Moditec srl´s new low-speed granulator, the Goliath Plus, comes with a built-in electronic metal-detection system that protects the machine from damage if metal enters the cutting area.
Moditec of Marennes, France, calls the technology Integrated Metal Detection. It is an option on Moditec´s beside-the-press granulators.
IMD is not a magnetic protection system, said Janet Kevlin, national sales manager for Miami-based Plastec North America Inc., Moditec´s only U.S. distributor.
Kevlin stressed another thing IMD is not: The system is not intended to be the primary piece of metal-detection equipment. IMD´s job is to minimize damage to the cutting chamber by stopping the grinder within 40 milliseconds after metal is detected.
Kevlin said metal contamination is an especially serious issue with low-speed granulators: The knives tend to be expensive to replace because they are machined from solid blocks of steel instead of single strips of metal.
With IMD, the downstroke stationary knives have a zone that is electrically insulated from the rest of the granulator. A programmable logic controller continuously monitors the voltage between the insulated bed knife and the rest of the granulator. If the voltage is less than the set point, the granulator shuts down and an alarm sounds.
Another feature is an anti-blocking system that counts rotor revolutions. If it senses the rotor has stopped, it reverses the rotor, to stop the material and reorient the robot. Plastec said that action permits granulation of heavy cross sections with low speed and low horsepower.
The bed knives on Goliath Plus grinders are reversible and standardized across the line. Goliath Plus granulators are available in five chamber sizes, with single- and dual-rotor models.
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