JP4217432B2 - Silencer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silencer, and more particularly, to a passive silencer that is effective against noise in a low frequency band that propagates through, for example, an air supply / exhaust duct that is generated by a blower.
[0002]
[Prior art]
As a silencer for silencing noise propagating through an air passage such as an air conditioning duct, for example, a silencer described in Japanese Patent Application Laid-Open No. 57-119120 is known. This silencer is provided with a spiral partition plate in the gap between the inner cylinder and the outer cylinder, and a part of the fluid flows in the inner cylinder and the remaining part flows while turning the gap in the circumferential direction. It is. This silencer sets the path length by the gap according to the frequency of the sound to be silenced, and attempts to silence the sound to be silenced by causing the sound waves to be silenced to mutually interfere at the junction of the gap and the inner cylinder. To do.
[0003]
As a silencer, for example, a silencer that can open and close an X-type shielding plate described in JP-A-61-38113 is known. This silencer crosses two or more shields and sound absorbing plates alternately at the center, and can be combined in an X shape at a free angle, and can be opened and closed with the shield or one of the sound absorbing plates or the center as a fulcrum. is there. This silencer can freely open and close and change the angle of the X shape, and is intended to mute the sound to be silenced by adjusting to the frequency and volume reduction.
[0004]
As a silencer, for example, a silencer muffler described in JP-A-63-23367 is known. This silencer muffler is a horizontally long, substantially box-shaped muffler body, an exhaust inlet and an exhaust outlet provided concentrically on the lower and upper central parts of the muffler body, and the inside of the muffler body in a horizontal blind plate. A horizontal blind plate that is divided into two upper and lower chambers, a baffle plate that horizontally divides the exhaust gas that is introduced into the lower chamber from the exhaust inlet, and a punching plate and a resonance tube that are appropriately disposed in the chamber. This muffler muffles the exhaust gas from the exhaust pipe to the chamber suddenly, silences the chamber, joins and collides with the exhaust gas from substantially the opposite direction when discharging, and tries to mute the sound to be silenced.
[0005]
The silencer described in Japanese Patent Application Laid-Open No. 57-119120 is excellent in silencing the sound to be silenced, but has a structure in which the path length of the gap is set according to the frequency of the sound to be silenced. In addition, there is a drawback that the frequency band of the sound to be silenced is easily limited to a predetermined range.
[0006]
The silencer described in Japanese Patent Application Laid-Open No. 61-38113 can appropriately set the sound to be silenced by adjusting the angle of the shielding and sound absorbing plates, but it has a structure that can cause deterioration or failure of the rotating part. , Has the disadvantage of requiring maintenance. Further, this silencer has a defect that a gap is formed between the shield and the sound absorbing plate and the main body depending on how the shield and the sound absorbing plate are adjusted, and self-noise is generated by the airflow passing through the gap.
[0007]
The muffler described in Japanese Patent Laid-Open No. 63-23367 is excellent in muffing sounds in a wider frequency band due to expansion and collision of exhaust gas and noise muffling during passage. Since the flow of exhaust is blocked, pressure loss is likely to occur, and there is still room for improvement in suppressing this pressure loss. Further, this muffler muffler has a structure in which an air passage is formed in a direction perpendicular to the flow direction of the exhaust gas so far, and has a drawback that installation locations are easily limited.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described matters, and can mute sounds in a wide frequency band from a low frequency band to a high frequency band, can reduce pressure loss, and can suppress the occurrence of self noise. It is an object to provide a simple silencer.
[0009]
[Means for Solving the Problems]
The present invention utilizes sound absorption by a sound-absorbing material and reflection and interference of sound in a cross-sectional air passage whose cross-sectional area is constant and whose direction and position are continuously changed. The sound of a wide frequency band up to is muted with low pressure loss.
[0010]
That is, the silencer of the present invention has a bent air passage and a sound absorbing material provided facing the air passage, and is a silencer for eliminating noise propagating through the air passage. The cross-sectional area is a continuous part with a constant cross-sectional area, and the cross-sectional shape is changed from a first shape that is a slender shape to a second shape that is a point-symmetric or line-symmetric shape, and a slender shape. The major axis of the first shape and the major axis of the third shape are in a crossing relationship with each other, and the ventilation path passing through the center of symmetry in the second shape. When a straight line extending in the axial direction is used as a reference axis, the center of the major axis of the first shape and the center of the major axis of the third shape are at least a part of the first shape and the third shape. The positional relationship deviates from the reference axis within the range overlapping the second shape.
[0011]
According to the above configuration, the ventilation area in the ventilation path is constant, and the ventilation direction in the ventilation path changes in a range of a gentler angle than the right angle with respect to the ventilation direction before the silencer is introduced. Can be reduced.
[0012]
Moreover, according to the said structure, since the wall surface which inclines at various angles is formed in an air passage, a sound collides easily and it is easy to reflect a sound in various directions and to interfere easily. Further, since the sound absorbing material is provided facing the air passage, the sound that collides with the wall surface is easily absorbed.
[0013]
In the air passage, the cross-sectional area is constant and the cross-sectional shape changes from the elongated first shape to the elongated third shape through the symmetric second shape, and the first and third shapes That the cross-sectional shape changes toward the positional relationship in which the longitudinal directions (longer sides of the elongated shape) cross each other means that the longitudinal direction of the first shape changes from the first shape to the third shape. This means that the cross-sectional shape of the air passage changes in the direction of reduction and the short direction increases. According to such change in the cross-sectional shape of the air passage, the sound propagating through the air passage is It tends to attenuate when the shape expands. The air passage has two directions, a longitudinal direction of the first shape and a longitudinal direction of the third shape, as directions in which the cross-sectional shape expands in accordance with the air flow direction. This is advantageous in terms of damping. Therefore, according to the shape of the air passage as described above, it is possible to mute the sound in a wide frequency band.
