JPH11141499A - Impeller and multiblade centrifugal fan using this impeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the draft resistance on the disc side of a passage between blades to improve the air capacity performance by setting the length of the warp line of a blade shorter in a disc-side edge than in an annular part-side edge, and specifying the relation between the number of blades and the average of the outer diameter of the disk and the outer diameter of the ring part. SOLUTION: The side opposite to a disc 1 of a blade 3 is fixed by a ring 2, so that the central axis-side edge of the blade 3 is substantially vertical to the disc 1, and the length of the warp line of the blade 3 is set shorter in the disc-side edge than in the ring plate-side edge. According to this, the passage length in the disc-side area of a passage between blades is reduced. When the number of blades is N, and the average of the outer diameter of the disc and the outer diameter of the ring part is D1 , the value of N/D1 is preferably set to 0.4 or more because the air capacity performance is deteriorated when the draft resistance is high with less than 0.4. Thus, the draft resistance can be reduced to improve air the capacity performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller of a multi-blade centrifugal fan.

[0002]

2. Description of the Related Art A conventional technique of this kind is disclosed in
No. 284886. This will be described below with reference to FIG.

[0003] The impeller of the multi-blade centrifugal fan includes a disk 31 and an annular plate 32 disposed concentrically and concentrically with the disk 31.
And a plurality of rectangular blades 33 disposed at intervals in the circumferential direction between the circular plate 31 and the circular plate 32,
The inner peripheral edge of the annular plate 32 is positioned radially outward from the radially inner end of the blade 33.

[0004] With the above configuration, an attempt is made to increase the suction amount of the fluid and to suppress the separation of the fluid on the annular plate side of the flow path between the blades.

[0005]

However, in the above-mentioned conventional construction, the radial length of the blade is equal on the annular plate side and the disk side, so that the disk side having the highest ventilation resistance in the flow path between the blades. Has a problem that the flow path length is relatively long and the ventilation resistance in this region is high.

SUMMARY OF THE INVENTION The present invention solves such a conventional problem, in which the length of the sled line of the blade is made shorter on the side of the disk than on the side of the annular portion, and the flow between the blades is reduced. It is an object of the present invention to provide a multi-blade centrifugal fan having improved air volume performance by reducing ventilation resistance on the disk side of a road.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a disk, an annular portion arranged concentrically and parallel to the disk and having an outer diameter larger than that of the disk; A plurality of blades are provided radially between the circular plate and the annular portion with respect to a central axis connecting the center of the plate and the center of the annular portion, and the side of the central axis side of the blade is circular. The blade is substantially perpendicular to the plate, the length of the sled line of the blade is set to be shorter on the disk side than on the ring side, and the number of blades is N, the outer diameter of the disk and the ring when the average outer diameter of the part and the D _1, the relationship between the N and D ₁ is 0.4 ≦ N /
It is obtained as a D _1.

By making the shape of the blade so that the side on the disk side is shorter than the side on the annular portion side, the flow path length in the disk side region of the flow path between the blades is reduced, and the ventilation resistance is reduced. Decrease
A multi-blade centrifugal fan with improved air volume performance can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is characterized in that a circular plate, an annular portion arranged concentrically and parallel to the circular plate and having an outer diameter larger than that of the circular plate, a center of the circular plate, A plurality of blades radially arranged between the circular plate and the annular portion with respect to a central axis connecting the center of the circular portion, and a side of the central axis side of the blade with respect to the circular plate; It is assumed to be substantially vertical, the length of the sled line of the blade is made shorter on the disk side than on the ring side, and the number of blades is N, the outer diameter of the disk and the outer diameter of the annular portion mean when was the D ₁ of the one in which the relationship between the N and D ₁ is set to be 0.4 ≦ N / D _1. According to this configuration, the flow path length in the disk-side region of the flow path between the blades is shortened, and the ventilation resistance can be reduced.

According to a second aspect of the present invention, there is provided the impeller according to the first aspect, and a casing for accommodating the impeller.
The inner diameter D _i of the inlet of the casing or less equal to the internal diameter D ₂ of the impeller, and when the number of blades N, the average outer diameter of the annular portion of the disc and D _1, N and D 0.4 ≦ N with relation to ₁
It is obtained by the / D ₁ and becomes like. According to this configuration, turbulence in the suction section can be reduced, and noise can be reduced.

According to a third aspect of the present invention, the end portion of the suction portion of the casing is folded back toward the impeller, so that the shape is widened toward the outer peripheral direction of the impeller. Flow can be reduced and noise can be reduced.

According to a fourth aspect of the present invention, the number of blades is N,
When the average outer diameter of the annular portion of the disc was D _1, N
Centrifugal fan in which the relationship between D and D ₁ is 0.4 ≦ N / D ₁ , wherein the blades are arranged such that the outer peripheral angle β ₂ of the blades is 60 ° ≦ β ₂ ≦ 90 °. To prevent peeling at
Noise can be reduced and air volume performance can be improved.

