U.S. patent application number 09/759501 was filed with the patent office on 2002-07-18 for axial flow fan structure.
Invention is credited to Liao, William C., Yeuan, Jian J..
Application Number | 20020094271 09/759501 |
Document ID | / |
Family ID | 25055886 |
Filed Date | 2002-07-18 |
United States Patent
Application |
20020094271 |
Kind Code |
A1 |
Yeuan, Jian J. ; et
al. |
July 18, 2002 |
Axial flow fan structure
Abstract
The present invention provides an axial flow fan structure
having an optimal airflow rate and pressure head. The axial flow
fan structure includes a rotor provided with a plurality of fan
blades which are overlapped with each other. In such a manner,
variations of the chord angle, the air inlet angle, and the air
outlet angle of the fan blade together with adjustment of the span
of the fan blades co-operate with rotation of the fan blade to
produce an optimal airflow rate and pressure head. In addition, the
fan blades of the rotor may co-operate with a set of stator guide
vanes, thereby further increase the pressure head of the airflow,
while the airflow having a high flow rate and high pressurization
is guided to a predetermined direction more efficiently.
Inventors: |
Yeuan, Jian J.; (Taichung
City, TW) ; Liao, William C.; (Taichung City,
TW) |
Correspondence
Address: |
Charles E. Baxley
Hart, Baxley, Daniels & Holton
Fifth Floor
59 John Street
New York
NY
10038
US
|
Family ID: |
25055886 |
Appl. No.: |
09/759501 |
Filed: |
January 16, 2001 |
Current U.S.
Class: |
415/208.2 ;
415/211.2; 415/220; 416/183; 416/188; 416/223R; 416/238;
416/243 |
Current CPC
Class: |
F04D 29/325 20130101;
F04D 25/0613 20130101; F04D 19/002 20130101 |
Class at
Publication: |
415/208.2 ;
415/211.2; 415/220; 416/183; 416/188; 416/223.00R; 416/238;
416/243 |
International
Class: |
F04D 019/00; F04D
029/38 |
Claims
What is claimed is:
1. An axial flow fan structure comprising: a rotor (20) provided
with a plurality of fan blades (21), each of said fan blades (21)
including a chord angle ("A"), an air inlet angle ("B"), and an air
outlet angle ("C"), variations of said chord angle ("A"), said air
inlet angle ("B"), and said air outlet angle ("C") of said fan
blade (21) co-operate with rotation of said fan blade (21) to
produce a pressurized airflow rate; wherein, said fan blades (21)
are arranged in a head-tail overlap arrangement manner with each
other, so that more fan blades (21) may be arranged in said axial
flow fan structure in a head-tail overlap arrangement manner of
said fan blades (21), an overlap distance ("D") of said fan blades
(21) is greater than zero and smaller than one third of a blade
average distance ("E"), said chord angle ("A") of each of said fan
blades (21) is ranged between twenty degrees and sixty degrees, and
said overlapped fan blades (21) have an action surface while the
total action area is increased to co-operate with said chord angle
("A") of each of said fan blades (21), for generating a higher
airflow rate and total pressure head with the greatest
efficiency.
2. An axial flow fan structure comprising: a rotor (20) provided
with a plurality of fan blades (21), each of said fan blades (21)
including a chord angle ("A"), an air inlet angle ("B"), and an air
outlet angle ("C"), variations of said chord angle ("A"), said air
inlet angle ("B"), and said air outlet angle ("C") of said fan
blade (21) co-operate with rotation of said fan blade (21) to
produce a pressurized airflow rate; wherein, said fan blades (21)
are arranged in a head-tail overlap arrangement manner with each
other, a set of stator guide vanes (31), are sealingly mounted on a
predetermined airflow direction side of said fan blades (21), each
of said stator guide vanes (31) includes a chord angle ("a"), an
air inlet angle ("b"), and an air outlet angle ("c"), and
variations of said chord angle ("a"), said air inlet angle ("b"),
and said air outlet angle ("c") of said stator guide vane (31)
further increase a pressurization of said pressurized airflow rate,
while said airflow having a high flow rate and pressure head can be
guided more efficiently to a predetermined direction.
3. The axial flow fan structure in accordance with claim 2, wherein
said stator guide vane (31) has a configuration that can be
adjusted according to a requirement of a generated airflow rate of
said rotor (20).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an axial flow fan
structure, and more particularly to an axial flow fan structure
which has the optimal airflow rate and pressure head.
[0003] 2. Description of the Related Prior Art
[0004] A conventional axial flow fan 10 in accordance with the
prior art shown in FIG. 1 comprises a plurality of blades 11 that
are separate from each other, and are not overlapped with each
other. However, the conventional axial flow fan 10 has the
following disadvantages.
