JP2016176402A - Multiblade blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiblade blower which can reduce noise of a blower leaking to the outside from a suction port at the moment when a static pressure is increased, and which can be used as the blower of a combustion apparatus such as a boiler and the like which requires a pressure.SOLUTION: A multiblade blower which sucks air from a suction port 1a formed on one side wall 1c of a casing 1 by rotating an impeller 2 provided inside the casing 1 and discharges the air from a discharge port 1b opening in a circumferential direction formed at one part on an outer peripheral wall 1e of the casing 1 includes: a boost plate 5 arranged at the suction port 1a of the casing 1, and for suppressing the air being blown out from the suction port 1a; and a silencer 6 provided integrally at the boost plate 5 and having a suction passage 6a for communicating with the suction port 1a of the casing 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an improvement of a multiblade fan that accommodates an impeller formed by arranging a large number of blades in a spiral casing, and a booster plate and a muffler provided at a suction port of the casing are integrated. It is possible to reduce the noise of the blower that leaks outside from the suction port at the same time as increasing the static pressure, and it is related to a multiblade blower that can be used as a blower for a combustion device such as a boiler that requires pressure Is.

  In general, a multiblade fan is small and can take a large amount of air, but has low air blowing efficiency and low static pressure and relatively high noise. In addition, since the multiblade fan is small and has a large air volume and low static pressure, it is suitable for air conditioning, ventilation, and the like, and is not suitable for a blower for pushing into a combustion apparatus such as a boiler that requires pressure.

  However, a small, light, and inexpensive multi-blade blower may be used as a blower for a combustion device such as a small boiler.

  In this case, as shown in FIG. 12, when the damper 21 is provided on the discharge port 20b side of the casing 20 of the multiblade blower and the air volume is adjusted, a part of the air A returns to the suction port 20a of the blower, and the suction port 20a. There is a problem in that it is blown out and the static pressure is lowered, resulting in poor ventilation efficiency. In FIG. 12, 22 is an impeller and 23 is a damper shaft.

  Therefore, when the multiblade fan is used as a blower for pushing air into a combustion apparatus such as a small boiler, a booster plate is attached to the multiblade fan to increase the static pressure (the blower shown in FIG. 13). (See PQ diagram for capability).

  FIG. 14 shows an example of a conventional multi-blade fan to which a booster plate 24 is attached. The multi-blade fan is rotatably housed in a spiral casing 20 having a suction port 20a and a discharge port 20b. An impeller 22, a damper 21 rotatably provided on the discharge port 20 b side in the casing 20 via a damper shaft 23, and a motor (not shown) that is attached to the casing 20 and rotates the impeller 22. The booster plate 24 is attached in a meniscus shape to the discharge port 20b of the casing 20, and the static pressure is increased so that air does not blow out from the suction port 20a.

  15 to 17 show another example of a conventional multiblade fan to which a booster plate 24 is attached. The multiblade fan includes a spiral casing 20 having a suction port 20a and a discharge port 20b, and a casing 20. An impeller 22 rotatably accommodated therein, a damper 21 provided rotatably on a discharge port 20b side in the casing 20 via a damper shaft 23, and a motor flange 25 attached to the casing 20 And a motor 26 for rotating the impeller 22, and an L-shaped booster plate 24 is attached to the discharge port 20 b of the casing 20 to increase the static pressure so that air does not blow out from the suction port 20 a. .

  By the way, in the multiblade fan in which the booster plate 24 is attached and the static pressure is increased as described above, the noise that is a defect of the multiblade fan is sucked into the casing 20 as shown in FIGS. 18 (A) and (B). A silencer 27 is disposed on the side of the mouth 20a, and the noise emitted from the suction port 20a is insulated by bending the air suction passage, and the noise is reduced by the sound absorbing material 28 lined on the inner wall surface of the silencer 27. I am trying.

  However, in the multiblade fan in which the silencer 27 is disposed on the suction port 20a side of the casing 20, since the sound is insulated by bending the air suction passage, the amount of air flow is reduced due to the resistance of the bent portion of the suction passage. There's a problem.

  In addition, in order to obtain a silencing effect with the sound absorbing material 28, it is necessary to increase the volume of the sound absorbing material 28, and there is a problem that the silencer 27 is increased in size. If a material having high sound absorbing performance is used for the sound absorbing material 28, the volume can be reduced. However, in this case, the sound absorbing material 28 becomes expensive and the cost increases.

