FAN BLADES

Abstract

A blade for an axial fan, including at least a front edge portion, a back edge portion, and multiple pressure balance holes. The front edge portion operates to blow air from the outside of the blade, the back edge portion operates to blow air to the outside of the blade, and the pressure balance hole is disposed on the back edge portion. The pressure balance holes are adapted to balance pressure and reduce pressure difference between the front side and the back side of the blade, eliminating backflow phenomenon caused by separation of boundary layer airflow at the back edge portion on a windward side of the blade and thus reducing power consumption and noise, and preventing dust from settling on the back edge portion on the windward side of the blade.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. §119 and the Paris Convention Treaty, this application claims the benefit of Chinese Patent Application No. 200810187034.0 filed on Dec. 11, 2008, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a blade for an axial fan and a blade for a centrifugal fan.

2. Description of the Related Art

As shown in FIG. 1, a conventional blade for an axial fan comprises a front edge portion and a back edge portion. The front edge portion operates to blow air from the outside of the blade, and the back edge portion operates to blow air to the outside of the blade. However, there are several problems with the blade: as the blade rotates, the airflow at the back edge portion is affected with increase of rotary kinetic energy, as a result, separation of boundary layer airflow causes a backflow phenomena when the airflow is discharged from the back edge portion, which increases power consumption and noise, and a great deal of dust is settled on the back edge portion on a windward side of the blade.

As for a conventional blade for a centrifugal fan, the same problems as above exist.

SUMMARY OF THE INVENTION

In view of the above-described problem, it is one objective of the invention to provide a conventional blade for an axial fan that is capable of eliminating a backflow phenomena caused by separation of boundary layer airflow, reducing power consumption and noise, and preventing dust from being settled on a back edge portion on a windward side of the blade.

It is another objective of the invention to provide a conventional blade for a centrifugal fan that is capable of eliminating a backflow phenomena caused by separation of boundary layer airflow, reducing power consumption and noise, and preventing dust from being settled on a back edge portion on a windward side of the blade.

To achieve the above objectives, in accordance with one embodiment of the invention, provided is a blade for an axial fan, comprising a front edge portion, a back edge portion, and multiple pressure balance holes. The front edge portion operates to blow air from the outside of the blade, the back edge portion operates to blow air to the outside of the blade, and the pressure balance hole is disposed on the back edge portion.

In a class of this embodiment, the pressure balance holes are distributed in an array, uniformly or randomly.

In a class of this embodiment, the pressure balance holes are straight through holes or inclined through holes.

In a class of this embodiment, the pressure balance holes form a hole net whereby adjusting pressure on both side of the blade.

In a class of this embodiment, a diameter of the pressure balance hole ranges from 0.1 mm to 100 mm.

In a class of this embodiment, the pressure balance hole is a circular hole or a non-circular hole.

In accordance with another embodiment of the invention, provided is a blade for a centrifugal fan, comprising a front edge portion, a back edge portion, and multiple pressure balance holes. The front edge portion operates to blow air from the outside of the blade, the back edge portion operates to blow air to the outside of the blade, and the pressure balance hole is disposed on the back edge portion.

In a class of this embodiment, the pressure balance holes are distributed in an array, uniformly or randomly.

In a class of this embodiment, the pressure balance holes are straight through holes or inclined through holes.

In a class of this embodiment, the pressure balance holes form a hole net whereby adjusting pressure on both side of the blade.

In a class of this embodiment, a diameter of the pressure balance hole ranges from 0.1 mm to 100 mm.

In a class of this embodiment, the pressure balance hole is a circular hole or a non-circular hole.

Advantages of the blade for an axial fan of the invention comprise: 1) the pressure balance holes disposed on the back edge portion are capable of balancing pressure and reducing pressure difference between a front side and a back side of the blade; 2) the pressure balance holes are capable of eliminating a backflow phenomena caused by separation of boundary layer airflow at the back edge portion on a windward side of the blade and thus reducing power consumption and noise; 3) the pressure balance holes are capable of preventing dust from being settled on a back edge portion on a windward side of the blade.

