Patent GB-776967-A (GB)
Title: Permeable body with extendable layers and conically increasing permeability
IPC: B01D39/08
Filed: 1952-05-17
Abstract: A permeable body for filtering, screening and jigging and for sorbing processes generally consists of at least three extendable layers each of which has a different permeability in use, the layers being arranged one above another so that in use each layer is less permeable than the one immediately below it so that the permeability extends conically or increases successively, from one working surface to the other, the layers being held together by means permitting the alteration of their permeability in use.  A filter medium, absorbing body or calendar padding comprises, at the top, a cotton cloth having nine threads per cm., followed by, in order: cotton cloths having, respectively, eight and six threads per cm., a nylon lattice of six meshes per cm., a cotton net having five threads per cm., again a six-mesh nylon lattice and finally a cotton net having four threads per cm.  This may be used as a padding for drying materials spanned over a perforated drum.  A combined unit may be formed from two or three such units with or without one or two stiff sieves with conically-extending apertures.  For drying and filtration a strong cotton net having four meshes per square inch is folded into ten layers which are sewn together, or ten layers are wound upon a perforated drum; below each third layer is a strong plastic lattice of four meshes per inch.  A gas filtering unit consists of three strong cotton fabrics woven together, each half-a-millimetre thick but having, successively, 22, 18 and 15 threads per cm.  For screening or jigging five thin perforated sheets of pliable plastic material or rubber and/or extendable nets of iron or the like with chain links, the numbers of holes per inch increasing from layer to layer throughout, are arranged in a frame upon a support.  A filter aid resting on a porous support in a container to which is introduced the liquid to be filtered comprises one part each of kieselguhr, kieserite, manganous carbonate and barium sulphate in layers in that order, the kieselguhr being uppermost and having the smallest particle size and lowest specific gravity, and the barium sulphate being lowermost and having the largest particle size and highest specific gravity.ALSO:A permeable body for screening, jigging and like processes consists of at least three extendable layers each of which has a different permeability in use, the layers being arranged one above another so that in use each layer is less permeable than the one immediately below it so that the permeability extends conically or increases successively, from one working surface to the other, the layers being held together by means permitting the alteration of their permeability in use.  A combined unit may be formed from two or three such units with or without one or two stiff sieves with conically-extending apertures.  For screening or jigging five thin perforated sheets of pliable plastic material or rubber and/or extendable nets of iron or the like with chain links, the numbers of holes per inch increasing from layer to layer throughout, are arranged in a frame upon a support.