Abstract: Device (10) for ultrasonic welding of a flexible, notably tubular, structure (F), to be conformed into sachets, this device including at least two airgaps each defined between a sonotrode (20) and an anvil (30,40) carried by respective support structures (28,54) the distance between which varies between a close together welding position and a spaced apart flexible structure movement position, in which airgaps the flexible structure to be welded is intended to be received to produce at least two weld lines, wherein for each airgap an anvil and/or a sonotrode both associated with this airgap is at least partially mobile relative to a support structure (54) of this anvil or sonotrode.

Abstract: Device (10) for ultrasonic welding of a flexible, notably tubular, structure (F), to be conformed into sachets, this device including at least two airgaps each defined between a sonotrode (20) and an anvil (30,40) carried by respective support structures (28,54) the distance between which varies between a close together welding position and a spaced apart flexible structure movement position, in which airgaps the flexible structure to be welded is intended to be received to produce at least two weld lines, wherein for each airgap an anvil and/or a sonotrode both associated with this airgap is at least partially mobile relative to a support structure (54) of this anvil or sonotrode.