US Patent 9381787 Generally wye shaped elbow for cabin air flow system

An elbow for use in a cabin air supply system for an aircraft has an inlet duct. The inlet duct diverges into two outlet ducts with an interface area between the outlet ducts. Each of the outlet ducts has a nominal wall thickness, with a central portion of the interface having a first thickness at a point of maximum thickness, and the nominal wall thickness being of a second thickness. The central portion of the interface curves to the central portion of the interface area. A ratio of the first thickness to the second thickness is between 3 and 8. A cabin air supply system is also disclosed.