AU2005200335B2 - Filter in the form of a roll and the method of making the same - Google Patents

Description

- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: Thomas E. Pank Actual Inventor: Thomas E. Pank Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: FILTER IN THE FORM OF A ROLL AND THE METHOD OF MAKING THE SAME The following statement is a full description of this invention, including the best method of performing it known to me: File: 44793AUP00 - la FILTER IN THE FORM OF A ROLL AND THE METHOD OF MAKING THE SAME 5 RELATED CASE I hereby claim that benefit of my prior copending Provisional Application S.N. 60/543,942, filed February 12, 2004. 10 BACKGROUND OF THE INVENTION Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. U.S. Patents 5,746,911 and 6,264,835, both titled "Apparatus for separating a 15 heavy fluid from a light fluid" teach physical separators that accomplish a great deal and are an important factor in environmental protection. However, they do not remove dissolved contaminants: nor do they remove sediment particles in the fine silt and clay size range. Filtration is a proven method of removing dissolved and very fine impurities 20 from a fluid. The most commonly used filter in the stormwater industry is a depth filter. A depth filter uses a media (sand, for example) that the fluid must pass through. The removal is achieve by a combination of two mechanisms: transport and attachment. In a sand filter, the individual grains obstruct the flow of the water, forcing the fluid to take a more tortuous path through the filter. The fluid, along with the impurities to be 25 removed, is in contact with the individual grains of sand or other filter media. Bringing the contaminants into contact with the filter media is the first stage - the contaminants are transported into contact with the filter media. In order to remove the pollutants from the fluid, the media must have some way of capturing and retaining the contaminant. This - 2 can be accomplished in a number of ways, first chemical bonding on reactive media to simple sedimentation in the interstices between the media components. When designed carefully, media filtration is capable of removing large pollutant loads from influent fluid 5 streams. The selection of filter media can depend on many factors, including the type of contaminants targeted for removal, the desired flow rates through the filter, the cost and weight of the media, etc. While filtration is a proven technology in fields like 10 wastewater and drinking water treatment and industrial processes, it is relatively new in the field of stormwater treatment. One of the challenges of stormwater management is dealing with the highly variable runoff flow rates that result from storms. In stormwater applications, treatment devices are subjected to 15 widely varying flow rates, from very slow trickles to the runoff resulting from torrential downpours. To accommodate these variations, many stormwater treatment devices are designed with an internal by-pass. The internal by-pass allows flows in excess of the intended treatment capacity to pass through the unit untreated, 20 while continuing to treat flows within the intended range. This is a viable technology because of the "first flush" effect in stormwater runoff. During the beginning of a storm event, a "flush" of contaminants is carried off of a site with the first bit of runoff. This flush includes the pollutants that have collected on 25 that site since the last storm, and comprises the majority of the pollution load from each storm event. If the first flush is treated adequately, a majority of the potential contaminants will be removed -3 during that treatment, and the subsequent by-pass flows during extreme storms will not contain the same heavy pollutant loads. Filters that clean fluids, namely gasses and liquids are well known. Filters for cleaning runoff water are well known but are not only expensive to 5 manufacture but require expensive maintenance. Filters made by rolling a strip of fabric into a spiral coil having several laps are well known, see U.S. Patent 5,160,039 to Colburn and U.S. Patent 4,861,465 to Augustyniak. U.S. Patent 6,099,729 to Cella teaches a filter having a hollow cylinder with a 10 single lap of a pleated filtering element passing around the cylinder. The pleated element has several layers of flexible material. SUMMARY OF THE INVENTION It is an object of the present invention to overcome or ameliorate at least one of 15 the disadvantages of the prior art, or to provide a useful alternative. One object of a preferred form of the invention is to provide a filter that will clean both liquids and gasses. Another object of a preferred form of the invention is to reduce the cost of the filter and its maintenance. 20 Still another object of a preferred form of the invention is to provide a simple, yet very effective, filter for runoff water that has a low initial cost as well as low maintenance costs. According to a first aspect, the invention provides a method of making a filter for filtering runoff water comprising: 25 providing at least first, second and third layers of flexible material, the second and third of which layers include a filtering media; forming said layers, along with at least one drain layer into a filter element by passing said layers, including said drain layer, around a center line for 360 degrees to form a lap and further passing said layers and drain layer at least part way around said 30 lap so that said layers overlap said lap thereby providing the filter with an input side capable of receiving runoff water to be filtered and further providing the filter with an output side; - 3a providing said first layer with an input edge, at said input side, for receiving said runoff water to be filtered and also providing said first layer with two faces further providing said second layer with a first face adjacent to and forming a water transmitting relationship with one of said faces of said first layer, and providing said third layer with 5 a first face adjacent to and forming a water transmitting relationship with said other said face of said first layer, so that all of the runoff water received by said first layer passes through said filtering media in said second and third layers, and without any of the runoff water in said first layer passing directly from said first layer out of, or to, said output side; 10 providing each of said second and third layers with a second face adjacent to and forming a runoff water passageway to said drain layer so that all of the runoff water passing through said filtering media in said second and third layers will enter at least one drain layer; providing a conduit for feeding the runoff water to be filtered to said input edge of 15 said first layer; providing an output path for filtered runoff water received by said drain; said step of forming said layers, along with at least one drain layer into a filter element including providing a drain in the form of an elongated strip having at least four edges two of which edges being relatively long as compared to the other two of said four 20 edges; and forming one of said relatively long edges to be an outlet edge, so that filtered runoff water then flows to said output edge of said strip; and positioning said output edge as part of said output side. Unless the context clearly requires otherwise, throughout the description and the 25 claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". According to a second aspect, the invention provides apparatus for filtering runoff water comprising: 30 first, second and third adjacent layers of flexible material, the first layer including an input edge, the second and third layers including a filtering media that will remove contaminants in the fluid passing through said media to at least partially clean the runoff water passing through said media; - 3b a drain comprising one or more layers; said layers forming a filter, and said layers and said drain passing around a center line for 360 degrees to form a lap and further passing around said center line so that said layers overlap said lap whereby said filter has an input side for receiving the runoff 5 water to be filtered and an output side for discharging the filtered fluid; said first layer having two runoff water permeable faces; said second layer having two runoff water permeable faces, one of which is contiguous with one of said two faces of said first layer; said third layer having two runoff water permeable faces one of which is 10 contiguous with the other one of said two faces of said first layer; the other face of said second layer and the other face of said third layer comprising means for feeding filtered water to said drain, so that all of the runoff water entering said input edge of said first layer passes through said media of said second or third layers and then enters said drain without any of the runoff water in said first layer flowing directly 15 from said first layer to and out of said output side; and said drain discharging the filtered fluid; said drain comprising an elongated strip having at least four edges two of which edges being relatively long as compared to the other two edges, one of said relatively long edges being an output edge and is part of and located at said output side, said strip 20 being fed by the fluid that has passed through one of said second or third layers, such water then flowing to and being discharged by said output edge of said strip. According to a third aspect, the invention provides apparatus for filtering runoff water, comprising: first and second layers of filtering material passing around a center line for 360 25 degrees to form a lap and further passing around said center line so that said layers overlap said lap to form a spiral; said apparatus having an input side and an output side; means for receiving, at said input side, the runoff water to be filtered, said means then sending all of said runoff water received to a location between said first and second 30 layers and then said means sending all of said runoff water received from said location through said first and second layers; and means for receiving all of the water that passes through said first and second layers and discharging that water from said output side in a cylindrical shape.

