Note: Descriptions are shown in the official language in which they were submitted.
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AIR FILTER FOR AN EXHAUST FAN
The present invention relates to air filters and more particularly to an
air filter assembly for use with or as a cover for an exhaust fan mounted
within a
recess, for example in a ceiling.
BACKGROUND OF THE INVENTION
Ceiling mounted exhaust fans, such as those commonly installed in
bathrooms to remove moisture or odour from the air, can experience build-up of
extraneous material and accordingly become clogged with time. Such build-up
can
be detrimental to the performance of the fan, and thus it may become necessary
to
carry out either replacement of fan components or a thorough cleaning thereof,
each
of which may require some degree of disassembly. As a result, there is a
desire for
a device that can prevent or reduce build-up within a ceiling mounted exhaust
fan
assembly in order to increase the lifespan of the fan or reduce the frequency
at
which cleaning becomes necessary.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided an exhaust
fan covering system for an exhaust fan mountable within a recess, the kit
comprising:
a cover body arranged for mounting over the recess, the cover body
having an open end with a perimeter sized to surround the recess when mounted
thereover and at least one opening extending through the cover body to allow
passage of air therethrough; and
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an air filter arranged to be supported on the cover body between the at
least one opening and the open end to force airflow between the at least one
opening and the open end to pass through the air filter.
There may be provided hangers arranged to be supported on the cover
body for suspending the cover body over the recess.
The air filter may be arranged to be disposed between the hangers.
The air filter may have at least one opening extending therethrough to
allow the hangers to pass through the opening from the cover body.
The air filter may be arranged to extend about the hangers.
The air filter may be arranged to extend fully along a perimeter of the
cover body.
The air filter may comprise four inverted trapezoidal panels arranged
end to end to outline an inverted frusto-pyramidal volume.
Alternatively, the air filter may comprise four rectangular panels
arranged end to end to outline a rectangular volume.
The air filter comprises a layer of air permeable filter material and a
frame supporting the layer of air permeable filter material.
The frame may comprise two spaced apart lattices, the layer of air
permeable filter material being housed between the lattices.
There may be provided fasteners arranged to fasten the air filter to the
cover body.
The cover body may comprise clips arranged to receive the frame of
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the air filter.
The clips may be arranged to clip the frame of the air filter at an outer
perimeter of the air filter.
The filter may have a central opening therein with the clips arranged to
clip the frame of the air filter at an inner perimeter of the air filter.
The air filter may comprise fasteners supported on the frame to
engage the cover body. In this instance, the fasteners may be clips arranged
to
extend through respective ones of the openings in the cover body for
engagement
therewith.
According to a second aspect of the invention there is provided an air
filter for an exhaust fan cover having an open end with a perimeter sized to
surround
a recess in which an exhaust fan is mounted and at least one opening in the
exhaust
fan cover, the filter comprising:
a frame arranged for support on the exhaust fan cover; and
a layer of air permeable filter material supported by the frame such that
portions of the layer of air permeable filter material are unobstructed by the
frame to
allow air to flow through the at least one layer at those portions, the frame
and the
layer of air permeable filter material being arranged to position the
unobstructed
portions thereof between the at least one opening and the open end to force
airflow
between the at least one opening and the open end to pass through the
unobstructed portions of the layer of air permeable filter material.
According to a third aspect of the invention there is provided an air
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filter kit for exhaust fan covers of a type having an open end with a
perimeter sized
to surround a recess in which an exhaust fan is mounted and at least one
opening in
the exhaust fan cover, the air filter kit comprising:
a piece of air permeable filter material;
at least one template dimensioned for placement over the piece of air
permeable filter material to define a guide for cutting of the piece of air
permeable to
reduce at least one dimension thereof to fit the piece of air permeable
between the
at least one opening and the open end of an exhaust fan cover of known
dimensions
to force airflow between the at least one opening and the open end to pass
through
the piece of air permeable filter material.
Preferably the at least one template comprises a plurality of templates,
each template being smaller than the piece of air permeable filter material
and
dimensioned for cutting of the piece of air permeable filter material
therealong to fit a
respective one of differently dimensioned exhaust fan covers.
