Water purifying filter device

摘要

A filter cartridge for treating drinking water to remove a broad range of microorganisms includes a microbiocidal resin layer, a porous activated carbon filter element and a flow controller to assure a minimum effective residence time of water in the filter under varying pressure conditions. The microbiocidal resin preferably comprises a halogenated resin bed which is effective to kill a broad range of bacteria, viruses and protozoan cysts. The five micron carbon filter element removes any particularly resistant cysts which may have survived passage through the resin bed. The filter may also be provided with a scavenger resin downstream of the haogenated resin bed to remove any free halogens from the final effluent. A buffering resin may also be included upstream of the halogenated resin bed to precondition high pH supply water. Compensation for the decreased microbiocidal activity of the halogenated resin with decreasing supply water temperature may be provided by a temperature sensitive flow control valve which increasingly restricts the flow of supply water into the filter with decreasing water temperature.