Patent ID: 11047624

Abstract:
Leaking of high-temperature gas inside a furnace to the outside of the furnace via a furnace body opening portion and entry of normal-temperature air outside the furnace into the furnace via the furnace body opening portion are effectively prevented. A central vent that forms an airflow curtain in a target object passage region of a furnace body opening portion and left and right side vents that form airflow curtains respectively in gap regions between the target object passage region and left and right side walls of the furnace body opening portion are provided as vents for forming airflow curtains, an airflow fa for forming an airflow curtain blows from the central vent toward the inner side of the furnace diagonally downward at an inclination angle that is smaller than 40° relative to a horizontal direction, and airflows for forming airflow curtains blow from the left and right side vents vertically downward or toward the inner side of the furnace diagonally downward at an inclination angle that is larger than 60° relative to the horizontal direction.