Abstract: A silencer for a ventilation system, for example a gas turbine air intake system, includes first and second body sections spaced from each other to define a gas flow path therebetween. Methods of attenuating noise from a gas turbine air intake includes directing air from a dirty air plenum of a gas turbine air intake system through an air flow path defined by first and second body sections.

Abstract: A fluid cleaner device to be used for retaining the dust and contaminants of a fluid, such as the combustion air for an internal combustion engine, comprises a plurality of parallel cleaning cells or units each consisting of a main filter for arresting and collecting the dust and contaminants contained in the fluid to be cleaned, and at least one respective safety filter which is able, in the event of a fissure in the main filter to retain the dust and contaminants not collected upstream by the main filter. The safety filter is a structure that when through crossed by the cleaned fluid induces only low pressure losses, but is rapidly clogged by the dust and contaminants passing through a fissure in the main filter, so that the flow of the fluid to be cleaned which escapes the main filter is rapidly stopped and diverted to other normally functioning cleaning units.