A fluid filter centerpost assembly in combination with a fluid filter cartridge
for creating a "no filter-no run" design according to one embodiment of the present
invention comprises an oval-shaped design for the centerpost assembly and an oval-shaped
design for a seal that is positioned between the centerpost assembly and the fluid
filter cartridge. The centerpost assembly includes a main body having an oval shape
in lateral cross section in unitary construction with a radial flange and interior
shelf. The interior shelf defines a flow opening and a movable valve ball is positioned
on the interior shelf and is able to move in the direction of the flow opening
due to incoming fluid pressure. The fluid filter cartridge includes a closed endcap
with a blocking pin such that when the fluid filter cartridge is installed, the
blocking pin is positioned to prevent the valve ball from closing off the flow opening.