- 3c The invention not only provides a new filter but also a new method of making the filter. Basically, the invention comprises providing two or more strips of flexible material (including a filtering media), stacking the strips and wrapping the contiguous 5 strips around a center line to provide a filtering element wherein at least part of the wrapped -4 strips overlaps the first lap. In its broadest form the amount of overlap may be small, for example 100, however two laps (7200), three laps (10800), or preferably about ten to fifteen laps may be employed. 5 The fluid (liquid and/or gasses) to be filtered is preferably fed to the filter in a direction parallel to said center line although it is within the scope of the broader aspects of the invention to pass the fluid through the roll in any suitable way and/or direction. 10 In the preferred form of the invention there are three strips which are stacked and wrapped into *a roll. When the strips have been wrapped and the fluid is fed to them it enters the first of the three strips. The second of the three strips is a filtering media and the third strip is a drain for discharging the fluid. from the 15 filter. The first strip not only receives the incoming fluid but redirects the fluid to pass the fluid through said filtering media to said drain. To achieve the aforesaid redirecting function the first strip is open to receive fluid at its input end but closed to such flow at 20 its other end. As a result, the water is redirected from a vertical incoming flow to a flow that has a horizontal component. The drain is closed to the fluid at the input side of the filter but open at the output side of the filter. The foregoing wrapped filter may be fed by a reservoir the 25 bottom of which is the input side of the filter. The reservoir may have a by-pass outlet to discharge- the water when the incoming water has a very large rate of flow.

