Note: Descriptions are shown in the official language in which they were submitted.
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Ti 1e: AIR CLEANER WITH WASHABLE FILTER
FIELD OF THE INVENTION
This invention relates generally to air cleaners, for example,
vacuum cleaners.
BACKGROUND OF THE INVENTION
The invention has been devised primarily, though not
exclusively, in the context of vacuum cleaners that include at least one
cyclone separator for cleaning air that flows through the vacuum cleaner,
and a secondary filter downstream from the cyclone separator, for removing
small particulate matter.
Cyclone separators, which are sometimes referred to merely
as cyclones, are devices that use centrifugal force and low pressure caused
by spinning motion, to separate materials of differing density, size and
shape. Cyclone separators are disclosed, for example, in United States
Patents Nos. 3,425,192 and 4,593,429.
PCT Publication No. WO 00/40135 published July 13, 2000
discloses a vacuum cleaner that includes a cyclone separator in
combination with a downstream electrostatic precipitator for removing fine
particulate matter from the air that passes through the cyclone separator.
As disclosed in this publication, the cyclone separator is removable from the
vacuum cleaner as a unit and the unit includes a bin for collecting dirt that
has been removed by the cyclone. The bin can be separated from the
remainder of the cyclone and emptied.
Cleaning of the electrostatic precipitator is a separate
challenge. In general, users of vacuum cleaners find it distasteful if they
are
required to come into contact with the dirt that has been removed from the
air flowing through the vacuum cleaner. Similar issues arise with other
forms of secondary filter. For example, there are currently on the market,
cyclonic vacuum cleaners that incorporate a HEPA T"" filter. Again, this type
of filter must be periodically cleaned.
SUMMARY OF THE INVENTION
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Broadly speaking, the present invention provides an air cleaner
in which air is caused to flow along an air flow path from a dirty air inlet
to a
clean air outlet, wherein the air cleaner includes a washable air filter
disposed in the air flow path. The filter is enclosed in a housing that is
removable from the air cleaner as a unit and the housing encloses the filter
so as to protect a user from contact with the filter itself. The housing has
water inlet and outlet openings arranged to allow wash water to be directed
through the filter to flush dirt from the filter without the user contacting
the
filter.
Preferably, the air cleaner includes a cyclone separator in
combination with the washable air filter and the washable air filter is
disposed downstream of the cyclone separator. More preferably, the filter is
an electrostatic filter of the type in which the filter is electrostatically
charged
by the air that flows through the vacuum cleaner. PCT Publication No.
WO 00/40135 mentioned previously discloses an electrostatic filter of this
type.
In a preferred embodiment as applied to vacuum cleaners,
both the cyclone separator and the electrostatic air filter are incorporated
in
a filter assembly that is removable as a unit from the vacuum cleaner. The
assembly may include a generally cylindrical dirt collection bin, and the
housing of the electrostatic filter may be incorporated as part of a closure
at
the top of the bin. Air leaving the cyclone when the vacuum cleaner is in use
flows upwardly through the electrostatic filter and out through an opening in
the top of the filter housing. When the closure is removed from the cyclone
bin, the outlet opening can then act as either the water inlet or outlet for
flushing the electrostatic precipitator.
BRIEF DESCRIPTION OF DRAWINGS
In order that the invention may be more clearly understood,
reference will now be made to the accompanying drawings which illustrate
a number of preferred embodiments of the invention by way of example, and
in which:
Fig. 1 is a perspective view of an upright vacuum cleaner in
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accordance with the present invention;
Fig. 2 is a perspective view of the filter assembly of the vacuum
cleaner;
Fig. 3 is a vertical sectional view through the filter housing of
the filter assembly shown in Fig. 2, after removal of the cyclone bin, and
showing flushing water flowing through the housing;
Fig. 4 is an exploded perspective view corresponding to Fig. 3
showing the electrostatic filter housing removed from the remainder of the
cyclone structure;
Fig. 5 is a perspective view showing how the filter housing can
be flushed separately from the remainder of the cyclone structure; and,
Fig. 6 is a perspective view illustrating an alternative
embodiment, in which the filter housing has flush water openings in its side
wall.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings, Fig. 1 shows an upright vacuum
cleaner in accordance with a preferred embodiment of the present invention.
