Settling device for rainwater

Abstract

A settling device (10) for a rainwater drainage system (100) comprises a lamella settling device comprising a first end (11), a second end (12) opposite the first end and a longitudinal axis (L) extending between the first end (11) and second end (12). The lamella settling device comprises a lamella inlet portion (20) comprising one or more fluid inlets (21a, 21b). The lamella settling device (10) also comprises a lamella outlet portion (30) comprising, for each fluid inlet (21a, 21b), one or more respective fluid outlets (31a, 31b) spaced apart from the respective fluid inlet along the longitudinal axis towards the second end of the lamella settling device. The lamella settling device (10) further comprises a plurality of settling elements (40) which each comprise one or more lamella surfaces (41) inclined with respect to the longitudinal axis, the plurality of settling elements spaced apart along the longitudinal axis to define one or more intervening spaces (50) fluidically connecting the lamella inlet portion (20) and the lamella outlet portion (30). In use, when fluid passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end.

Description

[0001] SETTLING DEVICE FOR RAINWATER

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to settling devices for removing particular matter from a liquid, and in particular settling devices for rainwater drainage systems, and methods relating to said settling devices.

[0004] BACKGROUND

[0005] Due to increasing regulation with respect to infiltration of stormwater and release to surface waters, particularly in urban environments, there is an ever-increasing need for rainwater filtration devices with improved filtration effectiveness. Such filtration devices often must be retrofitted to existing systems. Additionally, some stormwater drainage systems may be restricted in terms of available space.

[0006] There is therefore a need for devices which minimise footprint (that is, space occupied in the system) and / or filters or similar devices for removing particulate matter which optimise filtration efficiency or effectiveness.

[0007] SUMMARY OF THE INVENTION

[0008] According to one aspect, there is provided a settling device for a rainwater drainage system. The settling device comprises a lamella settling device comprising a first end, a second end opposite the first end and a longitudinal axis extending between the first end and second end. The lamella settling device comprises a lamella inlet portion comprising one or more fluid inlets. The lamella settling device also comprises a lamella outlet portion comprising, for each fluid inlet, one or more respective fluid outlets spaced apart from the respective fluid inlet along the longitudinal axis towards the second end of the lamella settling device. The lamella settling device further comprises a plurality of settling elements. The plurality of settling elements each comprise one or more lamella surfaces inclined with respect to the longitudinal axis, the plurality of settling elements spaced apart along the longitudinal axis to define one or more intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion. In use, when fluid passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end.

[0009] According to a second aspect, there is provided a method of manufacturing a settling device for a rainwater drainage system. The method comprises providing a lamella settling device, including providing a plurality of settling elements, wherein the lamella settling device comprises a first end, a second end opposite the first end and a longitudinal axis extending between the first end and second end. The lamella settling device comprises a lamella inlet portion comprising one or more fluid inlets. The lamella settling device also comprises a lamella outlet portion comprising, for each fluid inlet, one or more respective fluid outlets spaced apart from the respective fluid inlet along the longitudinal axis towards the second end of the lamella settling device. The lamella settling device further comprises a plurality of settling elements. The plurality of settling elements each comprise one or more lamella surfaces inclined with respect to the longitudinal axis, the plurality of settling elements spaced apart along the longitudinal axis to define one or more intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion. In use, when fluid passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end.

[0010] According to a third aspect, there is provided a method for separating particulate matter from rainwater using the settling device according to the first aspect. The method comprises the steps of: providing a vortex flow of rainwater at the lamella inlet portion; and flowing the rainwater through the plurality of settling elements and out of the lamella outlet portion. When the rainwater passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end to provide filtered rainwater at the outlet portion.

[0011] According to a fourth aspect, there is provided a method for cleaning a rainwater drainage system comprising a settling device according to the first aspect, the lamella settling device being an insert configured to be placed inside a rainwater drainage system, the settling device being provided in an inspection chamber, the method comprising the step of removing the lamella settling device from the inspection chamber and cleaning the settling device and / or the inspection chamber.

[0012] According to a fifth aspect, there is provided a method for cleaning a rainwater drainage system comprising a settling device according to the first aspect, the settling device comprising a tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device. The method comprises the step of extending a cleaning tool through the tubular element and cleaning the second side of the settling device using the cleaning tool.

[0013] BRIEF DESCRIPTION OF THE DRAWINGS To enable better understanding of the present disclosure, and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying schematic drawings, in which:

[0014] Fig. 1A shows a schematic side view of a settling device for a rainwater drainage system according to one or more embodiments as shown and described herein.

[0015] Fig. IB shows a schematic cross-sectional side view of the settling device shown in Fig. 1A, taken along the line B-B shown in Fig. 1C.

[0016] Fig. 1C shows a schematic top view of the settling device shown in Figs. lA and IB.

[0017] Fig. 2 shows a schematic cross-sectional side view of a settling device according to one or more embodiments as shown and described herein.

[0018] Fig. 3 shows a schematic side view of a settling device according to one or more embodiments as shown and described herein.

[0019] Fig. 4 shows a schematic side view of a settling device according to one or more embodiments as shown and described herein.

[0020] Fig. 5 shows a schematic side view of a settling device according to one or more embodiments as shown and described herein.

[0021] Fig. 6A shows a schematic cutaway perspective view of a settling device according to one or more embodiments as shown and described herein.

[0022] Fig. 6B shows a cross-sectional side view of the settling device shown in Fig. 6A, taken along the line B-B shown in Fig. 6C.

[0023] Fig. 6C shows a top view of the settling device shown in Figs. 6A and 6B.

[0024] Fig. 7A shows a side view of a settling device according to one or more embodiments as shown and described herein.

[0025] Fig. 7B shows a schematic cutaway perspective view of the settling device shown in Fig. 7A.

[0026] Fig. 7C shows a schematic cutaway perspective view of the settling device shown in Figs. 7A and 7B in an inspection chamber.

[0027] Fig. 7D shows a schematic top view of the inspection chamber and settling device shown in Fig. 7C.

[0028] Fig. 8 shows a perspective view of a collection tray for a settling device according to one or more embodiments as shown and described herein. Fig. 9 shows a perspective view of a baffle device for a settling device according to one or more embodiments as shown and described herein.

[0029] Fig. 10 shows a schematic view of a rainwater drainage system including a settling device according to one or more embodiments as shown and described herein.

[0030] Fig. 11 A shows a schematic cross-sectional side view of a settling device according to one or more embodiments as shown and described herein.

[0031] Fig. 11B shows a schematic perspective view of the settling device shown in Fig. 11A.

[0032] Fig. 11C shows a schematic side view of the settling device shown in Fig. 11A.

[0033] DETAILED DESCRIPTION

[0034] As used herein, the term “inlet” may refer to any point or region where fluid may enter an element comprising the inlet. The inlet may take any suitable shape or size. Similarly, the term “outlet” may refer to any point or region where fluid may exit an element comprising the outlet.

[0035] As used herein, the term “lamella settling device” may refer to any element for separating particulate matter from a liquid, wherein the settling device comprises a plurality of spaced apart inclined lamella surfaces (relative to the vertical axis, in use) onto which the particulate matter may settle. The inclined surfaces may be inclined at any suitable angle, and different parts of a given inclined surface may be inclined at different angles to the vertical. The inclined surfaces may take any form. For example, the inclined surfaces may include planar regions, curved regions, corrugated regions or any other surface shape. The plurality of inclined surfaces may be identical to one another or different in form / shape to one another.

[0036] As used herein, the term “settling element” may refer to any element comprising one or more surfaces onto which particulate matter may settle, such as one or more inclined lamella surfaces.

[0037] As used herein, the term “vortex flow” may refer to movement of a fluid in a circular path about a longitudinal axis.

[0038] As used herein, the term “insert” may refer to a first component which is configured to be inserted into second, separate, component, wherein the first component and second component are non-unitary separate bodies. Put differently, the first component and second component have a disassembled condition in which the components are separated, and an assembled condition in which the first component is inserted into the second component.

[0039] As used herein, the term “inspection chamber” may refer to a chamber of a stormwater drainage system which is accessible, for example by opening a cover or door of the drainage system, to inspect a part of the drainage system. The inspection chamber may be underground. An example of an inspection chamber is a manhole, although it will be appreciated that the term “inspection chamber” includes any other chambers in a stormwater drainage system which is accessible to a user, such as gullies.

[0040] As used herein, the term “conical” may refer to the shape of a cone. The cone may be circular, oval or an irregular cone. The term “at least partially conical” may refer to an element having a region which corresponds to a shape of at least part of a cone, but does not necessarily correspond exactly to a cone - for example the element may omit certain regions of the cone to which it corresponds.

[0041] As used herein, the term “frustoconical” may refer to the shape of a frustum of a cone. The cone may be circular, oval or irregular cone.

[0042] As used herein, the term “pyramidical” may refer to the shape of a pyramid. The base of the pyramid may be regular (e.g. square, triangular, pentagonal or the like), or irregular (e.g. any irregular polygon). The term “at least partially pyramidical” may refer to an element having a region which corresponds to a shape of at least part of a pyramid (regular or irregular), but does not necessarily correspond exactly to a pyramid - for example, the element may omit certain regions of the pyramid to which it partially corresponds.

[0043] As used herein, the term “frustopyramidical” may refer to the shape of a frustum of a pyramid. The base of the pyramid may be regular (e.g. square, triangular, pentagonal or the like), or irregular (e.g. any irregular polygon).

