Patent GB-422987-A (GB)
Title: Apparatus for filtering and purifying liquids
IPC: B01D29/00
Filed: 1934-01-30
Abstract: 422,987. Filters. LEIGH, A. G., 17, Southport Road, Chorley, Lancashire. Jan. 30, 1934, No. 3081. [Class 46] Apparatus for filtering water, sewage, trade effluents, wood pulp, &c. consists of vertical frames covered with asbestos fabric or other filtering material and separated by frames open at the base to provide communication with a chamber beneath for the reception of solid matter removed therefrom by scraping or cleaning devices applied between the filtering units, the frames being clamped together and connected with the chamber beneath in a water - tight manner. The flanged circular filtering units 1 and intervening spacing frames 3 are clamped together by screwed rods 25 and are bolted or otherwise secured across the chamber 2. Each unit consists of a frame 5 having outlet orifices 6, a central ring 8, and sides of grooved or studded perforated sheet metal or gauze held apart by perforated metal rings 17. Filtering fabric is applied to the frame 5 by folding it round the base and then cutting to shape, the centre part being clamped to the ring 8. A pipe 9 connected to a high-pressure water supply passes through the rings 8 and is provided with nozzles 12 and with arms 13 carrying rubber scrapers. The liquid to be treated is passed under pressure into the chamber 2 through a pipe 10. The chamber 2 may be provided with a valved outlet pipe 22, an inspection opening fitted with a cover 20, and a screw-conveyer 30 for delivering the separated solid material or sludge to an outlet or to a compressor. The latter consists of a screw 30a working in a tapered chamber 26 provided with an adjustable spring-controlled outlet valve 43. Liquid escapes from the compressed material through a gauze or perforated lining 28, filtering fabric or material 27, grooves or passages in the wall of the chamber 26, and an outlet pipe 34. High pressure cleaning water may be forced through in the reversed direction through a pipe 35. When the compressor is dispensed with the screw 30 may deliver the sludge into a container provided with a screwdown discharge valve operated by hand, or into a chamber 56a, Fig. 9, which discharges automatically at intervals. The chamber 56a is provided with a balance weight 46 which normally raises it so that the discharge valve 69a is closed. When a sufficient weight of solid matter has accumulated, the chamber sinks and opens the outlet. The scraper arms 13 may be dispensed with and the filter unit cleansed only by water from the jets 12 The apparatus is provided with air cocks 52, a pressure gauge 55, and discharge troughs 53 for the filtered liquid. When the pressure becomes excessive a motor is started by means of a switch and drives the tubular shaft 9 and the screw conveyer 30 through toothed gearing 60, 61, 62. The switch may be moved automatically by a slotted lever 70 engaging the rod of a spring-controlled piston 63 working in a cylinder communicating with the filtering apparatus through a pipe 65. In a modification the filtering units are of square shape and the filtering fabric may be applied to all of them in one piece by folding it alternately under and over them. The nozzles 12 are carried by a central tubular shaft below the units, and the scraper arms 13 by two side shafts below them, all these shafts being operated manually by levers. The conveyer 30 may be driven by a motor operated by the discharged liquid. Two filtering fabrics may be used together. The apparatus may be mounted on wheels for transport and provided with a motor and pump.