CN111489727A - Silencing sheet - Google Patents
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- CN111489727A CN111489727A CN202010442159.4A CN202010442159A CN111489727A CN 111489727 A CN111489727 A CN 111489727A CN 202010442159 A CN202010442159 A CN 202010442159A CN 111489727 A CN111489727 A CN 111489727A
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- 230000030279 gene silencing Effects 0.000 title claims abstract description 86
- 238000010521 absorption reaction Methods 0.000 claims abstract description 30
- 239000000463 material Substances 0.000 claims abstract description 16
- 230000003584 silencer Effects 0.000 claims description 32
- 238000013016 damping Methods 0.000 claims 2
- 238000001228 spectrum Methods 0.000 abstract description 6
- 239000011358 absorbing material Substances 0.000 description 11
- 230000008030 elimination Effects 0.000 description 9
- 238000003379 elimination reaction Methods 0.000 description 9
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- 238000012986 modification Methods 0.000 description 2
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- 230000001186 cumulative effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000011491 glass wool Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
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- 230000007774 longterm Effects 0.000 description 1
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- 238000005272 metallurgy Methods 0.000 description 1
- 239000011490 mineral wool Substances 0.000 description 1
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- 238000010248 power generation Methods 0.000 description 1
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- 230000001172 regenerating effect Effects 0.000 description 1
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/161—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general in systems with fluid flow
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
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- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
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- Chemical & Material Sciences (AREA)
- Aviation & Aerospace Engineering (AREA)
- Combustion & Propulsion (AREA)
- Fluid Mechanics (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
The invention relates to the technical field of silencing sheets, in particular to a silencing sheet. The noise-reduction sheet includes: the silencing sheet shell is at least partially formed by a perforated plate; the sound absorption material is uniformly filled in the housing of the sound absorption sheet; the shell of the silencing piece is sequentially constructed into a front edge plate, a middle panel and a tapered panel along the airflow direction S, wherein the middle panel and the tapered panel are respectively composed of two types of perforated plates with different perforation rates. According to the silencing sheet provided by the invention, different perforation rates are adopted in the middle panel part and the tapered panel part, so that silencing can be carried out on different frequency spectrum parts of a noise source, and the optimal total silencing quantity under the condition of the same pressure loss is achieved.
Description
Technical Field
The invention relates to the technical field of silencing sheets, in particular to a silencing sheet.
Background
The muffler can block and weaken the transmission of sound waves and allow air flow to pass through, and is an effective tool for noise abatement. The resistive noise-eliminating sheet is widely applied to air conditioners and ventilation systems of civil and industrial buildings and used for preventing the outward radiation propagation of operation noise of air conditioning units, fans, cooling towers, boilers, generator sets and other equipment. The silencing performance of the resistive silencing sheet mainly depends on the factors such as the length, the thickness, the distance, the shape of a silencing channel, the characteristics of a perforated plate, the properties of a sound absorption material and the like of the silencing sheet.
The noise reduction amount can be increased by reducing the sheet pitch or increasing the thickness of the noise reduction sheet, but the flow resistance and the aerodynamic regenerative noise are increased; by lengthening the muffler length, the amount of muffling can be increased, but the cost will be correspondingly increased, and the low-frequency muffling performance will not be significantly changed. In the fields of heavy industry such as thermal power generation, chemical industry, metallurgy and the like, the silencer in single project is huge in dosage, equipment is sensitive to flow resistance after long-term operation, and the flow resistance generated by fluid in the silencer can block the normal flow of the fluid, so that the production efficiency is influenced. Therefore, the noise elimination characteristics and the flow resistance characteristics of the silencer have high requirements, and the noise elimination sheet which is suitable for broadband noise elimination of high-frequency, medium-frequency and low-frequency noise elimination and has low flow resistance characteristics is urgently needed to be provided.