Preferably there is provided a perforated biocking member, of greater
rigidity than the piece of air permeable material, arranged for positioning
between
the piece of air permeable filter material and the recess to block motion of
the piece
of air permeable filter material past the blocking member while allowing
airflow
therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the present invention will now be described
in conjunction with the accompanying drawings in which:
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Figures 1 A and 1 B are top plan and side elevational views respectively
of a first type of prior art exhaust fan cover.
Figures 2A and 2B are top plan and side elevational views respectively
of a second type of prior art exhaust fan cover.
5 Figure 3 is an isometric view of a third type of prior art exhaust fan
cover.
Figures 4A, 4B and 4D are top plan, end elevational and side
elevational views respectively of an air filter according to the present
invention for an
exhaust fan cover of the type shown in Figure 1. Figure 4C is a partial cross
sectional view taken along line C - C of Figure 4A.
Figures 5A, 5B, 5D and 5E are top plan, end elevational, side
elevational and bottom plan views respectively of an air filter similar to
that of Figure
4. Figure 5C is a partial cross sectional view taken along line C - C of
Figure 5A.
Figure 6A, 6B and 6C are isometric, top plan and side elevational
views respectively of an air filter according to the present invention for an
exhaust
fan cover of the type shown in Figure 3.
Figure 7 is an overhead plan view of an exhaust fan covering kit
according to the present invention featuring an exhaust fan cover of the type
shown
in Figure 2.
Figure 8 is a cross sectional view of the exhaust fan covering kit of
Figure 7 as taken along line 8- 8 thereof.
Figure 9 is a cross sectional view, similar to that of Figure 8, of an
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alternate embodiment of an exhaust fan covering kit.
Figure 10 is an overhead plan view of an exhaust fan cover according
to the present invention.
Figures 11 A, 11 B, 11 C and 11 D are top plan, side elevational, end
elevational and bottom plan views respectively of another air filter for an
exhaust fan
cover of the type shown in Figure 1. Figure 11 E is a partial cross-sectional
view as
taken along line E - E of Figure 11 A.
Figures 12A and 12B are top plan and side elevational views
respectively of another air filter for an exhaust fan cover of the type shown
in Figure
3. Figure 12C is a partial cross-section view as taken along line C - C of
Figure
12A.
Figure 13 is a schematic illustration of an exhaust fan filter kit adapted
for use with any user-selected one of a number of standard exhaust fan cover
shapes and sizes.
Figure 14 is a cross-sectional view of a foam block of the exhaust fan
filter kit of Figure 13 having been installed on an exhaust fan cover of the
type
shown in Figure 1.
In the drawings like characters of reference indicate corresponding
parts in the different figures.
DETAILED DESCRIPTION
Figures 1 to 3 show three different types of conventional covers for
ceiling mounted exhaust fans. The present invention relates to providing these
and
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similar types of covers with an air filtering function to prevent build-up and
clogging
of an exhaust fan.
The tapered cover 10 of Figure 1 features a rectangular horizontal
base 12 defining a bottom surface of the cover. From each side edge of the
rectangular base 12 protrudes an inverted trapezoidal side wall 14 extending
obliquely outward and upward from a vertical plane in which the side edge is
situated. Each inverted trapezoidal side wall 14 is connected to adjacent side
walls
at its opposite non-parallel ends 16 and connected to the base panel at the
shorter
of its two parallel sides 18A. The cover body 20 formed by the base 12 and
side
walls 14 thus outlines an inverted frusto-pyramidal volume having an open top.
The
longer of the two parallel sides 18B of each side wall 14 defines a respective
linear
segment of this rectangular open top. Slot-like openings 22 extend along each
side
wall 14 to allow air flow through the cover body 16 as required for the
operation of
the exhaust fan (not shown) to be concealed by the cover 10. Hangers 24 are
connected to the base 12 to extend upward therefrom to hang the cover body 20
from respective brackets (not shown) provided in the mounting recess of a
conventional ceiling exhaust fan.
