JP6516522B2 - Multi-blade fan - Google Patents

Description

  The present invention relates to an improvement of a multi-blade fan in which an impeller having a large number of blades arranged circumferentially in a spiral casing is accommodated, and a booster plate provided in a suction port of the casing and a silencer are integrated. The present invention relates to a multi-blade fan capable of being used as a blower of a combustion apparatus such as a boiler that requires pressure by increasing static pressure and simultaneously reducing noise of the blower leaking from the suction port to the outside. It is a thing.

  In general, a multi-blade fan is small and can obtain a large air volume, but has low blowing efficiency and low static pressure and relatively high noise. Further, a multi-blade fan is suitable for air conditioning, ventilation, etc. because of its small size, large air volume and low static pressure, and is not suitable for a fan for pushing into a combustion apparatus such as a boiler requiring pressure.

  However, small, lightweight, inexpensive multi-blade blowers may be used as blowers of combustion devices such as small boilers.

  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 multi-blade fan to adjust the air volume, part of the air A returns to the suction port 20a of the fan and from the suction port 20a There is a problem that the air pressure is blown off to the outside and the static pressure is lowered to deteriorate the blowing efficiency. In FIG. 12, reference numeral 22 denotes an impeller, and 23 denotes a damper shaft.

  Therefore, when using a multi-blade fan as a fan for pushing air into a combustion device such as a small boiler, a booster plate is attached to the multi-blade fan to increase the static pressure (the fan shown in FIG. 13). See the P-Q diagram representing the ability).

FIG. 14 shows an example of a conventional multi-blade fan attached with a booster plate 24. The multi-blade fan is rotatably accommodated in a spiral casing 20 having a suction port 20a and a discharge port 20b and the casing 20. The impeller 22, the damper 21 rotatably provided on the side of the discharge port 20b in the casing 20 via the damper shaft 23, and a motor (not shown) attached to the casing 20 for rotating the impeller 22. with which the mounting boosting plate 24 in meniscus shape to the suction port 20a of the casing 20, so that increase the static pressure in the suction port 20a so as not blown air.

15 to 17 show another example of a conventional multi-blade fan attached with a booster plate 24. The multi-blade fan has a spiral casing 20 having an inlet 20a and an outlet 20b, and a casing 20. The impeller 22 rotatably accommodated inside, the damper 21 rotatably provided via the damper shaft 23 on the side of the discharge port 20 b in the casing 20, and the motor flange 25 attached to the casing 20 and a motor 26 for rotating the impeller 22, so that the mounting of the booster plate 24 of L-shape suction port 20a of the casing 20, raising the static pressure in the suction port 20a so as not blown air .

  By the way, in the multi-blade fan in which the static pressure is increased by attaching the booster plate 24 in this way, as shown in FIGS. 18 (A) and (B), the suction of the casing 20 is taken for noise which is a drawback of the multi-blade fan. A silencer 27 is disposed on the side of the port 20a, and noise emitted from the suction port 20a is isolated by bending the suction passage of air, and noise is reduced by the sound absorbing material 28 lined on the inner wall surface of the silencer 27. I am trying to

  However, in the multi-blade fan in which the silencer 27 is disposed on the suction port 20a side of the casing 20, the air suction passage is bent for sound insulation, so that the air flow is reduced due to the resistance of the bent portion of the suction passage. There's a problem.

  Further, in order to obtain the muffling effect by 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 muffler 27 is enlarged. It is possible to reduce the volume by using a material having high sound absorption performance as the sound absorption material 28, but in this case, the sound absorption material 28 becomes expensive and the cost increases.

  On the other hand, multi-blade fans disclosed in Patent Document 1, Patent Document 2 and Patent Document 3 are known as a fan having a muffling function.

  That is, the fan disclosed in Patent Document 1 configures the nose portion of the casing in a Helmholtz resonance type muffling structure, and the multiblade blower disclosed in Patent Document 2 provides a resonator in the nose portion of the casing It is a thing.

  However, although the blowers disclosed in Patent Document 1 and Patent Document 2 are all effective for muffling noise generated at the nose of the casing, they are muffled for noise radiated from the suction port of the casing. And there is a problem that the muffling effect is small.

