AU728181B2 - An apparatus for the separation of solids from flowing liquids - Google Patents

Description

P/00/01i1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: An apparatus for the separation of solids from flowing liquids The following statement is a full description of this invention, including the best method of performing it known to us: FHPMELC6981 38003.6 1 AN APPARATUS FOR THE SEPARATION OF SOLIDS FROM FLOWING LIQUID This invention relates to methods of and apparatus for separating floating and suspended solids from a flowing liquid using continuous deflective separation, and particularly, but not solely non-mechanical methods and apparatus.

There are many applications where it is desirable to separate solids from a flowing liquid including: 1. Separation of solids from stormwater.

In many areas of Australia, and in countries other than Australia, stormwater is directed to waterways and seas.

Stormwater is a major carrier of solid pollutants such as plastics, cans, tree branches and animal faeces, amongst others to waterways and seas.

Endeavours have been made to limit the passage- of at least some of these materials. One method used is by having grates *across outlets from the drains but these have generally been unsatisfactory because the size of the grate must be such as to enable water to pass even if material is held against the grate by water pressure so it has been necessary that the grate be of substantial opening size. Also, even such grates S can be blocked and it is essential to provide a flow path 2 around or over the grate to prevent build up of water upstream in the drain system. A second alternative proposed has been the use of systems, such as cyclones and dynamic separators, to remove the waste. Whilst these can be efficient, they are too expensive to be used in the whole of a stormwater system.

2. Separation of liquid from sewage.

A major difficulty with many sewage plants is the sheer volume of liquid to be handled. This is aggravated where a "mixed" system, that is a system which carries both sewage and storm water is used. In many cases, sewage plants could handle more sewage if the quantity of liquid delivered therewith could be reduced, if, for example, liquid was removed from sewage before is enters trunk sewers. This has not been considered feasible.

Also, there are regions where stormwater and sewage are received by the same system. This can cause difficulties where there are heavy rains which overload the system as it is undesirable to permit raw sewage to pass to overflow.

3. Removal of pollutants from industrial wastes.

o Many industrial plants must pay prohibitive rates to discharge polluted liquids into sewers. It would be most desirable to separate a part of the pollution before the waste is delivered to sewers and this would provide economies both to the plant and to the authority if this cost of the early removal of polluted matter was less than the cost of cleaning up pollution later.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

Summary of the Invention I0 There is disclosed herein an apparatus that separates solid matter from a liquid stream passing through the apparatus along a predetermined path, said apparatus including a separation panel located on said path and having a face over which the liquid passes in a predetermined direction, the panel having a plurality of apertures through which solid matter of a size larger than a predetermined size cannot pass, said apertures being located at positions spaced both in said predetermined direction as well as generally *transversely of said direction, and wherein said panel has protruding solid segments o• associated with the apertures which shield the apertures with respect to liquid passing the panel by forming a substantially closed face to the liquid passing in said direction.

e• Preferably the separation panel of the above apparatus is expanded metal mesh.

Preferably the apertures in the above mentioned separation panel face in a direction which has a direction component in said predetermined direction.

•o o* .i [R:\LIBAA]08197.doc:lzg 4 In order that the invention may be more readily understood, reference will be made to the accompanying drawings, which show certain examples of the invention.

In the drawings: Figure 1 is a plan view through one example of separator made in accordance with the invention; Figure 2 is a vertical section along line a-a of Figure 1; Figure 3 is a vertical section along line b-b of Figure 1; Figure 4 is a view along arrow of Figure 1; Figure 5 shows a vertical section through a second example of a separator according to this invention; Figure 6 shows an enlarged detail of the vertical section through the separation panel; Figure 7 shows an example of an installation in a channel or river of separation panels for the removal of solids from a flowing liquid and subsequent collection and a oooo *g o** *co g* *ooo* *o o*o• o* *g o*O *o [R:\LIBTT]08200.doc:zg JU. UU1i.ZeUUU IZ:UZ FRKU6UN AND iMUbU blH9Zblb4db NU. l'/bb F. 4 storage; Figure 8 Figure 9 9