[0005] 1. The blades 11 are separate from each other with a large
space 12 defined therebetween, so that the number of the blades 11
that may be mounted on the conventional axial flow fan 10 is
greatly limited. Therefore, the action surfaces of the smaller
number of blades 11 cannot provide a sufficient pressurization to
the space 12 between two adjacent blades 11, so that the
conventional axial flow fan 10 does not efficiently provide the
airflow rate in the spaces 12.
[0006] 2. After the blade 11 of the conventional axial flow fan 10
has exerted pressure on the space 12, the space 12 is pressed by
the action surface of the blade 11, so that the airflow rate in the
space 12 will produce an airflow rate with the flow movement in the
tangent direction and the normal direction. The space 12 is larger,
but the action curve of the blade 11 is not sufficient, so that the
conventional axial flow fan 10 cannot increase the pressurization
of the airflow rate.
SUMMARY OF THE INVENTION
[0007] The primary objective of the present invention is to provide
an axial flow fan structure having an optimal airflow rate and
pressure head. The axial flow fan structure includes a rotor
provided with a plurality of fan blades which are overlapped with
each other so as to increase the total action area of the
overlapping blade action surface, thereby producing the optimal
airflow rate with the greatest total pressure head.
[0008] Another objective of the present invention is to provide an
axial flow fan structure having a smaller loss of pressure head.
The fan blades of the rotor may co-operate with a set of stator
guide vanes, thereby further increasing the pressurization of the
airflow rate, while the fan having a high flow rate and high
pressurization is guided to a predetermined direction more
efficiently, thereby decreasing the loss of pressure head.
[0009] In accordance a first embodiment of with the present
invention, there is provided an axial flow fan structure
comprising: a rotor provided with a plurality of fan blades, each
of the fan blades including a chord angle, an air inlet angle, and
an air outlet angle, variations of the chord angle, the air inlet
angle, and the air outlet angle of the fan blade co-operate with
rotation of the fan blade to produce a pressurized airflow rate;
wherein, the fan blades are arranged in a head-tail overlap
arrangement manner with each other, so that more fan blades may be
arranged in the axial flow fan structure in a head-tail overlap
arrangement manner of the fan blades, an overlap distance of the
fan blades is greater than zero and smaller than one third of a
blade average distance, the chord angle of each of the fan blades
is ranged between twenty degrees and sixty degrees, and the
overlapped fan blades have an action surface whose total action
area is increased to co-operate with the chord angle of each of the
fan blades, for generating an airflow rate with the greatest
efficiency.
[0010] In accordance a second embodiment of with the present
invention, there is provided an axial flow fan structure
comprising: a rotor provided with a plurality of fan blades, each
of the fan blades including a chord angle, an air inlet angle, and
an air outlet angle, variations of the chord angle, the air inlet
angle, and the air outlet angle of the fan blade co-operate with
rotation of the fan blade to produce a pressurized airflow rate;
wherein, the fan blades are arranged in a head-tail overlap
arrangement manner with each other, a set of stator guide vanes,
are sealingly mounted on a predetermined flow direction side of the
fan blades, each of the stator guide vanes includes a chord angle,
an air inlet angle, and an air outlet angle, and variations of the
chord angle, the air inlet angle, and the air outlet angle of the
stator guide vane further increase a pressurization of the
pressurized airflow rate, while the airflow rate having a high flow
rate can be guided more efficiently to a predetermined direction
with the best recovery of pressure head.
[0011] Further benefits and advantages of the present invention
will become apparent after a careful reading of the detailed
description with appropriate reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a front plan view of a conventional axial flow fan
in accordance with the prior art;
[0013] FIG. 2 is a perspective view of an axial flow fan structure
in accordance with a first embodiment of the present invention;
[0014] FIG. 3 is a front plan view of the axial flow fan structure
as shown in FIG. 2;
[0015] FIG. 4 is a partially cut-away perspective cross-sectional
view of an axial flow fan structure in accordance with a second
embodiment of the present invention;
[0016] FIG. 5 is a front plan cross-sectional view of the axial
flow fan structure as shown in FIG. 4;
[0017] FIG. 6 is a schematic view of fan blades and stator guide
vanes of the axial flow fan structure as shown in FIG. 4; and
[0018] FIG. 7 is a graph of experimental results of the axial flow
fan structure in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring to the drawings and initially to FIGS. 2 and 3, an
axial flow fan structure in accordance with a first embodiment of
the present invention comprises a rotor 20 that is driven by an
electrical motor and/or driving devices to rotate axially, and is
provided with a plurality of fan blades 21. The fan blades 21 are
arranged in a head-tail overlap arrangement manner with each other,
that is, the head of one fan blade 21 overlaps with the tail of the
adjacent fan blade 21. By means of the head-tail overlap
arrangement manner of the fan blades 21, the periphery of the rotor
20 of the axial flow fan structure may be provided with more fan
blades 21, more front spaces 23, and more action surfaces 22 of the
fan blades 21.
