A METAL FLAT DUCT FOR ELBOW

摘要

PURPOSE: A metal flat duct for an elbow is provided to manufacture productions uniformly and circulate air smoothly by having a smooth curved surface-shape. CONSTITUTION: A manufacturing method of a metal flat duct for an elbow comprises next steps. Unit molding plates, which have a curved outer and inner surface with an angle of 45° are formed by molding a galvanized steel sheet. The unit molding plates are faced each other and a curved part of a circumference is connected to be overlapped. An overlapped part is fixed with spot welding and formed into the flat duct for the elbow at 45°. Intervals with a predetermined width are formed in both ends of the unit molding plats for the elbow. Reinforcing grooves protruded from outside are formed and an overlapping connection part is in an outer side of the reinforcing grooves.