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Figure 10 Figure 11 Figure 12 shows an enlarged section a-a through the holding chambers; shows as enlarged horizontal section through the separation panel; shows an enlarged elevation of the separation panel viewed in the direction of flow of the channel in Figure 9 at view "10" with the openings substantially closed to view; shows an enlarged elevation of the separation panel from the angle giving maximum open space, in Figure 9 at view "I1"; shows a side elevation view of a system which can remove water from sewage whilst permitting the solid matter to proceed, and is a view along line 12-12 of Figure 13; Figure 13 shows a plan view of the system of Figure 12; Figure 14 is a view along line 14-14 of Figure 13; Figure 15 is a view along line 15-15 of Figure 13; 30/10 '00 MON 11:53 [TX/RX NO 6570] MI. OCT. 2000 12:02 SPRUSON AND FERGUSON 51292515486 NO, 1756 P, 0 a a a a Figure 16 Figure 17 Figure 1s Figure 19 Figure 20 shows a cylinder driven mechan.ically in a direction opposed to the protruding deflective segments of the separation apparatus causing deflection of particulant matter away form the device while allowing liquid to pass through via the openings; shows a mechanically driven apparatus with internal deflective segments and openings; shows a longitudinal:- vertical section through a further emtbodiment of the invention; shows an enlarged detail of the section through the lower separation panel of Figure 18; shows a longitudinal vertical section through another example of this invention which has a water filled solids collection sump; shows an enlarged detail of the section through the upper separation panel of Figure shows a plan view of an arrangement using a separation plate of the invention, together with a dynamic separator whereby the volume of water relative to solid material can be restricted; and Figure 21 Figure 22 30/10 '00 MON 11:53 [TX/RX NO 6570] JU. U'r. ZUUU IZ:U Z SRUSON AND PXUUN bIZY9ZIb4db NO. I'/b P.

7 Figure 23 shows a section along line 23-23 of Figure 22.

Referring first to Figures 1 to 4 we illustrate an apparatus which is a gross pollutant trap placed in line in, say, a stormwater drain.

Before describing this in detail, the invention is equally boo. applicable to major applications, such as in open channels, feeders or trunk stormwater drains or can be used in smaller applications such as in car parks. In the first type of oapplication, the apparatus can be cast in situ or could be fabricated from pre-cast components, in the second could be of a pre-cast construction.

le The type of apparatus illustrated in Figures 1 to 4 can be considered a larger construction and, in this case, the apparatus can be retro-fitted into a stormwater system and preferably in an area which gies reasonable access.

The apparatus has a containment sump 10 which, as shown, is contiguous with a separation chamber 16. The sup i0 is located beside the original position of the stormwater drain, which is broken to provide an inlet 11 into and an outlet 12 from the separation chamber. As the sump has to be cleaned at intervals, the size of the sump is such as to give a required interval between cleaning and to allow recirculation of liquid 30/10 '00 MON 11:53 [TX/RX NO 6570] .JU. DCI', ZUUU 12 UZ SFRUSUN AND MRCUUN bI~Ub~b4Ub N, 1/bb P. 'I 8 into the separation chamber- im can vary in form and dimensions to suit specific site and project requir ements.

The separation chamber has the separation panel 13 which is preferably a stainless steel plate, as will be described hereinafter, and which acts to separate the inlet 11 from the outlet 12. Parallel to the separation panel there may be a containment and flow direction baffle 14 which can be basically parallel to and spaced from the separation panel.

This baffle 14 must be arranged to allow recirculation and may preferably extend from the top of the chamber to 'contain floatables and to below the bottom of the separation* plate to permit recirculation.

A high level baffle 15 can be provided to retaini floatables during extreme conditions.

:9 As illustrated, the separation panel 13 is perforated but is 9 formed so that it presents to the incoming liquid a closed face. As can be seen from Ficlre 6, the panel can. be deformed so that there are a number of surfaces 20 which are directed towards the flow and which have therebehind a number of apertures 21, which pass through the panel. A formation-such as this is possessed by expanded mesh.