  On the other hand, multi-blade fans disclosed in Patent Literature 1, Patent Literature 2, and Patent Literature 3 are known as blowers having a silencing function.

  That is, the blower disclosed in Patent Document 1 is configured with a Helmholtz resonance type silencing structure in the nose portion of the casing, and the multiblade fan disclosed in Patent Document 2 is provided with a resonator in the nose portion of the casing. Is.

  However, each of the blowers disclosed in Patent Document 1 and Patent Document 2 is effective in silencing noise generated in the nose portion of the casing, but silences noise radiated from the suction port of the casing. There is a problem that the noise reduction effect is small.

  Furthermore, the blower disclosed in Patent Document 3 has a duct connected to the bell mouth portion of the blower, a suction port provided at the tip of the duct, and a resonator provided inside the duct.

  However, since the blower disclosed in Patent Document 3 has a resonator disposed adjacent to the suction port, noise radiated from the suction port can be silenced, but resonance is performed downstream of the suction port. There is a problem that a space for disposing the container is required and the apparatus is enlarged.

JP-A-5-10293 JP-A-7-332284 JP 2010-149741 A

  The present invention has been made in view of such problems, and its purpose is to increase the static pressure and simultaneously reduce the noise of the blower that leaks outside from the suction port, and requires pressure. An object of the present invention is to provide a multiblade fan that can be used as a blower for a combustion apparatus such as a boiler.

  In order to achieve the above object, according to a first aspect of the present invention, air is sucked from a suction port formed on one side wall of a casing by rotating an impeller provided in the casing, and the air is sucked into the outer periphery of the casing. In a multiblade fan that discharges from a discharge port that opens in a circumferential direction formed in a part of a wall, a booster plate that is arranged at the suction port of the casing and prevents air from being blown out from the suction port, and a booster plate A silencer having a suction passage that is integrally provided and communicates with a suction port of the casing is characterized.

  According to a second aspect of the present invention, in the first aspect, the silencer is disposed on the primary side of the booster plate so as not to resist air suction, and the suction passage is formed linearly. It is characterized by being.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the silencer includes a suction passage formed by a suction guide wall and two resonances arranged opposite to each other across the suction passage. A Helmholtz resonance type silencer is provided with a container and one or a plurality of communication holes formed in the suction guide wall to communicate the suction passage and the two resonance containers.

  According to a fourth aspect of the present invention, in the third aspect, the volume of the two resonance containers is changed, and the communication hole that communicates the one resonance container and the suction passage and the communication that communicates the other resonance container and the suction passage. It is characterized in that the number and size of the holes can be changed to support two silencing frequencies.

  According to a fifth aspect of the present invention, in the first or second aspect, the silencer includes a suction passage formed by a suction guide wall, and one resonance container disposed adjacent to the suction passage. The Helmholtz resonance type silencer is provided with one or a plurality of communication holes formed in the suction guide wall to communicate the suction passage and the inside of the resonance container.

  According to a sixth aspect of the present invention, in the first aspect, the second aspect, the third aspect, the fourth aspect, or the fifth aspect, the sound absorbing material is provided on the inner wall surface of the suction guide wall forming the suction passage. It is characterized by pasting.

  According to a seventh aspect of the present invention, in the first or second aspect, the silencer includes a suction passage formed of a plate-like sound absorbing material and communicating with the suction port of the casing, and the suction passage. It is characterized by a silencer having two air layer chambers arranged in opposition.

  According to an eighth aspect of the present invention, in the first or second aspect, the silencer includes a block-shaped sound absorbing material that fills the silencer and forms a suction passage that communicates with the suction port of the casing. It is characterized by the silencer provided.

  A ninth invention of the present invention is the first invention, the second invention, the third invention, the fourth invention, the fifth invention, the sixth invention, the seventh invention or the eighth invention. The silencer has a different structure on the air suction side of the suction passage of the silencer.

  In the multiblade fan of the present invention, a booster plate that suppresses air blowing from the suction port of the casing is disposed, and a silencer having a suction passage communicating with the suction port is integrally provided on the booster plate. Since it has composition, it can reduce the noise of the air blower which leaks outside from a suction port simultaneously with raising static pressure, and can be used as a blower of combustion devices, such as a boiler which requires pressure.

