Note: Descriptions are shown in the official language in which they were submitted.
CA 02143984 1999-06-22
-1-
FILTER SYSTEM
Field of the Invention
The present invention relates to filter systems in general and, in particular,
to
a storm drain filter system for filtering sediments and contaminants from
liquid
flowing therethrough.
Background of the Invention
Environmental awareness is rapidly increasing as scientists and others
consider the effect pollution is having on rivers, lakes, and oceans and
underground
water supplies. These bodies of water are inundated with pollution stemming
from a
number of sources, including factories, food processing and surface water run-
off
that enters the bodies of water through storm drains, carrying herbicides,
pesticides,
petroleum, and other pollutants that have been collected along the way.
A number of filter systems have been proposed and are currently being used
in factories in an attempt to filter processing water that is polluted through
manufacturing operations. Filter systems have also been proposed for storm
drains,
but their use has been limited, apparently due to inconvenience, cost, and the
lack of
governmental regulations that would require the removal of contaminants from
run-
off water and other liquids flowing through a storm drain system. However, as
more
emphasis is being placed upon protecting the environment, greater effort in
removing
HOJI\8302CL.DOC
CA 02143984 1999-06-22
-2-
contaminants from water run-off, processing liquids, and other liquids is
being emphasized. There
is a continuing need for an efficient, cost-effective filter system that will
remove sediments and
contaminants from liquids while allowing aeration to occur and minimizing the
work required to
maintain the filter system.
Summary of the Invention
The invention is a filter system for filtering a liquid medium, the filter
system
having filter material to treat liquid flowing through an inlet opening
leading into the filter
system, comprising: (a) a housing having a peripheral wall defining a filter
chamber therein, the
l0 filter chamber including an inlet for inflow of liquid entering the inlet
opening of the filter
system and an outlet for discharging the liquid from the filter chamber, the
housing having
means for supporting the housing within the opening of the filter system to
occupy substantially
the entire opening of the filter system; (b) a removable rack for placement
within the filter
chamber of the housing, the rack being movable between a first position
received in the filter
chamber and a second position removed from the filter chamber; (c) one or more
filter
components, each filter component supporting a quantity of the filter
material, the filter
components being structurally independent of and normally held by the rack in
the path of liquid
flow, and being separable from the path of liquid flow when the rack is in the
second position;
(d) means for directing into the housing substantially all of the liquid
medium entering in the
2 0 filter system opening; and (e) the filter components having an outer
perimeter configured to
define a gap between the filter components and the peripheral wall of the
housing to allow
passage therebetween of overflow liquid from the filter components.
In accordance with another aspect the invention provides apparatus for
supporting
filter materials for treating liquid flowing therethrough, comprising: (a) a
housing comprising a
2 5 peripheral wall extending about the perimeter of the housing and
partitions to cooperate with the
perimeter wall to define a plurality of filter chambers therein, the filter
chambers including an
inlet for inflow of the liquid and an outlet for discharging the liquid; (b) a
plurality of filter
material supports, each filter material support housing a quantity of filter
material; (c) racks
dimensioned to fit into the filter chambers of the housing, each rack being
structurally
3 0 independent of the filter material supports, each rack being movable
between a first position
received in a filter chamber and a second position removed from the filter
chamber, each
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rack having means for holding the filter material supports in the path of
liquid flow when the
rack is in the first position and when the rack is in the second position the
filter material
supporting being liftable away from the corresponding rack to provide access
to the filter
material housed in the filter material supports; and (d) the filter material
supports sized to define
a gap between the filter material support and housing when the filter material
support is held by a
rack, the gap permitting overflow liquid from the filter material support to
bypass the filter
material.
In accordance with another aspect the invention provides a liquid medium
filter
system for a drainage system, the liquid drainage system having an outer
protective grating
supported on a ledge that extends around the perimeter of an opening to the
drainage system, the
filter system having absorbent materials positioned to filter liquid flowing
into the opening to the
drainage system, comprising: (a) a housing to be positioned within the
drainage system opening and
underneath the outer grating, the housing having a top that is nearest the
outer grating and a bottom
opposite the top, the housing having means for suspending the housing from the
perimeter ledge of
the suspending draining system opening to occupy substantially the entire area
of the drainage
system opening; (b) one or more filter components, each filter component
including means for
supporting the absorbent materials, the absorbent materials removing
contaminants and particulate
matter from liquid flowing into the drainage system and through the filter
system; (c) a removable
2 0 rack dimensioned to be receivable within the housing through the top of
the housing and including a
plurality of holding members that support the filter components, the rack
being structurally
independent of the filter components to removably support the filter
components, the housing and
the rack having cooperating members that in a first position are engaged to
support the rack within
the housing, and that in a second position are disengaged to allow the rack to
be removed from the
2 5 housing upwardly through the housing top to provide access to the filter
components, the rack
having manually graspable portions for grasping when engaging the rack with
and removing the
rack from the housing; and (d) the filter components sized to define a gap
between the filter
components and the housing when the filter components are supported in first
position within
housing by the rack, the gap permitting overflow liquid from the filter
component to bypass the
3 0 absorbent material supported by the filter components and flow toward the
bottom of the housing.
