U.S. patent application number 09/996994 was filed with the patent office on 2003-04-24 for multi-blade centrifugal fan.
Invention is credited to Kim, Jae-Won.
Application Number | 20030077174 09/996994 |
Document ID | / |
Family ID | 19715185 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030077174 |
Kind Code |
A1 |
Kim, Jae-Won |
April 24, 2003 |
Multi-blade centrifugal fan
Abstract
A multi-blade centrifugal fan, the fan arranged with a plurality
of blades in round shape and equipped with an end plate mounted
with a tip end of the plurality of blades, wherein the end plate is
centrally mounted with protruded hub toward an air intake, and here
a protruded height (Hb) of the hub is less than 0.3 times the outer
diameter (Df), such that although a hub is mounted with a driving
motor, an overall structural size is miniaturized to minimize a
flow rate loss and to prevent a remarkable fan performance
decrease.
Inventors: |
Kim, Jae-Won; (Seoul,
KR) |
Correspondence
Address: |
ANTONELLI TERRY STOUT AND KRAUS
SUITE 1800
1300 NORTH SEVENTEENTH STREET
ARLINGTON
VA
22209
|
Family ID: |
19715185 |
Appl. No.: |
09/996994 |
Filed: |
November 30, 2001 |
Current U.S.
Class: |
416/186R ;
415/188; 416/185; 416/187; 416/189 |
Current CPC
Class: |
F04D 29/283
20130101 |
Class at
Publication: |
416/186.00R ;
416/185; 416/187; 415/188; 416/189 |
International
Class: |
F04D 029/30 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2001 |
KR |
2001-63896 |
Claims
What is claimed is:
1. A multi-blade centrifugal fan, the fan arranged with a plurality
of blades in round shape and equipped with an end plate mounted
with a tip end of the plurality of blades, wherein the end plate is
centrally mounted with protruded hub toward an air intake, and here
a protruded height (Hb) of the hub is less than 0.3 times the outer
diameter (Df).
2. The fan as defined in claim 1, wherein the hub is a conical
shape having a narrow diameter at air intake.
3. The fan as defined in claim 1, wherein the hub is shaped of a
cylindrical form.
4. The fan as defined in claim 1, wherein the hub is formed at
lateral surfaces thereof with a plurality of holes for cooling the
heat of a motor disposed at a space of the hub.
Description
BACKGROUND OF THE INVENTION
[0001] 1. FIELD OF THE INVENTION
[0002] The present invention relates to a multi-blade centrifugal
fan, and more particularly to a multi-blade centrifugal fan adapted
to miniaturize a system having a fan and a driving motor and to
prevent a remarkable decrease of fan performance.
[0003] 2. DESCRIPTION OF THE PRIOR ART
[0004] Centrifugal fans, designed to induce air axially and to
discharge the air circumferencially, are generally used for
household package air conditions and the like.
[0005] This type of centrifugal fan includes a centrifugal
multi-blade fan 4 radially formed with a plurality of blades 2 and
a scroll casing 6 externally disposed at outside of the centrifugal
multi-blade fan 4 to spirally form a draft passage, as illustrated
in FIGS. 1 and 2.
[0006] The scroll casing 6 is mounted at axial direction of
centrifugal multi-blade fan 4 with an air intake 8 for inducing the
air, and the air intake 8 is formed with an air outlet 10 90
degrees relative to the air intake 8. The centrifugal multi-blade
fan 4 is equipped with an end plate 12 installed at one side end of
the plurality of blades.
[0007] The end plate 12 is centrally mounted with a hub protruding
toward the air intake and the hub is formed at a space (S) thereof
with a motor (M).
[0008] Elements that determine performance of a centrifugal fan
include cut-off interval, shape of scroll casing, shape of blade
and the like, and many studies to these elements serve to reduce
noise and increase efficiency of the centrifugal fans.
[0009] A fan mounted on a household package air conditioner is
formed with a hub protruded toward air intake at a central part of
the end plate 12 in concert with miniaturization of household
electric appliances, as illustrated in FIG. 2, and the hub is
accommodated at the space (S) thereof with the driving motor (M) to
thereby enable to reduce the overall size of the blower.
