Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02507350 2008-08-18
1
TITLE OF THE INVENTION
Air filtration assembly
FIELD OF THE INVENTION
[001] The present invention relates to air filtration. More specifically, the
present invention is concerned with an air filtration assembly.
BACKGROUND OF THE INVENTION
[002] In a commonly used type of air filtration assembly, a removable filter
is
inserted within an air duct. A flange extends substantially radially
inwardly within the air duct and the filter abuts the flange. Such
equipment is typically used in many types of industries, including in
restaurants and in the pharmaceutical industry, among others.
[003] If the filter is a high efficiency filter, there is a need to have a
relatively
good seal between the filter and the flange. Indeed, having a high
efficiency filter while allowing some contaminated air to pass around the
filter results in air that is still contaminated, which defeats the objective
typically pursued through the use of a high efficiency filter.
[004] In a first prior art method, the filter extends substantially across the
whole cross-section of the air duct and is simply pushed by air pressure
onto the flange. However, this method is relatively complex to
implement properly if air leaks between the filter and the flange are to be
minimized. For example, the air pressure needs to be relatively high so
that the contact between the air filter and the flange results in the
substantially air tight seal. In addition, any imperfections in the filter or
the flange will result in leaks through which the contaminated air may
CA 02507350 2008-08-18
2
flow.
[005] In another prior art method, the filter is screwed to the flange through
the
use of screws that engage both the filter and the flange. While it is
relatively easy to obtain a good seal using this method, there are some
drawbacks, especially in the restaurant industry.
[006] Indeed, the screws and the filter are typically located upstream from
the
flange and are therefore exposed to the contaminated air. If the
contaminated air contains grease or oils, for example, the screws and
the filter will become soiled during use of the air filtration assembly.
When time comes to change the filter, technicians then typically have to
manipulate dirty components. Therefore, it is common for people
installing such filters to only fasten some of the screws, namely those
that will results in relatively low exposure to dirty components upon
removal of the filter. The installation of only some of the screws may
result in air leaks between the filter and the flange.
[007] Against this background, there exists a need in the industry to provide
a
novel air filtration assembly.
OBJECTS OF THE INVENTION
[008] An object of the present invention is therefore to provide an improved
air
filtration assembly.
SUMMARY OF THE INVENTION
[009] In a first broad aspect, the invention provides an air filtration
assembly.
The air filtration assembly includes a filter. An air duct defines an inlet,
an outlet and passageway extending therebetween. The air duct further
CA 02507350 2008-08-18
3
defines a filter-receiving portion for receiving the filter between the inlet
and the outlet. The filter-receiving portion includes a filter-retaining
surface extending substantially radially inwardly into the passageway.
The filter-receiving portion includes a filter-securing assembly for
securing the filter against the filter-retaining surface. The filter-securing
assembly is selectively operable between a non-retaining configuration
and a retaining configuration. In the non-retaining configuration, the filter
is removable from the filter-receiving portion. In the retaining
configuration, the filter is secured against the filter-retaining surface
through the filter-securing assembly engaging at least in part the filter so
as to bias the filter towards the filter-retaining surface.
[0010] In some embodiments of the invention, the filter-securing assembly
includes a filter-securing member having an eccentric cylinder.
[0011] Advantageously, the filter-securing assembly is relatively easy to use
and is positionable so that exposure of an intended user to dirty parts of
the air filtration assembly during installation and removal of the filter is
relatively small.
[0012] In addition, the filter-securing assembly is relatively easy to use,
relatively ergonomic, and does not require specialized equipment to
achieve the retaining configuration.
[0013] In some embodiments of the invention, the filter-securing assembly is
retrofittable to existing air filtration assemblies. In these embodiments,
the filter-securing assembly is relatively easy to install.
[0014] The filter-retaining assembly is relatively easy to manufacture and, if
desired, manufacturable at relatively low costs.
CA 02507350 2008-08-18
4
[0015] In a second broad aspect, the invention provides a filter-securing
assembly retrofittable to an air filtration assembly.