-5 While, the invention is shown in the context of a filter for runoff water, the broader aspects of the invention teach how to make and use the filter in any context in which filters may be used. BRIEF DESCRIPTION OF THE DRAWINGS 5 Figure 1 is a plan view of the unrolled layered filter. Figure 2 is an elevation view of the unrolled layer filter, taken along line 2-2 as indicated in Figure 1. Figure 3 is a plan view of the rolled filter cartridge. Figure 4 is a cross section of the assembled filter taken 10 along line 4-4 in Figure 3. Figure 5 is a cross section of the layered filter, in its pre-wrapped stage. Figure 6 is a plan view of the invention. Figure 7 is a cross section of the preferred form of the 15 invention taken along line 7-7 in Figure 6. Figure 8 is a cross section of a modified form of the invention. Figure 9 is a plan view of the unrolled layered filter of Figure 8. 20 Figure 10 is a cross section of a single lap of the layered filter of Figure 8.

DETAILED DESCRIPTION OF THE PREFERRED FORM OF THE INVENTION The complete invention comprises a filter cartridge that is placed in a housing. Contaminated fluid enters the housing and 5 pools on the top of the filter cartridge. The fluid may be contaminated with solid particles, undesirable gases, dissolved dheimicals, or other pollutants. From the top of the filter cartridge, the contaminated fluid enters the cartridge by flowing downward, flows horizontally through the filter media, and then 10 flows downward out of the cartridge itself. The filter housing contains the inlet and outlet means that convey the contaminated fluid to and the treated fluid away from the invention. The method of constructing the invention is also a part of this application. The filter cartridge is constructed by rolling a 15 layered filter around a center line. Figure 1 shows a plan view and Figure 2 shows an elevation view of the unrolled layered filter, with the top 1 and bottom 2 indicated. The layered filter is significantly longer than it is wide, and is flexible enough to be rolled around itself. The filter is constructed by taking a free 20 end 3 of the unrolled filter and wrapping that end around the center line 2-2 indicated in Figure 1. The unrolled filter must be long enough for the free end 3 to make more than one lap around the center line, and may be longer (up to many laps) to provide additional filtration capacity. The resulting cartridge is then 25 oriented so that the top 1 and bottom 2 are in the correct positions. A plan view of the partially constructed filter cartridge is shown in Figure 3. Outer walls 4 are affixed to the rolled filter cartridge to provide storage chamber 5. The seams 6 -7 between the rolled layers may also be scaled to prevent the fluid from flowing between the layers instead of through the filter media. Figure 4 shows a cross section of the completed filter cartridge, taken along line 2-2 as indicated in Figure 2. During 5 operation, each "lap" around the center line functions in the same way. Figure 5 is a cross section of the layers before they are wrapped. The cross section is thin relative to its length and width so that it can be rolled. It is shown in Figure 5 vertically oriented, in the same orientation it has in the complete invention. 10 Each "lap" consists of three layers: an inlet layer 7, the filter media 8, and an outlet layer 9. The inlet layer is open at its upper end and allows water to enter the filter through openings 10. The center layer contains the filter media 8. The third layer, the outlet layer 9, has openings 12 at the bottom to allow the treated 15 fluid to flow out of the filter unit. The completed filter cartridge is housed in another structure, as shown in Figure 6. Figure 6 is a plan view of the entire invention. Inlet means 13 penetrates through the wall 14 of the main structure 15 and through the outer wall 4 of the complete 20 filter cartridge 16. Inlet means 13 has a discharge point that allows the influent fluid flow onto the top of the filter cartridge 16. The inlet means 13 is in communication with contaminated fluid storage chamber 5, which is in communication with cartridge inlet layer 7 through opening 10. In the preferred form of the invention, 25 the contaminated fluid storage chamber 5 has a single influent flowpath (through inlet means 13) and a single outlet pathway (cartridge inlet layer 7 through opening 10). Outlet means 17 penetrates the outer wall of the main structure 15. The outlet means is in communication with the outlet chamber 18 of the main structure, which is in communication with the outlet layer 9 of the filter cartridge through openings 12. 5 In a typical filter for filtering runoff water: (a) the strips 7 and 9 are made of polypropylene cloth have a thickness of 0.3 inches and a width of 30 inches; and (b) the filter strip 8 is made of high grade geotextile fabric, has a thickness of 0.3 inches and a width of 30 inches. 10 Each input cloth 9 has one side edge that will be at the bottom end of the filter of Figure 4. Each such edge is sealed with silicon. The upper side edge will be open and free to receive water from space 5 of Figure 7. Each drain layer 7 has a first side edge, that will be at the top end of the filter and sealed closed with 15 silicon so that water may not flow through that edge. The lower side edge of each drain layer is open so that the water in drain layer 7 may flow out of the bottom end of the filter. After the elements 7, 8, and 9 have been assembled as shown in Figure 5, they form a flexible strip about one to two inches thick and many feet 20 long. The resulting strip is now wrapped around a central post, or center line, so as to form a spiral. For some applications the filter media 8 may preferably be sand or some other layer of small particles, in which case permeable layers 11 may be used. The permeable layers 11 are optional and are 25 preferably used when it is necessary to do so in order to hold the filter media in place. They may be made of porous cloth.

