GB478758A - Improvements in and relating to filtering apparatus for coal washery slurry - Google Patents

Abstract

478,758. Purifying liquids. GREAVES, H. J. Oct. 24, 1936, No. 28939. [Class 46] In separating liquid and solid products from coal washery slurry liquor, raw or flocculated liquor is delivered to settling compartments S<2> and at least one solid product of separation is mechanically transferred to a basin J where it is removed by an external drum filter D and the apparatus is arranged to have one common liquid level. The liquor may also be flocculated, frothed or mixed in the compartments S<2> and part of the solids may be removed directly therefrom to a point without. Overflows W for partially clarified liquid are provided so as to maintain the common liquid level. As shown, liquor is delivered through a pipe or trough P<1> to a chamber F which may be a flocculating or mixing chamber or may assist in distributing it to the settling chamber S<2>. The settled solids are transferred by a conveyer H to the basin J and drum filter D. The conveyer may be shielded by baffles H<1>. Two compartments S<2> may be arranged sideby-side or at the sides of the drum. In the latter case, solids are transferred to the drum by rotary wheel scrapers or by an air pump connected to a valved chamber between the compartments. Filters may be arranged in one compartment for removing clarified water ; such filters may be of woven-hair cloth as described in Specification 446,445. The outflow from such filters may be controlled by a valve operated from a float whereby the liquid level is maintained. In another form, the liquor is delivered directly to the filter drum basin and overflows into a settling tank from which solids are returned to the basin. In another form, the liquor is divided into two grades, one, a froth containing lighter particles being conveyed to a drum filter, and-the other, a solid slurry, being conveyed to a second drum filter or removed by an elevator. Specification 478,764 also is referred to.