PURPOSE: To realize a great deal of reduction of NOx formation by providing a cooling fin with colliding and dispersing functions of secondary air and combustion gas.
CONSTITUTION: A cooling fin 5 is provided and tilted so as to form inside a secondary air introduction passage 7 which opens a secondary air introduction port 6 at a lower end and gets narrower toward upward, and has a secondary air hole 8 on its tilting surface. The cooling fin 5 is arranged above the secondary air passage 6 between combustion tubes 1. By this, secondary air jetted out of the secondary air hole 8 in the cooling fin 5 collides dispersedly and burns, whereby flame temperature is lowered by the cooling fin 5, and also generation of NOx can be decreased by a great deal.
SHIMAZU MASAHIKO
OKADA HIDEYUKI
UEDA HIDEO