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

  However, since the fan disclosed in Patent Document 3 has a resonator disposed adjacent to the suction port, noise emitted from the suction port can be muffled, but resonance occurs downstream of the suction port. A space is required to arrange the vessel, and there is a problem that the apparatus becomes large.

Unexamined-Japanese-Patent No. 5-10293 Japanese Patent Application Laid-Open No. 7-332284 Unexamined-Japanese-Patent No. 2010-149741

  The present invention has been made in view of such problems, and an object thereof is to increase the static pressure and simultaneously reduce the noise of the fan leaking out from the suction port, and the pressure is required. An object of the present invention is to provide a multi-blade fan which can be used as a blower of 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 the suction port formed on one side wall of the casing by rotating an impeller provided in the casing, and the air is taken around the outer periphery of the casing. In a multi-blade fan discharged from a discharge port opened in a circumferential direction formed in a part of a wall, in a portion where the outer peripheral wall of the casing and the outer periphery of the impeller approach the suction port of the casing and the internal pressure in the casing becomes high. A linear suction formed by a booster plate which is disposed opposite to each other to suppress air being blown out from the suction port, and a suction guide wall integrally provided on the booster plate and in communication with the suction port of the casing and a muffler having a passage, the booster plate is integrally formed on the inner side plate of the muffler is attached to the side wall forming the suction port of the casing, part of the step-up plate cable There are particular features blocking the portion where the internal pressure in the casing is increased to and approaching the outer periphery of the outer peripheral wall and the impeller casing part of the suction port of the ring.

  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 be a resistance to suction of air, and the suction passage is formed in a straight line. It is characterized by

  According to a third aspect of the present invention, in the first aspect or the second aspect, the silencer may be a suction passage formed by a suction guide wall and two resonances disposed opposite to each other across the suction passage. It is characterized in that it is a Helmholtz resonance type silencer provided with a container, and one or more communication holes formed in the suction guide wall and respectively communicating the suction passage and the inside of the two resonance containers.

  According to a fourth aspect of the present invention, in the third aspect, the volumes of the two resonance containers are changed, and the communication hole communicating the one resonance container with the suction passage and the communication connecting the other resonance container with the suction passage. It is characterized in that the number and size of the holes are changed to correspond to two muffling frequencies.

  In a fifth aspect of the present invention according to the first aspect or the 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 present invention is characterized in that it is a Helmholtz resonance type silencer provided with one or more communication holes formed in the suction guide wall and communicating the suction passage with the inside of the resonance container.

Sixth aspect of the present invention, the first aspect of the present invention, the second invention, the third invention, the inner wall surface of the fourth invention or the in 5 any one of the suction guide wall forming the suction passage Is characterized in that a sound absorbing material is attached.

  According to a seventh invention of the present invention, in the first invention or the second invention, the silencer is formed of a plate-like sound absorbing material, and a suction passage communicating with the suction port of the casing and a suction passage interposed therebetween. It is characterized in that it is a silencer provided with two air space chambers arranged opposite to each other.

  In an eighth aspect of the present invention, in the first aspect or the second aspect, the silencer is a block-shaped sound absorbing material filled in the silencer and forming a suction passage communicating with the suction port of the casing. It is characterized in that it is a built-in silencer.

The ninth invention of the present invention is any one of the first invention, the second invention, the third invention, the fourth invention, the fifth invention, the sixth invention, the seventh invention or the eighth . in the inventions, the suction side of the air suction passage of the silencer, the cross-sectional shape formed by the sound absorbing material is arranged U-shaped muffler, the muffler and the U-shaped muffler with the suction passage It is characterized in that an air passage is provided between the

  In the multi-blade fan of the present invention, a booster plate is disposed at the suction port of the casing to suppress air being blown out from here, and a silencer having a suction passage communicating with the suction port is integrally provided on the booster plate. Since it is set as a structure, while raising static pressure, the noise of the fan leaked outside from a suction port can be reduced, and it can be used as a fan of combustion apparatuses, such as a boiler which requires a pressure.

  In the multi-blade fan of the present invention, the booster plate and the silencer are integrated and provided on the suction port side of the casing 1, so that the entire silencer can be made compact and can be manufactured inexpensively.