The non-tapered cover 40 of Figure 2 features a rectangular horizontal
base 42 defining a bottom surface of the cover. From each side edge of the
rectangular base 42 protrudes a rectangular side wall 44 extending
perpendicularly
upward therefrom. Each side wall 44 is connected to adjacent side walls at its
opposite ends 46 and connected to the base panel at one its two sides 48A. The
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cover body 50 formed by the base 42 and side walls 44 thus outlines a
rectangular
volume having an open top. The side 48B of each side wall 14 opposite the base
42
defines a respective linear segment of this rectangular open top. Slot-like
openings
52 extend along the base 52 to allow air flow through the cover body 16 as
required
for the operation of the exhaust fan (not shown) to be concealed by the cover
40.
Hangers 54 are connected to the base 42 to extend upward therefrom to hang the
cover body 50 from respective brackets (not shown) provided in the mounting
recess
of a conventional ceiling exhaust fan.
Figure 3 shows another type of cover 110 having a rectangular
horizontal base 112 and four legs 114 extending upward from the base, one at
each
of the four corners thereof. A rectangular collar 116 extends about and
interconnects the four legs 114 to delimit an open top of the cover for
communication
with a ceiling recess in which a fan is mounted. Each pair of adjacent legs
114
cooperates with the collar 116 and the base 112 to delimit a slot-like opening
118
through which air can pass to reach the fan (not shown) to be concealed by the
cover. Hangers 120 are arranged for connection to opposite sides of the collar
116
to suspend the cover body formed by the base 112, legs 114 and collar 116
immediately beneath the ceiling recess in which the fan is mounted.
Figure 4 shows an air filter 60 for use with a fan cover of the type
shown in Figure 1. The filter features four inverted trapezoidal panels 62
similar in
size and shape to the side walls 14 of the cover 10. The panels 62 are
oriented and
positioned relative to one another in the same fashion as the walls of the
cover, but
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the filter 60 does not feature a bottom panel analogous to the base 12 of the
cover.
As a result, the inverted frusto-pyramidal volume outlined by the panels 62 is
open
both at the top and bottom so as to define an opening 64 through the filter.
The
opening 64 is large enough to allow lowering of the filter onto the cover by
passing
the hangers 24 through the opening to bring the filter 60 into a nested
position atop
the cover 10. In such a position, each panel 62 sits on a respective side wall
14 of
the cover and extends over enough surface area thereof to cover the openings
22.
The air filter 60 features a frame and at least one layer of air
permeable filtration material 68. The frame is made up of an upper lattice, or
web,
70 nested partially within a lower lattice 72. Between the two lattices is the
one or
more layers of filtration material 68. Each lattice features an outer
perimeter 74
extending about and disposed upward from an inner perimeter 76, with a
plurality of
ribs 78 extending therebetween. As illustrated, there may be provided a middle
perimeter 80 disposed between the inner and outer perimeters. Openings
outlined
by the perimeter members and ribs allow air passing through the openings 22 of
the
fan cover 10 to proceed through the filtration material 68 toward the fan
being
concealed by the cover 10 and protected from build-up and clogging by the air
filter
60. The two frame lattices and the filtration material are held in sandwiched
relationship by clips 79 connecting the lattices at the corners thereof. In
Figure 4,
the upper and lower lattices are identical, and thus share the same
dimensions. As
shown, this results in the top of the upper lattice being situated at a higher
elevation
that the top of the lower lattice when the two are nested. Only one side
elevational
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view and one end elevational view are shown, but the two side views are
identical,
as are the two end views. For embodiments where the perimeters are square, the
side and end views would also be identical.
Figure 5 shows an air filter 60' similar to the filter 60 of Figure 4, except
5 that the upper and lower lattices are not identical. The upper lattice 70'
is smaller in
overall width and height than the lower lattice 72'. More specifically, the
outer
perimeter 74' of the upper lattice 70' is smaller than that of the lower
lattice, but
since the inner perimeters delimit equal areas, the ribs 78' of the upper
lattice 70' are
correspondingly shorter than those of the lower lattice. The result is that
the outer
10 perimeters of the two lattices are spaced apart by the filtering material,
but lie in a
common horizontal plane so that the upper lattice nested in the lower lattice
does
not protrude upward therefrom. Respective segments of the inner perimeters of
the
two lattices lie in a common vertical plane due to the same size of the two
inner
perimeters. The ribs of the two lattices could be equal in length if the inner
perimeter
76' was reduced in the same manner as the outer perimeter, which would have
the
similar result of positioning the inner perimeters within a common horizontal
plane.
