AU2008221239A1 - Separating solid or particulate matter from a fluid flow, in particular, a stormwater flow, and further with an overflow bypass - Google Patents

Description

WO 2008/104030 PCT/AU2008/000262 SEPARATING SOLID OR PARTICULATE MATTER FROM A FLUID FLOW, IN PARTICULAR, A STORMWATER FLOW, AND FURTHER WITH AN OVERFLOW BYPASS. Field of the Invention This invention relates to a separator with an overflow bypass, and more particularly, but not exclusively, to a separator for stormwater with an overflow bypass. Background of the Invention It is known to provide a separator for separating solid or particulate matter from stormwater. However, the applicant has identified that existing separators are not suitable for use in separating stormwater prior to passing into an underground water storage tank structure as they either have no bypass capability for dealing with overflow, or they have a bypass capability which mixes unfiltered stormwater with filtered stormwater. Underground water storage tank structures, particularly of the kind formed of stacked plastic modules the same or similar to those shown in Australian Patent No. 724,847, are typically not able to be readily cleaned of pollutants which may be contained in unfiltered stormwater. Examples of the present invention seek to provide an improved separator for filtering water passing into a storage container. Summary of the Invention In accordance with one aspect of the present invention, there is provided an apparatus for separating solid or particulate matter from a flowing fluid, the apparatus including: an inlet for allowing unfiltered fluid to enter the apparatus; filter means for separating material from the unfiltered fluid; a first outlet for delivering filtered fluid from the apparatus; and a second outlet for delivering unfiltered fluid from the apparatus when the level of fluid in the apparatus exceeds a predetermined level.

