JPS61283800A - Silenced-type air blower - Google Patents

Abstract

PURPOSE:To reducing noise of low frequency ingredients, by setting up the air blower in the headline with a second box 2 at the discharge opening of an air blower housed in box 1 and a duct having a perforated portion provided in the box 2. CONSTITUTION:A box 18 is divided into two boxes 18A and 18B, and the box 18A which is provided therein with the casing 1 of an air blower and a motor 3 positioned via interposition of rubber vibration insulators 8. The second box 18B comprises a duct 20 penetrating its inner space and a perforated portion 21 of punched metal or the like, and a muffler consists of the duct 20 and the second box 18B. Thus, main low audio frequency ingredients can be silenced by virtue of effect of the muffler.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a noise-reducing blower used for air conditioning and ventilation of buildings.

BACKGROUND OF THE INVENTION In recent years, the demand for noise-reducing air blowers has been increasing year by year as there is an increasing demand for low-noise air conditioning and ventilation equipment in buildings.

The conventional noise-reducing air blower as described above will be described below with reference to the drawings.

FIG. 13 is a sectional view of a conventional noise-reducing blower.

In FIG. 3, reference numeral 1 denotes a blower casing which has an impeller 2 built therein. A motor 3 is connected to the impeller 2 by a belt 4. 5 is a common frame on which the blower casing 1 and motor 3 are attached. Reference character e is a box body that surrounds the entire blower casing 1, motor 3, and common frame 6, and the inner surface of this box is lined with a sound absorbing material 7 such as glass wool. The common frame 6 is attached to the box body 6 with vibration isolating rubber 8 interposed therebetween. 9 is a canvas attached to the discharge side of the blower casing 1, 1o is a suction port of the box body 6, 1
1 is a discharge port of the box body 6.

The operation of the noise-reducing air blower configured as described above will be described below.

First, when the moltre 3 is rotated, the blower impeller 2 rotates and the blowing action is started. Among the noises generated in this case, the noise from the suction side and the noise from the sides were to be reduced by the sound insulating effect of the box body 6 and the sound absorbing effect of the sound absorbing material attached to the inner surface.

Problems to be Solved by the Invention However, with the above configuration, the noise emitted from the discharge port 11 has no sound reduction effect at all, and therefore has the disadvantage that it is directly emitted into the connected duct, etc. Furthermore, even when countermeasures are taken on-site, since the noise contains many low-frequency components unique to blowers, the silencing device becomes large-scale, which poses problems in terms of cost and installation space.

In view of the above problems, the present invention focuses on the noise on the discharge side,
An object of the present invention is to provide a noise-reducing air blower having a structure that can effectively reduce low frequency components.

Means for Solving the Problems In order to solve the above-mentioned problems, the noise-reducing blower device of the present invention includes a blower rotated by a motor, and a first box surrounding the entire blower and having a sound-absorbing material pasted on the inner surface. The second box body is joined to the first box body, and a duct that penetrates the inside of the box body and has a part made of a perforated plate made of punched metal or the like.

Function: With this configuration, main low-frequency sound components of the noise on the discharge side are reduced by the sound reduction ability of the first second box body provided with the duct made of a perforated plate.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a cross section of a noise-reducing blower according to a first embodiment of the present invention. In Figure 1, 1 is a blower casing, 2 is an impeller, 3 is a motor, 4 is a belt,
Reference numeral 5 indicates a common frame, and reference numeral 9 indicates a campus, which are the same as the configuration shown in FIG. 3, and therefore their explanation will be omitted. 18 is a box body with internal partition plate 19! It is divided into 12 boxes 1aA and 1sH. The first box body 18A has the same structure as the conventional example shown in FIG. 3, and includes the blower casing 1. motor 3
A common pedestal 5 is provided inside and attached to the first box body 18A with a vibration isolating rubber 8 interposed therebetween. On the other hand, the second box body 1BB is made up of a duct 20 penetrating the inside and a perforated part 21 made of punched metal or the like provided in a part of the duct 20, and is expanded by this duct 2o and the second box body 18B. It constitutes a muffler. 22 is a suction port, and 23 is a discharge port.

