JP2007092672A - Blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively attenuate duct resonance noise according to installation conditions, in a blower used for ventilation blower equipment installed on a ceiling and wall surface. <P>SOLUTION: The blower and a muffler for the blower capable of effectively attenuating duct resonance noise entering an inside of a casing 5 from a duct 6 according to the installation conditions of the blower, and maintaining sound attenuation characteristics by providing a sound attenuation space 8 acoustically communicating to a casing 5 and including a sound attenuation function capable of changing sound attenuation characteristics on the main body of the blower. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a blower used for a ventilation blower mainly installed on a ceiling or a wall surface.

  Conventionally, this type of blower is known in which a Helmholtz resonator is provided in the nose portion in order to mute noise caused by interference between the impeller and the nose portion of the casing (see, for example, Patent Document 1).

  Hereinafter, the blower will be described with reference to FIG.

  As shown in the figure, a multi-blade fan 101 has a casing 103 that houses a rotatable impeller 102 having a large number of blades arranged at equal intervals in the circumferential direction. The casing 103 is formed with a nose portion 104 that protrudes into a flow path inside the casing. The casing 103 in the vicinity of the nose portion 104 has a resonator 105 for silencing a blade cutting sound generated by a predetermined rotation of the impeller 102. Is installed. The resonator 105 includes a Helmholtz resonator including a volume portion 106 having a predetermined volume, and a duct portion 108 having one end opened in the volume portion 106 and the other end opened as a resonator opening 107 on the flow path side. Has been.

  When the impeller 102 is rotated at a predetermined rotational speed, a blade cutting sound having a fundamental frequency as a product of the number of blades of the impeller 102 and the rotational speed per second is generated in the nose portion 104. The sound is muted by a resonator 105 provided near the nose portion 104.

  In addition, some of these types of blowers are silenced by providing a resonance chamber on the suction side of the casing (see, for example, Patent Document 2).

  Hereinafter, the blower will be described with reference to FIG.

As shown in the figure, the multiblade fan 109 includes a centrifugal multiblade fan 110, a case 111, and a suction box 112. An air intake chamber 113 and a resonance chamber 114 are formed in the suction box 112, and noise caused by the rotation of the centrifugal multiblade fan 110 is silenced by the resonance chamber 114.
Japanese Patent Laid-Open No. 7-332284 JP 7-228128 A

  In such a conventional blower, there is a problem that the noise reduction for the duct resonance noise that varies depending on the length of the duct connected to the blower is not taken into account, and there is a problem that the noise reduction level of the duct resonance noise is small. There is a demand for effective noise reduction.

  Further, there is a problem that the frequency band that can be silenced is narrow, and it is required to widen the frequency band that can be silenced.

  In addition, since the resonator and the casing communicate with each other through a hole, air enters and exits between the casing and the resonator, and there is a problem that the air blowing performance is deteriorated due to the disturbance of the flow. There is a problem that the desired silencing characteristics cannot be maintained due to moisture, oil, etc. entering the resonator or adhering to the communicating holes, and it is required to maintain the blowing performance and silencing characteristics. .

  In addition, since the frequency at which the resonator can mute cannot be easily changed, there is a problem that the muffled sound volume is reduced when the frequency band of the duct resonance noise, which varies depending on the duct length, does not match the preset muffler characteristics. It is required that the frequency band that can be easily silenced can be changed even after installation.

  In addition, when manufacturing a casing or a resonator by molding resin or the like, there is a problem that manufacturing of each wall surface and tube forming the resonator is complicated and costly, and it is required to suppress the manufacturing cost. Yes.

  The present invention solves such a conventional problem, can effectively mute duct resonance noise, has a wide frequency band to mute, can maintain the muffling characteristics, and can be installed even after the blower is installed. It is an object to provide a blower and a blower silencer that can change the frequency band that can be easily silenced and can reduce the cost.

  In order to achieve the above object, the blower of the present invention includes a main body having an opening, an impeller that is connected to the prime mover, a casing that communicates with the opening and surrounds the impeller, and an outdoor via a duct. The blower includes a duct connecting portion for communicating the inside of the casing, and the blower is configured to mute noise incident on the inside of the casing from the duct.

  By this means, a blower that can effectively mute noise incident from the duct into the casing is obtained.

  Another means is a blower provided with a silencing space having a silencing function, and having an acoustic communication portion that acoustically communicates the casing and the silencing space on the side facing the duct connection portion.