  In the multi-blade fan according to the present invention, since the silencer having the linear suction passage communicating with the suction port is disposed on the primary side of the booster plate, the silencer does not become a resistance to suction of air.

  In the multi-blade fan of the present invention, since the silencer is a Helmholtz resonance silencer, noise in a specific frequency band can be silenced. In particular, when the silencer includes two resonance vessels, the suction passage and the inside of each resonance vessel are respectively communicated by the communication holes, and the dimensions of the resonance vessels and the communication holes are changed, noises of different frequency bands are muffled. can do.

  In the multi-blade fan according to the present invention, since the suction guide wall forming the suction passage of the silencer communicating with the suction port also serves as a guide at the time of suction of air, turbulence of air generated near the suction port is rectified and suction noise Will be further reduced.

  In the multi-blade fan of the present invention, since the sound absorbing material is attached to the inner wall surface of the suction guide wall forming the suction passage, the noise can be further silenced.

It is a schematic front view of the multi-blade fan which concerns on one Embodiment of this invention. It is an II line fragmentary sectional view of FIG. It is a disassembled perspective view of the multi-blade fan shown in FIG. The silencer of a multi-blade 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 an explanatory view showing composition of a Helmholtz resonance type silencer typically. It is a graph which shows the comparison data of the fan noise of the conventional multi-blade fan and the multi-blade 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 one part of the multi-blade fan which concerns on other embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows one part of the multi-blade fan which concerns on other embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows one part of the multi-blade fan which concerns on other embodiment of this invention. It is a schematic plan view which fractures | ruptures and shows one part of the multi-blade fan which concerns on other embodiment of this invention. It is a schematic front view of the conventional multi-blade fan. It is a P-Q diagram showing capability of a multi-blade fan. It is a schematic front view of the same conventional multi-blade fan. It is a schematic front view of the same conventional multi-blade fan. FIG. 16 is a partial cross-sectional view taken along line II-II of FIG. It is a disassembled perspective view of the multi-blade fan shown in FIG.15 and FIG.16. (A) And (B) is a schematic cross-sectional view of the conventional multi-blade fan which arrange | positioned the silencer in the suction inlet side.

Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.
1 to 3 show a multi-blade fan according to an embodiment of the present invention, and the multi-blade fan is used as a fan for pushing air into a combustion apparatus such as a boiler requiring pressure.

  That is, the multi-blade fan rotates to the side of the discharge port 1 b in the casing 1, the spiral casing 1 having the suction port 1 a and the discharge port 1 b, the impeller 2 rotatably accommodated in the casing 1, A damper 3 freely provided, a motor 4 attached to the casing 1 for rotating the impeller 2, and a booster plate 5 disposed at the suction port 1 a of the casing 1 to suppress air being blown out from the suction port 1 a And a silencer 6 provided integrally with the booster plate 5 and having a linear suction passage 6a communicating with the suction port 1a of the casing 1, and the booster plate 5 and the silencer 6 are integrally formed. The booster plate 5 and the silencer 6 are attached to the side wall 1c of the casing 1 provided with the suction port 1a, 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 by a steel plate material, and a suction port 1a opened 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. In addition, in a part of the outer peripheral wall 1 e of the casing 1, a rectangular discharge port 1 b opening in the circumferential direction is formed. At the discharge port 1b of the casing 1, a damper 3 for adjusting the air volume is rotatably provided via a damper shaft 7.

  The said impeller 2 is arrange | positioned at equal intervals in the circumferential direction at the outer peripheral edge part of the disk-shaped end plate 2a formed with the steel plate material, and the disk-shaped end plate 2a, and an end part is the end plate 2a. A plurality of fixed blades 2b are provided, and are housed 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 the annular motor flange 8 ing. Each blade 2b of the impeller 2 is formed short in the radial direction of the impeller 2 and long in the axial direction.

  Further, in order to efficiently discharge the air sucked in from the suction port 1a of the casing 1, the impeller 2 brings the inner surface of the outer peripheral wall 1e of the casing 1 close to the impeller 2 near the discharge port 1b side. It is arrange | positioned 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, between the outer peripheral wall 1 e of the casing 1 and the outer periphery of the impeller 2 is formed an annular flow path through which the air taken in from the suction port 1 a flows, and the annular flow path is the upstream end The distance between the outer peripheral wall 1 e of the casing 1 and the outer periphery of the impeller 2 gradually increases from (the narrow portion) to the downstream end (the wide portion). In the narrow portion of the annular flow path, the outer peripheral wall 1 e of the casing 1 and the outer periphery of the impeller 2 come close to each other, and the internal pressure becomes high.

