AU727926B2 - Apparatus and methods for separating solids from flowing liquids or gases - Google Patents

Description

P/00/01i1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: gases Apparatus and methods for separating solids from flowing liquids or The following statement is a full description of this invention, including the best method of performing it known to us: FHPMELC699O60004. 1 1A APPARATUS AND METHODS FOR SEPARATING

SOLIDS

FROM FLOWING LIQUIDS OR GASES Field of the invention This invention relates to apparatus and methods for separating solids or particulate matter from flowing liquids or gases. The invention has particular, although not exclusive, application to the filtration of floating and entrained solids from discharges of water. One particular application of the invention is in relation to storm water drain technology.

Background to the Invention There are many applications where it is desirable to separate solids from a flowing liquid.

Such applications include the following.

1. Separation of solids from storm water In many parts of the world, storm water is directed to waterways and seas. Storm water is a major carrier of solid pollutants, such as plastics, cans, tree branches and animal faeces, amongst other things, to waterways and seas.

Endeavours have been made to date, to limit the passage of at least some of these materials to waterways and seas. One method which has been used is to employ grates across outlets from the drains. This method has been generally unsatisfactory because the size of the grate must often be such as to enable water to pass, even if solid material is held against the grate by water pressure. Accordingly, it has been necessary that the grate be of substantial opening size. A further problem is that even large grates can become blocked, and it is essential to provide a flow path around or over the grate to prevent build up of water upstream in the drainage system. A second alternative proposed has been the use of systems, such as cyclones and dynamic separators, to remove the waste. While these can be efficient in some circumstances, they are often too expensive to be used in the whole of a storm water drainage system.

2. Separation of liquid from sewerage A major difficulty with many sewerage plants is the sheer volume of liquid to be handled.

This is aggravated where a "mixed" system, that is, a system which carries both sewerage and storm water, is used. In many cases, sewerage plants could hand4e more sewerage if the quantity of liquid delivered could be reduced. This could occur if, for example, liquid was removed from the sewerage before it enters into trunk sewers. To date, this has not been considered feasible.

Further, there are also many regions in the world where storm water and sewerage are received by the same system. This can cause difficulties where there are heavy rains which 10 overload the system, as it is undesirable to permit raw sewerage to pass to overflow.

3. Removal of pollutants from industrial wastes 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 will provide economies both to the plant and to the authority, if the cost 15 of the earlier removal of polluted matter was less than the cost of cleaning up pollution at a later time.

ooooo These are merely illustrations of the many uses to which an apparatus or method for separating solids from a flowing liquid, could be put. There are many other such applications which could be described.

In our International Patent Application number PCT/AU94/00061, we disclosed and claimed apparatus and methods for separating solids from flowing liquids. We believe that the apparatus and methods disclosed in that application provide very good results in applications requiring the separation of solids from flowing liquids. We have now developed improvements and/or refinements to the invention disclosed in that application, which we believe provide even better results than those disclosed in our earlier application.

Summary of the Invention According to the invention there is provided an apparatus to separate solid matter from a liquid stream passing through the apparatus, said apparatus including: a generally cylindrical separation panel surrounding an interior space and being oriented so as to have a generally upright longitudinal axis, the panel further having a plurality of openings being adapted to remove solid material greater than a predetermined size from liquid passing through the panel; a chamber member surrounding the panel and cooperating therewith to provide a 1o chamber portion into which the liquid passes after passing through the panel; an inlet to deliver the liquid stream to said space; an outlet extending from said chamber portion, the outlet being positioned with -respect to the chamber so that at least a portion of said panel is submerged; wherein said apparatus is adapted to cause the liquid stream to circulate in said is space about said axis, and said panel has deflective segments associated with the openings and projecting inwardly with respect to said space to inhibit particulate matter of at least said predetermined size from blocking said openings by the openings being positioned behind the segments relative to the flow of liquid there passed.

Preferably, said inlet directs the liquid so as to circulate within said space about 20 said axis.

Preferably, said apparatus further includes a receptacle to receive particulate matter removed from said stream by said panel.

In a preferred embodiment said receptacle is located below said space.