  In the multiblade fan of the present invention, since the booster plate and the silencer are integrated and provided on the suction port side of the casing 1, the entire silencer can be made compact and can be manufactured at low cost.

  In the multiblade fan of the present invention, the silencer having a linear suction passage communicating with the suction port is disposed on the primary side of the booster plate, so that the silencer does not become a resistance to air suction.

  Since the silencer is a Helmholtz resonance type silencer, the multiblade fan of the present invention can silence noise in a specific frequency band. In particular, when the silencer has two resonance vessels, the suction passage and each resonance vessel communicate with each other through communication holes, and the dimensions of each resonance vessel and communication hole are changed, the noise in different frequency bands is muted. can do.

  In the multiblade fan of the present invention, since the suction guide wall that forms the suction passage of the silencer that communicates with the suction port also serves as a guide when air is sucked in, the turbulence of the air generated near the suction port is rectified, and the suction sound Is further reduced.

  In the multiblade fan of the present invention, since the sound absorbing material is attached to the inner wall surface of the suction guide wall that forms the suction passage, noise can be further silenced.

It is a schematic front view of the multiblade fan which concerns on one Embodiment of this invention. It is the II sectional view taken on the line of FIG. It is a disassembled perspective view of the multiblade fan shown in FIG. The silencer of a multiblade fan is shown, (A) is a front side perspective view of a silencer, (B) is a back side perspective view of a silencer. It is explanatory drawing which shows typically the structure of a Helmholtz resonance type silencer. It is a graph which shows the comparison data of the fan sound of the conventional multiblade fan and the multiblade fan of this invention. It is a schematic plan view which fractures | ruptures and shows a part of multi-blade fan which concerns on other embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows a part of multi-blade fan which concerns on further another embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows a part of multi-blade fan which concerns on further another embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows a part of multi-blade fan which concerns on further another embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows a part of multi-blade fan which concerns on further another embodiment of this invention. It is a schematic front view of the conventional multiblade fan. It is a PQ diagram showing the capability of a multiblade fan. It is a schematic front view of the conventional multiblade fan similarly. It is a schematic front view of the conventional multiblade fan similarly. It is the II-II sectional view taken on the line of FIG. It is a disassembled perspective view of the multiblade fan shown in FIG.15 and FIG.16. (A) And (B) is a schematic cross-sectional view of the conventional multiblade fan which has arrange | positioned the silencer in the suction inlet side.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
1 to 3 show a multiblade blower according to an embodiment of the present invention, and the multiblade blower is used as a blower for pushing air into a combustion apparatus such as a boiler that requires pressure.

  That is, the multiblade blower rotates in a spiral casing 1 having a suction port 1a and a discharge port 1b, an impeller 2 rotatably accommodated in the casing 1, and a discharge port 1b side in the casing 1. A freely provided damper 3, a motor 4 that is attached to the casing 1 and rotates the impeller 2, and a booster plate 5 that is disposed in the suction port 1 a of the casing 1 and suppresses air blowing from the suction port 1 a. And a silencer 6 having a linear suction passage 6a provided integrally with the booster plate 5 and communicating with the suction port 1a of the casing 1, and the booster plate 5 and the silencer 6 are integrated. The booster plate 5 and the silencer 6 are attached to the side wall 1c of the casing 1 where the suction port 1a is provided, and the silencer 6 is disposed on the primary side of the booster plate 5 (the side away from the suction port 1a).

  The casing 1 is formed in a spiral shape from a steel plate material, and a suction port 1a that opens in the axial direction is formed on one side wall 1c of the casing 1 by attaching an annular bell mouth 1d to the side wall 1c. A rectangular discharge port 1b that opens in the circumferential direction is formed in a part of the outer peripheral wall 1e of the casing 1. A damper 3 that adjusts the air volume is rotatably provided at the discharge port 1 b of the casing 1 via a damper shaft 7.

  The impeller 2 is disposed at equal intervals in the circumferential direction on a disc-shaped end plate 2a formed of a steel plate material and an outer peripheral edge portion of the disc-shaped end plate 2a, and one end thereof is formed on the end plate 2a. A plurality of fixed blades 2b, accommodated in the casing 1, and attached to the drive shaft 4a of the motor 4 attached to the other side wall 1c of the casing 1 via an annular motor flange 8. ing. Each blade 2b of the impeller 2 is formed to be short in the radial direction of the impeller 2 and long in the axial direction.

