Sound absorbent

Abstract

A light absorbent for hygienic spaces comprising a porous mat. The normalized flow resistance of the mat is in the interval of 0.5-2.

1 . A sound absorbent for hygienic spaces comprising a porous mat ( 1 ), characterized in that the normalized flow resistance of the mat is in the interval of 0.5-2.  
     
     
         2 . A sound absorbent according to  claim 1 , characterized in that the mat ( 1 ) comprises a plurality of long threads compressed into a thin sheet.  
     
     
         3 . A sound absorbent according to  claim 2 , characterized in that the threads are manufactured from a plastic material.  
     
     
         4 . A sound absorbent according to  claim 3 , characterized in that the plastic material is a polyester.  
     
     
         5 . A sound absorbent according to any of the preceding claims, characterized in that the sheet is reinforced by a net of a shape-permanent material.  
     
     
         6 . A sound absorbent according to any of the preceding claims, characterized in that the absorbent comprises a foil making free contact with the mat.  
     
     
         7 . A sound absorbent according to  claim 1 , characterized in that the absorbent, at high gas temperatures, comprises a perforated sheet.  
     
     
         8 . A transport system for a gaseous medium comprising a plurality of channel sections, whereby at least a first channel section comprises an absorbent, characterized in that the absorbent is thin and its normalized flow resistance is in the interval of 0.5-2.  
     
     
         9 . A transport system according to  claim 8 , characterized in that the thickness of the absorbent is smaller than one-twentieth of the channel dimension.  
     
     
         10 . A transport system according to  claim 8 , characterized in that absorbent comprises a mat of compressed long threads of polyester.  
     
     
         11 . A transport system according to any of claims  8 - 10 , characterized in that absorbent is reinforced by a net of a shape-permanent material.  
     
     
         12 . A transport system according to any of claims  8 - 11 , characterized in that absorbent is placed at a distance along the walls of the channel.  
     
     
         13 . A transport system according to any of claims  8 - 12 , characterized in that absorbent forms guide vanes in the channel section.  
     
     
         14 . A method for manufacturing an absorbent for hygienic spaces comprising a porous mat, characterized in that the normalized flow resistance of the mat is arranged in the interval of 1-2.  
     
     
         15 . A method according to  claim 14 , characterized in that the mat is arranged from a plurality of long threads which are compressed into a thin sheet.  
     
     
         16 . A method for manufacturing an absorbent comprising a plurality of channels with a characteristic diameter influencing a resistive part of the normalized flow resistance and a characteristic length influencing a reactive part of the normalized flow resistance, characterized in that, within a desired frequency range, the characteristic diameter is influenced such that the resistive part of the normalized flow resistance is within the interval of 0.5 to 2, and that the characteristic length is influenced such that the reactive part of the normalized flow resistance is limited by the resistive part.  
     
     
         17 . Use of an absorbent according to claims  1 - 7 , a transport system according to claims  8 - 13 , a method according to claims  14 - 15 , or a method according to  claim 15  in a ventilation plant.