AU2014234965A1 - Solids separator - Google Patents

Abstract

A solids separator comprising: a separator tank having an inlet and an outlet through which water entrained with solids can flow; an inflow passage from the inlet to a separation chamber in the tank, and an outflow passage from the separation chamber to the outlet with a solids filter located therein; a bypass passage accessed over a bypass weir that allows water to flow from the inlet to the outlet bypassing the separation chamber; and an internal wall in the separator tank that partitions an inflow chamber from the bypass passage wherein the internal wall has an opening located near the separator's inlet, and the inflow chamber and opening are located in the inflow passage.

Description

WO 2014/146178 PCT/AU2014/050005 SOLIDS SEPARATOR The present invention relates to a solids separator for use in stormwater/rainwater drainage systems to separate solids entrained in water. 5 Background Flooding caused by storms or heavy water events generate stormwater run-off that will pick up solids in its path including debris and gross pollutants as well as grit and other fine 10 particulate matter, and oils and scum. Run-off water entrained with solids enters drainage systems and will flow into public waterways and surrounding areas which can cause harm to flora and aquatic creatures, and in some cases can even harm humans. Stormwater separators are used in stormwater drains to separate and retain solids from 15 water so that the water exiting the separators is cleaner and less harmful. A problem with existing separators is that during high flows (that generally occur once every 5 years) water entering the separator experiences inherently high energy losses that create a backflow of water upstream. This is undesirable as rather than effectively draining the water the separator causes the water entrained with solids to flood back upstream and onto roads, 20 parks, and commercial and domestic areas. The back flooding problem can be exacerbated by the grade of pipe incline entering the separator whereby a steeper pipe incline will more likely cause back flooding because the larger inherent energy from water flowing in a steeper pipe will create a greater hydraulic 25 jump in the separator that can progress back upstream and cause flooding. The present invention has been brought about in view of the above problems. Summary of Invention 30 In accordance with the present invention there is provided a solids separator comprising: a separator tank having an inlet and an outlet through which water entrained with solids can flow; an inflow passage from the inlet to a separation chamber in the tank, and an outflow 35 passage from the separation chamber to the outlet with a solids filter located therein; a bypass passage accessed over a bypass weir that allows water to flow from the inlet to the outlet bypassing the separation chamber; and 1 WO 2014/146178 PCT/AU2014/050005 an internal wall in the separator tank that partitions an inflow chamber from the bypass passage wherein the internal wall has an opening located near the separator's inlet, and the inflow chamber and opening are located in the inflow passage. 5 Preferably, the internal wall of the separator forms an enclosure in the separator tank defining the inflow chamber, so that water can only enter the enclosure through the opening. In one embodiment the inflow chamber is annular and in another embodiment it is rectangular. 10 The internal wall is preferably located adjacent the bypass passage and is either directly adjacent or separated from the bypass passage by a gap. The internal wall preferably extends to a height above the bypass passage. In other words, the internal wall rises from a height in the separator that is substantially the same as the 15 bypass passage to a height above the bypass passage. In extending to a height above the bypass passage the internal wall could be a substantially vertical wall, domed or otherwise inclined relative to a horizontal plane. The opening and inlet are preferably aligned with each other in the direction of water flow, 20 which could be in a direction that is an extension of the inlet leading into the separator. This enables water that has flowed into the separator to flow directly through the opening in the internal wall and into the inflow chamber. In one embodiment, a part of the internal wall above the opening forms a baffle to minimise 25 solids flowing back upstream of the opening. In another embodiment, a separate baffle is provided across an upper part of the opening to minimize solids flowing back upstream of the opening. In this embodiment the baffle may be provided on the same side of the internal wall as the inlet (ie. on an outside of the internal wall) or on the other side of the internal wall to the inlet (ie. on an inside of the internal wall). 