[0014]
In addition, according to the above configuration, the cross-sectional area of the air passage is kept constant, and since there is no movable member that is appropriately adjusted at the time of silencing, such as a shielding plate or a reflecting plate, generation of self noise is suppressed. It is possible.
[0015]
The silencer of the present invention has a bent air passage and a sound absorbing material provided facing the air passage. The air passage is a continuous portion with a constant cross-sectional area, and the cross-sectional shape is changed from an elongated first shape to an elongated shape through a second shape that is a point-symmetrical or line-symmetrical shape. It includes a portion that continuously changes to a third shape. Here, “bend” means that the axis of the air passage is bent. Further, “the cross-sectional area is constant” means that all areas of the continuously changing cross-sectional shape are substantially constant. In the present invention, the cross-sectional areas do not have to coincide strictly. The axis of the air passage means a line connecting the centers of the cross-sectional shapes of the air passage.
[0016]
As for the first to third shapes, in the present invention, the major axis of the first shape and the major axis of the third shape are in a positional relationship intersecting each other, and pass through the symmetrical center in the second shape. When a straight line extending in the axial direction of the air passage is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are at least each of the first shape and the third shape. It is in a positional relationship deviating from the reference axis in a range where a part of the second shape overlaps.
[0017]
Here, the “major axis” in the first shape and the third shape refers to the longer line among the lines passing through the central part inside the elongated shape (for example, in the banana shape, the bent ends are connected to form a shape. Is an arcuate line through the center of In addition, the “symmetric center” in the second shape refers to a center of symmetry in point symmetry or a midpoint in the shape of a line symmetry axis of symmetry. The reference axis is a straight line that passes through the center of symmetry and extends in a direction orthogonal to a plane including the second shape.
[0018]
The first shape is an elongated shape and may be symmetric or asymmetric. As a preferable first shape, for example, an elliptical shape, a semicircular shape, a rectangular shape, and the like can be given. The second shape is a point-symmetric or line-symmetric shape. Preferred examples of the second shape include a circle and a square. The third shape is an elongated shape, and may be symmetric or asymmetric. The third shape may be the same shape as the first shape or a different shape. Preferred examples of the third shape include an elliptical shape, a semicircular shape, and a rectangular shape.
[0019]
In addition, although the silencer according to the present invention includes the above-described portion, it may include an appropriate member for forming such a portion in the ventilation path, for example, the first shape or the third shape. A member such as a joint provided adjacent to the shape may be provided.
[0020]
Regarding the positional relationship between the first to third shapes, in the present invention, the first shape and the second shape, and the second shape and the third shape may be in a positional relationship that overlaps at least partially. However, when the first shape and the third shape are in a positional relationship such that they do not overlap each other, it is preferable to increase the number of times the sound collides with the wall surface of the air passage.
[0021]
In addition, as for the positional relationship between the first, second and third shapes, in the continuous cross section constituting the air passage, any two may be in a positional relationship that does not overlap each other. When the cross-sectional shape of the air passage changes continuously from the first shape to the third shape as one unit, and the air passage has n units directly, the sound to the wall surface of the air passage It is preferable to increase the number of collisions, and when all the cross-sectional shapes included in the n units are targeted, it is preferable that at least two cross-sectional shapes have a positional relationship that does not overlap each other.
[0022]
As such a positional relationship, for example, there is a positional relationship in which the first shape of a certain unit and the first shape of another unit do not overlap, the first shape of a certain unit and the second shape of another unit. Positional relationship that does not overlap, positional relationship that the first shape of one unit does not overlap with the third shape of another unit, positional relationship that the second shape of one unit does not overlap with the first shape of another unit A positional relationship in which a second shape in a unit and a second shape in another unit do not overlap, a positional relationship in which a second shape in a unit does not overlap with a third shape in another unit, in a unit Position where the third shape and the first shape of the other unit do not overlap, the position where the third shape of one unit and the second shape of the other unit do not overlap Relationship, a third shape and the positional relationship which does not overlap the third shape and the other units in a unit, and the like.
[0023]
In the present invention, the major axis of the first shape and the major axis of the third shape are orthogonal to each other, and the first shape and the third shape are based on the position of the second shape. As described above, it is preferable to have a positional relationship biased in the direction of overlapping each other in order to form a ventilation path whose cross-sectional shape changes in a complicated manner and to attenuate sound transmitted through the ventilation path.
[0024]
That is, a straight line including at least one point on the outer edge of the second shape is used as one reference line, and a straight line orthogonal to the one reference line and including at least one point on the outer edge of the second shape is the other. And a reference line that extends along the longitudinal direction of the first shape and includes at least one point on the outer edge of the first shape overlaps with one reference line, It is preferable that the straight line that extends along the longitudinal direction of the third shape and includes at least one point on the outer edge of the third shape overlaps with the other reference line.
[0025]
Here, the “straight line including at least one point on the outer edge” indicates either a tangent line or a straight line including one side. That is, when the cross-sectional shape of the air passage is a polygon, it can indicate a straight line including one side or a straight line that touches one corner, and when the cross-sectional shape of the air passage is a non-square shape such as a circle or an ellipse, Show. In addition, when the cross-sectional shape of the air passage includes both a curved line and a straight line such as a semicircular shape, it can be arbitrarily selected from a straight line including one side, a straight line in contact with one corner, and a tangent line.
[0026]
Particularly, in the present invention, the first shape is at a position where the center of the major axis of the first shape is on the other reference line, and the center of the major axis of the third shape is one of the third shape. More preferably, the position is on the reference line. According to such a configuration, when the units are arranged in parallel, the cross sections forming the first shape are adjacent to each other at one end side of the units, and the cross section forming the third shape is formed at the other end side of the unit. They are adjacent to each other, and one end surface and the other end surface of the unit are formed on a coaxial line.