WO 2008/104030 PCT/AU2008/000262 -2 Preferably, the apparatus further includes a diverter, wherein an upper level of the diverter defines the predetermined level. More preferably, the diverter is arranged such that unfiltered fluid is diverted by the diverter to the filter means to exit the first outlet 5 when the level of unfiltered fluid at the diverter is below the upper level, and wherein unfiltered fluid is allowed to flow over the diverter to bypass the filter means and to exit the second outlet when the level of the unfiltered fluid at the diverter is above the upper level. 10 In a preferred example, the filter means includes a separation chamber into which, in use of the apparatus, the unfiltered fluid is introduced by the diverter to establish a circular flow of fluid within the separation chamber such that solids or particulate matter of a predetermined size drop into a sump below the separation chamber. Preferably, a wall of the separation chamber includes a separation screen having a plurality of openings of a 15 predetermined size for preventing solid or particulate matter larger than that size from passing outwardly through the separation screen so as to filter the fluid. Preferably, the apparatus is provided with a first flow sensor for sensing flow through the first outlet. More preferably, the apparatus is provided with a second flow 20 sensor for sensing flow through the second outlet. In one example, the apparatus activates an indicator in response to the second flow sensor sensing flow through the second outlet so as to alert an operator that the apparatus may require maintenance. An output of the first flow sensor may be used to determine cause of flow through the second outlet. 25 In accordance with another aspect of the present invention, there is provided an apparatus for separating solid or particulate matter from a flowing fluid, the apparatus including: an inlet for allowing unfiltered fluid to enter the apparatus; a separation chamber into which, in use of the apparatus, the unfiltered fluid is 30 introduced by a diverter to establish a circular flow of fluid within the separation chamber such that solids or particulate matter of a predetermined size drop into a sump below the separation chamber, a wall of the separation chamber including a separation screen having a plurality of openings of a predetermined size for preventing solid or particulate matter WO 2008/104030 PCT/AU2008/000262 -3 larger than that size from passing outwardly through the separation screen so as to filter the fluid; an outer chamber arranged about the separation chamber and being accessible to fluid in the separation chamber only via the openings in the separation screen; 5 a first outlet for allowing flow of fluid from the outer chamber to exit the apparatus; and a second outlet, separate from the first outlet, for allowing unfiltered fluid to flow directly from the inlet to bypass the separation chamber and to exit the apparatus, wherein the diverter diverts unfiltered fluid into the separation chamber when a 10 level of the fluid at the diverter is at or below a top level of the diverter so as to follow a filtering path via the openings in the separation screen and through the outer chamber to the first outlet, and wherein the diverter allows unfiltered fluid to flow over the diverter when the level of the fluid at the diverter is above the top level so as to follow a non filtering path, separate to the filtering path, in which the unfiltered fluid bypasses the 15 separation chamber and exits the apparatus through the second outlet. In accordance with another aspect of the present invention, there is provided an apparatus for separating solid or particulate matter from stormwater flowing to a water storage container, the apparatus including: 20 an inlet adapted for fluid communication with a stormwater drainage conduit so as to, in use, allow unfiltered stormwater to enter the apparatus from the stormwater drainage conduit; a separation chamber into which, in use of the apparatus, the unfiltered stormwater is introduced by a diverter to the separation chamber, a wall of the separation chamber 25 including a screen having a plurality of openings of a predetermined size for preventing solid or particulate matter larger than that size from passing through the screen so as to filter the stormwater; a receiving chamber arranged on an opposite side of the screen relative to the separation chamber and being accessible to stormwater in the separation chamber only via 30 the openings in the screen; a first outlet adapted for fluid communication with the water storage container so as to, in use, allow flow of stormwater from the receiving chamber to exit the apparatus to the water storage container; and WO 2008/104030 PCT/AU2008/000262 -4 a second outlet, separate from the first outlet, for allowing unfiltered stormwater to flow directly from the inlet to bypass the separation chamber and to exit the apparatus, wherein the diverter diverts unfiltered stormwater into the separation chamber when a level of the stormwater at the diverter is at or below a top level of the diverter so as 5 to follow a filtering path via the openings in the screen and through the receiving chamber to the first outlet, and wherein the diverter allows unfiltered stormwater to flow over the diverter when the level of the stormwater at the diverter is above the top level so as to follow a non-filtering path, separate to the filtering path, in which the unfiltered stormwater bypasses the separation chamber and exits the apparatus through the second 10 outlet. Preferably, the second outlet is in fluid communication with the stormwater drainage conduit, at a location downstream of the inlet, for allowing unfiltered stormwater to exit the apparatus to the stormwater drainage conduit. 15 Preferably, the apparatus is provided with a first flow sensor for sensing flow along the filtering path. More preferably, the apparatus is provided with a second flow sensor for sensing flow along the non-filtering path. In one example, the apparatus activates an indicator in response to the second flow sensor sensing flow along the non-filtering path so 20 as to alert an operator that the apparatus may require maintenance. An output of the first flow sensor may be used to determine cause of flow through along the non-filtering path. In accordance with yet another aspect of the present invention, there is provided an apparatus for separating solid or particulate matter from stormwater supplied by a 25 stormwater drainage conduit, including a diverter which diverts unfiltered stormwater from the conduit into a separation chamber when a level of the stormwater at the diverter is at or below a top level of the diverter so as to follow a filtering path via openings in a separation screen to a storage container via a first outlet, and which diverter allows unfiltered stormwater to flow over the diverter when the level of the stormwater at the diverter is 30 above the top level so as to follow a non-filtering path, separate to the filtering path, in which the unfiltered stormwater bypasses the separation chamber and is returned to the stormwater drainage conduit via a second outlet.

