Automatic filter press

A filter press comprising:

• a substantially cylindrical vessel having an upright axis and having at least one inlet and at least one outlet;
• a plurality of filter elements disposed in said vessel being formed as cylindrical, double-walled tubes, having a perforate surface structure and defining each an annular filtrate chamber communicating with at least one filtrate outlet, said filter elements having upper and lower ends and having different diameters and being disposed concentrically about said vessel axis, one within the other leaving annular spaces between each two of said filter elements, and being supported within said vessel by foot portions formed at their lower ends on a carrier grid extending within said vessel transversely to the axis thereof, the filtrate outlets extending through said foot portions and through said carrier grid, each portion of said carrier grid adjacent a respective said annular space having a filter cake outlet opening extending there-through, said filter elements having head portions at their upper ends;
• a first hollow rotor shaft defining a channel for the supply and discharge of a pressurized fluid and rotatably mounted in said vessel and extending in the vessel axis and being connected to a drive source, said rotor shaft carrying a mounting structure fixedly attached thereto and extending therefrom transversely to the vessel axis and opposite the head portions of said filter elements;
• tubular press elements of different diameters and having upper and lower ends being affixed by foot portions at their upper ends to said mounting structure concentrically with respect to said vessel axis and extending each one in one of said annular spaces defined between said filter elements so as to leave annular spaces on both sides of a press element between same and the opposite filter elements, the press elements being provided at their lower ends with head portions close to the foot portions of said filter elements, said press elements being composed each of a rigid tubular carrier body and two elastically expansible press diaphragms covering both sides of said carrier body and secured thereto at foot and head portions thereof, said diaphragms enclosing a sealed hollow space communicated by a conduit to said channel in said first hollow rotor shaft for the supply and discharge of a pressurized fluid supplied by a pressurized fluid source connected to said channel within said rotor shaft into said hollow space to inflate same and thereby move the diaphragms radially towards the respective adjacent filter elements and to withdraw said fluid from said hollow space to deflate same, respectively;
• and,
• wherein means are provided for reducing and increasing the distance between said head portions of the press elements and said foot portions of the filter elements by relative axial movement with respect to each other of at least said head portions of the press elements and the filter elements between an advanced position in which said head portions of the press elements are in contact with said foot portions of the filter elements, to cover said filter cake outlet openings, and a retracted position in which a distance exists between said head portion of the press elements and said foot portions of the filter elements, to uncover said filter element cake outlet openings.