[0027]
In the case of such a unit, in particular, when the first shape and the third shape are rectangular and the second shape is a square, the rectangular duct is easy to manufacture and is widely used for air conditioning and the like. It is preferable when applied to. Furthermore, it is preferable that the first shape and the third shape have a cross-sectional shape that becomes a predetermined duct shape when the first shapes are adjacent to each other. A semi-circle is mentioned.
[0028]
When the two units in the parallel positional relationship are made into one block, in the present invention, the two blocks are connected in series to form a complicatedly bent air passage and to be stored in use. Is preferable, and it is preferable for enhancing the silencing effect.
[0029]
As the connection form of the blocks, it is preferable that two of all the cross-sectional shapes arranged in series in the air passage formed by the connection of the blocks are in a positional relationship such that they do not overlap each other. Depending on the type of block. For example, when connecting blocks having the same structure, it is preferable to connect the blocks so that the first shape and the third shape are combined at the connection portion.
[0030]
In the present invention, from the viewpoint of forming a complicatedly bent air passage, it is particularly preferable to connect two blocks that are mirror images of each other. When connecting such blocks, it is preferable to connect the blocks so that the major axis of the first shape and the major axis of the third shape are orthogonal to each other. Here, the “mirror image relationship” refers to a state in which the relationship between two objects is in the relationship between one object and the image reflected in the mirror.
[0031]
The silencer of the present invention can be made of a known material. In the present invention, the air passage can be constituted by a plate-like member such as an iron plate or a resin-made plate-like member, an integrally molded product made of resin, or the like. The material of the air passage is appropriately selected according to the use conditions of the silencer of the present invention. In the present invention, the air passage is preferably formed of an ultra-high density glass wool plate in order to mute the sound in the low frequency band. Here, “ultra-high density glass wool plate” means that glass wool is pressure-bonded using an adhesive or the like, and the density of the glass is 200 kg / m. ^Three Say something about. The ultra-high density glass wool plate has a glass density about three times that of a normally used glass duct.
[0032]
In the case of forming a ventilation path with an ultra-high density glass wool plate, the thickness of the ultra-high density glass wool plate is preferably about 10 to 15 mm in order to mute the sound in the low frequency band. If the thickness of the ultra-high density glass wool plate is too thin, sound may be transmitted too much to reduce the silencing effect, and the strength of the air passage may be insufficient. On the other hand, if the thickness of the ultra-high density glass wool plate is too thick, the air passage becomes heavy, and it may be difficult to install the silencer.
[0033]
As the sound absorbing material used in the present invention, a known sound absorbing material made of cotton-like fibers such as glass wool and rock wool can be used. In the present invention, the sound absorbing material is preferably glass wool in order to mute the sound in the high frequency band. The sound absorbing material is appropriately selected according to the use conditions of the silencer of the present invention. For example, when the silencer of the present invention is used for an exhaust system of an internal combustion engine, it is preferable to use rock wool having higher heat resistance as a sound absorbing material. In the present invention, the thickness of the sound absorbing material supported on the ventilation side wall surface varies depending on the type of the sound absorbing material, the volume of the sound to be silenced, and the like, but for example, about 25 mm is preferable for glass wool.
[0034]
The sound absorbing material can be supported by adhering to the ventilation side wall surface with an adhesive, for example. In the present invention, it is preferable to use a pressing member that presses the sound absorbing material toward the ventilation side wall surface from the viewpoint of preventing scattering of the sound absorbing material when applied when the ventilation speed in the air passage is high. Examples of such a pressing member include a glass cloth, a filament mat (glass wool plate-shaped product), and a punching plate.
[0035]
Moreover, in this invention, you may use a suitable connection member in the connection of the said unit and the said blocks, and the connection of a silencer and a ventilation system. A connecting member having an appropriate configuration may be used according to the cross-sectional shape and the number of the cross-sectional shapes appearing on the end face of the unit or block, and examples thereof include a flange.
[0036]
Further, in the present invention, the number of air passages is not particularly limited. For example, more air passages may be arranged in any of the series and parallel directions within a range in which an increase in pressure loss and generation of self noise can be suppressed. good.
[0037]
The silencer of the present invention has a low pressure loss, hardly generates self-noise, has an excellent silencing effect, can be reduced in weight, and is excellent in terms of versatility. It is possible to apply to. Therefore, the silencer of the present invention includes, for example, a duct system in which a blower is provided in an air conditioning / ventilation facility, an engine exhaust pipe system (smoke) of a generator, a machine tool, a construction vehicle, etc. It can be applied to various ventilation systems such as a parking lot, a supply / exhaust duct for a subway, etc.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the silencer in the present embodiment includes a block 1, a block 2 connected in series to the block 1, a flange 3, and a flange 4. The block 1 is composed of a unit 1A and a unit 1B, and the block 2 is composed of a unit 2A and a unit 2B. A flange 3 is connected to one end side of the block 1. One end side of the block 2 is connected to the other end side of the block 1. A flange 4 is connected to the other end of the block 2. The block 1 and the block 2 are mirror images of each other, that is, two blocks are in the relationship between one block and the image reflected in the mirror, and are blocks having the same structure except for such a mirror image relationship. is there.
[0039]
As shown in FIGS. 2 and 3, the block 1 has a rectangular opening in each unit vertically aligned on one end side to form a square shape, and a rectangular opening in each unit horizontally on the other end side. A square shape is formed in parallel. The hatched portion shown in FIG. 2 is a portion that can be seen through when the block 1 is viewed from the arrow X direction. The portion that appears to penetrate through the block 1 includes a straight line that bisects the end surface of the block 1 in the vertical direction as a reference line B11, and a straight line that bisects the end surface of the block 1 in the horizontal direction perpendicular to the reference line B11 In this case, the end surfaces of the block 1 divided into four by these straight lines are formed in the upper left and lower right regions with respect to the paper surface in FIG.
