| 摘要 |
Within the melt distribution channels, individual melt outlet ends or groups of melt outlet ends are provided with controllable closure units (10) located at a distance from the nozzles (5). Preferred Features: The closure unit (10) for the distribution channel (6) takes the form of a piston (12) movable in a sleeve (11) by the pneumatic or preferably hydraulic piston and cylinder unit (14). Operation of the closure unit takes place by means of a mechanical drive incorporating an electric motor. The closure piston (12) is oriented perpendicular to the distribution channel (6), and has approximately the same diameter as the distribution channel. The closure piston is located in a corner region of the distribution channel. Open nozzles (5) are located at the melt distribution channel outlet ends controlled individually or in groups by closure units (10). The closure pistons can be displaced into intermediate positions between the fully open and fully closed positions. From the fully open position - in which the piston end is approximately flush with the distribution channel surface - the piston can be further retracted through a small distance. In the case where several open nozzles lead into a nest of joined die cavities, each nozzle is provided with its own closure unit.
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