GB2029718A

GB2029718A - Rotary vacuum disc filters

Info

Publication number: GB2029718A
Application number: GB7836469A
Authority: GB
Original assignee: Simonacco Ltd
Current assignee: Simonacco Ltd
Priority date: 1978-09-12
Filing date: 1978-09-12
Publication date: 1980-03-26
Also published as: ZA793827B; AU5006879A; GB2029718B

Abstract

A sector for a disc of a rotary vacuum disc filter comprises a framework (10, 11) faced with a pair of fluted and perforated sectorial plates (13) each overlaid with an individual sheet of filter cloth (17), the sheets being removably attached to the sector along its side and end edge regions by means of two-part touch and close fasteners, one part (14) of each fastener being attached by tacking or adhesive to the framework and/or the plates and the other part being attached to the filter cloth by stitching or adhesive. <IMAGE>

Description

SPECIFICATION Improvements in rotary vacuum disc filters This invention relates to rotary vacuum disc filters of the kind comprising one or more filtering discs mounted in axially spaced relationship on a hollow driven shaft, each disc consisting of a plurality of discrete sectors of hollow construction each supporting filter cloth, and, during rotation of the shaft, becoming partially submerged in a bath of slurry to be filtered. Suction applied sequentially within the sectors via the driven shaft causes liquid to be drawn through the filtering surfaces, leaving a solids deposit thereon for removal by applying a reverse flow of liquid or air through the filter cloth.

It has been normal practice for each discrete sector to be provided with a sack of filter cloth which, when the sector is removed from its associated disc, can be placed around the sector and fixed thereto. In operation, the filter sacks are often subjected to severe abrasive treatment from the slurry being filtered, and this necessitates frequent replacement of sacks when the filter cloth therefore becomes torn. Of course, the replacement of a filter sack involves an expensive and time-consuming procedure during which time the disc filter is usually inoperable, and this may be necessary as a result of a single small tear in one part of the filter cloth of one sector.

An object of the present invention is to provide means by which replacement of the filter cloth of a disc filter sector can be carried out more rapidly and at considerably less cost than has been the case hitherto.

Thus according to the present invention, there is provided a sector for a disc of a rotary vacuum disc filter, the sector comprising a framework supporting a pairoffluted and perforated sectorial plates disposed on opposite faces of the framework and overlaid with filter cloth, characterised in that to the peripheral edge regions of the sector, before the filter cloth, there are attached strips comprising, in each case one part of a two-part touch and close fastener, the other part being attached to a sheet of filter cloth around the edge regions thereof, whereby the latter can be applied readily to the sector to constitute the filtering surfaces thereof, by bringing together the parts of the fastener, and as readily can be removed and replaced when necessary.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:~ Fig. 1 is a part-sectional view of a filter disc sector made in accordance with the invention; Fig. 2 is a section taken on line Il-I I of Fig. 1; and Fig. 3 is a section taken on line Ill-Ill of Fig. 1.

With particular reference to the drawings, the sector to be described comprises a framework consisting essentially of a plurality of generally radial members 10 and a circumferential stringer 1 1 at the wider end of the sector. At the narrow end of the sector the framework is attached to a nozzle 12 by which the sector may be connected to a duct extending through a driven shaft which carries the discs in axially spaced relationship.

The framework supports a pair of fluted and perforated sectorial plates 13 disposed on opposite faces of the sector.

Extending along substantially the entire length of the outer frame members 10 constituting the radial sides of the sector, are strips 1 4 forming, in each case, one part of a two-part touch and close fastener, for example, of the kind manufactured and sold under the Registered Trade Mark VELCRO. Further strips of the same part of the fastener are attached to the stringer 1 1 and the face of each plate 13, at the wider and narrower ends of the sector respectively, as indicated at 15 and 16. The strips 14, 15 and 16 may be attached to their respective parts of the sector by tacks, or alternatively may be attached thereto by an adhesive.

The filtering surfaces of the sector are provided by a pair of separate sheets 1 7 of filter cloth which, as can be seen from Figs. 2 and 3, carry around their edge regions the other halves of the fastener which correspond to the strips 14, 1 5 and 16. These strips, two of which are illustrated at 1 4a and 1 5a are preferably stitched to the filter cloth, or may be attached thereto by an adhesive.

It can be seen therefore that when one of the sheets of filter cloth becomes damaged in use, it can readily be removed by separating the two parts of the fastener around the sector, and can be replaced by a new sheet having similar strips of fastener which can readily be applied to the parts 14, 1 5 and 1 6 of the fastener which have remained on the sector.

In the embodiment shown in the drawings, it is necessary to remove the sector from the disc in order to replace a filter cloth, as the strips 14, 1 4a and 15, 1 5a are folded over the edges of the sector as illustrated in Figs. 2 and 3, and, in the case of the strips 14, 1 4a, are thus trapped between abutting side edges of adjacent sectors.

As an alternative arrangement, it may be appropriate in some cases for the strips 14 and 1 5 to be attached along the faces of the plates 13 as is strip 16, thus obviating the need to remove the sector from the disc for replacement of the filter cloth.