30 In a preferred embodiment the inflow chamber is located above the separation chamber, so that water entering the inflow chamber through the opening can drop into the separation chamber. The inflow chamber is preferably located substantially centrally of the separator tank. 35 The bypass weir preferably comprises two weir walls located between the inlet and the opening over which water can flow into the bypass passage. In one form the bypass weir 2 WO 2014/146178 PCT/AU2014/050005 creates a bridged channel between the inlet and internal wall opening. The floor of the bridged channel, also referred to as the inlet port floor, may extend to protrude into the inflow chamber and a baffle could be mounted at the end of the port floor. 5 In a preferred embodiment, a space adjacent the bypass passage defines a part of the outflow passage through which water rising from the separation chamber flows to the outlet. The space can be located between the bypass passage and an internal wall of the separator tank, or alternatively between the bypass passage and the internal wall. 10 A rim weir on the bypass passage can be provided to form a channel in which water flows to the outlet. The rim weir contains a notch through which rising water enters the bypass passage to exit through the outlet. In one embodiment the channel extends around the internal wall, and in the embodiment where the internal wall is closed, ie. forms an enclosure, the channel extends from near the inlet around both sides of the enclosure and 15 joins at the outlet. In an embodiment, the filter is a screen located below the bypass passage and above a floor of the tank to filter all water passing from the separation chamber to the outlet. The screen in one aspect is a downwardly depending screen extending substantially the height between 20 the underside of the bypass passage and the tank floor. In another aspect, the screen is more horizontally orientated than vertically to provide screening of water flowing out of the separation chamber. The filter may comprise an array of spaced parallel wires or bars. An upper portion of the inflow chamber can be closed off with a grate that prevents solids 25 escaping up through the upper portion of the inflow chamber, particularly during high water flows. Alternatively or additionally, the top of the inflow chamber can be made lower than an internal height of the separator tank so that in very high flows water can pass over the top of the inflow chamber. 30 Brief Description of the Drawings Embodiments incorporating all aspects of the invention will now be described by way of example only with reference to the accompanying drawings in which: 35 Figure 1 is an isometric view of a first embodiment of the solids separator in accordance with the invention; 3 WO 2014/146178 PCT/AU2014/050005 Figure 2 is an isometric view of the solids separator illustrated in Figure 1 with an outer casing removed; Figure 3 is an isometric view of an inner insert of the solids separator of Figure 1; 5 Figure 4 is a plan view of the solids separator; Figure 5 is a side sectional view taken at section E-E of Figure 4; 10 Figure 6 is a side sectional view taken at section F-F of Figure 5; Figure 7 is a plan view of the inner insert illustrated in Figure 3; Figure 8 is side elevation of the inner insert of Figure 3 viewed in the direction of Arrow A of 15 Figure 7; Figure 9 is a side elevation of the inner insert of Figure 3 viewed in the direction of Arrow B of Figure 7; 20 Figure 10 is a plan sectional schematic view of a second embodiment of a solids separator illustrating water flow denoted by arrows; Figure 11 front sectional view of the solids separator taken at section C-C of Figure 10 and illustrating a maximum treatable flow through the solids separator; 25 Figure 12 is a side sectional view of the solids separator taken at section D-D of Figure 10 and illustrating a maximum treatable flow through the solids separator; Figure 13 is a view similar to Figure 12 but illustrating a greater than maximum treatable flow 30 through the solids separator; Figure 14 is a view similar to Figure 12 but illustrating very high inflow through the solids separator; and 35 Figure 15 is an isometric view of the insert of a third embodiment of the solids separator; Figure 16 is a front sectional view of the third embodiment of the solids separator; and 4 WO 2014/146178 PCT/AU2014/050005 Figure 17 is a side sectional view of the third embodiments of the solids separator. Detailed Description of Embodiments 5 Figure 1 illustrates a solids separator 10 that is adapted to be installed (generally underground) towards the downstream end of drainage pipelines, usually in urban or industrial areas, to remove pollutants entering drains and to minimise the amount of pollutant (gross pollutants or fine materials) entering waterways and other exit points for pipeline 10 drains. While figure 1 illustrates the complete separator with an outer housing 11, cover 13 and storage zone 12, figure 2 illustrates the separator 10 without storage zone 12 and with cover 13 removed. Figure 3 illustrates an insert 15 that is positioned to sit inside the outer housing 11. 15 The solids separator illustrated in the drawings and described herein has been termed a "universal separator" as its features make the separator suitable for installation alongside all sizes of pipelines installed on slopes from mild to steep. The solids separator is capable of reducing energy losses in water flowing through multiple grades of pipes and steepness, that in turn reduces the problem of back flooding upstream. 