WO 2008/104030 PCT/AU2008/000262 -5 Brief Description of the Drawings The invention is described by way of non-limiting example only, with reference to the accompanying drawings in which: 5 Figure 1 is a cut-away view of a prior inline separator unit; Figure 2 is a cut-away view of another prior inline separator unit; 10 Figure 3 is a top perspective cut-away view of the inline separator of Figure 2, sectioned in a plane transverse to the direction of stormwater flow; Figure 4 is a top cross-sectional view of the separator shown in Figures 2 and 3; 15 Figure 5 is a side cross-sectional view of the separator shown in Figures 2 to 4; Figure 6 is a top cross-sectional view of a separator in accordance with an example of the present invention; 20 Figure 7 is a side cross-sectional view of the separator of Figure 6, the section being taken along the line "A" shown in Figure 6; Figure 8 is a top cross-sectional view of the separator shown in Figures 6 and 7; 25 Figure 9 is a side view of a removable screen of the separator shown in Figures 6 to 8; and Figure 10 is side cross-sectional view of the separator shown in Figures 6 to 9, the section being taken along line "B" shown in Figure 8. 30 WO 2008/104030 PCT/AU2008/000262 -6 Detailed Description With reference to Figure 1 there is shown a previous inline separator unit 10 which is adapted for placement in a storm drain within a single manhole. The unit combines 5 treatment and bypass capabilities to remove both fine and suspended solids along with oil, grease, rubbish and debris. The unit 10 includes a channelling weir 12 which collects flow for entrance into a separation chamber 14. A natural vortex in the separation chamber 14 separates suspended and fine sediments to the centre of the chamber 14 for eventual settling in a sump 16 located below the diversion chamber 14. A separation screen 18 10 which forms a wall of the separation chamber 14 is designed so as to avoid blockage. Flow of stormwater through the separation screen 18 is discharged from the separator 10 via an outlet 20, after flowing beneath an oil baffle 22 which retains oil within the unit 10. In the event of flows in excess of 50 cubic feet per second, flow is able to bypass the separation chamber so as to flow directly to the outlet 20. 15 The unit 10 reportedly removes 80 percent of total suspending solids as well as 100 percent of floatables and neutrally buoyant material, plus oil and grease. Due to the non blocking design of the screen 18 and the generally non-mechanical operation of the unit 10, it is a low maintenance treatment option requiring cleaning once annually to maintain 20 its successful and efficient operation. Figures 2 to 5 show another form of previous inline separator unit 24 which uses a similar induced vortex flow to separate gross pollutants, organics, soot/sediment and oils from stormwater. The unit 24 is formed of a polymer which makes it light and easy to use 25 in source control applications and small catchments. The unit has an inlet 26, a diverter 28, a separation chamber 30, an outer chamber 32 which surrounds the separation chamber 30, a sump 34, and a single outlet 36. Operation of the separator unit 24 is shown diagrammatically in Figure 2 in which arrows are used to indicate flow of fluid through the unit 24. 30 More specifically, flow of unfiltered stormwater through the inlet 26 is diverted by the diverter 28 into the separation chamber 30. The diverter 28 is curved so as to induce a clockwise vortex flow within the separation chamber 30, which causes separation of WO 2008/104030 PCT/AU2008/000262 -7 suspended and fine sediments to the centre of the chamber 30 for eventual settling in the sump 34. Stormwater filtered through the screen 38 of the separation chamber 30 flows into the outer chamber 32 to form an anticlockwise flow about the separation chamber 30 and upwardly to exit the unit 24 through the single outlet 36. 5 However, the applicant has identified that neither unit 10 nor unit 24 is suitable for use in separating stormwater prior to passing into an underground water storage tank structure of the type formed of stacked plastic modules the same or similar to those disclosed in Australian Patent No. 724;847. As it is difficult to clean an underground 10 water storage tank structure of this kind, the applicant has identified the need for a separator which will not bypass unfiltered stormwater into the tank structure in the event of overflow, whether that overflow is caused as a result of blockage of the screen of the separator or simply excessive flow of stormwater at the inlet of the separator. 15 The separator apparatus 40 shown in Figures 6 to 10 is adapted to enable bypass of a filter element of the separator in the event of overflow while ensuring that only filtered stormwater is outlet into the water storage container. The apparatus 40 includes an inlet 42, a diverter 44, a separation chamber 46 20 having a screen 48, a receiving chamber 50, a first outlet 52, and a second outlet 54. The inlet 42 is adapted for fluid communication with a stormwater drainage conduit so as to, in use, allow unfiltered stormwater to enter the apparatus 40 from the stormwater drainage conduit. In use of the apparatus 40, the unfiltered stormwater is introduced by the 25 diverter 44 to the separation chamber 46. As a result of the diverter 44 leading tangentially into a wall 56 of the separation chamber 46, the unfiltered fluid introduced by the diverter 44 is established in a circular flow within the separation chamber 46. Owing to the circular flow of the stormwater, solids or particulate matter of a predetermined size drop into a sump 58 