GB693568A - Filter - Google Patents

Abstract

693,568. Filters; filtering media. FILTROX-WERK AKT.-GES. March 15, 1950 [March 15, 1949], No. 6535/50. Class 46 [Also in Group XXVIII] The elements between adjoining frames of a pressure filter each consist of a mechanically resistant porous carrier plate together with a porous filtering layer readily replaceable after saturation supported in front of it; the carrier plate has a useful life appreciably greater (e.g., sixty times greater) than that of the replaceable layer. In a filter press comprising inlet and outlet frames 1 arranged alternately, and having carrier plates 3 between them, the plates 3 may consist of fibres such as wool, cotton, rayon, nylon or glass or mixtures of these, and may be formed before or after treatment with binding agents by weaving, plaiting, felting, pressing or similar processes. The material is rigidified by a binding agent which does not impair the porosity of the basic material and is insoluble in the liquids to be filtered, examples of such binding agents being synthetic plastic materials, cellulose acetate, artificial resins and water glass. The plates resist high liquid pressures even in wet condition and do not shrink. The plates 3 are coated with a slurry 4 of a kieselguhr, sand, pulverized charcoal or other suitable filter aid by passing the slurry in the direction indicated. Upon saturation of the layers 4 with filtration residues, the plates 3 are removed from the press and the layer 4 flushed or scraped off. In a modification each carrier plate is covered with a co-extensive coherent plate in place of the slurry layer and made from materials appropriate to the slurry to be-filtered, such as from textiles, paper and the like. In each case the porosity of the layer supported by the carrier plate is preferably smaller than that of the carrier plate. The carrier plate itself however may possess sufficiently minute pores to be efficient alone; its resistance is preferably such that the liquid must be supplied under pressure, so that the slurry becomes uniformly distributed over its surface. The binding agent of the carrier plate may prevent the growth of fungi and bacteria.