20 Reduction of energy losses in the water flow entering the separator is achieved by the separator 10 having a separator tank 17 in which is located a separation chamber 19 and a filter 20 that filters solids entrained in water flowing into the separator tank through an inflow passage 22 so that water exiting the tank through an outflow passage 23 is free of solids. 25 There is also a bypass passage 25 along which water entrained with solids entering the separator tank 17 through an inlet 27 can bypass the separation chamber 19, for example during high flood events, to exit an outlet 28 of the separator tank. While the bypassed water may still be entrained with some solids the bypass feature prevents a bottle neck of water 30 forming at the solids separator during high flood events and therefore reduces surging back upstream and flooding of urban or industrial areas. The cross-sectional views of figures 5 and 6 and the plan view of figure 4 illustrate the water flow passages through the separator 10. Figures 1 to 9 illustrate one embodiment of the 35 solids separator 10 which is specifically a cylindrical or round version of the separator, while figures 10 to 14 illustrate schematically a square version of the solids separator 10. Figures 5 WO 2014/146178 PCT/AU2014/050005 15 to 17 illustrate a third embodiment of the solids separator, which is a modification on the round version. While all versions differ somewhat in their finer features and shape, all versions contain the 5 main features of the solid separator described above. Furthermore figures 10 to 14 usefully illustrate the flow path of water with the aid of arrows. Similar features found in both embodiments are denoted the same reference number in order to maintain clarity. The solids separator 10 also contains an inflow chamber 30, which forms part of the inflow 10 passage 22 of water flowing into the separator tank 17. The inflow chamber 30 in the flow passage 22 is partitioned from the bypass passage 25 by an internal wall 32 where the internal wall 32 has an opening 33 that is located near the tank inlet 27 to allow water flowing into the separator 10 to first flow through inlet 27 of tank 17 and continue forward to flow through the internal wall opening 33 into inflow chamber 30 from where water will flow 15 into the separation chamber 19. From figure 3 it can be seen that the insert 15 can be formed as unitary piece comprising the inflow chamber 30 defined by an internal annular wall 32 and the bypass passage 25. Figures 7, 8 and 9 also illustrate the insert 15 from different angles. Internal wall 32 is 20 closed to the bypass passage aside from opening 33 that aligns with the inlet 27. The opening 33 and inlet 27 are aligned in the direction of water flow so that water flowing through the pipeline and into the solid separator 10 flows directly through the opening in the internal wall and into the inflow chamber 30. Once it has entered the inflow chamber 30, 25 water enters the separation chamber 19, which is located directed underneath the inflow chamber 30, and solids collect on a floor 21 of the separation chamber 19. Bypass passage 25 is defined by a floor or channel in the insert 15 that provides a surface or platform along which water can flow from the inlet 27 to the outlet 28 thereby bypassing 30 the separation chamber located below the bypass passage. The bypass passage is separated from the inflow chamber 30 and follows a path around the internal wall 32 to carry water from the inlet directly to the outlet. The bypass passage contains a rim weir 38 along at least one side edge of the bypass 35 passage floor in order to create a channel for containing and guiding water in the bypass passage, whether that water is clean water rising up from the separation chamber or water bypassing the separation chamber, to the outlet. A notch 40 in the rim weir 38, that can be 6 WO 2014/146178 PCT/AU2014/050005 V-shaped, permits low trickle flows to enter the bypass passage (acting as a return passage) from the separation chamber 19 and exit through the tank outlet 28, thus draining the upstream pipeline. The rim weir 38 in this embodiment is designed to have a height of about one-tenth to one-fifth of the diameter of the upstream pipe. 5 In both embodiments illustrated (referring specifically to figures 4 and 10) the bypass passages 25 extend around the inflow chambers 30 so that excess water from high flows can be carried directly to the outlet 28 by the shortest route. Having two bypass passages in the separator with each extending on either side of the inflow chamber 30 is advantageous 10 because should one of the bypass passages become blocked, water can still flow through the other passage. In some cases of very high flows excess water can even be designed to flow over the top of the inflow chamber 30. A bypass means 42 is provided at the inlet 27 of the separator, which is specifically in the 15 form of two bypass weirs that extends between the inlet 27 and opening 33, and on either side of the inlet port floor 44 to define a bridged inflow channel through which incoming water is guided to flow into the inflow chamber 30. While the drawings illustrate two weir walls 43 extending on either side of an inlet port floor 44, it is understood that only one weir need be present to provide a bypass function. 