A separator element comprising a porous rigid single-piece substrate (2) presenting firstly, at its periphery, a perimeter wall (2.sub.1) that is continuous between an inlet (4) for the fluid medium for treatment at one end of the porous substrate and an outlet (5) for the retentate at the other end of the porous substrate, and secondly, internally, a surface covered by a separator layer (6) and defining an open structure made up of empty spaces (3) for passing a flow of the fluid medium for treatment. The empty spaces (3) are arranged in the porous substrate so as to create within the porous substrate a first flow network (R1) for the fluid medium for treatment, having at least two interconnected flow circuits (R1.sub.1, R1.sub.2) for the fluid medium between the inlet (4) and the outlet (5) of the porous substrate.

A particle filter for an exhaust system, in particular of a motor vehicle, provided with a housing having an exhaust gas inlet and an exhaust gas outlet and a porous filter body being disposed in the housing, the filter body is provided with a cover surface and has a large number of flow channels running parallel in the direction of flow. Accordingly, in the filter body, a sensor well is formed to accommodate a sensor element, where such sensor well penetrates at least one of the flow channels. The disclosure further also concerns a procedure for the manufacture of a particle filter.

A honeycomb structure including a honeycomb structure body, first plugging portions, and second plugging portions. The honeycomb structure body has a porous partition wall. The first plugging portions are disposed at an outflow side end face of inlet cells and an inflow side end face of outlet cells. The inlet cells are the predetermined cells of the honeycomb structure body. The outlet cells are the residual cells of the honeycomb structure body. The second plugging portions are not fired. The first plugging portions form a checkered pattern at the inflow side end face and the outflow side end face. The number of the second plugging portions is within 3% of the number of cell open ends where the first plugging portions are not formed, on both end faces of the honeycomb structure body.

A honeycomb structure having a hexagonal cross-sectional shape of cells and having specific open cells in which open changing portions are present only in a range of 30 mm or less from the first end face, and the open changing portion satisfies relations of 1|(1(D1/D2))100|70 and 1|(1(D3/D2))100|70. D1 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the open end of the cell in the first end face. D2 indicates a diameter of the inscribed circle which comes in contact with the peripheral edge of the open end of the cell in the second end face. D3 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the cell in a cross section perpendicular to a direction from the first end face toward the second end face.

A honeycomb structure having a quadrangular or triangular cross-sectional shape of cells and having specific open cells in which open changing portions are present only in a range of 20 mm or less from the first end face, and the open changing portion satisfies relations of 1|(1(D1/D2))100|80 and 1|(1(D3/D2))100|80. D1 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the open end of the cell in the first end face. D2 indicates a diameter of the inscribed circle which comes in contact with the peripheral edge of the open end of the cell in the second end face. D3 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the cell in a cross section perpendicular to a direction from the first end face toward the second end face.

A catalyzed particulate filter that includes: at least one inlet channel having one end into which a fluid flows and the other end which is plugged, and extending in a longitudinal direction; at least one outlet channel having one end which is plugged and the other end into which the fluid flows, and extending in the longitudinal direction; at least porous wall defining a boundary between the inlet channel and the outlet channel which are neighboring to each other and extending in the longitudinal direction; and a support coated with a catalyst thereon.

In the plugged honeycomb structure, 30% or more of first intersection portions in which a first partition wall intersects a second partition wall are first specific intersection portions in which a diameter of a maximum inscribed circle drawn in the first intersection portion is a specific size for a shortest distance between an inflow cell and an outflow cell, and 30% or more of non-first intersection portions other than the first intersection portions are non-first specific intersection portions in which a diameter of a maximum inscribed circle drawn in a non-first intersection portion is a specific size for a shortest distance between the inflow cells or the outflow cells.