  In addition, the impeller 2 causes the inner surface of the outer peripheral wall 1e of the casing 1 and the impeller 2 to approach each other in the vicinity of the discharge port 1b in order to efficiently discharge the air sucked from the suction port 1a of the casing 1. It arrange | positions in the casing 1 so that the clearance gap between the wall 1e and the outer periphery of the impeller 2 may become narrow. Therefore, an annular flow path through which air taken in from the suction port 1a flows is formed between the outer peripheral wall 1e of the casing 1 and the outer periphery of the impeller 2, and the annular flow path has an upstream end portion. The interval between the outer peripheral wall 1e of the casing 1 and the outer periphery of the impeller 2 is gradually increased from the (part having a narrow interval) to the downstream end portion (part having a wide interval). In the narrow portion of the annular flow path, the outer peripheral wall 1e of the casing 1 and the outer periphery of the impeller 2 approach each other, and the internal pressure is high.

  The step-up plate 5 is made of a steel plate and has an L-shaped cross-section. A part of the booster plate 5 projects into the internal space on the suction side of the impeller 2 and the other part is a part of the suction port 1 a of the casing 1. Is attached to the side wall 1c of the casing 1 in a closed state. The pressure plate 5 is formed integrally with a silencer 6 which will be described later. When the silencer 6 is attached to the side wall 1c of the casing 1 on the suction port 1a side, the internal pressure in the casing 1 is increased (casing). 1 and the outer peripheral wall 1e and the impeller 2 are disposed so as to face each other.

  The silencer 6 is formed of a suction guide wall 6b and is connected to the suction port 1a of the casing 1 and has an inclined linear suction passage 6a, and two resonance containers 6c arranged opposite to each other across the suction passage 6a. And a Helmholtz resonance type silencer 6 that is formed in the suction guide wall 6b and includes one or a plurality of communication holes 6d that respectively communicate the suction passage 6a and the two resonance containers 6c. It is provided integrally with the booster plate 5 and is arranged on the primary side of the booster plate 5 (side away from the suction port 1a) so as not to become resistance to air suction.

  That is, the silencer 6 includes an inner plate 6e, an outer wall 6f, a suction guide wall 6b, an outer plate 6g, two resonance vessels 6c, and one or a plurality of communication holes 6d, as shown in FIGS. The inner plate 6e, the outer wall 6f, the suction guide wall 6b, and the outer plate 6g constituting the silencer 6 are all formed of a steel plate material.

Specifically, the inner side plate 6e is formed in a disk shape larger than the suction port 1a of the casing 1, and matches a part of the suction port 1a of the casing 1 and has the same radius as the suction port 1a. It has a semicircular opening. The plate-like semicircular portion of the inner plate 6e forms a part of the booster plate 5, and the semicircular portion is formed integrally with the portion of the booster plate 5 protruding into the internal space of the impeller 2. Yes.
The inner plate 6e is attached to a side wall 1c that forms the suction port 1a of the casing 1 in a state where the semicircular opening matches a part of the suction port 1a of the casing 1. At this time, the suction port 1a of the casing 1 has a plate-like semicircular portion of the inner plate 6e where the outer peripheral wall 1e of the casing 1 and the outer periphery of the impeller 2 are close to each other and the internal pressure is high (this portion is increased in pressure). A part of the plate 5 is partially covered).

  The outer wall 6f is formed in a cylindrical shape having a diameter smaller than the outer diameter of the inner plate 6e and larger than the suction port 1a of the casing 1, and one end thereof is connected to the outer peripheral edge of the inner plate 6e.

Suction guide wall 6b includes a pair of inclined guide plates 6b ₁ arranged in opposite shape in a posture inclined with respect to the axis φ of the multi-blade fan, is connected to both side edges of the guide plates 6b ₁ facing shape communicating with the pair of arcuate guide plates 6b ₂ Metropolitan is composed of a pair of guide plates 6b ₁ and the pair of arc-shaped space surrounded by the guide plate 6b ₂ is of the casing 1 a suction port 1a arranged in It is formed in the straight suction passage 6a.
Further, the shape of the inlet side opening and the outlet side opening of the suction passage 6a are respectively formed in the same shape and the same size as the semicircular opening of the inner plate 6e, and the inlet side opening and the outlet side of the suction passage 6a. The opening is symmetrical about the axis φ of the multiblade fan.
And the suction guide wall 6b is accommodated in the outer wall 6f, and the one end part is connected to the inner side board 6e. At this time, the outlet side opening of the suction passage 6a of the suction guide wall 6b is in a state that matches the semicircular opening of the inner plate 6e.