[0010] However, there is a problem in the fan thus described
according to the prior art in that the protruded hub inevitably
gives resistance to air inflow to decrease performance of the fan
while there is provided no appropriate protrusion height for the
hub for accommodating the motor as there have been no studies to
protrusion height of the hub and performance of fan, prompting to
make the fan assembly miniaturized but having to be ready to suffer
decrease of the performance.
SUMMARY OF THE INVENTION
[0011] The present invention is provided to solve the
aforementioned problems and it is an object of the present
invention to provide a multi-blade centrifugal fan adapted to
miniaturize a blower and to prevent a remarkable decrease of fan
performance.
[0012] In accordance with the object of the present invention,
there is provided a multi-blade centrifugal fan, the fan arranged
with a plurality of blades in round shape and equipped with an end
plate mounted with a tip end of the plurality of blades, wherein
the end plate is centrally mounted with protruded hub toward an air
intake, and here a protruded height (Hb) of the hub is less than
0.3 times the fan outer diameter (Df).
[0013] The hub is preferred to have a conical shape having a narrow
diameter at air intake.
[0014] The hub may be shaped of a cylindrical form.
[0015] The hub is preferred to be formed at lateral surfaces
thereof with an plurality of holes for cooling the heat of a motor
disposed at a space of the hub.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For fuller understanding of the nature and objects of the
invention, reference should be made to the following detailed
description taken in conjunction with the accompanying drawings in
which:
[0017] FIG. 1 is a schematic sectional view for illustrating a
centrifugal fan according to the prior art;
[0018] FIG. 2 is a sectional view taken along line A-A of FIG.
1;
[0019] FIG. 3 is a perspective view of a multi-blade centrifugal
fan according to a first embodiment of the present invention;
[0020] FIG. 4 is a schematic sectional view of a multi-blade
centrifugal fan according to the first embodiment of the present
invention;
[0021] FIG. 5 is a schematic sectional view of a multi-blade
centrifugal fan according to a second embodiment of the present
invention;
[0022] FIG. 6 is a graph for illustrating changed protrusion
heights of hub at the multi-blade centrifugal fan of FIG. 4 for
testing of fan performance; and
[0023] FIG. 7 is a graph for illustrating changed protrusion
heights of hub at the multi-blade centrifugal fan of FIGS. 5 for
testing of fan performance.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Now, preferred embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[0025] FIGS. 3 ad 4 illustrate the first embodiment of the present
invention.
[0026] As shown in the drawings, a multi-blade centrifugal fan 20
is circularly formed with a plurality of blades 22, each at a
predetermined interval while the plurality of blades 22 are mounted
at one lateral end thereof (motor-attached side) with an end plate
24. The plurality of blades 22 are mounted at the other lateral end
thereof (air intake side) with a support ring 26, rendering an
entire look to be of a cylindrical shape.
[0027] The end plate 24 centrally protrudes toward an air intake to
form a hub 28, where a protruded height (Hb) of the hub 28 is less
than 0.3 times the fan outer diameter (Df). Diameter at air intake
side of the hub 28 has a conical shape but rounded at corners
thereof. The hub 28 may be integrally formed with the end plate 24
or may be formed with separate member.
[0028] The hub 28 is protrusively formed at an upper central
surface thereof with a boss 30 for inserting and securing the axle
of a motor (described later) while the boss 30 is mounted at an
external surface thereof with a plurality of support ribs 32. The
hub 28 is disposed at a space (S) formed thereunder with a driving
motor (M) while a motor axle thereof is securely inserted into the
boss 30. Furthermore, the driving motor (M) is supportively fixed
at external surface or lower lateral surface thereof by scroll case
(not shown) for encompassing the multi-blade centrifugal fan
20.
[0029] The hub 28 is formed at lateral sides thereof with a
plurality of holes 34 for cooling the motor mounted at the space
(S) of the hub. The support ring 26 is a fixed frame abutted on an
external surface of the fan and maintains the plurality of blades
22 each at a predetermined interval for support.
[0030] Meanwhile, FIG. 5 illustrates a multi-blade centrifugal fan
according to the second embodiment of the present invention.
[0031] A end plate 124 according to the present embodiment is
cylindrical at a hub 128 thereof. The hub 128 is less than 0.3
times the fan diameter at protrusion height (Hb) thereof and
rounded at corners thereof. Other constructions such as blades 122,
supporting ring 126, boss 130, support rib 132, holes (not shown)
formed at sides of the hub are the same as those of the first
embodiment as shown in FIG. 4 (the first embodiment).