below the separation chamber 46, as shown in Figure 7 by arrow 60, in a manner 30 similar to that show in Figure 2. The screen 48 forms at least part of the wall 56 of the separation chamber 46 and has a plurality of openings 62 of a predetermined size for preventing solid or particulate WO 2008/104030 PCT/AU2008/000262 -.8 matter larger than that size from passing outwardly through the separation screen 48 to the outer receiving chamber 50. Owing to geometry of the openings 62 and/or the circular flow of the stormwater, solid or particulate matter smaller than the size of the openings 62 may also be prevented from passing outwardly through the separation screen 48 to the 5 outer receiving chamber 50. In this way, the stormwater which reaches the outer receiving chamber 50 is filtered, as the receiving chamber 50 is accessible to the stormwater in the separation chamber 46 only via the apertures 62 in the separation screen 48. The first outlet 52 is adapted for fluid communication with the water storage 10 container so as to, in use, allow flow of stormwater from the receiving chamber 50 to exit the apparatus 40 to the water storage container. The first outlet 52 is accessible to stormwater at the inlet 42 via only the apertures 62 in the screen 48, thus ensuring that all stormwater exiting to the water storage container has been filtered. More particularly, this may be ensured by providing a full height wall 68 around an aperture 70 formed in a floor 15 surface 72 around the top of the separation screen 48, through which aperture 70 filtered water is able to flow from the receiving chamber 50 to the first outlet 52. Specifically, in a direction perpendicular to the page in Figure 6 the full height wall 68 extends between the floor surface 72 and a ceiling 74 of the apparatus 40. The full height wall 68 encloses the aperture 70 and the first outlet 52 by extending in a first portion 75 which runs from one 20 edge adjoining a separating wall 76 between the first outlet 52 and the second outlet 54, to an opposite edge which adjoins an arcuate second portion 78 running above and in line with a section of the separation screen 48. The second portion 78 adjoins a third portion 80 which extends adjacent one edge of the aperture 70 to one side of the first outlet 52. Accordingly, the aperture 70 and the first outlet 52 are enclosed to prevent them from 25 receiving unfiltered water. In one alternative, the second portion 78 may extend in a clockwise direction (as seen in Figure 6) to a frontward full height wall 82, which configuration may be relied upon to enclose the aperture 70 and the first outlet 52 from unfiltered water. 30 The second outlet 54 is separate to the first outlet 52, and is arranged to allow unfiltered stormwater to flow directly from the inlet 42 to bypass the separation chamber WO 2008/104030 PCT/AU2008/000262 -9 46 and to exit the apparatus 40, so as to be returned to the stormwater drainage conduit at a location downstream of the inlet 42. The diverter 44 is arranged in a weir-like configuration to divert unfiltered 5 stormwater from the inlet 42 into the separation chamber 46 when a level of the stormwater at the diverter 44 is at or below a top level of the diverter 44, so as to follow a filtering path 64 via the openings 62 in the screen 48 and through the receiving chamber 50 to the first outlet 52 via aperture 70. In the event of overflow, which may be caused by either excessive flow of stormwater at the inlet 42 and/or by blockage of the screen 48, the 10 diverter 44 allows unfiltered stormwater to flow over the diverter 44 when the level of the stormwater at the diverter 44 is above the top level so as to follow a non-filtering path 66, which is separate to the filtering path 64, and in which the unfiltered stormwater bypasses the separation chamber 46 and exits the apparatus 40 through the second outlet 54. 15 The apparatus 40 may also be provided with a flow sensor for sensing flow along the non-filtering path 66 and/or a flow sensor for sensing flow along the filtering path 64. The flow sensor(s) may be in the form of a previously known type of sensor for sensing fluid flow such as, for example, a spindle which is rotated in response to flow exerting force on fins (or the like) attached to the spindle. An indicator which may be in the form 20 of an audible or visual alarm is activated in response to flow along the non-filtering path 66 being sensed so as to alert an operator that the apparatus 40 may require maintenance. In this way, the operator is able to inspect the apparatus 40, and to clean the screen 48 and/or the sump 58, to restore effective operation of the apparatus 40. 25 An output of the flow sensor for sensing flow along the filtering path 64 may be used to determine cause of flow along the non-filtering path 66. For example, flow along both the filtering path 64 and the non-filtering path 66 may indicate the cause of flow along the non-filtering path as being excessive flow at the inlet 26, whereas flow along only the non-filtering path may indicate blockage of the screen 38. 30 The above apparatus 40 has been described by way of example only and modifications are possible within the scope of the invention. For example, although the WO 2008/104030 PCT/AU2008/000262 -10 apparatus 40 is described as being used in a stormwater system, it will be understood by those skilled in the art that the apparatus may also be used to separate other fluids. The reference in this specification to any prior publication (or information derived 5 from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 10 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (17)

