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Panel that absorbs acoustic energy at low, medium and high frequencies, particularly at frequencies ranging from 400 Hz to 5,000 Hz

  • US 5,493,081 A
  • Filed: 07/29/1994
  • Issued: 02/20/1996
  • Est. Priority Date: 08/06/1993
  • Status: Expired due to Term
First Claim
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1. A panel absorbing acoustical energy at low, medium and high frequencies ranging from 400 Hz to 5,000 Hz, which comprises a plate (1) of semi-rigid foam with open communicating cells and a layer (2) of bonded fibers or a flexible cellular material superposed on and secured to said plate (1) to form an assembly, the assembly acting according to a mass-spring principle, or wherein the foam of the plate (1) is a semi-rigid polyurethane foam of a density ranging from 20 Kg/m3 to 50 Kg/M3, of a thickness ranging from 5 mm to 15 mm and whose permeability to air ranges from 5 liters per minute to 45 liters per minute for a specimen 80 mm in diameter.

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