Abstract: This invention is related to a process for filtering gases or liquids for removing liquid or solid impurities and is characterized in that one uses for filtering a fibre material which partly exhibits a layer structure, said fibres along the main part of the total fibre length exhibiting a direction which deviates less than 45.degree. from the direction of a main direction plane of said fibres, said filtering being performed so that the filtered medium is brought to flow away from the filter material through an outflow area in the filter material in which the flow direction is essentially parallel with the direction of the main direction plane of the fibres.