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CA 02143984 1999-06-22
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In accordance with a still further aspect the invention provides a filter
system to
be used in conjunction with a storm drain, the storm drain having an outer
grating supported on a
ledge that extends around the perimeter of the storm drain and a perimeter
wall extending into
the storm drain from the ledge, the filter system having filter material
positioned to filter liquid
flowing therethrough. comprising: (a) a first support structure, to be
positioned within the storm
drain, and underneath the outer grating, including side walls, a top grate,
and a bottom grate,
which define a housing for filter material, the first support structure
further including an
outwardly extending flange dimensioned to contact the ledge of the storm drain
when the first
support structure is placed into the storm drain beneath the outer grating;
(b) a second support
structure including side walls, a top grate, and a bottom grate which define a
housing for filter
material; (c) means for coupling the first and second support structures
wherein the second
support structure is suspended below the first support structure to filter
liquid after it has entered
the storm drain and passed through the first support structure; and (d) a gap
between the
perimeter wall of the storm drain and at least one of the first and second
support structures to
permit overflow liquid from the support structure to bypass the filter
material within the support
structure and flow into the storm drain.
Brief Description of the Drawings
The foregoing aspects and many of the attendant advantages of this invention
will
2 o become more readily appreciated as the same becomes better understood by
reference to the
following detailed description, when taken in conjunction with the
accompanying drawings,
wherein:
FIGURE 1 is an exploded perspective view of a first exemplary embodiment of a
filter system in accordance with the invention;
2 5 FIGURE 2 is a cross section of the filter system of FIGURE 1;
FIGURE 3 is a side perspective view of the filter system of FIGURE 1;
FIGURE 4 is an exploded perspective view of a second exemplary embodiment of a
filter system in accordance with the invention;
FIGURE 5 is an exploded perspective view of a third exemplary embodiment of a
3 0 filter system in accordance with the invention;
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CA 02143984 1999-06-22
-3b-
FIGURE 6 is an exploded perspective view of a fourth exemplary embodiment of a
filter system in accordance with the invention;
FIGURE 7 is an exploded perspective view of a fifth exemplary embodiment of a
filter system in accordance with the invention;
FIGURE 8 is a cross section of the filter system of FIGURE 7; and
FIGURE 9 is a cross section of a sixth exemplary embodiment of a filter system
in accordance with the invention;
62839-1692
l,' ~A ~ ~ ~ ~'~ ~ 4
-4-
FIGURE 10 is an exploded perspective view of a seventh exerrTplary embodiment
of
a filter system in accordance with the invention;
FIGURE 11 illustrates an eighth exemplary embodiment in accordance with the
invention which is similar to the filter system of FIGURE 1, except in which
trays are used to
house absorbent materials;
FIGURE 12 is an exploded perspective view of the trays illustrated in FIGURE
1;
FIGURE 13 illustrates a ninth exemplary embodiment in accordance with the
invention
which is similar to the filter system of FIGURE 7, except that the rack and
accompanying filter
components have been split into halves;
FIGURE 14 is a perspective view of the filter system of FIGURE 13;
FIGURE 15 is a tenth exemplary embodiment of a filter system in accordance
with the
invention; and
FIGURE 16 is a cross section of the filter system shown in FIGURE 15.
Detailed Description of the Preferred Embodiment
FIGURES 1-3 illustrate a first exemplary embodiment of a filter system 10 in
accordance with the invention. Filter system 10 includes a housing 12, a
removable rack 14
that holds a plurality of expanded gratings (grates) 16, and a plurality of
containers 18 for
holding absorbent materials used to remove contaminants from liquid flowing
through the
filter system. The filter system 10 may be used in a number of environments or
drainage
systems, for example, in a factory for filtering processing liquids and
underneath a storm
drain for filtering ground water run-off. Throughout the specification and in
the figures, the
filter system is shown in use within a storm drain, which is only one of the
preferred uses of
the filter system.
