FIELD: food industry; production of aseptic sealed packs for food products. SUBSTANCE: proposed device has first and second chain conveyors with number of clamps 12 and counter-clamps 13, respectively, for engagement with pipe and clamping the pipe for thermal welding along cross sections. Chain conveyors have members forming semi-moulds which are designed to adjust pack volume and are connected to corresponding clamps 12 and counter-clamps 13. These members engage with corresponding follower 44 to control relative displacement of members forming semi-moulds in direction of trajectory of packing material pipe feeding and from this trajectory. Invention provides control of displacement of semi-mould forming members irrespective of control of displacement of corresponding clamps and counter-clamps. EFFECT: optimum engagement of semi-mould forming members with packing material, provision of perfectly aseptic sealed packs. 10 cl, 14 dwg
