U.S. patent application number 11/807645 was filed with the patent office on 2008-12-04 for inlet filter.
Invention is credited to Andrew P. Swan.
Application Number | 20080296211 11/807645 |
Document ID | / |
Family ID | 40086918 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080296211 |
Kind Code |
A1 |
Swan; Andrew P. |
December 4, 2008 |
Inlet filter
Abstract
An inlet filter for use with stormwater drains and roof drains.
The filter is formed of a mat of natural or synthetic fiber
material with netting bonded on one side. A convenient method for
attaching the filter to a drain using cable ties or adhesive is
provided.
Inventors: |
Swan; Andrew P.; (Michigan
City, IN) |
Correspondence
Address: |
RYNDAK & SURI LLP
200 W. MADISON STREET, SUITE 2100
CHICAGO
IL
60606
US
|
Family ID: |
40086918 |
Appl. No.: |
11/807645 |
Filed: |
May 30, 2007 |
Current U.S.
Class: |
210/163 |
Current CPC
Class: |
E03F 5/0404 20130101;
E03F 1/00 20130101 |
Class at
Publication: |
210/163 |
International
Class: |
E03F 5/06 20060101
E03F005/06 |
Claims
1. An inlet filter for a drain inlet having a grate, comprising: a
fiber mat; and a plurality of flexible locking connectors for
insertion through the mat to secure the mat to the grate.
2. The filter of claim 1 wherein the fiber is a natural fiber.
3. The filter of claim 2 wherein the natural fiber is coir.
4. The filter of claim 1 wherein the fiber is a synthetic
fiber.
5. The filter of claim 1 wherein the fiber mat has a density of
about 4.0 OSF.
6. The filter of claim 1 wherein the fiber mat is about 1.5 inches
thick.
7. The filter of claim 1 wherein the fiber mat is bonded on one
side to a mesh.
8. The filter of claim 1 wherein the flexible locking connector is
a cable tie.
9. The filter of claim 1 wherein the inlet is a stormwater
drain.
10. The filter of claim 1 wherein the inlet is a roof drain.
11. A method for reducing the amount of sediment which enters a
drain, comprising placing a filter as described in claim 1 over the
drain inlet and securing the filter to the grate by inserting the
flexible locking connectors through the mat, passing each connector
around a bar of the grate and back through the mat and locking each
connector,
12. A method for installing a filter on a drain inlet having a
grate, comprising: providing a fiber mat of a size and shape to
cover and slightly overlap the inlet; placing the mat over the
inlet; and securing the mat to the drain.
13. The method of claim 12 wherein securing the mat comprises
attaching the mat to the grates by flexible locking connectors
passed through the mat and around bars of the grate.
14. The method of claim 13 wherein the flexible locking connectors
are cable ties.
15. The method of claim 12 wherein the fiber is selected from the
group consisting of natural fiber, synthetic fiber, and blended
natural and synthetic fiber.
16. The method of claim 12 wherein the fiber mat has a density of
about 4.0 OSF.
17. The method of claim 12 wherein the fiber mat is about 1.5
inches thick.
18. The method of claim 12 wherein the fiber mat is bonded on one
side to a mesh.
19. The method of claim 12 wherein the inlet is a stormwater
drain.
20. The method of claim 12 wherein the inlet is a roof drain and
securing the mat comprises applying adhesive around the perimeter
of the roof drain and the perimeter of one side of the mat to
adhere the mat to the roof material around the perimeter of the
roof drain.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to inlet filters,
and in particular, inlet filters for use on stormwater drains and
roof drains, and a method for installing an inlet filter on a
drain.
BACKGROUND OF THE INVENTION
[0002] Stormwater drains are provided in streets, roads, parking
lots and the like to permit water runoff to be directed into
underground catch basins and drainage pipes. The drains are
provided with a grate to screen out larger debris and to prevent
persons and vehicles from falling into the drains. The grates may
be of various configurations, such as flat, roll curb, vertical or
beehive.
[0003] It is desirable to keep silt and sediment from entering a
drain to avoid clogging of catch basins and drainage pipes. This is
especially true on a construction site, where large quantities of
silt, sediment and other debris may be present. In the construction
of streets, highways, residential housing developments and shopping
centers and other commercial developments, it is typical to first
lay out the streets. Then, the stormwater drainage system is
installed. This system includes underground drainage pipes,
culverts, catch basins and drop inlets that connect the underground
parts of the system to a finished street-level drain inlet, such as
a roll curb inlet with grate. As construction continues,
considerable sediment and debris may be generated, which will be
pushed by rain, wind and gravity towards the drains. Building
codes, municipal regulations and environmental rules often require
that such debris be prevented from entering the storm drain system.