FIGURES 1-3 illustrate a typical storm drain 20 used by municipalities that
is, for
example, located along a curbside and coupled to a storm sewer system that
drains into a
body of water to be protected from contaminants. Storm drain 20 includes a
rectangular-
shaped ledge 22 that extends around the storm drain perimeter for supporting
an outer
grating 24. The filter system 1 O is dimensioned to fit into a typical storm
drain, beneath the
outer grating. Water and other liquid entering the storm drain will thus be
directed into the
filter system 10, through the containers 18 and subsequently out of the filter
system. As is
shown in FIGURE 3, the rack 14 is removable to allow absorbent material housed
in the
containers to be easily replaced and subsequently recycled.
The housing 12 is illustrated as having four sides that define a rectangular-
shaped filter
chamber 26 having a top inlet 28 adjacent the outer grating 24 of the
tA~ i 4'984
-5-
storm drain, and a bottom outlet 30 for discharging liquids into the storm
drain system. An
outwardly extending flange 32 extends around the upper perimeter of the
housing. The
flange 32 is dimensioned to rest on the ledge 22 of the storm drain, just
below the outer
grating 24. Two oppositely disposed, inwardly extending flanges 34 are
provided at the
bottom of the housing for use in supporting the rack 14. In some applications,
it is desirable
to enclose the bottom of the housing 12 with a grating or mesh screen. The
housing 12 is
preferably constructed of a noncorrosive, but high-strength and lightweight,
material, such
as stainless steel, aluminum, fiber glass, or plastic.
The rack 14 includes two formed, generally U-shaped side members 35, each
including
a pair of legs 36. The side members are coupled together by a plurality of
cross members 38.
The rack is dimensioned slightly smaller than the inner walls of the housing
such that the rack
fits into the filter chamber 26 with the legs 36 resting on the inwardly
extending flanges 34
of the housing. A top pair of cross members 38a and 38b provide handles to
allow the rack
14 to be conveniently lifted from the housing, as is shown in FIGURE 3. The
remaining cross
members 38 are positioned in pairs on opposite sides of the rack to span
between
corresponding legs 36 of the side members 35 to provide supports for the ends
of the grates
16 and hold the grates substantially parallel to the top of the housing 12. In
this manner, the
grates are generally held in an orientation that is perpendicular to the flow
of liquid through
the filter system. An example of suitable material for the legs 36 and cross
members 38 is
quarter-inch diameter stainless steel that is cut, welded and bent to form the
shape illustrated
in FIGURES 1-3.
The grates 16 each include a rectangular-shaped mesh surface 40 composed of a
suitable material such as stainless steel, aluminum or plastic. The surface 40
is supported
around its perimeter by a pair of parallel side bars 42 and a pair of parallel
end bars 44. The
grates 16 are slightly longer and narrower than the rack 14. The side bars 42
are slightly
longer than the grate, with each side bar 42 including a downwardly extending
portion at the
ends thereof that form tabs 46 that cooperatively engage the cross members 38
of the rack
when the grate is positioned within the rack. Suitable materials for the mesh
filter surface
40 are expanded metal or hardware cloth. However, the mesh filter surface can
also be
composed of a plastic material.
Each grate 16 supports one or more of the containers 18, which are filled with
absorbent materials. The size of the apertures in the grates will, to an
extent, determine the
rate of liquid flow through the filter system and the type and size of
!'A~ I 4 ;~~~q.
-6-
debris that is collected on the grates, as opposed to being filtered through
the filter system.
The size of the grate apertures could decrease from top to bottom so that
larger debris is
collected at the top of the filter system. As will be appreciated by those
skilled in the art, a
wire mesh screen or geotextile fabric such as AmocoT"" geotextile nos. 4535,
4545, 4551
may be used in addition to or as one or more of the grates 16 to collect
smaller particles of
debris, sediment, and dirt. If a screen alone is used, it is preferably
supported around its
perimeter with side and end bars similar to those depicted in FIGURE 1.
