GB488151A - Method and apparatus for purifying liquids - Google Patents

Abstract

488,151. Filters. WALLQUIST, I. Nov. 17, 1937, No. 31597. [Class 46] A method of filtering liquids employing an endless filtering cloth running over two or more liquid-pervious rotary drums each in a container, is characterized in that a layer of particles formed upon the portion of the cloth engaging the drum of the first container is used in the passage of the cloth over the second drum to filter liquid supplied to the container of the second drum. As shown in Fig. 1, two basins 1a, 1b contain, respectively, two pervious drums 2a, 2b over which runs an endless filtering cloth 5. Liquid enters the basin 1a through inlet 8a and passes through the cloth 5 and the surface of the drum 2a to the interior of the drum, from which it flows through pipe 9a to the basin 1b. Coarse particles form on the cloth passing over the drum 2a, and act as a filter to catch finer particles as the liquid passes from the basin 1b through the drum 2b. The cloth passes over a roll 6 after which the layer of particles is removed by means of a scraper 18, or by means of a spray pipe 11. In the arrangement shown in Fig. 7, three drums and three containers are provided, the first drum and container being used in connection with an auxiliary supply of liquid with coarse particles, for use when the liquid to be filtered does not contain sufficient coarse particles to form a satisfactory layer on the filtering cloth 5. The auxiliary supply enters the first container at 8a and is discharged through outlet 3a, or may pass through pipe 9a to the second container. The liquid to be filtered enters the second container through pipe 8b and passes through both the second and third drums. Endless cloths 12a, 12b support the layer 10 of particles on the cloth 5 as it passes between the drums.