  The booster plate 5 is formed of a steel plate and has an L-shaped cross section, and a part thereof protrudes into the suction space of the impeller 2 and the other part is a part of the suction port 1a of the casing 1 Are attached to the side wall 1 c of the casing 1 in a state of closing the The booster plate 5 is integrally formed with the silencer 6 described later, and when the silencer 6 is attached to the side wall 1 c on the suction port 1 a side of the casing 1, the internal pressure in the casing 1 becomes high (casing It arrange | positions so that the outer peripheral wall 1e of 1 and the part to which the outer periphery of the impeller 2 is approaching may be.

  The silencer 6 is an inclined linear suction passage 6a formed by the suction guide wall 6b and communicating with the suction port 1a of the casing 1, and two resonance containers 6c disposed opposite to each other with the suction passage 6a interposed therebetween. And a silencer 6 of a Helmholtz resonance type including one or more communication holes 6d formed in the suction guide wall 6b and respectively communicating the suction passage 6a with the inside of the two resonance containers 6c, It is provided integrally with the booster plate 5 and disposed on the primary side (the side away from the suction port 1 a) of the booster plate 5 so as not to be a resistance to air suction.

  That is, as shown in FIGS. 1, 2 and 4, the silencer 6 includes an inner plate 6e, an outer wall 6f, a suction guide wall 6b, an outer plate 6g, two resonance containers 6c, and one or more communication holes 6d. The inner plate 6e, the outer wall 6f, the suction guide wall 6b, and the outer plate 6g, which constitute the silencer 6, are formed of steel plates.

Specifically, the inner side plate 6e is formed in a disk shape larger than the suction port 1a of the casing 1, and is formed in the same radius as the suction port 1a in agreement with a part of the suction port 1a of the casing 1 It has a semicircular opening. The plate-like semicircular portion of the inner side plate 6e forms a part of the booster plate 5, and the semicircular portion is integrally formed with a portion of the booster plate 5 that protrudes into the internal space of the impeller 2 There is.
Further, the inner side plate 6 e is attached to the side wall 1 c in which the suction port 1 a of the casing 1 is formed in a state where the semicircular opening coincides with a part of the suction port 1 a of the casing 1. At this time, the suction port 1a of the casing 1 is a plate-like semicircular portion of the inner plate 6e (a portion where pressure is increased at a portion where the outer pressure of the outer peripheral wall 1e of the casing 1 approaches the outer periphery of the impeller 2 and the internal pressure is high). (A part of the plate 5 is partially closed).

  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 in diameter 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 The linear suction passage 6a is formed.
Further, the shapes 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 side 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 multi-blade fan.
The suction guide wall 6b is accommodated in the outer wall 6f, and one end thereof is connected to the inner side plate 6e. At this time, the outlet side opening of the suction passage 6a of the suction guide wall 6b is in a state of being matched with the semicircular opening of the inner side plate 6e.

The outer side plate 6g is formed in a disk shape having the same size as the outer diameter of the outer wall 6f, and includes a semicircular opening that matches the inlet side opening of the suction passage 6a.
The outer side 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 disposed opposite to each other across the suction passage 6a, and one resonance container 6c has a part of the outer wall 6f, a part of the inner side plate 6e, and a pair of inclined guide plates 6b ₁ is formed in one guide plate 6b ₁ of the part of the outer plate 6 g, also the other resonance chamber 6c, a part of the portion of the outer wall 6f and 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 vessels 6c are formed in the same volume. The two resonance vessels 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. Note that one of the slanted guide plate 6b _1, to form one communicating hole 6d, on the other slanted guide plate 6b _1, and forms a plurality of communication holes 6d.