Simultaneously, the drains must be kept open and functional to
permit rain water to drain.
[0004] Roof drains are provided in flat roofs, such as those on
large commercial buildings, to drain rainwater. These drains are
typically fitted with flat or beehive grates. Like stormwater
drains in streets, roof drains need to be kept clear of sediment
and debris so that water drains freely and does not accumulate on
the roof where it can cause damage.
[0005] Various filters have been used to protect the inlets of the
stormwater systems and roof drains, but all suffer from certain
disadvantages. One disadvantage with many existing filters is that
the grate must be removed from the inlet to install the filter.
Other filters are complex and expensive. Those types which fit
below the grate inside the drain are difficult to clean or
replace.
[0006] There is a need for an inlet filter to protect inlets of
stormwater and roof drains and prevent sediment from entering the
inlet while allowing water to pass through substantially unimpeded.
There is also a need for an inlet filter which can be quickly and
easily attached to and removed from a drain without removing the
drain grate. There is also a need for an inexpensive filter that
can be cut to fit in the field and that will fit inlets of various
shapes and sizes, such as flat, roll curb, vertical and beehive
inlets. There is also a need for an inlet filter that can be
readily cleaned without removal from the drain. There is a need for
a filter that is resistant to degradation from exposure to
ultraviolet (UV) radiation in sunlight. Further, there is a need
for a stormwater drain inlet filter that will not be dislodged or
damaged by vehicular traffic and will not present a hazard to
pedestrians.
SUMMARY OF THE INVENTION
[0007] In accordance with the present invention, an inlet filter
for a drain inlet having a grate includes a fiber mat and a
plurality of flexible locking connectors for insertion through the
mat to secure the mat to the grate.
[0008] In accordance with a preferred embodiment of the invention,
the fiber mat is a natural fiber such as coir fiber, with a
thickness and density selected to achieve an acceptable combination
of sediment control and water flow, and the flexible connector is a
Nylon cable tie.
[0009] In another aspect, the invention provides a method for
reducing the amount of sediment which enters a drain, comprising
placing a filter over the drain inlet and securing the filter to
the grate by inserting flexible locking connectors through the mat,
passing each connector around a bar of the grate and back through
the mat and locking each connector.
[0010] In another aspect, the invention provides a method for
installing a filter on a drain inlet that includes providing a mat
of a size and shape to cover and slightly overlap the inlet, and
attaching the mat to the grates by flexible locking connectors
passed through the mat and around bars of the grate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a cross-sectional view of an inlet filter in
accordance with the invention.
[0012] FIG. 2 is an illustration of an inlet filter for
installation on a flat street grate.
[0013] FIG. 3 is an illustration of an inlet filter for
installation on a curb grate.
[0014] FIG. 4 is an illustration of an inlet filter for
installation on a beehive grate.
[0015] FIG. 5 is an illustration of an inlet filter for
installation on a beehive grate with an exposed overflow
section.
[0016] FIG. 6 illustrates a method of installing an inlet filter on
a grate.
DETAILED DESCRIPTION OF THE INVENTION
[0017] As shown in FIG. 1, the body of filter 2 is a mat 4 of fiber
material with a netting or mesh 6 bonded to the fiber material of
mat 4 on one side to provide structural integrity. Preferably, mat
4 is made of a natural fiber such as coir fiber, and mesh 6 is made
of fiberglass. However, mat 4 may also be made of a suitable
synthetic fiber or a blend of natural and synthetic fibers. The
fibers may be bonded together with a binder such as latex. Mesh 6
may be made of another suitable material. The openings in mesh 6
may be generally square and about 3/16 inch on a side, or another
suitable shape and size.
[0018] In a preferred embodiment, mat 4 is about 11/2 inches thick
and has a density of about 4.0 OSF (ounces per square foot). This
thickness and density of coir fiber have been found to provide a
desirable combination of sediment control and water flow. More
specifically, a coir fiber mat with these characteristics has been
shown to provide a filtering efficiency of 59.1% while maintaining
a flow rate of 150 liters/minute when tested with sand sieved
through a No. 10 sieve, thus complying with industry standards for
silt filtering efficiency and flow rates (e.g., ASTM D 5141). The
preferred coir material has also been found to exhibit good UV
resistance, tensile properties and smolder resistance.