The containers 18 are preferably slightly longer and wider than the grates 16
such that
when the rack is positioned within the housing, the containers 18 contact the
sides of the
housing to prevent liquid from flowing between the containers and walls of the
filter chamber
26. Preferably, each container has an opening through which spent absorbent
materials may
be removed and replaced with new or recycled materials. The opening is
releasably closed
by, for example, a hook and latch mechanism such as that sold under the
trademark
VELCROT"". The container may also be closed by providing a slide fastener (not
shown) at
an end thereof or through other means known in related arts.
The containers 18 may be composed of a porous, supple mesh fabric or other
porous,
non-corroding, inert material to permit the entry of liquid flowing through
the filter system.
Suitable materials for this use is nylon or a geotextile fabric. Each
container houses material
that is capable of absorbing contaminants from liquid flowing through the
filter system.
When filled with absorbent material the containers resemble a pillow shape.
For example, the
containers may include a layer of activated charcoal, activated carbon,
Absorbent WT"", or
other product as desired, depending upon the types of pollutants to be
collected. Absorbent
WT"" is a product available from the Total Absorbent Company and is especially
useful in
absorbing petroleum products. Other products such as activated charcoal or
sand are
available that absorb herbicides, pesticides, chemical fertilizers and other
contaminants to be
collected. It will be appreciated that the types and amounts of absorbent
materials used will
depend on the types and amounts of pollutants in the liquid being filtered.
Further, the
relative location of the materials will also depend on these factors. For
example, it may be
desirable to place the Absorbent WT"" above the charcoal or other absorbent
materials. The
size of the containers 18 on the vertical spacing between the grates 16 can be
varied to
accommodate the size (volume) and quantity of the containers 18.
As will be appreciated, the filter system 10 provides an economical and safe
method
of collecting contaminants from liquids such as storm and surface water run-
JA2 i 4W34
_,_
off flowing into storm drain systems and processing liquids. Collection points
and sources
of such liquids are industrial areas, parking lots, streets, construction
sites and manufacturing
operations. In an actual embodiment of the present invention, the filter
system has a
maximum rate of liquid flow on the order of about 200 gallons per minute per
square foot of
filter system surface area. The filter system has been found to effectively
remove at least
89 percent of harmful contaminants, such as gasoline and other fuels,
pesticides, and
herbicides, at this rate of flow.
It has been found that when the uppermost grate is flat, debris may collect
across the
surface of the grate, substantially reducing the flow of liquids through the
filter system. To
reduce this problem, the filter system 10 may be configured with an uppermost
grate that will
provide a collection point for the debris and yet allow liquids to freely flow
through the filter
system. FIGURES 4-6 illustrate exemplary embodiments of an uppermost grate and
rack that
will minimize the effect of debris on the filter system.
FIGURE 4 illustrates a second exemplary embodiment of the filter system 10,
including
a trough-shaped, uppermost grate 50 that is supported in an inverted
orientation by a rack
52. The grate 50 includes a substantially flat, longitudinal middle section 54
that extends
substantially across the length of the housing /not shown) when the grate is
positioned
therein, and side sections 56 that slope downwardly from the middle section
54. Preferably
the width for the middle section is about 40 to 60 percent of the total width
of the grate 50.
Given this width, the side sections extend downwardly at a slope of about
forty-five degrees
relative to the middle section 54. Preferably, the lower edge of each side
section 56 is
slightly upturned, forming a lip 60 along each side of the grate 50.
The rack 52 is similar to the rack 14 of FIGURES 1-3, except that the top of
the rack
is shaped to accommodate the grate 50. In that regard, the rack 52 includes
end sections
62 that are coupled together by a plurality of longitudinal support rods 64.
In addition to
supporting the end sections 62, the support rods provide a handle for removing
the rack from
the housing, after the uppermost grate 50 has been removed. The end sections
62 each have
two legs that extend upwardly from the housing, parallel to the sides of the
housing, until
reaching a height that corresponds to the lowest portion of the uppermost
grate 50, where
the legs extend toward the middle of the rack at a slope approximately equal
to the slope of
the side sections 56 of the uppermost grate 50. Thus, the upper portions of
the end sections
and the uppermost grate 50 are shaped similar to a truncated triangle of an
inverted
orientation.
'~ !'A~ i 43~~~4
_$_
Each of the end sections 62 include cross members 65 that extend across the
width
of the rack 52 and provide support to a plurality of additional grates 58 that
are substantially
the same as the grates 16 of FIGURES 1-3. Each of the additional grates
includes a mesh
filter surface 40, side bars 42, end bars 44, and projections 46. Containers
18 of absorbent
material are placed on the lower grates 58 prior to positioning the rack 52
and uppermost
grate 50 into the housing. Containers holding absorbent material are generally
not positioned
on top of the uppermost grate 50.
