Method for producing a ceramic filter element

Patent metadata

Field	Value
Publication number	US-9333449-B2
Application number	US-201314019156-A
Country	US
Kind code	B2
Filing date	Sep 5, 2013
Priority date	Aug 5, 2008
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

In a method for manufacturing a ceramic filter element for an exhaust gas filter of internal combustion engines, a combustible non-ceramic filter medium is shaped to a coil and impregnated with a ceramic slurry having a powder size distribution selected such that the ceramic filter element in the finished state has a desired porosity distribution that varies across the coil cross-section of the ceramic filter element.

First claim

The invention claimed is:

1. A method for manufacturing a ceramic filter element for an exhaust gas filter of internal combustion engines; the method comprising:
providing a combustible non-ceramic filter medium in an unwound state dividable into zones along its length in the unwound state such that the zones are arranged sequentially along the length;
shaping the combustible, non-ceramic filter medium to a coil; and
impregnating the coil with a ceramic slurry having a powder size distribution that is varied across the different zones of said filter medium such that the ceramic filter element in a finished state has an increasing weight per surface unit from zone to zone along the length providing porosity distribution as a volume percent of pores that varies across a radial coil cross-section of the ceramic filter element from an interior of the coil to an exterior of the coil.

2. The method according to claim 1 , wherein
the porosity distribution of the ceramic filter element in the finished state decreases across the radial coil cross-section from an interior to an exterior of the ceramic filter element.

3. The method according to claim 1 , wherein
the porosity distribution of the ceramic filter element in the finished state increases across the coil cross-section from an interior to an exterior of the ceramic filter element.

4. The method according to claim 1 , wherein
the combustible non-ceramic filter medium is comprised of organic material.

5. The method according to claim 4 , wherein
the organic material is cellulose.

6. The method according to claim 1 , wherein
the combustible non-ceramic filter medium is comprised of synthetic material.

7. The method according to claim 1 , further comprising the step of
drying the coil after impregnating.

8. The method according to claim 7 , further comprising the step of
sintering the coil after drying;
wherein said sintering step includes step of
burning off said non-ceramic filter medium such that said non-ceramic filter medium is removed by combustion and a rigid ceramic filter element remains.

9. The method according to claim 8 , wherein
the step of sintering follows a sintering program determined by a temperature curve over time and an atmosphere in a sintering furnace.

10. The method according to claim 7 , wherein
the step of drying is carried out in a microwave device.

11. The method according to claim 7 , wherein
the step of drying is carried out in a conditioning cabinet.

Assignees

• Mann & Hummel Gmbh

Inventors

• Franz Andreas

Classifications

• C04B38/0083

  from one or more corrugated sheets or sheets bearing protrusions by winding or stacking · CPC title

• C04B38/0615

  the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles (C04B38/0022 takes precedence) · CPC title

• C04B2111/00793

  as filters or diaphragms · CPC title

• B01D2239/0695

  Wound layers · CPC title

• B01D46/527

  in wound arrangement · CPC title