Fluid reaction surfaces (i.e. – impellers) – Rotor having flow confining or deflecting web – shroud or... – Radially extending web or end plate
Reexamination Certificate
2001-08-16
2004-02-03
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Rotor having flow confining or deflecting web, shroud or...
Radially extending web or end plate
C416S22300B, C416SDIG002, C415S206000
Reexamination Certificate
active
06685433
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a turbofan, and more particularly, the present invention relates to a turbofan which is applied to a window-type air conditioner.
2. Description of the Related Art
Generally, as shown in
FIG. 1
, a window-type air conditioner has a single case
10
. In the case
10
, there are arranged a compressor
12
for compressing refrigerant, a condenser
14
for condensing the refrigerant which is compressed by the compressor
12
and thereby decreasing the temperature of the refrigerant, and an evaporator
16
for performing a heat-exchanging function using the refrigerant which is reduced in terms of its temperature by the condenser
14
.
A space which is defined in the case
10
of the window-type air conditioner is divided into an indoor part and an outdoor part by a partition panel
18
.
The evaporator
16
, a turbofan
20
for circulating room air through the evaporator
16
, and the like are disposed in the indoor part. The compressor
12
, the condenser
14
, an axial-flow fan
30
for enabling the condenser
14
to conduct a condensing function using outside air, and the like are disposed in the outdoor part.
As shown in
FIG. 2
, the turbofan
20
is composed of a hub
201
, a plurality of blades
202
which are located at a predetermined separation from the hub
201
, and a shroud
203
which is attached to distal ends of the plurality of blades
202
in opposition to the hub
201
.
The turbofan
20
is connected to a driving motor
19
in a state wherein it is disposed in a scroll case
22
which defines an air passage.
In the window-type air conditioner, warm air in a room passes through the evaporator
16
by the rotating action of the turbofan
20
and thereby is cooled. Thereafter, the cooled air is drawn into the scroll case
22
. Then, the drawn-in air is compressed by the plurality of blades
202
and discharged out of the scroll case
22
. In this way, the temperature of the air in the room is properly adjusted so as to cool the room.
At this time, the cooled air which is discharged from the scroll case
22
is not immediately re-sucked into the scroll case
22
thanks to a static pressure increase effect which is produced inside the scroll case
22
by the presence of the shroud
203
, and instead, is dispersed over a remote region.
The refrigerant, which is raised in its temperature by being brought into contact with the warm air at the evaporator
16
, is re-cooled, in the course of passing through the condenser
14
, by the outside air which flows into the outdoor portion due to rotating action of the axial-flow fan
30
, so as to be continuously circulated.
Here, air-blowing factors which determine the air-blowing characteristics of the turbofan
20
include combination factors which are created by the relationships among the respective blades
202
, individual factors which are induced by the independent nature of the respective blades
202
, and separate factors which are induced by other elements except the blades
202
.
The combinative factors include, as shown in
FIG. 3
, a number of the blades
202
, a ratio D
1
/D
2
between a diameter D
1
(that is, an inner diameter of the blades) of a circle which is obtained by connecting inner ends of the respective blades
202
and a diameter D
2
(that is, an outer diameter of the blades) of a circle which is obtained by connecting outer ends of the respective blades
202
, and a length L
2
(see
FIG. 4
a
) of a line segment (that is, a section) which connects the outer ends of two adjoining blades
202
.
The individual factors include a length L
1
of a line segment (that is, a chord) which connects the inner and outer ends of each blade
202
(see
FIG. 4
a
), an entrance angle &bgr;
1
and an exit angle &bgr;
2
of the blade
202
(see
FIG. 4
b
), a maximum camber position P and a maximum thickness t of the blade
202
(see
FIG. 4
b
), and an entrance width W
1
which is the inner length of the blade
202
and an exit width W
2
which is the outer length of the blade
202
(see FIG.
5
).
Here, the number of the blades
202
is determined depending upon the ratio between the length L
1
of the chord and the length L
2
of the section. The maximum camber position P designates the relative distance from a starting point of the blade
202
to a point of maximum thickness t when assuming that the length L
1
of the chord is 1.
The separate factors include the inner diameter Ds of the shroud
203
as shown in FIG.
5
.
In the conventional window-type air conditioner, a sirocco fan (not shown) can be used in place of the turbofan.
Because the sirocco fan has a large air-blowing rate, the size of the sirocco fan can be decreased. However, when assuming that the turbofan and the sirocco fan have the same air-blowing rate, since the sirocco fan has increased power consumption in comparison with the turbofan, the sirocco fan has the disadvantage in that its operating efficiency is degraded. As a consequence, since the turbofan has a higher operating efficiency than the sirocco fan, it is mainly used in a window-type air conditioner. On the other hand, due to the fact that the turbofan occupies an increased volume when compared to the sirocco fan having the same air-blowing rate, the turbofan adversely affects miniaturization of the air conditioner.
The conventional turbofan
20
is fabricated by a joining method or an integral forming method. In the joining method, the separately formed shroud
203
is joined to the plurality of blades
202
in a state wherein the hub
201
and the plurality of blades
202
are integrally formed with each other. In the integral forming method, by configuring the hub
201
in a manner such that the diameter of the hub
201
is less than the outer diameter D
2
of the blade
202
, the hub
201
, the plurality of blades
202
and the shroud
203
are integrally formed one with the other.
However, the joining method encounters a problem in that, since a separate procedure for joining the shroud
203
to the blades
202
is needed, the productivity of the turbofan is reduced. Also, the integral forming method suffers from defects in that significant operating noise is produced due to the structural features of the turbofan.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and thus an object of the present invention is to provide a turbofan for a window-type air conditioner, which is constructed in such a way as to be fabricated by an integral forming method, whereby the productivity of the turbofan is improved and at the same time, the air-blowing efficiency of the turbofan is improved.
In order to achieve the above object, according to one aspect of the present invention, there is provided a turbofan for a window-type air conditioner, comprising: a hub; seven to eleven blades located at a predetermined separation from the hub and gradually narrowed in their width toward the hub; and a shroud attached to the blades in opposition to the hub; wherein the entire width of the turbofan is 35-45% of an outer diameter of the blades, the exit width of the turbofan is 50-60% of the entire width, the entrance width of the turbofan is 85-92% of the entire width, the hub-side inner diameter of the blades is 45-55% of the outer diameter of the blades, and the shroud-side inner diameter of the blades is 60-70% of the outer diameter of the blades.
According to another aspect of the present invention, each blade has a shroud-side inclination angle of 30-60°, an exit angle of 50-65°, a hub-side entrance angle of 15-30°, a shroud-side entrance angle of 40-55°, a maximum camber position of 0.3-0.5, and a maximum thickness of 5-8% of the hub-side chord length or 7-12% of the shroud-side chord length.
According to still another aspect of the present invention, an inner diameter of the shroud is 70-80% of the outer diameter of the blades.
According to yet still another aspect of the present invention, the hub has a diameter which is le
Kim Sung Chun
Park Young Min
Birch & Stewart Kolasch & Birch, LLP
Look Edward K.
McAleenan J. M.
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