Then, the booster plate 5 is integrally provided on the secondary side (inner plate 6e side) of the silencer 6, and when the silencer 6 is attached to the side wall 1c on the suction port 1a side of the casing 1, the booster is boosted. The plate 5 is disposed at the suction port 1 a of the casing 1 and protrudes into the internal space of the impeller 2 and is in a state of closing a part of the suction port 1 a. 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, to provide the booster plate 5 integrally with the silencer 6 means that the booster plate 5 and the inner side plate 6 e (or the inclined guide plate 6 b ₁ ) are completely integrated, as a matter of course. In the case where the plate 5 and the inner plate 6e (or the inclined guide plate 6b ₁ ) are separately formed and the booster plate 5 and the inner plate 6e (or the inclined guide plate 6b ₁ ) are fixed later by welding or the like Shall also be included.

  As described above, since the silencer 6 includes the two resonance vessels 6c, and the suction passage 6a and the two resonance vessels 6c are communicated with each other through the communication holes 6d formed in the suction guide wall 6b, the Helmholtz resonance type The silencer 6 of the

FIG. 5 is an explanatory view schematically showing the structure of the Helmholtz resonance type silencer 6. The silencer 6 is a container 9 having a predetermined volume V, and one end is opened in the container 9 and the other end is Is constituted by a conduit 10 having a communication hole 10a opened to the flow path side.
Further, the muffling frequency of the Helmholtz resonance type silencer 6 is expressed by the following equation. Here, f is the muffling 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 muffling frequency is determined by the dimensions of the respective resonance containers 6c and the respective communication holes 6d, and two resonance containers 6c are provided. By changing the size of the hole 6d, noises of two different silencing frequencies can be silenced. The silencer 6 may be configured such that the resonance vessels 6c and the communication holes 6d all have the same size so as to silence noise of one silencing frequency.

  Thus, in the multi-blade fan described above, when the impeller 2 is rotated by the drive of the motor 4, external air is sucked into the suction passage 6a of the silencer 6, and the suction port 1a of the casing 1 It is taken into the inner space.

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

  In order to discharge the air sucked in from the suction port 1a efficiently, the multi-blade fan makes the outer peripheral wall 1e of the casing 1 and the impeller 2 approach each other in the vicinity of the discharge port 1b to narrow the gap. In the narrow portion, the outer peripheral wall 1 e of the casing 1 and the outer periphery of the impeller 2 come close to each other, and the internal pressure becomes high.

In such a multi-blade fan, when the air volume is reduced by rotationally controlling the damper 3 provided on the discharge port 1b side of the casing 1, the air sucked into the casing 1 has a high internal pressure in the casing 1 Since the air is blown back to the outside of the casing 1 from the portion of the suction port 1a close to the partial portion, the 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 is increased, the air blown back from the suction port 1a of the casing 1 is reduced. The pressure can be increased, the load on the multi-blade fan can be reduced, and the blowing efficiency can be improved, and the fan can be used as a fan of a combustion device such as a boiler requiring pressure.

Further, since the silencer 6 is disposed on the primary side of the booster plate 5, the noise of the blower leaking to the outside from the suction port 1a can be reduced.
In particular, since the silencer 6 is provided with two resonance vessels 6c, noise of two different muffling frequencies can be silenced if the dimensions of the resonance vessels 6c and the communication holes 6d are changed. In addition, when the respective resonance containers 6c and the respective communication holes 6d are all made the same size, noise of one muffling frequency can be muffled more reliably.

  FIG. 6 is a graph showing comparative data of fan noise of the conventional multi-blade fan and the multi-blade fan of the present invention, and the silencer 6 provided in the multi-blade fan of the present invention is designed to have a silencing frequency of 315 Hz. It is done. As apparent from the graph of FIG. 6, the noise of the multi-blade fan of the present invention is about 5 dB lower than that of the conventional multi-blade fan at a frequency of 315 Hz, and it can be seen that the noise reduction effect is obtained. However, the Main value is about 1 dB lower.

  As described above, since the multi-blade fan integrates the booster plate 5 and the silencer 6 and is provided on the suction port 1 a side of the casing 1, the static pressure is simultaneously increased and leaks from the suction port 1 a to the outside. The noise of the blower can be reduced, and it can be used as a blower of a combustion apparatus such as a boiler requiring pressure.

  Moreover, since the booster board 5 and the silencer 6 are integrated, the multi-blade fan can be made compact as well as the silencer 6 as a whole and can be manufactured inexpensively.

