| abstract |
The filter is fabricated by treating an elastic, compressible, large-pore polyurethane foam with an adhesive to retain an adsorber, e.g. active carbon. This (expanded fixed bed) filter medium can be inserted into pipes, tubes, etc., of variable geometry without the use of a container/cartridge or a sealing joint. A 20 mm thick polyurethane foam with a porosity of 3-12 pores/cm. and 30 g/l density is treated with a proprietary adhesive, e.g. 'Impranil-HS' (RTM), and dried. Active carbon is added, followed by heating to 160 deg.C for 2 minutes. The active carbon particles have dia. 0.4-0.6 mm. and specific surface area 1100 m<2>/g, and the loading is 195g/l. |