Patent ID: 8764984

Claim:
A filter-in-filter fluid filter cartridge comprising: a first filter element; a second filter element radially spaced apart from the first filter element; a centertube positioned between the first filter element and the second filter element, the centertube having a cylindrical side wall and first and second open ends at opposite ends of the cylindrical side wall, the cylindrical side wall including a solid top portion that extends along a length of the second filter element and a bottom portion that includes a plurality of centertube flow passages that is adjacent the second open end and generally below the second filter element, the solid top portion being formed without openings to prevent fluid communication between the first filter element and the second filter element; a funnel passageway attached to an interior surface of the cylindrical side wall of the centertube above the bottom portion, the funnel passageway including a central flow passage and a plurality of perimeter funnel flow passages fluidly isolated from the central flow passage; wherein a first fluid is configured to pass through the first filter element and the centertube flow passages and the second fluid is configured to pass through the second filter element, the central passageway and the perimeter funnel flow passages without contacting the first fluid.