The outer side plate 6g is formed in a disc shape having the same size as the outer diameter of the outer wall 6f, and has a semicircular opening that matches the inlet side opening of the suction passage 6a.
The outer plate 6g is connected to the other end of the outer wall 6f and the other end of the suction guide wall 6b, and closes the space between the outer wall 6f and the suction guide wall 6b.

The two resonance containers 6c are arranged opposite to each other with the suction passage 6a interposed therebetween, and one resonance container 6c includes a part of the outer wall 6f, a part of the inner plate 6e, and a pair of inclined guide plates 6b _1. One of the guide plates 6b ₁ and a part of the outer plate 6g, and the other resonance container 6c includes a part of the outer wall 6f, a part of the inner plate 6e, and a pair of inclined guide plates 6b _1. some of the other guide plate 6b ₁ and the outer plate 6g and is formed by. The two resonance containers 6c are formed in the same volume. The two resonance containers 6c may be formed in different volumes. Further, the inside of the two resonance chambers 6c, and has a communicating state by the space formed between a portion of the pair of arcuate guide plate 6b ₂ and outer wall 6f opposite thereto.

Hole 6d includes a pair of inclined guide plates 6b are formed respectively in _one communication hole 6d formed on one of the inclined guide plates 6b ₁ constituting the suction guide wall 6b includes a suction passage 6a and one resonance chambers 6c communicates, also communicating hole 6d formed on the other inclined guide plate 6b ₁ is communicated between suction passage 6a and the other resonance chambers 6c. One inclined guide plate 6b ₁ is formed with one communication hole 6d, and the other inclined guide plate 6b ₁ is formed with a plurality of communication holes 6d.

A booster plate 5 is integrally provided on the secondary side (inner side plate 6 e side) of the silencer 6, and the pressure is increased when the silencer 6 is attached to the side wall 1 c on the suction port 1 a side of the casing 1. The plate 5 is disposed in the suction port 1a of the casing 1 and protrudes into the internal space of the impeller 2 and closes a part of the suction port 1a. Incidentally, the step-up plate 5 is integrally provided on the inner plate 6e, it may be provided integrally with the end portion of one of the guide plates 6b ₁ of the booster plate 5 suction guide wall 6b. Here, providing the booster plate 5 integrally with the silencer 6 means that the booster plate 5 and the inner plate 6e (or the inclined guide plate 6b ₁ ) are completely integrated. When the plate 5 and the inner plate 6e (or the inclined guide plate 6b ₁ ) are formed separately, and the pressurizing plate 5 and the inner plate 6e (or the inclined guide plate 6b ₁ ) are later fixed by welding or the like. Shall also be included.

  As described above, the silencer 6 includes two resonance containers 6c, and the suction passage 6a and the two resonance containers 6c communicate with each other through the communication holes 6d formed in the suction guide wall 6b. Therefore, the Helmholtz resonance type It becomes the silencer 6 of.

FIG. 5 is an explanatory view schematically showing the configuration of a Helmholtz resonance type silencer 6. The silencer 6 includes a container 9 having a predetermined volume V, one end opened into the container 9, and the other end. Is composed of a pipe line 10 having a communication hole 10a that opens to the flow path side.
The silencing frequency of the Helmholtz resonance silencer 6 is expressed by the following equation. Here, f is the silencing frequency, C is the speed of sound, S is the area of the communication hole 10a of the conduit 10, L is the length of the conduit, and V is the volume of the container.

  Therefore, in the silencer 6 shown in FIG. 2, the silencing frequency is determined by the dimensions of each resonance container 6c and each communication hole 6d, and since the two resonance containers 6c are provided, each resonance container 6c and each communication container 6c are connected. By changing the size of the hole 6d, noise having two different silencing frequencies can be silenced. Note that the silencer 6 may be configured such that each resonance container 6c and each communication hole 6d have the same size and muffle noise of one silencing frequency.

  Thus, in the above-described multiblade fan, when the impeller 2 rotates by driving the motor 4, external air is sucked into the suction passage 6 a of the silencer 6, and the impeller 2 from the suction port 1 a of the casing 1. Captured in the internal space.