There are other ways in wbich the separation panel may be formed, including the use of a series of bars or f lat rods 30/10 '00 MON 11:53 [TX/RX NO 6570] XuU~I. Uuu iz:uz bfKUbUN AM) VtX~jUbUP 0IZUi~4b MU, 1/bb F. d 9 which are located to provide a closed face 'to the flow but with apertures located behind and between these.it is preferred, in this and the other embodiments to be described that the closed face, as a whole, presents a positive angle to the flow of liquid. The preferred angle will vary with different applications of the invention and. can be close to being directly across the flow to being sutantially parallel to the flow.

::On liquid entering through the inlet, the sumnp 2.0 is f irst ::ffilled and then the liquid is then caused to move along the separation panel 13, and is constrained to this movement by the containment and flow direction baffle 14.

As there is effectively an hydraulic head between the inlet 11 and the outlet 12, whilst there will be movement of the liquid and any entrained solid material along the panel 13, there will be movement of liquid through the apertures 21,' to the outlet 12. The solid material will, if it strikes the panel, tend to move along the panel by the forward momentum of the liquid and down the panel, by gravity. Should solid material larger than the apertures -strike the surface, the forward movem~ent of the liquid provides a self-cleaning of the surface of the panel so there is little or no tendency for blockage.

The apparatus can thus be left for substantial periods with confidence that the panel will not become blocked, it ohly be 30/10 '00 MON 11:53 [TX/RX NO 6570] JU, UUU iz:UJ bfYUUN ANU tM MUUN blYUblb4bb NU, I'b U necessary that the sump is cleaned at intervals before it is over-filled with solid material.

Because of the form of movement, we have found the arrangement such that not only is all solid material larger than the apertures in the panel retained, but much that is smaller.

The sold material is carried through to the sump where it tends to drop under gravity and whilst some material, particularly light material, can be moved past the separation panel more than once. The liquid which enters the sump tends to move in an arcuate manner and most of the material falls into the sump after its first movement therethrough and before it is again passed along the face of the separation panel.

Floatables will also be held in the sump. However if upstream "control of floatables, say by the provision of similar apparatus at major sources such as take away food outlet carparks, is good, there may not be great quantities of floatables to be retained.

In order to maintain the apparatus, it is only necessary to empty the sump 10 at intervals to prevent excessive build up of solid matter in the sump.

Under extreme conditions, say flood or near flood conditions, it will be seen that the apparatus of the invention will not 30/10 '00 MON 11:53 [TX/RX NO 6570] JU. UU. EUUU IJ:UJ bfKUbUN AND VtKbUbU blZ Zblb4db NU. i'bb F. 1U 11 act as a source of difficulties. The apparatus can be so designed as to carry as much liquid as the inlet stormwater drain.

If, say because of poor maintenance and the build up of solid in the sump, an overflow can be provided over the top of the separation plate. For these conditions, we provide the high level baffle 15 which extends from just below the top of the separation plate to the top of the flow diverter baffle and acts to retain floatables.

R eferring now to Figures 5 and 6, we illustrate a simple construction which utilises the invention and can be used in open channels or the like.

The liquid containing suspended and floating solids enters through inlet 24 into the separation chamber 23. The chamber is divided into inlet and outlet sides by a separation panel 22 fixed at the lower edge to the outlet side of the. chamber 23, and inclined at an angle towards the inlet 24. Again the panel 22 presents a closed surface to the incoming liquid but, as described in relation to the previous embodiment, liquid can pass through the panel 22 and to the outlet The panel 22, the sides of the inlet 24 and the inlet sides of the chamber 23 extend to a height above surface sufficient to prevent any floating solids from crossing over to the outlet 30/10 '00 MON 11:53 [TX/RX NO 6570] JU. CT. ZUUU 12:U3 SPRUSON AND E USUN b'lZ Zblb4Bb NO, '16b P. 11 12 side of the chamber 23.

The panel 22 can be skewed to one side to aid the movement of floatable materials off to the side and away from the panel.

Again, as previously discussed, the separation panel 22 is constructed with a series of segments 20 which are angled when the panel is in its required orientation and thus provide a substantially solid face opposing the liquid flow and a corresponding series of substantially horizontal openings 21 that allow the liquid to pass up and through the panel 22 to the outlet side of the chamber 23 and thence to the outlet o* 'The substantially horizontal orientation of the openings 21 in the panel 22, combined with the general downward liquid flow over the inlet side of the panel, discourages clogging and blocking of the openings by the suspended solids. A large portion of the kinetic energy of the suspended solids is dissipated as they are deflected and forced down at the panel causing them to settle down to the collection sump 26 at the bottom of the chamber 23. These solids can also be caused to move to the side as well as down.

