Rotary kinetic fluid motors or pumps – Axially opposed working fluid paths to or from runner – Pump impeller means
Reexamination Certificate
2001-09-17
2003-04-01
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Axially opposed working fluid paths to or from runner
Pump impeller means
C415S102000, C415S119000, C416S23100A, C416S185000, C416S184000
Reexamination Certificate
active
06540476
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a centrifugal fan, and more particularly to a centrifugal fan improved to reduce the noise.
2. Description of the Prior Art
Generally, the conventional centrifugal fan as shown in FIG.
1
(
a
) is composed of a frame
10
, a motor
20
and an impeller
30
. Among these, the frame
10
includes a intake
11
and an outlet(not shown). The motor
20
mounted to the frame
10
is used to rotate the impeller
30
. The impeller
30
further includes a hub
31
, a bottom plate
32
and a plurality of blades
33
formed thereon.
Still referring to FIG.
1
(
a
), the blades
33
urge the inlet air from the a flow path parallel to the axis of the impeller
30
, outward radially away from the hub
31
. However, such the conventional centrifugal fan suffers the problem that the noise caused by the uneven inlet airflow passing through the intake
11
and the impeller
13
.
Another conventional centrifugal fan as shown in FIG.
1
(
b
) is composed of a frame
10
, a motor
20
and an impeller
30
. Among these, the frame
10
includes two inlets including a first intake
11
and a second intake
12
, and an outlet (not shown). A plurality of ribs
13
are formed in the second intake
12
. The motor
20
mounted to the frame
10
is used to rotate the impeller
30
. The impeller
30
further includes a hub
31
, a bottom plate
32
and a plurality of blades
33
formed thereon.
However, the drawbacks of the conventional centrifugal fan are as follows. First, the inlet airflow through the first intake
11
and that through the second intake
12
interferes with each other and the disturbance as well as the noise thus occur. Furthermore, the noise occurs during the blades
33
cross the rib
13
.
Therefore, there is a need in the art for solving the above-mentioned problems.
SUMMARY OF THE INVENTION
The object of the present invention is to reduce the noise of a centrifugal fan. The object of the present invention is achieved by (1) isolating the inlet airflow through the first intake and the inlet airflow through the second intake so as to eliminate the disturbance; (2) enlarging the interval between the first intake and the impeller so as to smooth the inlet airflow; and (3) providing the structure that the second blade and the rib form an intersection angle of about 90 degree as the second blade crosses the rib.
The centrifugal fan of the present invention comprises a frame, a rotatory means and an impeller. Among these, the frame has a first intake, a second intake, at least one air outlet (not shown) and a plurality of ribs. The rib crosses the second intake. The rotatory means such as a motor, mounted in the frame is used to rotate the impeller.
The impeller further includes a hub, a partition, a plurality of first blades and a plurality of second blades. Among these, the hub is coupled to the rotatory means such that the impeller can be rotated by means of the rotatory means. The partition extends outward along the radial direction of the hub so as to isolate the inlet air of the first intake and that of the second intake and thus reduce noise.
Additionally, the partition further has a first surface and a second surface opposite to each other. A plurality of first blades are formed on the first surface. The first blades are separated form the hub. That is, the first blades do not directly connect with the hub. Similarly, a plurality of second blades are formed on the second surface. The second blades are separated form the hub. That is, the second blades do not directly connect with the hub. The second blade and the rib form an intersection angle of about 90 degrees as the second blade crosses the rib. Therefore, the noise is reduced.
It should be noted that each of the first blades or the second blades selectively includes a cut corner formed thereon. In the first blades, the cut corner is adjacent to the edge of the first intake. In the second blades, the cut corner is adjacent to the edge of the second intake. In this manner, the interval between the first intake and the impeller is enlarged so as to reduce noise. Further, the first blades may be arranged asymmetrically or symmetrically with respect to the second blades.
REFERENCES:
patent: 6435828 (2002-08-01), Bostwick
patent: 2027816 (1980-02-01), None
Chang Bor Haw
Huang Wen-Shi
Huang Yu-hung
Lin Kuo-Cheng
Lin Tsu Liang
Delta Electronics , Inc.
Intellectual Property Solutions Incorporated
Look Edward K.
White Dwayne J.
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