  By this means, it is possible to obtain a blower capable of improving the noise reduction performance by guiding the noise incident from the duct to the noise reduction space before being reflected by the inner wall of the casing.

  Another means is a blower including a plurality of silencing spaces having different silencing characteristics.

  By this means, a different frequency band can be silenced, and a blower that can widen the frequency band to be silenced is obtained.

  Another means is a blower using an acoustic transmission material having a high sound wave transmittance and a low air transmittance for the acoustic communication portion.

  By this means, an air blower that can suppress the entry and exit of air between the casing and the silencing space and can mute while suppressing the deterioration of the blowing performance is obtained.

  Another means is a blower in which an antibacterial substance is applied to a sound transmission material.

  By this means, it is possible to obtain a blower capable of suppressing the growth of bacteria, maintaining the sound transmission characteristics, and maintaining the sound deadening characteristics.

  Another means is a blower in which an antifungal substance is applied to a sound transmitting material.

  By this means, it is possible to obtain a blower capable of suppressing the growth of mold, maintaining the sound transmission characteristics and maintaining the sound deadening characteristics.

  Another means is a blower in which the acoustic communication part is removable.

  By this means, the acoustic communication part can be cleaned, regenerated or exchanged, and a blower capable of maintaining the sound transmission characteristics and maintaining the muffling characteristics can be obtained.

  Another means is a blower in which the silencing method of the silencing space is sound absorption by a sound absorbing material.

  By this means, a blower that can mute the intended frequency band and can effectively mute the noise that enters the casing from the duct is obtained.

  Another means is a blower in which the sound absorbing material is detachable.

  By this means, a sound absorbing material can be attached in accordance with the frequency of noise that changes depending on the state of attachment of the blower, and a blower capable of changing the frequency band that can be easily silenced even after the blower is installed is obtained.

  Another means is a blower in which the silencing method of the silencing space is a resonance silencer.

  By this means, a blower that can mute the intended frequency band and can effectively mute the noise that enters the casing from the duct is obtained.

  Another means is a blower in which the volume of the resonance silencer is variable.

  By this means, it is possible to change the silencing characteristics in accordance with the frequency of noise that varies depending on the mounting state of the blower, and to obtain a blower that can effectively silence the noise.

  Another means is a blower in which the volume of the resonance silencer can be changed by moving the movable surface up and down facing the opening of the main body.

  By this means, since the movable surface can be easily adjusted from the opening, a blower in which the silencing characteristics can be easily changed in accordance with the frequency of noise that varies depending on the mounting state of the blower even after the blower is installed.

  Another means is a blower that integrally manufactures the casing other than the movable surface of the resonance silencer and the casing.

  By this means, a blower capable of suppressing the manufacturing cost is obtained.

  Another means is a blower capable of changing the total area of the pipe portion of the resonance silencer.

  By this means, it is possible to change the silencing characteristics in accordance with the frequency of noise that changes depending on the mounting state of the blower, and to obtain a blower that can change the frequency band that can be easily silenced even after the blower is installed.

  Another means is a blower in which the silencing method of the silencing space is a combination of sound absorption by a sound absorbing material and noise reduction by a resonance silencer.

  By this means, it is possible to widen the frequency band that can be silenced, or to more effectively mute noise in the same frequency band, and to obtain a blower that can improve the silencing characteristics.

  Another means is a blower in which a hole is provided in the lower surface of the muffler space.

  By this means, a blower capable of draining the water accumulated in the silencing space and maintaining the silencing characteristics can be obtained.

  According to the present invention, the duct resonance noise can be effectively silenced, the frequency band to be silenced is wide, the silencing characteristics can be maintained, the frequency band to be easily silenced even after the blower is installed, and the cost can be reduced. A blower having an effect of being able to be suppressed can be provided.

  According to a first aspect of the present invention, there is provided a main body having an opening, an impeller connected to a prime mover and rotating, a casing that communicates with the opening and surrounds the impeller, an outdoor unit and the casing through a duct. A blower provided with a duct connecting part for communicating inside, wherein the noise entering the inside of the casing from the duct is silenced, and the noise entering the inside of the casing from the duct is effectively silenced It has the effect of being able to.

  In addition, the fan is provided with a silencing space having a silencing function, and is provided as a blower in which an acoustic communication portion for acoustically communicating the casing and the silencing space is provided on the side facing the duct connecting portion, and noise incident from the duct is casing. It has the effect | action that it can guide to a noise reduction space before reflecting on an inner wall, and can improve a noise reduction performance.