The collected solids are removed periodically by manual or mechanical means.

Referring now to the embodiment of Figures 7 to 11. This 30/10 '00 MON 11:53 [TX/RX NO 6570] OC1. 20U 12:03 SPRUSON AND FERGUSON 61Z02b1b486 NO. 17bb P. 12 13 embodiment shows use of the invention as a boom or the like extending across a waterway or channel. The separation panel 31, which can be in one piece or made up of overlapping segments, is placed in the flowing liquid at an angle so as to deflect suspended and floating solids to the side collection chamber 32. The panel 31 preferable extends far enough below surface level to catch floating and near-surface suspended solids; It can, in the case of a channel or river installation as shown in Figure 6, be supported by a tensioned :cable 33 anchored to the bank 34 at one end and to a .*substantial pylon 35 set in the channel, at the other end. It *may be continuous across the width of the river or as shown in Figure 6 only project part way across, being placed at a strategic location near a bend to xnaximise the amount of solids caught.

The collection chamber 32 has an opening 36 to the channel which although normally being open, is periodically closed by a mechanical operated door 37 to prevet further ingress of liquid and solids. When this door 37 is closed, the mechanically operated door 38 to the stockpiling chamber 39 is opened, allowing all the liquid and solids from the collection chamber 32 to enter. When the collection chamber 32 is empty, the door 38 to the stockpiling chamber 39 is closed and the door 37 to the channel is opened again allowing ingress of liquid and solids to the collection chamber 32.

30/10 '00 MON 11:53 [TX/RX NO 6570] AU UUI. ZUUU I1Z: U4 S1HUMU AVV PEXHMUD b1lUblb4bb NU. 1lbb 14 The stockpiling chamber 39 contains a removable b~asket 40 open at the top made of similar material to the separation panel, thus allowing the liquid to pass through the basket to the lower part 41 of the stockpiling chamber from whence it is removed and discharged to the channel by mechanical means such as a pump 42. Solids are retained in the basket 40 which can be ztemoved and emptied periodically. Both chambers are covered by removable lids The separation panel 31 in this example is an expanded metal stainless steel plate placed in a substantially vertical plane *and angled to the direction of f low so that the solid segments 43, Figure 9, form a substantially closed f ace when viewed *from the direction of flow causing solids to be deflected along the direction of the panel 31. The liquid passes freely through the openings 44, Figure l1, in the panel and continues, unimpeded by the panel 31, in the flow.

Figures 12 to 15 show a system whereby liquid can be. removed from sewage so that the sewage, together with enough liquid to act as an effective carrier thereof can be passed to a main sewer, possibly through a pumping station, and the liquid can be passed to a treatment plant whereby it can be treated either to a stage in which it can be used, f or example, for watering or even to a stage in which it become potable.

It will be appreciated that the capacity of sewers and 30/10 '00 MON 11:53 [TX/RX NO 65701 OCT. 2000 12:04 SPRUSON AND FERGUSON 6129251b486 NO. 1756 P. 14 treatment Planlts are limited by the amount of liquid passimg therethrough or thereinto. If the amount Of liquid can be restricted, this Will enable effectively greater capacities than would otherwise be the case.

Sewage is often passed through pumping stations and if there is to be separation of the liquid from the solid material, it :is necessary that such separation occurs before any pumping which tends to homogenlise the material.

The system of Figures 12 to 15 includes a channel 100 which carries the liquid/solid mixture and on one Bide of this there is a separation panel. 101 which can have the same properties of the panels described earlier herein.

On the side of the panel 101 away f rom the channel 100 there a liquid receiving area 102 which has an outer wall 103.

The outer wall 103 defines the volume of materi.al which can pass through the screen and the tapering shape aids in !the maintenance of similar' surface gradients on each side of the plate 101.

If the volume of flow is sufficient, it may be desirable to have separation panels on each side of the channel and the location of the other separation panel and its receiving area anid wall are illustrated in broken line in Figure 13.

