| 摘要 |
A radiant tube made of refractory metal is provided with at least one bent tube (3A (3C)) which connect straight tubes (2A, 2B (2C, 2D)). Combustion air from a burner (5) is fed through one of the straight tubes (2A, 2B (2C, 2D)), and the radiant tube is characterized by using a cast product with an external diameter of 150 - 210 mm and a thickness of 3 - 8 mm at least as the bent tube (3A (3C)) closest to the burner (5). |
