Fluid reaction surfaces (i.e. – impellers) – Rotor having flow confining or deflecting web – shroud or... – Radially extending web or end plate
Reexamination Certificate
1997-08-06
2001-04-17
Verdier, Christopher (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Rotor having flow confining or deflecting web, shroud or...
Radially extending web or end plate
C416S188000, C416S22300B, C416S242000, C416SDIG005
Reexamination Certificate
active
06217285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an impeller for use in a centrifugal blower employed by air conditioning equipment and the like, the impeller comprising a hub for receiving a driving torque at a central portion thereof, a shroud of a ring-like shape in plane formed with an opening for air intake at the center thereof and opposed to the hub across a required distance therebetween, and a plurality of vane members interposed between the hub and shroud as circumferentially spaced from one another at required intervals, and more particularly to an impeller adapted to take in air from the air intake
12
a
of the shroud and to efficiently discharge the air from the impeller.
1. Description of the Related Art
Conventionally, the air conditioners have employed various types of blowers for feeding air to the heat exchangers and the like. A centrifugal blower has been widely used as one of such blowers.
The centrifugal blowers have generally employed an impeller
10
comprising a hub
11
of a circular shape in plan having a protrusion at the center thereof, a shroud
12
of a ring-like shape in plane formed with an opening for air intake
12
a
and opposed to the hub
11
across a required distance therebetween, and a plurality of vane members
13
interposed between the hub
11
and shroud
12
as circumferentially spaced from one another at required intervals, as shown in
FIGS. 1 and 2
.
The centrifugal blower is arranged such that a torque is applied to the central portion of the hub
11
for rotating the impeller
10
which, in turn, is allowed to produce an air flow entering the impeller
10
from the air intake
12
a
of the shroud
12
to be guided by the rotating vane members
13
through gaps between the hub
11
and shroud
12
and out of the outer periphery of the impeller
10
.
Various types of vane members
13
have heretofore been developed in many attempts to increase the efficiency of discharging the air from the aforementioned impeller
10
which is adapted to rotate for producing the air flow running thereinto from the air intake
12
a
to be guided by the rotating vane members
13
through the gaps between the hub
11
and shroud
12
and out of the outer periphery of the impeller
10
.
In the conventional impeller as shown in
FIG. 3
, the vane members
13
are interposed between the hub
11
and the shroud
12
in a manner such that leading edges of the vane members
13
each form an angle &thgr; (inlet angle) with a tangent line to an inner circumference defined by the vane members
13
, the angle
0
conforming to an inflow angle &phgr; of the air flow introduced into the gap between adjacent vane members
13
. Each vane member
13
has the inlet angle &thgr; at any points of a span between the hub
11
and shroud
12
.
Unfortunately, if the impeller
10
with the vane members
13
of such an arrangement is caused to rotate to produce the air flow running into the impeller
10
and through the gaps between the hub
11
and shroud
12
to be discharged from the outer periphery of the impeller
10
, the air flow guided by the vane members
13
fails to run in line with the surfaces thereof, thus departing therefrom and hence, the occurrence of eddies results. The eddies interferes with the flow of air to be discharged as guided by the vane members
13
and hence, the efficiency of air discharge is decreased and increased noises are produced during operation.
Furthermore, the conventional impeller
10
is arranged such that the air is drawn through the air intake
12
a
and guided through the gaps between the hub
11
and shroud
12
to be discharged horizontally from the outer periphery of the impeller
10
. Accordingly, the vane members
13
each have an trailing edge portion substantially extended horizontally, as seen in
FIGS. 4 and 5
.
Unfortunately, in the arrangement adapted for the air flow running into the impeller
10
from the air intake
12
a
to be discharged horizontally from the outer periphery thereof as guided by the vane members, air streams closer to the shroud
12
with the air intake
12
a
are reduced in a flow rate as discharged whereas air streams closer to the hub
11
are correspondingly increased in the flow rate as discharged. A difference of the flow rate between the air streams near the shroud
12
and those near the hub
11
results in the occurrence of eddy which, in turn, causes turbulence of the air flow. The turbulent air flow not only leads to an increased noise during operation but also interferes with the flow of air to be discharged as guided by the vane members
13
. As a result, the air feeding efficiency is decreased.
SUMMARY OF THE INVENTION
It is therefore, an object of the invention to provide the impeller for use in the centrifugal blower, which is caused to rotate for producing an air flow running thereinto from the air intake at the center of the shroud and guided by the vane members through the gaps between the hub and shroud and out of the outer periphery of the impeller, the impeller contributing to the reduction of occurrence of eddy or the like produced from the air flow departed from the vane members and to a smooth air flow running in line with the vane members for an efficient discharge of the air from the outer periphery of the impeller.
It is another object of the invention to reduce noises while the impeller is caused to rotate in the aforesaid manner for discharging the air from the outer periphery thereof.
According to a first aspect of the invention, the impeller for use in the centrifugal blower comprises a hub for receiving a driving torque at a central portion thereof, a shroud of a ring-like shape in plane formed with an opening for air intake and opposed to the hub across a required distance therebetween, and a plurality of vane members interposed between the hub and shroud as spaced from one another at required intervals, the impeller having an arrangement wherein an leading edge of each vane member forms varied angles (inlet angles) with a tangent line thereat such as to conform to inflow angles of an air flow at different points of a span between the shroud and hub.
According to the impeller of the first aspect of the invention wherein the leading edge of each vane member has varied angles such as to conform to the inflow angles of the air streams at different points of the span between the shroud and hub, the vane members can cause the air streams to run in line with the surfaces thereof at any points of the span between the hub and shroud, while the impeller is rotated to produce the air streams drawn thereinto and guided by the vane members through the gaps between the hub and shroud and out of the outer periphery of the impeller. Such air streams are effective to reduce the occurrence of eddy or the like, thus allowing the vane members to more efficiently discharge the air from the outer periphery of the impeller. Additionally, the production of noises is also decreased.
According to a second aspect of the invention, the impeller for use in the centrifugal blower comprises a hub for receiving the driving torque at a central portion thereof, a shroud of a ring-like shape in plane formed with an opening for air intake at the center thereof and opposed to the hub across a required distance therebetween, and a plurality of vane members interposed between the hub and shroud as circumferentially spaced from one another at required intervals, the impeller having a arrangement wherein a trailing edge of each vane member forms varied angles (outlet angles) with the tangent line thereat such as to conform to outflow angles of the air discharged by the vane members at different points of the span between the shroud and hub.
According to the impeller of the second aspect of the invention wherein the trailing edge of each vane member forms varied outlet angles such as to conform to the outflow angles of the discharged air at different points of the span between the shroud and hub, the vane members can cause the air streams to run in line with the su
Kurokawa Michihiro
Nabeshima Noriyuki
Nasako Kenji
Oki Katuyoshi
Ueyama Kenji
Armstrong, Westerman Hattori, McLeland & Naughton
Sanyo Electric Co,. Ltd.
Verdier Christopher
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