Disclosure of Invention
Therefore, the technical problem to be solved by the present invention is to overcome the defect of the prior art that a muffler having both broadband noise elimination and low flow resistance is absent, so as to provide a noise elimination sheet having both broadband noise elimination and low flow resistance.
In order to solve the above technical problem, the present invention provides an anechoic sheet, including:
the silencing sheet shell is at least partially formed by a perforated plate; and
the sound absorption material is uniformly filled in the housing of the sound absorption sheet;
the shell of the silencing piece is sequentially constructed into a front edge plate, a middle panel and a tapered panel along the airflow direction S, wherein the middle panel and the tapered panel are respectively composed of two types of perforated plates with different perforation rates.
Further, the perforation rate of the middle panel is greater than the perforation rate of the tapered panel.
Further, the tapered panel has a trapezoidal or conical or arc-shaped cross section in the width direction, and the small end of the trapezoidal or conical shape is located at the front end position in the airflow flowing direction.
Further, the leading edge plate has a cross-sectional form in the width direction of a semicircle or a semi-ellipse or a cone.
Further, the cross-sectional form of the middle panel in the width direction is rectangular or square.
Further, the tapered angle of the tapered panel along the width direction is 1.5 DEG- α DEG-10 deg.
Further, the tapered panel has a taper angle α of 3.5 ° in the width direction.
Further, the perforation rate of the middle panel is greater than 20%.
Further, the tapered panel has a perforation rate of less than 0.5%.
The technical scheme of the invention has the following advantages:
1. according to the silencing sheet provided by the invention, different perforation rates are adopted in the middle panel part and the tapered panel part, so that silencing can be carried out on different frequency spectrum parts of a noise source, and the optimal total silencing quantity under the condition of the same pressure loss is achieved.
2. According to the silencing sheet provided by the invention, the perforated plate with the large perforation rate is adopted on the middle panel, so that middle-high frequency sound absorption is facilitated, and middle-high frequency sound waves can enter the internal sound absorption material through the perforated plate with the large perforation rate and can be absorbed. Through the perforated plate that adopts little perforation rate at the convergent panel, be favorable to the low frequency sound absorption, the perforated plate entering inside sound absorbing material of the low frequency sound wave of being convenient for through little perforation rate is absorbed.
3. The muffling sheet provided by the invention has the advantages that the tapered panel part is wide firstly and then narrow, a divergent flow channel can be formed between the two muffling sheets which are matched with each other, airflow of two adjacent flow channels is guided to be combined together stably, kinetic energy is recovered to pressure energy to the maximum extent, and flow loss is reduced.
4. According to the silencing sheet provided by the invention, the front edge plate part is narrow first and then wide along the airflow direction S, so that airflow can be stably separated, and the flow guiding effect is realized.
5. According to the silencing sheet provided by the invention, the middle panel part is a parallel plate, so that a straight flow channel can be formed between the two silencing sheets which are matched with each other for use, and the stable passing of airflow is ensured.
6. The silencing pieces provided by the invention ensure that the divergent flow passage is formed between the two silencing pieces which are matched with each other by adopting a smaller contraction angle, so that serious flow separation does not occur in the divergent flow passage section, and the flow loss is reduced.
7. The perforated plate of the silencing sheet provided by the invention adopts two perforation rates, the perforation rate of the perforated plate at the middle panel part is more than 20%, and the cooperation of the perforated plate and the internal sound absorption material plays a main role in medium-high frequency sound absorption, so that sound waves can enter the internal sound absorption material, and the purpose of high-frequency sound absorption is achieved; the panel part of the convergent panel at the rear part of the silencing piece adopts a small-perforation-rate perforated plate, the perforation rate is less than 0.5%, and the perforated plate and the internal sound-absorbing material are matched to play a main role in low-frequency sound absorption, so that sound waves can enter the internal sound-absorbing material, and the low-frequency sound absorption effect is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic structural diagram of a housing of an anti-noise sheet according to the present invention;
FIG. 2 is a schematic structural diagram of the silencing sheet of the present invention;
FIG. 3 is a schematic view of the muffler structure of the present invention;
FIG. 4 is a schematic cross-sectional view of a muffler of the present invention;
FIG. 5 is a schematic diagram of a cross-sectional configuration of a reference muffler;
fig. 6 is a cumulative energy spectrum of noise energy integrated with frequency after being silenced.
