FILTER USED IN THE PROVISION OF SUBSTANTIALLY GERM-FREE WATER

A water filter has a housing with an inlet (12) and an outlet (13) separated by a barrier (17) which is bridged by numerous porous U-shaped hollow fibres (16). The hollow fibre outer surface is exposed to incoming water which migrates through pores to the hollow core to emerge on the other side of the barrier (17). An independent claim is also included for a commensurate process in which impurities e.g. legionnaire bacteria remain trapped on the filter inlet side. The filter is fabricated as a cartridge with a long-life biocide lining and forms part of a hot water bathroom shower. The filter housing holds pref. 50-500 ml of water, and has a throughput of pref. 500-3000 l/hr. The flexible fibre pore size is pref. 0.05 - 0.2 m. The fibre inner diameter is pref. 50-150 m. Each fibre is pref. 30-100 cm in length with total fibre external surface area of pref. 0.05-1.5 m. The fibres are made of pref. polyvinyl fluoride and/or polyether-sulphon. The cartridge holds pref. 30-60 hollow fibres within an elongated housing. The filter cartridge is preceded by a coarse pre-filter.