Clips 79' hook the two lattices together at their outer perimeters between
their ribs.
Like the filter of Figure 4, only one side elevational view and one end
elevational
view are shown, but the two side views are identical, as are the two end
views.
The similar filters of Figures 4 and 5 each have their advantage. While
having the lattices end in a common horizontal plane at the top of the filter
may
provide a better balance between fully covering the inverted trapezoidal
panels of
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the cover and fitting within the cover's vertical dimensions, using two
identical
lattices may lower manufacturing costs.
Figures 7 and 8 show an exhaust fan covering kit 90 featuring a cover
40 of the type shown in Figure 2. The cover 40 has been provided with clips 92
protruding upward from the base 42 between the hangers 54 and outward from the
openings 52 to secure an air filter 94 onto the cover body in a position
covering the
slot-like openings 52. The air filter 94 features a frame and at least one
layer of air
permeable filtration material 96. The frame again is made up of an upper
lattice, or
web, 98 and a lower lattice 100. As the openings 52 in the cover body are
located
generally centrally thereon, that is on the base 42 between the hangers 54,
rather
than along the perimeter of the cover body outward from the hangers as in the
cover
of Figure 1, the air filter 94 does not require an opening therein through
which the
hangers can be passed. As a result, each lattice features a perimeter 102 and
a
plurality of cross members 104 extending between opposite sides of the
perimeter.
Each lattice thus defines a two-dimensional array of openings allowing
exposure of
the filtration material 96 to air. Air flowing through the openings 52 in the
cover body
is allowed to pass through the filtration material to trap airborne substances
and
prevent build-up at the fan. The clips 92 engage the upper lattice of the
frame at the
perimeter thereof to fasten the air filter to the cover.
As shown in Figure 9, it may not be necessary to provide a lower
lattice on the air filter, as the filtration material 96 may sit directly upon
the base 42
of the cover body for exposure to the air passing through the openings 52.
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Figure 6 shows an air filter 130 for the type of exhaust fan cover 110
shown in Figure 3. The air filter features an outer lattice 132 and an inner
lattice 134
with at least one layer of air permeable filtration material 136 disposed
therebetween. Each lattice is a fence-like structure having an upper perimeter
member 138 and a lower perimeter member 140 connected by ribs 142, the upper
and lower perimeters being vertically spaced and having the same dimensions.
The
perimeter of the inner lattice 134 is smaller than that of the outer lattice
such that the
inner lattice is disposed concentrically within the outer lattice with the
filtration
material 136 housed between them. The filter 130 is sized to sit upon the base
112
of the cover 110 with its corners fitting into those defined by the right-
angle legs 114
extending upward from the base to the collar 116. In this arrangement, each
opening 118 in the cover body is covered by a respective rectangular panel of
the
filter 130 formed by one side of the outer lattice 132, a respective side of
the inner
lattice 134 and the filter material 136 housed therebetween. Ties 144 spaced
about
the filter at the corners thereof and each wound tightly around the lattices
illustrate
that the layered arrangement of the lattices and filtering material may be
held
together by inter-lattice connections other than clips.
The air filters of the present invention may be marketed in a number of
possible ways. An air filter may be provided as part of an exhaust fan
installation kit,
as part of a replacement exhaust fan covering kit or as alone as an addition
for an
existing exhaust fan cover. In kit packages, the cover may include releasable
fasteners for selectively attaching and detaching the cover and air filter.
For
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example, the covers of Figures 1 and 3 may be provided with clips, like those
of
Figures 7 to 9, extending upward from the base panel to latch onto the filter.
It
should be appreciated that such clips would be situated inward from the
openings
with the engaging shoulders of the clips extending outward to catch on the
inner
perimeter of the filter. Alternatively, such clips could be provided on an air
filter,
which would allow the filter to be sold either as an add-on for an existing
cover or as
part of a kit including a cover. Such an arrangement is shown with broken
lines in
Figure 8. The filter clips 92A extend downward from the lower lattice 100 of
the filter
94 so as to be passable through respective ones of the openings 52 in the base
42
of the cover body to engage therewith.
Various air filter materials are known, and include paper, synthetics,
foam, cotton and statically charged elements. For example, the one or more
layers
of filtration material in the filters of the present invention may include a
single layer of
one material, such as foam, disposed between two statically charged elements
which attract charged particles to improve retention of unwanted materials.