[0016] Other objects, advantages and features of the present invention will
become more apparent upon reading of the following non-restrictive
description of preferred embodiments thereof, given by way of example
only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the appended drawings:
[0018] Figure 1, in a perspective view, illustrates an air filtration assembly
in
accordance with an embodiment of the present invention, the air filtration
assembly including a filter-securing assembly shown in a non-retaining
configuration;
[0019] Figure 2, in a top plan view, illustrates the air filtration assembly
of
Figure 1;
15[0020] Figure 3, in a perspective view, illustrates the filter-securing
assembly of
Figure 1;
[0021] Figure 4, in a top plan view, illustrates a filter-securing member of
the
retaining assembly of Figure 1; and
[0022] Figure 5, in a side elevation view, illustrates the operation of the
filter-
securing assembly of Figure 1 between a non-retaining configuration
and a retaining configuration.
CA 02507350 2008-08-18
DETAILED DESCRIPTION
[0023] Figures 1 and 2 illustrate an air filtration assembly 10 in accordance
with
an embodiment of the invention. The air filtration assembly 10 includes
a filter 12 and an air duct 14. As better illustrated in Figure 2, the air
5 duct 14 defines an inlet 16 and an outlet 18. A passageway 17 extends
between the inlet 16 and the outlet 18.
[0024] The air duct 14 defines a filter-receiving portion 20 for receiving the
filter
12 between the inlet 16 and the outlet 18. The filter-receiving portion 20
includes a filter-retaining surface 22 extending substantially radially
inwardly into the passageway. The filter-receiving portion 20 further
includes a filter-securing assembly 24 for securing the filter 12 against
the filter-securing surface 22. The filter-securing assembly 24 is
selectively operable between a non-retaining configuration and a
retaining configuration.
15[0025] In the non-retaining configuration, the filter 12 is removable from
the
filter-receiving portion 20. In the retaining configuration, the filter 12 is
secured against the filter-retaining surface 22 through the filter-securing
assembly 24 engaging at least in part the filter 12 so as to bias the filter
12 towards the filter-retaining surface 22. The retaining and non-
retaining configurations are better illustrated in Figure 5. In this Figure,
the filter-securing assembly is shown in the retaining configuration in full
lines and in the non-retaining configuration in phantom lines.
[0026] As seen in Figure 1, in some embodiments of the invention, the filter
12
includes a substantially rigid frame 60 within which a filtering material 62
is mounted. An abutment surface 64 of the filter frame 60 is covered
with a substantially resilient band of material 66.
CA 02507350 2008-08-18
6
[0027] The abutment surface 64 faces the filter-retaining surface 22 when the
filter 12 is received within the filter-receiving portion 20. Therefore,
biasing the abutment surface 64 towards the filter-retaining surface 22
compresses the band of resilient material 66 so as to provide a relatively
air tight seal between the filter 12 and the filter-securing surface 22.
[0028] Although not present in all embodiments of the invention, in the air
filtration assembly shown in Figure 2 access doors 26 are provided for
allowing the insertion and removal of the filter 12 into and out from the
air duct 14. In addition to the filter 12, in some embodiments of the
invention, other types of filters, such as for example tissue bag filters 28,
are provided upstream of the filter 12 or downstream (not shown in the
drawings) from the filter 12. Similar air filtration assemblies are well
known in the art and the exact configuration of filters and their location
within the air filtration assembly will therefore not be further described.
15[0029] As shown in Figure 3, the filter-securing assembly 24 includes a
filter-
securing assembly frame 30 to which a filter-securing member 32 is
secured. The filter-securing assembly frame 30 is provided within the air
duct 14.
[0030] The filter-securing member 32 includes an eccentric cylinder 34. In the
non-retaining configuration, the eccentric cylinder 34 is substantially
spaced apart from the filter 12. In the retaining configuration, the the
eccentric cylinder 34 engages at least in part the filter 12 so as to bias
the filter 12 towards the filter-retaining surface 22.
