Method and apparatus for exhausting air from a limited zone

摘要

Exhaust from a limited zone lying on the axis of a cylindrical exhaust duct and spaced from an unobstructed entrance opening of the duct is produced by injecting a flow of air radially outward from a circumferentially extending aperture surrounding the entrance to the exhaust duct while at the same time sucking air through the unobstructed opening of the exhaust duct.