Abstract: The resistance of a honeycombed structure to damage from asymmetric thermal shock occurring across its surface during use and formed with cells having anisotropic Young's moduli in the planes perpendicular the central longitudinal axis of each cell can be improved by varying the orientation of the anisotropic cells with respect to one another so as to minimize the number of such cells being oriented with an axis of maximum Young's moduli aligned with the direction of either the maximum temperature difference or maximum localized temperature gradient occurring across the cell.

Abstract: A method of improving the thermal shock resistance of a honeycombed structure through which fluids flow and formed by joining a plurality of cellular segments to one another along their peripheral walls, by providing discontinuities through the joints formed between the adjoining segments in the direction of the fluid flow through the structure so as to lessen temperature differences occurring in the joint area, to provide the structure with greater flexibility and to act as crack arrestors lessening the transmission of stresses between adjoining segments and through the joints. In two preferred embodiments, the invention is practiced in forming a heat recovery wheel by joining a plurality of cellular segments to one another with cement which is striped to the segments so as to form a plurality of hollow, straight walled, channels extending essentially axially through some or all of the joint areas of the resulting wheel.

Abstract: The thermal shock resistance of a honeycombed structure or a structure having a honeycombed surface formed by bonding together a plurality of cellular segments each having a honeycombed face forming a portion of the structure or surface of the structure, respectively, is improved by recessing the bond joints between the joined cellular segments from the surface. The thermal shock resistance of a heat recovery wheel operated in a counterflow heat exchanger system and formed from joined cellular segments is improved by recessing the bond joints joining the cellular segments, preferably approximately one-half inch (12.7 mm), from the face of the wheel exposed to the gases at their highest temperatures.