[0040]
As shown in FIG. 4 and FIG. 5, the block 2 has a rectangular opening in each unit vertically arranged on one end side to form a square shape, and a rectangular opening on each unit horizontally on the other end side. A square shape is formed in parallel. The hatched portion shown in FIG. 4 is a portion that can be seen through when the block 2 is viewed from the arrow X direction. The portion that appears to penetrate through the block 2 is formed in the lower left and upper right areas of the end face of the block 2 that is divided into four by the reference line B11 and the reference line B12 with respect to the paper surface in FIG.
[0041]
The block 1 is composed of a unit 1A and a unit 1B parallel to the unit 1A. The unit 1B is obtained by rotating the unit 1A by 180 ° about the intersection of the reference line B11 and the reference line B12 and having the same structure.
[0042]
Similarly, the block 2 includes a unit 2A and a unit 2B parallel to the unit 2A. The unit 2B is obtained by rotating the unit 2A by 180 ° about the intersection of the reference line B11 and the reference line B12 and having the same structure.
[0043]
As shown in FIGS. 6 and 7, the unit 1 </ b> A, when viewed from the direction of the arrow X in FIG. 1, passes from a vertically long rectangle A that is the first shape to a square B that is the second shape, to the third shape. The cross-sectional shape continuously changes to a horizontally long rectangle C which is a shape. The rectangle A, the square B, and the rectangle C have substantially the same area, the rectangle A and the rectangle C have the same size, and the ratio of the long side to the short side is about 2: 1.
[0044]
As shown in FIG. 6, when viewed from the direction of arrow X in FIG. 1, the rectangle A has one long side overlapped with the reference line B11, and the center C11 of the long axis of the rectangle A is on the reference line B12. In a certain position. The square B is in a position where one side overlaps the reference line B11 and the other side adjacent to the one side overlaps the reference line B12. In the rectangle C, one long side overlaps the reference line B12, and the center C13 of the long axis of the rectangle C is located on the reference line B11. Note that the hatched portion in FIG. 6 indicates the portion that can be seen through in the unit 1A.
[0045]
Further, as shown in FIG. 7, when viewed from the direction of the arrow Y in FIG. 1, when a straight line passing through the symmetrical center C12 of the square B and perpendicular to the plane including the square B is the reference axis Ba1, the rectangle A The center C11 of the middle axis and the center C13 of the long axis of the rectangle C are in a positional relationship deviating from the reference axis Ba1.
[0046]
That is, the unit 1A has a wall surface including the reference line B11 and a plane including the reference line B12 as a wall surface, and is rectangular with respect to the paper surface in FIG. While moving upward from A, the height is reduced and expanded to the left to reach the square B. With reference to the wall surface including the reference line B12, the height is expanded while moving from the square B to the right and reduced downward. Thus, a cross-sectional air passage reaching the rectangle C is formed by the wall surface of the air passage.
[0047]
Similarly, as shown in FIGS. 8 and 9, the unit 2 </ b> A, when viewed from the direction of the arrow X in FIG. 1, passes from a vertically long rectangle A that is the first shape to a square B that is the second shape. The cross-sectional shape continuously changes to a horizontally long rectangle C which is a third shape. The rectangle A, the square B, and the rectangle C have substantially the same area, the rectangle A and the rectangle C have the same size, and the ratio of the long side to the short side is about 2: 1.
[0048]
As shown in FIG. 8, when viewed from the direction of the arrow X in FIG. 1, the rectangle A has one long side overlapping the reference line Bl1, and the long axis center C21 of the rectangle A is on the reference line B12. In a certain position. The square B is in a position where one side overlaps the reference line B11 and the other side adjacent to the one side overlaps the reference line B12. In the rectangle C, one long side overlaps with the reference line B12, and the center C23 of the long axis of the rectangle C is on the reference line B11. In addition, the shaded portion in FIG. 8 indicates the portion that can be seen through in the unit 2A.
[0049]
As shown in FIG. 9, when viewed from the direction of arrow Y in FIG. 1, when a straight line passing through the symmetrical center C22 of the square B and perpendicular to the plane including the square B is the reference axis Ba2, the rectangle A The center C21 of the middle axis and the center C23 of the long axis of the rectangle C are in a positional relationship deviating from the reference axis Ba2.
[0050]
That is, the unit 2A has a wall surface including the reference line B11 and a plane including the reference line B12 as a wall surface, and is rectangular with respect to the paper surface in FIG. 8 when the wall surface including the reference line B11 is used as a reference. Reduced from A to the lower side and expanded to the left to expand to the square B, with the wall surface including the reference line B12 as a reference, expanded from the square B to the right and expanded to the upper side to reduce the rectangle C An air passage having a cross-sectional shape extending to the center is formed by the wall surface of the air passage.
[0051]
The unit 1A is composed of segments shown in FIGS. This segment is composed of an ultra-high-density glass wool plate formed in the shape of each surface of ad surfaces, and glass wool, which is a sound-absorbing material attached to the ultra-high-density glass wool plate. A rectangle formed on one end face of the segment is a rectangle A or a rectangle C (FIG. 10), and a square formed on the other end face of the segment is a square B (FIG. 11). The unit 1A is configured by connecting the two segments so that the b-plane and d-plane and the a-plane and c-plane of the segments are adjacent to each other.
[0052]
Similarly, the unit 2A is composed of segments shown in FIGS. This segment is composed of an ultra-high-density glass wool plate formed in the shape of each surface of ad surfaces, and glass wool, which is a sound-absorbing material attached to the ultra-high-density glass wool plate. A rectangle formed on one end face of the segment is a rectangle A or a rectangle C (FIG. 14), and a square formed on the other end face of the segment is a square B (FIG. 15). The unit 2A is configured by connecting the two segments so that the b-plane and d-plane and the a-plane and c-plane of the segments are adjacent to each other.
