IL43598A - Method and device for compacting fluid sludge - Google Patents

Claims (1)

43598-2 What we claim is:- 1. A method of compacting fluid sludge which comprises flakes of matter in a carrier liquid and which has undergone flocculation treatment to agglomerate particles of the matter into said flakes, the method comprising the steps of introducing the sludge into an upper portion of .the tank- mechanically stirring the sludge in the upper portion of the tank such that said flakes combine to form large flakes which fall towards the bottom of the tank; and mechanically pressing the fallen flakes in a lower portion of the tank towards a discharge orifice of the tank thereby to compress the flakes into a compact mass for discharge through said orifice whilst the carrier liquid from between the flakes rises towards the top of the tank. 2. Apparatus for compacting fluid sludge which comprises flakes of matter in a carrier liquid nd which has undergone floccmla ion treatment to agglomerate particles of the matter into said flakes, wherein the apparatus comprises : a tank w.'iich is provided at an upper portion with an inlet for the sludge and at a lower portion with a discharge orifice; mechanical stirring means for stirring the sludge in the upper portion of the tank such that said flakes combine to form ¾¾@er flakes which fall towards the bottom of the tank; mechanical pressing means for pressing fallen flakes in the lower portion of the tank towards said orifice thereby to compress the flakes into a compact m ss and for discharge through the orifice;^/an overflow system at the top of the tank for the removal of carrier liquid which has been separated from said flakes; and wherein the lower portion 43598-2 portion; the pressing means comprises, for the or each conical portion, a perforated conical rotary screw which is mounted in the conical portion for rotation about an axis extending longitudinally of the conical portion; and the stirring means comprises, for the or each rotary screw, a set of perforated rotary blades which are mounted above the screw for rotation abou£ said axis. 3. Apparattus according to claim 2, wherein the sludge inlet comprises an inlet pipe and, for the or each set of rotary blades, a respective vertical tube connected to the inlet pipe and having an exit orifice which is positioned above the set of rotary blades and is provided with a deflector for sludge flowing out of the exit orifice, which deflector is positioned substantially midway between the top of the conical portion and the top of the tank. . Apparatus according to claim 2 or further comprising a level detectors for defecting when flakes compressed tc^ given density fall below a predetermined minimum limit level in the tank and when flakes compressed to a given density rise above a predetermined maximum limit level in the tank, and means for adjusting the rate of discharge of said compact mass through the discharge orifice in response to output conditions of said level detectors. ^ 5. Apparatus according to claim 4, wherein said adjusting means is operative to control the speed of rotation of the or each set of rotary blades and the or each conical rotary screw. 6. Apparatus according to claim or 5, wherein said adjusting means is operative to vary the eross-sectional area of the 43598-2- f discharge orifice. 7. Apparatus according to claim 4, 5 or 6, comprising a which is connected to the discharge compact means, and wherein said adjusting means is operative to control the flow rate of the pump. 8. Apparatus according to any one of claims 2 to 7» wherein the sludge inlet is provided with an inlet for flocculation agents to be added to the sludge. 9. Apparatus according to any one of claims 2 to 8, wherein, for the or each conical rotary screw, the respective set of rotary blades and the screw are arranged to be driven by the same shaft. 10. Apparatus according to any one of claims 2 to 8, wherein, for the or each conical rotary screw, the respective set of rotary blades and the screw are arranged to be driven by respective shafts disposed concentrically one within the other. 11. Apparatus according to any one of claims 2 to 10, wherein the or each set of rotary blades comprises a plurality of superposed rows, each row comprising at least two of the blades. 12. Apparatus according to any one of claims 2 to 11, comprising a horizontal plate which is disposed below and in the vicinity of the discharge orifice for collecting the discharged compact mass thereon, the plate being adjustable in height. 13- A method of compacting fluid sludge, substantially as hereinbefore described with reference to Figure 1, 2 or 3 of the accompanying drawings.

1 . Apparatus for compacting fluid sludge, substantially as hereinbefore described with reference to Figure , 2 or 3 of 43598-2 the accompanying drawings. 15· Sludge which has been compacted by the method of claim 1 or 13.