RADIANT TUBE

WIPO Patent Application WO/2021/166651

A1

Provided is a radiant tube that is of a simplified structure and that has a heat transfer enhancement body capable of achieving a higher heat-transfer efficiency. A heat transfer enhancement body (4) comprises: a body part (41) that is disposed on the center side of a pipeline (1); and a plurality of projecting parts (42) that protrude from the body part (41) toward the inner wall surface (1a) of the pipeline (1). The plurality of projecting parts (42) are formed on the outer circumference of the body part (41) so as to be arranged in the circumferential direction of the pipeline (1). Said projecting parts (42) include a plurality of first projecting parts (42a) opposing the inner wall surface (1a) of the pipeline (1) across a gap (ΔL) with the remainder being second protruding parts (42b). The first projecting parts (42a) are provided in a quantity greater than that of the second projecting parts (42b). When the ratio (ΔL/Dt) of the gap to an equivalent diameter of the pipeline (1) portion where the heat transfer enhancement body (4) is disposed is defined as x[%] in percentage, expression 0.3%