According to a fifth aspect of the present invention, the number of blades is N,
When the average of the outer diameter of the disk and the outer diameter of the annular portion is D ₁ and the inner diameter of the impeller is D ₂ , in a centrifugal fan in which the relationship between N and D ₁ is 0.4 ≦ N / D ₁ , Inner / outer diameter ratio of impeller D ₂ / D ₁
Are arranged such that 0.5 ≦ D ₂ / D ₁ ≦ 0.8. Therefore, it is possible to suppress an increase in ventilation resistance due to an increase in the flow path length, and to improve the air volume performance.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIG. 1, a disc 1, an annular ring 2 arranged concentrically and parallel to the disc 1 and having an outer diameter larger than that of the disc 1, and a center of the disc 1 A plurality of blades 3 radially arranged on the disk 1 with respect to a center axis connected to the center of the ring 2, and a side opposite to the disk 1 side of the blade 3 by the ring 2. The blade 3 is fixed so that the side on the central axis side of the blade 3 is substantially perpendicular to the disk 1, and the length of the sled line of the blade 3 is shorter on the disk side than on the ring plate side. I do. As a result, the flow path length in the disk-side region of the flow path between the blades is shortened,
The ventilation resistance can be reduced, and the air volume performance can be improved.

In the above description, the case where the ring 2 is used has been described. However, as shown in FIG. 1 (c), the side opposite to the disk 1 side of the blade 3 using the ring plate 4 is used. It may be fixed.

FIG. 2 shows characteristic curves of static pressure and noise with respect to the flow rate of the multiblade centrifugal fan when the number of blades is changed.
The number of blades is N, and the average of the outer diameter of the disk and the outer diameter of the annular portion is D ₁
When the value of N / D ₁ is less than 0.4, the air volume performance deteriorates when the ventilation resistance is large. Therefore, N / D ₁
Is desirably 0.4 or more.

(Embodiment 2) In FIG. 3, an outer peripheral end of a plurality of blades 12 radially arranged on the disk 11 with respect to the center is fixed with a ring 13 on the side opposite to the disk 11. The inner diameter D _i of the suction port 15 of the casing 14 accommodating the impeller is smaller than or equal to the inner diameter D ₂ of the impeller. Thereby, turbulence in the suction portion of the casing can be reduced, and noise can be reduced. Further, air volume performance deteriorates when the inner diameter D _i of the inlet 15 of the casing 14 is larger than the inner diameter D ₂ of the impeller. Therefore, the value of D _i may be desirable to below equal to D _2.

In the above description, the case where an annular ring is used has been described, but the blade 1 is formed by using a thin annular plate.
Even if the outer peripheral end of 2 is fixed on the opposite side to the disk 11,
Similar effects can be obtained.

(Embodiment 3) In FIG. 4, the disk 1 at the outer peripheral ends of a plurality of blades 12 radially arranged on the disk 11 is shown.
1 is an inner diameter D of an impeller having an opposite side fixed by a ring 13
₂ and compared, arranged as the inner diameter D _i of the inlet of the casing 14 is equal to or less. Suction part 21 of casing 14
Is folded back toward the impeller, and expands toward the outer periphery of the impeller. Thereby, turbulence in the suction portion of the casing can be reduced, and noise can be reduced.

(Embodiment 4) FIG. 5 shows the definition of the outer peripheral angle used here. Here, the outer peripheral angle is an angle between a tangent of the outer periphery and a tangent of the center line of the blade at a point where the blade contacts the outer periphery of the impeller.

FIG. 6 shows characteristic curves of static pressure and noise with respect to the flow rate of the forward-facing multi-blade centrifugal fan when the outer peripheral angle of the blade is changed. In the forward multi-blade centrifugal fan, the outer peripheral angle β
_{When 2} satisfies 90 ° <β ₂ , the noise rises sharply when the ventilation resistance is large, and the air flow decreases when 0 ° <β ₂ <60 °. For this reason, if the blades are arranged so that the outer peripheral angle β ₂ satisfies 60 ° ≦ β ₂ ≦ 90 °, good performance can be obtained in both air volume performance and noise.

(Embodiment 5) FIG. 7 shows characteristic curves of static pressure and noise with respect to the flow rate of a forward-facing multi-blade centrifugal fan when the inner-outer diameter ratio of the impeller is changed. In prospective multiblade centrifugal fan, the diameter ratio D ₂ / D ₁ is 0.8 <D ₂ / D _1, the noise is rapidly increased when the ventilation resistance is large, D ₂
When / D ₁ <0.5, the air volume decreases. Therefore, diameter ratio D ₂ / D ₁ can be obtained when disposing the blade such that _{0.5 ≦ D 2 / D 1 ≦} 0.8, air flow performance, noise with a good performance.