[0019] The inlet filter of the invention may be used on flat street
grates as shown in FIG. 2, roll curb inlets as shown in FIG. 3, and
beehive-type grates as shown in FIGS. 4 and 5. The filter may be
used not only on street drains but also on roof drains of the type
typically found on flat roofs of commercial buildings, which may
have a flat or beehive grate. Filters may be provided pre-cut to
size for standard size grates, e.g., 27.times.30 inches.
Alternately, the filter material may be provided in rolls or sheets
and cut to size on site to fit any size or shape drain grate.
[0020] Inlet filter 2 is easily attached to the inlet grate with
flexible locking connectors 8, i.e., cable ties or "zip" ties. A
cable tie consists of a sturdy Nylon tape with an integrated gear
rack, and on one end a ratchet within a small open case. Black
cable ties are typically used for outdoor applications, as the
ultraviolet component of sunlight will degrade clear nylon. Once
the pointed tip of the cable tie has been pulled through the case
and past the ratchet, it is prevented from being pulled back; the
resulting loop may only be pulled tighter.
[0021] The method for installing inlet filter 2 will now be
described with reference to FIG. 6. First, sediment, debris, ice
and snow are removed from the inlet grate surface and the immediate
surrounding area, using, e.g., a broom as shown in FIG. 6A. If the
filter is not pre-cut, it is now cut to size with a knife or
shears. Fit is verified by placing filter 2 over the grate 10 to
ensure that filter 2 extends at least one inch beyond all sides of
a street grate, or the front and both curb ends of a curb grate.
This overlap ensures that the inlet is completely protected, and
also slows water flow and starts filtering sediment and debris
before water drops into the inlet. Water flow slows as it flows
longitudinally through filter 2, allowing sediment to drop, and
filtration as water passes through filter 2 transversely further
reduces sediment load. Filter is positioned on grate 10 with net 6
side down. In the case of a curb grate, filter 2 is positioned
flush to the back edge and extending beyond the grate opening on
the front and both sides.
[0022] Once positioned, filter 2 is lifted slightly as shown in
FIG. 6B so the installer can see the first grate bar 12 from the
edge of the grate cover. The installer takes a cable tie 8, pushes
its free, pointed end 8a down through mat 4, and loops tie 8 under
grate bar 12 as shown in FIG. 6C. The installer inserts pointed end
8a of tie 8 about 2 inches away from the first tie penetration and
pushes it back up through mat 4. Normally, this may be done by hand
without tools; however, the installer may also make a small hole in
mat 4 with a screwdriver, awl or pointed stick to facilitate
insertion of tie 8. Pointed end 8a of tie 8 is inserted into the
receiving end 8b just enough to hold the ends loosely. This process
is repeated until all of ties 8 are loosely installed as shown in
FIG. 6D. Ties 8 are left loose until all of ties 8 are looped
through mat 4 around the grate bars. Preferably, eight ties are
used for a flat street grate or beehive grate, and seven are used
for a curb grate. Of course, the number of ties can be varied
depending on the size of the grate. Ties 8 are preferably
positioned around the perimeter of the grate as shown in FIGS.
2-4.
[0023] After all of ties 8 are attached, filter 2 is repositioned
as needed to completely cover and properly overlap grate 10. Free
ends 8a of each of ties 8 are the pulled hand tight to securely
anchor filter 2 to grate 10. Excess loose end portions 8a of ties 8
may be cut off leaving an approximately one inch tail.
[0024] Some situations, and some municipal regulations, may require
an exposed overflow to accommodate extreme flow conditions.
Exposing the emergency overflow section of the drain allows
unfiltered water flow when the water depth exceeds the height of
the filter. In this case, an opening 14 is cut in filter 2 with a
knife or shears to expose the upper portion of the overflow section
of the drain as shown in FIG. 5.
[0025] Maintenance of the installed filter is simple and
convenient. The filter may be cleaned without removing it from the
grate, even if ponded water surrounds the inlet. The top and sides
of filter 2 are swept with a broom to remove sediment and debris
which accumulate after a rain event. In the case of standing water
at the inlet, sweeping away built-up debris allows water to drain
through the filter.
[0026] When construction work is completed or the filter is
otherwise no longer needed, or the filter needs to be replaced, it
may be easily removed without removing the grate from the inlet,
simply by cutting ties 8.
[0027] In the case of a roof drain, the filter may be installed
using roofing adhesive instead of cable ties. In this case,
suitable roofing adhesive is applied to the perimeter of the mesh
side of the filter to adhere it to the roof about the perimeter of
the drain.
[0028] The foregoing is intended to represent one embodiment of the
present invention and is not intended to limit in any way the scope
of the invention. Additional modifications and enhancements to the
invention may be apparent to those of skill in the art.
* * * * *