GB820130A - Filtering plant - Google Patents

Abstract

820,130. Filters. SULZER FRERES S. A. Dec. 7, 1956 [Dec. 7, 1955], No. 37548/56. Class 46. [Also in Group XXIX] Unfiltered water flows along a main 50, Fig. 3, and past open valves 53, Fig. 4, into overflow channels' 44 and thence past open flap valves 47 and over weirs 46 into filter sections 40 to 43 where it can rise towards the top edges of partition walls 96. It passes down through sand 14, and, as filtered water, through the perforated floor 15, the cushion chamber 26, and through the perforated upper wall into the passage 18 of each section, whence it flows past an open hydraulically-actuated remotecontrolled disc valve 66 (see Group XXIX) into a filtered-water discharge header 64. A flap valve 49 for each section is open during filtration. During washing of any section, valves 53 and 47 (and, at first, valves 49, 57 (see below) and 66) are closed and valve 62 is open. Scavenging air is fed from an air header 58 through a valve 62 (like valve 66) into an air-supply passsage 60 disposed in the cushion chamber 26 and provided with outlet apertures, the water level in chamber 26 being thereby depressed. As soon as an air cushion extending beneath the entire floor 15 has formed in the chamber 26, valve 66 is opened, and filtered water, acting as wash water, is fed into the passage 18. It passes through chamber 26 and, with the air, through floor 15 and sand 14, and the resulting sludge liquor rises towards the top edges of the walls 96. After a time valves 49 and a valve 57 (like valves 68) is opened, the liquor spilling over weir 48 and flowing through the valve 57 into a sludge liquor discharge header 55. Figs. 1 and 2 show plant which is not according to the invention, but which is stated to be known. Raw water supplied to a main 30, 31, Fig. 1, flows through pipes 35 into troughs 12, Figs 2, and over the edges 13 into sections 2 to 9, through sand 14, perforated floor 15, cushion chamber 26 and slotted floor 16. Filtered water from passage 18 passes through pipes 19, 22 into the common header 24 and thence to use. During washing valves 34, 23 are closed and valves 29, 27 and 38 are open. Scavenging air flows from a header 63 through pipes 28 into passages located beneath troughs 12 and into cushion chambers 26 and from there, with the air, through perforated floors 15 and sand 14. The wash water containing dirt spills over edges 13 into troughs 12, Fig. 2, whence it is led through pipes 37 into a sludge liquor discharge header 39.