GB2185696A

GB2185696A - Filter stack

Info

Publication number: GB2185696A
Application number: GB08701621A
Authority: GB
Inventors: Roger John Temple
Original assignee: FLOWTECH FLUID HANDLING LIMITE
Current assignee: FLOWTECH FLUID HANDLING LIMITE
Priority date: 1986-01-28
Filing date: 1987-01-26
Publication date: 1987-07-29
Anticipated expiration: 2007-01-26
Also published as: GB8601966D0; GB2185696B; GB8701621D0

Abstract

Adjacent filter discs (2) of adjacent filter elements (1) of hollow disc form stacked in a filter cartridge are maintained in separation by a separator element (15) having an annular seal portion (14) and radial spokes extending outwardly therefrom to an edge seal (5) connecting the filter discs (2) of an element (1). The separator element (25) can instead be independent of either cell (Figs. 3,4). <IMAGE>

Description

SPECIFICATION Filter apparatus The invention relates to a filter apparatus and to a separator element for use in a filter apparatus.

Known filter apparatus comprises a filter cartridge constituted by a stack of individual filter cells, each comprising a pair of sheet-like filter elements, for example of square or circular shape, sealingly connected together attheirouter edges, with a spacer element enclosed between them. The sheet material ofthefilterelements maybe made from a slurry ofcellulosicfibre, and the spacer element between them can be moulded of a suitable plastics material. The spacer element has a central aperture which co-operates with central apertures provided in the filter elements to form a discharge passage. The cells of the cartridge are held in the axially stacked relationship, with sealing rings between them, by stainless steel strips, and are received within a filter housing.The fluid to be filtered passes from the outsides of the cells through the filter elements, and the filtrate is discharged through a fluid discharge tube communicating with the common discharge passage of the cells. Contaminants are deposited on the outsides of the filter elements.

In the known filter cartridges of this kind, the filter elements of the filter cells are liable to distortion in use, when the elements are saturated with liquid and subjected to external pressure applied by the fluid to be filtered, and there can result contact between the outer surfaces of the filter elements of adjacent cells, which is disadvantageous in that it reduces the effective area of the filter elements which is exposed tothefluid.

The present invention is concerned with the provision of means whereby this disadvantage can be overcome.

The invention accordingly provides a separator device for use between adjacentfilter cells in a filter cartridge, each cell being ofthe kind having a pairof apertured filter elements sealingly connected togetherattheirouteredgeswith a spacer elements enclosed between them, the separator element of the invention being arranged to maintain apartthe outer surfaces ofadjacentfilterelementsofthe adjacent cells.

The separator device of the invention can comprise a seal portion for extending around the aperture of a filter element, and spacer means extending outwardly of the seal portion for spacing the filter elementfrom the adjacentfilter element of the adjacent cell.

The spacer means can conveniently comprise a plurality of limbs radiating from the annular seal portion, each limb having an undersurface engageable with the filter element and an outer surface configuration engageable with the opposed filter element, or with the like configuration of a seal device of the adjacentfilter cell. The or each surface of the limb engaging the filter element preferably has a shape and area such asto minimisethepossibility of damage to the element, whilst not unduly restricting the area of the element exposed to the fluid to be filtered. The spacing configurations are preferably located a substantial distance outwardly from the seal portion.

The seal device of the invention can be a component of the filter cartridge separate from the filter cells, and arranged to be placed between adjacent cells when the cartridge is assembled. The separator device can instead be a part of each filter cell as manufactured. The limbs of the separator device can then extend outwardly from the annular seal portion to the edge seal at the outer peripheries of the filter elements, or inwardlyfrom this edge seal, so asto be an inseparable part of the cell.The seal devicethenfunctions also to reinforcethe structure of the cell, to prevent rupture of the filter elements and separation of the edge seal, as can sometimes occur during removal of a cartridge, when the elements are saturated with liquid and weakened by distortion underthe pressures experienced bythecells.

The invention thus also provides a filter cell ofthe kind described having on the outer side of at least one of the filter elements a ring around the filter element aperture and spacer means extending from the ring to the edge connection at which the spacer means is secured.

The invention isfurther described below, byway of illustration, with reference to the accompanying drawings, in which: Figure 1 is a partial cross-sectional side view of a filter cell with a seal or separator device in accordance with the invention; Figure 2 is a partial plan view of the filter cell and seal device of Figure 1; Figure 3 is a partial sectional side view of a seal or separator device located in accordance with the invention between filter discs of two adjacent filter cells; and Figure 4 is a partial plan viewofthe seal device shown in Figure 4.

The filter cell 1 shown in Figure 1 comprisestwo like filter elements in the form of annular filter discs 2. The material of the filter discs 2 can be of any appropriate kind, for example, the discs can be made from a slurry of cellulosic fibre in which particulate filter material can be included. The filter discs 2 have compressed flange portions 4 attheirouter peripheral edges, at which the sheets are sealingly connected. This peripheral connection is effected by means of an edge seal 5 of plastics material, preferably polypropylene, which is moulded onto the compressed flange portions 4 to hold them sealinglytogether.

Trapped between the two filter discs 2 is a spacer element6 of generally annular form, with a central aperture 7 corresponding to the central apertures 9 of the two filter discs. The spacer element is integrally moulded of suitable plastics material, for example, polypropylene, and comprises a plurality of circular concentric ribs 10 connected together by a plurality of radially extending arms 9. The ribs 10 prevent the inner faces of the filter discs 2 from being forced together into contact in use of the filter cell 1, by excess external pressure, to avoid reduction of the effective filter area. In place of the spacer element 6, a spacer element as described in Application 8601 965, the contents of which are incorporated herein by reference, can be incorporated in the cell 1.

