Die for extruding ceramic material to form a body of cellular structure, and a method of obtaining said die

Claim 1

A die for extruding a ceramic material to manufacture a body of cellular structure, said die comprising a succession of elongated thin wall tubular coaxial components fitted one around another, said elongated thin wall tubular coaxial components including integrally radial shoulders at their upstream ends projecting radially outwardly and overlying the upstream ends of the immediately adjacent tubular coaxial components radially outwardly thereof, means forming between successive radially adjacent components, longitudinal ducts, means defining annular ducts communicating with the downstream ends of said longitudinal ducts, the bottoms of said coaxial components being fitted, one around another, and having essentially radial notches level with the annular ducts, and the width of said notches being less than that of the longitudinal ducts, so that the ceramic material which flows through said longitudinal ducts is evenly distributed in the annular ducts and in the radial notches to form a body of cellular structure directly on extrusion, and wherein the coaxial components which are fitted one around another include an inner, central component bearing a radially outwardly projecting shoulder at the upstream end thereof overlying the upstream end of the immediately adjacent elongated thin wall tubular coaxial component with a succession of intermediate components radially fitted successively one around another from said central component up and to an outer radial component and wherein said outer radial component forms a support nozzle, and wherein said radial notches are provided exclusively at the downstream ends of said intermediate components.

Claim 9

A method of manufacturing a die for extruding a ceramic material to produce a body of cellular structure, said die comprising a succession of elongated thin wall coaxial components concentrically fitted one around another, successive radially adjacent components defining between them longitudinal ducts, annular ducts communicating with the downstream ends of said longitudinal ducts, the bottoms of said coaxial components being fitted, one around another, and having essentially radial notches level with the annular ducts, and the width of said notches being less than that of the longitudinal ducts, so that the ceramic material which flows through the longitudinal ducts is evenly distributed in the annular ducts and in the radial notches to form a cellular structure directly on extrusion, said method comprising: forming a radially outwardly directed shoulder on the upstream end of a first, inner tubular component, forming an annular groove at the downstream end of said first, inner tubular component, forming a series of longitudinal grooves at circumferentially spaced positions around the radial outer surface of said first tubular component extending the length thereof and through said radially outwardly directed shoulder, forming a radially outwardly directed shoulder on a second tubular component and fitting said second tubular component concentrically about said first tubular component, subsequently machining said second tubular component to provide an annular groove and longitudinal grooves analogous to those on said first component, and progressing in similar steps regarding said successive radially adjacent components to create said die capable of extruding a body of cellular structure directly from the downstream end of said die, and wherein said radial shoulders fix the positions of said succession of said elongated thin wall tubular coaxial components concentrically about each other while permitting free flow of ceramic material through said longitudinal grooves passing through said shoulders.

Claim 10

A method of manufacturing a die for extruding a ceramic material to produce a body of cellular structure, said die comprising a succession of elongated thin wall coaxial components concentrically fitted one around another, successive radially adjacent components defining between them longitudinal ducts, annular ducts communicating with the downstream ends of said longitudinal ducts, the bottoms of said coaxial components being fitted, one around another, and having essentially radial notches level with the annular ducts, and the width of said notches being less than that of the longitudinal ducts, so that the ceramic material which flows through the longitudinal ducts is evenly distributed in the annular ducts and in the radial notches to form a cellular structure directly on extrusion, said method comprising: forming a radially outwardly directed shoulder on the upstream end of a first, inner tubular component, forming an annular groove at the downstream end of said first, inner tubular component, forming a series of longitudinal grooves at circumferentially spaced positions around the radial outer surface of said first tubular component extending the length thereof and through said radially outwardly directed shoulder, forming a radially outwardly directed shoulder on a second tubular component and fitting said second tubular component concentrically about said first tubular component, subsequently machining said second tubular component to provide an annular groove and longitudinal grooves analogous to those on said first component, and progressing in similar steps regarding said successive radially adjacent components to create said die capable of extruding a body of cellular structure directly from the downstream end of said die, and wherein said radial shoulders fix the positions of said succession of said elongated thin wall tubular coaxial components concentrically about each other while permitting free flow of ceramic material through said longitudinal grooves passing through said shoulders.