WO2008056115A2

WO2008056115A2 - Filter elements for biological filtration arrangements

Info

Publication number: WO2008056115A2
Application number: PCT/GB2007/004209
Authority: WO
Inventors: Mark Barrett
Original assignee: Warden Plastics Limited
Priority date: 2006-11-07
Filing date: 2007-11-05
Publication date: 2008-05-15
Also published as: GB0721668D0; GB2443726A; GB0622134D0; WO2008056115A3

Abstract

An extended surface area filter element construction including a central body (1) mounting a plurality of additional surfaces (2), serving to provide a greatly increased surface area as compared with a central body of the same size but not having additional surfaces that are formed by surfaces radially extending from the central body. The filter elements can be of moulded plastics and including a cylindrical tubular core from which project a plurality of radially directed fins (2) whose radial length increases stepwise from each end of the core body to a maximum length central of the length of the core body, thereby effectively to provide a generally conical double back-to-back conical appearance.

Description

FILTER ELEMENTS FOR BIOLOGICAL FILTRATION ARRANGEMENTS

This invention relates to filter elements for use with apparatus for and/or methods of facilitating biological filtration of water biological waste materials-

It is well known to treat i.e., filter, water containing biological materials such as 5 arises in relation to the management and disposal of human and animal food materials and general waste such as is commonly known as sewage material

In relation to at least the initial stages of such treatment it is known to retain the material to be treated in settling containers/tanks within which the sewage material undergoes at least the stages of the breakdown of the material content by I o bacterial action.

In practice, the bacteria involved require and make use of any surface available within the container/tank such as the walls of the container/tank and those of any other surfaces available within the container/tank as a 'rest' position. Whilst in such 'rest' position the bacteria biologically react with the waste material within 15 the container/tank and in so doing numerically multiply.

In view of the purpose and function of the installation fresh sewage materials are added to the content of the materials already present in the associated container/tank since the filtering capacity and efficiency is related to the overall bacteria content of the container/tank. 0 Since the bacteria require a surface upon which to function it is known to provide in the container/tank of a filtration plant, additional surfaces upon which the bacteria may anchor thereby to enhance the filtration capability of the associated filtration plant. For example, it is known to provide within a container/tank a plurality of elements commonly referred to as 'filter elements' such as, for example,, cylindrical tubes having a corrugated outer surface which serves to increase the surface area presented to the bacteria. It will thus be appreciated that by means of provision of such bodies the total surface area presented by the bacteria is many times greater than the actual surface area of the container/tank whereby the filtering of the installation is correspondingly increased.

In practice, as a results of the bacterial action in conjunction with the nature of the biological waste, material the surfaces. of the filter elements can become loaded with settled material thereby covering in the actual active surfaces of the filter elements and in so doing reduces the overall area of the surface available for the supporting the bacteria involved together with reduction in the rate of flow of waste material..

To deal with this situation is has been found necessary to clean or otherwise /remove material deposited onto the filter elements.

Bearing in mind that the containers/tanks involved can be such as to accommodate several cubic metres of water and sewage content, the removal of the filter elements can be in practice an almost impossible task. Particularly in situations where several hundred/thousands of individual filter elements are freely distributed through out the container for the material to be treated.

What is more the positioning of the container within its surroundings may itself militate against access enabling satisfactory removal of the individual filter elements for what ever purpose such as replacement cleansing and the like.. OBJECT OF THE INVENTION

It is an object of the invention to provide filter elements that are intended when in use to be capable of being randomly disposed within a filtering container/tank of a filtration plant

STATEMENTS OF THE INVENTION

According to a first aspect of the invention there is provided an extended surface area filter element construction including a central body mounting a plurality of projections, serving to provide a greatly increased surface area as compared with a central body of the same size but not having such projections.

Preferably the additional surfaces are formed by surfaces laterally/radially extending from the central body.

In a preferred arrangement the projections extending from the core comprise a plurality of fins each having a stepwise. i.e., serrated formation, free edge region.

Conveniently the serrated edge formation of the fins is such as to enable the filter elements to lock together once they have gravity wise settled following their introduction into a container/tank in such manner as to provide a integrated aerobic filter bed.

In a preferred construction the elements are formed from a plastics material and comprise a cylindrical tubular core from which a plurality of fins radially project

In a preferred formation alternate fins are of different radial length.

In a farther construction the filter element comprise a moulded plastics element having a cylindrical tubular core from which project a plurality of radially directed fines whose radial length increases stepwise from each end of the core boy to a maximum length centrally of the length of the core body, thereby effectively to provide a generally conical double back-to-back conical appearance..

Preferably the fins at the region of maximum radial length are stiffened by a stiffening ring whose plane is perpendicular to the axis of the core.