The vacuum cleaner and its manner of operation are generally in
accordance with the disclosure of PCT Publication No. WO 00/40135
referred to previously, to which reference may be made for specific details
not found in the present disclosure.
The vacuum cleaner is generally denoted by reference
numeral 20 and includes a floor cleaning head 22 that is mounted on
wheels, one of which is visible at 24, for movement over a floor surface. A
dirty air inlet in the underside of the head is indicated at 26 and usually
will
accommodate a driven rotary brush or beater bar (not shown). Extending
upwardly from a rear portion of the head 22 is a support structure 28 for a
filter assembly 30 that is removable as a unit from the vacuum cleaner. The
filter assembly is shown separately in Fig. 2.
Above the filter assembly, the support structure 28 carries an
upper body portion 32 of the vacuum cleaner that incorporates a fan and
motor assembly (not shown) for drawing air through the vacuum cleaner
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and delivering cleaned air to a clean outlet 34 at the top of body portion 32.
A handle for manoeuvring the vacuum cleaner is indicated at 36.
Referring now more particularly to Fig. 2, the filter assembly 30
includes a cyclone separator generally denoted by reference 38 and an
electrostatic air filter 40 enclosed in a housing 42. A bin for collecting
dirt
removed by the cyclone separator is indicated at 44. Bin 44 has a cylindrical
side wall 46 that is transparent. Visible through the side wall of the bin is
the internal structure 48 of the cyclone separator. This includes a main inlet
pipe 50 that extends upwardly centrally of bin 44 and through which dirty air
enters the cyclone from the floor cleaning head 22 of the vacuum cleaner.
As best seen in Fig. 3, pipe 50 extends upwardly and then
laterally to a cyclone inlet opening 52 that directs air tangentially with
respect
to the internal surface of the side wall 46 of bin 44. When the vacuum
cleaner is in use, air entering bin 44 from inlet 52 spirals downwardly on the
internal surface of bin side wall 46 until it reaches a lower baffle member 54
(Fig. 2), which deflects the air inwardly and upwardly adjacent the outer
surface of inlet pipe 50. The air then enters openings 56 in an upper
housing 58 of the cyclone separator and then flows upwardly through the
electrostatic filter 40 as indicated by the ghost outline arrows 60. The air
then travels upwardly through filter 40 and leaves the filter assembly 30
through an opening 62 in the top of filter housing 42.
Referring back to Fig. 1, the flow path of air from the dirty air
inlet 26 of head 22 to the clean air outlet 34 of the vacuum cleaner is
indicated at 64. To summarize, the air travels upwardly through inlet pipe 50
of the cyclone separator to the inlet 52 of the cyclone, from where it spirals
downwardly adjacent the inner surface of the side wall 46 of the cyclone bin.
The air then travels back up adjacent the outer surface of inlet pipe 50 and
into the openings 56 of the housing 58 of the cyclone assembly. The air
then travels upwardly through filter 40, and through the upper body portion
32 of the vacuum cleaner to outlet 34.
Filter assembly 30 (Fig. 2) is removable from the remainder of
the vacuum cleaner in the manner disclosed in the PCT application referred
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to previously, by slightly depressing the filter assembly and then pulling it
outwardly. As best seen in Fig. 3, the filter assembly housing 42 has a top
surface that is angled upwardly to the right and that is shaped to provide a
handle 66 that projects forwardly of the vacuum cleaner in the assembled
condition, as best seen in Fig. 1. Thus, the user grasps the handle 66,
depresses the filter assembly slightly and pulls it forwardly and outwardly
using the handle. Fig. 2 shows the filter assembly as it would appear after
removal from the remainder of the vacuum cleaner in this fashion.
