| 摘要 |
A duct is formed by using a protruding plate in the present invention. The duct has improved strength and low thickness. The duct according to the present invention is formed with a protruding plate having the embossed surface. The duct is preferred to have the protruding plate formed to have a flat plate be embossed. The flat plate has high strength compared with a flat plate. According to the present invention, the duct is formed by using the protruding plate, thereby increasing the strength of the duct. The thickness of the protruding plate is reduced to lighten the duct. |