30/10 '00 MON 11:53 [TX/RX NO 65701 3O. OCT. 2000 12:04 SPRUSON AND FERGUSON 61292515485 NO. 1756 P. 16 The outer wall has an outlet 104 which may be closed by gates 105 and 106. The gate ios effectively controls the head im the channel 100 as liquid will pass through the plate 101 and reach the level of the top of the gate 105 before any liquid is passed to the outlet 104. The gate 106 aids in the control of the size of the outlet and thus the characteristics of the f low. Specifically, this can control the effective head and thus ensures that the f low though the channel is such as to ensure tham the screen 101 is self cleaning.

Ref erring now to Figure 16, the apparatus 61 is placed in liquid 64 containing particulate matter and rotated as shown at 63 in a direction so as to produce relative movement and deflection by the protruding segments 68 while allowing liquid to pass through the surface 62 of the apparatus by way of the open igs 67. Liquid is removed from inside the cylinder 66.

The apparatus is rotated about its centre 6S.

It may be preferred that the liquid 64 is alSO be caused to move relative to the apparatus to obtain the best operation.

Referring to Figure 17, the apparatus 69 has a conical shape and rotated at its axis 70 at an angle downward showing the Openings 73 to be closed to a perpendicular view from the inside of the apparatus 69. Liquid containing particulate matter 74 enters at the smaller opening 77 and passes over the inside surface of the apparatus 78. The protruding deflective 30/10 '00 MON 11:53 [TX/RX NO 6570] OCT. 2000 12:04 SPRUSON AND FERGUSON 61292615486 NO, 1756 P. 16 17 segments 72 as shown in detail 71 cause particulate matter to pass down along the inside surface of the apparatus and exit at the larger opening 76 while liquid is able to pass around the deflective segments 72 through the openings 73 and downward away from the apparatus 75. This process is aided by its rotation 79.

Referring to Figures 18 to 21, we provide an apparatus which, whilst using the principle of the invention, highlights the effect of gravity on liquid movement through the separation panel.

In this embodiment, the liquid/solid mixture enters through the inlet 81 into the upper part of the inlet side of the separation chamber 95, passing over a substantially horizontal i spreader plate 82 to allow the flow from the restricted inlet 81 to spread out towards the sides of the chamber. It then passes over the direction plate 83 which is curved to further spread the flow to the width of the chamber and direct the flow towards the upper separation panel 84. The spreader plate 82 and the upper separation panel 84 are substantially tangential to the curved flow plate 83 at its top and bottom edges respectively.

In this example of the invention the separation panel 84 is made from expanded metal sheets. The openings 91 in the panel are individually in a substantially vertical plane while the 30/10 '00 MON 11:53 [TX/RX NO 6570] OCT. 2000 12:04 SPRUSON AND FERGUSON 61292615486 NO. 1756 P. 17 18 connecting solid segments 92 have a positive downward slope in the direction of flow. They form a series of small downwatrd sloping steps over which the larger solids are directed, by the action of gravity and force of the flowing liquid, to the solids collection sump 86 at the base of the panel 84. There may be a solids straight or curved transition panel 85 at the base of the separation panel 84 to aid in clearing the panel of certain types of solids.

The layer of liquid closest to .*the separation panel 84 is subject to pressure by the action of gravity and the pressure of the overlying blanket of liquid and at each step in the panel B4 a portion of the liquid passes through the openings 91 to drop to the outlet collection sumnps 89 below and thence to the outlet *see*: The solids collection sump 86 has on at least one side a backward sloping separation panel 87 fixed to the out-let side *of the sump 86. This lower separation panel 87, is -formed with a series of vertical or backward sloping solid segments 94 that provide a substantially solid face to solids in the SUMP 86, and a corresponding series of substantially horizontal openings 93 that allow the liquid and finer suspended solids to pass through the panel 67 under the action of water pressure, anid thence to the outlet stump 89 and the outlet 30/10 '00 MON 11:53 [TX/RX NO 6570] CCL 2000 12:05 SPRUSON AND FERGUSON 61292615486 NO. 1756 P. 18 19 A solid deflection panel 88 may be located below the lower portion of the upper separation panel 84, sloping down from the top edge of the transition panel 85 to cover tbe lower separation panel 87- Liquid and finer suspended solids dropping down from the upper separation panel 84 are directed to the outlet collection sump 89 and thence to the outlet In another, similar, example of the invention, shown in Figure the solids collection sump 100 is divided into inlet and outlet sides by the lower separbtiol panel 87 fixed at its lower edge to the outlet side of the sump 100 and inclined back at an angle towards to lower edge of the transition panel The portion of liquid that reaches the sump 100 is forced by water pressure through the lower separation panel (formed with openings and solid segments as in the previous example), into the outlet side of the sumip 100, over the lip 101 of the sump 100, into the outlet collection sump 89 and thence to the 9:outlet 90. In all other ways this embodiment of the invention is the same as described in the previous embodiment.