[0031] The eccentric cylinder 34 includes a cylindrical part 36. As better
seen
in Figure 4, a rod 38 defines first and second substantially opposed rod
ends 40 and 42. The rod 38 mounts the eccentric cylinder 34 within the
CA 02507350 2008-08-18
7
air duct 14. The rod 38 allows the eccentric cylinder 34 to rotate within
the air duct 14 so as to alternate between the retaining and non-retaining
configurations.
[0032] As better illustrated in Figure 4, in some embodiments of the
invention,
the filter-securing member 32 includes a handle 44 extending
substantially radially outwardly from the cylindrical part 36. For example,
the handle 44 is substantially rectilinear and substantially cylindrical.
However, in alternative embodiments of the invention, an alternative
handle extends from the eccentric cylinder 34. In yet other embodiments
of the invention, no handle is provided.
[0033] In some embodiments of the invention, the cylindrical part 36 includes
substantially longitudinal cylinder flanges 46 and 48 extending
substantially longitudinally outwardly from the eccentric cylinder 34 at
locations substantially adjacent the rod ends 40 and 42.
15[0034] In addition, in some embodiments of the invention, the eccentric
cylinder
34 is a hollow cylindrical shell to which two end plates 50 are secured at
the ends thereof. Figure 4 illustrates only one of the end plates 50. The
rod 38 is mounted through the end plates 50.
[0035] The cylinder flanges 46 and 48 engage the frame 60 when the filter-
securing member 32 is in the retaining configuration. The cylinder
flanges 46 and 48 allow having filters 12 that extend substantially
entirely across the air duct 14 while allowing to relatively easily mount
the filter-securing member 32 within the air duct 14.
CA 02507350 2008-08-18
8
[0036] Referring to Figure 3, in a specific embodiment of the invention, the
filter-securing assembly 24 includes first and second mounting brackets
58 located substantially diametrically opposed to each other within the
air duct 14. The rod ends 40 and 42 are mounted to the first and second
mounting brackets 58 and the mounting brackets 58 are secured to the
filter-securing assembly frame 30.
[0037] In some embodiments of the invention, the brackets 58 are substantially
L-shaped and each include a mounting aperture 68 (seen in Figure 4) for
receiving the rod 38 therethrough. The mounting brackets 58 are
positioned so that the mounting apertures 68 are substantially collinear
with the rod 38.
[0038] In use, the filter 12 is inserted with the air duct 14. Then, an
intended
user grasps the handle 44 and rotates the eccentric cylinder 34 about
the, rod 38 thereby causing the cylinder flanges 46 and 48 to engage
the filter frame 60. This causes the filter 12 to be biased towards the
filter-retaining surface 22, which in turn causes the resilient material 66
to be compressed and produce a substantially airtight seal. Removal of
the filter 12 from the air filtration assembly 10 is performed by reversing
these steps.
20[00391 In some embodiments of the invention, the handle 44 is positioned and
dimensioned so that when the filter-securing assembly 24 is in the
retaining configuration, the filter-securing member 32 is in equilibrium
with respect to gravity and therefore shows no tendency to rotate about
the rod 38. In other words, the center of mass of the filter-securing
member 32 in the retaining configuration is substantially vertically
aligned with the longitudinal axis of the rod 38. Since the filter-securing
member 32 is in equilibrium, vibrations present in the air filtration
CA 02507350 2008-08-18
9
assembly 10 are unlikely to cause the filter-securing member 32 to move
towards the non-retaining configuration.
[0040] In some embodiments of the invention, the filter-securing assembly 24
is
manufactured with the rest of the air filtration assembly 10. In other
embodiments of the invention, the filter-securing assembly 24 is
retrofittable to an already existing air filtration assembly. In these cases,
it is only required that mounting brackets 58 be suitably positioned within
an existing air duct 14 and that the filter-securing member 32 be
mounted to the brackets 58.
10[00411 In some embodiments of the invention, the filter-securing assembly 24
is
manufactured using steel, such as for example stainless steel.
However, it is within the scope of the invention to use any suitable
material in manufacturing the filter-securing assembly.
[0042] Although the present invention has been described hereinabove by way
of preferred embodiments thereof, it can be modified, without departing
from the spirit and nature of the subject invention as defined in the
appended claims.