Description of reference numerals:
1-silencer outer shell, 2-silencing piece outer shell, 21-front edge plate, 22-middle panel, 23-tapered panel and 3-sound absorption material.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example one
Referring to fig. 1 and 2, an acoustic sheet includes:
a sound-deadening sheet housing 2 at least partially formed of a perforated plate; and
the sound absorption material 3 is uniformly filled in the housing 2 of the sound absorption sheet, and is made of loose porous materials, such as slag wool, sponge and the like, and is not limited too much in the embodiment;
the housing 2 of the noise reduction sheet is sequentially constructed into a front edge plate 21, a middle panel 22 and a tapered panel 23 along an airflow direction S, wherein the middle panel 22 and the tapered panel 23 are respectively composed of two types of perforated plates with different perforation rates, and specifically, the front edge plate 21, the middle panel 22 and the tapered panel 23 are made of metal or hard plastic. Meanwhile, in order to achieve the entry of sound waves into the interior of the sound-deadening sheet, the sound waves enter the sound-absorbing material 3 through the perforations of the perforated plate.
According to the silencing sheet provided by the invention, different perforation rates are adopted in the middle panel part and the tapered panel part, so that silencing can be carried out on different frequency spectrum parts of a noise source, and the optimal total silencing quantity under the condition of the same pressure loss is achieved.
Through adopting the housing of the silencing sheet as the protective surface of the sound absorption material, the structural integrity of the sound absorption material is ensured, and the structural strength is increased.
The perforation rate is a ratio of the sum of perforation areas to the total area of the sheet material.
In particular, the perforation rate of the central panel 22 is greater than the perforation rate of the tapered panel 23. By using a perforated plate with a large perforation rate in the middle panel 22, the sound absorption at medium and high frequencies is facilitated, and the sound waves at medium and high frequencies can be absorbed by entering the internal sound absorbing material through the perforated plate with a large perforation rate. By using a perforated plate with a small perforation rate in the tapered panel 23, low frequency sound absorption is facilitated, and low frequency sound waves are conveniently absorbed by entering the internal sound absorbing material through the perforated plate with a small perforation rate.
Specifically, the sound-absorbing sheet housing 2 is sequentially configured as a front edge plate 21, a middle panel 22 and a tapered panel 23 along the airflow direction S, wherein a first end of the front edge plate 21 is a windward side, as shown in fig. 1, the front edge plate 21 extends from the first end to a second end, and is configured in a structural form with gradually increasing thickness; the first end of the middle panel 22 is connected with the second end of the front edge plate 21, the middle panel 22 extends from the first end to the second end and is configured into a square structure with uniform thickness; the tapered panel 23 is joined at a first end to the second end of the central panel 22 and tapers in thickness from the first end of the tapered panel 23 to the second end of the tapered panel 23.
Specifically, the cross-sectional form of the leading edge plate 21 in the width direction is a semicircle or a semi-ellipse or a cone; the cross section of the middle panel 22 along the width direction is rectangular or square; the tapered panel 23 has a trapezoidal or conical or arc cross section in the width direction, and the small end of the trapezoidal or conical shape is located at the front end in the airflow direction.