20 The height of the bypass weirs 43 is sufficient to contain inflow of water during low to moderate events but during high flow events in which the solid separator reaches its maximum filtering capacity the bypass weir is designed to allow inflowing water to flow over the bypass weirs and directly into the bypass channel and to the outlet thereby bypassing 25 the separation chamber 19. The bypass weirs 43 are greater in height than the rim weir 38 on the bypass channel so that, during normal low to moderate flows, water is encouraged to follow the desired filtration path (i.e. inflow passage and then outflow passage) whereby water enters the inflow 30 chamber, drops into the separation chamber, filters through filter 20 and rises up on the outside of the separation chamber (between an inside wall 18 of the outer housing 11 and the separation chamber 19) and rises up to flow through notch 40 (or in higher flows directly over the rim weir 38) into bypass passage 25 and out of the solid separator through outlet 28. Accordingly, bypass passage 25 also acts as a return passage for carrying filtered water 35 to the outlet 28. 7 WO 2014/146178 PCT/AU2014/050005 Rather than filtered water rising up between the inside wall 18 of the housing 11 and the bypass passage, it is understood that a gap (not shown) for allowing access to outflowing water could instead be located between the bypass passage 25 and internal wall 32. 5 The bypass weirs 43 create a bridged channel between the inlet 27 and internal wall opening 33 which defines the inlet port floor 44. The inlet port floor may terminate at the entrance of the opening 33 as illustrated in figure 3, or may protrude a little further into the inflow chamber 30 as illustrated in figure 10. 10 Internal wall 32 defining inflow chamber 30 is located adjacent the bypass passage 25 and in the drawings the internal wall is illustrated positioned directly adjacent the bypass passage 25, although it could instead be separated from the bypass passage by a gap running alongside the internal wall 32. 15 As illustrated in the side elevation figures of both embodiments the internal wall 32 extends to a height above the bypass passage and namely, the internal wall has a height that measures from the bypass passage floor to a height above the bypass weir. The height of the internal wall is sufficient to define the internal inflow chamber 30 into which water flowing at any speed (from slow flow to surging flow) can enter and flow into the separation chamber 20 without being obstructed or hindered at the inlet of the tank, which will cause a hydraulic jump in the water flow which in turn can cause upstream surges and flooding. In the embodiments illustrated the internal wall 32 is a substantially vertical wall forming an enclosure inside which is the inflow chamber. However, the internal wall need not be 25 vertical but could be inclined to some extent or domed, so long as it provides a partition between an inflow chamber and the bypass passage. Below the level of the bypass passage 25 inflow chamber 30 opens into the separation chamber 19 and the embodiment illustrated in figures 5 and 6 show an annular skirt 35 30 substantially in line and of similar dimensions to the internal wall 32 depending in a direction downwardly of the bypass passage 25. The skirt 35 directs incoming water into the separation chamber 19. The filter 20, which in the embodiments illustrated is a series or array of parallel spaced 35 wires or bars forming a screen around the annular skirt 35 and define the separation chamber 19 in which solids and other small or large particles are filtered by the filter 20 and retained in the storage zone 12 until they are cleaned during a maintenance visit. 8 WO 2014/146178 PCT/AU2014/050005 It can be seen in the embodiment of figures 10 to 14 that a similar skirt 36 to annular skirt 35 is provided except that skirt 36 is a square skirt that follows the square concentric shapes of the outer housing 11 and inflow chamber 30 and rather than the filter 20 being disposed 5 around the square skirt, the filter 20 instead is attached to a lower end of the square skirt 36 to provide the screened area of the separation chamber 19. Water flowing through filter 20 to the other side of the separation chamber 19 is clean of solids. As the water level in the separator tank rises due to rain the water level of the clean 10 water in the tank will rise up through an up-flow channel 34 on the outside of the filter screen (with water entrained with solids still rising up on the inside of the filter). When the water level reaches the height of the bypass passage 25 the clean water enters the bypass passage, firstly through notch 40 in the rim weir 38 to flow along the bypass passage and exit through the outlet 28. 