Method for producing membrane wall, pipe bending device for manufacturing transfer duct and method for manufacturing transfer duct using same

A method for manufacturing a transfer duct, the method comprising:

• forming a unit pipe assembly by coupling a pair of pipes to each other in a longitudinal direction through a pin;
• propelling the unit pipe assembly into a space between a movable bending tool and a counter tool;
• pressing the unit pipe assembly with a predetermined curvature by moving the movable bending tool to a predetermined position while bringing a surface of the unit pipe assembly into contact with inclination surfaces of the movable bending tool and the counter tool;
• and
• forming a cylindrical duct having a curved part by coupling unit pipe assembles, which are bent in the bending of the unit pipe assembly, to each other,
• wherein the pressing the unit pipe assembly with the predetermined curvature simultaneously bends the unit pipe assembly at a predetermined angle of twist according to an inclination angle of the inclination surfaces.