AU695794B2 - Fluid filters - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT sc a a

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a a a a a a a a a e o a a Name of Applicant: Actual Inventor(s): Address for Service: FILTER 2000 PTY LTD (ACN 059 594 615) PAUL CHARLES LINDBERG

INTELLPRO

Patent Trade Mark Attorneys Level D, 308 Edward Street BRISBANE, QLD, 4000 (GPO Box 1339, BRISBANE, 4001) FLUID FILTER Invention Title: Details of Associated S Provisional Application(s) No(s): Australian Patent Application No. PM7834 filed 1 September, 1994.

The following statement is a full description of this invention, including the best method of performing it known to me: -g THIS INVENTION relates to fluid filters, and to disposable filter elements therefor.

This invention is particularly suitable for, but not limited to, separating solids and/or non-aqueous liquids, such as contaminants, from non-aqueous miscible liquids, eg. petroleum products.

The invention is also applicable, inter alia, to separating solids from aqueous liquids.

AU-B-27314/92 (650176) (Filter 2000 Pty Ltd) discloses a filter element for a filter, and a filter incorporating such an element, where the element has a filter canister open at one end and closed at the other end; a centre tube is located substantially coaxially within the container; a filter medium is wound onto the 15 centre tube in sealing engagement with the centre tube and the wall of the canister, the wall of the canister being ribbed or otherwise profiled to deter tracking of the contaminants removed from the feedstock between the canister wall and the filter medium; the feedstock being S 20 filtered passes through the open end to the filter medium, and through a flow passage defined by the closed end of the canister and the filter medium to the centre S" tube. The filter elements in accordance with the above have been found to be particularly suitable for removing contaminants from lubricating oils, hydraulic oils and the like.

It has been found that using such filter elements for removing contaminants from fuel (eg.

petrol, diesel) that the contaminants are removed from the fuel within the first 25-50mm of flow through the filter medium and the balance of the filter medium tends only to act as a flow restrictor, with little additional filtering. This can create problems when the elements are used in the filtering systems of engines having high fuel flow rates.

It is an object of the present invention to provide a filter element which incorporates the advantageous features of the filter element hereinbefore described, and which minimises the disadvantages thereof.

It is a preferred object to provide a filter element which enables high flow rates. Other preferred objects of the present invention will become apparent from the following description.

In one aspect, the present invention resides in a filter element for a filter, the filter element including: a filter canister having a pair of open ends (forming respective inlets for the filter element); 15 a centre tube located substantially coaxially within the canister; a respective filter medium within the canister, disposed about the centre tube, and adjacent a respective open end of the canister; and S 20 a flow passage defined between the filter mediums and connected to the centre tube wherein: each filter medium is wound onto the centre tube in sealing engagement with the centre tube and the wall of the canister, the wall of the canister being ribbed or otherwise profiled to deter tracking of the contaminants removed from the feedstock between the canister wall and the respective filter medium; and the feedstock passes substantially axially through the respective filter medium to the flow passage so that the filtered feedstock or filtrate will pa s from the flow passage to the centre tube.

Preferably, the flow passage is filled with a material with a high transverse porosity, such as woven gauze.

Preferably, each filter medium is a roll of 4 facial quality paper tissue, a roll of toilet paper, or cotton, hemp, artificial or synthetic fibres or other suitable porous or foraminous material.

Preferably, the filter element is disposable and is discarded once the filter medium becomes fully charged with trapped and retained solids.

In a second aspect, the present invention resides in a filter for filtering of feedstock, including: a body or housing; an inlet to the housing to allow a supply of feedstock to be filtered in the housing; an outlet in the housing to allow flow of .o filtered feedstock or filtrate from the housing; 15 a hollow centre post, displaced coaxially within the housing, the wall of the centre post having fluid communication ports between the outside and the bore thereof, the bore being connected to the housing outlet; 20 at least one filter element as hereinbefore described within the housing; and filter element installation means providing i releasably sealable installation of the filter element(s) in the housing whereby the feedstock flows from the inlet to the outlet through the filter element(s).

Preferably, the housing is closed at its base and open at its top, the top being closed by a cap fitted with sealing means to engage the wall of the housing.

Preferably, the housing inlet and the housing outlet are at the base of the housing, as is a drain port to enable contaminated feedstock to be drained from the bottom of the housing.

Preferably, the open end of the (or uppermost) filter element is adjacent to the top of the housing so that at least a portion of the feedstock flows from the housing inlet up to the lid through an annular passage defined by the wall of the housing and the canister(s) of the filter element(s).

Preferably, the hollow centre post is disposed within, and sealably connected to, the centre tube.

Preferably sealing means seal against the flow of fluid between the housing and the centre tube, so arranged that the filtrate in the centre tube flows through the fluid communication ports into the bore of the centre post, and then to the housing outlet.

