Rotary kinetic fluid motors or pumps – Working fluid passage or distributing means associated with... – Vane or deflector
Reexamination Certificate
1999-08-17
2001-06-12
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Working fluid passage or distributing means associated with...
Vane or deflector
C415S209100, C415S193000, C415S199400, C415S223000, C416S24700A
Reexamination Certificate
active
06244818
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to a fan guard structure, and more particular to an improved fan guard structure which imparts a supercharging function to a fan for efficient heat dissipation.
BACKGROUND OF THE INVENTION
Currently, heat-dissipating fans commonly used in personal computers include an axial-flow fan, a centrifugal fan and a cross-flow fan. Of these, the most popular one is supposed to be an axial-flow fan.
A fan is primarily consisted of a rotor device and a fan guard arranged beside the rotor device for supporting the rotor device. Referring to
FIG. 1
, the fan guard
10
of a conventional axial-flow fan is constructed by a main frame
101
, a motor holder
102
and a plurality of ribs
103
arranged between the main frame
101
and the motor holder
102
. The rotor device
11
includes a motor (not shown) received in the motor holder
102
, a shaft ring
111
connected to and driven by the motor to revolve, and a plurality of rotor blades
112
fixed on the circumferential surface of the shaft ring
111
and revolving with the shaft ring
111
to work on the surrounding air to generate an airflow. Through the work of the rotor blades on the surrounding air, the blast pressure is changed from a relatively low value on the air inlet side into a relatively high value on the air outlet side. That is, there is a blast pressure enhancement on the air outlet side.
Unfortunately, when the airflow further flows through the fan guard having the structure as shown in FIG.
1
and as described above, turbulent flows will be generated after the airflow encounters the ribs so as to have an adverse effect on the blast pressure enhancement. Consequently, the efficiency of the fan is reduced.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an improved fan guard structure which has a function of supercharging a fan in addition to supporting a rotor device.
The present invention is related to a fan guard to be mounted beside a rotor device of a fan for supporting the rotor device. Additionally, the fan guard according to the present invention interacts with an airflow generated by the revolution of the rotor blades to supercharge the fan.
The fan guard essentially includes a main frame, and a set of guard blades radially arranged inside the main frame and fixed onto an inner surface of the main frame by each one end thereof. Generally but not definitely, a count of the guard blades is about 1-2 times of that of the rotor blades. Preferably, the other ends of the guard blades are fixed onto a cylindrical motor holder which is located at the center of the main frame, and is hollow for receiving therein a motor used for driving the rotor blades to revolve. Especially preferred, at least one reinforcing ring connecting all of the guard blades is provided for strengthening the far guard. In general, the guard blades are made of plastic. Nevertheless, the guard blades can also be made of a material other than plastic for a desired purpose. For example, they can be made of a metal which is advantageous for heat dissipation.
To assemble the fan, the main frame of the fan guard is coupled to the frame of the rotor device. Alternatively, the main frame of the fan guard is integrally formed with the frame of the rotor device so that the fan can be assembled by installing the non-integrally formed parts into the common frame. The fan guard can be arranged either upstream or downstream of the rotor device. Preferably, the fan guard includes two sets of frame and guard blades respectively arranged by both sides of the rotor device. By properly designing the shapes and the position arrangement of the guard blades relative to the rotor blades, the upstream guard blades can guide air into the rotor device at an angle to make an air inflow to the rotor device have an additional tangential velocity which increases the work of the rotor blades on air, and on the other hand, the downstream guard blades can transform a tangential velocity of an air outflow from the rotor device into a static pressure, both advantageous for supercharging the fan. For example, all of the guard blades are made to have a shape identical to the shape of the rotor blades. As for the position arrangement of the downstream guard blades relative to the upstream rotor blades, one of the guard blades and one of the rotor blades constitute a near letter C configuration in a cross-sectional view instantaneously. Contrarily, the position arrangement of the upstream guard blades relative to the downstream rotor blades makes one of the guard blades and one of the rotor blades constitute a near letter S configuration in a cross-sectional view instantaneously.
Furthermore, by taking the combination of a fan guard according to the present invention and a rotor device as a fan unit, a fan can be designed to include a plurality of such fan units to enhance efficiency.
REFERENCES:
patent: 2154313 (1939-04-01), McMahan
patent: 3342254 (1967-09-01), Fujie
patent: 3883264 (1975-05-01), Rao
patent: 4724747 (1988-02-01), Sturm et al.
patent: 4968216 (1990-11-01), Anderson et al.
patent: 5839205 (1998-11-01), Hung
patent: 6024536 (2000-02-01), Tsubakida et al.
patent: 57-186098 (1982-11-01), None
patent: 226799 (1990-02-01), None
patent: 10205497 (1998-08-01), None
Delta Electronics , Inc.
Greer Burns & Crain Ltd
Look Edward K.
Woo Richard
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