GB2090152A

GB2090152A - Filter

Info

Publication number: GB2090152A
Application number: GB8137313A
Authority: GB
Original assignee: Henry Simon Ltd
Current assignee: Henry Simon Ltd
Priority date: 1980-12-10
Filing date: 1981-12-10
Publication date: 1982-07-07
Also published as: GB2090152B

Abstract

An upward flow filter comprises a vessel whose wall 14 has secured thereto a peripheral frame 10, above which are located projecting lips (16, Fig. 2 not shown). A flat filter module 18 is removably secured to frame 10 by ties 28 and retained thereon by the lips (16) against the upward flow of liquid. The module comprises a frame over which is stretched a sack made of polyester mesh 23, so that the liquid is filtered through two sheets of mesh in series. Felt strips 27 are sewn to the mesh to act as seals. The frame 10 and the frame of the module are made of plastics tubing. When dirty the module 18 is lifted from the vessel, washed and replaced. <IMAGE>

Description

SPECIFICATION A clarifier system This invention relates to apparatus for removing suspended solids from a liquor containing same, particularly, though not exclusively in effluent treatment plants.

A so-called clarifier system comprises an open vessel into which a liquor containing suspended solids is introduced in the lower region of the vessel, and a screen for collecting the solids is positioned in the vessel below the surface of the liquid therein, clarified liquor which appears above the screen being discharged over a weir or the like for collection. Many kinds of clarifying screen have been proposed, such as a bed of pebbles supported by a perforated deck through which the liquor passes, and the solid particles are retained by the pebbles whilst relatively clear liquor appears above the deck. From time to time, the deck is removed from the vessel for cleaning.

An object of the present invention is to provide a clarifying system of simple and inexpensive construction and including a screen which is more readily removed for cleaning than with hitherto known systems.

According to the present invention there is provided apparatus for removing suspended solids from a liquor containing same, comprising a supporting frame adapted in use to be fixed to the wall of a treatment vessel below the intended liquor level therein and providing an upper support surface for one or more removable screen modules, there being a plurality of protuberances disposed immediately above said upper support surface to locate and retain the or each screen module supported thereon, the or each said screen module comprising a pair f mesh sheets mounted in superimposed spaced apart relationship on a sub-frame, the or each module being thus readily removable for cleaning.

A clarifier system made in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which:~ Fig. 1 is a partial plan view of a supporting frame forming part of the system; Fig. 2 is a partial side elevation thereof showing the frame attached to the wall of a treatment vessel; Fig. 3 is a plan view of a sub-frame forming part of a screen module to be mounted on the supporting frame; Fig. 4 is a side elevation thereof; Fig. 5 is a plan view of a mesh sack to cover a sub-frame; Fig. 6 is a partial side elevation thereof; and Fig. 7 is a vertical section showing the manner of mounting the supporting frame and a screen module in the treatment vessel.

Referring now to the drawings, the supporting frame comprises a number of lengths of plastics tube 10, typically of the kind used for domestic rainwater goods, connected together by complementary jointing pieces 1 1, 12, 13 of a similar material, into which the tube 10 is inserted as a friction fit and, if necessary, glued or bonded, and the whole frame when assembled is attached to the wall 14 of a treatment vessel by means of harness clips 15 bolted to the wall. As can be seen from Fig. 2, at spaced positions around the main frame are a plurality of retaining lips or protuberances 16 for a purpose to be described.

Preferably, the frame includes a plurality of drain apertures 17 so that liquid cannot become trapped in the frame, and can flow freely therethrough.

The supporting frame, in use, will support a plurality of mesh screen modules which will be removably mounted on the supporting frame with their edges retained by the protuberances 16.

Referring now to Figs. 3 and 4 it will be seen that each screen module, generally indicated at 18, comprises a sub-frame made from a plurality of members 1 9 of tubular plastics material, connected together by complementary sub-frame jointing pieces 20,21 in a generally similar manner to that described in connection with the supporting frame. The members of the sub-frame are, however, of smaller cross-section and those which intersect each other are overlapped as can be seen from Fig. 4. This is partially fot simplicity of construction, but more particularly, is to ensure that the mesh sheets to be mounted on the subframe are held in spaced relationship in the central region of the module where they might otherwise tend to close together.

Referring now to Figs. 5 and 6, it will be seen that the module 18 is surrounded by a mesh sack generally indicated at 22, and comprising a pair of sheets 23 of polyester monofilament screen mesh sewn together along three of their four peripheral complementary edges by means of strips 24 of polyester tape stitched to the mesh sheets and to each other. A similar strip 25 is stitched to the fourth side of each sheet 23 and contains a number of eyelets 26 so that after the sack has been drawn over the sub-frame the ends can be closed by lacing together the eyeletted strips 25 as shown at 30. Finally, each edge of the mesh sack has stitched thereto a strip 27 of polyester needle felt which serves when the module is placed on the supporting frame, to form an effective seal around the module to prevent liquor from by-passing the latter.

In use, the screen module or modules are mounted on the supporting frame, and with reference to Fig. 6 it will be seen that this is conveniently done using polythene d;sposable tie wraps 28 at spaced intervals around each module so that these wraps can be readily cut to remove the modules for cleaning. Liquor in the vessel passes upwardly through the screen modules so that solids particles contained within the liquor are entrapped between the mesh sheets owing to the stilling effect thereof, relatively clear liquor rising through the screens for discharge over a weir (not shown) in the upper region of the vessel.

It will be appreciated that after a period of use the screen modules can be readily removed from the supporting frame for washing to remove the collected solids therefrom, the screens can then be replaced for re-use.

Claims

1. Apparatus for removing suspended solids from a liquor containing same, comprising a supporting frame adapted in use to be fixed to the wall of a treatment vessel below the intended liquor level therein and providing an upper support surface for one or more removable screen modules, there being a plurality of protuberances disposed immediately above said upper support surface to locate and retain the or each screen module supported thereon, the or each said screen module comprising a pair of mesh sheets mounted in superimposed spaced apart relationship on a sub-frame, the or each module being thus readily removable for cleaning.

2. Apparatus according to claim 1, wherein said supporting frame comprises a number of lengths of plastics tube connected together with complementary jointing pieces of a similar material into which the tube 10 is inserted.

3. Apparatus according to claim 2, wherein said lengths of tube are connected to said complementary jointing pieces and bonded thereto.

4. Apparatus according to claim 1, or claim 2, wherein said supporting frame is adapted to be attached to the walls of the treatment vessel by a plurality of spaced harness clips attached to the frame and capable of being bolted to the vessel walls.

5. Apparatus according to any preceding claim, wherein said protuberances are provided in the form of a plurality of spaced retaining lips attached to the supporting frame closely above the latter and extending outwardly from the adjacent wall surface thus to enable the edges of a module to be retained between the protuberances and the adjacent supporting surface of the frame.

6. Apparatus according to any preceding claim, wherein of the or each module said sub-frame comprises a plurality of tubular members connected together by complementary jointing pieces into which the tubular members are inserted.

7. Apparatus according to any preceding claim, wherein of the or each screen module said mesh sheets are superimposed and joined together around their edges to form a sack into which said sub-frame is inserted, said sub-frame including a pair of intersecting members which are overlapped in the central region of the module thus to ensure that said mesh sheets are held in spaced relationship in the central region of the module.

8. Apparatus according to any preceding claim, wherein each screen module includes, around at least some of its edges, strips of felt which serve, when the module is placed on the supporting frame, to form an effective seal around the module against the free passage of liquor.

9. Apparatus for removing suspended solids from a liquor containing same, substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.