FIELD: molding.
SUBSTANCE: invention relates to a rotary joint for transferring melted plastic from at least one extruder to a plurality of moulds of a rotary machine for molding preforms. Joint comprises a fixed structure provided with a fixed longitudinal element therein, defining longitudinal axis (Y), and a movable structure which can rotate about said axis (Y) and is adapted to be integrally fixed to the rotary machine. First passage channel is provided within said fixed element. Second passage channel is provided within said movable structure and coaxial to said first passage channel. Said second passage channel is in communication at a first end thereof with said first passage channel, and is in communication at a second end thereof with a plurality of lateral radial channels provided within said movable structure. There is provided, between the fixed structure and the movable structure, a gap in which a spiral seal is arranged for ensuring the action of sealing the melted plastic between said fixed structure and said movable structure.
EFFECT: invention provides increasing in plant efficiency.
14 cl, 23 dwg
