Filter including a porous discriminating layer on a fused single crystal acicular ceramic support, and method for making the same

A filter useful for separating at least one contaminant from a fluid passed through said filter, comprising:

• a support including a porous honeycomb extrusion composed of a non-stoichiometric acicular mullite having properties sufficient to provide high mechanical strength, high impact strength, heat resistance and good resistance to thermal cycling, having a plurality of parallel channels and including a fluid inlet end and a fluid outlet end;
• a plurality of plugs disposed in single alternating ends of said parallel channels, said plugs also being made of non-stoichiometric acicular mullite and interlocked with said honeycomb extrusion;
• and end caps positioned over said fluid inlet and fluid outlet ends, said end caps also being made of non-stoichiometric acicular mullite and interlocked with said honeycomb extrusion;
• said extrusion, said plugs and one of said end caps including surfaces defining an inlet chamber in said filter;
• an external fluid-impermeable glaze covering said support;
• and
• a sintered porous alpha-alumina membrane on said inlet chamber-defining surfaces of said support, said membrane acting as a discriminating layer for filtering and separating.

A method of forming a filter useful for separating at least one contaminant from a fluid passed through said filter, comprising:

• forming a green support composed of a ceramic material capable of being converted in situ into fused, interlocked, single crystal, acicular ceramic particles;
• converting said ceramic material in situ into fused, interlocked, single crystal, acicular ceramic particles, thereby forming a rigid and porous ceramic support having high mechanical strength, high impact strength, heat resistance and good resistance to thermal cycling;
• and
• applying a porous discriminating layer on at least part of said support.

A method of forming a filter useful for separating at least one contaminant from a fluid passed through said filter, said filter including a porous ceramic support, and said method comprising:

• abutting at least two support pieces together, said pieces each being composed of a ceramic material capable of being converted in situ into fused, interlocked, single crystal, acicular particles having properties sufficient to provide high mechanical strength, high impact strength, heat resistance and good resistance to thermal cycling;
• and
• converting said ceramic material in situ into fused, interlocked, single crystal, acicular particles;
• whereby said two support pieces become unified and interlocked by said acicular particles.