Travelling sheet, flat-bed filter apparatus and system

Travelling sheet, flat-bed filter apparatus to filter contaminated liquids supplied from a contaminant tank (24) and deliver filtered fluid to a fluid outlet (50) comprising

• a housing (10;
• 12, 20) defining a chamber therein and having a bottom wall (12);
• a perforate divider means (18) located essentially horizontally and subdividing the chamber into an upper contaminant chamber (20') and a lower filtrate chamber (14) therebelow;
• a web of filter medium (28), extending from outside of the housing into the contaminant chamber (20') and therebeyond outside of the housing,
• the perforate divider means having unperforate, marginal portions;
• the housing defining said contaminant chamber including a shallow hood, or cap-shaped element (20) extending over said perforate divider means (28) and having depending edges, said depending edges being positioned to directly engage the web of the filter medium (28) in the region of the marginal unperforate portions of said perforate divider means;
• contaminated liquid inlet means formed in said hood, or cap-shaped element (20) and a connection conduit (26) extending between said contaminant tank (24) and the contaminated liquid inlet means to supply liquid to said upper contaminant chamber (20');
• means engageable with said web of filter medium moving fresh filter medium from a supply (40) into the contaminant chamber, and remove used filter medium therefrom;
• moving means (38) coupled to the hood, or cap-shaped element (20) to selectively move said element in engagement with the filter medium, or lift the depending edges off the filter medium;
• filtrate outlet means (50) connected to said filtrate chamber (14);
• means to effect sealing engagement of said filter medium (28) with the depending edges of said hood, or cap-shaped element (20) and the unperforate marginal portions of the perforate divider means (18), and additionally to move liquid through the filter, comprising
• a combination of a vacuum and a liquid suction pump means (22) connected to the filtrate chamber (14) and forming the sole source of pressure differential to move the contaminated liquid from the contaminant tank (24) through said conduit means and the inlet means into the contaminant chamber (20'), for filtration by the filter medium (28) and pumping to the fluid outlet (50) to provide for direct supply of liquid from said contaminant tank (24) to the contaminant chamber (20') and exposure of said combination pump means (22) to only fluid which is contaminated and simultaneously provide for vacuum within the contaminant chamber (20') which holds the depending edges of the movable hood, or cap-shaped element (20) in sealing contact with said filter medium and against the unperforate portions of said perforate divider means (18);
• control means (C) cyclically, respectively closing and opening said inlet means and starting operation of said pump means to create a vacuum in the contaminant chamber;
• vacuum sensing means (621, 921) connected to said contaminant chamber;
• a controlled valve means (969) in the conduit means (926) to control flow of contaminated liquid therethrough;
• the control means (C) being additionally connected to for control by said vacuum sensing means and processing the information of sensed vacuum to provide control signals to said controlled valve means (969) having controlled parameters controlling the flow condition of contaminated liquid to the filter as a function of the vacuum in the contaminant chamber;
• and wherein, for use as a protected gas or protected atmosphere filter, the portion of the housing defining said filter chamber (814) and forming the bottom wall comprises a bottom plate (812) having marginal unperforate portions;
• the depending edges of the shallow hood or cap-shaped element (820) and having marginal portions engaging said unperforate portions of the bottom plate, with said filter medium interposed;
• duct means (865, 866) formed in said unperforate portions and terminating at the surface facing, the marginal of said hood or cap-shaped element;
• a source (970) of protective gas, said duct means being connected to the source of protective gas to supply protective gas to said contaminant chamber (820') upon vacuum-and-liquid suction operation of said pump means (22), leakage of said gas at the junction of said portions, with said filter medium (828) interposed, introducing said protective gas into said contaminant chamber and preventing ingress of ambient air.