When the vacuum cleaner is in operation, dirt that is removed
from the air flowing through the vacuum cleaner by the cyclonic action of the
cyclone separator accumulates in bin 44. Referring now to Fig. 3, it will be
seen that the upper housing 58 of the cyclone assembly and the housing 42
of the filter 40 fit together to form a sub-assembly that also includes the
inlet
pipe 50 of the cyclone separator and baffle 54 (Fig. 2). The housings 42 and
58 have the same cylindrical exterior configuration and fit together so that
the sub-assembly forms a cylindrical closure that is a push-fit inside the
upper portion of cyclone bin 44. As seen in Fig. 3, the sub-assembly has
been separated from the cyclone bin 44 by lifting the sub-assembly from the
bin. Bin 44 can now be emptied of accumulated dirt. The sub-assembly
shown in Fig. 3 can be conveniently manipulated by the user holding handle
66. Filter 40 can be cleaned by directing flushing water downwardly through
opening 62 as indicated at 68; the water will flow down through filter 40 and
out through the openings 56 in the cyclone housing part 58. Thus, the user
can clean filter 40 without having to come in contact with the dirt that has
accumulated on the filter and the dirt can simply be flushed away.
It should at this stage be noted that the filter 40 is shown in the
drawings simply as a generally cylindrical filter structure that, in this
embodiment, is an electrostatic filter of the form disclosed in the PCT
application referred to previously. In principle, however, other forms of
washable filter could be used, even a mechanical particle filter.
Even though the filter 40 can be cleaned successfully as part of
the sub-assembly shown in Fig. 3, the filter housing 42 is detachable from
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the cyclone housing 58 as shown in Fig. 4, and can be flushed separately
as illustrated in Fig. 5. As can be seen in Fig. 4, a bayonet coupling
arrangement is provided filter between housing 40 and cyclone housing 58
and comprises three equi-angularly spaced bayonet fittings 70 that are
designed to allow the two housing 42 and 58 to be connected or
disconnected by relative angular rotation with respect to one another. An
actuator 72 for a detent 72a is depressed to permit such relative turning
movement. When the two housings are fitted together detent 72a engages
in a notch 73 in filter housing 42, preventing relative turning of the two
housings.
Housing 42 has a substantially open bottom wall 42a so that
the filter can be cleaned by directing water either in through opening 62 and
out through wall 42a, or in the reverse direction (after inverting housing
42).
Finally, Fig. 6 shows an alternative embodiment of the
invention. In this case, the filter housing 42 is provided with openings 74 in
its side wall through which flush water can be directed and allowed to
escape. As shown in Fig. 6, the openings 74 are in addition to the openings
that are present in the preceding embodiment, to allow for flushing of the
filter both in the direction of normal air flow through the filter (or counter
to
that direction) and in the radially inward direction. It is, however, to be
understood that, within the broad scope of the invention, it is merely
necessary that openings be provided in the housing 42 to allow flushing of
the filter and that any configuration and arrangement of openings is suitable
provided normal filtering air flow can take place through the housing.
It is to be understood that the preceding description relates to
particular preferred embodiments of the invention only and that various
additions and modifications are possible, some of which have been
indicated previously and others of which will be apparent to a person skilled
in the art. In particular, it is to be noted that the invention is applicable
to any
type of vacuum cleaner whether upright (as illustrated), canister vacuum
cleaner or central vacuum cleaner or the like. The dirty air stream which is
processed may be collected, for example, by a wand or rotating brush
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positioned in the head of the vacuum cleaner as is known in the art. The
invention may also be used with a wet/dry vacuum cleaner.
The filter assembly may include more than one cyclone
separator.
Finally, it should be noted that, while the disclosure with
reference to the drawings is directed exclusively to vacuum cleaners, the
invention may be applied to other forms of air cleaner, for example a room
air cleaner. In this latter context, an air filter assembly, for example, of
the
form shown in Fig. 2 could form part of a room air cleaner in which air is
caused to flow upwardly through the filter assembly and out into the room
through opening 62.