Preferably, the filter medium retaining ring S'is provided about the upper end of the centre tube and bears against the top of the filter medium; a compression spring about the centre post is interposed between the housing cap and the retaining ring to urge the retaining ring into engagement with the filter medium to seal the upper end of the centre tube and to 20 retain the filter medium in the canister; and a pressure knob, screw-threadably mounted on the centre post bears against one end of the centre tube to urge the filter element upwardly against the compression spring.

Preferably, respective sealing means seal the centre post to the centre tube.

To enable the invention to be fully understood, a preferred embodiment will now be described with reference to the accompanying drawings, in which: FIG 1 is a sectional side view of one embodiment of the invention; FIG 2 is a side view of the element; and FIG 3 is a plan view of the element.

Referring to FIGS 1-3, the filter element has a canister 11 (eg. of food quality steel) which has a ribbed side wall 12 and is open at both ends 13, 14 to

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6 enable feedstock to enter the element. A centre tube is provided coaxially within the canister 11 and has a bore 16. The centre tube 15 is separated into upper and lower sections by a passage (or a plurality of ports) 17 and one or more layers of woven gauze 18 extend from the passage 17 into the canister 11 to define a flow passage from the interior of the canister to the bore 16 of the centre tube.

A respective filter medium 19, 20 is a roll of facial quality tissue paper wound around the centre tube and in sealing engagement with the rib wall 12 of the canister 11 to prevent "tracking" of the solid :...contaminants through the element 10 between the canister wall 12 and the filter medium 19, In use, one or more of the filter elements are fitted to a filter 30 to be hereinafter described with reference to FIG i.

The filter 30 has a housing 31 of substantially cylindrical shape with a side wall 32 and a closed bottom wall 33, and at its base, brackets (not shown) are provided to mount the housing 31, eg. in an engine block or vehicle chassis (not shown).

The housing 31 is closed at its upper end by a cap 36 provided with a peripheral sealing ring 37 to engage the upper run of the housing side wall 32.

The housing inlet 38 is formed integrally with the bottom wall 33 and screw-threaded to receive a suitable fitting (not shown). A one-way check valve (not shown) in the housing inlet 38 prevents back pressure within the filter 30 building up within the feed line(s) to the filter.

A centre post 41, with an internal bore 42 has a plurality of fluid communication ports 43 through its wall to enable the passage of fluid from the exterior of the centre post 41 to the bore 42. The lower end of the

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centre post 41 is screw-threadably received in, and sealed to, the housing outlet 44 in the bottom wall 33 of the housing, the outlet being screw-threaded to receive a suitable fitting (not shown) connected to a fluid hose (also not shown), eg. connected to an engine fuel system.

A drain plug 44a is also provided in the bottom wall 33 of the housing 31 to enable contaminated feedstock, eg. contaminated water and sludge, to be drained from the housing.

A knurled knob 46 is screw-threadably mounted on the centre post 41 and has a washer 47 and seal 48 to engage the lower end of the centre tube 15 of the filter element 15 A compression spring 49 is disposed between a nut 50, screw-threadably mounted on the centre post 41, and a washer 51 and seal 52 which engage the upper end of the centre tube 15 of the filter element 10. A handle 53 at the upper end of the centre post 41, is S 20 fitted with a seal 54 to sealably secure the cap 36 to the housing 31.

The sealing of the filter 10 to the centre post 41 is effected by rotation of the knurled knob 46 which compresses the compression string 49, the centre tube 15 being urged into sealing engagement with the seal 52. Sealing of the centre post 41 to the cap 36 and the outlet 44, of the cap 36, the housing 31 is effected by tightening the handle 53 which engages tlhe threaded end of the centre post 41 within the housing outlet 44, compresses seals 54 and 37 between the handle 53 and the cap 36 and the housing wall 32, respectively.

The feedstock (eg. engine fuel) is introduced to the filter 30 via the inlet 38 (and its check valve) to a lower plenum 55 in the housing 31. A portion of the feedstock flows upwardly and substantially axially through an annular passageway 56 defined by the canister 11 and the housing side wall 32 to an upper plenum 57.

This feedstock then flows downwardly through the inlet of the filter element 10 to pass through the filter medium 19 and any solid contaminants are trapped and retained on, or in, the filter medium 19. Similarly, the balance of the feedstock, from lower plenum flows through the filter medium The filtered feedstock or filtrate, which is passed through the filter medium 19, 20 then flows :...substantially radially through the flow passage in the annular space defined between the filter medium 19, (and occupied by the gauze 18) and then through the passage 17 into the annular space defined by the bore 16 15 of the centre tube 15 of the filter element 10, and the centre post 41.

The filtrate passes through the ports 43 in the centre post 41, down the bore 42 thereof, and out the housing inlet 44 (to be supplied to the, eg. fuel 20 injection or carburettors of the engine).