The uppermost grate 50 provides a two-fold purpose. First, debris entering the
storm
drain will tend to collect at the lower portions of the grate, leaving the
higher portions
unobstructed and free to pass liquid to the lower portions of the filter
system. Second, the
shape of the grate has a tendency to distribute liquid entering the filter
system across the
entire surface area occupied by the filter system, allowing greater filtering
capability. The lips
60 aid in collecting smaller debris, such as cigarette butts, that enters the
filter system but
that is too large to filter through the uppermost grate 50. Further, the lips
60 allow the
uppermost grate to be removed from a storm drain without the debris falling
into the storm
drain.
FIGURE 5 illustrates a third exemplary embodiment of the filter system 10,
wherein
an uppermost grate 66 is substantially triangular in cross section. Grate 66
includes a
longitudinal peak 68 and sides 70 that slope downwardly from the peak, toward
the housing
(not shown). As with the grate 50 of FIGURE 4, the lower edges of the sides 70
are
upturned to form lips 72. A rack 74 supports the grate 66 with two end
sections 76 that are
connected by longitudinal support rods 78. The rack 74 also includes cross
members 65 that
provide support to the lower grates 58. One of the longitudinal support rods
78 substantially
abuts the peak 68 of the uppermost grate 66 when the grate is positioned onto
the rack. The
upper portions of the end sections 76 support the sides 70 of the uppermost
grate 66 near
each end of the grate.
As will be appreciated by those skilled in the art, the grates 50 and 66 of
FIGURES
4 and 5 may be of other configurations that provide at least some of the
benefits described
in relation to the uppermost grates 50 and 66. Exemplary grates include
configurations that
have a slightly rounded uppermost section with flat sides or a configuration
wherein the entire
grate is substantially semicircular in cross section.
FIGURE 6 illustrates a fourth exemplary embodiment of the filter system 10. In
FIGURE 6, a rack 80 is configured to hold an uppermost grate 82 at a slope
having an angle
on the order of about 30 to 60 degrees relative to the horizontal. The rack 80
includes end
sections 84 that are coupled together by a plurality of
~'A~ I 43~~~4
_g_
longitudinal support rods 86. Each end section includes a pair of legs 88,
uppermost cross
members 90 that support the uppermost grate 82, and lower cross members 65
that support
the lower grates 58. The grate 82 is similar to grates 58, but is slightly
wider than the lower
grates to accommodate the increased distance between the legs 88 that results
from the
sloped orientation of the uppermost grate. Thus, the uppermost grate 82 will
nearly abut the
walls of the housing when the rack is positioned therein.
The embodiment of FIGURE 6 is designed to be placed in topographies in which
the
land surrounding the storm drain is at a slope relative to the storm drain.
The rack 80 and
uppermost grate 82 are preferably positioned such that liquid flowing into the
storm drain
enters the lowest part of the uppermost grate first. In this manner, the
liquid is directed
downwardly into the filter system rather than tending to flow across the
filter system.
FIGURES 7 and 8 illustrate a fifth exemplary embodiment of the filter system
10 in
which the grates 16 and containers 18 (shown in FIGURE 1 ) have been replaced
by grate
support structures 100 and a pair of top and bottom grates 104 and 106.
Instead of being
held within pillow-shaped containers 18, absorbent materials 108 are housed
within the
support structures 100 and grates 104 and 106. Preferably, a geotextile
material 107 is also
included along the lower grate 106 to help contain the absorbent material 108.
Other than
replacing the grates 16 and containers 18 shown in FIGURES 1-3 with grates 104
and 106
and support structures 100, the filter system shown in FIGURES 7 and 8 is
substantially the
same as the filter system shown in FIGURES 1-3.
Each support structure 100 includes four sides 1 10, two of which include a
pair of
side rails 1 12 for supporting the grates 104 and 106. To use the support
structures 100, the
bottom grate 106 is positioned onto the lower side rails 1 12, and the
geotextile fabric 107,
if used, is placed on the lower grate and along the sides 1 10 of the support
structure 100.
Absorbent materials 108 are then placed within the grate support structure
100, on top of
the geotextile fabric 107. The top grate 104 is then positioned onto the upper
side rails 1 12,
above the absorbent material. As is shown in FIGURES 7 and 8, the support
structures 100
may be various depths depending upon the amount of absorbent material that is
to be housed
therein. It will also be appreciated that a different number of the support
structures 100 may
be employed.