According to the shell structure of the silencing sheet, the front edge plate 21 is narrow and wide along the airflow direction S, so that airflow can be stably separated, and the flow guiding effect is achieved; the middle panel 22 is a parallel plate, so that a straight flow channel can be formed between two silencing sheets which are matched with each other for use, and the stable passing of airflow is ensured; the rear tapered panel 23 is wider and narrower, so that a divergent flow channel is formed between the two silencing sheets which are matched with each other, the air flows of the two adjacent flow channels are guided to be combined together stably, the kinetic energy is recovered to pressure energy to the maximum extent, and the flow loss is reduced. The structural shape of the silencing sheet can ensure that a silencer with a straight flow channel and a divergent flow channel formed by placing a plurality of silencing sheets in parallel has smaller total flow resistance and low flow resistance; the thickness of the straight part of the silencing sheet can be increased, the total volume of the silencing sheet can be increased, and the silencing capacity can be enhanced under the condition that the flow resistance is not increased.
In this embodiment, the front edge plate 21 and the middle panel 22, and the middle panel 22 and the tapered panel 23 are fixedly connected, and the specific fixing manner is not limited, and when a plastic material is used, the plastic material may be connected by glue; when made of metal materials, the metal materials can be connected in a welding mode. Meanwhile, the surface of the front edge plate 21 opposite to the middle panel 22 and the surface of the middle panel 22 opposite to the tapered panel 23 can be complete planes, and parts of the surfaces can also be arranged in a hollow manner.
Specifically, as shown in FIG. 4, the tapered panel 23 has a taper angle of 1.5 DEG- α DEG-10 DEG in the width direction.
Specifically, the tapered panel 23 has a taper angle α of 3.5 ° in the width direction.
By adopting a smaller contraction angle, a divergent flow channel is formed between the two silencing sheets which are matched with each other for use, so that serious flow separation does not occur in the divergent flow channel section, and the flow loss is reduced.
As a specific implementation form, the angle numerical value of the taper angle is optimally designed according to the requirement of flow parameters, and the pressure loss of the silencer is guaranteed not to exceed an allowable value.
Specifically, the perforation rate of the central panel 22 is greater than 20%.
Specifically, the tapered panel 23 has a perforation rate of less than 0.5%.
The perforated plate of the silencing sheet has two perforation rates, the perforation rate of the perforated plate at the middle panel part is more than 20%, and the cooperation of the perforated plate and the internal sound absorption material plays a main role in medium-high frequency sound absorption, so that sound waves can enter the internal sound absorption material, and the aim of high-frequency sound absorption is fulfilled;
the panel part of the convergent panel at the rear part of the silencing piece adopts a small-perforation-rate perforated plate, the perforation rate is less than 0.5%, and the perforated plate and the internal sound-absorbing material are matched to play a main role in low-frequency sound absorption, so that sound waves can enter the internal sound-absorbing material, and the low-frequency sound absorption effect is improved.
In addition, the straight flow channel part between the two silencing pieces which are matched with each other is narrower, which is beneficial to high-frequency silencing, and the gradually-expanded flow channel part is narrower and wider firstly, which is beneficial to medium-low frequency silencing, thereby achieving the purpose of broadband silencing.
As an improved implementation form, under specific working conditions, the length proportion of the two perforated plates with the perforation rates can be adjusted according to the high-frequency and low-frequency noise energy proportion of a noise source, and the optimal total noise elimination effect is achieved. If the high-frequency noise ratio in the noise source is large, the length of the perforated plate with the large perforation rate is increased; when the noise source has a large low frequency noise ratio, the length of the small-perforation-rate perforated plate is increased, and the small-perforation-rate perforated plate of the tapered panel may be extended to the middle panel portion as necessary.
As an improved implementation form, under specific working conditions, the length ratio of the perforated plates with large perforation rates and small perforation rates can be adjusted according to the energy ratio of high-frequency noise and low-frequency noise in a noise source, and the design of more than two perforation rates can be selected according to requirements so as to achieve the optimal broadband noise elimination effect.
Example two
Referring to fig. 3, a plate muffler includes at least one muffling plate as described above, and further includes:
the silencer comprises a silencer outer shell 1, wherein the silencer outer shell 1 is suitable for containing at least two silencing sheets at intervals, and an airflow channel is formed between the two silencing sheets.
As an improved implementation form, at least two of the silencing sheets are placed in parallel with each other.