Preferably, said inlet and said outlet are positioned at substantially the same height.

Preferably, said inlet and outlet are substantially aligned.

In a preferred embodiment, said panel provides an inner wall surrounding said space and said inlet directs said stream substantially tangentially with respect to said inner wall.

Brief Description of the Drawings Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein: [R:\LIBTT]02550.doc:aer Fig 1 is a plan view of one example of a separator made in accordance with the invention; Fig 2 represents a view (in the direction of the arrow marked in Fig 1 of a vertical section of the separator shown in Fig 1, taken along the line A-A in that Figure; Fig 3 shows an enlarged horizontal section of part of a separator panel for use in the invention; and Fig 4 is a view from the side of a vertical section through an exemplary separator made in accordance with the invention.

Referring now to the accompanying drawings, Fig 1 shows a plan view of an apparatus which could be used to separate solids from a flowing liquid, such as water (and particularly, storm water). The apparatus shown, generally denoted 25, includes a separation panel 1, which as depicted, is of a generally circular shape, when viewed in horizontal cross-section. When viewed in three dimensions (as shown more particularly in Fig it can be seen that the separation panel 1 has an open-ended generally cylindrical S° configuration.

As shown in Figs 1 and 2, the separation panel 1 is located within a separation chamber 2.

The liquid enters the separation apparatus 25 via an inlet means 3, in the direction of the arrow 27 shown in Fig 1. As shown in Fig 1, the inlet channel 3 curves to the left until reaching the body 37 of the separator 25, where water and entrained solids or particulate matter are presented through an opening 8 into the interior 19 of the separation panel 1.

The generally cylindrical configuration of the separation panel 1 is such that when the water leaves the opening 8 and enters the interior (or confines) 19 of the separation panel 1, a circular flow motion is established within the confines 19 of the separation panel 1, in the direction shown by the arrow 29 shown in Fig 1.

Referring now to Fig 3, it will be seen that the exemplary separation panel 1 depicted consists of a number of deflection means in the form of solid deflective segments 10 which generally present a closed face to the direction of flow of the liquid (as shown by the arrow numbered 31 in Fig 3) within the separation panel 1. Behind each deflective segment 10 in the separation panel, there is an opening 9. As illustrated, each opening 9 is disposed at an angle to the direction of flow of the liquid in the separation panel 1. Moreover, the openings 9 are all of a predetermined size, which is such as to permit the passage only of particulate matter smaller in size than that of the openings. The liquid is of course, also able to pass freely through the openings. In use of the separation apparatus 25, the effect of this arrangement of features is that only the liquid, and solids or particulate matter of a size smaller than that of the openings 9 are able to pass through the separation panel. Solids or particulate matter of a larger size are therefore trapped within the confines 19 of the separation panel. Moreover, the circular motion of the liquid within the confines 19 of the separation panel means that trapped solids or particles are continuously deflected from the interior wall 33 of the separation panel. The net effect of this arrangement is therefore that the separation panel 1 is substantially self-cleaning.

S Solids trapped within the confines 19 of the separation panel are therefore caused to continue moving by the circular flow until they settle under gravity, or, if floatable, are retained on the surface. At the same time, untrapped solids and the liquid are able to pass through the separation panel into the upper portion 5 of the separation chamber 2, and thence to the outlet means 6 (which, as shown in Fig 1, may take the form of a channel, pipe or other suitable outlet structure).

oooo 0 20 As shown in Fig 3, preferably, the flow of the liquid or gas outside the confines of the oo separation panel is in a direction opposite to the direction of its flow within its confines.

This counter-current flow motion on opposite sides of the separation panel establishes a kinetic equilibrium which in turn facilitates the generally self-cleaning function of the circular flow motion established within the confines 19 of the separation panel.

As shown in Figs 2 and 4, the separation apparatus 25 may also include a receptacle 4, such as a collection sump, for the containment (and removal, if desired) of settleable solids. The sump 4 may be sized or configured so as to slow down the circular flow of the liquid 6 at the lower portion of the apparatus 25, so as to facilitate settlement of solids. The sump 4 may also be provided with any suitable means to facilitate the removal of settled solid or particulate matter. Such means could include, for example, periodic removal by education.

or a mechanical bucket or basket that is suspended in the sump. Floatables which are left floating on the top of the body of water treated by the separation apparatus 25 could be removed by any convenient means.