  Furthermore, since the multi-blade fan 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 acts as a resistance to suction of air. There is no

  Furthermore, since the multi-blade fan uses the silencer 6 as the Helmholtz resonance silencer 6, noise in a specific frequency band can be silenced. In particular, when the silencer 6 includes two resonance vessels 6c, the suction passage 6a and the inside of each resonance vessel 6c are communicated with each other by the communication holes 6d, and the dimensions of the resonance vessels 6c and the communication holes 6d are changed, Noise in different frequency bands can be silenced.

  Furthermore, in the multi-blade fan, since the suction guide wall 6b forming the suction passage 6a of the silencer 6 communicating with the suction port 1a also serves as a guide at the time of suction of air, air turbulence generated near the suction port 1a is rectified And the suction noise will be further reduced.

  FIG. 7 shows a multi-blade fan according to another embodiment of the present invention, in which the resonance vessel 6c of the silencer 6 is integrated into one.

  That is, the silencer 6 of the multi-blade fan includes a linear suction passage 6a formed by the suction guide wall 6b, a resonance container 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 more communication holes 6d which are formed and communicate the suction passage 6a with the inside of the resonance container 6c. The same reference numerals are attached to the same parts and members as those of the multi-blade fan shown in FIG.

In the silencer 6, since the resonance vessel 6c is one, the suction guide wall 6b forming the suction passage 6a is a part of the vertical guide plate 6b ₃ connected to the inner side plate 6e 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 function and effect as the multi-blade fan shown in FIGS. 1 to 3.

  FIG. 8 shows a multi-blade fan according to still another embodiment of the present invention, in which the sound absorbing material 6h is attached to the inner wall surface of the suction guide wall 6b forming the suction passage 6a of the silencer 6. It is a thing.

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, In the sound absorbing material 6h, through holes 6h ₁ respectively communicating with communication holes 6d formed in a pair of inclined guide plates 6b ₁ are formed, and the other configuration is the multi-blade fan shown in FIGS. 1 to 3 and It is configured the same.

  As the sound absorbing material 6h, for example, glass wool, rock wool, soft urethane foam, etc. are used. Further, the sound absorbing material 6h may be attached only to the inner wall surface of the suction guide wall 6b.

  The multi-blade fan shown in FIG. 8 described above can also exhibit the same function and effect as the multi-blade fan shown in FIGS. 1 to 3. In particular, since the sound absorbing material 6h is attached to the inner wall surface of the suction guide wall 6b forming the suction passage 6a, this multi-blade fan can further silence the noise.

  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 changed to the Helmholtz resonance type silencer 6 to use the silencer 6 of another structure. It is.

  That is, the silencer 6 of the multi-blade fan includes a linear suction passage 6a formed of a plate-like sound absorbing material 6h, and two air space chambers 6i disposed opposite to each other with the suction passage 6a interposed therebetween. The same parts and members as those of the multi-blade fan shown in FIG. 2 are denoted by the same reference numerals.

  The suction passage 6a is formed by arranging a pair of plate-like sound absorbing members 6h in a circular outer wall 6f in an opposed manner inclining with respect to the axis φ of the multi-blade fan, and the pair of plate-like A space surrounded by the sound absorbing material 6h and a part of the outer wall 6f is a suction passage 6a. The sound absorbing material 6 h may be attached to the inner wall surface of a part of the outer wall 6 f forming the suction passage 6 a.

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

  The multi-blade fan shown in FIG. 9 described above can also exhibit the same function and effect as the multi-blade fan shown in FIGS. 1 to 3.

  FIG. 10 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 the Helmholtz resonance type silencer 6 to use the silencer 6 of another structure. It is.

  That is, the silencer 6 of the multi-blade fan is linearly filled in the silencer 6 (in the space surrounded by the inner plate 6e, the outer wall 6f and the outer plate 6g) and communicating with the suction port 1a of the casing 1. The silencer is provided with a block-shaped sound absorbing material 6h forming the suction passage 6a, and the same parts and members as those of the multi-blade fan shown in FIG. The sound absorbing material 6 h may be filled only in the opposing 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 exhibit the same function and effect as the multi-blade fan shown in FIGS. 1 to 3.