  Moreover, it is set as the air blower provided with the several silencing space which has a different silencing characteristic, and has the effect | action that a different frequency band can be silenced and the frequency band to silence can be widened.

  In addition, the acoustic communication part is a blower using a sound transmission material having a high sound wave transmittance and a low air transmittance, and can control the air in and out between the casing and the sound deadening space. It has the effect | action that it can suppress and silence and can mute.

  Moreover, it is a blower in which an antibacterial substance is applied to a sound transmission material, and has the effects of being able to suppress the growth of bacteria, maintaining the sound transmission characteristics, and maintaining the sound deadening characteristics.

  In addition, it is a blower in which an antifungal substance is applied to a sound transmitting material, which can suppress the growth of mold, maintain the sound transmitting characteristics, and maintain the sound deadening characteristics. .

  Also, the acoustic communication part is a removable blower, and the acoustic communication part can be cleaned, regenerated, or exchanged, and the sound transmission characteristics can be maintained and the sound deadening characteristics can be maintained. Have

  In addition, the sound deadening method of the sound deadening space is a blower that absorbs sound by a sound absorbing material, can mute the intended frequency band, and can effectively mute noise incident on the inside of the casing from the duct. Has an effect.

  In addition, the sound absorbing material is a blower that can be attached and detached, and the sound absorbing material can be attached according to the frequency of the noise that changes depending on the mounting state of the fan, and the frequency band that can be easily silenced even after the fan is installed is changed. It has the effect of being able to.

  In addition, the silencing method of the silencing space is a blower that is a resonance type silencer, can silence the intended frequency band, and can effectively silence the noise that enters the casing from the duct. Has an effect.

  In addition, the resonance type silencer has a variable volume blower, and the noise reduction characteristics can be changed in accordance with the frequency of noise that varies depending on the mounting state of the blower, and the noise can be effectively silenced. Have

  In addition, the volume of the resonance silencer is a blower that can be changed by moving the movable surface up and down facing the opening of the main body, and the movable surface can be easily adjusted from the opening. It has the effect that the silencing characteristic can be easily changed in accordance with the frequency of noise that changes depending on the state.

  Moreover, it is set as the air blower which manufactures except a movable surface of a resonance type silencer by integral molding with a casing, and has the effect | action that manufacturing cost can be suppressed.

  In addition, it is a blower that can change the total area of the pipe part of the resonance type silencer, the silencing characteristics can be changed according to the frequency of noise that changes depending on the mounting state of the blower, and it is easily silenced even after the blower is installed The frequency band can be changed.

  In addition, it is a blower that combines the sound absorption method of the sound deadening space with the sound absorption by the sound absorbing material and the sound absorption by the resonance type silencer, so that the frequency band that can be silenced is widened or noise in the same frequency band is more effectively The sound can be silenced, and the sound deadening characteristics can be improved.

  Moreover, it is set as the air blower which provided the hole in the lower surface of the noise reduction space, and has the effect | action which drains the water collected in the noise reduction space, maintains a noise reduction characteristic, and can maintain a noise reduction characteristic.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the main body 1 of the blower has an opening 2 on the side facing the room, an impeller 4 that is connected to the prime mover 3 and rotates, a casing 5 that communicates with the opening 2 and surrounds the impeller 4, A duct connecting portion 7 is provided for communicating between the outside and the inside of the casing 5 through the duct 6, and the room air flows into the casing 5 from the opening 2 by the rotation of the impeller 4, and passes through the impeller 4. The air is discharged from the duct connecting portion 7 to the outside through the duct 6. At this time, the sound of the prime mover 3 and the sound caused by the vibration thereof, the sound caused by the rotation of the impeller 4, the noise caused by the air flow itself and the collision of the air are generated and transmitted to the duct 6. However, when the resonance frequency determined by the volume of the duct 6 coincides with the frequency of the generated noise, the resonance noise having a relatively large sound pressure enters the casing 5 from the duct 6. Resonance noise attempts to enter the room through the opening 2 from the casing 5, but is incident on the casing 5 because the acoustic communication section 9 acoustically communicates with the casing 5 and has a silencing space 8 having a silencing function. The resonance noise generated can be silenced by the silencing space 8.