  The air taken into the internal space of the impeller 2 passes between the blades 2b of the impeller 2 and flows out into the annular flow path, flows in the annular flow path along the rotation direction of the impeller 2, It is discharged from the discharge port 1b of the casing 1 to the outside.

  In the multiblade blower, in order to efficiently discharge the air sucked from the suction port 1a, the outer peripheral wall 1e of the casing 1 and the impeller 2 are made closer to each other in the vicinity of the discharge port 1b to narrow the gap. In the narrow part, the outer peripheral wall 1e of the casing 1 and the outer periphery of the impeller 2 approach each other, and the internal pressure is high.

  In such a multiblade blower, when the damper 3 provided on the discharge port 1b side of the casing 1 is rotationally controlled to reduce the air volume, the air sucked into the casing 1 has a high internal pressure in the casing 1. Since the air is blown back out of the casing 1 from the portion of the suction port 1a closer to the part, the air blowing efficiency is deteriorated.

  However, since the multi-blade fan includes the booster plate 5 disposed so as to face the portion where the internal pressure in the casing 1 increases, the air blown back from the suction port 1a of the casing 1 is reduced, and the While being able to raise a pressure, the load of a multiblade fan will reduce and ventilation efficiency will improve and it can be used as a blower of combustion apparatuses, such as a boiler which requires a pressure.

Moreover, since the said multiblade fan has arrange | positioned the silencer 6 at the primary side of the pressure | voltage rise board 5, it can reduce the noise of the air blower leaking outside from the suction inlet 1a.
In particular, since the silencer 6 includes two resonance containers 6c, when the dimensions of each resonance container 6c and each communication hole 6d are changed, noise having two different silence frequencies can be silenced. Further, when all the resonance containers 6c and the respective communication holes 6d have the same size, it is possible to more reliably mute the noise of one muffling frequency.

  FIG. 6 is a graph showing comparison data of the fan sound of the conventional multiblade fan and the multiblade fan of the present invention. The silencer 6 provided in the multiblade fan of the present invention is designed so that the muffler frequency is 315 Hz. It has been done. As is apparent from the graph of FIG. 6, at the frequency of 315 Hz, the multiblade fan of the present invention has a noise reduction of about 5 dB compared to the conventional multiblade fan, and it can be seen that there is a silencing effect. However, the Main value is reduced by about 1 dB.

  In this way, the multiblade fan integrates the booster plate 5 and the silencer 6 and is provided on the suction port 1a side of the casing 1, so that the static pressure is increased and at the same time leaks out from the suction port 1a. The noise of the blower can be reduced, and the blower can be used as a blower of a combustion apparatus such as a boiler that requires pressure.

  In addition, since the multi-blade fan integrates the booster plate 5 and the silencer 6, the entire silencer 6 can be made compact and can be manufactured at low cost.

  Furthermore, since the multiblade blower has the silencer 6 having the linear suction passage 6a communicating with the suction port 1a on the primary side of the booster plate 5, the silencer 6 becomes resistance to air suction. There is no.

  Further, since the silencer 6 is a Helmholtz resonance type silencer 6 in the multiblade blower, noise in a specific frequency band can be silenced. In particular, when the silencer 6 includes two resonance containers 6c, the suction passages 6a and the resonance containers 6c communicate with each other through the communication holes 6d, and the dimensions of the resonance containers 6c and the communication holes 6d are changed. Noise in different frequency bands can be silenced.

  Furthermore, in the multiblade blower, since the suction guide wall 6b that forms the suction passage 6a of the silencer 6 that communicates with the suction port 1a also serves as a guide when air is sucked in, the turbulence of air that has occurred near the suction port 1a is rectified. As a result, the suction sound is further reduced.

  FIG. 7 shows a multiblade blower according to another embodiment of the present invention, and the multiblade blower has a single resonance container 6 c of the silencer 6.

  That is, the silencer 6 of the multiblade blower includes a linear suction passage 6a formed by the suction guide wall 6b, a single resonance vessel 6c disposed adjacent to the suction passage 6a, and a suction guide wall 6b. The Helmholtz resonance type silencer 6 is provided with one or a plurality of communication holes 6d that are formed and communicate with the suction passage 6a and the inside of the resonance vessel 6c. In addition, the same reference number is attached | subjected to the site | part and member same as the multiblade fan shown in FIG.

