Patent ID: 8231793

Claim:
A filter cartridge for installation in a base assembly with a housing insert therein; the filter cartridge for filtering a stream of liquid; the filter cartridge comprising: (a) a first media pack having a tubular shape defining a first open interior volume; (i) the first media pack having a first end and a second end; (ii) the first media pack oriented to filter a first stream of liquid as the first stream flows through the first media pack and into the first open interior, when the filter cartridge is operably installed in the base assembly; (b) a second media pack of a higher efficiency than the first media pack; the second media pack having a tubular shape defining a second open interior volume; (i) the second media pack having first and second ends; (c) a center endcap between the first media pack and the second media pack; the center endcap having a first side, an opposite second side, and a tubular wall defining a bore extending between the first and second sides; (i) the first media pack second end being secured to the center endcap first side; (ii) the second media pack first end being secured to the center endcap second side; (iii) the tubular wall defining a slot arrangement; the slot arrangement being a flow passage between the bore and a region outside of the center endcap; (iv) the slot arrangement dividing the first stream of liquid from the first media pack as the first stream flows from the first open interior and into the bore of the center endcap; the slot arrangement dividing the first stream so that only a portion of the first stream flows through the slot arrangement to the region outside of the center endcap and through the second media pack; (d) a seal member surrounding the center endcap oriented to form a seal with a housing insert in a base assembly, when the filter cartridge is operably installed in the base assembly; the seal preventing the first stream of liquid from flowing through the second media pack until it has flown through the first media pack.