As a further improved implementation form, at least two of the silencing sheets are arranged in parallel and at equal intervals. The straight flow channel at the front part and the divergent flow channel at the rear part of the silencer are constructed by combining the specific structural form of the silencing sheet and arranging the silencing sheet in parallel at equal intervals.
The middle panel 22 is a parallel plate, so that a straight flow channel can be formed between two silencing sheets which are matched with each other for use, and the stable passing of airflow is ensured; the rear tapered panel 23 is wider and narrower, so that a divergent flow channel is formed between the two silencing sheets which are matched with each other, the air flows of the two adjacent flow channels are guided to be combined together stably, the kinetic energy is recovered to pressure energy to the maximum extent, and the flow loss is reduced. The structural shape of the silencing sheet can ensure that a silencer with a straight flow channel and a divergent flow channel formed by placing a plurality of silencing sheets in parallel has smaller total flow resistance and low flow resistance; the thickness of the straight part of the silencing sheet can be increased, the total volume of the silencing sheet can be increased, and the silencing capacity can be enhanced under the condition that the flow resistance is not increased. In addition, the straight flow channel part between the two silencing pieces which are matched with each other is narrower, which is beneficial to high-frequency silencing, and the gradually-expanded flow channel part is narrower and wider firstly, which is beneficial to medium-low frequency silencing, thereby achieving the purpose of broadband silencing.
The pressure loss of the sheet type silencer provided by the invention is mainly controlled by the channel size of the front straight channel, the pressure loss is small when the channel size is large, and the pressure loss is large when the channel size is small.
As an improved implementation, a balanced relationship between acoustic performance and pressure loss can be achieved by fine tuning the thickness of the middle panel 22 and the channel size of the straight flow channel according to specific engineering design requirements. If the sound-absorbing material of the middle panel 22 is thin, the pressure loss is low, and the relative noise reduction is also reduced, whereas if the sound-absorbing material of the middle panel 22 is thick, the pressure loss is large, and the noise reduction is increased; by balancing the thickness of the middle panel 22 and the channel size of the straight flow path, the best product integration is achieved.
EXAMPLE III
In order to prove that the silencing sheet and the corresponding sheet type silencer provided by the invention have better silencing effect compared with the traditional silencing structure, the details are described in the following through comparison experiments.
For convenience, the silencing sheet provided by the invention is referred to as the silencing sheet, and the sheet type silencer provided by the invention is referred to as the silencer.
In comparison with fig. 5, the noise reduction sheet without the tapered panel is defined as a reference noise reduction sheet, and a noise reducer corresponding to the reference noise reduction sheet and having a uniform passage in the front and rear directions of the airflow direction S and a given pressure loss is defined as a reference noise reducer. When the silencer is designed, the thickness of the parallel part of the silencing sheet is larger than that of the reference silencing sheet, and the total volume of the silencing sheet is larger than that of the reference silencing sheet, so that the total silencing quantity of the silencer is larger than that of the reference silencer. The silencer adopts a divergent flow passage and the front edge plate flow guide design of the silencing sheet, so that the pressure loss of the silencer is smaller than that of a reference silencer under the conditions of narrowing of a straight part and the like.
The following will specifically explain the experimental effect of the present muffler by comparing the performance of the present muffler with that of a reference muffler and comparing the flow resistance performance, the wide-band muffling performance, and the low-frequency muffling performance with each other, as shown in fig. 4 and 5.
The total length of the silencing sheet is L, the length of the middle panel of the silencing sheet is L1, the width of the middle panel of the silencing sheet is h, the length of the tapered panel is L2, the distance between two adjacent silencing sheets is b, the tapered angle of the tapered panel along the width direction is α, the total length of the reference silencing sheet is L, the distance between two adjacent silencing sheets is b ', and the width of the middle panel is h ', wherein L is more than 0m, L1 is more than 0m, L2 is more than 0m, b is more than 0m, α is more than 0, b is more than 0m, and h ' is more than 0 m.
