JP3212040B2 - Centrifugal blower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal blower with reduced noise generation.

[0002]

2. Description of the Related Art When a coating film is formed on the blade surface of an impeller of a centrifugal blower, the roughness of the contact surface with the air flow is small and smooth, the air flow is easily biased, and the partial drift and swirl are remarkable. Likely to happen.

FIG. 7 is a side view of an impeller, FIG. 8 is a front view of a vane plate viewed from the R direction in FIG. 7, and FIG. 9 is a conceptual diagram of a blower. Show impeller 1
Is rotating in the direction of arrow D. X is the center line of the impeller, F
In the impeller having a smooth blade surface, the flow of air A is deviated as shown in FIGS. 8 and 9, and partial deflection and swirl are generated at locations indicated by a and b in FIG. It's easy to do. For this reason, the drawback that whistling noise is generated is unavoidable because the air is continuously pushed into the vicinity of the point where the drift or swirl occurs. Since the noise caused by the occurrence of the drift and the swirling is a high frequency of 2000 to 8000 Hz, the noise is a whistling sound due to transmission from the casing and emission from the discharge port.

[0004]

The generation of whistling noise caused by the continuous pushing of air near the point of occurrence of drift or swirl, which is a drawback of the prior art described above, is caused by the blades that come into contact with the air of the impeller. It has heretofore been proposed to make some modifications to the plate surface. However, an object of the present invention is to prevent the occurrence of a drift or a swirl which causes such noise without changing the structure of the centrifugal blower itself.

[0005]

SUMMARY OF THE INVENTION In the present invention, there is provided a centrifugal blower having an impeller with a resin-based thick film coating, coating, lining, etc. on the surface of the impeller. The problem is solved by adhering the granular material to the surface. With such a configuration, a centrifugal blower in which the generation of noise is reduced without increasing the surface roughness of the blades of the impeller and without changing the conventional structure itself is obtained.

[0006]

FIG. 1 is a partial perspective view of an impeller 1 of a centrifugal blower according to the present invention, and FIG.
The impeller 1 has a large number of blades 2, each of the blades 2 is coated with a coating film 3, and an adhesive 5
As a result, a large number of the granular materials 4 are adhered, and the surface roughness of the blade plate is increased.

FIG. 3 is a side view of the impeller according to the present invention, and FIG. 4 is a front view of the blades of FIG. FIG. 5 is a conceptual diagram of the centrifugal blower, in which the impeller 1 of the blower 10 rotates in the direction of arrow D, and the air A flows along the surface of the blade 2.
It flows in the direction of arrow F.

In the present invention, since the roughness of the blade surface is increased, the air flows between the irregularities on the blade surface, so that the flow is not biased and the distribution of the flow is reduced as shown in FIGS. Uniformity, no drift, swirl, etc. are generated, and no whistling sound (singular sound) is generated around the points indicated by a and b in the figure.

FIG. 6 is a graph comparing the centrifugal blower of the present invention with a solid line and the conventional one with a broken line, with frequency Hz on the horizontal axis and noise level dB (A) on the vertical axis. It is shown that the noise is significantly reduced in the high frequency range. (50-80, 100-
One of the octave bands of 160, 200-315, ...
The horizontal axis is the frequency at / 3. )

[0010]

The centrifugal blower according to the present invention has the above-described structure, and increases the roughness of the blade plate surface to prevent the air flow from being unbalanced. The sound dropped and the peculiar whistling sound disappeared.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of an impeller of the present invention.

FIG. 2 is a sectional view of a blade.

FIG. 3 is a side view of the impeller.

FIG. 4 is a front view of the vane plate when FIG. 3 is viewed from an R direction.

FIG. 5 is a conceptual diagram of a blower.

FIG. 6 is a comparison diagram of noise levels.

FIG. 7 is a side view of a conventional impeller.

FIG. 8 is a front view of the vane plate when FIG. 7 is viewed from the R direction.

FIG. 9 is a conceptual diagram of a blower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller 2 Blade plate 3 Coating film 4 Granular material 5 Adhesive 10 Centrifugal blower

Claims (1)

(57) [Claims] 1. A centrifugal blower having an impeller with a resin-based thick film coating, coating, lining, etc. on the surface of a blade, wherein a granular material is adhered to the surface of the blade of the impeller. Blower.