[0053]
As shown in FIG. 18, the surfaces of the segments are joined by fastening an ultra-high density glass wool plate with staples 5 and applying an aluminum foil tape 6 along the joining edge. Further, the glass wool as the sound absorbing material to be attached inside is adhered to the entire surface of the ultra-high density glass wool plate with an adhesive or the like, for example.
[0054]
Further, as shown in FIGS. 19 and 20, each segment or each block is bonded with, for example, a vinyl acetate adhesive so that there is no gap between ultra-high density glass wool plates, and an aluminum foil is formed along the bonding edge. The tape 6 is connected by sticking.
[0055]
Further, as shown in FIG. 21, the block and the flange are connected to each other through a connection duct 7 made of an ultra-high density glass wool plate. The connection duct 7 is configured by joining ultra-high density glass wool plates in the same manner as each surface in the segment, and the block and the connection duct are made of an adhesive and an aluminum foil in the same manner as the connection of each segment and each block. The connecting duct 7 and the flange 4 are connected by bolts and nuts.
[0056]
In the silencer in the present embodiment, the block 1 and the block 2 are connected so that the reference line B11 and the reference line B12 overlap when viewed from the direction of the arrow X in FIG. More specifically, the air passage formed by the unit 1A is divided into the air passage formed by the unit 2A and the air passage formed by the unit 2B, and the air passage formed by the unit 1B is also formed by the unit 2A. The air passage and the air passage formed by the unit 2B are connected so as to be divided. As a result, an air passage having a portion that can be seen through as shown by the hatched portion is formed for each unit, but the silencer in the present embodiment is as viewed from the direction of the arrow X, A ventilation path is formed between the units so that the squares B do not overlap each other.
[0057]
Since the silencer in the present embodiment has the above-described configuration, it can provide an excellent silencing effect and reduce pressure loss. First, the results of evaluating the pressure loss between the silencer in the present embodiment and a known silencer elbow are shown below.
[0058]
The silencer in the present embodiment has a glass density of 200 kg / m. ^Three And a glass density of 32 kg / m as the sound absorbing material. ^Three Glass wool was used. The sound absorbing material had a thickness of 25 mm and was attached to an ultrahigh density glass wool board. On the other hand, an outer-angle elbow having a duct diameter of 400 mm was used as a comparative silencing elbow. Note that the diameter of the silencer in the present embodiment was matched to the diameter of the silencer elbow.
[0059]
The pressure loss is obtained by connecting the silencer to a duct, changing the wind speed in the duct, and measuring the pressure difference before and after the silencer. The same applies to the silencer elbow. The results are shown in FIG. The pressure loss of the silencer in the present embodiment is equivalent to one silencer elbow.
[0060]
This is because the cross-sectional area of the air passage of the silencer in the present embodiment is constant, and the wall surface of the air passage is parallel to the direction of the arrow X in FIG. This is because the airflow direction of the airflow introduced into the air passage is not changed suddenly or more than right-angled, and the airflow is less susceptible to resistance in the airway.
[0061]
Moreover, the result of having evaluated the silencing effect of the silencer in this Embodiment and a well-known silencing elbow is shown below. In this evaluation, the silencer of the present embodiment, the silencer A, the silencer B, and the silencer elbow described above were used. The silencer A is configured in the same manner as the silencer of the present embodiment except that an iron plate is used instead of the ultra-high density glass wool plate. The silencer B is configured in the same manner as the silencer of the present embodiment except that the silencer B does not have a sound absorbing material, that is, is configured only by an ultra-high density glass wool plate. The silencer elbow was used as a known silencer elbow.
[0062]
The silencing effect is obtained by connecting the silencer or the like to be measured to a duct, measuring the sound volume for each predetermined frequency band on each of the upstream side and the downstream side of the silencer, and obtaining the difference between them. Evaluation was based on attenuation by a silencer or the like. The results are shown in FIG. The silencer in the present embodiment shows a silencing effect superior to one silencing elbow in all measured frequency bands.
[0063]
More specifically, the silencer in the present embodiment provides a silencing effect equivalent to that of two silencer elbows connected in series in a low-frequency region below 500 Hz. Moreover, in the sound range of 500 Hz or more and less than 2 kHz, the same silencing effect as that obtained by connecting two silencing elbows in series is achieved. Moreover, in a high sound range of 2 kHz or more, the same silencing effect as that in which four silencing elbows are connected in series is produced.
[0064]
Note that the silencer A and the silencer B also exhibit an excellent silencing effect corresponding to two to four silencing elbows depending on the frequency band, as compared to known silencing elbows.
[0065]
The reason why the silencer in the present embodiment exhibits the excellent silencing effect as described above is due to the shape of the air passage such as the constituent material of the air passage, the cross-sectional shape of the air passage and the arrangement of the cross-section. it is conceivable that.
[0066]
Examples of the silencing mechanism using the material constituting the air passage include the following mechanisms. That is, the sound that collides with the wall surface of the air passage is first absorbed by the sound absorbing material. Sound that is not absorbed by the sound-absorbing material is reflected in the air passage by the ultra-high density glass wool plate, and interferes with the sound that propagates through the air passage and cancels it out. Furthermore, the sound that is not reflected by the ultra-high density glass wool plate passes through the ultra-high density glass wool plate and attenuates during this time.
[0067]
In the silencer in the present embodiment, it is considered that noise is silenced by the above-described silencer mechanism, but the shape of the air passage is considered to synergistically enhance each of the silencer effects by the constituent materials. It is done. That is, in the silencer in the present embodiment, when viewed from the direction of the arrow X, since the air passages in which the squares B do not overlap each other are formed between the blocks, the sound propagating in the air passages is not ventilated. It is easy to collide with the road wall.