While the filter element 10 is particularly suitable for removing contaminants from fuel, it may also be used to remove contaminants from lubricating oil or hydraulic oil, eg. in a secondary filtration system.

It will be readily apparent to the skilled addressee that for a higher capacity filter, a plurality of filter elements 10 may be stacked one on top of each other within an (extended length) housing, with spaces provided between the filter elements to enable radial flow of the feedstock from the annular passageway 56 into the inlets of the respective filter elements, the spacers being sealed to the centre post 41.

Various modifications and variations may be made to the embodiments described without departing from the scope of the present invention defined in the appended claims.

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Claims (10)

1. A filter element for a filter, the filter element including: a filter canister having a pair of open ends (forming respective inlets for the filter element); a centre tube located substantially coaxially within the canister; a respective filter medium within the canister, disposed about the centre tube, and adjacent a respective open end of the canister; and a flow passage defined between the filter mediums and connected to the centre tube wherein: each filter medium is wound onto the centre tube in sealing engagement with the centre tube and the wall of the canister, the wall of the canister being ribbed or otherwise profiled to deter tracking of the contaminants removed from the feedstock between the canister wall and the respective filter medium; and the feedstock passes substantially axially through the respective filter medium to the flow passage so that the filtered feedstock or filtrate will pass from the flow passage to the centre tube.

2. A filter element as claimed in claim 1 wherein the feedstock passes substantially axially through the open ends of the canister to the respective filter medium.

3. A filter element as claimed in claim 1 or claim 2 wherein: the flow passage is filled with a material with a high transverse porosity, such as woven gauze.

4. A filter element as claimed in any one of claims 1 to 3 wherein: each filter medium is a roll of facial quality paper tissue, a roll of toilet paper, or cotton, hemp, artificial or synthetic fibres or other suitable porous or foraminous material. A filter element as claimed in any one of claims 1 to 4 wherein: the filter element is disposable and is discarded once either or both of the filter mediums become fully charged with trapped and retained solids.

6. A filter for filtering of feedstock, including: a body or housing; an inlet to the housing to allow a supply of feedstock to be filtered in the HAL.'4 '1. I housing; an outlet in the housing to allow flow of filtered feedstock or filtrate from the housing; a hollow centre post, displaced coaxially within the housing, the wall of the centre post having fluid communication ports between tile outside and the thereof, the bore being connected to the housing outlet; at least one filter element as claimed in any one of clairns 1 to 5 within the housing; and filter element instali..tion means providing releasably sealable installation of the filter element(s) in the housing whereby the feedstock flows from the inlet to the outlet through the filter element(s).

7. A filter as claimed in claim 6 wherein: the housing is closed at its base and open at its top, the top being closed by a cap and fitted with sealing means to engage the wall of the housing.

8. A filter as claimed in claim 6 or claim 7 wherein: the housing inlet and the housing outlet are at the base of the housing, as is a drain port to enable contaminated feedstock to be drained from the bottom S"of the housing.

9. A filter as claimed in any one of claims 6 to 8 wherein: the open end of the (or uppermost) filter element is adjacent to the top of the housing so that at least a portion of the feedstock flows from the housing inlet up to the lid through an annular passage defined by the wall of the housing and the canister(s) of the filter element(s). A filter as claimed in any one of Claims 6 to 9 wherein: the hollow centre post is disposed within, and sealably connected to, the centre tube; and sealing means seal against the flow of fluid between the housing and the centre tube, so arranged that the filtrate in the centre tube flows through the fluid communication ports into the bore of the centre post, and then to the housing inlet.

11. A filter as claimed in Claim 10 wherein: the filter medium retaining ring is provided about the upper end of the 11 centre tube and bears against the top of the filter medium; a compression spring about the centre post is interposed between the housing cap and the retaining ring to urge the retaining ring into engagement with the filter medium to seal the upper end of the centre tube and to retain the filter medium in the canister; and a pressure knob, screw-threadably mounted on the centre post bears against one end of the centre tube to urge the filter element upwardly against the compression spring.

12. A filter as claimed in Claim 11 wherein: respective sealing means seal the centre post to the centre tube. o DATED this 10th day of July 1998 FILTER 2000 PTY LTD By their Patent Attorneys INTELLPRO r Li '3JVT 12 ABSTRACT A filter element (10) for a filter (30) has a canister (11) with a ribbed side wall (12) and is open at both ends (13, 14). A centre tube (15) has a bore (16) connected to a passage (17) via ports Woven gauze material (18) in the passage separates rolls (19, of filter medium (eg. toilet paper) wound around the centre tube (15) and in sealing engagement with the ribbed side wall (12). Fluid (eg. fuel) to be filtered can enter both ends of the element and pass through the rolls (19, so that filtered fluid passes through the passage (17) to the centre tube A *o *J