The outer side of each filter disc 2 is engaged around the edge of the aperture 9 by an annularseal portion 14 of a separator device 15 having a plurality of limbs 16 radiating out from the annular portion to the edge seal 5. The annular portion 14 is provided with concentric circular ridges on the surface presented to the filter disc 2,to ensure a good seal with this disc.

The limbs 16, of which four or any other suitable numbercan be provided, haveaflatundersurfaceto engagedthefilterdiscand are shaped to followthe shape of the filter disc 2 and the flange portions 4at its outer edge. The extreme outer end of each limb 16 extends into the seal edge 5 so as to be securely held in place bythe moulding of the seal edge onto the flange portions 4 during assembly of the cell. The limbs 16, which can be of generally rectangular cross-section have relatively thick inner portions 17 separated by a step from substantially thinner outer portions 19.

The upper part of Figure 1 shows the upper separator device 15 of the filter cell 1 in engagement in a filter cartridge with the lower separator device of a super-adjacentfiltercell identical to the cell 1. The outerfaces ofthetwo annular seal portions 14 effect a seal between the two cells, and the thicker portions 17 of the radially extending limbs 16, which are placed in alignment when the two cells are assembled together, come into abutment so as to space apart the adjacent filter discs 2 of the two cells.

In Figures 3 and 4, spacing apart of the filter discs 2 of two adjacentfilter cells 1 in a filter cartridge is effected by a seal device 25 of the invention which is secured to neither cell. The seal device 25 again comprises an annular seal portion 24from which four or other suitable number of limbs 26 radially extend. The seal portion 24 is provided on both sides with concentric ridges for engaging the material of the filter discs around the apertures 9, and the limbs, which can be of rectangular cross-section, extends outwardly a sufficient distance to provide the required spacing between the two filter discs 2.

The invention can also be embodied as a separator device which resembles that of Figures 3 and 4 in having an annular portion with concentric seal ridges on both sides, but which resembles that of Figures 1 and 2 in having radiating limbs extending to the seal edge and being secured therein. Such a device is provided on only one side of each filter cell, the seal and spacing meansforthefilterdisconthe other side ofthe cell being provided by a similar seal device on the adjacent cell of the cartridge.

The deviceofthe invention, however embodied, can be integrally moulded in plastics material, for example polypropylene.

As will be evident, the invention can be embodied in a variety of ways other than as specifically described and illustrated.

Claims

1. Aseparatorelementformaintaining separation between adjacent filter discs of adjacent filter cells in a filter cartridge, each cell having two apertured filter discs sealed together atthe outer edgesthereofand spaced apartinternally,the separator element comprising an apertured portion for reception between the adjacent cells in the region ofthe apertures of the filter discs, and separator portions extend outwardly from the apertured portion.

2. A separator element as claimed in claim 1 wherein the aperture of the apertured portion corresponds to that of the filter discs for alignment therewith.

3. A separator element as claimed in claim 1 or 2 wherein the apertured portion is arranged to seal on at least one side thereof with the adjacent filter disc.

4. A separator element as claimed in claim 3 wherein the apertured portion has concentric ridges on the at least one side for sealing engagement with the adjacent filter disc.

5. A separator element as claimed in claim 1,2,3 or 4wherein the separator portions comprise at lest four angularly spaced arms extending from the apertured portion.

6. A separator element as claimed in any preceding claim, the element being integrally moulded in plastics material.

7. A separator element substantially as herein described with reference to Figures 3 and 4 of the accompanying drawing.

8. Afilter cartridge comprising a stack offilter cells, each cell having filter discs peripherally sealed together and spaced apart internally, and a separator element received between each adjacent pair of filter cells,theseparatorelement being arranged to maintain separation between adjacentfilter discs of the adjacentfiltercells.

9. Afilter cartridge as claimed in claim 8wherein the or each separator is as claimed in any one of claims 1-7.

10. Afilter cell comprising two centrally apertured filter discs peripherally sealed together and internally spaced apart, and a separator element sclaimed in any one of claims 1 to 7 secured to at least one side of the filter cell.

11. Afilter cell for stacking with one or more like filter cells to form a filter cartridge, the filter cell comprising two centrally apertured filter discs connected together atthe outer edges thereof and internally spaced apart, and a separator element located externally of at least one of the discs for separating the discfrom the adjacent disc of an adjacent like filter cell in a filter cartridge.

12. Afiltercell as claimed in claim 10 or 11 wherein the separator element comprises an annular portion around the central aperture of the adjacent filter disc and separator portions extending outwardlyfromtheannularportion.

13. Afiltercell as claimed in claim 12 wherein the separator portions of the separatorextendto and are secured at the outer edge seal of the filter discs.

14. Aseparator element as claimed in claim 12 or 13 wherein the annular portion is arranged to seal on at least one side thereof with the adjacent filter disc.

15. A separator element as claimed in claim 14 wherein the annular portion has concentric ridges on the at least one side for sealing engagement with the adjacent filter disc.

16. A separator element as claimed in claim 12, 13,14 or 15 wherein the separator portions comprise angularly spaced arms extending from the annular portion.

17. Afilter cell substantially as herein described with reference to Figures 1 and 2 ofthe accompanying drawing.