WO1997010389A1

WO1997010389A1 - Filter

Info

Publication number: WO1997010389A1
Application number: PCT/AU1996/000582
Authority: WO
Inventors: Russell Ball-Guymer
Original assignee: Actew Corporation Ltd.
Priority date: 1995-09-15
Filing date: 1996-09-16
Publication date: 1997-03-20
Also published as: AUPN550295A0

Abstract

A filter (2) including first filtering means (4, 6) for preventing an elongate inflexible object from passing through sideways and second filtering means for preventing an elongate inflexible object from passing through lengthways. The first filtering means includes opposed and interleaved filtering members (4, 6) and the second filtering means includes a circuitous path (14).

Description

1 "FILTER"

FIELD OF THE INVENTION

This invention relates to a filter.

This invention has particular but not exclusive application to the filtering of potential blockage- causing objects from wastewater streams, and reference will hereunder be made to such use.

BACKGROUND ART

Conventionally, wastewater streams are reticulated to a treatment site via pipes which are often buried, submerged or otherwise difficult to access.

It will be appreciated that blockages in such pipes, typically caused by large inflexible objects, are highly undesirable and present costly and difficult maintenance challenges.

It is known to use bar screens to filter objects from a wastewater stream with a view to avoiding the above described blockages. Such bar screens use a plurality of parallel and spaced bars which are transversely disposed across the wastewater flow.

A drawback with bar screens is that they capture many objects which do not present a potential risk of blockage downstream in the pipe. Bar screens quickly become choked with flexible material such as paper and other articles which are generally known in the wastewater treatment art as "rags". This causes a substantial loss of hydraulic head across the screen and necessitates regular flow shutdown and cleaning of the screen. Furthermore, "rags" and other objects recovered during cleaning must then be disposed of. SUMMARY OF THE INVENTION

This invention in one aspect resides in a filter including:- a first set of spaced filtering members; and a second set of spaced filtering members, wherein the second set of filtering members are generally opposed to the first set of filtering members and are offset with respect to the first set of filtering members.

Preferably, the spacing of the second set of filtering members corresponds to the spacing of the first set of filtering members.

Preferably, the respective sets of filtering members are interleaved. Most preferably, the respective sets of filtering members are partially interleaved.

In the preferred embodiment, the opposed filtering members converge in the downstream direction. It is preferred that the opposed filtering members converge smoothly and gradually to avoid "rags" lodging on the filtering members. Preferably, the opposed filtering members converge to be partially interleaved and thereafter diverge.

Preferably, one set of spaced filtering members are mounted on a generally planar mounting means, the mounting means including spaced recesses corresponding to the other set of spaced filtering members. I t h e preferred embodiment, the second set of spaced filtering members are mounted on the generally planar mounting means, the mounting means including spaced recesses corresponding to the first set of spaced filtering members.

Preferably, a circuitous flow path which obstructs passage of long rigid objects which have passed lengthways through the first and second sets of filtering members is disposed downstream of the first and second sets of filtering members. In the preferred embodiment the circuitous flow path is defined by downstream extensions of the surfaces on which the respective filtering members are mounted.

Preferably, the sets of filtering members may be relatively displaced to facilitate cleaning of the filter. In the preferred embodiment, the first set of filtering members is pivotably mounted with respect to the second set of filtering members for movement between a filtering position and a cleaning position.

Preferably, the filter includes overflow means including a third set of filtering members and a fourth set of filtering members, the third and fourth sets being generally opposed and interleaved. In this arrangement, the third set of filtering members consists of a plurality of parallel and spaced bars, the free ends of the bars interleaving with the fourth set of filtering members. The fourth set of filtering members pivot with the first set of filtering members relative to the second set of filtering members.

In another aspect the invention resides in a filter including:- first filtering means for preventing an elongate inflexible object from passing through sideways; and second filtering means for preventing an elongate inflexible object from passing through lengthways. Preferably, the first filtering means includes a first set of spaced filtering members and a second set of spaced filtering members and preferably the second filtering means includes a circuitous path.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention, wherein:-

FIG 1 is a exploded perspective view of a filter according to the invention;

FIG 2 is an elevational view from a point immediately downstream of the first and second sets of spaced filtering members;

FIG 3 is a schematic and sectioned side elevational view of the assembled filter of FIG 1; and

FIG 4 is a schematic and sectioned side elevational view of the assembled filter of FIG 1 shown in cleaning configuration.

BEST MODE

With reference to the FIGS, filter 2 includes a first set of spaced filtering members 4 and a second set of spaced filtering members 6, wherein the second set of filtering members 6 are generally opposed to the first set of filtering members 4 and are offset with respect to the first set of filtering members 4.

With reference to FIG 2 it will be observed that the respective sets of filtering members are partially interleaved. That is, they overlap such that a long inflexible object can not pass between the respective sets of filtering members sideways. However, a long object could potentially pass lengthways between the first and second sets of filtering members.