(Embodiment 2)
As shown in FIG. 2, the acoustic communication portion 9 of the casing 5 and the silencing space 8 is provided on the side facing the duct connection portion 7. Since the resonance noise incident from the duct 6 is directly incident on the sound deadening space 8 before being reflected by the inner wall of the casing 5, the sound deadening performance can be improved.

(Embodiment 3)
As shown in FIG. 3, two silencing spaces 8 are arranged, one of which is configured to silence noise in the low frequency range and the other in the high frequency range. With this configuration, different frequency bands can be silenced in each silencing space, and the frequency band to be silenced can be widened.

  In addition, it is good also as a structure which the frequency which mutes the several silencing space 8 is the same, and heightened the silencing effect of the specific frequency.

  In addition, it is good also as a structure which the some silencing space 8 each communicates with the casing 5 acoustically, and it is good also as a structure where the silencing spaces 8 mutually communicate acoustically.

(Embodiment 4)
As shown in FIG. 4, an acoustic transmission material 10 having a high sound wave transmittance and a low air transmittance is used for the acoustic communication portion 9. Examples of the sound transmission material include a material composed of a punching metal layer and a cloth layer, and a porous ceramic. By using the sound transmission material 10, it is possible to suppress the entry and exit of air between the casing 5 and the sound deadening space 8, and it is possible to mute while suppressing the deterioration of the blowing performance.

(Embodiment 5)
The antibacterial substance is applied to the sound transmission material 10 shown in FIG. 4, so that the growth of bacteria on the sound transmission material 10 can be suppressed, the sound transmission characteristics are maintained, and the sound deadening characteristics are maintained. Can do.

  Examples of the antibacterial substance include inorganic compounds that elute metal ions such as silver, copper, and zinc, and metal fine particles of silver, copper, and zinc.

(Embodiment 6)
4. An antifungal substance is applied to the sound transmission material 10 shown in FIG. 4, and the growth of mold on the sound transmission material 10 can be suppressed, and the sound transmission characteristics and the sound deadening characteristics can be maintained. Can do.

  Examples of the antifungal substance include organic nitrogen compounds, organic acid esters, organic iodine-based imidazole compounds, and benzazole compounds.

(Embodiment 7)
As shown in FIG. 5, the acoustic communication portion 9 is integrated with a part of the outer wall 11 constituting the casing 5, and can be inserted into and removed from a guide 12 provided on the outer wall 11. With this configuration, the acoustic communication unit 9 can be attached and detached, and cleaning, regeneration, or replacement can be performed when dust accumulates on the acoustic communication unit 9 due to long-term use. The sound transmission characteristics can be maintained, and the muffling characteristics can be maintained.

  In addition, it is more preferable that the acoustic communication portion 9 can be attached and detached directly from the opening 2.

(Embodiment 8)
As shown in FIG. 6, a sound absorbing material 13 having a specific sound absorbing characteristic is affixed inside the sound deadening space 8. Examples of the sound absorbing material include glass wool, rock wool, and flexible urethane foam. By affixing a sound absorbing material 13 having a characteristic of silencing a dominant frequency band in noise incident from the duct 6, the noise incident on the silencing space 8 from the acoustic communication portion 9 is effectively silenced. can do.

  The sound absorbing material 13 may be configured to be filled in the sound deadening space 8.

(Embodiment 9)
As shown in FIG. 7, a part of the surface 14 of the silencing space 8 can be opened and closed, and the sound absorbing material 13 installed in the silencing space 8 is detachable. Since the length and bending of the duct 6 change depending on the positional relationship between the room requiring exhaust and the outlet to the outside, the frequency of the resonance noise from the duct 6 changes depending on the mounting state of the blower. Since it is detachable, the sound absorbing material 13 can be easily changed in accordance with the frequency of noise after installation of the blower, and the sound can be effectively silenced.

  Note that the same effect can be obtained even when the sound absorbing material 13 itself is not detachable and the sound absorbing space 8 is detachable.

  It is more preferable that the sound absorbing material 13 or the sound deadening space 8 is configured to be directly removable from the opening 2.

(Embodiment 10)
As shown in FIG. 8, the silencing method of the silencing space 8 is constituted by a resonance silencer. The resonance silencer includes a tube portion 15 and a volume portion 16, and the sound deadening characteristics can be changed depending on the diameter and number of the tube portion 15 and the volume of the volume portion 16, and therefore, a dominant frequency band in noise incident from the duct. By setting the configuration of the tube portion 15 and the volume of the volume portion 16 so as to mute the noise, it is possible to effectively mute the noise that has entered the silence space 8 from the acoustic communication portion 9.

