GB2136308A

GB2136308A - Filter cloth construction for a filter press

Info

Publication number: GB2136308A
Application number: GB08404732A
Authority: GB
Inventors: John Thorn; Roy Gidley
Original assignee: FOTHERGILL ENGINEERED FABRICS
Current assignee: FOTHERGILL ENGINEERED FABRICS
Priority date: 1983-02-26
Filing date: 1984-02-23
Publication date: 1984-09-19
Also published as: GB8404732D0

Abstract

A filter press plate 11 carries filter cloths 12, 13 on opposite sides, and the cloths are joined together, through a slurry feed hole 15 in the plate, by an impervious tube 14. The tube 14 is of double layer impervious rubber, plastic or coated fabric, and its ends are bonded or vulcanised to respective cloths 12, 13. There is no tendency for filter cake to stick to the impervious tube 14 and no build up of filter sludge at the join of the tube 14 to the cloths 12, 13, because the join is by bonding or vulcanising and not stitching. <IMAGE>

Description

SPECIFICATION Improvements in filter press filter elements This invention relates to filter presses and in particular to improvements in filter elements thereof.

Filter elements have been proposed in which a filter cloth is secured on each side of a filter plate of the filter press by a tubular fabric passing through holes or apertures in the filter cloths and the plate and be secured to the filter cloths by the ends being expanded outwards and sewn to the filter cloths. A disadvantage of this construction is that the filter cake sticks to the tubular material and sludge builds up thereon and on the stitches.

An object of the invention is to overcome this defect so that cake and sludge do not build up on the central tube.

With this object in view the present invention provides a filter press comprising a filter plate and a filter element for each filter plate, said filter element comprising two filter face cloths arranged one on each side of the filter plate and secured thereon by means of a tube passing through holes or apertures in the filter face cloths and the filter plate and being secured to the filter face cloths by its respective ends being expanded outwards and attached to the filter face cloths, characterised in that the tube comprises an impervious material and its respective ends, which are expanded outwards, are bonded to the filter face cloths thereby preventing filter cake from sticking to material of the tube and sludge from building up on the joints between the tube and the filter face cloth.

The tube is preferably formed as a double layer material of natural rubber or neoprene or other synthetic rubber, or of plastics. Alternatively the material of the tube may be of natural rubber coated fabrics, or neoprene or other synthetic rubber coated fabrics, or other thermoplastic material such as p.v.c., e.v.a. polyethylene or polyurethane coated fabric or a thermosetting plastics material such as polyester resin or epoxy resin with a supporting fibre matrix.

The tube may be formed of strips of material wound around a former, which is subsequently removed to form the two layer tubes.

Thus the rubber or plastics material of the tube, or the neoprene or other coating which is bonded or vulcanised on a central fabric tube, is bonded or vulcanised to and through the fabric of the two filter face cloths.

The material of the tube is moulded to expand outwards to enclose the filter face cloths between the layers of the tube, which are then bonded or vulcanised to the material of the tube thereby improving the release properties of the cake and the prevention of the build up of sludge at the joints between the tube and the filter face cloths during filling of the filter press.

The invention will be described further, by way of example, with reference to the accompanying drawing in which:~ Fig. 1 is a cross-sectional plan view of part of a first preferred embodiment of the filter element of the filter press of the invention; and Fig. 2 is a view similar to that of Fig. 1 but illustrating a second preferred embodiment of the filter element of the filter press of the present invention.

Referring firstly to Fig. 1 the illustrated first preferred embodiment of the filter element 10 comprises two fabric filter face cloths 1 2 and 1 3 arranged one on each side of a filter plate 11 of a filter press. The filter face cloths 12, 13 are secured against the filter plate 1 1 by a tube 14 which pass through aligned holes or apertures indicated generally by reference numeral 15.

As can be seen from Fig. 1, the tube 14 is of a double layer material, which is impervious being, for example, rubber or synthetic rubber such as neoprene, or of plastics. The tube 14 takes the same shape as the hole or aperture in the filter plate 1 1 so that the inner surface 1 6 of the tube 14 is flat.

