JP2009127436A - Low noise equipment for blowers - Google Patents

Abstract

An object of the present invention is to provide a low-noise device for a blower that improves the sound absorption effect of each sound range with respect to the noise of the blower and realizes the noise reduction of the surroundings.
In a low noise device for a blower in which a suction port 4 and a blower outlet 5 are opened in a casing 2 in which a blower 1 is installed, and at least a suction cover 6 having a sound absorbing function is attached to the suction port 4. The cover 6 is attached to the suction port 4 of the housing 2 to form a non-linear air passage that communicates outside air with the suction port 4 of the housing 2, and the inner surface that faces the suction port 4 of the housing 2. In addition, a sound absorbing layer 9 in which a plurality of sound absorbing structures having different sound absorbing characteristics are laminated is formed.
[Selection] Figure 2

Description

  The present invention relates to an apparatus for reducing noise generated in a blower.

  Noise generated from the blower has an adverse effect on the surrounding environment. For example, in a blower mounted on a car wash machine, serious noise damage is caused to the living environment of local residents, and cases that cause troubles are increasing. Therefore, in recent years, in order to prevent the drive sound of the blower from leaking to the outside as much as possible, a fan that surrounds the blower with a sound absorbing wall has been proposed (Patent Document 1).

  By the way, in such a sound absorbing structure, the sound absorbing ability itself depends on the sound absorbing performance of the sound absorbing wall surrounding the blower. Glass wool, which is generally widely used as a sound absorbing material, has a characteristic that it has a high sound absorption rate from the high sound range to the mid sound range and a low sound absorption rate in the low sound range. Therefore, as a sound absorption material for the noise range (300 to 1000 Hz) of the blower. Slightly lack of ability. Therefore, an air layer has been provided on the back surface of the sound absorbing material to improve the sound absorption coefficient in the low frequency range. According to such a sound absorbing structure using glass wool and a back air layer, an average sound absorbing effect can be exhibited in the noise range of the blower.

However, when viewed at the sound pressure level, the noise range of the blower shows a high sound pressure in the middle sound range, and thus a transmitted sound that is relatively centered on the middle sound range is generated. Therefore, the present situation is that further improvement of the sound absorption effect is required for this mid-range.
JP 2005-315218 A

  The problem to be solved by the present invention is to provide a low-noise device for a blower that improves the sound absorption effect of each sound range with respect to the noise of the blower and realizes the noise reduction of the surroundings.

  In order to solve such a problem, the present invention provides a low noise for a blower in which a suction port and a blower outlet are opened in a casing in which the blower is installed, and at least a suction cover having a sound absorbing function is attached to the suction port. In the apparatus, the intake cover is attached to the suction port of the housing, forms a non-linear air passage that communicates the suction port of the housing with the outside air, and on the inner surface facing the suction port of the housing, A sound absorbing layer is formed by laminating a plurality of sound absorbing structures having different sound absorbing characteristics. The sound absorbing layer is formed in the order of aluminum sintered material, glass wool, and air layer from the noise source to the inner surface of the intake cover.

  ADVANTAGE OF THE INVENTION According to this invention, the sound absorption effect with respect to each sound range of an air blower increases, and the noise which leaks around can be reduced. In particular, the sound absorption layer in which the aluminum sintered material, glass wool, and air layer are arranged in order from the noise source to the inner surface of the air intake cover can enhance the sound absorption effect in the midrange where the sound pressure level increases due to the noise of the blower. Efficiently low noise is realized.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a low noise device for a blower.
A blower 1 is housed in a state in which a rubber leg 3 for vibration isolation is attached in a housing 2 formed of a thick metal plate. The housing 2 has an intake port 4 communicating with the suction port of the blower 1 on the upper surface, and an air outlet 5 to which the blower port of the blower 1 is connected on one side surface. If necessary, a sound absorbing material may be attached to the inner surface of the housing 2 to enhance sound insulation. Further, in order to increase the intake efficiency, the intake ports 4 may be opened on a plurality of surfaces of the housing 2.

  A box-shaped intake cover 6 is attached to the intake port 4. The air intake cover 6 is attached to the upper surface of the housing 2, opens an air intake 7 directed to the side of the housing 2, and communicates the air intake 4 of the housing 2 with the air intake 7 of the air intake cover 6. The ventilation path 8 to be formed is formed. The ventilation path 8 not only functions as an intake path when the blower 1 is driven, but also functions as an exhaust heat path that promotes exhaust heat of the blower 1. In addition, the air intake cover 6 forms a sound absorbing layer 9 on the inner surface of the housing 2 facing the air inlet 4, and also plays a role of preventing the noise of the blower 1 from leaking outside.

  As shown in FIG. 2, the sound absorbing layer 9 is laminated in the order of the aluminum sintered material 10, the glass wool 11, and the air layer 12 from the air inlet 4 of the housing 2 to the inner wall of the air intake cover 6. The noise of the blower 1 that leaks linearly from the mouth 4 is absorbed. Specifically, the glass wool 11 is sandwiched and formed by the rib 13 for the space form suspended from the inner wall of the intake cover 6 and the aluminum sintered material 10.

