Patent ID: 8267759

Claim:
A method of exhausting into a generally rectangular and vertical main shaft, the method comprising the steps of: providing a sub-duct comprising: a hollow first portion presenting an attaching wall, a rectangular cross-section, a top side of the rectangular cross-section defining a top side opening, and a bottom side having a rounded configuration; and a hollow second portion defining an intake opening and meeting with the first portion attaching wall at approximately a ninety degree angle, the first and second portions collectively defining a continuous channel between the intake opening and the top side opening; providing an exhaust duct; coupling the sub-duct attaching wall flush with an inner wall of the main shaft wherein the entire hollow first portion is inside the main shaft, the sub duct being aligned in a generally vertical direction with the top side opening being above the bottom side and the second portion; coupling the exhaust duct to the sub-duct second portion; passing exhaust from the exhaust duct through the sub-duct intake opening, continuous channel, and top side opening, and into the main shaft, the exhaust being passed directly from the top side opening to the main shaft without further guidance from the sub-duct.