[0044] As used herein, the term “tubular element” may refer to any element which is hollow in shape and configured to fluidically connect one or more inlets of the tubular element to the one or more outlets of the tubular element. It will be appreciated that although in the illustrated embodiments the tubular elements take particular lengths and cross-sectional shapes, other lengths and cross-sectional shapes may be used without departing from the scope of the invention.

[0045] As used herein, the term “baffle” may refer to any element which is configured to inhibit vortex flow. The baffle may for example be a plate, wall or any other suitable barrier extending across a region. It will be appreciated that the baffle may be placed in any suitable configuration and shape such as planar, curved, vertical, inclined and so on.

[0046] As used herein, the term “cyclonic separation” or “hydrodynamic separation” may refer to separation of particulate matter from a liquid by the rotational effects of cyclonic motion. In particular, particles tend to separate in a direction away from the centre of the cyclonic motion due to their inertia. As used herein, the term “sedimentation” may refer to separation of particulate matter from a liquid by the gravitational effects on the particulate matter. In particular, gravity causes the particles to sink to the bottom of the liquid over time.

[0047] Fig. 1A shows a schematic side view of a settling device for a rainwater drainage system according to one or more embodiments. Fig. IB shows a schematic cross-sectional side view of the settling device shown in Fig. 1A, taken along the line B-B shown in Fig. 1C. Fig. 1C shows a schematic top view of the settling device shown in Figs. 1 A and IB. Certain reference numerals are shown in some of Figs. 1 Ato 1C and omitted in others, for brevity, although Figs. lAto 1C relate to the same embodiment.

[0048] The settling device is suitable for a rainwater drainage system, and may be provided separately to the rainwater drainage system, such as in the form of an insert. The settling device comprises a lamella settling device 10 comprising a first end 11, a second end 12 opposite the first end 11 and a longitudinal axis L extending between the first end 11 and second end 12. The lamella settling device 10 comprises a lamella inlet portion 20 and a lamella outlet portion 30. The lamella inlet portion 20 comprises one or more fluid inlets 21a, 21b. The lamella outlet portion 30 comprises, for each fluid inlet 21a, 21b, one or more respective fluid outlets 3 la, 3 lb spaced apart from the respective fluid inlet 21a, 21b along the longitudinal axis L towards the second end 12 of the lamella settling device 10. The settling device additionally comprises a plurality of settling elements 40. Each of the settling elements 40 comprise one or more lamella surfaces 41 inclined with respect to the longitudinal axis L, and are additionally spaced apart along the longitudinal axis L to define intervening spaces 50 fluidically connecting the lamella inlet portion 20 and the lamella outlet portion 30. In use, the longitudinal axis L is approximately vertical and the lamella surfaces 41 are therefore inclined relative to the vertical. As a result of the inclination of the lamella surfaces 41 relative to the vertical axis, when fluid passes through the one or more intervening spaces 50 from the lamella inlet portion 20 to the lamella outlet portion 30, particulate matter in the fluid settles on the lamella surfaces 41 as a result of gravity in a direction away from the second end 12. Additionally, the intervening spaces 50 define one or more closed-loop fluid paths F for vortex flow in the lamella settling device 10.

[0049] Advantageously, as the intervening spaces 50 allow for close-loop vortex flow, any vortex flow for fluid flowing into lamella settling device 10 is maintained and not inhibited, allowing for cyclonic separation of particulate matter to occur in the intervening spaces 50. At the same time, the effectiveness of the lamella settling device 10 further increases because the flow path of the fluid along the lamella surfaces 41 is also increased, meaning that particles with a longer settling length (i.e., lighter particles) are more likely to settle on the lamella surface 41 before reaching the outlets 31a, 31b, thus falling away down the lamella surface 41 and separated from the fluid. This creates a synergistic effect of increased filtration within the settling device due to both sedimentation along the lamella surfaces, as well as cyclonic or hydrodynamic separation.

[0050] In some embodiments, outlet portion 30 may be fluidically connected to the inlet portion 20 only via the intervening spaces 50, such that any fluid reaching the outlet portion 30 must pass through the intervening spaces 50 and along the lamella surfaces 41. This ensures the filtration occurs for all fluid reaching the outlet portion 30.

[0051] It is noted that in the embodiment shown in Figs. lAto 1C, the inlets 21 are the annular edges of the intervening spaces 50, being the location where fluid enters into the intervening spaces 50. As such, the inlets 21 extend about the entire circumference of each intervening space 50. It will be appreciated that any other suitable configuration for the inlets may be used without departing from the scope of the invention. For example, there may be provided one or more walls or struts extending longitudinally along the outer edge of the settling elements 40 such that each intervening space 50 comprises multiple inlets 31.

[0052] It is also noted that in the embodiment shown in Figs. lAto 1C, the outlet portion 30 comprises a tubular element 32 having a laterally extending portion 32a for fluidically connecting the lamella outlet portion 30 to a drainage outlet of a rainwater drainage system. It will be appreciated that in some embodiments the laterally extending portion 32a is not provided without departing from the scope of the invention. The laterally extending portion 32a may be configured to connect to the drainage outlet by any suitable connecting mechanism known in the art, such as a press-fit connection, threaded or screw-fit connection, a compression fit connection and the like. As shown in the figures, the lumen defined by laterally extending portion 32a may be substantially free of troughs, pockets or the like, where water may get trapped. Accordingly, the laterally extending portion 32a may be free from siphons for extracting water trapped in such troughs or pockets, and any other such water-extracting mechanisms.

[0053] The settling device described with reference to Figs. lAto 1C may be an insert configured to be placed inside a rainwater drainage system such as in the inspection chambers 90 described with reference to Figs. 6Ato 6C, or in the system 100 described with reference to Fig. 10.

[0054] The settling device described with reference to Figs. 1A to 1C may further comprise a flow guide upstream of the lamella inlet portion for inducing vortex flow in the settling device, such as the flow guide 60 described with reference to Figs. 6Ato 6C or the flow diverter 65 described with reference to Figs. 7A to 7D. The flow guide induces vortex fluid into the fluid before it enters the lamella settling device 10, meaning that the flow path within the lamella settling device 10 from the respective inlets 21 to the respective outlets 31 is increased. This in turn increases the amount of particulate removed from the water exiting the outlet portion 30. The settling device described with reference to Figs. lA to 1C includes a plurality of stacked nested concave settling elements 40 to form a plurality of stacked nested lamella surfaces 41. This allows for a higher density of lamella surfaces 41 for a given volume, resulting in a low footprint settling device. It will be appreciated that in other embodiments, one or more settling elements 40 may be non-nested, i.e., one or more settling elements 40 may be provided outside of the concave space of any other settling element 40.

[0055] It will be appreciated that although three settling elements 40 are shown which collectively form two intervening spaces 50, any number of settling elements 40 forming a corresponding number of intervening spaces 50 may be used. For example, 10 or more settling elements 40 may be used, which may be stacked and nested.

[0056] The settling device described with reference to Figs. 1A to 1C comprises partially conical settling elements 40, and in particular frustoconical settling elements 40. It will be appreciated that the settling elements 40 may take any suitable shape, such as at least partially pyramidical forming a plurality of at least partially conical or pyramidical lamella surfaces, such as frustopyramidical, or any other suitable shape.

[0057] In the settling device described with reference to Figs. lAto 1C, fluid inlets 21 are located at a radially outer portion of the intervening spaces 50 and the respective fluid outlets 31 are located at a radially inner portion of the intervening spaces 50. This maximises vortex flow at the inlets 21 and therefore increases the flow path of the fluid along the lamella surfaces 41, thus leading to a higher filtration rate. It will be appreciated that in other embodiments, the inlets 21 may be located at a radially inner portion of the intervening spaces 50 and the outlets 31 may be located at a radially outer portion of the intervening spaces 50.

[0058] The settling device described with reference to Figs. lAto 1C comprises an outlet portion 30 which comprises a tubular element 32 having a laterally extending portion 32a for fluidically connecting the lamella outlet portion 30 to a drainage outlet of a rainwater drainage system. The settling device may alternatively or additionally comprise a tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device, such as described with reference to Figs. 6Ato 6C and 7Ato 7D.

[0059] The lamella outlet portion 30 of the settling device described with reference to Figs. lAto 1C comprises a tubular element 32, and the settling elements 40 are located on an outer surface of the tubular element 32 extending radially outwards from the outer surface. The fluid outlets 31 include fluid ports traversing the tubular element 32 to connect the intervening spaces 50 to an interior space of the tubular element 32. However, in other embodiments the settling elements 40 may not be located on an outer surface of a tubular element. For example, the settling elements 40 may be mounted to one another by any suitable mounting structure, and further may be configured to connect directly to an outlet of an inspection chamber without an intermediate tubular element such as tubular element 32.

[0060] The settling device described with reference to Figs. 1A to 1C may further comprise one or more baffles configured to be placed beneath the first end 11 of the lamella settling device 10 for inhibiting vortex flow, such as those described with reference to Figs. 8 and 9.

[0061] The settling device described with reference to Figs. 1 Ato 1C may further comprise a collection tray configured to be placed beneath the first end 11 of the lamella settling device 10, such as the collection tray 70 described with reference to Fig. 8, such that in use, particulate matter falling from the lamella surfaces 41 as a result of gravity is collected by the collection tray.

[0062] It will be understood that the lamella surfaces 41 may be inclined relative to the longitudinal axis at any suitable angle. In preferred embodiments, at least some, and preferably all, of the lamella surfaces 41 comprise at least a sub-area which is inclined relative to the first end 11 by an angle sufficiently steep to inhibit particulate matter from settling on said lamella surfaces, and preferably an angle of 45° or less, wherein a smaller angle means a steeper incline. Angles of 45° or less lead to self-cleaning of the lamella surface 41 as particulate matter slides off the lamella surfaces 41. It will be appreciated that the exact angle at which particulate matter is prevented from settling on the lamella surfaces will depend on the exact configuration (such as shape, flow rates and flow directions). Depending on the configuration of the settling device, the threshold angle for inhibiting particulate matter from settling can be determined empirically.