Wherein the muffler 6, since the one resonance container 6c, suction guide wall 6b which forms the suction passage 6a includes a portion of which is connected to the inner plate 6e vertical shaped guide plate 6b ₃ and the outer wall 6f It is composed of a part with a space surrounded by the vertical-shaped guide plate 6b ₃ and the outer wall 6f is formed on the suction passage 6a communicating with the inlet 1a of the casing 1. The suction passage 6a is formed in a semicircular shape.

  The multi-blade fan shown in FIG. 7 described above can also exhibit the same effects as the multi-blade fan shown in FIGS.

  FIG. 8 shows a multiblade fan according to still another embodiment of the present invention, and the multiblade fan has a sound absorbing material 6h attached to the inner wall surface of the suction guide wall 6b forming the suction passage 6a of the silencer 6. Is.

That is, the multiblade blower, the suction guide pair that forms a wall 6b inclined guide plates 6b ₁ and the pair of arc-shaped on the inner wall surface of the guide plate 6b ₂ a plate-shaped noise absorbing member 6h with paste respectively, is obtained by forming the through-holes 6h ₁ to respectively communicating with the communication hole 6d formed in the pair of inclined guide plates 6b ₁ to the sound-absorbing material 6h, other configurations are the multiblade blower shown in FIGS. 1 to 3 It is structured the same.

  For example, glass wool, rock wool, soft urethane foam, or the like is used as the sound absorbing material 6h. The sound absorbing material 6h may be attached only to the inner wall surface of the suction guide wall 6b.

  The multiblade fan shown in FIG. 8 described above can also achieve the same operational effects as the multiblade fan shown in FIGS. In particular, since this multiblade fan has the sound absorbing material 6h attached to the inner wall surface of the suction guide wall 6b forming the suction passage 6a, the noise can be further silenced.

  FIG. 9 shows a multi-blade fan according to still another embodiment of the present invention, in which the structure of the silencer 6 is replaced with a Helmholtz resonance silencer 6 to form a silencer 6 having a different structure. It is.

  That is, the silencer 6 of the multi-blade blower includes a linear suction passage 6a formed by a plate-like sound absorbing material 6h and two air layer chambers 6i arranged opposite to each other across the suction passage 6a. The silencer 6 is provided, and the same parts and members as those of the multiblade fan shown in FIG.

  The suction passage 6a is formed by arranging a pair of plate-like sound absorbing materials 6h in a circular outer wall 6f so as to face each other in a posture inclined with respect to the axis φ of the multiblade fan. A space surrounded by the sound absorbing material 6h and a part of the outer wall 6f is a suction passage 6a. In addition, you may make it affix the sound absorption material 6h also to the partial inner wall surface of the outer wall 6f which forms the suction path 6a.

  Of the two air layer chambers 6i, one air layer chamber 6i includes a part of the outer wall 6f, a part of the inner plate 6e, a sound absorbing material 6h of the pair of sound absorbing materials 6h, and a part of the outer plate 6g. The other air layer chamber 6i is formed by a part of the outer wall 6f, a part of the inner plate 6e, the other sound absorbing material 6h of the pair of sound absorbing materials 6h, and a part of the outer plate 6g. ing. The two air layer chambers 6i are formed in the same volume. The two air layer chambers 6i may be formed in different volumes.

  The multiblade fan shown in FIG. 9 described above can also exhibit the same operational effects as the multiblade fan shown in FIGS.

  FIG. 10 shows a multi-blade fan according to still another embodiment of the present invention. The multi-blade fan has a silencer 6 with a different structure by replacing the silencer 6 with a Helmholtz resonance silencer 6. It is.

  That is, the silencer 6 of the multiblade blower is filled in the silencer 6 (in the space surrounded by the inner plate 6e, the outer wall 6f, and the outer plate 6g) and communicates with the suction port 1a of the casing 1. The silencer includes a block-shaped sound absorbing material 6h that forms the suction passage 6a, and the same reference numerals are assigned to the same parts and members as those of the multiblade fan shown in FIG. Note that the sound absorbing material 6 h may be filled only in the facing portion on the inner peripheral surface side of the silencer 6, or may be filled in the entire inner peripheral surface side of the silencer 6.

  The multi-blade fan shown in FIG. 10 described above can also achieve the same effects as the multi-blade fan shown in FIGS.

  FIG. 11 shows a multi-blade fan according to still another embodiment of the present invention, and the multi-blade fan is further separated from the air suction port 1 a side of the suction passage 6 a of the silencer 6 integrated with the booster plate 5. A silencer 11 having a structure is arranged.

