Patent ID: 8590158

Claim:
A method of making a filter apparatus comprising the steps of: (I) providing a plurality of plates with a central aperture, wherein each plate is provided as a porous substrate comprising a first material composition including mullite; then (II) infiltrating the pores of the substrate with a second material composition including cordierite; then (III) firing the first composition and the second composition to form the porous ceramic plates that each include the central aperture; then (IV) creating a filter stack by axially spacing the porous ceramic plates from one another in an axial direction with a plurality of compliant spacers to define a plurality of axially spaced apart radial flow areas, wherein the central apertures of the plurality of porous ceramic plates are positioned along a central flow path, and the radial flow areas alternate in the axial direction between a first set of radial flow areas that are open to the central flow path, and a second set of radial flow areas that are closed to the central flow path; and then (V) mounting the filter stack within a housing including a first fluid port in fluid communication with the central flow path and a second fluid port in communication with an outer peripheral flow path defined between the filter stack and the housing, wherein the first set of radial flow areas are closed to the outer peripheral flow path and the second set of radial flow areas are open to the outer peripheral flow path.