connected to the air guide plate, and the different sound absorption layers, as well as the sound absorption layer and the outer shell are connected by a support plate. The closing section is a frustum or a prism, and an air guide plate is arranged inside the closing section to guide the wind from the outlet silencer section into the wind duct connecting section. The outlet expansion section and the closing section are symmetrically arranged with the outlet silencer section, and the air guide plate arranged in the outlet expansion section and the air guide plate arranged in the closing section are symmetrically arranged with the outlet silencer section.

2. The counter-rotating local fan silencing system according to claim 1, characterized in that: The lower box body is provided with a mounting hole at a position corresponding to the local fan mounting base inside, and a mounting base is provided outside.

3. The counter-rotating local fan silencing system according to claim 1, characterized in that: The portion of the support plate within the sound-absorbing section is provided with a sound-absorbing structure, and the end portion of the support plate located at the air inlet is a triangle with edges facing outwards.

4. The counter-rotating local fan silencing system according to claim 1, characterized in that: The wind guide plate is connected to the inner guard plate of the corresponding sound absorbing layer close to the central axis of the inner cavity of the outer shell, and the outer guard plate and the inner guard plate of the sound absorbing layer frame are filled with sound absorbing material.

5. The counter-rotating local fan silencing system according to claim 1, characterized in that: An air induction end with a right-angled triangle cross section is provided at both ends of the sound absorbing layer, and the right-angled sides of the two right-angled triangles are an inner guard plate edge and an outer guard plate edge respectively.

6. The counter-rotating local fan silencing system according to claim 1, characterized in that: The sound absorbing layer located in the innermost layer is a column, and the wind guide plate connected to it is a frustum or a prism, and the lower bottom surface of the frustum or prism faces the local fan, and the upper bottom surface is connected to one end of the sound absorbing layer, and the sound absorbing layer at the connection end is a frustum or a prism, and the lower bottom surface of the frustum or prism is connected to the column.

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