Honeycomb filter and method of making it

In a method of fabricating a filter of honeycomb structure for removing solid particulates from fluids passed through the filter comprising the steps of (a) providing a matrix of thin brittle interconnected porous walls defining an inlet end face and outlet end face on opposite sides of the filter and a multiplicity of cells extending between the inlet and outlet faces and through the filter and further having interconnected open porosity of a size and volume sufficient to enable fluid to flow completely across the thickness of the thin walls and to restrict at least a significant portion of the solid particulates from flowing either completely across or through the thin walls in any direction, (b) forming an inlet group of cells open at the inlet end face and closed at the outlet end face and an outlet group of cells open at the outlet end face and closed near the inlet end face, a first subset of the thin walls being shared in common by adjoining inlet and outlet cells and a second subset of the thin walls being shared in common by pairs of adjoining inlet cells, the improvement comprising the step of intersecting in a substantially perpendicular fashion each of the thin walls of the first subset with a thin wall of the second subset whereby a flexing joint is formed therebetween.

In a method of fabricating a filter of honeycomb structure of filtering solid particulates from fluids passed through the filter comprising the steps of (a) providing a matrix of thin interconnected porous walls defining inlet and outlet end faces of the filter and a multiplicity of cells each extending from at least one of the inlet and outlet end faces through the filter and having interconnected open porosity of a size and volume sufficient to enable fluid to flow completely across and through the thin walls in any direction and to restrict at least a significant portion of the solid particulates from flowing either complete across or through the thin walls in any direction, and (b) forming an outlet group of cells open only at one or more of the outlet end faces and an inlet group of cells open only at one or more of the inlet end faces, and adjoining one another and the outlet cells, pairs of adjoining inlet cells sharing a first subset of the thin walls in common and adjoining inlet and outlet cells sharing a second subset of the thin walls in common, the improvement comprising forming the first subset of thin walls with a first substantially uniform thickness and the second subset of thin walls with a second substantially uniform thickness different from the first substantially uniform thickness.