With reference to FIGS 3 and 4, it will be observed that the opposed filtering members 4 and 6 converge smoothly and gradually in the downstream direction such that "rags" and the like do not lodge on the filtering members. When an object strikes a filtering member it is smoothly deflected to the "throat" of the filter whereat the opposed filtering members interleave. Small or flexible objects will pass through the throat whilst large inflexible objects will be trapped.

The second set of spaced filtering members 6 are mounted on a generally planar mounting means 24, the mounting means 24 including spaced recesses 8 (see FIG 2) corresponding to, and located opposite of, the first set of spaced filtering members 4.

A circuitous flow path 14 (FIG 3) which obstructs passage of long rigid objects which have passed lengthways through the first and second sets of filtering members 4 and 6 is disposed downstream of the first and second sets of filtering members 4 and 6. The circuitous flow path 14 is defined by downstream extensions 26 and 28 of the surfaces on which the respective filtering members are mounted.

The filter 2 includes overflow means in the form of a third set of filtering members 10 and a fourth set of filtering members 12, the third and fourth sets being generally opposed and interleaved in a manner similar to the first and second sets of filtering members. The third set of filtering members 10 consists of a plurality of parallel and spaced bars, the free ends of the bars interleaving with the fourth set of filtering members 12. Filtering members 10 are mounted in a grate 36 (FIG 1) which is pivotably mounted in bracket 38 which is mounted to a support (not shown).

Second set of filtering members 6 and recesses 8 are disposed on component 18 which also includes spaced side walls 40. The outer surfaces of spaced side walls 40 abut the same support to which bracket 38 is mounted. Typically, the support is a vertical concrete wall. Side wall 40 also includes apertures 22 and 32. First set of filtering members 4 are disposed on component 16 which consists of sub-components 16a and 16b which in use are fixed together.

Sub-component 16b includes spigot 20 which engages aperture 22 in side wall 40 whereby component 16 may be pivoted relative to component 18 between the filtering configuration illustrated in FIG 3 and the cleaning configuration illustrated in FIG 4. Sub-component 16b also includes a locking bar 30 operable by handle 34 to engage aperture 32 in side wall 40 and fix component 16 in the filtering configuration against rotation relative to component 18.

Sub-component 16a is fixed in use to sub-component 16b and includes fourth set of filtering members 12. Downstream extension 28 of sub-component 16b cooperates with downstream extension 26 of component 18 to define circuitous flow path 14.

In use, component 16 is pivoted relative to fixed component 18 to the filtering configuration illustrated in FIG 3. It is locked in this configuration by the engagement of locking bar 30 in aperture 32.

As shown in FIG 3 flow passes through the first and second sets of filtering members from left to right as shown by the arrows. On passing through the filtering members, potential obstruction causing objects are trapped whilst "rags" and the like pass through. Any long inflexible objects which pass lengthways through the filtering members are trapped in the circuitous path 14. To clean the filter, the flow is stopped, the locking bar disengaged, and component 16 is pivoted to the cleaning configuration illustrated in FIG 4. Handles 42 are provided to facilitate this operation. Trapped objects may then be manually removed as necessary. In the event of excessive inflow or blockage of the first and second sets of filtering members, the level on the upstream side of the filter will build up until it cascades over the top of component 16 thereby being filtered by third and fourth sets of spaced filtering members 10 and 12.

It will of course be realised that whilst the above has been given by way of an illustrative example of this invention, all such and other modifications and variations hereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. A filter including:- a first set of spaced filtering members; and a second set of spaced filtering members, wherein the second set of filtering members are generally opposed to the first set of filtering members and are offset with respect to the first set of filtering members.

2. A filter as claimed in claim 1, wherein the first and second sets of filtering members are interleaved.

3. A filter as claimed in claim 2, wherein the opposed and interleaved filtering members converge in the downstream direction.

4. A filter as claimed in claim 3, wherein one set of spaced filtering members are mounted on a generally planar mounting means, the mounting means including spaced recesses corresponding to the other set of spaced filtering members.

5. A filter as claimed in claim 1, wherein a circuitous flow path which obstructs passage of long rigid objects which have passed lengthways through the first and second sets of filtering members is disposed downstream of the first and second sets of filtering members.

6. A filter as claimed in claim 5, wherein the circuitous flow path is defined by downstream extensions of the surfaces on which the respective filtering members are mounted.

7. A filter as claimed in claim 1, wherein the sets of filtering members may be relatively displaced to facilitate cleaning of the filter.

8. A filter as claimed in claim 7, wherein the first set of filtering members is pivotably mounted with respect to the second set of filtering members for movement between a filtering position and a cleaning position.

9. A filter as claimed in claim 1, wherein the filter includes overflow means including a third set of filtering members and a fourth set of filtering members, the third and fourth sets being generally opposed and interleaved.

10. A filter as claimed in claim 9, wherein the third set of filtering members consists of a plurality of parallel and spaced bars, the free ends of the bars interleaving with the fourth set of filtering members.

11. A filter including:- first filtering means for preventing an elongate inflexible object from passing through sideways; and second filtering means for preventing an elongate inflexible object from passing through lengthways.