Filter medium for an oil filter

An oil filter, comprising:

• a first filtration layer of coarse filter media;
• a second filtration layer of fine filter media;
• and
• a grid spacer comprising a first side, a second side, and a plurality of struts, the plurality of struts defining a plurality of discrete intermediate chambers that extend from the first side of the grid spacer to the second side of the grid spacer;
• wherein:
• said first and second filtration layers are each discrete from said grid spacer;
• the second filtration layer's fine filter media has a beta value of beta 35 greater than 1000;
• the first filtration layer's coarse filter media is relatively open, as compared to the second filtration layer's fine filter media;
• each of the plurality of discrete intermediate chambers comprises a first open end proximate the first side of the grid spacer and second open end proximate the second side of the grid spacer;
• the first and second filtration layers are disposed on and coupled to the first and second sides of the grid spacer, respectively, such that:
• the first open end of each of the plurality of discrete intermediate chambers is covered by said second filtration layer;
• the second open end of each of the plurality of discrete intermediate chambers is covered by the first filtration layer;
• and
• said first and second filtration layers are spaced apart from one another in a direction of fluid flow in an oil circuit;
• the second filtration layer's fine filter media further comprises a plurality of through-holes formed therethrough, wherein each of said plurality of through-holes extends through the second filtration layer's fine filter media is substantially aligned with a center of the second open end of a corresponding one of said plurality of discrete intermediate chambers;
• the first and second filtration layers are each configured to filter an oil flow;
• and
• each of the plurality of through-holes is configured to allow at least a portion of an oil flow to bypass the second filtration layer's fine filter media without being filtered by the second filtration layer's fine filter media.

A method of filtering oil in an oil circuit, the method comprising:

• providing a filter medium in an oil circuit wherein the filter medium comprises:
• a first filtration layer;
• a second filtration layer;
• and
• a grid spacer comprising a first side, a second side and a plurality of struts, the plurality of struts defining a plurality of discrete intermediate chambers that extend from the first side of the grid spacer to the second side of the grid spacer;
• and
• causing oil in said oil circuit to flow through said filter medium from the second filtration layer to the first filtration layer, thus filtering the oil;
• wherein:
• the first filtration layer is discrete from the grid spacer;
• the second filtration layer is discrete from the grid spacer;
• the first filtration layer's filter media is relatively open, compared to the second filtration layer's filter media;
• each of the plurality of discrete intermediate chambers comprises a first open end proximate the first side of the grid spacer and a second open end proximate the second side of the grid spacer;
• the first and second filtration layers are disposed on and coupled to the first and second sides of the grid spacer, respectively, such that:
• the first filtration layer covers the first open end of each of the plurality of discrete intermediate chambers;
• the second filtration layer covers the second open end of each of the plurality of discrete intermediate chambers;
• and
• said first and second filtration layers are spaced apart from one another in a direction of fluid flow in said oil circuit;
• said second filtration layer comprises a plurality of through-holes, wherein each of said plurality of through-holes extends through the second filtration layer's filter media and is substantially aligned with the second open end of a corresponding one of said plurality of discrete intermediate chambers;
• the first and second filtration layers are each configured to filter an oil flow;
• and
• each of the plurality of through-holes is configured to allow a portion of an oil flow to bypass the second filtration layer's filter media without being filtered by the second filtration layer's filter media.