[0068]
In the silencer in the present embodiment, in the cross-sectional shape of the air passage, the center of the rectangle A and the center of the rectangle C are located away from the reference line passing through the center of the square B, and the axis of the air passage is used as a reference. When this is done, the wall surfaces of the air passages that face each other across this axis are in an asymmetric positional relationship. Since the sound propagating through the air flow path collides with the wall surface of the air flow path that forms a biased cross-sectional shape in this way, it is considered that the sound is reflected in various directions and the attenuation effect due to interference is further enhanced.
[0069]
Further, in the silencer in the present embodiment, the cross-sectional area does not change, but the cross-sectional shape changes slenderly along Bl1 or Bl2, and the sound propagating through the air passage tends to attenuate along the direction of changing slenderly. . And since there are two directions in which sound is easily attenuated, that is, the longitudinal direction of the rectangle A and the longitudinal direction of the rectangle C in one unit, the silencer in the present embodiment propagates through the air passage. It is thought that it is effective by the attenuation of the sound by doing.
[0070]
Further, in the silencer in the present embodiment, since one air passage is divided into two air passages and an air passage that joins one air passage is formed, two air passages are formed in one block. Is formed, and an air passage that branches and merges into two is formed, which is more effective by attenuation due to sound collision at the junction.
[0071]
Further, the silencer in the present embodiment has both end faces on the same axis and has a positional relationship where both end faces overlap when viewed from the direction of the arrow X, so that it can be installed instead of a straight body duct. . Moreover, the expansion width of the silencer along the arrow Y direction is about 1.4 times the width at the end, and the occupied space per obtained silencing effect is much smaller than that of a known silencing elbow.
[0072]
In addition, the silencer in the present embodiment has the same weight as one silencer elbow, and the weight per silencer effect obtained can be reduced compared to a silencer elbow with the same diameter, for example, on the ceiling of a music hall It can be applied to places where weight restrictions are imposed upon installation, such as when hanging.
[0073]
In addition, the silencer in the present embodiment has a constant cross-sectional area of the air passage and has a small pressure loss as described above, so there is no need to increase the blowing power in order to ensure the amount of blowing accompanying the installation of the silencer. In addition, it is possible to reduce the blower power of the blower serving as a noise generation source per installed number of silencers.
[0074]
In addition, the silencer in the present embodiment is formed with an air passage that is bent in a complicated manner by the wall surface of the air passage, so that a movable member such as a shielding plate is not required to obtain the above-described excellent noise reduction effect. It is maintenance-free and has an excellent noise reduction effect in the frequency band.
[0075]
In addition, although this embodiment demonstrated the example suitable for applying to a square air-conditioning duct as an example, the silencer of this invention is not limited to such embodiment, For example, as shown in FIG. Including one that forms an air passage that continuously changes in cross-sectional shape. This air passage is a semi-circular shape formed by dividing a circle vertically into two, and from a semi-circle A that is a first shape to a circle B that is a second shape, the circle is divided into two horizontally. The air passage is a semicircular formed and continuously changes to a semicircular C which is the third shape.
[0076]
In this ventilation path, the straight line that is the diameter in the semicircle A overlaps the reference line B11, the straight line that is the diameter in the semicircle C overlaps B12, and the circle B is in contact with the reference line B11 and in contact with the reference line B12. is there. The major axis C11 of the semicircular A is on the reference line B12, and the major axis C13 of the semicircular C is on the reference line B11. For example, by connecting units having such a cross-sectional shape in the same manner as in the present embodiment, a silencer that is suitably applied to a circular duct that is normally used in an exhaust pipe or the like is configured.
[0077]
Further, in the present embodiment, the first shape and the third shape in the present invention have been described as an example in which the cross-sectional shape of the duct to be connected to the silencer is divided into two. The silencer is not limited to such an embodiment, and includes, for example, one that forms an air passage that continuously changes in cross-sectional shape as shown in FIG. This ventilation path is a ventilation path that continuously changes from a vertically long ellipse A that is the first shape to a horizontally long ellipse C that is the third shape through a circle B that is the second shape. .
[0078]
In this air passage, the major axis of the ellipse A is parallel to the reference line B11 and the ellipse A is in contact with the reference line B11. The major axis of the ellipse C is parallel to the reference line B12 and the ellipse C is the reference line. The circle B is in contact with the reference line B12 and in contact with the reference line B12. The long axis center C11 of the ellipse A is on the reference line B12, and the long axis center C13 of the ellipse C is on the reference line B11. For example, when a unit having such a cross-sectional shape is formed by molding or the like at the time of pressure bonding of glass wool and applied to an air conditioning duct or the like, these shapes can be formed without gaps corresponding to the ellipse A or the ellipse C. By connecting these units using a connectable flange or connecting duct, it is possible to configure a silencer that is expected to have a more advanced sound reflection and attenuation effect due to interference.
[0079]
In the present embodiment, the first, second, and third shapes in the present invention have been described as an example having an air passage having a cross-sectional shape that partially overlaps, but the silencer of the present invention has such a silencer. It is not limited to embodiment, For example, what forms the ventilation path which changes continuously in cross-sectional shape as shown in FIG. 26 is included. This air passage is the book described above in that it changes continuously from the vertically long rectangle A which is the first shape to the horizontally long rectangle C which is the third shape through the square B which is the second shape. Although it is common with the ventilation path in the silencer of the embodiment, it differs from the above-described embodiment in that the first and third shapes are in a positional relationship that does not overlap each other.
[0080]
In such a ventilation path, since one unit includes a cross-sectional shape that is in a positional relationship that does not overlap with each other, it is effective in causing sound to collide with the wall surface of the ventilation path. Such a form is preferable when a high silencing effect is required with a small number of units, such as one unit or two units connected in series, and is effective when applied to a small machine, for example.