The support structures 100 prevent "bunching" of the absorbent materials that
sometimes may occur when the containers 18 are used. Further, liquid flowing
-10-
through the support structures 100 is less likely to drain between the edges
of the containers
and housing wherein it is not filtered by the absorbent materials in the
filter system.
It is noted that there are some applications, for example, at construction
sites and at
other outfalls, where filtering of contaminants is not required but in which
sediment filtering
is desirable. The filter system 10 of FIGURES 7-8 will best accommodate such
applications
by including a single one of the support structures 100, including the top and
bottom grates
104 and 106, and geotextile fabric 107, with the depth of the support
structure 100 being
increased to minimize maintenance (emptying) of the filter system.
FIGURE 9 illustrates a sixth embodiment of a filter system 120 that may be
used in
storm drains that are too shallow to accept the complete filter system 10
illustrated in
FIGURES 1-8. Filter system 120 comprises a support structure 122 which is
similar in
construction to support structure 100 shown in FIGURES 7 and 8, but including
an outwardly
directed flange 124 that extends around the upper perimeter of the support
structure 122 to
rest on the ledge 22 of the storm drain 20. Otherwise, the filter system 120
operates in the
manner similar to the filter system shown in FIGURES 7 and 8. Also, as with
the filter
system described in FIGURES 7 and 8, the filter system 120 may also be used to
collect
sediment only.
FIGURE 10 illustrates a seventh exemplary embodiment of a filter system 130 in
accordance with the invention. Filter system 130 comprises a support structure
132 which
is similar in construction to support structure 100 shown in FIGURES 7 and 8.
Support
structure 132 includes two outwardly directed flanges 134 that extend the
length of a pair
of sides 136 to rest on the ledge 22 of the storm drain 20 when the filter
system is in place.
The filter system 130 generally operates in the manner similar to the filter
system shown in
FIGURES 7 and 8.
The filter system 130 includes a pair of end walls 138 that, in conjunction
with the
sides 136, provide support for the grates 104 and 106. A pair of clips 139
holds the upper
grate 104 in place. Further, each end wall 138 includes a cutout portion 140
that allows
liquid to flow out of the filter system and into the storm drain should an
overflow condition
exist, e.g., if the filter system becomes clogged or otherwise drains too
slowly to
accommodate the flow of liquid entering the storm drain. The cutout portions
prevent
accumulation of surface liquid at the entrance of the storm drain during such
an overflow
condition. It is noted that in some applications, where it is imperative that
liquid not escape
the filter system without processing, it may be more advantageous to exclude
the cutouts
140, thereby allowing
~1~ ! ~~~r~W
-11-
the liquid to accumulate and subsequently drain at a flow rate conducive to
the filter system.
An alternative is to remove overflow liquid as it enters a type of cutout near
the location of
cutouts 140 for processing at an adjacent site or, if desired, even offsite.
The filter system 130 also includes a feature that helps to ensure liquids
entering the
storm drain are directed into the filter system 130, and thus do not escape
filtration by
seeping through the cutouts 140 or around the fringe of the filter system. A
funnel-like
diverter 142 includes a perimeter section 144 that rests on top of the flanges
134,
underneath the outer grating of the storm drain. Extending down and inwardly
from the
perimeter section 144 are walls 146 that direct liquids flowing into the storm
drain onto the
grate 104 of the filter system. The diverter is preferably a separate
component to facilitate
removal of the grate 104 and subsequent access to absorbent material housed
within the
filter system 130.
FIGURES 1 1 and 12 illustrate an eighth exemplary embodiment of the filter
system 10
that combines the features of the embodiments illustrated in FIGURES 1 and 7.
More
particularly, each of the containers 18 (shown in FIGURE 1 ) have been
replaced by a filter
component or tray 148 for holding absorbent materials. The trays 148 are
similar to the
grate support structures 100 but include structural differences that will
become apparent
from the discussion below. Further, in contrast to the embodiment of FIGURE 7,
the trays
148 rest on perforate plates, such as the grates 16, and not directly on the
cross members
38 of the rack 14. Finally, in a preferred embodiment of the invention, the
filter system
includes the diverter 142 that was described in reference to FIGURE 10. Again,
it is
advantageous for the diverter to be removable to facilitate removal of the
rack 36 and
accompanying hardware.
