Patent Number: 6,167,984

Title: Device and a method for sound reduction in a transport system for gaseous medium and use of the device in an exhaust system for ships

Abstract: A device and a method for achieving sound reduction within a frequency band in a transport system for gaseous medium, the transport system being arranged between an inlet, which is connected to a sound source, and an outlet. The transport system comprises with a plurality of interconnected channel parts (1-7) and exhibits at least one module (8, 9) comprising at least one reflection attenuator (4) with a resistive length (a.sub.2, b.sub.2) and at least one reactive attenuator (3) with a reactive length (a.sub.1, a.sub.3, b.sub.1, b.sub.3). The resistive length is brought to constitute a quarter of a wavelength of the center frequency of the frequency band and the reactive length is brought to constitute a quarter of a wavelength of a frequency between, respectively, the lower and upper limit frequencies of the frequency band.

Inventors: Johansson; Claes-Goran (Vaster.ang.s, SE), Gotmalm; Orian (Kullavik, SE)

Assignee: ABB Flakt AB

International Classification: F01N 1/02 (20060101); F01N 1/04 (20060101); F01N 1/06 (20060101); F01N 7/00 (20060101); F01N 7/02 (20060101); F01N 1/00 (20060101); F01N 007/02 ()

Expiration Date: 01/02/2018