[0063] It will be understood that the distance between the inlets 21 and outlets 31 may be any suitable distance. Similarly, the depth D of the intervening spaces 50 (measured in a direction perpendicular to the lamella surface 41 associated with the intervening space 50) may be any suitable depth, and an intervening space 50 may have a range of depths over its volume. In preferred embodiments, for at least one inlet 21 and respective outlet 31 for one or more intervening spaces 50, the distance between the inlet and the outlet is given by d, and the depth D of the intervening space (or, if not constant, at least some depths over the volume of the intervening space) is less than d. In more preferred embodiments, the depth D of the intervening space along the longitudinal axis is less than 0.5d, and more preferably less than 0.25d, even more preferably less than O. ld. The relatively smaller depth of the intervening space 50 provides a narrower flow path for the fluid though the intervening spaces 50, which means particulate matter entering the intervening space at the inlet 21 will enter the lamella settling device 10 closer to the lamella surface 41, This increases the likelihood that particulate matter will settle on the surfaces 41 before reaching the outlet 31, and thus be separated away, as the maximum sedimentation distance, given by D, is relatively smaller. It will be understood that the intervening spaces may be identical in shape (for example they may all have the same depth D), or they may be different (for example they may have different depths, shapes or sizes).

[0064] The settling elements 40 described with reference to Figs. lAto 1C are each singular, unitary bodies. However, in other embodiments they may comprise one or more settling element parts which may be mounted to a mounting structure, as described with reference to Figs. 7Ato 7D.

[0065] Fig. 2 shows a schematic cross-sectional side view of another settling device according to one or more embodiments. The settling device comprises a lamella settling device 10 similar to that described with reference to Figs. lA to 1C, and may comprise any of the features described with reference to Figs. lAto 1C. Reference numerals indicating corresponding features in Figs. lAto 1C are omitted for brevity. It is noted that the settling device of Fig. 2 comprises a higher number of settling elements 40 than in Figs. lA to 1C. Furthermore, the outlets 31 comprise one or more longitudinally extending slots 36, such that each slot 36 extends across multiple settling elements 40 and intervening spaces 50 and thus comprises multiple outlets 31 across multiple intervening spaces 50.

[0066] It will be appreciated that any variants or alternative embodiments disclosed herein with reference to the other figures can equally be applied to the embodiment of Fig. 2.

[0067] Fig. 3 shows a schematic side view of another settling device according to one or more embodiments The settling device comprises a lamella settling device 10 similar to that described with reference to Figs. 1A to 1C and 2, and may comprise any of the features described with reference to Figs. lAto 1C and 2. Reference numerals indicating corresponding features in Figs. lAto 1C are omitted for brevity. It is noted that the lamella settling device 10 of Fig. 3 comprises a higher number of settling elements 40 than in Figs. 1A to 1C. Furthermore, the settling elements 40 are non-identical and taper in diameter consecutively towards the first end 11. In other embodiments, the settling elements 40 are non-identical and taper consecutively towards the first end 12.

[0068] It will be appreciated that any variants or alternative embodiments disclosed herein with reference to the other figures can equally be applied to the embodiment of Fig. 3.

[0069] Fig. 4 shows a schematic side view of another settling device according to one or more embodiments The settling device comprises a lamella settling device 10 similar to that described with reference to Figs. 1A to 1C, 2 and 3, and may comprise any of the features described with reference to Figs. 1A to 1C, 2 and 3. Reference numerals indicating corresponding features in Figs. 1A to 1C are omitted for brevity. It is noted that the lamella settling device 10 of Fig. 4 comprises settling elements 40 which each have undulating or corrugated lamella surfaces, as opposed to the smooth cone-like surfaces of the settling elements 40 shown in Figs. lAto 3. It will be appreciated that the lamella surfaces 41 may take many other shapes without departing from the scope of the invention. It will be appreciated that any variants or alternative embodiments disclosed herein with reference to the other figures can equally be applied to the embodiment of Fig. 4.

[0070] Fig. 5 shows a schematic side view of another settling device according to one or more embodiments The settling device comprises a lamella settling device 10 similar to that described with reference to Figs. lAto 4, and may comprise any of the features described with reference to Figs. lAto 1C to 4. Reference numerals indicating corresponding features in Figs. 1A to 1C are omitted for brevity. It is noted that the lamella settling device 10 of Fig. 4 comprises settling elements 40 having lamella surfaces 41 inclined relative to the longitudinal axis at an angle of 30°, allowing for effective self-cleaning of the lamella surfaces 41.

[0071] It will be appreciated that any variants or alternative embodiments disclosed herein with reference to the other figures can equally be applied to the embodiment of Fig. 5.

[0072] Whilst not illustrated in Figs. 3 to 5, it will be appreciated that the illustrated settling devices comprise all of the features of the invention. Namely, the settling devices are suitable for a rainwater drainage system, and may be provided separately to the rainwater drainage system, such as in the form of an insert. The settling devices comprise a lamella settling device 10 comprising a first end, a second end opposite the first end and a longitudinal axis extending between the first end and second end. The lamella settling device 10 comprises a lamella inlet portion and a lamella outlet portion. The lamella inlet portion comprises one or more fluid inlets. The lamella outlet portion comprises, for each fluid inlet, one or more respective fluid outlets spaced apart from the respective fluid inlet along the longitudinal axis towards the second end of the lamella settling device. The settling device additionally comprises a plurality of settling elements. Each of the settling elements comprise one or more lamella surfaces inclined with respect to the longitudinal axis, and are additionally spaced apart along the longitudinal axis to define intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion. In use, the longitudinal axis is approximately vertical, and the lamella surfaces are therefore inclined relative to the vertical. As a result of the inclination of the lamella surfaces relative to the vertical, when fluid passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end. Additionally, the intervening spaces define one or more closed-loop fluid paths for vortex flow in the lamella settling device.

[0073] Fig. 6A shows a schematic cutaway perspective view of a settling device shows a schematic side view of a settling device according to one or more embodiments, in which a wall of inspection chamber 90 is partially cutaway to illustrate the interior of the inspection chamber 90. Fig. 6B shows a cross-sectional side view of the settling device shown in Fig. 6A, taken along the line B-B shown in Fig. 6C. Fig. 6C shows a top view of the settling device shown in Figs. 6Aand 6B. Certain reference numerals are shown in some of Figs. 6Ato 6C and omitted in others, for brevity, although Figs. 6Ato 6C relate to the same embodiment.

[0074] The settling device is situated in an inspection chamber 90 of a rainwater drainage system, and may be provided separately to the inspection chamber 90 rainwater drainage system, such as in the form of an insert, or may be provided with the inspection chamber 90. The settling device comprises a lamella settling device 10 comprising a first end 11, a second end 12 opposite the first end 11 and a longitudinal axis L extending between the first end 11 and second end 12. The lamella settling device 10 comprises a lamella inlet portion 20 and a lamella outlet portion 30. The lamella inlet portion 20 comprises a plurality of fluid inlets 21 (only the uppermost one is labelled in Fig. 6A, for brevity). The lamella outlet portion 30 comprises, for each fluid inlet 21, a plurality of respective fluid outlets (unlabelled for brevity) spaced apart from the respective fluid inlet 21 along the longitudinal axis L towards the second end 12 of the lamella settling device 10. The outlets comprise one or more longitudinally extending slots 36a-36c, such that each slot 36 extends across multiple settling elements 40 and intervening spaces (unlabelled for brevity) and comprises multiple outlets across multiple intervening spaces. The settling device additionally comprises a plurality of settling elements 40 (only the uppermost one is labelled in Fig. 6A, for brevity). Each of the settling elements 40 comprise one or more lamella surfaces 41 (only one labelled in Fig. 6B, for brevity) inclined with respect to the longitudinal axis L, and are additionally spaced apart along the longitudinal axis L to define the intervening spaces fluidically connecting the lamella inlet portion 20 and the lamella outlet portion 30. In use, the longitudinal axis L is approximately vertical and the lamella surfaces 41 are therefore inclined relative to the vertical. As a result of the inclination of the lamella surfaces 41 relative to the vertical, when fluid passes through the one or more intervening spaces 50 from the lamella inlet portion 20 to the lamella outlet portion 30, particulate matter in the fluid settles on the lamella surfaces 41 as a result of gravity in a direction away from the second end 12. Additionally, the intervening spaces define one or more closed-loop fluid paths for vortex flow in the lamella settling device 10.

[0075] It will be appreciated that any of the lamella settling devices 10 described with reference to Figs. 1 A to 5 may be used in the embodiment of Figs. 6A to 6C. Further, any variants or alternative embodiments disclosed herein with reference to the other figures can equally be applied to the embodiment of Figs. 6Ato 6C.

[0076] The outlet portion 30 comprises a tubular element 32 having a laterally extending portion 32a fluidically connecting the lamella outlet portion 30 to a drainage outlet of a rainwater drainage system, namely chamber outlet 92 of chamber 90. It will be appreciated that in some embodiments the laterally extending portion 32a is not provided without departing from the scope of the invention. The laterally extending portion 32a may be configured to connect to the drainage outlet by any suitable connecting mechanism known in the art, such as a press-fit connection, threaded or screw-fit connection, a compression fit connection and the like. The settling device also comprises a T-junction 33 such as a T-piece which connects the outlet portion to both the laterally extending portion 32a and an upper portion 32b of the tubular element 31.