At its ends, the tube 14 expands outwards in order that the two layers 1 7 and 1 8 of the tube engage between a respective one of the filter face cloths 12, 13. In fact the tube 14, being either of plastics or rubber, is joined to the filter face cloths 12, 13 by being bonded or vulcanised at its ends to and through the filter face cloths 12, 13. This is advantageous over known filter elements as the absence of stitches present in the known filter elements avoids the accumulation or build up of sludge on the joints between the tube 14 and the filter face cloths 12, 1 3. Furthermore, because the tube is made of an impervious material filter cake does not stick to the tube 14 as it does in known filter elements.

Referring to Fig. 2, the second preferred embodiment of the filter element 20 is in the main identical to the filter element of Fig. 1 and therefore similar parts have been designated by the same reference numerals.

The only difference in the filter element 20 of Fig. 2 is in the shape of tube 21. It is made of the same material as the tube 14 but its two layers 22, 23 are curved outwardly, that is to say away from the holes or apertures 15 in the longitudinal direction of the filter plate 11 (i.e. as viewed in Fig.

2), matching the curved nature of the hole in the plate 11.

The tube 21 is bonded or vulcanised to the filter face cloths 12, 13 in the same manner as described in relation to the tube 14 of Fig. 1.

The invention is not confined to the precise details as aforementioned and variations may be made thereto within the scope of the invention.

Thus for example, the tube may be of a different material or different cross-sectioned shape to that described and illustrated and can be made of a material other than described so long as the material is impervious.

1. A filter press comprising a filter plate, and a filter element for each filter plate, said filter element comprising two filter face cloths arranged

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in filter press filter elements This invention relates to filter presses and in particular to improvements in filter elements thereof. Filter elements have been proposed in which a filter cloth is secured on each side of a filter plate of the filter press by a tubular fabric passing through holes or apertures in the filter cloths and the plate and be secured to the filter cloths by the ends being expanded outwards and sewn to the filter cloths. A disadvantage of this construction is that the filter cake sticks to the tubular material and sludge builds up thereon and on the stitches. An object of the invention is to overcome this defect so that cake and sludge do not build up on the central tube. With this object in view the present invention provides a filter press comprising a filter plate and a filter element for each filter plate, said filter element comprising two filter face cloths arranged one on each side of the filter plate and secured thereon by means of a tube passing through holes or apertures in the filter face cloths and the filter plate and being secured to the filter face cloths by its respective ends being expanded outwards and attached to the filter face cloths, characterised in that the tube comprises an impervious material and its respective ends, which are expanded outwards, are bonded to the filter face cloths thereby preventing filter cake from sticking to material of the tube and sludge from building up on the joints between the tube and the filter face cloth. The tube is preferably formed as a double layer material of natural rubber or neoprene or other synthetic rubber, or of plastics. Alternatively the material of the tube may be of natural rubber coated fabrics, or neoprene or other synthetic rubber coated fabrics, or other thermoplastic material such as p.v.c., e.v.a. polyethylene or polyurethane coated fabric or a thermosetting plastics material such as polyester resin or epoxy resin with a supporting fibre matrix. The tube may be formed of strips of material wound around a former, which is subsequently removed to form the two layer tubes. Thus the rubber or plastics material of the tube, or the neoprene or other coating which is bonded or vulcanised on a central fabric tube, is bonded or vulcanised to and through the fabric of the two filter face cloths. The material of the tube is moulded to expand outwards to enclose the filter face cloths between the layers of the tube, which are then bonded or vulcanised to the material of the tube thereby improving the release properties of the cake and the prevention of the build up of sludge at the joints between the tube and the filter face cloths during filling of the filter press. The invention will be described further, by way of example, with reference to the accompanying drawing in which:~ Fig. 1 is a cross-sectional plan view of part of a first preferred embodiment of the filter element of the filter press of the invention; and Fig. 2 is a view similar to that of Fig. 1 but illustrating a second preferred embodiment of the filter element of the filter press of the present invention. Referring firstly to Fig. 1 the illustrated first preferred embodiment of the filter element 10 comprises two fabric filter face cloths 1 2 and 1 3 arranged one on each side of a filter plate 11 of a filter press. The filter face cloths 12, 13 are secured against the filter plate 1 1 by a tube 14 which pass through aligned holes or apertures indicated generally by reference numeral 15. As can be seen from Fig. 1, the tube 14 is of a double layer material, which is impervious being, for example, rubber or synthetic rubber such as neoprene, or of plastics. The tube 14 takes the same shape as the hole or aperture in the filter plate 1 1 so that the inner surface 1 6 of the tube 14 is flat. At its ends, the tube 14 expands outwards in order that the two layers 1 7 and 1 8 of the tube engage between a respective one of the filter face cloths 12, 13. In fact the tube 14, being either of plastics or rubber, is joined to the filter face cloths 12, 13 by being bonded or vulcanised at its ends to and through the filter face cloths 12, 13. This is advantageous over known filter elements as the absence of stitches present in the known filter elements avoids the accumulation or build up of sludge on the joints between the tube 14 and the filter face cloths 12, 1 3. Furthermore, because the tube is made of an impervious material filter cake does not stick to the tube 14 as it does in known filter elements. Referring to Fig. 2, the second preferred embodiment of the filter element 20 is in the main identical to the filter element of Fig. 1 and therefore similar parts have been designated by the same reference numerals. The only difference in the filter element 20 of Fig. 2 is in the shape of tube 21. It is made of the same material as the tube 14 but its two layers 22, 23 are curved outwardly, that is to say away from the holes or apertures 15 in the longitudinal direction of the filter plate 11 (i.e. as viewed in Fig. 2), matching the curved nature of the hole in the plate 11. The tube 21 is bonded or vulcanised to the filter face cloths 12, 13 in the same manner as described in relation to the tube 14 of Fig. 1. The invention is not confined to the precise details as aforementioned and variations may be made thereto within the scope of the invention. Thus for example, the tube may be of a different material or different cross-sectioned shape to that described and illustrated and can be made of a material other than described so long as the material is impervious. CLAIMS