[0032] FIG. 6 illustrates performance result tests where, in a
multi-blade centrifugal fan having a conical shape of hub,
protrusion height (Hb) of the hub is changed from 0 times (hub not
protruded), 0.25 times, 0.33 times, 0.48 times, to 0.59 times the
fan outer diameter, such that FIG. 6 is a graph for showing a flow
rate (.phi.: non-dimension) relative to static pressure (.psi.:
non-dimension)
[0033] The condition tested is as below:
[0034] 1. Testing device: Wind tunnel having a flow rate of
1.5.about.50 m.sup.3/min, manufactured and designed in strict
accordance to ASHRAE(American Society of Heating, Refrigerating and
Air-conditioning Engineers)
[0035] 2. Testing method: Proceeded according to KSB6311
[0036] The multi-blade centrifugal fan having a conical hub used
for the test has a fan height (Hf) 0.47 times the fan outer
diameter (Df) while a maximum diameter (Db1) of the hub is 0.55
times the fan outer diameter (Df), a minimum diameter (Db2) is 0.51
times the fan outer diameter (Df) and width (Fw) of a blade is 0.09
times the fan outer diameter (Df).
[0037] As illustrated in the graph, it can be noted that
multi-blade centrifugal fans, each having a protrusion height (Hb)
of hub 0.25 times and 0.33 times the fan outer diameter (Df)
respectively, almost approach a graph of a multi-blade centrifugal
fan (Hb=0) of a hub not protruded.
[0038] The following table is a numerated graph of FIG. 6, where
comparisions are given between flow rate (maximum flow rate) of a
multi-blade having a zero protrusion height (Hb) of hub and flow
rate decrease rate of protruded hub.
1 Protrusion height of hub 0.25Df 0.33Df 0.48Df 0.59Df Flow rate
decrease rate 2% 4% 8% 12% (against maximum flow rate)
[0039] FIG. 7 illustrates performance test results where, in a
multi-blade centrifugal fan having a cylindrical shape of hub,
protrusion height (Hb) of the hub is changed from 0 times
(hub-not-protruded state), 0.30 times, 0.41 times, 0.55 times and
0.66 times the fan outer diameter (Df), such that FIG. 7 is a graph
for illustrating a flow rate (.phi.: no dimension) versus static
pressure (.psi.: no dimension).
[0040] The testing device and method are the same as those of the
multi-blade centrifugal fan having a conical shape of hub, where
the multi-blade centrifugal fan mounted with a cylindrical shape of
hub used for the test has a fan height (Hf) 0.47 times the fan
outer diameter (Df) while diameter (Db) of the hub is 0.51 times
the fan outer diameter (Df) and width (Fw) of a blade is 0.09 times
the fan outer diameter (Df).
[0041] As illustrated in the graph, it can be noted that a
multi-blade centrifugal fan disposed with a hub protrusion height
(Hb) 0.30 times the fan outer diameter (Df) nearly approaches a
graph of a multi-blade centrifugal fan having a hub of no
protrusion (Hb=0).
[0042] The flowing table is a numerated graph of FIG. 7 where a
flow rate decrease rate of protruded hub is given against flow rate
(maximum flow rate) of a multi-blade centrifugal fan having a zero
hub protrusion height.
2 Protrusion height of hub 0.30Df 0.41Df 0.55Df 0.66Df Flow rate
decrease rate 5% 15% 20% 22% (against maximum flow rate)
[0043] As shown in the graphs and tables, although a protruded hub
decreases performance, abrupt performance decrease has almost
nothing to do with hub shape, and it can noted that the abrupt
performance decrease occurs where protrusion height (Hb) exceeds
approximately 0.40 times the fan outer diameter (Df), and it is
preferable to have a hub protrusion height (Hb) less than
approximately 0.30 times the fan outer diameter (Df).
[0044] As apparent from the foregoing, there is an advantage in the
multi-blade centrifugal fan thus described according to the present
invention in that although a hub is mounted with a driving motor,
an overall structural size is miniaturized to minimize a flow rate
loss and to prevent a remarkable fan performance decrease.
* * * * *