1. An apparatus for separating solid or particulate matter from a flowing fluid, the apparatus including: 5 an inlet for allowing unfiltered fluid to enter the apparatus; filter means for separating material from the unfiltered fluid; a first outlet for delivering filtered fluid from the apparatus; and a second outlet for delivering unfiltered fluid from the apparatus when the level of fluid in the apparatus exceeds a predetermined level. 10

2. An apparatus as claimed in claim 1, the apparatus further including a diverter, wherein an upper level of the diverter defines the predetermined level.

3. An apparatus as claimed in claim 2, wherein the diverter is arranged such that 15 unfiltered fluid is diverted by the diverter to the filter means to exit the first outlet when the level of unfiltered fluid at the diverter is below the upper level, and wherein unfiltered fluid is allowed to flow over the diverter to bypass the filter means and to exit the second outlet when the level of the unfiltered fluid at the diverter is above the upper level. 20

4. An apparatus as claimed in claim 2 or claim 3, wherein the filter means includes a separation chamber into which, in use of the apparatus, the unfiltered fluid is introduced by the diverter to establish a circular flow of fluid within the separation chamber such that solids or particulate matter of a predetermined size drop into a 25 sump below the separation chamber.

5. An apparatus as claimed in claim 4, wherein a wall of the separation chamber includes a separation screen having a plurality of openings of a predetermined size for preventing solid or particulate matter larger than that size from passing 30 outwardly through the separation screen so as to filter the fluid.

6. An apparatus as claimed in any one of claims 1 to 5, wherein the apparatus is provided with a first flow sensor for sensing flow through the first outlet. WO 2008/104030 PCT/AU2008/000262 - 12

7. An apparatus as claimed in any one of claims I to 6, wherein the apparatus is provided with a second flow sensor for sensing flow through the second outlet. 5

8. An apparatus as claimed in claim 7, wherein the apparatus activates an indicator in response to the second flow sensor sensing flow through the second outlet so as to alert an operator that the apparatus may require maintenance. 10

9. An apparatus as claimed in claim 8, when dependent on claim 6, wherein an output of the first flow sensor is used to determine cause of flow through the second outlet.

