GB2104402A

GB2104402A - Apparatus for removing solid material from sewage

Info

Publication number: GB2104402A
Application number: GB08222690A
Authority: GB
Inventors: Reginald Albert Edward Wilson
Original assignee: Jones and Attwood Ltd
Current assignee: Jones and Attwood Ltd
Priority date: 1981-08-11
Filing date: 1982-08-06
Publication date: 1983-03-09

Abstract

Sewage flows out of a duct 10 through a rotary cylindrical primary screen (11), from which retained solids are removed by a scraper (13) or brush and delivered to a secondary bar screen (14), which is in turn cleaned by combs (17) carried between endless chains or an an endless band. The solids may then pass from trough (20) to a press (not shown). <IMAGE>

Description

SPECIFICATION Apparatus for removing solid material from sewage or other liquid This invention relates to apparatus for removing solid material from a flow of sewage or other material and has as its object the provision of such apparatus in an improved form.

In accordance with this invention there is provided apparatus for removing solid material from a flow of sewage or other liquid, said apparatus comprising a duct through which sewage or other liquid is to flow, at least one primary screen located in said duct and adapted to filter material from the sewage or other liquid flowing through the duct, means for removing said solid material from primary screen, a secondary screen located in said duct and arranged to intercept solid material removed from primary screen or screens and an endless scraper member which is moveable relative to said secondary screen and which has scraper means arranged during such movement to pass along the secondary screen in order in use to remove solid material intercepted thereby.

The Secondary screen may comprise a plurlality of stationary spaced bars which extend in a generally vertical direction over the major part of their length and the endless scraper member may comprise an endless chain or endless band which is provided with a plurality of projecting tines which are arranged, on actuation of said scraper member, to extend during part of their travel, between the bars of said secondary screen so as to remove solid material intercepted thereby. Such removed material may then be delivered to a waste collection chute or trough or to a conveyor, the removed material conveniently passing in all cases to a screenings press in which the material is compressed and liquid expelled therefrom.

The invention will now be more particularly described with reference to the accompanying drawings wherein; Figure 1 is a schematic side view of one example of apparatus in accordance with the invention, Figure 2 is a schematic plan view of the apparatus seen in Fig. 1.

Figure 3 is a schematic plan view showing in part an alternative form of means for removing solid material from the primary screen seen in the apparatus shown in Figs 1 and 2, and Figure 4 is a schematic lay-out in plan view of a plant incorporating apparatus in accordance with the invention.

Referring now to the drawings, Fig. 1 shows in schematic form a side view of one example of apparatus constructed in accor dance with the invention, said apparatus be ing intended for use in removing solids from a flow of sewage or other liquid and to this end there is provided a duct 10 through which said sewage or liquid will flow. Mounted within said duct is provided at least one primary screen 11 in the form of a rotatable cylindrical drum which is arranged so that its axis extends vertically and which in use would be connected to an electric motor (not shown) by means of which the screen can be rotated.

The screen is provided with a plurality of apertures 12 through which liquid and finely suspended solids can pass to the interior of the screen from whence it flows through a further duct (not shown) for additional treatment. Larger pieces of solid material do not of course pass through said apertures 12 and such solid material is removed from the exterior of the or each primary screen 11 by means which in the example shown in Figs. 1 and 2 comprises one or more stationary scraper bars or blades, one such scraper bar or blade being indicated by reference number 13 in Figs. 1 and 2.

There is also provided a secondary screen 1 4 which comprises a plurality of stationary spaced bars 15 extending over the major part of their length in a generally vertical direction, the upper part of said bars 15 being, however, bent to provide a horizontal section which is in turn bent again to form a short vertical section 1 spa. As shown in Fig. 2 solid material which will be removed from the primary screen 11 by said scraper bar or bars 13 will be intercepted by the secondary screen 14 and accordingly there are also provided means for scraping such solid material from the secondary screen. Said scraping means comprises an endless scraper member 16 in the form of an endless chain or other form of endless band which is provided at spaced intervals with a plurality of outwardly projecting tines 17.Said endless scraper member 16 is disposed on that side of the vertical part of the secondary screen 14 which is remote from the primary screen 11 and means such as a electric motor (generally indicated by reference numeral 18) is provided for rotating the endless chain 16, the lower end of said chain passing round a sprocket wheel or pulley 19 and the chain being further guided by other sprocket wheels 8 and 9. As will be seen from Fig. 1 the tines 17 during a part of their travel will extend between the bars 15 of the secondary screen 1 4 and will traverse along the length thereof as said endless face thereof adjacent to the primary screen 11.At the chain 16 is rotated, thus removing solid material that has been intercepted by said secondary screen on that lower end of the secondary screen 14 is a deflector 7 which will direct that part of the material not immediately intercepted by the secondary screen so that such material can pass beneath said screen and then be recirculated.

