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US 2002/0153199 A1Published application
Sound absorbing foam
OwnerDaniel R. Schroer, Laurent Remy +3inventors
InventorsDaniel R. Schroer, Laurent Remy, Michel Brucker, Chung P. Park, Suresh Subramonian
Life of this patent
Estimating the term…
Abstract
Thermoplastic foams with an average cell size of greater than one and one-half millimeters and an average noise reduction coefficient in excess of 0.3 have improved sound attenuating properties when they include a Helmholtz resonator, a quarter-wave attenuator or both.
Claims10
An improved, sound-attenuating cellular thermoplastic polymer foam body, the modified foam body having
- a. an average cell diameter of at least one and one-half millimeters;
- and
- b. an impedance tube noise reduction coefficient of at least 0.3, wherein the improvement comprises at least one Helmholtz resonator, each Helmholtz resonator being disposed within the foam body, having a neck in fluid communication with an external surface of the foam body and being spaced apart from each other, whereby each Helmholtz resonator improves sound absorption coefficients about a Helmholtz center peak frequency band, such that at least one adjacent octave band has a sound absorption coefficient within 0.4 units of a peak sound absorption coefficient and increases the impedance tube noise reduction coefficient by at least 0.1 relative to the impedance tube average noise reduction coefficient of the same foam body without any Helmholtz resonators.
An improved, sound-attenuating cellular thermoplastic polymer foam body, the foam body having
- a. an average cell diameter of at least one and one-half millimeters and
- b. an impedance tube average noise reduction coefficient of at least 0.3
- wherein the improvement comprises at least one quarter wave attenuator, the attenuator(s) being spaced apart from each other and having a diameter that exceeds the average cell diameter, each attenuator beginning at a surface of the foam body and extending into, but not through, the foam body, whereby the quarter wave attenuator(s) increase(s) the impedance tube average noise reduction coefficient by at least 0.1 relative to the impedance tube average noise reduction coefficient of the same foam body without any quarter wave attenuator(s), and each quarter wave attenuator improves sound absorption coefficients about a quarter wave attenuator center peak frequency band, such that at least one adjacent octave band has a sound absorption coefficient within 0.4 units of a peak sound absorption coefficient.
Dependencies are inferred from the claim text.