Preferably FIGURE 12 is an exploded perspective view of one of the trays 148.
Each
tray includes side walls 150, end walls 152, a bottom grate 154, a lower grate
156 and an
upper grate 158. The side and end walls 150 and 152 include pairs of side and
end rails 160
and 162, respectively, that hold the lower and upper grates 156 and 158. A
clip 164 is
positioned near the middle of each end wall to hold the upper grate in place.
To use the trays
148, the lower grate 156 is positioned onto the lower side and end rails 160
and 162, and
the geotextile fabric 107, if used, is placed on the lower grate and along the
sides of the tray.
Absorbent materials 108 are then placed within the tray, on top of the
geotextile fabric 107.
The upper grate 158 is then positioned onto the upper side and end rails 160
and 162, above
the absorbent material.
L ~1 ~ ! l+ > > ~ ~E
-12-
It is noted that the term "filter component" is used to refer to any means
described
herein or similar structure that provides support for filter or absorbent
materials, including:
(1 ) the combination of grates 16 and containers 18 shown in FIGURE 1, (2) the
support
structures 100 shown in FIGURE 7, and (3) the trays 148 shown in FIGURE 1 1.
The embodiment of FIGURES 1 1 and 12 has a number of advantages. One advantage
is that overflow liquids will drain from an upper tray to a lower tray down
the exterior of the
end walls 152 of the trays. In this manner, if the uppermost tray becomes
clogged with
sediment or the like, liquids will flow to the next tray and continue to be
filtered by the
filtering system. It is noted that the end walls slant inwardly to ensure that
overflow liquids
are directed into the next tray. Another advantage is the addition of the
diverter 142 for
ensuring liquids are processed by the filter system 10. The embodiment of
FIGURES 1 1 and
12 has all of these advantages as well as those described above, and yet still
provides a
removable rack that enables the trays to be easily and conveniently removed
from the housing
12, thus providing access to the absorbent materials and the grates.
FIGURES 13 and 14 illustrate a ninth exemplary filter system 200 in accordance
with
the invention. The filter system 200 includes a housing 202, a pair of
removable racks 204
and an upper screen or grate 206. The filter system further includes pairs of
lower and upper
filter components 208 and 210 for use in filtering liquid flowing through the
filter system.
In a typical environment, the filter components 208 and 210 house filter
material, such as
absorbent materials 212 and/or geotextile fabrics (not shown). Alternatively,
the filter
components may be used by themselves where only a course filtering of the
liquid is required
or desirable.
As will be appreciated from the following description, the filter system 200
is
substantially the same as the filter system shown in FIGURE 7, but in which
the rack, support
structures and grates have been separated into approximate halves. The filter
system 200
is an alternative to the filter systems shown in FIGURES 1 and 7 and is
beneficial in situations
where the weight of a rack, accompanying support structures and grates, and
filter material,
makes removal of the rack difficult when performing maintenance, for instance
in situations
in which storm drain opening 20 may be quite large.
The housing 202 is essentially the same as the housing 12 of FIGURES 1 and 7,
but
includes a partition or wall 214 that splits the housing into approximate
halves, forming filter
chambers 216 out of the previous single filter chamber 26. Each filter chamber
has a top
inlet 217 adjacent the outer grating 24 of the storm drain, and
~~~ i 4??~!~
-13-
a bottom outlet 218 for discharging liquids into the storm drain system. In
addition, the
housing 202 includes a pair of flanges 220 (only one of which is shown) that
extend
outwardly from the partition 214. The reference numerals for the remaining
features are the
same as in FIGURE 1.
The flanges 220, in conjunction with flanges 34, provide support for the racks
204.
Each rack 204 is shaped similarly to rack 14, although racks 204 may be of a
different size
from rack 14. Each rack includes two formed, generally U-shaped side members
222, each
including a pair of legs 224. The side members are coupled together by a
plurality of cross
members 226. The racks 204 are dimensioned slightly smaller than the inner
walls of the
housing (including the partition), such that each rack will fit into either of
the filter chambers
216, with the legs resting on inwardly-extending flanges 34 and 220 of the
housing. A top
pair of cross members 226a and 226b extend across the width of each rack to
provide
handles to allow the racks to be lifted from the housing. The remaining cross
members are
positioned in pairs on opposite sides of the rack to span between
corresponding legs of the
side members to provide support for the ends of the lower and upper filter
components 208
and 210. In this manner, the filter components are held essentially parallel
to the top of the
housing 202.