[0077] The settling device of Figs. 6Ato 6C further comprises a flow guide 60 upstream of the lamella inlet portion 20 for inducing vortex flow in the settling device. In particular, the chamber 90 comprises a chamber inlet 91 which includes a tangentially extending portion 91a. As water flows into the chamber 90 via inlet 91, the tangentially extending portion 91a induces vortex flow within the chamber 90 and outside of the lamella settling device 10, indicated by the dashed arrow A in Fig. 6B. This vortex flow then enters the lamella settling device 10 as indicated by the arrows B. Due to the shape of the intervening spaces in the lamella settling device 10, the vortex flow continues inside the lamella settling device 10 and provides an increased flow path for the water between the inlet portion 20 and the outlet portion 30. The water then flows to the chamber outlet 92 via the laterally extending portion 32a, indicated by the arrow C.

[0078] The tangentially extending portion 91a may be considered a flow diverter for diverting radial flow (from inlet 91) to tangential flow to induce vortex flow in the settling device. It will be appreciated that the tangentially extending portion 91a may extend partially tangentially and partially radially, without departing from the scope of the disclosure.

[0079] It is also noted that inlet 91 may already extend tangentially such that a bend or flow diverter is not needed. Secondly, a flow diverter may alternatively be formed on another part of the settling device rather than as part of the inlet. For example, as described with reference to Figs. 7 A to 7D, the flow diverter may instead be provided on the lamella settling device 10.

[0080] The tubular element 32 illustrated in Figs. 6Ato 6C further extends along the longitudinal axis L and traverses the lamella settling device 10, to provide access to a second side of the settling device (below end 11) from a first side of the settling device at the upper portion 32b (above end 12). This provides the user with an access route for inserting a cleaning tool to clean the area of the inspection chamber 90 below the lamella settling device 10, without having to remove the lamella settling device 10. In particular, particulate matter settled at the bottom of the chamber 90 may be removed using a cleaning tool inserted through the tubular element 32.

[0081] In the embodiment of Figs. 6Ato 6C, the settling elements 40 are located on an outer surface of the tubular element 32 and extend radially outwards from the outer surface. Additionally, the one or more fluid outlets include fluid ports (slots 36) traversing the tubular element 32 to connect the intervening spaces to an interior space of the tubular element 32. However, it will be appreciated that in other embodiments the settling elements 40 may not be located on an outer surface of the tubular element 32. For example, the settling elements 40 may be mounted to one another by any suitable mounting structure, or may be mounted directly to the wall of the inspection chamber, and further may be configured to connect directly to the outlet 92 of the inspection chamber 90 without an intermediate tubular element such as tubular element 32.

[0082] The settling device illustrated in Figs. 6A to 6C further comprises a collection tray 70 configured to be placed beneath the first end 11 of the lamella settling device 10, such that in use, particulate matter falling from the lamella surfaces 41 as a result of gravity is collected by the collection tray 70. Whilst not illustrated, the collection tray may comprise one or more baffles for inhibiting vortex flow about the collection tray. In the illustrated embodiment, the collection tray 70 is inclined relative to the longitudinal axis L, such that in use, particulate matter falling from the lamella surfaces 41 as a result of gravity falls towards an inner portion 71 of the collection tray 70. This allows the particulate matter to be collected in a central region of the inspection chamber 90 which facilitates cleaning of the particulate matter from the chamber 90. Further, in the illustrated embodiment of Figs. 6Ato 6C, the tubular element 32 is aligned with the inner portion 71 of the collection tray 70 so that a cleaning tool has direct access to the area where particulate matter settles. It will be appreciated that in other embodiments, the tubular element 32 is not necessarily aligned with the inner portion 71.

[0083] Fig. 7A shows a side view of a settling device comprising a lamella settling device 10 according to one or more embodiments. Fig. 7B shows a schematic cutaway perspective view of the settling device shown in Fig. 7A. Fig. 7C shows a schematic cutaway perspective view of the lamella settling device 10 shown in Figs. 7A and 7B in an inspection chamber 90, with a wall of the inspection chamber 90 partly cutaway to illustrate the interior of the inspection chamber 90. Fig. 7D shows a schematic top view of the inspection chamber 90 and lamella settling device 10 shown in Fig. 7C. Certain reference numerals are shown in some of Figs. 7Ato 7D and omitted in others, for brevity, although Figs. 7Ato 7D relate to the same embodiment.

[0084] The settling device may be provided separately to the inspection chamber 90 of a rainwater drainage system (as shown in Figs. 7A and 7B), such as in the form of an insert, or may be provided with the inspection chamber 90 as shown in Figs. 7C and 7D. The settling device comprises a lamella settling device 10 comprising a first end 11, a second end 12 opposite the first end 11 and a longitudinal axis L extending between the first end 11 and second end 12. The lamella settling device 10 comprises a lamella inlet portion 20 and a lamella outlet portion 30. The lamella inlet portion 20 comprises a plurality of fluid inlets 21 (only the uppermost one is labelled in Fig. 7A, for brevity). The lamella outlet portion 30 comprises, for each fluid inlet 21, a plurality of respective fluid outlets (unlabelled for brevity) spaced apart from the respective fluid inlet 21 along the longitudinal axis L towards the second end 12 of the lamella settling device 10. The outlets are not illustrated but may comprise for example, one or more longitudinally extending slots as described with reference to Figs. 6Ato 6C, such that each slot extends across multiple settling elements 40 and intervening spaces (unlabelled for brevity) and comprises multiple outlets across multiple intervening spaces. The settling device additionally comprises a plurality of settling elements 40 (only one is labelled the figures, for brevity). Each of the settling elements 40 comprise one or more lamella surfaces (unlabelled, for brevity) inclined with respect to the longitudinal axis L, and are additionally spaced apart along the longitudinal axis L to define the intervening spaces fluidically connecting the lamella inlet portion 20 and the lamella outlet portion 30. In use, the longitudinal axis L is approximately vertical, and the lamella surfaces are therefore inclined relative to the vertical. As a result of the inclination of the lamella surfaces relative to the vertical, when fluid passes through the one or more intervening spaces from the lamella inlet portion 20 to the lamella outlet portion 30, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end 12. Additionally, the intervening spaces define one or more closed-loop fluid paths for vortex flow in the lamella settling device 10.

[0085] It will be appreciated that any of the lamella settling devices 10 described with reference to Figs. 1 A to 6C may be used in the embodiment of Figs. 7A to 7D. Further, any variants or alternative embodiments disclosed herein with reference to the other figures can equally be applied to the embodiment of Figs. 7Ato 7D.

[0086] The outlet portion 30 comprises a tubular element 32 having a laterally extending portion 32a fluidically connecting the lamella outlet portion 30 to a drainage outlet of a rainwater drainage system, namely chamber outlet 92 of chamber 90. It will be appreciated that in some embodiments the laterally extending portion 32a is not provided without departing from the scope of the invention. The laterally extending portion 32a may be configured to connect to the drainage outlet by any suitable connecting mechanism known in the art, such as a press-fit connection, threaded or screw-fit connection, a compression fit connection and the like. The settling device also comprises a T-junction 33 such as a T-piece which connects the outlet portion 30 to both the laterally extending portion 32a and an upper portion 32b of the tubular element 31.

[0087] The settling device of Figs. 7Ato 7D further comprises a flow guide 60 upstream of the lamella inlet portion 20 for inducing vortex flow in the settling device. In particular, the lamella settling device 10 comprises a flow diverter 65. As water flows into the chamber 90 via inlet 91, the water meets flow diverter 65 and is diverted into a tangential flow path, indicated by the dashed arrow in Fig. 7D, resulting in vortex flow within the chamber 90 and outside of the lamella settling device 10. This vortex flow then enters the lamella settling device 10. Due to the shape of the intervening spaces in the lamella settling device 10, the vortex flow continues inside the lamella settling device 10 and provides an increased flow path for the water between the inlet portion 20 and the outlet portion 30. The water then flows to the chamber outlet 92 via the laterally extending portion 32a. The flow diverter 65 may be mounted directly to tubular element 32 or otherwise formed on the outer surfaces of the tubular element 32 (for example it may be formed unitarily with the tubular element 32). However, it will be appreciated that alternatively or additionally, the flow diverter 65 may be mounted to other elements in the settling device such as an inner surface of the chamber 90 or to inlet 91. It is also noted that inlet 91 may already extend tangentially such that a flow diverter 65 is not needed.

[0088] In the settling device of Figs. 7Ato 7D, the settling elements 40 are located on an outer surface of the tubular element 32 and extend radially outwards from the outer surface of tubular element 32. Further, the fluid outlets include fluid ports traversing the tubular element 32 to connect the intervening spaces to an interior space of the tubular element 32, such as the slots 36 described with reference to Fig. 6B. The tubular element 32 may be considered a first tubular element 32, and the settling device further comprises a second tubular element 34 fluidically isolated from the first tubular element 32. The second tubular element 34 extends along the longitudinal axis L and traverses the lamella settling device 10, to provide access to a second side of the settling device from a first side of the settling device. Fluidically isolating the second tubular element 34 from the tubular element 32 prevents untreated water (that is, water containing the particulate matter) from bypassing the lamella settling device 10 and thus assists in achieving a higher filtration rate. In the illustrated embodiment, the second tubular element 34 is nested inside the tubular element 32 although it will be understood that other configurations are contemplated (for example in other parallel configurations, including parallel and non-nested). The second tubular element 34 may be connected to the settling device by any suitable means. For example, the second tubular element 34 may comprise one or more protrusions 34a, such as one or more legs or flanges, configured to abut the top of the tubular element 32 when the second tubular element 34 is fully inserted into the tubular element 32. Alternatively, or additionally, the second tubular element 34 may be mounted to the first tubular element 32 by any suitable means, such as welding, adhesive or by one or more fastening elements.

