Passive sound impedance reducing noise - has central vol. with vapour and fluid phase mixture in state of thermal equilibrium

摘要

A passive type sound prevention impedance is used to diminish or minimise the emission of noise from a source. It has a central volume or space (2) filled with a thermodynamically equilibrated vapour/fluid phase mixture and surrounded by a sound transmitting medium. The mixture is in thermal equilibrium to produce a vapour/condensation equilibrium. The sound transmitting medium is in the form of a low mass membrane (1). The fluid/vapour mixture consists of a miscible and/or immiscible material mixture.