15 The described inflow passage of water to the separation chamber and outflow passage from the separation chamber is the path water flowing into the solid separator is designed take during low to moderate flows and up to the separator's maximum treatable flow. Where the flow of incoming water is greater than the maximum treatable flow, which is usually a one in one year event but depends on the size of the separator relative to the water capacity and 20 steepness of the incoming pipeline, some of the water will bypass the separation chamber and flow directly to the outlet. In order to minimise solids flowing back upstream from the inflow chamber and to limit the amount of inflowing water into the inflow chamber 30, a part of the internal wall 32 above the 25 wall opening 33 forms a baffle 46. Baffle 46 provides a type of header over the wall opening 33 to create an upper space 48 in the inflow chamber 30 that is higher than the highest part of the opening 33. This means that during high flows when the water in the tank rises to a point higher than the incoming pipe line 55, the upper space 48 in the inflow chamber acts to retain floating and fine buoyant material as well as oils and scum preventing them from 30 floating back upstream. To contain floating materials in the upper space 48 a water permeable grate or screen 50, such as a mesh screen or other kind of filter, covers the top or top sides (as illustrated in Figures 13 and 14) of the inflow chamber 30. Instead of forming part of the internal wall over the opening, a baffle 46 could be provided 35 separately across an upper part of the opening in order to have the same affect of minimizing solids flowing back upstream. The baffle could be provided on the same side of the internal wall as the inlet, namely on the outside of the internal wall, or the baffle could be 9 WO 2014/146178 PCT/AU2014/050005 provided on the other side of the internal wall, namely on the inside in the inflow chamber 30. The baffle 46 in wall 32 acts to limit the flow entering inflow chamber 30 by throttling the inflow causing excess water during high flows to bypass the inflow chamber via bypass weirs 43. When also provided in the inflow chamber the baffle 46 also acts to dampen the 5 inflow energy carried by the water. Alternatively, a baffle could be provided at the end of the inlet floor in the embodiment where it protrudes into the inflow chamber. For example, Figure 10 illustrates an inlet port floor 44 protruding into the inflow chamber 30 at the end of which a baffle could be attached. This 10 would have the effect of not only reducing the solids escaping back upstream in high flows, but also slowing down the inflowing water so as to not disturb the solids collected in the separation chamber 19. Figures 11 to 14 illustrate different modes of operation based in the flow rate of water flowing 15 into the solids separator 10. The front section view of Figure 11 and side section view of Figure 12 illustrate the operation of the solids separator during maximum treatable inflows which will occur about once a year. Water entrained with solids, s, enters the solids separator 10 through inlet 27 and, contained 20 by bypass weir 42, flows into the inflow chamber 30 where grit, heavy litter and particular matter sink to the floor 21 of the separation chamber 19 while buoyant pollutants rise to the surface. In this mode of operation the inflowing water sinks in the separation chamber 19 to pass under the lower edge of skirt 36 and through the filter 20 that acts as a retention screen for the solids. The water then flows upwards in the up-flow channel 34 and passes into the 25 bypass passage 25 and through to the outlet 28. In this embodiment, the bypass passage 25 with rim weir 38 forms a channel in the bypass passage, and is also provided with a downwardly depending channel wall 52 that is mounted from an upper end to depend downwardly terminating shortly above the rim weir 38 to form a 30 gap 53 through which outflowing water flows to the outlet. The V notches can still be provided in the rim weir in this embodiment. Figure 13 illustrates a second mode of operation where the inflow of water into the solids separator 10 is higher than that illustrated in Figures 11 and 12 and exceeds the capacity of 35 treatable flow in the separator. In this mode of operation the water level has risen in the separation chamber 19 as a result of water rising in the upstream pipeline 55. Accordingly, the water level is higher than the crest of the bypass weirs 43 and therefore allows excess 10 WO 2014/146178 PCT/AU2014/050005 flow to passes over the weirs 43 and into the bypass passage 25 that flows directly to the outlet 28. No treatment of this excess flow takes place although the maximum treatable flow can still be treated. 