The embodiment of Figures 22 and 23 show the use of the concept of the invention together with a dynamnic separator.

This embodiment can be particularly useful for a mixed system of sewage and stonimwater. As previously mentioned, such systems normally carry the sewage load and this can be multiplied many times when there is, say a heavy storm.

Sewage treatment plants may w~ell not have the capacity to cope 30/10 '00 MON 11:53 [TX/RX NO 6570] OCT. 2000 12:05 SPRUSON AND FERGUSON 61292615486 NO. 1756 P. 19 2S with the increased flow and there can be a loss of raw sewage and any stormwater carried debris.

In the embodiment, under normal conditions, the inlet 110 will carry sewage and any stormwater which will enter the chamber 112 and thence to the dynamic separator 115. In this the sewage and water will pass through aperture 116 to outlet 117.

Under conditions where there is greater flow, where there is substantial stormwater, then the' liquid and entrained solids which come through the inlet 110 move along the separation .4 plate 113 which acts as described in the previous embodiments, water will pass through the plate 113 whilst the entrained solids will be moved along the surface of the plate to the dynamic separator 115. Thus there is a restriction on the *e quantity of water which enters the dynamic separator. With *oo this increased flow, too, there will be a build up of the solids adjacent the centre of the dynamic separator and these, together with the entrained water, will move to the centre, by vortex action, and will pass through, the outlet 116. The remainder of the water will tend to be displaced by further incoming water, it will move about the baffle 114 and will tend to re-enter chamber 112.

The capacities of the chamber 112 and the dynamic separator 115 can be 'selected to enable the maximum outlet of the separator to be the maximum acceptable at the sewage treatment 30/10 '00 MON 11:53 [TX/RX NO 6570] OCT. 2000 12:05 SPRUSON AND FERGUSON 61292615486 NO, 1756 P. plant and -the maxi mum throughput such as to enable the apparatus to cope with anticipated maximum flows.

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Claims (9)

1. An apparatus to separate solid matter from a liquid stream passing through the apparatus along a predetermined path, said apparatus including a separation panel located on said path and having a face over which the liquid passes in a predetermined direction, the panel having a plurality of apertures through which solid matter of a size larger than a predetermined size cannot pass, said apertures being located at positions spaced both in said predetermined direction as well as generally transversely of said direction, and wherein said panel has protruding solid segments associated with the apertures which shield the apertures with respect to liquid passing the panel by forming a substantially closed face to the liquid passing in said direction.

2. The apparatus of claim 1 wherein said panel is expanded metal mesh.

3. The apparatus of claim 2 wherein said panel is generally flat.

4. The apparatus of claim 2 wherein said panel is generally vertically oriented. The panel of claim 3 wherein said panel extends generally horizontally transverse of said direction, and slopes downwardly in said direction. S6. The apparatus of claim 2 wherein said panel is arcuate so that said face is concave. o•

7. The apparatus of claim 6 wherein said face is generally vertically :oriented.

8. The apparatus of claim 6 wherein said panel is arcuate so that said face oooo is convex. °go•

9. The apparatus of claim 8 wherein said face is generally vertically S 25 oriented. o*

10. The apparatus of claim 1 wherein said apertures face in a direction ,,,,which has a direction component in said predetermined direction.

11. An apparatus to separate solid matter substantially as herein before described with reference to the accompanying drawings. [R:\LIBF]01691 .doc:Izg