  FIG. 11 shows a multi-blade fan according to still another embodiment of the present invention, wherein the multi-blade fan is further separated from the air intake port 1a side of the suction passage 6a of the silencer 6 integrated with the booster plate 5. The silencer 11 of a structure is arrange | positioned.

  That is, in the multi-blade fan, the silencer 11 having a U-shaped cross section formed of the sound absorbing material 6h is disposed on the suction side of the suction passage 6a of the silencer 6 integrated with the booster plate 5 Noise emitted from 1a is isolated by bending the air passage 12.

  The multi-blade fan shown in FIG. 11 described above can also exhibit the same function and effect as the multi-blade fan shown in FIGS. 1 to 3.

  In the above embodiment, although the external shape of the silencer 6 of the multi-blade fan is circular in consideration of manufacturability, the external shape of the silencer 6 is not limited to the circular one, and the casing Any shape may be used as long as the suction passage 6a communicating with the suction port 1a of 1 is provided and noise of the multi-blade fan can be silenced.

  Moreover, in said embodiment, although the resonance container 6c of the silencer 6 is made into one or two, in another embodiment, you may make the resonance container 6c of the silencer 6 three or more.

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 is a motor, 4a is a drive shaft of the motor, 5 is a booster plate, 6 is a silencer, 6a is a suction passage, 6b is a suction guide wall, 6b ₁ is an inclined guide plate, 6b ₂ is an arc-shaped 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 communicating hole, 11 is a silencer of another structure, 12 is an air passage, φ is an axis of the multi-blade fan, S is a conduit Area of the communication hole, L is the length of the conduit, V is the volume of the container.

Claims (9)

By rotating the impeller provided in the casing, air is sucked from the suction port formed on one side wall of the casing, and the air is discharged from the circumferentially opening discharge port formed on a part of the outer peripheral wall of the casing. In which the outer peripheral wall of the casing and the outer periphery of the impeller approach the suction port of the casing so as to face the portion where the internal pressure in the casing is high, and air is blown out from the suction port And a silencer having a linear suction passage formed by a suction guide wall integrally provided on the booster plate and communicating with the suction port of the casing, the booster plate being a suction member of the casing It is integrally formed on the inner side plate of the silencer attached to the side wall forming the mouth, and a part of the booster plate is a part of the suction port of the casing and the outer peripheral wall of the casing and the wing Multiblade blower, characterized in that closes a portion to be higher internal pressure in the casing car outer periphery close.   The multi-blade fan according to claim 1, wherein 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 in a straight line.   The silencer is formed in the suction passage formed by the suction guide wall, the two resonance containers disposed opposite to each other across the suction passage, the suction guide wall formed in the suction guide wall, and the suction passage and the two resonance containers respectively. It is a Helmholtz resonance type | mold silencer provided with the one or several communicating hole to make it communicate, The multi-blade fan of Claim 1 or 2 characterized by the above-mentioned.   While changing the volume of the two resonance vessels, changing the number and size of the communication holes that communicate one resonance vessel with the suction passage and the communication holes that communicate the other resonance vessel with the suction passage, it is possible to cope with two silencing frequencies. The multi-blade fan according to claim 3, characterized in that:   The silencer is one or a suction passage formed by the suction guide wall, one resonance container disposed adjacent to the suction passage, one formed in the suction guide wall to communicate the suction passage with the inside of the resonance container It is a Helmholtz resonance type silencer provided with a plurality of communicating holes, The multiblade fan according to claim 1 or 2 characterized by things. The multi-blade according to any one of claims 1, 2, 3, 4 and 5, wherein a sound absorbing material is attached to the inner wall surface of the suction guide wall forming the suction passage. Blower.   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 space chambers disposed opposite to each other across the suction passage. The multi-blade fan according to claim 1 or 2, characterized in that:   The silencer according to claim 1 or 2, wherein the silencer is a silencer provided with a block-shaped sound absorbing material that is filled in the silencer and forms a suction passage communicating with the suction port of the casing. Multi-blade blower. A silencer having a U-shaped cross section formed of a sound absorbing material is disposed on the air intake side of the suction passage of the silencer, and a muffler having a suction passage and the U-shaped silencer are disposed. The multi-blade fan according to any one of claims 1, 2, 3, 4, 5, 6, 7 or 8, wherein a passage is provided .

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