Belt filter press and belt for same

A filter belt assembly for separating solid material and liquid, said assembly comprising

• a liquid-permeable, endless lower drainage belt,
• a liquid-impermeable, endless upper press belt,
• a frame which supports a plurality of upper pressure rolls, a plurality of upper guide rolls, a plurality of lower pressure rolls, and a plurality of lower guide rolls, said upper belt being movably mounted on said upper pressure rolls and said upper guide rolls and said lower belt being movably mounted on said lower pressure rolls and said lower guide rolls, said upper and lower pressure rolls being respectively mounted on said frame to form nip-defining pairs through which said upper and lower belts pass, a first pair of pressure rolls through which said belts pass defining an upstream end of a filtering run, an ultimate pair of pressure rolls defining a downstream end of said filtering run, and a second pair of pressure rolls being mounted on said frame relative to said first pair of pressure rolls so that said belts will move upwardly from said first pair to said second pair, each pair of pressure rolls being shaped such that at least side edges of said upper and lower belts are pressed together and gaps are provided between center portions thereof, said gaps between the center portions of said belts decreasing between sequential pairs of pressure rolls in the donwstream direction, one of said plurality of upper guide rolls and one of said plurality of lower guide rolls being mounted on said frame so as to respectively cause said upper and lower belts to converge downwardly towards said first pair of pressure rolls, thereby providing a lead-in run of said belts;
• and a second of said lower guide rolls being mounted on said frame to provide a discharge end of said lower belt, and
• drive means driving the upper and lower belts so as to circulate between said pressure rolls in the direction of said downstream end of said filtering run,
• mixtures of solid material and liquid supplied to said lead-in run of said belts being retained between said belts and subjected to increasing pressure as said belts pass between sequential pairs of pressure rolls along said filtering run, liquid being drained through said lower belt and solid material being retained on the upper belt and returned to said lead-in run and through said filtering run until sufficiently dry be retained on said lower belt and discharged at said discharge end of said lower belt.