The air
filters may be washable to extend the lifespan of the filter through cleaning
and
reuse. As described above, the filters and covers may be arranged to allow
removal
of the filter from the cover for cleaning or replacement. Alternatively, the
air filter
may be built-in to the cover itself, as conventional cover hangers allow quick
and
easy removal of the cover from over the fan's mounting recess; meaning that
the
entire cover could simply be removed for cleaning or replacement as needed.
Figure 10 shows a one-piece cover and air filter 150 having a shape
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similar to the conventionai cover of Figure 1. A plurality of openings extend
along
the perimeter of the cover body in the side panels 152 outward from the
central base
panel 154 on which the hangers 156 are supported. A layer of filtering
material 158
is supported by the cover body to extend over each of the openings
therethrough.
While multiple openings are shown in each of the side panels 152, just like
the filter
60 of Figure 4, it should be appreciated that fewer and larger openings could
be
used, for example one opening per side panel. In this one-piece embodiment,
the
exhaust fan cover body may be of a two-piece construction sandwiching the
filter
material between two halves of the cover body, much like the add-on filter
embodiment of Figure 4 but with a solid central base panel 154 closing the
bottom of
the structure at the center thereof, as shown in Figure 10, to force air to
pass
through the filter covered openings at the side panels. A similar one-piece
cover
and filter could be made in the style of the conventional cover of Figure 2,
for
example having filter material mounted to the cover body in a position over as
little
as one large central opening, or a plurality of smaller openings or slots as
shown in
Figure 2, in the base.
It should be appreciated that the present invention may be applied to
exhaust fan covers of other styles and other mounting arrangements. For
example,
the filters of the present invention may be used with covers not horizontally
mounted
as in a ceiling exhaust fan, for example a wall-mounted exhaust fan where the
cover
is oriented vertically against a vertical wall into which an exhaust fan has
been
recessed and mounted. Fasteners other than clips may be used to secure filters
to
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exhaust fan cover bodies.
Filter frames of other constructions known to those of skill in the art
may be applied in place of the layered lattice and filter material
arrangement.
Figure 11 shows a filter 160 for use with a cover of the type shown in
5 Figure 1. The frame of the filter consists of an upper collar 162 extending
about the
outside perimeter of the filter and housing the upper edge of the filtering
material
layer(s) and a lower collar 164 extending about the inside perimeter of the
filter and
housing the lower edge of the filtering material layer(s). As shown in the
cross
section of Figure 11 E, the collars are generally U-shaped in cross section to
receive
10 the filtering layer(s) between the legs of each cross section, the legs of
the two U-
shaped cross sections extending toward one another. In other words, the filter
material is received in and secured to the open end of the U-shaped cross
section of
each frame collar. Only one side elevational view and one end elevational view
are
shown, but the two side views are identical, as are the two end views. For
15 embodiments where the perimeters are square, the side and end views would
also
be identical.
Figure 12 shows a filter 170 for use with a cover of the type shown in
figure 3, but with a collar style frame like the filter of Figure 11. The
frame of the
filter 170 consists of an upper collar 172 extending along the perimeter of
the filter at
the top thereof to house the upper edge of the filtering material layer(s) and
a lower
collar 164 extending along the perimeter of the filter at the bottom thereof
to house
the lower edge of the filtering material layer(s). As shown in the cross
section of
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Figure 12C, the collars are again generally U-shaped in cross section to
receive the
filtering layer(s) between the legs of each cross section, the legs of the two
U-
shaped cross sections extending toward one another. In other words, the filter
material is received in and secured to the open end of the U-shaped cross
section of
each frame collar. Only one side elevational view is shown, but it should be
appreciated that due to the square perimeter of the filter 170, all sides have
an
identical appearance. The top and bottom views of the filter are also
identical.
To retain their shape, filters using collar-style frames may either use
filtering material of sufficient stiffness to retain the relative positioning
of the upper
and lower collars or provide stiffening or reinforcement members extending
between
the collars. For example, the collars may be used in conjunction with lattices
disposed on opposite sides of each segment of the filtering layer(s), the U-
shaped
cross section of the collars housing both the filtering material and the
lattices, webs
or grids between them in the open side of the U-shaped cross section.
