Abstract: Embodiments of a key system for filters and their connecting heads, brackets, or other holders are shown. The filter cartridge and its holder each have a keyed surface, one being a protruding “key” and one being a recessed “lock”. Cooperation of these keyed surfaces is required in order for the filter cartridge to be installed in the holder, so that mis-matched cartridges cannot be installed into the holder, for example, to prevent a particular type of cartridge from being placed in a filtration or other process where it would be inappropriate, or undesired. The keyed surfaces are selectively locate-able preferably at different circumferential locations on a perimeter of the filter and a corresponding location on a perimeter of the head/holder. The perimeter may be, for example, on an outer shoulder surface of a filter and an inner surface of a valve head, or on outer and inner surfaces of connectors that provide a liquid seal between the filter and the head/holder.

Abstract: Granules comprise binder-agglomerated active particles for liquid treatment or filtration. Each granule has a center core of a material that itself has binding properties without the addition of other binders or sprays or adhesives, or, alternatively, each granule comprises a matrix of active materials stuck together with the binder. The binder structure preferably ranges from a non-uniform matrix of binder formed by heat-deformed binder particles, to a clump of binder particles generally retaining the original shape or the binder particles, to non-continuous connectors of binder between active particles. The invented two-part media has high surface area per volume of media, which, because the outer surface and inner void surfaces of the particles are preferably substantially covered with active particles, translates to high activity for the preferred treatment process.

Abstract: Granules comprise binder-agglomerated active particles for liquid treatment or filtration. Each granule has a center core of a material that itself has binding properties without the addition of other binders or sprays or adhesives, or, alternatively, each granule comprises a matrix of active materials stuck together with the binder. The binder structure preferably ranges from a non-uniform matrix of binder formed by heat-deformed binder particles, to a clump of binder particles generally retaining the original shape or the binder particles, to non-continuous connectors of binder between active particles. The invented two-part media has high surface area per volume of media, which, because the outer surface and inner void surfaces of the particles are preferably substantially covered with active particles, translates to high activity for the preferred treatment process.

Abstract: Embodiments of a fluid filtering assembly are shown and described, each embodiment including a valve head that routes fluid to and from a filter cartridge and that includes a valve system that automatically opens and closes when the filter cartridge is inserted and removed, respectively. The valve system preferably includes a generally-cylindrical piston with a hollow interior space, which receives a stem member. The stem member has a bottom-end seat or sealing member and has a central body shape that allows fluid to flow up through the piston interior space, either through or up around the stem member. Upon removal of the filter cartridge, the piston is biased to move down into an "off" position, to close both the inlet and outlet fluid passages. In this "off" position, the piston exterior surface blocks off radial fluid inlets and the piston interior surface seals with the stem bottom end seat to prevent fluid backflow out of the piston interior space.