[0089] In preferred embodiments, the second tubular element 34 is removably mounted to first tubular element 32. For example, the second tubular element 34 may merely rest on the top of the tubular element 32 by one or more protrusions. Alternatively or additionally, the second tubular element 34 may be removably connected by any suitable reversable connecting mechanism, such as a screw thread on the outer surfaces of the second tubular element 34 configured to mate with a corresponding screw thread on the first tubular element 32, or one or more latches, hooks, fasteners, magnetic connectors, press-fit joints, clamps and the like, which may be selectively connected and disconnected to mount and dismount the second tubular element 34 from the first tubular element 32. Allowing the second tubular element 34 to be removable allows the lamella surfaces to be accessed by a cleaning tool from the upper side of the settling device, without having to remove the entire settling device from its deployed location. For example, direct access to the lamella surfaces with a pressure washer or other cleaning tool from the upper side of the settling device is enabled.

[0090] The settling device may further comprise an annular floor 35 extending inwardly from a bottom portion of the first tubular element 32, as shown in Fig 7B, configured to fluidically isolate the interior space of the first tubular element 32 with a space outside of the lamella settling device 10 proximal end 11. Together with the outer surface of second tubular element 34 and inner surface of first tubular element 32, an annular interior space is defined which is fluidically isolated from the chamber 90 except for via the outlets of the lamella settling device 10. The annular floor 35 prevents water from passing into the tubular element 32 without passing through the settling elements 40 and intervening spaces 50. The annular floor 35 also leaves open the bottom end of the second tubular element 34 so that access for cleaning is still provided. The annular floor 35 may be provided as part of one of the first or second tubular elements 32, 34, or provided as a separate element mounted to the first and / or second tubular elements 32, 34.

[0091] The settling elements 40 may each comprise one or more settling element parts. Additionally, as illustrated in Figs. 7A to 7C the settling device may further comprise a mounting structure 38 for mounting the one or more settling element parts to form the one or more lamella surfaces inclined with respect to the longitudinal axis L. The mounting structure 38 is configured to mount the one or more settling element parts at one or more locations away from the one or more intervening spaces, such that the mounting structure 38 does not obstruct the closed-loop fluid paths for vortex flow. In other words, the mounting structure 38 includes mounting portions to which the settling element parts are mounted, such as inner and outer lips or ribs 38a and 38b shown in Fig. 7B, whilst maintaining an open interior space 38c for receiving the vortex flow unobstructed. Providing a mounting structure 38 allows for the settling elements 40 to be mounted together separately to the tubular element 32, and subsequently being mounted collectively to the tubular element 32, which increases ease of assembly. When each settling element 40 comprises multiple parts, the mounting structure 32 provides a structure to mount the parts to in order to form each settling element 40. Additionally, provision of an outer mounting portion such as outer lips or ribs 38b provides support at the outer portion of each settling element 40, preventing fluid flow from causing vibrations and deflections of the lamella surfaces which could in turn affect the vortex flow and thus filtration.

[0092] It will be appreciated that the mounting structure 38 could be mounted or connected to the settling device by any suitable means. For example, the mounting structure 38 may be mounted to the outer surface of the tubular element 32 by any suitable means, such as by welding, adhesive or by one or more fastening means such as one or more screws. Alternatively, or additionally, the mounting structure 38 may be mounted to, or otherwise supported by the chamber 90. For example, the mounting structure 38 may comprise one or more legs 38d configured to rest on one or more corresponding protrusions or supports 90a extending inwardly from the chamber 90. The settling elements can therefore be rested in the chamber 90 and do not require more complex structures such as hanging support structures which hang the settling elements from above. The mounting structure may therefore, in some embodiments, be free from hanging elements configured to hang the settling elements.

[0093] The settling device illustrated in Figs. 7A to 7D further comprises a collection tray 70 configured to be placed beneath the first end 11 of the lamella settling device 10, such that in use, particulate matter falling from the lamella surfaces 41 as a result of gravity is collected by the collection tray 70. Fig. 8 shows a perspective view of the collection tray 70 of Figs. 7Ato 7D in isolation. The collection tray 70 may comprise one or more baffles 80 for inhibiting vortex flow about the collection tray 70. In the illustrated embodiment, the collection tray 70 is inclined relative to the longitudinal axis L, such that in use, particulate matter falling from the lamella surfaces 41 as a result of gravity falls towards an inner portion 71 of the collection tray 70. The collection tray may be fustoconical in shape as illustrated or any other suitable concave shape. This allows the particulate matter to be collected in a central region of the inspection chamber 90 which facilitates cleaning of the particulate matter from the chamber 90. Further, in the illustrated embodiment of Figs. 7A to 7D, the second tubular element 34 is aligned with the inner portion 71 of the collection tray 70 so that a cleaning tool has direct access to the area where particulate matter settles. It will be appreciated that in other embodiments, the second tubular element 34 is not necessarily aligned with the inner portion 71.

[0094] Fig. 9 shows a perspective view of a baffle device 85 which may be used in any of the settling devices disclosed herein. The baffle device 85 may be used in place of, or in addition to, the collection trays disclosed herein. The baffle device 85 comprises a plurality of circumferentially spaced baffles 80 for inhibiting vortex flow. It may be placed proximal end 11 of the settling device 10 to inhibit vortex flow below the settling device, to encourage settling of the separated particles. The baffles may be inclined to the vertical as illustrated, or may be vertical.

[0095] Fig. 10 shows a schematic view of a rainwater drainage system 100 including a settling device according to one or more embodiments. The system 100 includes a rainfall collection area 101 which may be, for example, a rainfall collection area 101 of an urban environment such as a building or driveway. The system includes an inspection chamber 90, and may include one or more upstream elements 102 upstream of chamber 90, such as one or more channel drains, gullies and manholes. The system may further comprise one or more downstream elements 103 downstream of the chamber 90, such as one or more storage or infiltration devices and pumping elements. The chamber 90 may be any of the inspection chambers 90 described herein and may include any of the settling devices described herein. The settling devices advantageously provide effective removal of particulate matter from rainwater received from the rainfall collection area 101.

[0096] Fig. 11 A shows a schematic cross-sectional side view of a settling device 10 according to one or more embodiments. Fig. 11B shows a schematic perspective view of the settling device 10 shown in Fig. 11 A. Fig. 11C shows a schematic side view of the settling device 10 shown in Fig. 11A. The settling device 10 shown in Figs. 1 lAto 11C is similar to the embodiment shown and described with reference to Figs. 7Ato 7D, and may comprise all of the features of those embodiments. Reference numerals for some of the features already described with reference to Figs. 7A to 7D are omitted from Figs. HA to 11C, for brevity. In the embodiment shown in Figs. HAto 11C, the settling device 10 additionally comprises an overflow opening 66 located above the lamella settling element 40 (that is, between the lamella settling elements 40 and the second end 12), and as shown in the figures, may also be located above the portion 32a which connects to the drainage outlet. The overflow opening 66 provides a secondary fluid route through the device 10, which bypasses the lamella settling elements 40, in the event that a high amount of rainwater floods the system and a higher flow rate through the device 10 is required to drain the water. Due to the position of the overflow opening 66 above the settling elements 40 and optionally above the portion 32a which connects to the drainage outlet, the fluid route is only accessible when the water level in the drainage system (e.g. the inspection chamber) is high, corresponding to a flooding event.

[0097] The flow diverter 65 further surrounds the overflow opening 66 to form an enclosure surrounding the overflow opening 66. The enclosure obstructs fluid from reaching the opening 66 except for an overflow inlet 67 at a lower end of the flow diverter 65 (i.e., displaced from the overflow opening 66 towards the first end 11). Thus, in use, during a flooding event, fluid above the overflow inlet 67 must travel in a tortuous path as indicated by the arrow P in Fig. 11 A. This tortuous path P inhibits floatable particulate matter from bypassing the device 10 through the opening 66, as the floatable particulate matter will tend to float above the overflow inlet 67 and will thus have no route to the opening 66 in a flooding event.

[0098] Advantageously, the flow diverter 65 surrounding the overflow opening 66 as described above allows this single element to act as both the flow diverter 65 and as a filter for floatable matter through the overflow opening 66. This both reduces the complexity of the design of the device 10, and also avoids the use of a further enclosure which may inhibit vortex flow about the inspection chamber. However, it will be appreciated that in other embodiments, the flow divert 65 may be provides separately and the device may comprise a surrounding wall forming the enclosure surrounding the overflow opening 66 as described above. It will be appreciated that the overflow opening 66 and surrounding enclosure including the overflow inlet 67 may be provided in any of the other embodiments disclosed herein, and in particular with reference to any of the preceding figures.

[0099] In some embodiments, fluid external to the device 10 may reach the outlet portion 30 only via inlet portion 20 or overflow opening 66.

[0100] It will also be appreciated that in the illustrated embodiments, the settling devices are about concentric with the inspection chamber to encourage vortex flow in the inspection chamber. It will be appreciated that in other embodiments, the settling device may be offset from a centre of the inspection chamber, although this may reduce vortex flow.

