Monolithic refractory recuperator

A heat recuperator comprising:

• a monolithic block containing a first array of a plurality of tapered waste gas passages therethrough and a second array of a plurality of tapered combustion air passage segments therethrough, said combustion air passage segments being oriented in a direction substantially perpendicular to said waste gas passages, said block being formed as a unit in a single casting;
• and
• at least one turnaround manifold containing at least one passage for interconnecting a pair of combustion air passage segments, said manifold being coupled to a surface of said monolithic block in such position as to interconnect a pair of combustion air passage segments, thereby forming a multiple-pass combustion air passage.

A heat recuperator comprising:

• a monolithic block containing a first array of a plurality of waste gas passages therethrough and a second array of a plurality of combustion air passage segments therethrough, said combustion air passage segments being angularly displaced from one another in order to preclude parallel adjacent segments and being oriented in a direction substantially perpendicular to said waste gas passages, said block being formed as a unit in a single casting;
• and
• at least one turnaround manifold containing at least one passage for interconnecting a pair of combustion air passage segments, said manifold being coupled to a surface of said monolithic block in such position as to interconnect a pair of combustion air passage segments, thereby forming a multiple-pass combustion air passage.