Patent ID: 8479879

Claim:
An expandable chamber acoustic silencer, comprising: a substantially closed container having at least one fixed wall portion, at least one movable wall portion, and at least one flexibly expandable portion between the fixed wall portion and the movable wall portion, the fixed wall portion, the movable wall portion, and the flexibly expandable portion defining a variable internal cross-sectional area for the container, the container further having an inlet passage and an outlet passage, the inlet passage and the outlet passage each having a fixed cross-sectional area, the inlet passage and the container defining an expansion chamber, wherein at least one actuator housing is formed within the at least one fixed wall portion, the at least one actuator housing being in open communication with the at least one flexibly expandable portion; at least one microphone mounted to the container; an actuator controller, the controller receiving signals from the microphone; and at least one actuator being received within the at least one actuator housing, the actuator receiving signals from the controller and adjusting the at least one movable wall portion relative to the at least one fixed wall portion, and thereby the corresponding internal cross-sectional area of the container relative to the fixed cross-sectional areas of the inlet passage in accordance with the signals received from the controller to automatically adjust acoustic transmission loss in the expansion chamber to changes in noise level.