Device for distributing thermoplastic material with improved seal

Device (10, 210) for distributing thermoplastic material to a preform molding machine designed for the manufacturing of containers, with said device (10, 210) comprising at least one stationary part (12, 212) and one movable part (14, 214) that is driven in rotation in relation to said stationary part (12, 212) around an axis (X) of the device and comprising a seal (50, 250) arranged between at least the stationary part (12, 212) and the movable part, wherein:

• the stationary part comprises at least one feed inlet (E) connected to a source for supplying thermoplastic material and the moveable part (14, 214) comprises at least one outlet (S) for distributing said thermoplastic material to units of said preform molding machine
• said seal (50, 250) comprise a first sealing surface (52, 252) that is integral with the stationary part (12, 212) and a second sealing surface (54, 254) that is linked in movement to the movable part (12, 214), with said first and second sealing surfaces extending radially along a seal plan perpendicular to said axis of the device and being separated axially from one another by a gap (56, 256) into which can flow a portion of the thermoplastic material in circulation between the feed inlet (E) and the at least one outlet (S),
• the movable part (14, 214) comprises a pipe (20, 278) connected to said at least one distribution outlet (S), the pipe (20, 278) having a gap opening into the gap (56, 256), the fixed part (14, 214) being arranged so that the thermoplastic material coming from the supply inlet (E) penetrates the gap opening having passed through the seal (50, 250),
• at least one of said first and second sealing surfaces (52, 54, 252, 254) comprising channeling (58, 268) structured for radially constraining the thermoplastic material of the seal when the movable part (14, 214) is driven in relation to the stationary part (12, 212) and
• said seal (50, 250) comprises at least one associated cooling circuit (60, 260) located radially remote from the gap opening (20a, 280) to obtain a temperature of thermoplastic material of the seal considered at a radial distance from the gap opening follows a temperature gradient along a radial direction in order to increase the viscosity of said thermoplastic material to form the seal as the radial distance increases.