  In addition, the pipe part 15 is good also as a structure which served as the acoustic communication part 9. FIG.

(Embodiment 11)
As shown in FIG. 9, the volume part 16 of the noise reduction space 8 which uses the resonance type silencer as a noise reduction method is detachable. Since the length and bending of the duct 6 change depending on the positional relationship between the room requiring exhaust and the outlet to the outside, the frequency of the resonance noise from the duct 6 changes depending on the mounting state of the blower. Since it is detachable, it is possible to effectively mute by changing the sound deadening characteristic by exchanging the volume portion 16 according to the frequency of noise after installing the blower.

  It should be noted that the configuration may be such that the volume portion 16 is removable from the opening 2.

  It should be noted that the same effect can be obtained even in a configuration in which at least a part of the wall surface constituting the volume portion 16 is movable and the volume of the volume portion 16 is changed.

  The same effect can be obtained even if the volume is changed by filling a part of the volume 16 with a sealing material or the like.

(Embodiment 12)
As shown in FIG. 10, the volume of the volume portion 16 of the sound deadening space 8 using the resonance type silencer as a sound deadening method can be changed by the vertical movement of the movable surface 17 facing the opening 2. The length of the duct 6 and the degree of bending change depending on the positional relationship between the room requiring exhaust and the outlet to the outside. Therefore, the frequency of resonance noise from the duct 6 changes depending on the installation state of the blower. Since the movable surface 17 can be operated up and down from the opening 2, the volume of the volume portion 16 can be changed in accordance with the frequency of the noise to change the silencing characteristics, and the sound can be effectively silenced.

  The movable surface 17 may be provided with a threaded hole, connected to a threaded shaft, and the movable surface 17 may be moved by rotation of the shaft.

  Alternatively, a sealing material may be attached to the outer periphery of the movable surface 17 and moved by being press-fitted into the volume portion 16.

(Embodiment 13)
As shown in FIG. 11, the structure other than the movable surface 17 of the sound deadening space 8 using the resonance type silencer as a sound deadening method is manufactured integrally with the casing 5. Since the sound deadening space 8 and the casing 5 are integrally formed except for the movable surface 17, the number of parts and the number of assembling steps can be reduced while maintaining the function of changing the sound deadening characteristics, and the manufacturing cost can be suppressed.

(Embodiment 14)
As shown in FIG. 12, a part including the pipe part 15 of the noise reduction space 8 which uses the resonance type silencer as a noise reduction method is detachable. The length of the duct 6 and the degree of bending change depending on the positional relationship between the room requiring exhaust and the outlet to the outside. Therefore, the frequency of the resonance noise from the duct 6 changes depending on the mounting state of the blower. Since part including the pipe part 15 is detachable, the pipe part 15 is replaced after the installation of the blower, and the total area of the pipe part 15 is changed, so that the resonance type silencer of the resonance type silencer is adjusted to the noise frequency. The silencing characteristics can be changed to effectively silence the sound.

  It should be noted that it is more preferable that the tube portion 15 can be attached and detached directly from the opening 2.

  The method for changing the total area of the tube portion 15 may be a method of closing a portion of the tube portion 15 with aluminum tape or the like, or a method of opening a portion of the tube portion 15 that has been closed in advance.

(Embodiment 15)
As shown in FIG. 13A, the silencing method of the silencing space 8 is a combination of sound absorption by the sound absorbing material 13 and noise reduction by a resonance type silencer. For example, the sound absorbing material 13 is made of glass wool that is excellent in sound absorption in a frequency band of 1 kHz or higher, and the resonance silencer has a characteristic of muting noise of less than 1 kHz, so that the silencing characteristics of the respective methods are different. By setting, it is possible to widen the frequency band that can be silenced and to improve the silencing characteristics.

  In addition, as shown in FIG.13 (b), it is good also as a structure which affixes the sound absorption material 13 to the inner wall of the volume part 16 of a resonance type silencer.

  In addition, it is good also as a structure which muffles a specific frequency using the effect that the volume part as a resonator becomes pseudo-large by filling a sound-absorbing material into the sound-absorbing space.

  In addition, by making the frequency of sound absorption by the sound absorbing material 13 the same as the target frequency of noise reduction by the resonance type silencer, it is possible to mute the sound at a specific frequency in an enhanced manner.

