Patent ID: 8197680

Claim:
A multi-step press apparatus for automatic, PLC controlled, sludge dewatering and waste water filtration, comprising: a substantially cylindrical tank for receiving a mixture of sludge or waste water and coagulant, said cylindrical tank being designed to effectively allow suspended solids to be separated and later dewatered, and being provided with a lower, openable port for discharge of dewatered solids and having a substantially vertical cylindrical double layer mesh wired screen including a fine screen layer for discharge of cleared liquid; a centralized inflatable membrane, positioned to press said solids against said screen, whereby a stream of discharged, cleared liquid, passes through the screen and is discharged to a sewage drain or a further tank, said screen being provided with perforations sized to enable the passage of clear liquid therethrough while retaining fine and coagulated solids on the internal surface thereof; a load sensor in contact with the cylindrical tank to determine the combined weight of the apparatus and of solid and liquid internally retained thereon and to control a sequence of operation, and a filling and pressing duration as a function of said weight, whereby a solids cake of about 30 mm thickness of fine and coagulated solids is formed and retained on the internal surface of the fine screen layer, thereby improving the filtering and dewatering capacity of the apparatus, said apparatus further comprising: a bottom opening with a second pneumatic inflatable membrane to seal and to open said bottom opening and thereby enabling downward discharge of solids into a sludge collecting bin; a nozzle assembly including a set of high pressure nozzles located on the external side of the double layer mesh wire screen, to efficiently wash the screen from outside to inside, said nozzles being operationally linked to a drive mechanism which moves said nozzle assembly up and down in response to a PLC command during a cleaning cycle; and a PLC provided to manage all cycles of operation along with pneumatic and electrical control items including activating solenoid valves, pumps and load cells, to provide for a continuous dewatering and filtration operation.