Patent ID: 11869470
Assignee: FUJIFILM CORPORATION
Field: Thermal processes and apparatus (Mechanical engineering)
Classification: CPC G  F | IPC F  G

Claim 0:
1. An acoustic system comprising:
a duct that has a function of causing a fluid to flow therein and has a tubular shape;
an internal sound source that is disposed inside the duct or at an outer peripheral portion of the duct, which communicates with an inside of the duct, or an external sound source that is on an outside from an end portion of the duct; and
a membrane-shaped member that is formed as a part of a wall of the duct and vibrates in response to sound,
wherein a structure including the membrane-shaped member and a rear surface thereof causes acoustic resonance to occur, transmits the acoustic resonance from the sound source into the duct, and suppresses sound radiated from the other end portion of the duct,
the external sound source is at a distance within a wavelength at a frequency of the acoustic resonance on the outside from the end portion of the duct, and
for at least one membrane-shaped member or at least one membrane-type resonance structure, in a case where a wavelength determined from a frequency at which a sound pressure of sound generated by the sound source is maximum is denoted by λ and an integer of 0 or more is denoted by m, a center of the membrane-shaped member is positioned at a distance which is larger than (m×λ/2−λ/4) and is smaller than (m×λ/2+λ/4) from a position of the sound source.