(Embodiment 16)
As shown in FIG. 14, a drainage hole 19 is provided in the lower surface 18 of the sound deadening space 8. Since there is a drain hole 19 on the lower surface 18, water 20 accumulated due to condensation of moisture in the air that has flowed into the sound deadening space 8 due to the operation of the blower can be drained, so that the sound deadening characteristics of the sound deadening space are maintained. be able to.

  It should be noted that a configuration having a downward slope toward the drain hole 19 is preferable because a water flow toward the drain hole 19 is generated and drainage can be performed efficiently.

  The present invention can effectively mute duct resonance noise, and the frequency band to be muffled is wide, the muffling characteristic can be maintained, the frequency band that can be muffled easily even after the installation of the blower can be changed, and the cost can be reduced. It is possible to provide a blower and a blower silencer that can be easily attached to an existing blower.

Sectional side view which shows the air blower of Embodiment 1 of this invention. Front sectional drawing which shows the air blower of Embodiment 2 of this invention. Front sectional drawing which shows the air blower of Embodiment 3 of this invention. The perspective view which shows the casing and acoustic communication part of Embodiment 4 to 6 of this invention The perspective view which shows the casing and acoustic communication part of Embodiment 7 of this invention Sectional drawing which shows the air blower of Embodiment 8 of this invention. Sectional side view which shows the air blower of Embodiment 9 of this invention. Sectional drawing which shows the air blower of Embodiment 10 of this invention. Sectional side view which shows the air blower of Embodiment 11 of this invention. Sectional side view which shows the air blower of Embodiment 12 of this invention. A perspective view showing a casing and a silencing space according to a thirteenth embodiment of the present invention. Sectional side view which shows the air blower of Embodiment 14 of this invention. The figure which shows the structure of the air blower of Embodiment 15 of this invention ((a) Silencer block diagram by a sound-absorbing material and a resonance-type silencer, (b) Block diagram of a sound-absorbing material sticking) Sectional side view which shows the air blower of Embodiment 16 of this invention. Front sectional view showing a conventional blower Side sectional view showing a conventional blower

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Opening 3 Motor | power_engine 4 Impeller 5 Casing 6 Duct 7 Duct connection part 8 Silent space 9 Acoustic communication part 10 Sound transmission material 11 Outer wall 12 Guide 13 Sound absorbing material 14 Surface 15 Pipe part 16 Volume part 17 Movable surface 18 Lower surface 19 Drain hole 20 Water

Claims (16)

A main body having an opening; an impeller that is connected to and rotated by a prime mover; a casing that communicates with the opening and surrounds the impeller; and a duct connection portion that communicates the outside and the inside of the casing via a duct. A blower that silences noise incident on the inside of the casing from the duct. The blower according to claim 1, further comprising a silencing space having a silencing function, wherein an acoustic communication portion that acoustically communicates the casing and the silencing space is provided on a side facing the duct connection portion. The blower according to claim 1 or 2, further comprising a plurality of silencing spaces having different silencing characteristics. The blower according to any one of claims 1 to 3, wherein an acoustic transmission material having a high sound wave transmittance and a low air transmittance is used for the acoustic communication portion. The blower according to claim 4, wherein an antibacterial substance is applied to the sound transmission material. The blower according to claim 4 or 5, wherein an antifungal substance is applied to the sound transmission material. The blower according to any one of claims 1 to 6, wherein the acoustic communication part is removable. The air blower according to any one of claims 1 to 7, wherein the sound deadening method of the sound deadening space is a sound absorbing material. The blower according to claim 8, wherein the sound absorbing material is detachable. The blower according to any one of claims 1 to 7, wherein the silencing method of the silencing space is silenced by a resonance type silencer. The blower according to claim 10, wherein the volume of the resonance silencer is variable. The blower according to claim 11, wherein the volume of the resonance silencer can be changed by moving the movable surface up and down facing the opening of the main body. The blower according to claim 12, wherein the casing and the casing other than the movable surface of the resonance silencer are manufactured by integral molding. The blower according to any one of claims 10 to 13, wherein the total area of the pipe portion of the resonance silencer can be changed. The blower according to any one of claims 1 to 14, wherein the silencing method of the silencing space is a combination of sound absorption by a sound absorbing material and noise reduction by a resonance type silencer. The blower or the blower according to any one of claims 1 to 15, wherein a hole is provided on a lower surface of the sound deadening space.

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