[0020] Each of the fan blades 21 includes a chord angle "A", an air
inlet angle "B", and an air outlet angle "C", wherein variations of
the chord angle "A", the air inlet angle "B", and the air outlet
angle "C" of the fan blade 21 together with the overlap distance
"D" of the fan blades 21 may co-operate with rotation of the fan
blades 21 to produce a predetermined pressurized airflow rate. The
overlap distance "D" of the fan blades 21 is limited to be greater
than zero and smaller than one third of a blade average distance
"E" (0<D<1/3E), while the chord angle "A" of each of the fan
blades 21 is ranged between twenty degrees and sixty degrees
(20.degree.<A<60.degree.).
[0021] In such a manner, the overlapped fan blades 21 have an
action surface whose total action area is increased to co-operate
with the chord angle "A" of each of the fan blades 21, for
generating an airflow rate with the greatest efficiency.
[0022] Referring to FIGS. 4-6, an axial flow fan structure in
accordance with a second embodiment of the present invention
comprises a stator 30 sealingly mounted on a predetermined airflow
direction side of the rotor 20. The stator 30 includes a plurality
of stator guide vanes 31 which are sealingly arranged on a
predetermined airflow direction side of the fan blades 21.
[0023] Each of the stator guide vanes 31 includes an action surface
32 having a chord angle "a", an air inlet angle "b", and an air
outlet angle "c", wherein variations of the chord angle "a", the
air inlet angle "b", and the air outlet angle "c" of the action
surface 32 of the stator guide vane 31 further increase the
pressurization of the pressurized airflow rate, thereby guiding the
airflow rate with a high flow rate sent from the rotor 20. In such
a manner, the airflow rate having a high flow rate and high
pressurization can be guided more efficiently to a predetermined
direction. In addition, the stator guide vane 31 has a
configuration that can be adjusted according to the requirements of
the generated airflow rate of the rotor 20.
[0024] In practice, referring to FIGS. 2-6, the rotor 20 is
provided with a plurality of fan blades 21 that are arranged in a
head-tail overlap arrangement manner with each other. By means of
the head-tail overlap arrangement of the fan blades 21, the
periphery of the rotor 20 may be provided with more fan blades 21,
and more action surfaces 22 of the fan blades 21. Therefore, the
action surface 22 of the fan blade 21 has a larger total action
area, so that the action surface 22 of the fan blade 21 can provide
the front space 23 with a sufficient pressurization, while
variations of the chord angle "A", the air inlet angle "B", and the
air outlet angle "C" of the fan blade 21 together with the overlap
distance "D" of the fan blades 21 will reduce pressure loss of the
airflow of the front space 23. Accordingly, the airflow rate sent
by the rotor 20 of the present invention is greater than that sent
by the conventional fan. Therefore, the axial flow fan structure in
accordance with the present invention has the optimal airflow rate
with an increase of pressure head.
[0025] Subsequently, in accordance with the present invention, a
stator 30 is sealingly mounted on a predetermined airflow direction
side of the rotor 20, and the stator 30 includes a plurality of
stator guide vanes 31 which are sealingly arranged on a
predetermined airflow direction side of the fan blades 21.
[0026] Although the airflow sent by the rotor 20 of the present
invention still produces a non-directional flow momentum, all of
the flow momentum still has to be drained outward through the
stator guide vanes 31 of the stator 30, so that the non-directional
airflow with flow momentum of the tangent direction and the normal
direction will enter the spans of the stator guide vanes 31 of the
stator 30. By means of pressure of the pressurization of the action
surface 32 of the stator guide vane 31, the airflow sent by the
rotor 20 will be pressurized again through the pressure recovery
from tangential flow momentum, and the action surface 32 of the
stator guide vane 31 will have the airflow having a high flow rate
and high pressurization be guided to a predetermined direction more
efficiently, thereby preventing generating excessive
non-directional flow momentum, and thereby further reducing loss of
the pressure head.
[0027] Referring to FIG. 7, in general, a high flow rate region 33
produced by a common axial flow fan is not directly suitable in a
flow conduit of a more closed cooling system, and will be affected
by the non-directional airflow (loss of airflow pressure), while a
common working range is usually located in the low and middle flow
rate region 34. Therefore, the present invention is especially used
to inspect and test the increase of airflow pressure of the low and
middle flow rate region 34. FIG. 7 is a graph showing the
experimental results of the rotor 20 and stator 30 of the present
invention in conjunction with the conventional axial flow fan 10.
Type I is a performance curve tested from the conventional axial
flow fan structure 10. Type II is a performance curve tested from
the conventional axial flow fan structure 10 in conjunction with
the stator 30 of the present invention. Type III is an airflow rate
performance curve tested from the axial flow fan structure of the
present invention, wherein the rotor 20 co-operates with the stator
30 to achieve the function of the present invention. It can be seen
from Type III that, the rotor 20 co-operating with the stator 30 of
the present invention has the optimal airflow rate and pressure
head.
[0028] It should be clear to those skilled in the art that further
embodiments may be made without departing from the scope of the
present invention.
* * * * *