Fluid reaction surfaces (i.e. – impellers) – Specific blade structure – Cantilever blade
Reexamination Certificate
2000-07-31
2002-05-28
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Specific blade structure
Cantilever blade
C416S22300B, C416SDIG002
Reexamination Certificate
active
06394754
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to an axial flow fan for refrigerators, used for cooling the machines set within the machine compartment of a refrigerator, and, more particularly, to an axial flow fan for refrigerators, designed to have three blades, a diameter ratio of 0.21 to 0.25, a large sweep angle, a large pitch angle and a high camber ratio, thus forming a smooth air circulation within the machine compartment and more effectively cooling the machines within the machine compartment.
2. Description of the Prior Art
FIG. 1
is a perspective view showing the construction of a conventional side-by-side type refrigerator.
FIG. 2
is a perspective view, showing the interior construction of the conventional side-by-side type refrigerator, and a cool air current within the refrigerator.
FIG. 3
is a left-side view of FIG.
2
.
FIG. 4
is a right-side view of FIG.
2
.
FIG. 5
is a plan view, showing the interior construction of the machine compartment of a conventional refrigerator and a cool air current within the compartment.
FIG. 6
is a front view of FIG.
2
.
As shown in
FIGS. 1
to
4
, the cabinet of a conventional side-by-side type refrigerator is vertically partitioned into two vertical sections in its interior, thus defining a freezer compartment
10
within one of the two vertical sections and a fresh compartment
20
within the other vertical section.
In the above refrigerator, an evaporator
11
is installed in the rear portion of the freezer compartment
10
and generates cool air through a heat exchanging process. A cool air supply fan
13
is installed above the evaporator
11
and provides suction for drawing the cool air from the evaporator
11
and supplying the cool air into both the freezer compartment
10
, and the fresh compartment
20
.
In the lower section of the cabinet of the above refrigerator at a position under the two compartments
10
and
20
, is an equipment compartment
21
, in which a variety of equipment, such as a compressor
22
, a condenser
23
and an axial flow fan
25
, are located. As well known to those skilled in the art, the compressor
22
is used for compressing refrigerant for the refrigeration cycle, the condenser
23
condenses the compressed refrigerant from the compressor
22
through a heat exchanging process, and the axial flow fan
25
is used for cooling both the compressor
22
and the condenser
23
using an air current.
The above axial flow fan
25
is firmly mounted to the rotating shaft of a drive motor
26
, and is rotated in conjunction with the motor
26
. A shroud
27
is installed around the blades of the axial flow fan
25
to protect the blades.
In an operation of such a conventional side-by-side type refrigerator, refrigerant is compressed by the compressor
22
to become high temperature and high pressure gas refrigerant, and flows into the condenser
23
. In the condenser
23
, the gas refrigerant dissipates heat into the surrounding air and becomes liquid refrigerant acquiring the room temperature, and a high pressure.
The liquid refrigerant is, thereafter, output from the condenser
23
to pass through a capillary tube while being reduced in pressure, thus partially becoming two-phased refrigerant including a liquid phase and a gas phase. The refrigerant flows from the capillary tube into the evaporator
11
within the freezer compartment
10
and is completely vaporized within the evaporator
11
to become low pressure gas refrigerant while receiving heat from air surrounding the evaporator
11
, thus cooling the air.
The cool air, formed through a heat exchanging process of the evaporator
11
, is supplied into both the freezer compartment
10
and the fresh compartment
20
. The above-mentioned refrigeration cycle is repeated to keep the two compartments
10
and
20
at desired low temperatures.
During such an operation of the refrigerator, the axial flow fan
25
installed in the machine compartment
21
cools both the compressor
22
and the condenser
23
using an air current.
The air current from the axial flow fan
25
flows within the machine compartment
21
as follows: Outside air, or atmospheric air is primarily introduced into the machine compartment
21
through an air inlet port
21
due to the suction force provided by the axial flow fan
25
.
Within the machine compartment
21
, the inlet air passes through the drive motor
26
by the suction force of the fan
25
, and passes through both the fan
25
and the shroud
27
so as to reach the condenser
23
.
The air passes, through the condenser
23
while absorbing heat dissipated from the refrigerant flowing within the condenser
23
. Thus, the air cools the condenser
23
.
After passing through the condenser
23
, the air passes through the compressor
22
, cooling the surface of the compressor's housing, prior to being discharged from the machine compartment
21
into the atmosphere through an air outlet port
21
.
In a brief description, inlet air, sucked into the machine compartment
21
by the suction force of the axial flow fan
25
, primarily cools the condenser
23
, thus improving heat exchange efficiency of the condenser
23
and finally improving refrigeration efficiency of the refrigerator. The inlet air within the machine compartment
21
secondarily cools the external surface of the compressor
22
, thus keeping the compressor
22
at a desired low temperature, and preventing deterioration of the operational performance of the compressor.
Therefore, the operational performance of the axial flow fan is one of the important factors determining the refrigeration efficiency, and the operational noise of the refrigerator.
Such a conventional axial flow fan
25
for refrigerators typically has three blades, an outer diameter of the fan
25
ranging from 145 mm to 165 mm, a small blade sweep angle, a small blade pitch angle, and a low blade camber ratio, causing a refrigerator to have low refrigeration efficiency, and to generate noise substantial enough to disturb individuals near the refrigerator.
A small blade sweep angle increases the undesirable operational noise of the fan
25
. A small blade pitch results in a reduction in the width of the blades, therefore an axial flow fan such as fan
25
is not suitable to draw a desirable quantity of air. When the blade camber ratio (%) is as low as described above, it is almost impossible to effectively increase the static pressure of fluid passing through both the axial flow fan and the shroud. In order to overcome such a problem, the fan
25
has to be rotated at an exceedingly high rpm.
Therefore, it is necessary to optimally design a variety of blade designing factors, such as the number of blades, diameter ratio, sweep angle, pitch angle and camber ratio so as to allow the designing factors to agree with desired operational conditions of a refrigerator. When such designing factors of the axial flow fan are optimally designed as described above, it is possible to optimally operate the axial flow fan through an inverter control process while supplying a adequate quantity of air to both the compressor and the condenser and achieving an adequate rpm of the fan, and effectively reducing operational noise of the fan.
SUMMARY OF THE INVENTION
Accordingly, the present axial flow fan was invented having in mind the above problems occurring in the prior art, and an object of the present invention is to provide an axial flow fan for refrigerators, which is designed to allow air to actively circulate within the machine compartment of a refrigerator, thus accomplishing smooth inflow and outflow of air, and eliminating operational noise caused by disturbed air circulation within the machine compartment and increasing the quantity of inflow and outflow air, and delivering an adequate quantity of air to both the compressor and the condenser, and effectively reducing operational noise of the refrigerator.
In order to accomplish the above object, the preferred embodiment of the present invention provides an axial flow fan
Birch & Stewart Kolasch & Birch, LLP
LG Electronics Co., Ltd.
Look Edward K.
McAleenan James M
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