The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 02, 2001
Filed:
Aug. 13, 1999
Claes-Göran Johansson, V{umlaut over (a)}sterås, SE;
{umlaut over (O)}rian Götmalm, Kullavik, SE;
ABB Flakt AB, Stockholm, SE;
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 (,) and exhibits at least one module (,) comprising at least one reflection attenuator (,) with a resistive length (a,, b,) and at least one reactive attenuator (,) with a reactive length (a,, a,, b,, b,). 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.