[0101] It will be appreciated that the dimensions of the lamella settling devices described above with references to Figs. lAto 1C, 2 to 5, 6Ato 6C, 7Ato 7D, and HAto 11C, such as the length of the respective lamella settling devices 10 along the longitudinal axis L, the diameter of the lamella settling device 10, the size of the intervening spaces 50, and sizes of the inlets 21 and outlets 31 may take any suitable values depending on the application, For example, the dimensions make be selected based on the rainwater drainage system that it is configured for.

[0102] Similarly, for any of the lamella settling devices described above with references to Figs. 1A to 1C, 2 to 5, 6Ato 6C, 7A to 7D, and HAto 11C, the shape and number of the inlets 21 and respective outlets 31 may take any suitable shape and number, and each inlet 21 or outlet 31 may be identical or different in shape or size to other inlets 21 and outlets 31.

[0103] It will also be appreciated the settling elements 40 take any suitable form which provides one or more lamella surfaces 41 which are inclined to the longitudinal axis. For example, the settling elements 40 may be conical, pyramidical, frustoconical, frustopyramidical or any other form, such as a plurality of inclined planar or curved plates. Whilst the settling elements 40 are shown as being convex, stacked and nested such that a convex side of one settling element 40 is contained within the concave space of the neighbouring settling element 40, in other embodiments the settling elements 40 may not be stacked or nested.

[0104] It will further be appreciated that the sloping angle taken by each of the lamella surfaces 41 may take any suitable angle. Further, each lamella surface 41 may have identical sloping angles or they may have different sloping angles. Also, each lamella surface may have different portions or areas which each have different sloping angles.

[0105] It is noted that the settling elements 40 may take any suitable shape. In the illustrated embodiments, the settling elements 40 are free from ribs, weirs, or any other similar protrusions that may inhibit vortex flow along their surface and / or in the intervening spaces.

[0106] Also disclosed herein is a method of manufacturing a settling device for a rainwater drainage system. The method may be performed to provide any of the settling devices disclosed herein, including those with reference to the drawings. Like numerals will be used in the following to better understand how the method may be applied to the settling devices described with reference to the drawings. The method comprises providing a lamella settling device 10, including providing a plurality of settling elements 40, wherein the lamella settling device comprises a first end 11, a second end 12 opposite the first end 11 and a longitudinal axis L extending between the first end 11 and second end 12, the lamella settling device 10 comprising: a lamella inlet portion 20 comprising one or more fluid inlets 21; a lamella outlet portion 30 comprising, for each fluid inlet 21, one or more respective fluid outlets 31 spaced apart from the respective fluid inlet 21 along a longitudinal axis L. The plurality of settling elements 40 each comprise one or more lamella surfaces 41 inclined with respect to the longitudinal axis L. The plurality of settling element 40 are spaced apart along the longitudinal axis L to define one or more intervening spaces 50 fluidically connecting the lamella inlet portion 20 and the lamella outlet portion 30, such that in use, when fluid passes through the one or more intervening spaces 50 from the lamella inlet portion 20 to the lamella outlet portion 30, particulate matter in the fluid settles on the lamella surfaces 41 as a result of gravity in a direction away from the second end 12. At least some of the one or more intervening spaces 50 define one or more closed-loop fluid paths for vortex flow in the lamella settling device 10.

[0107] The method may comprise forming the plurality of settling elements 40 prior to providing the plurality of settling elements 40, such as by a molding process.

[0108] In some embodiments of the method of manufacture, the plurality of settling elements 40 may be assembled from a disassembled condition into an assembled condition in which the plurality of settling elements 40 are spaced apart along the longitudinal axis L to define the one or more intervening spaces 50 which fluidically connect the lamella inlet portion 20 and the lamella outlet portion 30.

[0109] In some embodiments, a flow guide 60 may be provided upstream of the lamella inlet portion 20 for inducing vortex flow in the settling device. The flow guide 60 may be, for example, a flow diverter 65 for diverting radial flow to tangential flow to induce vortex flow in the settling device. The flow guide 60 may be formed prior to providing the flow guide 60, for example by a molding process. The method may include mounting the flow diverter 65 to the settling device at a position upstream of the lamella inlet portion 20.

[0110] In some embodiments, the plurality of settling elements 40 includes a plurality of stacked nested concave settling elements 40 to form a plurality of stacked nested lamella surfaces 41, which may be at least partially conical forming a plurality of at least partially conical or pyramidical lamella surfaces 41. The stacked nested convex settling elements 40 may frustoconical such as illustrated in the figures, or frustopyramidical, forming a plurality of frustoconical or frustopyramidical lamella surfaces 41. In some embodiments, the plurality of settling elements 41 are assembled from a disassembled condition into an assembled condition by stacking and nesting the plurality of settling elements 41 so that they are spaced apart along the longitudinal axis L, such as shown in the figures, to define one or more intervening spaces 50 fluidically connecting the lamella inlet portion 20 and the lamella outlet portion 30.

[0111] In some embodiments of the method, one or more of the fluid inlets 21 are located at a radially outer portion of the one or more intervening spaces 50 and one or more of the respective fluid outlets 31 are located at a radially inner portion of the one or more intervening spaces 50.

[0112] In some embodiments, the method comprises providing a tubular element 32 or 34 extending at least along the longitudinal axis L and traversing the lamella settling device 10, to provide access to a second side of the settling device from a first side of the settling device, such as shown in Figs. 6Ato 6C, 7C and 7D. The method may comprise forming the tubular element 32 or 34 prior to providing the tubular element 32 or 34, such as by a molding process.

[0113] In some embodiments, providing the lamella settling device 10 may include the step of providing a tubular element 32 including fluid ports 36 traversing the tubular element 32, and providing the plurality of settling elements 40 may include the step of providing the settling elements 40 on an outer surface of the tubular element 32 such that they extend radially outwards from the outer surface, such that the lamella outlet portion 30 comprises the tubular element 32, and the one or more fluid outlets 31 include the fluid ports 36 traversing the tubular element 32 to connect the intervening spaces 50 to an interior space of the tubular element 32. An example of such a resulting settling device is shown in Fig. 6B. The step of providing the tubular element 32 may comprise forming the tubular element 32 prior to providing the tubular element 32, such as by a molding process. The settling elements 40 may be provided on the outer surface of the tubular element 32 by mounting the plurality of settling elements 40 to the outer surface.

[0114] In some embodiments, providing the lamella settling device 10 may include the step of providing a first tubular element 32 including fluid ports 36 traversing the first tubular element 32, and providing the plurality of settling elements 40 may include the step of providing the settling elements 40 on an outer surface of the first tubular element 32 such that they extend radially outwards from the outer surface, such that the lamella outlet portion 30 comprises the first tubular element 32, and the one or more fluid outlets 31 include the fluid ports 36 traversing the first tubular element 32 to connect the intervening spaces 50 to an interior space of the first tubular element 32. Furthermore, the method may comprise providing a second tubular element 34 extending at least along the longitudinal axis L and traversing the lamella settling device 10, to provide access to a second side of the settling device from a first side of the settling device, the second tubular element 34 fluidically isolated from the first tubular element 34. An example of the resulting device is shown in Fig. 7B. The step of providing the first tubular element 32 may comprise forming the first tubular element 32 prior to providing the tubular element 32, such as by a molding process. Similarly, the step of providing the second tubular element 34 may comprise forming the second tubular element 34 prior to providing the second tubular element 34, such as by a molding process. The settling elements 40 may be provided on the outer surface by mounting the plurality of settling elements 40 to the outer surface. Additionally, in some embodiments the step of providing the second tubular element 34 may include the step of inserting the second tubular element 34 inside the first tubular element 32 and fixing the second tubular element 34 relative to the first tubular element 32 so that the second tubular element 34 is nested inside the first tubular element 32.

[0115] In some embodiments, providing the lamella settling device 10 may include the step of providing a laterally extending portion 32a extending at least radially outward, for fluidically connecting the lamella outlet portion 30 to a drainage outlet (e.g. outlet 92) of a rainwater drainage system.

[0116] In some embodiments, providing the lamella settling device may include the step of providing one or more baffles 80, such as on a collection tray as shown in Fig. 8 or as part of a baffle device as shown in Fig. 9, the one or more baffles 80 proximal the first end 11 for inhibiting vortex flow.

[0117] In some embodiments of the method the tubular element may be provided to be aligned with the inner portion 71 of the collection tray 70.

[0118] In some embodiments, the step of providing a plurality of settling elements 40 may include the step of providing one or more settling element parts and providing a mounting structure 38 for mounting the one or more settling element parts to form the one or more lamella surfaces 41 inclined with respect to the longitudinal axis L. The method may comprise mounting the one or more settling element parts to the mounting structure 38 at one or more locations away from the one or more intervening spaces 50, such that the mounting structure 38 does not obstruct the closed-loop fluid paths for vortex flow, such as shown in Fig. 7B.

[0119] In some embodiments, the step of providing the one or more settling element parts may comprise forming the one or more settling element parts prior to providing the one or more settling element parts such as by a by a molding process. Similarly, the step of providing the mounting structure 38 may comprise forming the mounting structure 38 prior to providing the mounting structure 38 such as by a by a molding process.

[0120] In embodiments where the lamella settling device 10 is an insert configured to be placed inside a rainwater drainage system, the method may comprise inserting the lamella settling device 10 into the rainwater drainage system (such as into chamber 90) and fluidically connecting the lamella settling device 10 to the rainwater drainage system (such as by fluidically connecting the outlet portion 30 to chamber outlet 92 via laterally extending portion 32a.

[0121] The settling devices disclosed herein may be used for the following method. Firstly, A vortex flow of rainwater is provided at the lamella inlet portion 20, such as by use of the flow guide 60. The rainwater then flows through the plurality of settling elements 40 and out of the lamella outlet portion 30. When the rainwater passes through the one or more intervening spaces 50 from the lamella inlet portion 20 to the lamella outlet portion 30, particulate matter in the fluid settles on the lamella surfaces 41 as a result of gravity in a direction away from the second end 12 to provide treated rainwater at the outlet portion 30.