5 Figure 14 illustrates a third mode of operation that occurs during very high inflows wherein the upstream pipeline 55 flows full, which occurs once every two to five years, depending on the grade and design of the pipeline. During such inflows the combined capacities of the orifice 53 and bypass weirs 43 are exceeded so that the water level rises to the top of the inflow chamber 30. When this water level is reached, the rising water in the inflow chamber 10 30 spills out through the screen 50 and into the bypass passage 25 and then into the outlet 28. The screen at the top of the inflow chamber retains large floating matter that allows escape of fine buoyant material together with oils and scum. In this high flow event surging inflowing water is also designed to pass right over the top of 15 the internal wall 32 and the inflow chamber 30 and close to an upper end of the tank 17 to exit the outlet. Accordingly, the height of the inflow chamber 30 can be selected with this function in mind, namely a lower height will allow more surging water in high flow events to flow through the separator without creating blockage and back-flooding. 20 In a further embodiment of the invention the top of the inflow chamber is lowered and enclosed so that super-critical inflows exceeding the design treatment flow pass over the inflow chamber to the outlet port without passing through a hydraulic jump. Figures 15, 16 and 17 illustrate a third embodiment of the solids separator 10 which is 25 similar in features to the first round embodiment but is modified in several ways. Firstly an outlet invert 62 at the outlet 28 is lower than an inlet invert 64. Furthermore the outlet 28 is conical in shape tapering in the flow direction from an enlarged end to a narrowed end. In one example, the enlarged end of the conical outlet 28 can be 30 approximately 40% larger than a diameter of the inlet 27. These modifications to the enlarged outlet 28 contribute to assisting high energy flows to enter the downstream pipe with minimum energy loss, and in many cases to flow/bypass through the separator minimizing the instance of a hydraulic jump. The tapered outlet can assist in slowing high energy flows. 35 11 WO 2014/146178 PCT/AU2014/050005 This embodiment is suited to installing with pipelines having a steep grade where the difference in height between outlet invert and inlet invert allows for internal losses in the separator. 5 The bypass weirs 43 in Figures 15 to 17 are higher than in the first embodiment and in this example are approximately % height of the inlet diameter. Furthermore, the inlet port floor 44 is higher than the bypass passage 25. In the third embodiment there is also provided a further chamber baffle in the form of an 10 angled screen 60 located in the inflow chamber 30 and angled (450) downwardly facing the opening 33. The screen acts to further help dampen or suppress the energy in the inflowing water in addition to the affect of the inflow chamber 30 has to slow down the flow, and in addition or instead of an internal baffle. The screen 60 is located on a wall opposite to the inflow chamber opening 33. 15 The design of the described solids separator addresses problems of internal energy losses that can occur through hydraulic jumps in solids separators as a result of high flows into the separator or steep grades of pipelines leading to the separator being suddenly stopped, which can cause a problem of upstream surges and flooding. The features of the solids 20 separator have the effect of minimizing the upstream progression of a hydraulic jump which means that the solids separator is suitable for installation on both mild and steep pipelines, and all grades in between. The current solids separator is capable of processing a large variety of flows from low sub-critical flows to high super-critical flows and can be retrofitted to pipelines of all grades making the separator widely applicable to many installation 25 environments. Even though two examples of the solids separator have been illustrated, there are a number of modifications to the design of the solids separator that could achieve the purpose and advantages of the separator. Modifications could be made to the positioning and nature of 30 the filter 20 in the outflow passage. A number of different water permeable filter means could be used such as square mesh screens, perforated sheets or the parallel wires described herein. The wires/screen could be provided along the entire height of the separation chamber from 35 the floor 21 of the chamber to the underside of the bypass passage 25 as illustrated in Figures 5 and Figures 6. Alternatively, as illustrated in Figures 11 to 14, the filter may be applied to a small area at a lower end of the separation chamber. Further alternatives could 12 WO 2014/146178 PCT/AU2014/050005 include the filter screens being not necessarily positioned vertically with respect to the solids separator, but inclined at an angle or positioned horizontally across the up flow channel 34. To inspect and maintain the solids separator an access hatch 57 can be provided at the top 5 of the housing 11 (Figures 11 to 14) or the entire cover 13 covering the top of the outer housing 11 is removable as illustrated in Figures 1 and 2. The access hatch 57, or another top portion of the separator, may also have a grate to allow water to escape through the grate during very high flows and thereby minimize upstream flooding. 10 It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word 15 "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 13