1. A filter press comprising a filter plate, and a filter element for each filter plate, said filter element comprising two filter face cloths arranged one on each side of the filter plate and secured thereon by means of a tube passing through holes or apertures in the filter face cloths and the filter plate and being secured to the filter face cloths by its respective ends being expanded outwards and attached to the filter face cloths, characterised in that the tube comprises an impervious material and its respective ends, which are expanded outwards, are bonded to the filter face cloths thereby preventing filter cake from sticking to the material of the tube and sludge from building up on the joints between the tube and the filter face cloth.

2. A filter press as claimed in claim 1 wherein the tube is formed as a double layer material.

3. A filter press as claimed in claim 1 or 2 wherein the tube material is natural rubber or neoprene or other synthetic rubber.

4. A filter press as claimed in claim 1 or 2 wherein the tube material is plastics.

5. A filter press as claimed in claim 1 or 2 wherein the tube is of natural, or neoprene or other synthetic rubber coated fabric.

6. A filter press as claimed in claim 1 or 2 wherein the tube is of thermoplastic material such as p.v.c., e.v.a. polyethylene or polyurethane coated fabric or a thermosetting plastics material such as polyester resin or epoxy resin with a supporting fibre matrix.

7. A filter press as claimed in any one of claims 2 to 6 wherein the tube is formed of strips of material wound around a former, which is subsequently removed to form the two layer tube.

8. A filter press as claimed in any one of claims 2 to 7 wherein the material of the tube is moulded to expand outwards to enclose the filter face cloths between the layers of the tube.

9. A filter press as claimed in any preceding claim wherein the material of the tube is bonded or vulcanised to and through the fabric of the two filter face cloths.

10. A filter press substantially as hereinbefore described with reference to and as illustrated in Fig. 1, or in Fig. 2 of the accompanying drawing.