[0122] In embodiments where the settling device is an insert, when the settling device is provided in an inspection chamber 90, the lamella settling device 10 may be removed from the inspection chamber 90 and the settling device and / or the inspection chamber 90 may be cleaned.

[0123] In embodiments comprises tubular element 32 or 34 extending at least along the longitudinal axis L and traversing the lamella settling device 10, providing access to a second side of the settling device from a first side of the settling device, a cleaning tool may be extended through the tubular element 32 or 34 and the second side of the settling device may be cleaned using the cleaning tool.

[0124] The components of the lamella settling device, as well as the collection tray, baffles and flow guides for any embodiments disclosed herein may be made of any suitable material. For example, the components may be made of any suitable plastic or thermoplastic, ceramic or metal such as stainless steel. Similarly, the inspection chamber in which the settling device is located may also be made of any material, of any suitable plastic or thermoplastic, ceramic or metal such as stainless steel, or concrete.

[0125] It will also be appreciated that features described with respect to one figure may equally be applied to an embodiment described with respect to another figure. For example, the shapes or forms of an element described with respect to one figure may be also taken for the same element of another figure. For example, any of the lamella settling devices described with reference to Figs. lAto 5 may be utilized in the inspection chamber shown in Figs. 6Ato 6C, and the outlets described with references to Figs. 1A to 1C and Fig. 6B may be used in any of the other embodiments. Similarly, the mounting structure described with reference to Figs. 7A to 7D may be used in any other embodiment. These examples are non-exhaustive, and any other element described with reference to one figure may be exchanged with any equivalent element described with reference to another figure.

[0126] Whilst the illustrated embodiments all comprise intervening spaces which define one or more closed-loop fluid paths for vortex flow, it will be appreciated that the scope of the invention is not necessarily limited to such lamella settling devices. In particular, in some embodiments one or more (or all) of the intervening spaces may not define any closed-loop fluid paths, for example by comprising intervening walls, ribs, baffles or the like which prevent circumferential flow within the intervening spaces. In such embodiments, the lamella settling device may be placed in a chamber of a stormwater drainage system, and sized such that the vortex flow is able to occur inside the chamber but externally to the lamella settling device.

[0127] Such a system will still benefit from the combined effect of hydrodynamic separation and particulate separation using a lamella device.

[0128] All of the above are fully within the scope of the present disclosure, and are considered to form the basis for alternative embodiments in which one or more combinations of the above- described features are applied, without limitation to the specific combination disclosed above.

[0129] In light of this, there will be many alternatives which implement the teaching of the present disclosure. It is expected that one skilled in the art will be able to modify and adapt the above disclosure to suit its own circumstances and requirements within the scope of the present disclosure, while retaining some or all technical effects of the same, either disclosed or derivable from the above, in light of his common general knowledge in this art. All such equivalents, modifications or adaptations fall within the scope of the present disclosure.

Claims

CLAIMS1. A settling device for a rainwater drainage system, comprising: a lamella settling device comprising a first end, a second end opposite the first end and a longitudinal axis extending between the first end and second end, the lamella settling device comprising: a lamella inlet portion comprising one or more fluid inlets; a lamella outlet portion comprising, for each fluid inlet, one or more respective fluid outlets spaced apart from the respective fluid inlet along the longitudinal axis towards the second end of the lamella settling device; a plurality of settling elements, the plurality of settling elements each comprising one or more lamella surfaces inclined with respect to the longitudinal axis, the plurality of settling elements spaced apart along the longitudinal axis to define one or more intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion; such that in use, when fluid passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end.

2. The settling device according to claim 1, wherein at least some of the one or more intervening spaces define one or more closed-loop fluid paths for vortex flow in the lamella settling device.

3. The settling device according to claim 1 or 2, wherein the lamella settling device is an insert configured to be placed inside a rainwater drainage system.

4. The settling device according to any preceding claim, wherein the settling device is for an inspection chamber of a rainwater drainage system.

5. The settling device according to any preceding claim, further comprising a flow guide upstream of the lamella inlet portion for inducing vortex flow about the settling device.

6. The settling device according to claim 5, wherein the flow guide comprises a flow diverter for diverting radial flow to tangential flow to induce vortex flow about the settling device.

7. The settling device according to any preceding claim, wherein the plurality of settling elements includes a plurality of stacked nested concave settling elements to form a plurality of stacked nested lamella surfaces.

8. The settling device according to claim 7, wherein the stacked nested concave settling elements are at least partially conical or pyramidical settling elements forming a plurality of at least partially conical or pyramidical lamella surfaces.

9. The settling device according to claim 8, wherein the stacked nested convex settling elements are frustoconical or frustopyramidical settling elements forming a plurality of frustoconical or frustopyramidical lamella surfaces.

10. The settling device according to any preceding claim, wherein one or more of the fluid inlets are located at a radially outer portion of the one or more intervening spaces and one or more of the respective fluid outlets are located at a radially inner portion of the one or more intervening spaces.

11. The settling device according to any preceding claim, further comprising a tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device.

12. The settling device according to any preceding claim, wherein the lamella outlet portion comprises a tubular element, and wherein the settling elements are located on an outer surface of the tubular element and extend radially outwards from the outer surface; wherein the one or more fluid outlets include fluid ports traversing the tubular element to connect the intervening spaces to an interior space of the tubular element.

13. The settling device according to any of claims 1 to 10, wherein the lamella outlet portion comprises a first tubular element, and wherein the settling elements are located on an outer surface of the first tubular element and extend radially outwards from the outer surface; wherein the one or more fluid outlets include fluid ports traversing the first tubular element to connect the intervening spaces to an interior space of the first tubular element; the settling device further comprising a second tubular element fluidically isolated from the first tubular element, the second tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device.

14. The settling device according to claim 13, wherein the second tubular element is nested inside the first tubular element, optionally wherein the second tubular element is removably mounted to the first tubular element.

15. The settling device according to any preceding claim, wherein the lamella outlet portion comprises a laterally extending portion extending at least radially outward, for fluidically connecting the lamella outlet portion to a drainage outlet of a rainwater drainage system.

16. The settling device according to any preceding claim, further comprising one or more baffles configured to be placed beneath the first end of the lamella settling device for inhibiting vortex flow.

17. The settling device according to any preceding claim, further comprising a collection tray configured to be placed beneath the first end of the lamella settling device, such that in use, particulate matter falling from the lamella surfaces as a result of gravity is collected by the collection tray.

18. The settling device according to claim 17, wherein the collection tray comprises one or more baffles for inhibiting vortex flow about the collection tray.

19. The settling device according to claim 17 or 18, wherein the collection tray is inclined relative to the longitudinal axis, such that in use, particulate matter falling from the lamella surfaces as a result of gravity falls towards an inner portion of the collection tray.

20. The settling device according to claim 18, when comprising a tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device; wherein the tubular element is aligned with the inner portion of the collection tray.

21. The settling device according to any preceding claim, wherein at least some, and preferably all, of the lamella surfaces are inclined relative to the first end by an angle sufficiently steep to inhibit particulate matter from settling on said lamella surfaces, optionally by an angle of 45° or less.

22. The settling device according to any preceding claim, wherein for at least one inlet and respective outlet for one or more intervening spaces, the distance between the inlet and the outlet is given by d, and a depth D of the intervening space is less than d.

23. The settling device according to claim 22, wherein a depth D of the intervening space is less than 0.5d, and more preferably less than 0.25d, even more preferably less than O. ld.

24. The settling device according to any preceding claim, wherein one or more settling elements comprise one or more settling element parts; the settling device further comprising a mounting structure for mounting the one or more settling element parts to form the one or more lamella surfaces inclined with respect to the longitudinal axis; wherein the mounting structure is configured to mount the one or more settling element parts at one or more locations away from the one or more intervening spaces, such that the mounting structure does not obstruct the closed-loop fluid paths for vortex flow.

25. The settling device according to any preceding claim, further comprising a chamber in which the lamella settling device is situated, the chamber comprising a chamber inlet and a chamber outlet, wherein the lamella outlet portion of the lamella settling device is fluidically connected to the chamber outlet.

26. The settling device according to claim 25, wherein the chamber is an inspection chamber of a rainwater drainage system.

27. A method of manufacturing a settling device for a rainwater drainage system, comprising: providing a lamella settling device, including providing a plurality of settling elements, wherein the lamella settling device comprises a first end, a second end opposite the first end and a longitudinal axis extending between the first end and second end, the lamella settling device comprising: a lamella inlet portion comprising one or more fluid inlets; a lamella outlet portion comprising, for each fluid inlet, one or more respective fluid outlets spaced apart from the respective fluid inlet along a longitudinal axis; the plurality of settling elements each comprising one or more lamella surfaces inclined with respect to the longitudinal axis, the plurality of settling elements spaced apart along the longitudinal axis to define one or more intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion; such that in use, when fluid passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluidsettles on the lamella surfaces as a result of gravity in a direction away from the second end.

28. The method according to claim 27, wherein at least some of the one or more intervening spaces define one or more closed-loop fluid paths for vortex flow in the lamella settling device.

29. The method according to claim 27 or 28, wherein the method comprises forming the plurality of settling elements prior to providing the plurality of settling elements.

30. The method according to claim 29, wherein for at least one settling element, the step of forming the settling element comprises forming the settling element by a molding process.

