Electrically powered catalyst heater for fluid treatment systems

A method of manufacturing a monolithic heater body for a heater assembly, the method comprising:

• forming a plurality of intersecting walls, wherein the plurality of walls have a thickness and extend in an axial direction to form a plurality of cells of the honeycomb structure that extend axially from a first end face to a second end face;
• and
• forming a plurality of openings that extend through the thickness of at least some of the plurality of walls, each of the openings defined by a shape having a downstream side and an upstream side;
• wherein, for each of the plurality of openings:
• (i) a first lateral dimension measured at a downstream axial extreme of the downstream side is wider than a second lateral dimension measured at an upstream axial extreme of the upstream side, or
• (ii) a flow area of an entirety of a downstream axial half of the shape is larger than an entirety of an upstream axial half of the shape, or
• (iii) a maximum lateral dimension of the shape is located in the downstream axial half of the shape, and all lateral dimensions in the upstream axial half are less than the maximum lateral dimension, or
• (iv) a combination thereof, and
• wherein each of the plurality of openings taper to a tip that points into an upstream direction and away from the downstream side and
• wherein the plurality of openings are arranged in a plurality of rows, each row comprising at least two of the plurality of openings arranged laterally, and the plurality of rows being axially spaced along the heater body.

A heater assembly comprising:

• a heater body comprising a monolithic honeycomb structure comprising a plurality of intersecting walls, wherein the plurality of intersecting walls have a thickness and extend in an axial direction to form a plurality of cells of the honeycomb structure that extend axially from a first end face to a second end face;
• a first electrode coupled to the heater body;
• a second electrode coupled to the heater body, wherein a current-carrying path is defined over the plurality of intersecting walls between the first electrode and the second electrode;
• and
• a plurality of openings that extend through the thickness of at least some of the plurality of intersecting walls, each of the openings defined by a shape having a downstream side and an upstream side, the upstream side positioned to encounter the flow of gas before the downstream side;
• wherein, for each of the plurality of openings:
• (i) a first lateral dimension measured at a downstream axial extreme of the downstream side is wider than a second lateral dimension measured at an upstream axial extreme of the upstream side, or
• (ii) a flow area of an entirety of a downstream axial half of the shape is larger than an entirety of an upstream axial half of the shape, or
• (iii) a maximum lateral dimension of the shape is located in the downstream axial half of the shape, and all lateral dimensions in the upstream axial half are less than the maximum lateral dimension, or
• (iv) a combination thereof, and
• wherein, each of the plurality of openings tapers to a tip that points into an upstream direction, points away from the downstream side, and is positioned to point into the flow of gas, and
• wherein a first axial distance between at least a first adjacent pair of axially-spaced openings is not equal to a second axial distance between at least a second adjacent pair of axially-spaced openings.