- 9 OPERATION OF THE PREFERRED FORM OF THE INVENTION Contaminated fluid enters the filter through inlet means 13. (Fig. 7). The fluid flows from inlet means 13 and into contaminated fluid storage chamber 5. Contaminated fluid storage chamber 5 is in 5 communication with the cartridge inlet layer 7 in each lap of the rolled filter cartridge. The contaminated fluid flows from the contaminated fluid storage chamber 5 into cartridge inlet layer 7 through openings 10. In the cartridge inlet layer 7, the fluid makes a 90 degree turn and flows through the filter media 8. The 10 fluid flows through the filter media 8, where the contaminants are removed by the media, and into the fluid outlet layer 9. In the fluid outlet layer 9, the fluid once again makes a 90 degree turn and flows downward, out of the filter cartridge through openings 12 and into the outlet chamber 18 of the main structure 15. The 15 treated fluid then flows to the outlet means 17 and exits the invention through said outlet means. If the flow into the invention through inlet means 13 exceeds the flow capacity of the filter media, the fluid is backed up in contaminated fluid storage chamber 5. When the head in this chamber 20 rises, whether that rise is due to rising fluid surface elevation or rising pressure, the fluid within the filter cartridge 16 is driven through the filter media more quickly. The increased flow rate serves to relieve the rising head upstream from the invention.