The present mufflers 1 and 2, and the reference muffler, with different dimensional parameters, were set, and the specifications of the muffling sheet design of the three mufflers are listed in table 1. The interior of the muffler is filled with the same resistive sound absorbing material, which is glass wool with the volume weight of 24-48kg/m 3.
TABLE 1 silencing sheet design description
Through specific experiments, the test results of the muffling amount of the muffler 1, the muffler 2 and the reference muffler are shown in the following table 2.
TABLE 2 insertion loss test results (dBA) for this muffler 1, this muffler 2 and the reference muffler
Note: the reference silencer and the silencer 1 test the wind speed at 5.1m/s, and the silencer 2 tests the wind speed at 5 m/s.
The results of the three muffler flow resistance measurements are shown in table 3 below.
TABLE 3 pressure loss test results of the present muffler 1, the present muffler 2 and the reference muffler
| Wind speed (m/s) | Reference muffler | The muffler 1 | The |
| 5.1 | 35.9 | 24.6 | 36.5 |
| 6.6 | 62.1 | 45.6 | 59.7 |
| 8.1 | 93.8 | 67.3 | 91.2 |
Note: the test wind speeds of the silencer 2 are 5m/s, 6.5m/s and 8m/s respectively.
It can be seen from the combination of tables 2 and 3 that the flow resistance of the muffler 1 is significantly reduced, which is about 29% lower on average, and the muffling amount is slightly increased (2.23dB) compared with the reference muffler. Compared with a reference silencer, the silencer 2 has the advantages that the silencing volume is 6.78dB higher, and the flow resistance of the two silencers is similar.
Meanwhile, the sound attenuation capacity of the silencer 1 and the silencer 2 at low frequency is obviously higher than that of a reference silencer. In order to compare the three muffler effects more intuitively as shown in fig. 6, fig. 6 shows an accumulated energy spectrum of noise energy integrated with frequency after muffling, and the sound source is the noise spectrum of the cooling tower. A0 is a reference muffler, A1 is the muffler 1, and A2 is the muffler 2.
It can be seen that, after the muffler is referred, the noise energy curve 100-200Hz increases rapidly, and the slope is large, which indicates that the noise energy in this frequency band is still large, and the muffler has limited low-frequency sound absorption capability. Compared with the reference muffler, the slope of the mufflers 1 and 2 is obviously reduced relative to the reference muffler, which shows that the low-frequency muffling performance is much better. The silencing performance of the traditional straight silencing sheet is mainly concentrated on the medium frequency, low-frequency noise is always a difficult point of noise reduction, and the sheet type silencer provided by the invention can well solve the problem of low-frequency noise.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (9)
1. An anechoic sheet, comprising:
a housing (2) for the noise-damping sheet, which is at least partially formed by a perforated plate; and
the sound absorption material (3) is uniformly filled in the sound absorption sheet shell (2);
the silencer assembly is characterized in that the silencer housing (2) is sequentially constructed into a front edge plate (21), a middle panel (22) and a tapered panel (23) along the airflow direction S, wherein the middle panel (22) and the tapered panel (23) are respectively composed of two types of perforated plates with different perforation rates.
2. An anechoic sheet according to claim 1, characterized in that the perforation rate of the central panel (22) is greater than the perforation rate of the tapered panel (23).
3. The muffling sheet according to claim 1, wherein the tapered panel (23) has a trapezoidal or conical or arc-shaped cross-sectional form in the width direction, and the small end of the trapezoidal or conical form is located at the front end position in the airflow direction.
4. The noise-canceling sheet according to claim 3, wherein the cross-sectional form of the leading edge plate (21) in the width direction is a semicircle or a semi-ellipse or a cone.
5. The silencing sheet according to claim 4, wherein the cross-sectional form of the central panel (22) in the width direction is rectangular or square.