1. A sector for a disc of a rotary vacuum disc filter, the sector comprising a framework supporting a pair of fluted and perforated sectorial plates disposed on opposite faces of the framework and overlaid with filter cloth, characterised in that to the peripheral edge regions of the sector, before the filter cloth, there are attached strips comprising, in each case, one part of a two-part touch and close fastener, the other part being attached to a sheet of filter cloth around the edge regions thereof, whereby the latter can be applied readily to the sector to constitute the filtering surfaces thereof, by

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in rotary vacuum disc filters This invention relates to rotary vacuum disc filters of the kind comprising one or more filtering discs mounted in axially spaced relationship on a hollow driven shaft, each disc consisting of a plurality of discrete sectors of hollow construction each supporting filter cloth, and, during rotation of the shaft, becoming partially submerged in a bath of slurry to be filtered. Suction applied sequentially within the sectors via the driven shaft causes liquid to be drawn through the filtering surfaces, leaving a solids deposit thereon for removal by applying a reverse flow of liquid or air through the filter cloth. It has been normal practice for each discrete sector to be provided with a sack of filter cloth which, when the sector is removed from its associated disc, can be placed around the sector and fixed thereto. In operation, the filter sacks are often subjected to severe abrasive treatment from the slurry being filtered, and this necessitates frequent replacement of sacks when the filter cloth therefore becomes torn. Of course, the replacement of a filter sack involves an expensive and time-consuming procedure during which time the disc filter is usually inoperable, and this may be necessary as a result of a single small tear in one part of the filter cloth of one sector. An object of the present invention is to provide means by which replacement of the filter cloth of a disc filter sector can be carried out more rapidly and at considerably less cost than has been the case hitherto. Thus according to the present invention, there is provided a sector for a disc of a rotary vacuum disc filter, the sector comprising a framework supporting a pairoffluted and perforated sectorial plates disposed on opposite faces of the framework and overlaid with filter cloth, characterised in that to the peripheral edge regions of the sector, before the filter cloth, there are attached strips comprising, in each case one part of a two-part touch and close fastener, the other part being attached to a sheet of filter cloth around the edge regions thereof, whereby the latter can be applied readily to the sector to constitute the filtering surfaces thereof, by bringing together the parts of the fastener, and as readily can be removed and replaced when necessary. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:~ Fig. 1 is a part-sectional view of a filter disc sector made in accordance with the invention; Fig. 2 is a section taken on line Il-I I of Fig. 1; and Fig. 3 is a section taken on line Ill-Ill of Fig. 1. With particular reference to the drawings, the sector to be described comprises a framework consisting essentially of a plurality of generally radial members 10 and a circumferential stringer 1 1 at the wider end of the sector. At the narrow end of the sector the framework is attached to a nozzle 12 by which the sector may be connected to a duct extending through a driven shaft which carries the discs in axially spaced relationship. The framework supports a pair of fluted and perforated sectorial plates 13 disposed on opposite faces of the sector. Extending along substantially the entire length of the outer frame members 10 constituting the radial sides of the sector, are strips 1 4 forming, in each case, one part of a two-part touch and close fastener, for example, of the kind manufactured and sold under the Registered Trade Mark VELCRO. Further strips of the same part of the fastener are attached to the stringer 1 1 and the face of each plate 13, at the wider and narrower ends of the sector respectively, as indicated at 15 and 16. The strips 14, 15 and 16 may be attached to their respective parts of the sector by tacks, or alternatively may be attached thereto by an adhesive. The filtering surfaces of the sector are provided by a pair of separate sheets 1 7 of filter cloth which, as can be seen from Figs. 2 and 3, carry around their edge regions the other halves of the fastener which correspond to the strips 14, 1 5 and 16. These strips, two of which are illustrated at 1 4a and 1 5a are preferably stitched to the filter cloth, or may be attached thereto by an adhesive. It can be seen therefore that when one of the sheets of filter cloth becomes damaged in use, it can readily be removed by separating the two parts of the fastener around the sector, and can be replaced by a new sheet having similar strips of fastener which can readily be applied to the parts 14, 1 5 and 1 6 of the fastener which have remained on the sector. In the embodiment shown in the drawings, it is necessary to remove the sector from the disc in order to replace a filter cloth, as the strips 14, 1 4a and 15, 1 5a are folded over the edges of the sector as illustrated in Figs. 2 and 3, and, in the case of the strips 14, 1 4a, are thus trapped between abutting side edges of adjacent sectors. As an alternative arrangement, it may be appropriate in some cases for the strips 14 and 1 5 to be attached along the faces of the plates 13 as is strip 16, thus obviating the need to remove the sector from the disc for replacement of the filter cloth. CLAIMS

1. A sector for a disc of a rotary vacuum disc filter, the sector comprising a framework supporting a pair of fluted and perforated sectorial plates disposed on opposite faces of the framework and overlaid with filter cloth, characterised in that to the peripheral edge regions of the sector, before the filter cloth, there are attached strips comprising, in each case, one part of a two-part touch and close fastener, the other part being attached to a sheet of filter cloth around the edge regions thereof, whereby the latter can be applied readily to the sector to constitute the filtering surfaces thereof, by bringing together the parts of the fastener, and as readily can be removed and replaced when necessary.

2. A sector according to claim 1 , wherein said one part of said fastener is attached to and extends along substantially the entire length of each side edge of the sector and around the edge of the wider end thereof, and extends across each face of the sector in the narrower end region thereof.

3. A sector according to claim 1, wherein the said one part of said fastener is attached to each face of the sector along the sides and wider end regions thereof, and across the faces in the narrow end region of the sector.

4. A sector according to any one of the preceding claims, wherein the said one part of the said fastener is attached to the sector by tacks.

5. A sector according to any one of the preceding claims, wherein said other part of said fastener is attached around the edge regions of each sheet of filter cloth, by stitching.

6. A sector according to any one of claims 1 to 3, wherein said two parts of said fastener are attached to their respective parts of the sector by an adhesive.

7. A sector according to any one of the preceding claims, wherein said two-part touch and close fastener is of the kind manufactured and sold under the Registered Trade Mark VELCRO.

8. A sector for a disc of a rotary vacuum disc filter, substantially as hereinbefore described, with reference to, and as illustrated in, the accompanying drawings.