Patent ID: 7238285

Claim:
A liquid filter arrangement comprising: (a) a housing; (b) an internally received filter cartridge; and (c) an internally received treatment agent storage and release cartridge; the treatment agent storage and release cartridge having a diffusion aperture arrangement providing for: (i) an initial static flow diffusion operation; and, (ii) a later dynamic flow diffusion operation; (iii) the internally received treatment agent storage and release cartridge being configured only for release of treatment agent into unfiltered liquid within the housing, during use, at a location upstream of the internally received filter cartridge, and the treatment agent storage and release cartridge having an outer side wall, an inner side wall and an end wall between the outer and inner side walls; (A) the end wall having a flow aperture arrangement therethrough; (B) the outer side wall having a flow aperture arrangement therethrough; (C) the inner side wall defining a flow channel and having no diffusion apertures therethrough; and, (D) a total diffusion area of the flow aperture arrangement in the side wall being at least 50% greater than a total diffusion area of the flow aperture arrangement in the end wall, wherein the housing, the internally received filter cartridge and the internally received treatment agent storage and release cartridge are configured to define an inlet flow path, for liquid to be filtered, at a location across an end wall of the treatment agent storage and release cartridge and then across a side wall of the treatment agent storage and release cartridge and the filter cartridge.