- 10 DETAILED DESCRIPTION OF A MODIFIED FORM OF THE INVENTION The modified form of the invention comprises an alternate layering of the rolled filter. The filter cartridge is again 5 constructed by rolling a layered filter around a center line. Figure 9 shows a plan view and Figure 10 shows an elevation view of the unrolled layered filter, with the top 101 and bottom 102 indicated. The layered filter is significantly longer than it is wide, and is flexible enough to be rolled around itself. The filter 10 is constructed by taking a free end 103 of the unrolled filter and wrapping that end around the line 11-11 indicated in Figure 10. The unrolled filter must be long enough for the free end 103 to make at least more than one lap around the center line, and may be longer to provide additional filtration capacity. The resulting cartridge is 15 then oriented so that the top 101 and bottom 102 are in the correct positions. Figure 8 shows a cross section of the unrolled layered filter, taken along line 11-11 as indicated in Figure 10. The cross section is thin relative to its length and height so that it can be 20 rolled. It is shown in Figure 8 vertically oriented, with the same orientation it has in the complete invention. Each "lap" consists of three components: a center inlet layer 107, the U-shaped filter media layer 108, and the outlet drains 109. The center inlet layer is open at the top, and allows water to enter the filter through 25 openings 110. The U-shaped media layer contains the filter media 108, and surrounds the inlet layer 107. Filter media 108 can be selected specifically for the anticipated pollutants to be removed - 11 from the influent fluid, and can be sand, fabric, or other material. If filter media 108 is of indeterminate shape (sand, for example), it is held in place by permeable barrier 111, through which the water can flow at a faster rate than it can flow through the filter 5 media. The third component, the outlet drains 109, are separated from the filter media by permeable barrier 111 (when present). Outlet drains 109 have openings 112 at the bottom to allow the treated fluid to flow out of the filter unit. In the modified form of the invention, the completed filter 10 unit is placed in the invention housing in the same manner as it is in the preferred form. OPERATION OF THE MODIFIED FORM OF THE INVENTION The operation of the first modified form of the invention is very similar to that of the preferred form. Figure 6 and Figure 7 15 show the layout of the first modified form of the invention as well as the preferred form. Contaminated fluid enters the invention through inlet means 213. The fluid flows from inlet means 213 and into contaminated fluid storage chamber 205. From contaminated fluid storage chamber 205, the influent fluid enters the filter 20 cartridge 216. The contaminated fluid flows from the contaminated fluid storage chamber 205 into cartridge inlet layer 107 through openings 110. In the cartridge inlet layer 107, the fluid makes a 90 degree turn in either direction and flows through permeable barrier 111 25 (when present) and into the filter media 108. The fluid flows through the filter media 108, where the contaminants are: removed by the media, passes through permeable barrier 111 when present, and - 12 into one of two of the fluid outlet drains 109. In the fluid outlet drain 109, the fluid once again makes a 90 degree turn and flows downward, out of the filter cartridge through openings 112. The treated fluid flow from the filter cartridge 216 into the 5 outlet chamber 218 of the main structure 215. The treated fluid then flows to the outlet means 217 and exits the invention through said outlet means.

Claims (18)

1. A method of making a filter for filtering runoff water comprising: providing at least first, second and third layers of flexible material, the second and 5 third of which layers include a filtering media; forming said layers, along with at least one drain layer into a filter element by passing said layers, including said drain layer, around a center line for 360 degrees to form a lap and further passing said layers and drain layer at least part way around said lap so that said layers overlap said lap thereby providing the filter with an input side 10 capable of receiving runoff water to be filtered and further providing the filter with an output side; providing said first layer with an input edge, at said input side, for receiving said runoff water to be filtered and also providing said first layer with two faces further providing said second layer with a first face adjacent to and forming a water transmitting 15 relationship with one of said faces of said first layer, and providing said third layer with a first face adjacent to and forming a water transmitting relationship with said other said face of said first layer, so that all of the runoff water received by said first layer passes through said filtering media in said second and third layers, and without any of the runoff water in said first layer passing directly from said first layer out of, or to, said 20 output side; providing each of said second and third layers with a second face adjacent to and forming a runoff water passageway to said drain layer so that all of the runoff water passing through said filtering media in said second and third layers will enter at least one drain layer; 25 providing a conduit for feeding the runoff water to be filtered to said input edge of said first layer; providing an output path for filtered runoff water received by said drain; said step of forming said layers, along with at least one drain layer into a filter element including providing a drain in the form of an elongated strip having at least four 30 edges two of which edges being relatively long as compared to the other two of said four edges; and forming one of said relatively long edges to be an outlet edge, so that filtered runoff water then flows to said output edge of said strip; and - 14 positioning said output edge as part of said output side.