The lower filter components 208 are similar to the support structures 100 of
FIGURE
7. The upper filter components 210 are also similar to the support structures
100 of FIGURE
7, each including four sides 232, and a pair of side rails 234 (only one
shown) on two sides
for supporting a grate 236. However, the upper filter components 210
preferably do not
include an upper grate.
In using the filter system 200, the lower filter components are filled with
filter
material, if desired, and placed on the racks 204. If desired, additional
filter material, e.g.,
absorbent materials 212, is placed on the grates 236 of the each upper filter
component 210,
which are then placed into the racks 204. The racks 204 (including the filter
components)
are then placed into a housing that has been pre-positioned in a storm drain
or the like.
Thereafter, the upper grate 206 is placed on top of the racks. The upper grate
206 extends
across the entire length of the housing, and may or may not contain filter
material, such as
the material that has been placed into the upper filter components 210. A
unitary upper grate
is used instead of using individual grates because a single perforate surface
helps to spread
liquid flowing into the filter system evenly across the length of the filter
system and thus aids
liquid filtration.
In FIGURE 14, a diverter 238 has been added to the filter system 200. The
advantages of using a diverter are described in regard to FIGURE 1 1 and
_14_ I.HL ~ 4yt..~ ~
accompanying text. In addition to the features described therein, the diverter
238 includes
a plurality of bristles 240 that extend upwardly from one or more sides of the
diverter. The
bristles are designed to protrude thorough the outer grating of a storm drain
system in an
effort to catch leaves and other large debris before they enter the filter
system. To
accommodate the bristles 240, a pair of slits 242 have been cut into the outer
grating 24.
It is noted that the configuration of some gratings will enable the bristles
to extend up and
beyond the surface of the grating without modification to the grating. The
bristles decrease
the likelihood of clogging, thereby simplifying maintenance of the filter
system.
In the embodiment shown in FIGURE 14 there are bristles mounted on only two of
the
sides. The bristles are preferably mounted on those sides that receive the
majority of the
liquid entering the filter system. For example, if the filter system is
mounted on a hill or an
incline, the bristles on positioned along the upper slope.
FIGURES 15 and 16 illustrate a filter system 250 that is an alternate
embodiment of
the filter system 130 shown in FIGURE 10. More particularly, in some
applications it is
advantageous to add one or more additional filtering layers to the filter
system 130. The
embodiment shown in FIGURES 15 and 16 allows multiple layers to be
implemented, without
the added weight and expense of a housing and rack system.
The filter system 250 includes a first support structure 251 that is similar
and retains
the same component numbers as the support structure 132 in FIGURE 10. However,
the first
support structure also includes a pair of upwardly and outwardly projecting
side rails 252 that
extend at least part of the length of the support structure 251 along an outer
portion of the
sides 136. The filter system also includes a second support structure 254 that
is be
suspended beneath the support structure 251 to provide additional filtering.
The second support structure 254 includes a pair of end walls 256 that, in
conjunction
with a pair of sides 258, provide support for an upper and lower grate 260 and
262. In a
manner similar to the support structure 132, a pair of clips (not shown) hold
the upper grate
260 in place. Each side 258 has a bracket 264 that extends above the support
structure and
that includes a inward flange 266. The inward flanges 266 cooperate with the
side rails 252
of the first support structure 251 to hold the second support structure 254.
This is
accomplished by sliding the brackets onto the rails, as shown in FIGURE 16. It
will be
appreciated that additional levels of support structures could be added.
_15_
The filter system of FIGURES 15 and 16 provides multi-level filtering without
the need
for a separate housing. The filter system 250 can be constructed from less
material than the
prior art, making it lighter and less expensive while still allowing
relatively easy access to the
filter material contained therein. Hurdles, not shown, may be added to the
upper support
structure 251 to facilitate removal of the filter system 250, for instance for
maintenance.
Also, additional support structures may be utilized by depending from support
structure 254
in the same manner in which such support structure 254 depends from support
structure
251.
While the preferred embodiment of the invention has been illustrated and
described,
it will be appreciated that various changes can be made therein without
departing from the
spirit and scope of the invention. For example, an additional embodiment
includes a reservoir
for storing samples of liquid flowing through the filter system which may be
used to
determine the composition of liquids entering a storm drain or being
discharged by a
manufacturing operation. More particularly, a small pan or other container may
be attached
to one or more of the grates depicted in the filter systems of FIGURES 1-16 to
collect liquid.
