Porous sheets and tubes

A wide range of metal, plastic and ceramic porous sheets and tubes are available for use in filbation processes. Of particular interest are metal fibre webs such as the Bekipor range manufactured by Bekaert in Belgium which are available in 316L stainless steel, Inconel 601 or Hastelloy X, and metal media produced by sintering bronze, stainless steel, nickel. Monel, Hastelloy, Inconel, titanium, aluminium or tantalum. 

Sintered metal fibre media are made from long fibres of controlled diameters from 2 pm upwards such media retain the high porosity characteristic of beds of fibres, as illusbated in Table 2.18 where some example properties of Bekipor media are listed. The porosity of these fibre sinters is about twice that of powder sinters, giving a much lower resistance to flow the method of manufacture usually also leads to a narrower pore size distribution. 

Absolute filter rating (pm) Permeability x10 2 (m ) Thickness (mm) Weight (g cm ) Typical porosity %) Dirt-holding capacity (mg cm ) 

The properties more typical for media prepared from sintered metal powders are shown in Table 2.19. These are made from powders of graded spherical particles, with sizes typically in the range 0.5-100 pm, which are compressed and sintered in moulds. A range of shapes of media can be produced, which can be subsequently worked in similar way to other metal fabrications. Cylinders, tubes and sheets are commonly used in filtration 

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