Abstract: The invention relates to a method for making the drying of materials, particularly finely divided materials, more effective, in which method, of a slurry containing liquid and solids there is made a filter cake (2,12,22) onto the surface of the filter medium (1,11,21). According to the invention, the filter cake (2,12,22) and the oscillator (6,15,25) are arranged, in relation to each other, so that in between the filter cake (2,12,22) and the oscillator (6,15,25), there is generated an acoustic field by virtue of a mechanical contact between the filter cake (2,12,22) and the oscillator (6,15,25) or a structural element (7,16,26) connected to the oscillator.

Abstract: Method in a suction dryer (10), which comprises a basin (12) for a suspension to be suction-dried, in connection with which basin one or several filter-plate discs (14a) revolve, onto whose faces a filtrate cake is gathered and dewatered by the effect of a suction flow passing through the filter plates (14a), the said filtrate cake/cakes being scraped or otherwise detached from the faces of the filter plates (14a). For the purpose of cleaning the porous structure and faces of the filter plates (14a), an ultrasonic detector or detectors (30) are provided in connection with the basin (12) for the suspension to be filtered, to which detectors an electric power of ultrasonic frequency is fed from an ultrasonic generator (32). For the time of the cleaning intensified by ultrasound, the suspension basin (12) is filled with a connecting and cleaning liquid, e.g. water.