To obtain a high heat transfer efficiency by preventing the bias flow of gas.
This checker brick 1 is a tubular body, whose upper and lower ends are opened and whose section is right pentagonal shape while being constituted of eight pieces of rectangular side walls 11, 12, 13, 14, 15, 16, 17, 18. Slanted parts 11e, 13e, 15e, 17e for forming an expanding space for generating eddy flow in gas are provided on the inner peripheral surfaces 11b, 13b, 15b, 17b. Four pieces of checker bricks 1 are arranged annularly on the same plane so that the side walls 11 become parallel to each other and another checker brick, having the same structure, is put on the center of these bricks 1. The side walls of bricks in an upper stage are supported respectively by the side walls 15, 17, 11, 13 of four pieces of the bricks 1 in a lower stage. The expanding space is formed between the slanted surfaces of the bricks in the upper stage and the upper surfaces of the bricks 1 in the lower stage.
IMAI ISAO
KAI SETSUO