In a particular embodiment the edge of the ring is provided with cut-outs that serve to increase the effective length of this outer edge.

In a further preferred construction a secondary smaller diameter ring connects with the core body and the fins at the central region thereof the secondary rings being coaxial with the axis of the core interconnecting the fins in such manner as to stiffen the fins against distortion.

In practice, the individual filter elements can be formed from a polyethylene or plastics material appropriate to the operation conditions of an aerobic treatment plant. .

In a preferred manner of using the filter elements of the invention in an aerobic filtration plant includes the step of introducing the fiher elements in at least one secondary enclose/container that is in turn introduced into a further container forming part of an aerobic filtration plant and causing material required to be filtered to pass through the secondary enclosures) and said container,

Conveniently the secondary enclosure/containers are such as to allow the filter element content thereof to settle under gravity to a consolidated mass of extended area filter elements. Additionally each said secondary enclosure is provided with means for facilitating fts removal from within the further container.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which;

Figure 1 is a plan view of a first embodiment of a individual filter element;

Figure 2 is a vertical section of the element of Figure 1,

Figure 3 is a plan view of a second embodiment of a individual filter element,

Figure 4 is a vertical section of a second embodiment of a individual flitter element and

Figure 5 very schematically illustrates a mode of using the filter elements of the invention.

In the Figures 1 and 2 the embodiment of the individual filter element as shown therein includes central cylindrical core 1 from which extends a plurality of radially directed webs or fins 2

As indicated in Figure 1 the free edge 3 of each fin 2 is stepped outwards in two series of triτee regular steps 4 from a minimum distance near each end 5 of the core 1 to a maximum distance located at a position 6 midways of the length of the core 1. The fins in the region of their maximum extensions from the core 1 are stiffened by an annular ring 7 that is integrally formed with the fins. Figure 3 illustrates in vertical section a second embodiment of a individual filter element 1 which includes a second stiffening ring 9 located intermediate the core 1 and the ring 7 . As will be noted each Fin 2 has two steps 4 to the opposite sides of the ring 7.

It will be understood that further stiffening rings (not shown) can be provided with a view to increasing the available surface area of the filter element.

It will be apparent that the formation of the individual filter elements as illustrated in the Figures each filter element comprises a multi-surface arrangement providing a considerable area upon which bacteria an settle.

polyethylene or plastics material appropiate to the operation conditions of an aerobic treatment plant. .

It will be appreciated that the individual filter elements can be of many different forms other than that illustrated in the Figures.

For example, the individual filter elements may be comprise a cylindrical core having, internal radially directed webs in addition to the above mentioned radially directed fins extending from the outer surface of the core.

In practice, the manner of the addition of such additional webs/fins or the like would be such as to ensure that adequate flows of water and entrained biological materials are able freely to pass through an agglomeration of the filter elements, and further such as not to unnecessarily lead to increase in any clogging of the elements. Whilst the above discussed embodiments have involved cylindrical cores in practice the formation of the elements is not restricted to cylindricaJ form.

As will be understood the main feature of the elements of the filter elements of the invention is the maximisation of the surface area presented to the bacteria involved and thus available to the filtering processes.

As will be appreciated that during sustained use of the filter elements they tend to become blocked/clogged thereby reducing, the material throughput efficiency of the filtering system. In addition, there is the possibility that the activity of the bacteria may also diminish As a result of these factors it becomes necessary from time to time to replace the blocked/clogged individual filter elements with new filter elements or reclaimed filter elements.

Preferably the free edge region edge formation of the fins is such as to enable the filter elements to lock together once they have gravity wise settled following their introduction into a container/tank in such manner as to provide a integrated aerobic filter bed.

In practice, the free edge region edge formation of the fins is such as to enable the filter elements to lock together once they have gravity wise settled following their introduction into the container/tank in such manner as to provide a integrated aerobic filter bed.

This settlement of the filter elements within their containing container/tank they can result in a relatively tightly packed mass which makes it difficult to displace the filter elements when it is required to replace them.

Historically the removal of the individual filter elements from their container/tank has frequently been a tedious time consuming activity and at times somewhat practically difficult in view of the siting of the container/tank frequently underground and only accessible through, a manhole.

With a view to removing such difficulties the filter elements as mentioned above the container/tank filling of the individual filter elements can be introduced into one of more secondary containers/enclosures whereby the replacement of used filter elements in a filtering installation reduces to removing the secondary containers/enclosures from the container/tank and replacing them with replacement secondary containers/enclosures and their content of fresh individual filter elements

In practice the handling of these secondary containers/enclosures and their individual filter element content can be facilitated by providing each secondary enclosure with a handling rope of the like whose free end is retained in a position affording easy access to such handling ropes. For example, the handling rope ends can be stored adjacent to a manhole cover giving access to the interior of the filter installation.

