Abstract: A filter for particle cleaning of impurities in gas flows must be compact and also as effective as possible, including having a pressure drop as low as possible. According to the invention, such filters are composed of three ring-shaped and pleated filter elements, comprising an outermost (4), a middle (5) and an innermost filter element (6) said filters being held together at the inlet side (1, 12) and outlet side (9, 10) of the filter, respectively. Hereby, gas may be supplied to the exterior of the filter as well as to the spaces (8) between the innermost filter element (6) and the middle filter element (5), and this gas will be discharged (14) both from the central filter chamber (15) and from the chamber (17) between the middle filter element (5) and the outermost filter element (4).