[0024]

As is apparent from the above embodiment, according to the first aspect of the present invention, the length of the sled line of the blade is made shorter on the disk side than on the ring side. And the number of blades is N, and the average of the outer diameter of the disk and the outer diameter of the annular portion is D ₁
In this case, the relationship between N and D ₁ is set to satisfy 0.4 ≦ N / D _1, and according to this configuration, the flow path length in the disk-side region of the flow path between the blades is reduced. Since the length becomes shorter and the ventilation resistance is reduced, there is an effect that the air volume performance can be improved.

According to a second aspect of the present invention, the inside diameter of the suction port of the casing is equal to or less than the inside diameter of the impeller, and a plurality of blades of the impeller are fixed by an annular portion. Turbulence generated in the suction portion of the casing can be reduced. Thereby, a low noise effect can be obtained.

According to a third aspect of the present invention, the end of the suction portion of the casing is folded back toward the impeller and extends toward the outer periphery of the impeller. This has the effect of reducing turbulence at the point and reducing noise.

According to a fourth aspect of the present invention, based on the experimental results, the blades are arranged so that the outer peripheral angle β ₂ satisfies 60 ° ≦ β ₂ ≦ 90 °. There is an effect that good performance can be obtained in both performance and noise.

According to a fifth aspect of the present invention, based on the experimental results, the inner / outer diameter ratio D ₂ / D ₁ is 0.5 ≦ D ₂ / D ₁ ≦ 0.8.
With this configuration, there is an effect that good performance can be obtained in both air volume performance and noise.

[Brief description of the drawings]

FIG. 1A is a plan view of a multi-blade centrifugal fan showing one embodiment of the present invention. FIG. 1B is a cross-sectional view of a multi-blade centrifugal fan showing one embodiment of the present invention. Sectional view of a multi-blade centrifugal fan showing another embodiment

FIG. 2 is a characteristic curve diagram of static pressure and noise with respect to a flow rate when the number of blades of a multi-blade centrifugal fan according to an embodiment of the present invention is changed.

FIG. 3 is a cross-sectional view of a multi-blade centrifugal fan showing another embodiment of the present invention.

FIG. 4 is a sectional view of a multi-blade centrifugal fan showing still another embodiment of the present invention.

FIG. 5 is an explanatory view showing a definition of an outer peripheral angle in the present invention.

FIG. 6 is a characteristic curve diagram of a static pressure and a noise with respect to a flow rate when an outer peripheral angle of a blade of a multi-blade centrifugal fan according to still another embodiment of the present invention is changed.

FIG. 7 is a characteristic curve diagram of a static pressure and a noise with respect to a flow rate when an inner / outer diameter ratio of an impeller of a multi-blade centrifugal fan is changed according to still another embodiment of the present invention.

8A is a plan view of a conventional multi-blade centrifugal fan. FIG. 8B is a cross-sectional view of the conventional multi-blade centrifugal fan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disk 2 Ring 3 Blade 4 Ring plate 14 Casing 15 Casing suction port 21 Casing suction part

Claims (5)

[Claims] 1. A disk, an annular portion arranged concentrically and parallel to said disk and having an outer diameter larger than said disk, and a center of said disk and a center of said annular portion. A plurality of blades radially disposed between the circular plate and the annular portion with respect to the tied central axis, wherein a side of the central axis side of the blade is substantially perpendicular to the circular plate; The length of the sled line of the blade is made shorter on the side of the disk than on the side of the annular portion, and the number of blades is N, the outer diameter of the disk and the length of the annular portion. when the average of outer diameter is D _1, the relationship between the N and D ₁ is 0.4
≦ N / D ₁ . [2 claim] and the impeller of claim 1, it comprises a casing for housing the impeller, with the inner diameter D _i of the inlet of the casing is equal to or less than the internal diameter D ₂ of the impeller, and the vane when the number N, the average outer diameter between the outer diameter of the disc the annular portion and the D _1, the relationship between the N and D ₁ is 0.4 ≦ N /
Multiblade centrifugal fan, characterized in that a D _1. 3. The multi-blade centrifugal fan according to claim 2, wherein the end of the suction portion of the casing is folded back toward the impeller and extends toward the outer periphery of the impeller. Wherein when the number of blades N, the average outer diameter of the annular portion of the disc was D _1, relationship 0.4 ≦ N and D ₁
N / D ₁ and the outer peripheral angle β ₂ of the blade is 60 ° ≦ β
An impeller, wherein the blades are arranged so that ₂ ≦ 90 °. 5. When the number of blades is N, the average of the outer diameter of the disk and the outer diameter of the annular portion is D ₁ , and the inner diameter of the impeller is D ₂ , N and D ₁
With the relationship of 0.4 ≦ N / D _1, and the blades are arranged such that the inner / outer diameter ratio D ₂ / D ₁ of the impeller is 0.5 ≦ D ₂ / D ₁ ≦ 0.8. An impeller characterized by being provided.