JPH062698A - Centrifugal blower - Google Patents

Abstract

PURPOSE:To restrain an increase of a pressure loss in an impeller, downsize a centrifugal blower, and reduce weight by arranging an opening part formed by notching the rear end side between blades of a main plate in the impeller of the centrifugal blower. CONSTITUTION:In this centrifugal blower, air sucked in from a suction port 2 according to rotation of a multiblade type impeller 1 flows toward the rear end side from the front end side between blades 3 of the impeller 1 while changing the direction along an inclination of a main plate 4, and is discharged in a casing 5. In this case, an opening part 6 formed by notching the rear end side between the blades 3 in the main plate 4 of the impeller 1, is arranged so that flowing resistance to a main flow is increased gradually according to a change of the main flow direction of the air and a pressure loss is not increased in the impeller 1. Thereby, an outside diametrical dimension (d) of the main plate 4 is set smaller than an outside diametrical demension D of the blades 3, and the rear end side between the blades 3 of the main plate 4 is opened, and an increase of the flowing resistance caused when the air flows between the blades 3 is restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal blower applied to blow or compress various gases. The centrifugal blower in this specification includes a centrifugal compressor.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view of a conventional centrifugal blower used for blowing, compressing and the like. In the figure, the multi-blade impeller 1 of the centrifugal blower is rotated so that the suction port 2
The air sucked from the air flows from the leading edge side to the trailing edge side between the blades 3 of the multi-blade impeller 1. This main flow of air flows while changing its direction along the inclination of the main plate 4 as shown by the arrow in the figure, and is discharged into the casing 5.

[0003]

In the conventional centrifugal blower as described above, the main flow of the air sucked from the suction port 2 changes its direction along the inclination of the main plate 4 of the multi-blade impeller 1 while changing the direction of the blades 3. While flowing from the leading edge side to the trailing edge side and discharged into the casing 5, the flow resistance to the main flow gradually increases as the main flow of air changes direction, and the pressure loss in the multiblade impeller 1 increases. Therefore, the amount of air discharged into the casing 5 is reduced. As a means for increasing the amount of air, there is a method such as increasing the outer diameter of the multiblade impeller 1 and the width between the blades 3. However, both of them increase the outer dimensions of the centrifugal blower and increase the weight. There is a problem such as.

[0004]

SUMMARY OF THE INVENTION A centrifugal fan according to the present invention is intended to solve the above-mentioned problems, and is characterized in that it is provided with an impeller having an opening formed by cutting out a trailing edge side between blades of a main plate. .

[0005]

That is, in the centrifugal blower according to the present invention, the impeller is provided with the opening notched on the trailing edge side of the main plate between the blades, and the gas flowing from the suction port into the impeller moves along the main plate between the blades. By flowing into the leading edge side and discharging a part of it into the casing from the opening provided on the trailing edge side, the flow resistance generated when the flow changes direction is not increased, and the pressure loss in the impeller is suppressed.

[0006]

1 and 2 are explanatory views of a centrifugal blower according to an embodiment of the present invention. In the figure, the centrifugal blower according to the present embodiment is used for air blowing, compression, etc., and the air sucked from the suction port 2 by the rotation of the multi-blade impeller 1 of the centrifugal blower is indicated by an arrow in the figure. As shown, the air flows in the casing 5 while changing its direction from the leading edge side to the trailing edge side between the blades 3 of the multi-blade impeller 1, and is discharged into the casing 5, but the main flow of air changes the direction. In order to prevent the flow resistance to the main flow from gradually increasing and the pressure loss in the multiblade impeller 1 to increase with the change, in the present centrifugal blower, as shown in FIG.
The trailing edge side between the blades 3 is cut out to form the opening 6, and the outer diameter dimension d of the main plate 4 is made smaller than the outer diameter dimension of the blade 3 to open the trailing edge side between the blades 3 of the main plate 4. It has a structure. In the drawing, reference numeral 1 is a multi-blade impeller of the centrifugal blower, 2 is a suction port, 3 is a blade, 4 is a main plate, 5 is a casing,
Reference numeral 6 denotes an opening formed by cutting out the trailing edge side between the blades 3 on the main plate 4. Further, D is the outer diameter dimension of the blade 3, d is the outer diameter dimension of the main plate 4, and in the present centrifugal blower d / D = 0.85.
In this case, the multiblade impeller 1 is installed.

As the multi-blade impeller 1 of the centrifugal blower rotates, the main flow of the air sucked from the suction port 2 is from the front edge side between the blades 3 along the inclination of the main plate 4 as shown by the arrow in the figure. Flows toward the trailing edge, part of which is the main plate 4
Since it is discharged into the casing 5 through the opening 6 on the trailing edge side, the main flow of the sucked air does not suddenly change its direction, and the flow resistance generated when the air flows between the blades 3 is increased. A small increase in pressure loss can be suppressed. Therefore, in the aerodynamic characteristics of the present centrifugal blower, as shown by the solid line in FIG. 2, the air volume increases by about 20% at 10,000 rpm rotation. As described above, in the centrifugal blower, the increase of the flow resistance in the multiblade impeller 1 is small,
Since the increase in pressure loss can be suppressed to a small level, problems such as an increase in the outer diameter size and an increase in the weight due to the increase in the air volume do not occur.

[0008]

The centrifugal blower according to the present invention is constructed as described above, and since the increase of the pressure loss in the impeller is suppressed, the outer diameter of the centrifugal blower does not increase and the weight does not increase. Can be increased.

[Brief description of drawings]

FIG. 1 (a) is a plan view of a multiblade impeller in a centrifugal blower according to an embodiment of the present invention, and FIG. 1 (b) is a sectional view.

FIG. 2 is an explanatory diagram of its operation.

FIG. 3 (a) is a plan view of a multi-blade impeller in a conventional centrifugal blower, and FIG. 3 (b) is a sectional view.

[Explanation of symbols]

 1 Multiblade Impeller 2 Suction Port 3 Blade 4 Main Plate 5 Casing 6 Opening

Claims (1)

[Claims] 1. A centrifugal blower comprising an impeller in which a main plate is provided with an opening formed by cutting out a trailing edge side between blades.