6. An acoustical damping sheet according to claim 3, wherein the tapered panel (23) has a taper angle of 1.5 ° ≦ α ≦ 10 ° in the width direction.
7. An anechoic sheet according to claim 3, characterised in that the tapering angle α of the tapering panel (23) in the width direction is 3.5 °.
8. An anechoic sheet according to claim 2, characterized in that said central panel (22) has a perforation rate greater than 20%.
9. An anechoic sheet according to claim 2, characterized in that said tapered panel (23) has a perforation rate of less than 0.5%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010442159.4A CN111489727A (en) | 2020-05-22 | 2020-05-22 | Silencing sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010442159.4A CN111489727A (en) | 2020-05-22 | 2020-05-22 | Silencing sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111489727A true CN111489727A (en) | 2020-08-04 |
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| CN202010442159.4A Pending CN111489727A (en) | 2020-05-22 | 2020-05-22 | Silencing sheet |
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Citations (9)
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| CN2516932Y (en) * | 2001-12-12 | 2002-10-16 | 余根林 | Noise reducer of cooling tower |
| CN202835736U (en) * | 2012-10-19 | 2013-03-27 | 中船第九设计研究院工程有限公司 | Plate type silencer with different thickness sound absorbing plates arranged at intervals |
| CN204704012U (en) * | 2015-04-15 | 2015-10-14 | 北京绿创声学工程股份有限公司 | A kind of combustion engine intake grill silencing apparatus |
| CN206340335U (en) * | 2016-11-21 | 2017-07-18 | 北京市劳动保护科学研究所 | A kind of impedance complex formula anechoic sheet |
| CN207634397U (en) * | 2017-09-05 | 2018-07-20 | 上海声望声学科技股份有限公司 | Ventilation silencer |
| RU2671278C1 (en) * | 2017-09-15 | 2018-10-30 | Олег Савельевич Кочетов | Workshop acoustic structure |
| CN109285534A (en) * | 2018-11-06 | 2019-01-29 | 株洲国创轨道科技有限公司 | Sound absorber |
| CN208488970U (en) * | 2018-06-26 | 2019-02-12 | 香港大学浙江科学技术研究院 | Local perforations plate muffling unit, combination perforated plate muffling unit, composite sound damping piece, composite sound damping device and pipe-line system |
| CN212276802U (en) * | 2020-05-22 | 2021-01-01 | 华电重工股份有限公司 | Silencing sheet |
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2020
- 2020-05-22 CN CN202010442159.4A patent/CN111489727A/en active Pending
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| CN2516932Y (en) * | 2001-12-12 | 2002-10-16 | 余根林 | Noise reducer of cooling tower |
| CN202835736U (en) * | 2012-10-19 | 2013-03-27 | 中船第九设计研究院工程有限公司 | Plate type silencer with different thickness sound absorbing plates arranged at intervals |
| CN204704012U (en) * | 2015-04-15 | 2015-10-14 | 北京绿创声学工程股份有限公司 | A kind of combustion engine intake grill silencing apparatus |
| CN206340335U (en) * | 2016-11-21 | 2017-07-18 | 北京市劳动保护科学研究所 | A kind of impedance complex formula anechoic sheet |
| CN207634397U (en) * | 2017-09-05 | 2018-07-20 | 上海声望声学科技股份有限公司 | Ventilation silencer |
| RU2671278C1 (en) * | 2017-09-15 | 2018-10-30 | Олег Савельевич Кочетов | Workshop acoustic structure |
| CN208488970U (en) * | 2018-06-26 | 2019-02-12 | 香港大学浙江科学技术研究院 | Local perforations plate muffling unit, combination perforated plate muffling unit, composite sound damping piece, composite sound damping device and pipe-line system |
| CN109285534A (en) * | 2018-11-06 | 2019-01-29 | 株洲国创轨道科技有限公司 | Sound absorber |
| CN212276802U (en) * | 2020-05-22 | 2021-01-01 | 华电重工股份有限公司 | Silencing sheet |
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