Automatic changeover of granules in hoppers on plastics processing machines involves extraction of granules until a sensor indicates a specific level in hoppers and then addition of new granules

摘要

Hoppers(3) to be emptied are predetermined and the emptying stage for all hoppers occurs simultaneously by activating the conveying system. When the contents of the hopper have reached a prescribed level indicated by a sensor(18) the conveying system is automatically switched off and new granules re released to refill the hopper. An Independent claim is also included for a granulate hopper whose emptying tube(13) is directed upwards. Preferred Features: Air or conveying screws are used for transporting granules. Hopper emptying cannot be initiated when the filling tube(15) of a container(16) for emptied granulate is correctly set or when the hopper is not open for emptying. Emptying is initiated when a slide restraining new granulate supply is closed and no granulate can flow into the hopper during the emptying period. On completion of emptying, and providing confirmation to refill the hopper is indicated by the control panel, the slide controlling new granulate flow is opened.