The operation of the noise-reducing air blower configured as described above will be described below.

First, the motor 3 rotates and the impeller 2 rotates to start blowing air, and air enters through the suction port 22 and is blown through the discharge port 23. In this case, the suction port 22. A ventilation duct is connected to the discharge port 23. Of the noise generated from the blower at this time, the noise on the suction side and the side of the blower is reduced by the same effect as described in the conventional example. On the other hand, the noise on the discharge side enters the duct 20 inside the second box body 18B,
Due to the effect of the expansion type muffler constituted by the perforated portion 21 provided in this part and the second box body 18B, the main low frequency sound components are attenuated.

As described above, according to this embodiment, it is possible to reduce the main low-frequency sound component of the discharge side noise, which could not be reduced with conventional noise reduction equipment. It is possible to obtain the effect that there is no need for these devices, and that the installation space for them is no longer necessary. Furthermore, the sound leaking from the air duct connected to the noise-reducing air blower is also reduced by the noise on the main body side.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 12 is a cross-sectional view of a noise-muffling and blowing device showing a second embodiment of the present invention. In the figure, the same components as those in the first embodiment are designated by the same numbers and their explanations will be omitted. The difference from the configuration shown in FIG. 1 is that the boxes are two independent boxes 30 and 31, and their end faces 32 are shaped like seven-inches so that they can be joined. 33 is a tapping screw for joining.

The operation of the noise-reducing air blower configured as described above will be described below. As for the noise generated by the blower installed in the first box 3o, as in the first embodiment, the suction side noise and the blower side noise are reduced by the first box 3o, and the discharge noise is reduced by the independent blower. The sound is reduced by the muffler action of the box body 31 of No. 2. In this case, the expansion formed by the box body 31 of the tube 2 can be used to achieve the necessary sound reduction characteristics by changing the length L and the aperture ratio of the perforated portion shown in FIG. be able to.

As described above, according to this embodiment, since the main body is formed into two independent box bodies 30 and 31, the characteristics of the expansion type muffler are not fixed. For example, it is possible to install a fan that matches the noise characteristics when changing the rotation speed of the fan. It also becomes possible to retrofit it as a countermeasure against noise generated during on-site installation. Furthermore, by adding an expansion type muffler, so-called multi-stage use is possible.

In the second embodiment, the end surfaces of the boxes 30 and 31 are formed into flanges 32 and joined with tough screws 33, but this part may have other shapes (for example, an inset type), and the point is that the independent boxes are airtight. It would be good if it could be joined.

Effects of the Invention As described above, the present invention includes a second box body and a duct having a perforated portion provided in the first box body at the outlet of the blower housed in the first box body. This makes it possible to effectively reduce the low-frequency component, which is the main component of the noise from the blower's outlet, which could not be reduced with conventional noise-reducing blowers, and its practical effects are significant. There is.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a noise-reducing blower according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a noise-reducing blower according to a second embodiment of the present invention, and FIG. 3 is a conventional noise-reducing type blower. It is a sectional view of an air blower. 1...Blower casing, 3...Motor, 7...Sound absorbing material, 18A, 30...
・First box body, 18B. 31... Second box body, 2o... Duct, 21... Perforated part, 32... Flange part, 33... Tough pin screw. Figure 1 4q-+rTJJjAH---(77
゜2f-Perforated part Fig. 2 30-O1-Flower 0f---+ts a /---E&&Casing 2°-Impeller 3-Mo) Le cow---1-Rut 71 Slope Hit 8---- to the machine 9-11 camber/l+---1+亙(,.H--1υヱ士D

Claims (3)

[Claims] (1) A blower rotated by a motor, a first box that entirely surrounds the blower and has openings on both sides, and
a sound absorbing material affixed to the inner surface of a box, and a second box joined to an opening on the discharge side of the first box, penetrating the inside of the second box; A noise-reducing type air blower including a duct connected to the discharge port of the first box body, and a part of the duct being a perforated plate made of punched metal or the like. (2) The noise-reducing air blower according to claim 1, wherein the second box is detachably attached to the first box. (3) The noise-reducing air blower according to claim 2, wherein the second box body is also detachable from the suction side of the first box body.