[0081]
【The invention's effect】
The silencer of the present invention includes a bent air passage and a sound absorbing material provided facing the air passage, and is a silencer for eliminating noise propagating through the air passage. A third portion which is a continuous portion with a constant area, and has a long and narrow shape through a second shape which is a point-symmetric or line-symmetric shape from a first shape whose cross-sectional shape is a slender shape. The major axis of the first shape and the major axis of the third shape are in a positional relationship intersecting each other, and the axis of the air passage passing through the center of symmetry in the second shape When a straight line extending in the direction is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are at least partially in the first shape and the third shape. From the low frequency band to the high frequency band because it is in a positional relationship that deviates from the reference axis in the range that overlaps the two shapes Wide can mute the sound of a frequency band, the pressure loss is small, it is possible to prevent the occurrence of self-noise.
[0082]
Further, in the present invention, when the first shape and the third shape are in a positional relationship that does not overlap with each other, it is more effective in silencing the sound in a wide frequency band from the low frequency band to the high frequency band. .
[0083]
Further, in the present invention, when the section in which the cross-sectional shape of the air passage changes continuously from the first shape to the third shape is one unit, the air passage has n units in series, When all cross-sectional shapes included in a single unit are targeted, if at least two cross-sectional shapes are in a positional relationship that does not overlap each other, the sound in a wide frequency band from the low frequency band to the high frequency band is muted. It is even more effective.
[0084]
In the present invention, a straight line including at least one point on the outer edge of the second shape is used as one reference line, and a straight line orthogonal to the one reference line and including at least one point on the outer edge of the second shape is used. When the other reference line is used, the first reference line overlaps with a straight line that extends along the longitudinal direction of the first shape and includes at least one point on the outer edge of the first shape, If the straight line including at least one point on the outer edge of the third shape and the other reference line overlap with each other along the longitudinal direction of the third shape, the pressure loss is small and self-noise is generated. It is possible to prevent this, and it is even more effective in silencing a wide frequency band.
[0085]
Further, in the present invention, the first shape is at a position where the center of the long axis of the first shape is on the other reference line, and the center of the long axis of the third shape is one reference Being at a position on the line is even more effective in reducing pressure loss.
[0086]
Moreover, in this invention, when the structure which has two ventilation paths and united so that 1st shape and 3rd elongate shape may be paralleled is made into 1 block, two blocks are connected. If configured, it is more effective in enhancing the silencing effect.
[0087]
In the present invention, the two blocks are mirror images of each other. If the long axes of the respective blocks are connected to each other at the connecting portion so as to be orthogonal to each other, it is possible to improve the silencing effect while reducing the pressure loss. More effective.
[0088]
In the present invention, if the first shape and the third shape are rectangles and the second shape is square, it is more effective to mute the sound in a wide frequency band.
[0089]
In the present invention, the air passage has at least two units in parallel, has a positional relationship in which the cross sections forming the first shape in each unit are adjacent to each other, and forms a third shape in each unit. If the cross-sections are adjacent to each other, two ventilation paths that are divided and merged with the same path length are formed, which is even more effective in silencing a wide frequency band.
[0090]
Also, in the present invention, when two units in parallel positional relationship are made into one block, if the two blocks are connected in series, a complicatedly bent air passage is formed, and a sound with a wide frequency band is formed. The two blocks are in a mirror image relationship with each other, and the second block is more effective in a positional relationship in which the second shapes do not overlap each other.
[0091]
In the present invention, the ventilation path is formed of an ultra-high density glass wool plate, and the sound absorbing material is glass wool supported on the ventilation side wall surface of the ventilation path, so that a wide frequency range from a low frequency band to a high frequency band can be obtained. The band noise can be silenced, the pressure loss is small, and the occurrence of self-noise can be prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a silencer according to an embodiment of the present invention.
2 is a view showing a state in which the block 1 of the silencer shown in FIG. 1 is viewed from the direction of arrow X in FIG.
3 is a view showing a state in which the block 1 of the silencer shown in FIG. 1 is viewed from the direction of arrow Y in FIG.
4 is a diagram showing a state in which the block 2 of the silencer shown in FIG. 1 is viewed from the direction of arrow X in FIG.
5 is a diagram showing a state in which the block 2 of the silencer shown in FIG. 1 is viewed from the direction of arrow Y in FIG.
6 is a diagram showing the positional relationship of the cross-sectional shape of the unit 1A shown in FIG. 1 when viewed from the direction of the arrow X in FIG.
7 is a diagram showing the unit 1A shown in FIG. 1 when viewed from the direction of arrow Y in FIG.
8 is a diagram showing the positional relationship of the cross-sectional shape of the unit 2A shown in FIG. 1 when viewed from the direction of the arrow X in FIG.
FIG. 9 is a diagram showing the unit 2A shown in FIG. 1 when viewed from the direction of arrow Y in FIG.
FIG. 10 is a front view of segments constituting the unit 1A shown in FIG.
FIG. 11 is a rear view of the segments constituting the unit 1A shown in FIG.
12 is a plan view of segments constituting the unit 1A shown in FIG. 1. FIG.
13 is a side view of segments constituting the unit 1A shown in FIG.
FIG. 14 is a front view of segments constituting the unit 2A shown in FIG.
15 is a rear view of a segment constituting the unit 2A shown in FIG.
FIG. 16 is a plan view of segments constituting the unit 2A shown in FIG.
FIG. 17 is a side view of segments constituting the unit 2A shown in FIG.
FIG. 18 is an enlarged cross-sectional view of a main part showing a joining portion of an ultra-high density glass wool plate in each segment.
FIG. 19 is an enlarged cross-sectional view of a main part showing a connection portion between segments and between blocks.
FIG. 20 is an enlarged cross-sectional view of a main part showing a connection portion between each segment and each block.
