POROUS MATERIAL FOR FILTERS Russian patent published in 1999 - IPC

FIELD: manufacture of filters. SUBSTANCE: porous material for filters is made of two layers of particles of different sizes. Relation of large and small particles in two bordering layers lies within limits of 1.6-3.4. Average size of particles of fine-grained layer equals size of pores of coarse-grained layer. Thickness of coarse-grained layer is taken within bounds of 1.5- 3.0 of average size of particles making it with porosity of material in layers within limits of 45-55%. Invention makes it feasible to increase fineness of cleaning by 2.5- 4.0 times which leads to prolongation of service life by 2-3 years and to reduce operational expenses by 10-15%. EFFECT: increased fineness of cleaning, prolonged service life of filters and reduced operational expenses. 3 dwg, 1 tbl