Claims (19)

1. A solids separator comprising: a separator tank having an inlet and an outlet through which water entrained 5 with solids can flow; an inflow passage from the inlet to a separation chamber in the tank, and an outflow passage from the separation chamber to the outlet with a solids filter located therein; a bypass passage accessed over a bypass weir that allows water to flow from 10 the inlet to the outlet bypassing the separation chamber; and an internal wall in the separator tank that partitions an inflow chamber from the bypass passage wherein the internal wall has an opening located near the separator's inlet, and the inflow chamber and opening are located in the inflow passage. 15

2. The solids separator according to claim 1, wherein the internal wall forms an enclosure in the separator tank defining the inflow chamber.

3. The solids separator according to claim 1 or claim 2, wherein the internal wall is 20 located adjacent the bypass passage.

4. The solids separator according to any one of the preceding claims, wherein the internal wall extends to a height above the bypass passage. 25

5. The solids separator according to any one of the preceding claims, wherein the opening and inlet are aligned with each other in the direction of water flow.

6. The solids separator according to any one of the preceding claims, wherein a part of the internal wall above the opening forms a baffle to minimise solids flowing back 30 upstream of the opening.

7. The solids separator according to any one of claim 1 to 5, wherein a baffle is provided across a part of the opening, in front of or behind it, to minimize solids flowing back upstream of the opening. 35

8. The solids separator according to any one of the preceding claims, wherein the inflow chamber is located above the separation chamber. 14 WO 2014/146178 PCT/AU2014/050005

9. The solids separator according to any one of the preceding claims, wherein the bypass weir comprises two weir walls located between the inlet and the opening over which water can flow into the bypass passage. 5

10. The solids separator according to any one of the preceding claims, wherein a space adjacent the bypass passage defines a part of the outflow passage through which water rising from the separation chamber flows to the outlet.

11. The solids separator according to claim 10, wherein the space is part of an up-flow 10 channel located between the bypass passage and an internal wall of the separator tank.

12. The solids separator according to claim 10 or 11, wherein a rim weir on the bypass passage forms a channel in which water flows. 15

13. The solids separator according to claim 12, wherein the rim weir contains a notch through which rising water enters the bypass passage to exit through the outlet.

14. The solids separator according to claim 12, wherein the channel extends around 20 the internal wall.

15. The solids separator according to any one of the preceding claims, wherein the filter is a screen located below the bypass passage and above a floor of the tank to filter all water passing from the separation chamber to the outlet. 25

16. The solids separator according to claim 15, wherein the screen is a downwardly depending screen extending substantially the height between the underside of the bypass passage and the tank floor. 30

17. The solids separator according to any one of the preceding claims wherein the filter comprises an array of spaced parallel wires or bars.

18. The solids separator according to any one of the preceding claims, wherein the internal wall defines an annular inflow chamber. 35

19. The solids separator according to any one of the preceding claims, wherein an upper portion of the inflow chamber is closed off with a grate that prevents solids escaping the upper portion of the inflow chamber. 15