  A sound absorbing tube 14 is connected to the blower outlet 5. The sound absorbing pipe 14 has a double structure of an inner cylinder 15 that communicates with the blowout port 5 and blows out air from the blower 1 and an outer cylinder 17 that is attached around the inner cylinder 15 with an air layer 16 interposed therebetween. None, it absorbs the noise of the blower 1 leaking through the outlet 5. Among these, the inner cylinder 15 is comprised from the aluminum sintered material, and the noise of an air blower is attenuated centering on a low frequency range by the aluminum sintered material and the back air layer 16, and the leakage to the outside is prevented.

  The low-noise device for a blower configured as described above is employed for a blower of a car wash machine, for example. In a car wash machine, it is used as a means for supplying air to a drying nozzle that blows high pressure air on the vehicle body to dry it, and a duct hose is connected to the tip of the inner cylinder 15 of the sound absorbing tube 14 to blow air to the nozzle.

Next, the sound absorbing action when using the blower will be described with respect to the examples.
Since the blower 1 is mounted in the housing 2 formed of a metal thick plate, noise reduction during driving is achieved. In addition, since the blower 1 is housed with the rubber feet for vibration isolation attached, it is reduced that the casing itself vibrates and becomes a noise source by driving the blower.

  The noise generated by the blower 1 is suppressed from leaking to the outside by the intake cover 6 and the sound absorption pipe 14 at the intake port 4 and the blowout port 5 of the housing 2, respectively. That is, noise from the air inlet 4 is absorbed by the sound absorbing layer 9 of the air intake cover 6, and noise from the air outlet 5 is absorbed by the inner cylinder 15. In the sound absorbing layer 9, sound absorption is achieved by energy conversion by the aluminum sintered material 10 and the glass wool 11 and a resonance effect by the air layer 12, and a uniform sound absorbing effect is exhibited for each sound range.

  Now, the sound absorbing effect for each sound range in the sound absorbing layer 9 is largely due to the thickness of the air layer 12. For example, as shown in FIG. 3, when the back air layer 12 of the glass wool 11 is set to 100 mm, the sound absorption rate for the mid-range of 300 to 1000 Hz increases (solid line), and when the back air layer 12 is set to 300 mm, 120 to 1000 Hz. The sound absorption rate for the low to mid range is increased (dotted line). Moreover, when the back air layer 12 of the aluminum sintered material 10 is set to 100 mm, the sound absorption coefficient for the mid-range of 400 to 1000 Hz is increased (one-dot broken line), and when the back air layer 12 is set to 50 mm, the high sound range of 1000 to 2000 Hz. Increases the sound absorption coefficient (double-dotted line).

  As shown in FIG. 4, the noise of the blower is distributed around 300 to 1000 Hz, and is particularly characterized by a high sound pressure level of 500 to 700 Hz (thick line). For this reason, by setting the thickness of the air layer 12 to 100 mm, it is possible to enhance the sound absorption effect in each sound range with respect to the noise of the blower. In addition, since the sound absorption effect by the combination of the sintered aluminum material 10 and the air layer 12 and the combination of the glass wool 11 and the air layer 12 is increased particularly in the mid-range of 400 to 1000 Hz, the sound pressure level is increased by the noise of the blower. It is possible to absorb sound mainly in the high mid range (thin line).

  Thus, since the sound absorbing layer 9 is formed on the inner surface of the air intake cover 6 facing the air inlet 4, it acts on the straight traveling wave from the sound source (blower) and efficiently reduces leakage to the outside. It becomes possible to do.

It is explanatory drawing which shows the low noise apparatus of an Example. 3 is an explanatory diagram showing a configuration of a sound absorbing layer 9. FIG. It is a graph which shows the sound-absorbing performance by a sound-absorbing material and a back air layer. It is a graph which shows the sound absorption effect of the air blower 1 by the sound absorption layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air blower 2 Housing | casing 4 Intake port 5 Outlet 6 Intake cover 8 Ventilation path 9 Sound absorption layer 10 Aluminum sintered material 11 Glass wool 12 Air layer

Claims (2)

In a low noise device for a blower in which a suction port and a blower outlet are opened in a housing in which the blower is installed, and at least a suction cover having a sound absorbing function is attached to the suction port.
The intake cover is attached to the suction port of the housing, forms a non-linear air passage that communicates the suction port of the housing with the outside air, and has an acoustic absorption characteristic on the inner surface facing the suction port of the housing. A low noise device for a blower, wherein a sound absorbing layer in which a plurality of different sound absorbing structures are laminated is formed.
2. The low noise apparatus for a blower according to claim 1, wherein the sound absorbing layer is formed in the order of aluminum sintered material, glass wool, and air layer from a noise source to an inner surface of the intake cover.

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