FIG. 21 is an enlarged cross-sectional view of a main part showing a connection portion between a block and a flange.
FIG. 22 is a graph showing the relationship between the wind speed in the duct and the pressure loss in the silencer in the present embodiment and a known silencing elbow.
FIG. 23 is a graph showing the relationship between the amount of attenuation with respect to the frequency band in the silencer according to the present embodiment and a known silencing elbow.
24 is a diagram showing a positional relationship of cross-sectional shapes when viewed from the direction of the arrow X in FIG. 1, of another example included in the present invention in the unit 1A shown in FIG.
25 is a diagram showing a positional relationship of cross-sectional shapes when viewed from the direction of the arrow X in FIG. 1 in another example included in the present invention in the unit 1A shown in FIG.
26 is a diagram showing the positional relationship of the cross-sectional shape when viewed from the direction of the arrow X in FIG. 1, of another example included in the present invention in the unit 1A shown in FIG.
[Explanation of symbols]
1, 2 blocks
1A, 1B, 2A, 2B unit
3, 4 Flange
5 Staples
6 Aluminum foil tape
7 Duct for connection
A First shape
B Second shape
C Third shape
Ba1, Ba2 Reference axis
B11, B12 reference line
C11 to C13, C21 to C23 Long axis center

Claims (10)

A silencer having a bent air passage and a sound absorbing material provided facing the air passage, and for eliminating noise propagating through the air passage,
The vent passage is a continuous portion with a constant cross-sectional area, and the cross-sectional shape is elongated from a first shape that is an elongated shape to a second shape that is a point-symmetrical or line-symmetrical shape. Including a portion that continuously changes to the third shape,
A longitudinal line passing through a central portion of the first shape and the third shape is a major axis, and an intermediate point of the major axis in the first shape and the third shape is a center of the major axis Because
The long axis of the first shape and the long axis of the third shape are in a positional relationship intersecting each other,
When the reference axis is a straight line that connects the symmetrical centers in the second shape and extends in a direction perpendicular to the plane including the second shape, the center of the long axis of the first shape and the first The center of the major axis of the three shapes is in a positional relationship deviating from the reference axis in a range where at least a part of each of the first shape and the third shape overlaps the second shape. Silencer.   The silencer according to claim 1, wherein the first shape and the third shape are in a positional relationship such that they do not overlap each other.   When the section where the cross-sectional shape of the air passage changes continuously from the first shape to the third shape is one unit, the air passage has n units in series, and n units The silencer according to claim 1, wherein at least two cross-sectional shapes are in a positional relationship so as not to overlap each other when all cross-sectional shapes included in the target are included. A silencer having a bent air passage and a sound absorbing material provided facing the air passage, and for eliminating noise propagating through the air passage,
The air passage is a continuous portion with a constant cross-sectional area, and the cross-sectional shape is elongated from a first shape that is an elongated shape to a second shape that is a point-symmetrical or line-symmetrical shape. Including a portion that continuously changes to the third shape,
The long axis of the first shape and the long axis of the third shape are in a positional relationship intersecting each other,
When a straight line extending in the axial direction of the air passage passing through the symmetrical center in the second shape is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are: In a positional relationship where at least a part of each of the first shape and the third shape overlaps the second shape, the position deviates from the reference axis.
When the section where the cross-sectional shape of the air passage changes continuously from the first shape to the third shape is one unit, the air passage has n units in series, and n units When all cross-sectional shapes included in the object are targeted, at least two cross-sectional shapes are in a positional relationship that does not overlap each other,
A straight line including at least one point on the outer edge of the second shape is set as one reference line, and a straight line orthogonal to the one reference line and including at least one point on the outer edge of the second shape is set as the other line. When used as a reference line,
A linear relationship that extends along the longitudinal direction of the first shape and includes at least one point on the outer edge of the first shape overlaps the one reference line,
It said third Mute device, characterized in that a straight line including at least one point on the outer edge and the other reference line is in a positional relationship to overlap shape with the third shape along the longitudinal direction of the extending.   The first shape is at a position where the center of the major axis of the first shape is on the other reference line, and the third shape is the center of the major axis of the third shape on the one reference line The muffler according to claim 4, wherein the silencer is located at a position. A silencer having a bent air passage and a sound absorbing material provided facing the air passage, and for eliminating noise propagating through the air passage,
The air passage is a continuous portion with a constant cross-sectional area, and the cross-sectional shape is elongated from a first shape that is an elongated shape to a second shape that is a point-symmetrical or line-symmetrical shape. Including a portion that continuously changes to the third shape,
The long axis of the first shape and the long axis of the third shape are in a positional relationship intersecting each other,
When a straight line extending in the axial direction of the air passage passing through the symmetrical center in the second shape is used as a reference axis, the center of the long axis of the first shape and the center of the long axis of the third shape are: In a positional relationship where at least a part of each of the first shape and the third shape overlaps the second shape, the position deviates from the reference axis.
The first shape and the third shape is a rectangle, silenced device, wherein the second shape is a square.   The air passage has at least two of the units in parallel, the cross-sections forming the first shape in each unit are adjacent to each other, and the cross-sections forming the third shape in each unit are adjacent to each other The silencer according to claim 5 or 6, wherein the silencer is in a positional relationship.   The silencer according to claim 7, wherein when the two units in the parallel positional relationship are made into one block, the two blocks are connected in series.   The silencer according to claim 8, wherein the two blocks are in a mirror image relationship with each other, and are in a positional relationship in which the second shapes do not overlap each other between the blocks.   The said ventilation path is formed with the ultra-high density glass wool board, and the said sound-absorbing material is the glass wool supported by the ventilation side wall surface of the said ventilation path, The any one of Claim 1 to 9 characterized by the above-mentioned. The silencer described in 1.

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