Gas flow duct e.g. for i.c. engine turbo-charger has multiple-hole slencer and two quarter-wave attenuators to reduce noise level

摘要

A duct (1) has a range of acoustic attenuators extending laterally from an intermediate segment (4) and comprising a multiple-hole silencer (2) and two quarter-wave attenuators (3, 3') that are positioned so as to be coupled acoustically to the silencer. The duct (1) has a range of acoustic attenuators extending laterally from an intermediate segment (4) and comprising a multiple-hole silencer (2) and two quarter-wave attenuators (3, 3') that are positioned so as to be coupled acoustically to the silencer. The intermediate segment is more or less straight, with the silencer and attenuators located on opposite sides of its lengthwise median axis. The silencer is in the form of a flat hollow housing (5) that is connected to the interior of the duct through a series of holes, and the components can be made from metal or injection-moulded thermoplastic(s) with optional fibre reinforcement.