Patent ID: 7534349

Claim:
A hand held dual-stage filtration cartridge comprising: a cartridge including a housing having a first sterilization stage including first semi-permeable filtering elements and a second sterilization stage including second semi-permeable filtering elements, the housing having a first end and a second end with the first end including a fluid inlet port and a fluid outlet port and a member that divides the housing into the first sterilization stage and the second sterilization stage, the fluid inlet port being in fluid communication only with the first sterilization stage, while the fluid outlet port is in fluid communication only with the second sterilization stage, wherein the first and second semi-permeable filtering elements are sealed at the second end of the housing so as to cause the fluid entering the fluid inlet port to flow within lumen sections of the first semi-permeable filtering elements and then be filtered by being conducted across the first semi-permeable filtering elements and then subsequently being filtered again by being conducted across the second semi-permeable filtering elements and into the lumen sections of the second semi-permeable filtering elements prior to being discharged through the fluid outlet port; and a pump mechanism for pumping fluid into first sterilization stage and through both the first and second stages so that twice filtered fluid is discharged through the fluid outlet port, wherein the pump mechanism comprises a piston pump that is operable to draw fluid from a source into a holding chamber associated with the piston pump before being discharged into the first sterilization stage, and wherein the pump mechanism is incorporated in the housing.