There is also provided a waste collection chute or trough 20 arranged above the duct 10 and below the short vertical section 1 5a of the secondary screen 14 so that solid material which has been removed from said secondary screen will eventually be deposited in said chute or trough 20. Conveniently a flow of water is passed through said trough to remove accumulated solid material which can then be delivered to a screenings press (not shown) where it can be compressed and subsequently disposed of.

In the above-described arrangement of Figs 1 and 2 one or more scraper bars or blades 1 3 are used to remove solid material from the exterior of the rotating primary screen 11. In an alternative arrangement however, as shown in Fig. 3, such solid material may be removed from the exterior of the rotating primary screen 11 by means of a rotatable brush 21 which is also driven by an electric motor (not shown) so that it rotates in the same direction as the direction of rotation of the primary screen 11. The inter-engaging surfaces of the primary screen 11 and the rotating brush 21 will thus move in opposite directions. Solid material thus removed from the exterior of the primary screen 11 will however pass to a secondary screen 14 which is constructed as generally described with reference to the construction shown in Figs. 1 and 2.

Apparatus as described above either with reference to Figs. 1 and 2, or with reference to Fig. 3, may be arranged to deliver solid material to a trough or chute 20 which also received solid material from a plurality of similar installations so that a relatively large flow of sewage or other liquid can readily be dealt with. In an alternative lay-out however, as illustrated in Fig. 4, the duct 10 is provided with a pair of rotatable primary screens 11 and, as shown, each of these screens is provided with scraping means in the form of a rotatable brush 21 for removing solid material from its exterior. There is also provided adjacent to the upstream primary screen a deflector 22 which can be adjusted about a vertical axis and which is used to deflect the flow of sewage which does not pass into the interior of the upstream screen 11.In this layout therefore the secondary screen 14 will intercept and collect solid material removed from both of the primary screens 11 and will, as explained above, discharge such solid material eventually into a waste collection chute or trough. As an alternative, both of said primary screens may each be provided with a scraper bar 13 instead of a rotatable brush 21 for removing solid material from their exteriors and in yet a further alternative one primary screen may be provided with a scraper bar and the other with a rotatable brush. Furthermore a conveyor can be used instead of a chute or trough 20 to remove the solid material intercepted by the secondary screen.

It will be appreciated that with the present invention a single screenings press can be used to compress the solid material which is removed by the secondary screen (which itself may serve two or more primary screens) or, where more than one secondary screen is employed, a plurality of secondary screens.

Claims

1. Apparatus for removing solid material from a flow of sewage or other liquid, said apparatus comprising a duct through which sewage or other liquid is to flow, at least one primary screen located in said duct and adapted to filter solid material from the sewage or other liquid flowing through the duct, means for removing said solid material from said primary screen, a secondary screen located in said duct and arranged to intercept solid material removed from said primary screen or screens and an endless scraper member which is moveable relative to said secondary screen in order to remove solid material intercepted thereby.

2. Apparatus as claimed in Claim 1 wherein the or each primary screen comprises a rotatable cylindrical screen.

3. Apparatus as claimed in Claim 2 or Claim 2 wherein said means for removing solid material from the or each primary screen comprises one or more stationary scraper bars or blades.

4. Apparatus as claimed in Claim 1 or Claim 2 wherein said means in removing solid material from the or each primary screen comprises one or more rotatable brushes.

5. Apparatus as claimed in any one of the preceding claims wherein the secondary screen comprise a plurality of stationary spaced bars which extend in a generally vertical direction over the major part of their length, said endless scraper member comprising an endless chain or endless band which is provided with a plurality of projecting tines which are arranged, on actuation of said scraper member, to extend, during a part of their travel, between the bars of said secondary screen so as to remove solid material interrupted thereby.

6. Apparatus as claimed in Claim 5 wherein the upper ends of secondary screen bars are extended and bent over and downwardly in a direction away from the primary screen.

8. Apparatus as claimed in any one of the preceding claims wherein there is provided one screenings press for use in compressing solid material removed from the or each secondary screen.

9. Apparatus for removing solid material from a flow of sewage or other liquid, said apparatus being substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2, or Figs. 3, or Fig. 4 to the accompanying drawings.

CLAIMS (6 Oct 1982)

7. Apparatus as claimed in any one of the preceding claims wherein there are provided two or more primary screens and one secondary screen.