Where lattices, or webs, are used in a layered configuration, they may
be connected by elements other than clips, ties or collars. The frame elements
may
be made of plastic, wire or other suitable material known to those of skill in
the art.
Although described herein above in the context of fan covers for ceiling
mounted
fans, the present invention may be adapted for use with other mounting
arrangements, for example exhaust fans recessed into a vertical wall. An air
filter
may be arranged to simply rest atop the exhaust fan cover rather than being
fastened thereto. For example, in embodiments where the filter horizontally
extends
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close enough to the outer perimeter of the cover so as to extend past the
opening of
the recess in which the fan is mounted and vertically extends to the top the
cover,
the filter would be effectively clamped against the cover openings by the
cover and
the surface from which the fan is recessed, for example a ceiling.
Figure 13 shows an exhaust fan filter kit 200 made up of a rectangular
foam block 202 and two rectangular templates 204, 206 each made of a thin
plate of
rigid material. The sizes of the foam block and the two templates correspond
to
standard different sizes of exhaust fan covers available on the market, as
represented in the figure by the three conventional cover types 10,40,110
described
herein above and pictured separately in Figures 1, 2 and 3 respectively. In
Figure
10, the foam block 202 is initially dimensioned to fit snugly between the four
legs 114
atop the rectangular base 112 of cover 110 so that the four side edges 202a
between the two parallel end faces 202b of the block 202 fit against the slot-
like
openings 118 extending along the edges of the rectangular base 112 between the
legs 114 projecting upward at the corners thereof. The block is of sufficient
thickness to cover the full height of the openings 118. The block thus covers
the
openings so that any airflow drawn through the openings 118 toward the exhaust
fan
through the open top end of the cover 110 is forced to pass through the air-
permeable foam, which acts to filter particulate matter from the air. If the
purchaser
or other end user of the kit wishes to use it on a smaller exhaust fan cover,
as
represented by the tapered cover 10 in the Figure, then the corresponding
template
204 is laid flat on a face 202b of the block 202 so as not to project past any
edges
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thereof, and a cutting blade is used to cut the foam block 202 along the edges
204a
of the flat template 204 to reduce the size of the block to that suitable for
mounting in
that particular cover 10. If the user wishes to instead install a filter on an
even
smaller exhaust fan cover, as represented by cover 40 in the figure, then the
smallest template 206 is instead laid on the face 202b of the block and cut
around to
reduce the block size to dimensions appropriate to fit that particular cover.
The
same filter kit can thus be used to equip any of a plurality of differently
sized exhaust
fan covers with a filter.
Figure 14 shows the foam block 202 having been cut down using the
larger template 204 and installed in the tapered cover 10. The resulting
length and
width dimensions of the block's face 202b are such that the block 202 is
supported
by the sloped trapezoidal side walls 14 projecting obliquely outward from the
rectangular base 12 upward therefrom so that the top face is disposed
substantially
flush with the open top end of the cover 10. This way the slot-like openings
22 in the
side walls 14 are disposed below the foam block 202 so that airflow between
the
slots 22 and the open top end of the cover 10 is forced to pass through the
filtering
foam block. Even if the thickness of the foam block is such that it extends
downward
from the open top of the cover fully or partially past the uppermost of the
slots 22,
the template is sized to be slightly larger than the open top end of the cover
10 and
this overlap or interference fit cooperates with the flexibility and
resiliency of the
foam to ensure a good seal between the foam block 202 and the upper ends of
the
angled side walls 14 above the uppermost slot. This prevents airflow from
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bypassing the filter through gaps left between the foam and the cover. This
positioning of the foam block illustrates that the filters of the present
invention need
not necessarily be placed directly over the openings in the exhaust fan
covers, but
instead must be placed somewhere between the openings and the open upper end
in a way that extends fully across communicating space therebetween. This may
be
achieved by mounting the filtering material to cover all the openings, as in
the
embodiments of Figures 3 to 12, or by mounting the filtering material to cover
the
open upper end as shown in Figure 10. As the perimeter of the open upper end
extends around the recess in which the exhaust fan is installed in flush
engagement
with the surrounding surface when the cover is mounted in place, passage of
air into
the recess to the exhaust fan is basically limited to flow through the
openings in the
fan cover and upward through the open upper end thereof. Positioning the
filter
material fully across the openings or open upper end limits fluid
communication
therebetween to passage through the filter material.
