| 摘要 |
A noise cancellation system for transporting a fluid (M) from an inlet in one space (RM1) to an outlet in another space (RM2). A noisy element (VF, HA), e.g. a ventilation fan (VF) or a turbulent noise source (HA), generates acoustic noise. A loudspeaker (L) with a diaphragm (D) is arranged such that a first side (S1) of the diaphragm (D) is in contact with the fluid (M) on a first side (P1) of the noisy element(VF), and a second side (S2) of the diaphragm (D) is in contact with the fluid (M) on a second side (P2) of the noisy element (VF). The loudspeaker diaphragm (D) is arranged to move substantially in anti-phase with at least a part of the noise generated by the noisy element (VF), hereby cancelling the noise from the noisy element (VF). The noisy element may be placed inside a duct system. Especially, the system may be a decentral ventilation system with a noisy ventilation fan (VF) for transporting air between two spaces, e.g. two rooms, or between one room and“free air”. |
