A silencer that comprises a casing, one or more pipes or passages leading a flow of gas to the casing and a device for leading gas from the casing. The silencer further has at least one internal chamber, one or more flow inlets to the chamber and one or more flow outlets from the chamber, and one or more flow distributing devices connected to the flow inlet(s) and/or to the flow outlet(s). The flow distributing device comprises one or more walls or profiles extending on a geometrical surface that defines a boundary between an inner volume of the flow distributing device and the chamber. The silencer further has one or more apertures for a flow of gas through the apertures and for leading gas either out of the inner volume into the chamber, or into the inner volume from the chamber. The apertures have a smallest cross-sectional transverse dimension s and a length L, the dimension s being at the maximum 0.2 times the smallest cross-sectional dimension D of the inlet or outlet. The length L is at least the same as the dimension s.