As shown more particularly in Fig 4, the separation apparatus may also include means for assisting the settlement of solids into the sump 4. The means shown in Fig 4 take the form of a downwardly directed annular flange or baffle 17, which assists in directing downwardly moving solids into sump 4. The flange or baffle 17 also substantially prevents the circular motion of the liquid or gas within the upper regions of the separation chamber from being transferred into the sump 4.

Referring now to Fig 2, as illustrated, the cylindrical separation panel 1 may be fitted with a continuation part 7 of the same material (or of another, generally impervious material) above the level of the normal inlet flow. This continuation part 7 ensures the retention of SC floating solids if the separation apparatus is subjected to head pressure (eg during flood conditions), if the apparatus is being used, for example, for the removal of litter from urban oo•° stormwater runoff.

SWhere particularly "purified" liquids or gases are required at the conclusion of the filiation 20 procedure, it is possible for the outlet from one separation apparatus according to the invention to feed into the inlet for a second such separator, and therefore, for the liquid or gas to be filtered sequentially by two or more such separators, arranged in series. In such an arrangement, the size of the openings in the separation panels for the second and subsequent separators could be sequentially (and increasingly) smaller, so that each subsequent separator removes increasingly finer particles. Hence, by this arrangement, very high, or indeed, any desired level of filtration or purification could be achieved.

While much of the aforegoing description of the preferred embodiments has been concerned with apparatus for separating solids entrained in liquids, it is to be understood that the invention is equally applicable to the separation of solids entrained in gases.

Generally, for more efficient operation of gas/solid separators constructed in accordance with the invention, it would be necessary for the separator to be constructed as a sealed unit, so as to prevent the undesired escape of gases undergoing filtration. (This is a feature which could also be utilised in some liquid/solid separators constructed in accordance with the present invention). In this way, solid matter entrained in exhaust gases and gaseous emissions from various manufacturing plants, could be filtered in much the same way as solid-bearing liquids are treated, using the apparatus and methods of the present invention.

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Claims (8)

1. An apparatus to separate solid matter from a liquid stream passing through the apparatus, said apparatus including a generally cylindrical separation panel surrounding an interior space and being oriented so as to have a generally upright longitudinal axis, the panel further having a plurality of openings being adapted to remove solid material greater than a predetermined size from liquid passing through the panel; a chamber member surrounding the panel and cooperating therewith to provide a chamber portion into which the liquid passes after passing through the panel; an inlet to deliver the liquid stream to said space; an outlet extending from said chamber portion, the outlet being positioned with respect to the chamber so that at least a portion of said panel is submerged; wherein said apparatus is adapted to cause the liquid stream to circulate in said space about said axis, and said panel has deflective segments associated with the openings and projecting inwardly with respect to said space to inhibit particulate matter of at least said predetermined size from blocking said openings by the openings being positioned behind the segments relative to the flow of liquid there passed.

2. The apparatus of claim 1 wherein said inlet directs the liquid so as to circulate within said space about said axis.

3. The apparatus of claim 1 or 2 further including a receptacle to 20 receive particulate matter removed from said stream by said panel.

4. The apparatus of claim 3 wherein said receptacle is located below o said space.

5. The apparatus of any one of claims 1 to 4 wherein said inlet and said outlet are positioned at substantially the same height. S 25

6. The apparatus of any one of claims 1 to 5 wherein said inlet and outlet are substantially aligned.

7. The apparatus of any one of claims 1 to 6 wherein said panel provides an inner wall surrounding said space and said inlet directs said stream substantially tangentially with respect to said inner wall.

8. An Apparatus to separate solid matter from a liquid stream passing through the apparatus substantially as hereinbefore described with reference to any one embodiment as that embodiment is illustrated in the accompanying drawings. Dated 16 September, 2000 Paul Blanche,Stephen Crompton Patent Attorneys for the Applicant/Nominated Person SSPRUSON FERGUSON [R:\LIBTT]02547.doc:aer