Figure 14 also shows that where a resilient filter material such as foam
is used, wire hangers conventionally used to support an exhaust fan cover over
the
opening of the fan-containing recess can simply be manually passed through the
filter material by the installer without significant detriment to the
effectiveness of the
filter, as the resiliency of the material will tend to seal the filter
material around the
wire hanger so passed therethrough. The smaller template 206 may therefore be
sized small enough to fit the foam block between the hangers 56 of cover 40
(see
Figure 2) or my instead be sized to have the foam block 202 resiliently engage
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against the rectangular side walls 44 projecting upward from the rectangular
base
42, to better hold the block in place thereatop, once having the wire hangers
54
pushed therethrough and being fed down thereover onto the base 42.
As shown in Figure 13, the kit 200 may also include a flat rectangular
5 plastic or wire mesh or grid 208 of slightly larger dimensions than the foam
block
202. The mesh 208 has greater rigidity than the foam block 202 so that it can
be
positioned to cover the recess which the foam-equipped fan cover is to be
positioned
over to prevent the flexible foam block from being sucked into the recess
toward the
exhaust fan mounted therein. The grid 208 thus defines a relatively rigid
blocking
10 member having a series of openings or perforations therein to block the
relatively
flexible foam block 202 from passing by it toward the exhaust fan while
allowing
airflow through it. Like the foam block, the grid may be cut down in size by
the
installer of the fan cover to fit within the perimeter of the open upper end
of a specific
fan cover while spanning fully across the opening of the recess in the ceiling
or other
15 surface in which the fan is mounted. The openings in the grid 208 are each
sufficiently small to prevent the foam block from being pulled therethrough
under
operation of the exhaust fan.
Figure 14 shows the blocking member grid 208 positioned atop the
foam block 202 at the open upper end of the tapered exhaust fan cover 10. The
grid
20 208 has been cut to fit just within the rectangular perimeter of the open
upper end to
extend fully between the opposite side panels 14 of the cover 10, as defined
by the
longer sides 18b of the inverted trapezoidal side walls 14. So positioned, the
grid
CA 02602631 2007-09-11
21
208 will extend fully across the opening of the fan-containing recess past the
opposite sides thereof when the fan cover 10 is hung in place, so that any
lifting
tendency of the foam block 202 from the cover 10 toward the exhaust fan in the
recess is blocked by contact of the grid 208 with the surface into which the
recess
extends at points surrounding the opening thereto. As shown, the openings in
the
grid 208 allow the hangers 24 of the exhaust fan cover 10 to pass therethrough
to
suspend the cover from the recess in a known fashion. Like for the foam block
202,
templates may be provided for cutting the grid 208 down to a predetermined
size to
properly fit with a known size or style of exhaust fan cover.
It should be appreciated that although Figure 13 shows two templates,
a kit for use with exhaust fan covers of different sizes may feature a
different number
of templates. For example, where the block of foam is dimensioned to fit a
particular
size or style of cover right out of the box, providing only a single template
will still
allow use of the same kit with either of two different sizes. On the other
hand, more
than two templates may be provided to facilitate use of the kit among a wider
selection of covers. Filtering materials other than foam may be used in the
adaptive
kit of Figure 13, with flexible resilient materials having the potential
advantages of a
snug fit with the cover and the option of passing wire hangers through the
material
without requiring preformed openings to maintain a good seal and maximize the
percentage of air flow through forced to pass through the filter material.
Although
shown as rectangular plates, templates of different shapes may be provided to
cut
the foam block into pieces of particular shape to fit within correspondingly
shaped
CA 02602631 2007-09-11
22
exhaust fan covers. For example, the foam block may cut into four separate
trapezoidal pieces to individually fit directly over the side panels 14 of the
tapered
fan cover 10, with the grid 208 being cuttable into similar shapes for
individual
fastening to the fan cover over the respective foam pieces, for example by tie
straps
tied around cross members through the openings in the fan cover.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without department from such spirit
and
scope, it is intended that all matter contained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
