Sludge hydroextractor

Abstract

A process and apparatus for continuous removal of liquids from sludges. The apparatus includes an endless driven lower pervious belt and an endless driven upper impervious belt. The impervious belt is supported by an upper frame positioned above a fixed lower frame member by spring-loaded, adjustable hydraulic cylinders. The two belts are driven at different speeds to provide continuous shear on sludge pressed between the belts. Each belt is supported on a plurality of horizontally spaced rollers with the rollers for the upper belt and the rollers for the lower belt being longitudinally offset from each other. The horizontal roller spacing from the point of contact of the upper belt to the sludge as it is fed in between the belts is of a diminishing progression which may be arithmetic, geometric, or a combination thereof from the point of contact of the upper belt on the sludge to the discharge end. The adjustable hydraulic spring-loaded supporting arrangement for the upper frame and the diminishing spacing of the rollers provides for easily adjustable and increasing pressure on the sludge substantially irrespective of the thickness of the sludge as it is processed through the apparatus. In the process, the sludge is pumped into a mixing chamber where it is pretreated and conditioned such that a preliminary extraction of liquid can occur as is known in the art. From the mixing chamber, the sludge flows to a preconditioner and then is deposited on the pervious belt for translation through a gravity dewatering zone. The partially dewatered sludge is carried by the pervious belt through a compression zone formed between a pair of belts which apply thereto a continuously increasing extractive pressure for pressing additional liquid out of the sludge material.

Dependencies are inferred from the claim text.