An exhaust gas purification filter has a honeycomb structure body and upstream side plug members. Cell holes are composed of inlet cell holes and outlet cell holes. In a central area and an outer peripheral area, a gas flow channel cross sectional area Sc1 of the outlet cell holes is larger than a gas flow channel cross sectional area So1 of the inlet cell holes, where Sc1<So1. A first ratio Rc is smaller than a second ratio Ro. The first ratio Rc is a ratio of Sc1 and Sc2. The second ratio Ro is a ratio of So1 to So2. In a first direction X and a second direction Y, the inlet cell holes and the outlet cell holes are alternately arranged, and the cell walls in the central area are larger in thickness than the cell walls in the outer peripheral area.

A honeycomb body having intersecting porous walls which includes first through fourth cells, wherein the cells extend from inlet to outlet face and are plugged to define a repeating structural unit with three inlets and one outlet channel. Repeating structural unit includes a first channel including length L.sub.1, width W.sub.2, and area A.sub.1, a second channel including length L.sub.2, the width W.sub.2, and area A.sub.2, a third channel including the length L.sub.1, width W.sub.1, and area A.sub.3, and a fourth channel including the length L.sub.2, the width W.sub.1, and A.sub.4, wherein the first through third channels are inlets and the fourth channel is a rectangular outlet and at least one of W.sub.1>W.sub.2 and L.sub.1L.sub.2, i.e. W.sub.1>W.sub.2, or L.sub.1L.sub.2, or W.sub.1>W.sub.2 and L.sub.1L.sub.2. Repeating structural unit has a quadrilateral outer perimeter. Particulate filters including the honeycomb body, honeycomb extrusion dies, and methods of manufacturing the honeycomb body are provided.

A honeycomb structure, including: a honeycomb structure body having a porous partition walls which are disposed to define a plurality of cells and a circumferential wall, wherein the partition walls are provided with protrusions which protrude to extend into the cells and are continuously disposed in an extending direction of the cells, the cells have a polygonal shape in a cross section orthogonal to the extending direction of the cells, the plurality of cells include a plurality of specific cells having at least one place where two sides each of which is provided with a different number of protrusions intersect each other, and in the cross section orthogonal to the extending direction of the cells, disposition directions of the shapes of the cells including the protrusions in the specific cells are different in one specific cell and other specific cells other than the one specific cell.

Debris filters fit in fuel assembly lower tie plates and filter fluids passing therethrough. Filters use a series of adjacent plates with aligned peaks and valleys to create several channels. The plates have small excisions in diamond, triangle, or other debris-catching shapes, such as near a lower portion of the filter where fluid enters the filter. Excisions may alternate around each channel, such as four alternating cut-outs in 90-degree intervals about a channel circumference. Excisions may be sized to entrap smaller debris common in reactor coolant flow and liable for fretting damage to fuel cladding. Multiple vertical stages can be used in filters, with different channels for each stage. Ligaments may hold each stage to the next, potentially with a gap between stages for intermixing. Plates, peaks, valleys, ligaments, and excisions may all be formed in a single stamping operation to eliminate excess or overlapping pieces or extensions.

A honeycomb filter includes a pillar-shaped honeycomb substrate and a plugging portion provided at an end portion on either an inflow or outflow end face side of cells, wherein, in a section orthogonal to the cell extending direction, the shapes of an inflow cell having the plugging portion and an outflow cell having the plugging portion are hexagonal. In the plurality of cells, a plurality of inflow cells surround one outflow cell such that one side of the inflow cell and one side of the outflow cell adjacent to the inflow cell are parallel. The partition wall includes a first partition wall and a second partition wall, at least one of the first partition walls is configured such that a ratio of a thickness of the second partition wall to the first partition wall is 1.0 to 2.5, and a total open frontal area is 35% to 95%.

A honeycomb body (300) including a plurality of radially-extending walls (322) intersecting with a plurality of circumferentially-extending walls (324), the plurality of radially-extending walls (322) and the plurality of circumferentially-extending walls (324) form a plurality of circumferential zones (334A, 334B, 334C) of cells (308). The plurality of circumferential zones (334A, 334B, 334C) of cells (308) includes a first zone of cells (334A) including two or more first rings of cells (330) and having a first cell density, and a second zone of cells (334B) including two or more rings of cells (330) having varying cell densities across the two or more rings of cells. Other structures and extrusion dies are disclosed.

A honeycomb structural body includes: a porous cell wall that partitions a cylindrical casing; and a large number of cells extending in the axial direction X thereof and alternately blocked at an upstream end face. The large number of cells include plugged cells having plugs and penetrating cells that do not have the plugs. The plugged cells and the penetrating cells both include complete cells and incomplete cells. At least some of plugged incomplete cells of the incomplete cells have a cross-sectional area smaller than a cross-sectional area of penetrating complete cells, and are configured as blocked cells that are entirely blocked inside in the axial direction.

Provided is a honeycomb filter, including: a pillar-shaped honeycomb substrate having an inflow end face and an outflow end face and including a porous partition wall surrounding a plurality of cells; and a plugging portion disposed at any one of ends of the cells at the inflow end face and at the outflow end face. In a cross section orthogonal to an extending direction of the cells, inflow cells have a pentagonal or a hexagonal shape, and outflow cells have a square shape. The cells are configured that the inflow cells surround one outflow cell and one side of an inflow cell and one side of an adjacent outflow cell are parallel to each other. The partition wall is configured that thickness of a first partition wall disposed between the inflow cells and the outflow cells is smaller than thickness of a second partition wall disposed between the inflow cells.

A thermal shock resistant and asymmetric honeycomb ceramic wall-flow filter, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface. Inlet channels (1) and outlet channels (2) are provided on both the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface. The inlet channels (1) are in communication with the outlet channels (2). Outlet ends of the inlet channels (1) and inlet ends of the outlet channels (2) are sealed. An inner diameter of the inlet channel (1) is greater than that of the outlet channel (2). A cross-section of the inlet channel (1) is a square, and is provided with a fillet, or two adjacent edges are connected by two connecting lines, or two adjacent edges are connected by two connecting lines or a circular arc located between the two connecting lines. A cross-section of the outlet channel (2) is a square, and is also provided with a fillet or a chamfer. The filter has good mechanical properties, low back pressure, and excellent thermal shock resistance.

Provided is a porous honeycomb filter comprising a porous first cell wall that permits exhaust gas to permeate, a second cell wall that permits exhaust gas to permeate than the first cell wall, and a cell that is surrounded by the first cell wall and the second cell wall to form an extending gas flow passage. The second cell wall has a smaller porosity than the first cell wall.