CERAMIC HONEYCOMB FILTER

WIPO Patent Application WO/2021/024902

A1

This ceramic honeycomb filter which is provided with a plurality of flow passages partitioned by porous partition walls, and in which a fluid introduced from one end is discharged from the other end, wherein: the plurality of flow passages comprise inflow flow passages each having one open end and the other being a closed end, and outflow flow passages each having one closed end and the other being an open end; and in the cross-section perpendicular to the longitudinal direction of the flow passages, (a) the cross-sectional area of the inflow passages is greater than the cross-sectional area of the outflow passages, (b) the cross-section of each of the inflow and outflow passages is an octagons that is formed by cutting four corners of a square and is four-time rotationally symmetrical, (c) the inflow and outflow passages are arranged alternately in a first direction and a second direction perpendicular to the first direction and disposed so that facing sides are parallel to each other, (d) the opening ratio of the inflow passage is 45-60%, (e) the number of the flow passages is 30-60 pieces/cm2, (f) the thickness t1 of the partition wall between the inflow passages and the adjacent outflow passages is 0.150-0.260 mm, and (g) the thickness t2 of the partition wall between the inflow passages and the adjacent inflow passages satisfies 1.175