FILTER PLANT FOR FILTERING A GAS FLOW

The filtration device for filtering a gas stream, in particular for filtering gases generated by a gas generator for an impact protection pad, has a filter element with a plurality of filter material plies of different permeability, located one after the other in the direction of flow. The filter element is formed as a wound body (38) which has been formed by winding up a web of filter material. The filter material web contains filter materials, which differ section by section, preferably wire netting of different mesh widths, and metal fibre mats. Winding-up of this filter material web produces a wound body (38) whose windings consist of different materials having different filter actions. This wound filter element body (38) is inserted, for example, into the annular interspace between the two tubes (12, 14) of a twin-tube gas generator. Due to the rise in pressure of the gas to be cleaned, the wound body (38) is compacted, with the consequence that the filter function is improved. ……