The construction of the secondary enclosure/containers is such as to enable easy access of the water and any entrained material to be treated in the filtration plant.

Thus the secondary enclosures utilises a material enabling easy ingress of the flow of waste water and any entrained waste material 'solids' into the interior of the secondary enclosures so that the bacteria located on the filter elements can react with the waste material entering and also have easy egress from the secondary enclosures.

Thus the secondary enclosures are conveniently made from a net/mesh like material of such mesh aperture size as to be able to retain the individual filter elements there within whilst providing as large as possible area cross section for the throughput of water borne waste material into the secondary enclosure.

As can be seen from Figure 5, what ever the specific foπn/construction of the individual filter elements 2 the elements are introduced into one or more secondary enclosures 10 that are installed into a main container/tank 11 forming part of a treatment plant (not otherwise shown)

The number of the secondary enclosures 10 used is governed by the waste material receiving volume of the main container/tank 11 and the physical size of the secondary enclosures 10 and its individual filter element content.

In use such secondary enclosures will allow the filter elements to settle within the secondary enclosures to form a consolidated mass of the elements the presents a very large surface area for the bacteria to 'rest' and present a very large surface area of bacteria to the waste introduced into the filtering installation whilst enabling adequate throughput of the waste material to be treated..

It will be appreciated that the mesh like form of the secondary enclosure/containers facilitates the relative movement of the filter elements within the secondary enclosures during at least their initial introduction into the container/tank 11 whilst the enclosure and their filter element content gravity wise settles to a self moulding rest condition relative to the walls of the container/tank and any other secondary enclosures and the filter elements content.

Claims

1. An extended surface area filter element construction including a central body (1) mounting a plurality of additional surfaces (2), serving to provide a greatly increased surface area as compared with a central body of the same size but not having additional surfaces..

2. An extended surface area filter element as claimed in claim 1, and wherein the additional surfaces are formed by surfaces (2) laterally/radially extending from the central body.

3. An extended area filter construction as claimed in claim 1 or 2, and wherein the additional surfaces comprise a plurality of fins (2) each having a stepwise/serrated formation (3) to their free edge regions.

4. An extended surface area filter element as claimed in claim 3, wherein the free edge region edge formation of the fins (2) is such as to enable the filter elements to lock together once they have gravity wise settled following their introduction into a container/tank in such manner as to provide a integrated aerobic filter bed.

5 An extended area filter element as claimed in claim 3 or 4, and wherein alternate fins (2) are of different lateral/radial length.

6 An extended surface area filter element, as claimed in claim 1 to 5, and wherein the elements are formed from a plastics material and comprises a tubular core (1) from which a plurality of fins providing said additional surfaces radially project.

7. extended area filter element as claimed in any one of the preceding claims, wherein the filter element comprises a moulded plastics element having a tubular core from which project a plurality of outwardly directed fins whose extension from the core increases stepwise from each end (5) of the core body (1) to a maximum length centrally (6) of the length of the core body.

8. An extended area filter element as claimed in claim 7, wherein fines provide a generally conical double back-to-back conical appearance..

9. An extended area filter element as claimed in claim 7 or 8, and wherein the fins (2) at their region of maximum extension are stiffened by a stiffening ring (7) o whose plane is perpendicular to the axis of the core.

10. An extended area filter element as claimed in claim 9, and wherein the outermost edge region of the ring (7) is provided with cut-outs that serve to increase the effective length of this outer edge.

11. An extended area filter element as claimed in claim 8, 9 or 10, and including a smaller diameter ring that connects with the core body and the fins at the central region thereof, said smaller diameter ring being coaxial with the axis of the core and arranged so to interconnect the fins in such manner as to stiffen the fins against distortion.

12. An extended area filter elements as claimed in any preceding claim, and when formed from a polyethylene or other plastics material appropriate to the operational conditions of an aerobic treatment plant. .

13. A method of using a plurality of extended area filter elements as claimed in any one of the preceding claims in an aerobic filtration plant including the step of introducing the filter elements in at least one secondary enclose/container (10) that is in turn introduced into a further container (11) forming part of an aerobic filtration plant and (10) and said container (11),

14. A method as claimed in claim 13, wherein the secondary enclosure/containers (10) are such as to allow the filter element content thereof to settle under gravity to a consolidated mass of extended area filter elements.

15. A method as claimed in claim 13 or 14, and in which each said secondary enclosure (10) is provided with means for facilitating its removal from within the further container (11).

16. A method as claimed in clim 15, in which a handling rope or the (12) is attached to each secondary enclosure (10) each such first mentioned container is provided with means whereby each such first mentioned container can be readilly removed with its content of elements from the further container (11).