10. An apparatus for separating solid or particulate matter from a flowing fluid, the 15 apparatus including: an inlet for allowing unfiltered fluid to enter the apparatus; a separation chamber into which, in use of the apparatus, the unfiltered fluid is introduced by a diverter to establish a circular flow of fluid within the separation chamber such that solids or particulate matter of a predetermined size drop into a 20 sump below the separation chamber, a wall of the separation chamber including a separation screen having a plurality of openings of a predetermined size for preventing solid or particulate matter larger than that size from passing outwardly through the separation screen so as to filter the fluid; an outer chamber arranged about the separation chamber and being 25 accessible to fluid in the separation chamber only via the openings in the separation screen; a first outlet for allowing flow of fluid from the outer chamber to exit the apparatus; and a second outlet, separate from the first outlet, for allowing unfiltered fluid to 30 flow directly from the inlet to bypass the separation chamber and to exit the apparatus, wherein the diverter diverts unfiltered fluid into the separation chamber when a level of the fluid at the diverter is at or below a top level of the diverter so WO 2008/104030 PCT/AU2008/000262 - 13 as to follow a filtering path via the openings in the separation screen and through the outer chamber to the first outlet, and wherein the diverter allows unfiltered fluid to flow over the diverter when the level of the fluid at the diverter is above the top level so as to follow a non-filtering path, separate to the filtering path, in which the 5 unfiltered fluid bypasses the separation chamber and exits the apparatus through the second outlet.

11. An apparatus for separating solid or particulate matter from stormwater flowing to a water storage container, the apparatus including: 10 an inlet adapted for fluid communication with a stormwater drainage conduit so as to, in use, allow unfiltered stormwater to enter the apparatus from the stormwater drainage conduit; a separation chamber into which, in use of the apparatus, the unfiltered stormwater is introduced by a diverter to the separation chamber, a wall of the 15 separation chamber including a screen having a plurality of openings of a predetermined size for preventing solid or particulate matter larger than that size from passing through the screen so as to filter the stormwater; a receiving chamber arranged on an opposite side of the screen relative to the separation chamber and being accessible to stormwater in the separation 20 chamber only via the openings in the screen; a first outlet adapted for fluid communication with the water storage container so as to, in use, allow flow of stormwater from the receiving chamber to exit the apparatus to the water storage container; and a second outlet, separate from the first outlet, for allowing unfiltered 25 stormwater to flow directly from the inlet to bypass the separation chamber and to exit the apparatus, wherein the diverter diverts unfiltered stormwater into the separation chamber when a level of the stormwater at the diverter is at or below a top level of the diverter so as to follow a filtering path via the openings in the screen and 30 through the receiving chamber to the first outlet, and wherein the diverter allows unfiltered stormwater to flow over the diverter when the level of the stormwater at the diverter is above the top level so as to follow a non-filtering path, separate to WO 2008/104030 PCT/AU2008/000262 - 14 the filtering path, in which the unfiltered stormwater bypasses the separation chamber and exits the apparatus through the second outlet.

12. An apparatus as claimed in claim 9, wherein the second outlet is in fluid 5 communication with the stormwater drainage conduit, at a location downstream of the inlet, for allowing unfiltered stormwater to exit the apparatus to the stormwater drainage conduit.

13. An apparatus as claimed in any one of claims 10 to 12, wherein the apparatus is 10 provided with a first flow sensor for sensing flow along the filtering path.

14. An apparatus as claimed in any one of claims 10 to 13, wherein the apparatus is provided with a second flow sensor for sensing flow along the non-filtering path.

15 15. An apparatus as claimed in claim 14, wherein the apparatus activates an indicator in response to the second flow sensor sensing flow along the non-filtering path so as to alert an operator that the apparatus may require maintenance.

16. An apparatus as claimed in claim 15, when dependent on claim 13, wherein an 20 output of the first flow sensor is used to determine cause of flow along the non filtering path.

17. An apparatus for separating solid or particulate matter from stormwater supplied by a stormwater drainage conduit, including a diverter which diverts unfiltered 25 stormwater from the conduit into a separation chamber when a level of the stormwater at the diverter is at or below a top level of the diverter so as to follow a filtering path via openings in a separation screen to a storage container via a first outlet, and which diverter allows unfiltered stormwater to flow over the diverter when the level of the stormwater at the diverter is above the top level so as to 30 follow a non-filtering path, separate to the filtering path, in which the unfiltered stormwater bypasses the separation chamber and is returned to the stormwater drainage conduit via a second outlet.