Advantages of the blade for a centrifugal fan of the invention comprise: 1) the pressure balance holes disposed on the back edge portion are capable of balancing pressure and reducing pressure difference between a front side and a back side of the blade; 2) the pressure balance holes are capable of eliminating a backflow phenomena caused by separation of boundary layer airflow at the back edge portion on a windward side of the blade and thus reducing power consumption and noise; 3) the pressure balance holes are capable of preventing dust from being settled on a back edge portion on a windward side of the blade.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinafter with reference to accompanying drawings, in which:

FIG. 1 is a schematic view of an axial fan in the prior art;

FIG. 2 is a schematic view of a blade for an axial fan of an exemplary embodiment of the invention;

FIG. 3 illustrates an application of an axial fan of an exemplary embodiment of the invention;

FIG. 4 is a schematic view of a centrifugal fan of another exemplary embodiment of the invention; and

FIG. 5 is a schematic view of a blade for a centrifugal fan of another exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

As shown in FIGS. 2 and 3, a blade for an axial fan of the invention comprises a front edge portion 1, a back edge portion 2, and multiple pressure balance holes 3. The front edge portion 1 operates to blow air from the outside of the blade, the back edge portion 2 operates to blow air to the outside of the blade, and the pressure balance hole 3 is disposed on the back edge portion 2.

The pressure balance holes 3 are distributed in an array, uniformly or randomly.

In this embodiment, the pressure balance holes 3 are circular holes, non-circular holes, straight through holes or inclined through holes, and a diameter of each of the pressure balance holes 3 ranges from 0.1 mm to 100 mm.

The pressure balance holes 3 form a hole net whereby adjusting pressure on both side of the blade.

The pressure balance holes 3 are capable of balancing pressure and reducing pressure difference between a front side and a back side of the blade, eliminating a backflow phenomena caused by separation of boundary layer airflow at the back edge portion 2 on a windward side 4 of the blade and thus reducing power consumption and noise, and preventing dust from being settled on the back edge portion 2 on the windward side 4 of the blade.

As shown in FIGS. 4 and 5, a blade for a centrifugal fan of the invention comprises a front edge portion 1, a back edge portion 2, and multiple pressure balance holes 3. The front edge portion 1 operates to blow air from the outside of the blade, the back edge portion 2 operates to blow air to the outside of the blade, and the pressure balance hole 3 is disposed on the back edge portion 2.

The pressure balance holes 3 are distributed in an array, uniformly or randomly.

In this embodiment, the pressure balance holes 3 are circular holes, non-circular holes, straight through holes or inclined through holes, and a diameter of each of the pressure balance holes 3 ranges from 0.1 mm to 100 mm.

The pressure balance holes 3 form a hole net whereby adjusting pressure on both side of the blade.

The pressure balance holes 3 are capable of balancing pressure and reducing pressure difference between a front side and a back side of the blade, eliminating a backflow phenomena caused by separation of boundary layer airflow at the back edge portion 2 on a windward side 4 of the blade and thus reducing power consumption and noise, and preventing dust from being settled on the back edge portion 2 on the windward side 4 of the blade.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims

1. A blade for an axial fan, comprising a front edge portion;a back edge portion; andmultiple pressure balance holes; whereinsaid front edge portion operates to blow air from the outside of the blade;said back edge portion operates to blow air to the outside of the blade; andsaid pressure balance hole is disposed on said back edge portion.

2. The blade of claim 1, wherein said pressure balance holes are distributed in an array, uniformly or randomly.

3. The blade of claim 1, wherein said pressure balance holes are circular holes, non-circular holes, straight through holes or inclined through holes.

4. The blade of claim 1, wherein said pressure balance holes form a hole net whereby adjusting pressure on both side of the blade.

5. The blade of claim 1, wherein a diameter of said pressure balance hole ranges from 0.1 mm to 100 mm.

6. The blade of claim 1, wherein said pressure balance hole is a circular hole or a non-circular hole.

7. A blade for a centrifugal fan, comprising a front edge portion;a back edge portion; andmultiple pressure balance holes; whereinsaid front edge portion operates to blow air from the outside of the blade;said back edge portion operates to blow air to the outside of the blade; andsaid pressure balance hole is disposed on said back edge portion.

8. The blade of claim 7, wherein said pressure balance holes are distributed in an array, uniformly or randomly.

9. The blade of claim 7, wherein said pressure balance holes are circular holes, non-circular holes, straight through holes or inclined through holes.

10. The blade of claim 7, wherein said pressure balance holes form a hole net whereby adjusting pressure on both side of the blade.

11. The blade of claim 7, wherein a diameter of said pressure balance hole ranges from 0.1 mm to 100 mm.

12. The blade of claim 7, wherein said pressure balance hole is a circular hole or a non-circular hole.