A silencer device for attachment to a nozzle, or a combined nozzle and silencer, are provided for reducing the noise generated by compressed air or a compressed air-particulate mixture exiting from conventional nozzles of the type used for air blasting, sandblasting, or peening operations. The silencer...http://www.google.com/patents/US3982605?utm_source=gb-gplus-sharePatent US3982605 - Nozzle noise silencer