31. The method according to any of claims 27 to 30, wherein the step of providing a lamella settling device includes the step of assembling the plurality of settling elements from a disassembled condition into an assembled condition in which the plurality of settling elements are spaced apart along the longitudinal axis to define one or more intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion.

32. The method according to any of claims 27 to 31, further comprising the step of providing a flow guide upstream of the lamella inlet portion for inducing vortex flow about the settling device.

33. The method according to claim 32, wherein the flow guide comprises a flow diverter for diverting radial flow to tangential flow to induce vortex flow about the settling device.

34. The method according to claim 32 or claim 33, wherein the step of providing a flow guide comprises forming the flow guide prior to providing the flow guide.

35. The method according to claim 34, wherein the step of forming the flow guide comprises forming the flow guide by a molding process.

36. The method according to any of claims 32 to 35 when the flow guide comprises a flow diverter for diverting radial flow to tangential flow, wherein the step of providing a flow diverter includes mounting the flow diverter to the settling device at a position upstream of the lamella inlet portion.

37. The method according to any of claims 27 to 36, wherein the plurality of settling elements includes a plurality of stacked nested concave settling elements to form a plurality of stacked nested lamella surfaces, preferably wherein the stacked nested concave settling elements are at least partially conical or pyramidical settling elements forming a plurality of at least partially conical or pyramidical lamella surfaces, more preferably wherein the stacked nested convex settling elements are frustoconical or frustopyramidical settling elements forming a plurality of frustoconical or frustopyramidical lamella surfaces.

38. The method according to claim 37, comprising the step of assembling the plurality of settling elements from a disassembled condition into an assembled condition by stacking and nesting the plurality of settling elements so that they are spaced apart along the longitudinal axis to define one or more intervening spaces fluidically connecting the lamella inlet portion and the lamella outlet portion.

39. The method according to any of claims 27 to 38, wherein one or more of the fluid inlets are located at a radially outer portion of the one or more intervening spaces and one or more of the respective fluid outlets are located at a radially inner portion of the one or more intervening spaces.

40. The method according to any of claims 27 to 39, further comprising providing a tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device.

41. The method according to claim 40, wherein the step of providing the tubular element comprises forming the tubular element prior to providing the tubular element.

42. The method according to claim 41, wherein the step of forming the tubular element comprises forming the tubular element by a molding process.

43. The method according to any of claims 27 to 42, wherein providing the lamella settling device includes the step of providing a tubular element including fluid ports traversing the tubular element, and providing the plurality of settling elements includes the step of providing the settling elements on an outer surface of the tubular element such that they extend radially outwards from the outer surface; such that the lamella outlet portion comprises the tubular element, and the one or more fluid outlets include the fluid portstraversing the tubular element to connect the intervening spaces to an interior space of the tubular element.

44. The method according to claim 43, wherein the step of providing the tubular element comprises forming the tubular element prior to providing the tubular element.

45. The method according to claim 44, wherein the step of forming the tubular element comprises forming the tubular element by a molding process.

46. The method according to any of claims 43 to 45, wherein the step of providing the settling elements on the outer surface of the tubular element includes mounting the plurality of settling elements to the outer surface.

47. The method according to any of claims 27 to 39, wherein providing the lamella settling device includes the step of providing a first tubular element including fluid ports traversing the first tubular element, and providing the plurality of settling elements includes the step of providing the settling elements on an outer surface of the first tubular element such that they extend radially outwards from the outer surface; such that the lamella outlet portion comprises the first tubular element, and the one or more fluid outlets include the fluid ports traversing the first tubular element to connect the intervening spaces to an interior space of the first tubular element; and further comprising providing a second tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device, the second tubular element fluidically isolated from the first tubular element.

48. The method according to claim 47, wherein the step of providing the first tubular element comprises forming the first tubular element prior to providing the first tubular element, and / or the step of providing the second tubular element comprises forming the second tubular element prior to providing the second tubular element.

49. The method according to claim 48, wherein the step of forming the first tubular element comprises forming the first tubular element by a molding process, and / or the step of forming the second tubular element comprises forming the second tubular element by a molding process.

50. The method according to any of claims 47 to 49, wherein the step of providing the settling elements on the outer surface of the first tubular element includes mounting the plurality of settling elements to the outer surface.

51. The method according to any of claims 47 to 50, wherein the step of providing the second tubular element includes the step of inserting the second tubular element inside the first tubular element and fixing the second tubular element relative to the first tubular element so that the second tubular element is nested inside the first tubular element, optionally wherein the second tubular element is removably mounted to the first tubular element.

52. The method according to any of claims 27 to 51, wherein providing the lamella settling device includes the step of providing a laterally extending portion extending at least radially outward, for fluidically connecting the lamella outlet portion to a drainage outlet of a rainwater drainage system.

53. The method according to any of claims 27 to 52, wherein providing the lamella settling device includes the step of providing one or more baffles proximal the first end for inhibiting vortex flow.

54. The method according to any of claims 27 to 53, wherein providing the lamella settling device includes providing a collection tray configured to be placed proximal the first end of the lamella settling device, such that in use, particulate matter falling from the lamella surfaces as a result of gravity is collected by the collection tray.

55. The method according to claim 54, wherein the collection tray comprises one or more baffles for inhibiting vortex flow about the collection tray.

56. The method according to claim 54 or claim 55, wherein the collection tray is inclined relative to the longitudinal axis, such that in use, particulate matter falling from the lamella surfaces as a result of gravity falls towards an inner portion of the collection tray.

57. The method according to claim 56, when comprising the step of providing a tubular element including fluid ports traversing the tubular element, and providing the settling elements on an outer surface of the tubular element such that they extend radially outwards from the outer surface; such that the lamella outlet portion comprises the tubular element, and the one or more fluid outlets include the fluid ports traversing thetubular element to connect the intervening spaces to an interior space of the tubular element; wherein the tubular element is aligned with the inner portion of the collection tray.

58. The method according to any of claims 27 to 57, wherein at least some, and preferably all, of the lamella surfaces are inclined relative to the first end by an angle sufficiently steep to inhibit particulate matter from settling on said lamella surfaces, optionally by an angle of 45° or less.

59. The method according to any of claims 27 to 58, wherein for at least one inlet and respective outlet for one or more intervening spaces, the distance between the inlet and the outlet is given by d, and a depth D of the intervening space is less than d.

60. The method according to any of claims 27 to 59, wherein the depth of the intervening space is less than 0.5d, and more preferably less than 0.25d, even more preferably less than O. ld.

61. The method according to any of claims 27 to 60, wherein the step of providing a plurality of settling elements includes the step of providing one or more settling element parts and providing a mounting structure; the mounting structure for mounting the one or more settling element parts to form the one or more lamella surfaces inclined with respect to the longitudinal axis; the method comprising mounting the one or more settling element parts to the mounting structure at one or more locations away from the one or more intervening spaces, such that the mounting structure does not obstruct the closed-loop fluid paths for vortex flow.

62. The method according to claim 61, wherein the step of providing the one or more settling element parts comprises forming the one or more settling element parts prior to providing the one or more settling element parts, and / or the step of providing the mounting structure comprises forming the mounting structure prior to providing the mounting structure.

63. The method according to claim 62, wherein the step of forming the one or more settling element parts comprises forming the one or more settling element parts by a molding process, and / or the step of forming the mounting structure comprises forming the mounting structure by a molding process.

64. The method according to any of claims 27 to 63, wherein the lamella settling device is an insert configured to be placed inside a rainwater drainage system, the method comprising inserting the lamella settling device into the rainwater drainage system and fluidically connecting the lamella settling device to the rainwater drainage system.

65. The method according to claim 64, wherein the step of inserting the lamella settling device into the rainwater drainage system includes the step of inserting the lamella settling device into an inspection chamber of the rainwater drainage system, and fluidically connecting the outlet portion of the lamella settling device to an outlet of the inspection chamber.

66. A method for separating particulate matter from rainwater using the settling device according to any of claims 1 to 26, comprising the steps of: providing a vortex flow of rainwater at the lamella inlet portion; and flowing the rainwater through the plurality of settling elements and out of the lamella outlet portion; such that when the rainwater passes through the one or more intervening spaces from the lamella inlet portion to the lamella outlet portion, particulate matter in the fluid settles on the lamella surfaces as a result of gravity in a direction away from the second end to provide filtered rainwater at the outlet portion.

67. A method for cleaning a rainwater drainage system comprising a settling device according to claim 4, or any of claims 4 to 26 when dependent on claim 3, the settling device being provided in an inspection chamber, the method comprising the step of removing the lamella settling device from the inspection chamber and cleaning the settling device and / or the inspection chamber.

68. A method for cleaning a rainwater drainage system comprising a settling device according to any of claims 1 to 26 when comprising a tubular element extending at least along the longitudinal axis and traversing the lamella settling device, to provide access to a second side of the settling device from a first side of the settling device; the method comprising the step of extending a cleaning tool through the tubular element and cleaning the second side of the settling device using the cleaning tool.

69. The settling device or method according to any preceding claim, further comprising one or more overflow openings displaced from the lamella settling elements towards the second end, the overflow opening providing a secondary fluid path to the outlet portion which bypasses the plurality of settling elements in the event of overflow.

70. The settling device or method of claim 69, further comprising a surrounding wall forming an enclosure surrounding the one or more overflow openings, the enclosure comprising an overflow inlet displaced from the overflow opening towards the first end and obstructing fluid from reaching the one or more overflow openings except via the overflow inlet.

71. The settling device or method of claim 70, wherein the surrounding wall is a flow diverter for diverting radial flow to tangential flow to induce vortex flow about the settling device.

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