Fluid treatment device having a multiple ceramic honeycomb layered structure

A fluid treatment device comprising:

• at least two ceramic honeycomb layers each comprising a matrix of walls which defines a plurality of parallel, fluid-conducting cells oriented along an axis, said matrix having opposing faces defining inlets and outlets of said cells,
• at least one layer of air space disposed between honeycomb layers along the axis;
• wherein at least one fluid-conducting cell is continuous from one honeycomb layer, across the layer of air space, to a second honeycomb layer.

A fluid treatment device comprising:

• a monolithic ceramic honeycomb structure having an overall axial length between first and second ends, the structure comprising a matrix of walls which defines a plurality of parallel, fluid-conducting cells oriented in an axial direction, wherein a first plurality of continuous walls form uninterrupted cells in a peripheral portion, extending substantially the entire overall axial length and wherein a second plurality of walls form discontinuous cells, wherein the discontinuous cells are open to a common recess within the structure between the first and second ends.

A fluid treatment device comprising:

• at least two ceramic honeycomb layers arranged in a stacked configuration, each layer including a matrix of walls that defines a plurality of parallel, fluid-conducting cells oriented along an axis, each layer having a leading edge face and a trailing end face;
• at least one layer of air space disposed between honeycomb layers along the axis;
• wherein at least one honeycomb layer has a coating of catalytic material at the leading edge face and does not have a coating of catalytic material at the trailing edge face.