Gas separation: processes – Deflecting – Centrifugal force
Reexamination Certificate
2000-01-10
2002-05-21
Hopkins, Robert A. (Department: 1724)
Gas separation: processes
Deflecting
Centrifugal force
C055S459100, C055S459200, C055S449000, C055SDIG003, C015S350000, C015S352000, C015S353000
Reexamination Certificate
active
06391095
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to cyclonic separators. In one particular application, the invention relates to a vacuum cleaner which uses the cyclonic separation of dirt from an air flow as the primary dirt separation mechanism.
BACKGROUND OF THE INVENTION
The use of a cyclone, or multiple cyclones connected in parallel or series, has long been known to be advantageous in the separation of particulate matter from a fluid stream. Typically, a relatively high speed fluid stream is introduced tangentially to a generally cylindrical or frusto-conical container, wherein the dirty air stream is accelerated around the inner periphery of the container. The centrifugal acceleration caused by the travel of the fluid in a cyclonic stream through the cyclone causes the particulate matter to be disentrained from the fluid flow and, eg., to collect at the bottom of the container. A fluid outlet is provided for the extraction of the fluid from the centre of the top of the cyclone container, as is well known in the art.
A typical flow path in a cyclone separator is as follows. Fluid to be treated is introduced tangentially at a fluid inlet located at the upper end of the cyclone container (if the cyclone container is vertically disposed). The fluid stream rotates around the inner surface of the cyclone container, and spirals generally downwardly around the inner surface. At the bottom end of the cyclone container the fluid stream travels radially inwardly, generally along the bottom of the container and then turns upwardly and proceeds vertically up and out of the cyclone container. The particulate matter separating action of the cyclonic flow occurs substantially around the inner surface. Once the air moves inwardly to the centre of the container, and upwardly there through, there is little or no dirt separation achieved.
Various types of vacuum cleaners are traditionally produced. These include built in vacuum cleaners, canister vacuum cleaners and upright vacuum cleaners. Upright vacuum cleaners have a ground engaging portion (a cleaning head) and an upwardly extending or main body portion. The ground engaging portion typically has wheels for movement of the cleaning head across a floor and a suction inlet for the intake of dirty air into the vacuum cleaner. The upwardly extending portion comprises the filter means for removing dirt which is entrained in the air. The upwardly extending portion generally has a handle for guiding the vacuum cleaner across the floor.
Traditionally in upright vacuum cleaners, the motor to draw the dirty air through the vacuum cleaner is positioned in the ground engaging head and the upward extending portion is pivotally mounted to the upper portion of the ground engaging member at a position adjacent the motor.
The advantages of cyclonic separation have been combined with an upright vacuum cleaner to provide a household cyclonic vacuum cleaner, as shown in U.S. Pat. No. 4,593,429 to Dyson. As shown in
FIG. 1
, this vacuum cleaner
10
essentially comprises a large, outer cylindrical cyclone
12
, with an inner cyclone
14
nested therein, which is mounted on a floor-cleaning head and provided with a push handle for convenient movement of the unit. A motor, located in the floor cleaning head, draws air through the cleaning head and into an intake conduit
16
, which delivers air to the dirty air inlet
18
of the outer cyclone container
12
. From the outer cyclone the air flows into inner, nested dust separating cyclone
14
, and from there, continues on through the vacuum motor, which is positioned in the ground engaging member, to a clean air exhaust port.
The air intake conduit
16
connects the floor cleaning head and the dirty air inlet in air flow communication. Air intake conduit
16
extends upwardly along the outside of outer cyclone container
12
generally parallel to the longitudinal axis of the cyclones
12
,
14
. At a position adjacent air inlet
18
to outer cyclone
12
, air intake conduit
16
bends 90° twice to travel inwardly and to provide a tangential air flow to air inlet
18
of outer cyclone container
12
.
In use, air intake conduit
16
may become blocked. If the blockage occurs at a midpoint of the conduit, it may be difficult to clear the blockage. While a clean out port may be provided, the port may not be located near where the blockage occurs. Further, the addition of a port increases the cost and complexity of the manufacture of the product.
A bend in a conduit for a fluid causes a turbulent pressure loss in the conduit as the fluid travels through the bend in the conduit and the greater the sharpness of the bend, the greater the pressure loss. The pressure loss in the air flow decreases the amount of suction which can be generated at the cleaning head of the vacuum cleaner for any given motor in the vacuum cleaner and therefore the efficiency of the vacuum cleaner.
SUMMARY OF THE INVENTION
In accordance with the instant invention, there is provided a vacuum cleaner having a source of dirty air to be treated and a housing, the cyclonic separator comprising a cyclone removably mounted in the housing and having a bottom, a fluid inlet, a wall having an inner surface and a longitudinally extending axis; and a fluid supply conduit extending along the length of the cyclone from the bottom to the fluid inlet, the fluid supply conduit conveying the dirty air substantially axially to the fluid inlet, the fluid supply conduit communicating with the source of dirty air when the cyclonic separator is in use, the fluid inlet redirecting the dirty air from an axial flow to a tangential flow and the fluid inlet is positioned within the cyclone.
In one embodiment, the fluid supply conduit extends through a central portion of the cyclone. The fluid supply conduit preferably extends coaxially with the axis of the cyclone and the fluid inlet preferably extends outwardly to the inner surface.
In another embodiment, the fluid inlet includes a curved portion without any 90° elbows.
In another embodiment, the fluid inlet comprises at least a portion that extends in a continuous curve.
In another embodiment, the fluid inlet is curved in a first direction towards the inner surface of the wall and is curved in a second direction to introduce the dirty air tangentially to the cyclone. The fluid inlet may be curved so as to sequentially redirect the air in the first direction and then the second direction. Preferably, the fluid inlet is curved so as to simultaneously redirect the air in the first direction and the second direction.
In another embodiment, the fluid inlet has a curved portion to impart a rate of change of direction in the fluid travelling there through in two axis simultaneously.
In another embodiment, the fluid supply conduit extends longitudinally through the cyclone and the cyclone is removably mounted in the housing.
In another embodiment, the downstream end of the fluid inlet extends substantially horizontally.
In another embodiment, the downstream end of the fluid inlet extends towards the bottom of the cyclone.
In another embodiment, the downstream end of the fluid inlet extends towards the bottom of the cyclone at an angle of up to 10° from a plane perpendicular to the axis.
In another embodiment, the cyclone has an outlet having a wall and a portion of the fluid inlet is nested within the outlet and a portion of the fluid inlet is positioned exterior the outlet.
In accordance with the instant invention, there is also provided a cyclonic separator having a source of fluid to be treated, the cyclonic separator comprising a cyclone having a bottom, a fluid inlet, a wall having an inner surface and a longitudinally extending axis, the fluid inlet having an upstream end and a downstream end; and, a fluid supply conduit extending substantially along the axis of the cyclone from the bottom to the upstream end of the fluid inlet, the fluid supply conduit communicating with the source of fluid when the cyclonic separator is in use, the fluid inlet is curved in a first direction towards the wall and is cur
Conrad Helmut Gerhard
Conrad Wayne Ernest
Szyluwiec Ted
G.B.D. Corp.
Hopkins Robert A.
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