Patent ID: 6939466

Claim:
A fluid filter unit comprising: an upper composite filter medium element; a lower composite filter medium element; a non-filtering separator element, operatively positioned between the upper composite filter medium element and the lower composite filter medium element; and structure operatively connecting the at least two filtration medium elements together, the structure being formed from a material having a tensile modulus of elasticity of about 600 psi to about 35,000 psi at about 73° F. and of about 300 psi to about 10,000 psi at about 212° F., wherein the upper and lower composite filter medium elements comprise: at least two zones of filter material, at least one zone of the filter material comprising a fibrous material and filter aids, each of the at least two zones having a different PRG and being positioned such that at least one zone of each filter medium is disposed proximal to the separator element and at least one other zone of each filter medium is disposed distal to the separator element, the zone of filter medium disposed most proximal to the separator element having an increased relative-PRC to the PRC of the zone of filter medium disposed most distal to the separator element.