GB2203668A - Filtering apparatus - Google Patents

Abstract

Solids are removed from water by an endless moving filter belt which runs round a submerged shaft and then lifts the solids out of the water. The solids are removed from the belt by a paddle wheel 2 rotating in opposition to the belt movement, aided by a roller 1 rotating in the same direction as the wheel and receiving solids therefrom. A scraper 5 engages the roller and chute 4 directs the solids to hopper 6. The end portions of the roller may be recessed to accommodate side plates on the belt. <IMAGE>

Description

Filtering apparatus The invention relates to a self-cleaning filtering apparatus for the continuous removal of solids from a liquid flowing through a channel. Self-cleaning filtering apparatus are used in power stations and pumping stations, in sewage works and in industry for the removal from sea and river water, municipal waste waters or industrial waters of solids such as floating or suspended waste material or other solids including algae and gravel.

Self-cleaning filtering apparatus of this type according to the preamble of the main Claim are known for example from German OS 24 01 956.

In these apparatus, the waste material entrained by the endless filtering belt drops for the major part at the downstream turning point into a collecting container, in which case then the screenbelt members once more guided downwards and upstream in the channel are cleaned additionally by paddles, brushes or even by sprayed water of the waste material still adhering to the screenbelt members, which material is discharged into a collecting container by way of a chute located below the paddle.

However, during the operation of these plants it has proved disadvantageous that the waste material removed from the screenbelt members by the paddles does not drop down on the chute into the collecting hopper, but owing to the rotation of the paddle arrangement and also on account of its in many cases sticky consistency, is carried along further in the direction of the screenbelt members already cleaned and drops too late and thus drops into the purified water.

It is the object of the invention to improve these aforedescribed self-cleaning filtering plants and in particular to oppose contamination of the purified water by impurities which fall too late from the paddles or brushes.

Therefore, in order to achieve this objective, an apparatus according to the characterising part of the main Claim is proposed, in which case a particularly preferred embodiment is described in the Sub-claims.

Surprisingly it has been found that by locating a further roller below the paddle roller and offset as far as possible in the direction of the draining screen members or upstream, which can receive viscous refuse falling from the paddles, which is then guided by the roller rotating in the same direction with respect to the paddle roller back in the direction of the chute and the waste container, in which case in order to avoid further entrainment beyond the upper edge of the chute, a stripping member attached obliquely is in contact with the surface of the roller and keeps the latter clear of the waste material located on the surface.

In a particularly preferred embodiment, in its two end regions the roller has a peripheral groove, in which the corotating boundary or side plates on both sides of the screen belt may penetrate, in order that the solids dropping over the entire width of the apparatus remain on the roller and can be entrained.

The invention is described in detail hereafter with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of part of a conventional self-cleaning filtering plant with the improvement according to the invention; Figure 2 is a side view of the roller according to the invention.

The screenbelt members 7, which are shown in the present drawing solely from the downstream turning point in the cleaning bend of the screenbelt members guided vertically downwards and later guided upstream, are cleaned in the turning bend by a paddle arrangement 2, which rotates in the opposite direction to the direction of movement of the screenbelt members 7. Located below the paddle arrangement is a chute 4 receiving the impurities falling from the paddles, which chute leads into a receiving hopper 6. Located between the upper edge of the chute 4 and the paddle arrangement 2, axis parallel to the paddle shaft, is a roller 1, which in the upstream direction is moved as close as possible to the screenbelt members and is offset with respect to the paddle shaft.The roller 1 is driven by means of a chain drive 3, which is frictionally connected to the shaft supporting the paddle and the shaft 12 of the roller 1.

Also located above the chute is a stripper 5 in scraping connection with the roller 1, which stripper 5 is attached obliquely with respect to the discharge direction of the roller 1.

In the illustration of the roller 1 shown in Figure 2, a peripheral groove is respectively provided in the edge region, which groove divides the roller into a central region 10 and respectively a side region 11. The central part 10 extends below the screen members 7, whereas the side regions extend beyond the side plates 8 limiting the screenbelt. The dimensions of the groove 9 are such that the side plates 8 are accommodated. These side plates 8 serve as boundary surfaces, in order that the falling solids remain on the roller over the entire width of the screen plant and can be entrained by the latter.

The roller is preferably made from steel or synthetic material; the surface may be smooth, however, depending on the application, may preferably be produced in a ribbed, grained or grooved construction.

Due to the arrangement according to the invention,of the roller between the paddle arrangement and chute, it is possible in an elegant and inexpensive manner to collect the dirt falling too late from the paddles, by the surface of the roller 1 and once more to guide it in the direction of the chute region, where - in order to prevent further conveyance into the chamber above the purified water - it is removed by the stripper 5 from the surface of the roller and discharged by way of the chute 4 into the receiving hopper 4 or container.

Claims (5)

Claims

1. Self-cleaning filtering apparatus for the continuous removal of solids from a liquid flowing through a channel of.

given width and depth, consisting of a first shaft supported in a rotary manner across the channel in the region of the base and of a second shaft supported across the channel above the liquid level and arranged downstream with respect to the first shaft and of a plurality of filtering parts or screenbelt members connected to each other in the form of an endless belt as well as drive means, in order to allow the screenbelt members to rotate, as well as of a third shaft likewise arranged across the channel and located below the second shaft, which from the turning point or discharge point of the endless belt consisting of screen members is offset in the upstream direction and provided with stripping paddles, below which a receiving hopper or container with a chute is located, which extends below the stripping paddles, characterised in that located in the region between the upper edge of the chute (4) leading into the receiving hopper (6) and below the stripping paddle (2) is a roller (1) extending substantially over the entire width of the stripping paddle (2), which roller is on a fourth shaft extending across the channel, which fourth shaft is driven by a chain drive (3), which is connected to the third shaft, which supports the stripping paddle (2) and rotates in the same direction as the latter and that above the chute, a stripper (5) directed obliquely with respect to the direction of rotation of the roller (1) is connected to the surface of the roller (1).

2. Filtering apparatus according to Claim 1, characterised in that the fourth shaft of the roller (1) is offset in the upstream direction with respect to the third shaft and at the side facing the screenbelt members, its outer periphery lies at right angles below the rotating peripheral surface of the paddle (2).

3. Filtering apparatus according to Claims 1 and 2, characterised in that provided at both end regions of the roller (1) is a peripheral groove (9), the dimensions of which are such that the side plates (8) located on the outer ends of the screen members (7) may penetrate therein.

4. Filtering apparatus according to Claim 1, characterised in that the roller (1) consists of synthetic material or steel and has a grooved or grained surface.

5. Filtering apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.