  That is, the multiblade blower is provided with a silencer 11 having a U-shaped cross section formed by a sound absorbing material 6h on the suction side of the suction passage 6a of the silencer 6 integrated with the booster plate 5, and a suction port. The noise radiated from 1a is sound-insulated by bending the air passage 12.

  The multiblade fan shown in FIG. 11 described above can also achieve the same operational effects as the multiblade fan shown in FIGS.

  In the above embodiment, the external shape of the silencer 6 of the multiblade fan is circular in consideration of manufacturability, but the external shape of the silencer 6 is not limited to a circular shape, and the casing Any shape may be employed as long as it has a suction passage 6a communicating with one suction port 1a and can mute the noise of the multiblade fan.

  In the above embodiment, one or two resonance containers 6c of the silencer 6 are used. However, in other embodiments, three or more resonance containers 6c of the silencer 6 may be used.

1 is a casing, 1a is a suction port, 1b is a discharge port, 1c is a side wall, 1d is a bell mouth, 1e is an outer peripheral wall, 2 is an impeller, 2a is a disk-shaped end plate, 2b is a blade, 3 is a damper, 4 motor, 4a drive shaft of the motor, 5 is boosted plate, 6 muffler, 6a is suction passage, 6b is suction guide wall, 6b ₁ is inclined guide plates, 6b ₂ is arcuate guide plate, 6b ₃ is a vertical-shaped guide plate, 6c are resonance chambers, 6d are communicating hole, 6e inner plate, 6f outer wall, 6 g the outer plate, 6h sound absorbing material, 6h ₁ through hole, 6i air layer chamber, 7 is a damper shaft, 8 is a motor flange, 9 is a container, 10 is a conduit, 10a is a communication hole, 11 is a silencer of another structure, 12 is an air passage, φ is the axis of a multiblade fan, and S is a conduit , L is the length of the conduit, and V is the volume of the container.

Claims (9)

  By rotating an impeller provided in the casing, air is sucked from a suction port formed on one side wall of the casing, and the air is discharged from a discharge port opened in a circumferential direction formed in a part of the outer peripheral wall of the casing. In the multiblade blower, the booster plate is arranged at the suction port of the casing and prevents air from being blown out from the suction port, and the suction passage is provided integrally with the booster plate and communicates with the suction port of the casing. A multi-blade blower comprising a silencer.   2. The multiblade fan according to claim 1, wherein the silencer is disposed on the primary side of the booster plate so as not to become resistance to air suction, and the suction passage is formed in a straight line.   The silencer is composed of a suction passage formed by a suction guide wall, two resonance containers arranged opposite to each other with the suction passage interposed therebetween, and a suction passage and two resonance containers formed in the suction guide wall. The multiblade blower according to claim 1 or 2, wherein the multiblade blower is a Helmholtz resonance type silencer including one or a plurality of communication holes that communicate with each other.   The volume of the two resonance vessels can be changed, and the number and size of the communication hole that communicates one resonance vessel and the suction passage and the communication hole that communicates the other resonance vessel and the suction passage can be changed to support two silencing frequencies. The multiblade fan according to claim 3, wherein the multiblade fan is provided.   The silencer includes a suction passage formed by the suction guide wall, one resonance container disposed adjacent to the suction passage, and one or more formed in the suction guide wall to communicate the suction passage and the inside of the resonance container. The multiblade blower according to claim 1 or 2, wherein the multiblade blower is a Helmholtz resonance type silencer including a plurality of communication holes.   The multiblade blower according to claim 1, 2, 3, 4, or 5, wherein a sound absorbing material is attached to an inner wall surface of a suction guide wall forming a suction passage.   The silencer is a silencer comprising a suction passage formed of a plate-like sound absorbing material and communicating with the suction port of the casing, and two air layer chambers arranged opposite to each other across the suction passage. The multiblade fan according to claim 1 or 2, wherein the multiblade fan is characterized.   3. The silencer according to claim 1, wherein the silencer is a silencer provided with a block-shaped sound absorbing material that fills the silencer and forms a suction passage that communicates with a suction port of the casing. Multi-blade blower.   The silencer having a different structure is disposed on the air suction side of the suction passage of the silencer. The claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, characterized in that The multiblade fan according to claim 7 or claim 8.

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