2. Apparatus for filtering runoff water comprising: first, second and third adjacent layers of flexible material, the first layer including 5 an input edge, the second and third layers including a filtering media that will remove contaminants in the fluid passing through said media to at least partially clean the runoff water passing through said media; a drain comprising one or more layers; said layers forming a filter, and said layers and said drain passing around a center 10 line for 360 degrees to form a lap and further passing around said center line so that said layers overlap said lap whereby said filter has an input side for receiving the runoff water to be filtered and an output side for discharging the filtered fluid; said first layer having two runoff water permeable faces; said second layer having two runoff water permeable faces, one of which is 15 contiguous with one of said two faces of said first layer; said third layer having two runoff water permeable faces one of which is contiguous with the other one of said two faces of said first layer; the other face of said second layer and the other face of said third layer comprising means for feeding filtered water to said drain, so that all of the runoff water entering said 20 input edge of said first layer passes through said media of said second or third layers and then enters said drain without any of the runoff water in said first layer flowing directly from said first layer to and out of said output side; and said drain discharging the filtered fluid; said drain comprising an elongated strip having at least four edges two of which 25 edges being relatively long as compared to the other two edges, one of said relatively long edges being an output edge and is part of and located at said output side, said strip being fed by the fluid that has passed through one of said second or third layers, such water then flowing to and being discharged by said output edge of said strip. 30

3. The method of filtering runoff water as defined in claim 1, comprising: said step which provides a drain comprises providing two separate drains and feeding them from the second and third layers respectively. - 15

4. Apparatus for filtering runoff water as defined in claim 2, in which said drain comprises two drains one fed by the filtered output of said second layer and the other fed by the filtered output of said third layer.

5 5. Apparatus for filtering runoff water as defined in claim 2, in which said filtering media is sand.

6. Apparatus for filtering runoff water as defined in claim 2, in which said drain comprises a layer of cloth. 10

7. Apparatus for filtering water as defined in claim 6, in which each said layer of cloth is a layer of polypropylene cloth.

8. Apparatus for filtering runoff water as defined in claim 2, in which there is a 15 reserviour holding said runoff water, said input side facing, and contiguous with, said runoff water in said reservoir.

9. A method of making a filter as defined in claim 1, in which said step of passing said layers around a center line includes positioning a drain layer as the outermost one of 20 said layers that are passed around said center line.

10. Apparatus for filtering runoff water as defined in claim 2, in which the outermost one of said layers being a drain layer. 25

11. A method of making a filter as defined in claim 1, in which said step of passing said layers around a center line includes positioning a drain as the innermost one of the layers that are passed around said center line.

12. Apparatus for filtering runoff water as defined in claim 2, in which said layers are 30 in the shape of a spiral with the innermost layer of the spiral being a drain layer.

13. A method of making a filter for filtering runoff water as defined in claim 1, wherein: said step of forming layers comprising providing a drain layer as the innermost 35 layer, providing a filtering layer contiguous to said innermost layer, providing an input - 16 layer contiguous to said filtering layer, and providing a second filtering layer contiguous to said input layer.

14. Apparatus for filtering runoff water as defined in claim 2, wherein: 5 said drain layer being the innermost layer, said second layer being contiguous with said innermost layer, said input layer being contiguous with said second layer, and said third layer outside of and contiguous with said first layer.

15. The method of filtering runoff water as defined in claim 1, comprising: 10 positioning said drain layer as the innermost one of said layers; positioning said second layer contiguous to said drain layer and as the second layer from the center line; positioning said first layer contiguous with said second layer and with said second layer and drain layer between said first layer and the center line; 15 said third layer being contiguous with said first layer and as the fourth layer from the center line.

16. Apparatus for filtering runoff water, comprising: first and second layers of filtering material passing around a center line for 360 20 degrees to form a lap and further passing around said center line so that said layers overlap said lap to form a spiral; said apparatus having an input side and an output side; means for receiving, at said input side, the runoff water to be filtered, said means then sending all of said runoff water received to a location between said first and second 25 layers and then said means sending all of said runoff water received from said location through said first and second layers; and means for receiving all of the water that passes through said first and second layers and discharging that water from said output side in a cylindrical shape. 30

17. A method of making a filter for filtering runoff water substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. -17

18. Apparatus for filtering runoff water substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. 5