Patent ID: 6920959
Filing Date: 2005-07-26
Classification: F04D,F23L,Y10S

Abstract:
1. A sound attenuating duct unit for delivery of air or gases to an inlet of a fan unit, said duct unit comprising: an elongate duct for transferring air or gases to said inlet, said duct having duct walls and including a narrow first section, a second, transition-type, expanding section having one end connected to an adjacent end of said first section and an opposite second end, and a relatively wide, sound attenuating third section connected to said second end of the second section, said elongate duct being adapted to extend substantially vertically with said first section on top and said third section at a bottom end thereof, said third section having two opposite first and second side walls that taper towards each other in the direction of air or gas flow through said elongate duct, said direction being downwardly during use of said duct unit, said third section also having a plurality of spaced-apart splitters containing sound attenuating material and having at least two opposing sidewalls made of perforated sheet metal, said splitters being substantially planar, being elongate in said direction of air or gas flow, and being connected to said duct walls, said splitters including at least one central splitter and outer splitters and said outer splitters converging inwardly towards a central longitudinal axis of said third section from their upstream ends to their downstream ends, said central longitudinal axis extending at an acute angle to a vertical axis intersecting said central longitudinal axis; and an elbow-shaped duct section having an upstream end adapted for connection to said third section and a downstream end adapted for connection to said air supply fan unit.