Pellet Dryer Reduces Cost of Wear From Abrasive Compounds

A new-design pellet dryer for use with Nordson Corp.’s BKG pelletizing systems reportedly meets the challenge posed by the steady growth in use of glass-filled and other abrasive materials by substantially reducing the time and cost associated with replacing “wear” parts.

The design reduces the number, complexity, and cost of the dryer components that are subject to abrasion and makes them more accessible to maintenance or replacement. While the new dryer has much the same overall appearance and footprint as a standard BKG dryer and provides the same throughput, there are substantial differences in the configuration of components subject to wear. The new design reduces production downtime by simplifying maintenance, making it possible for one person to carry out maintenance tasks.

“We have seen a reduction in maintenance times by up to 70%,” notes Matthias Köhler, operations manager at the Domo Engineering Plastics GmbH facility in Premnitz, Germany. “It is now possible to determine concrete maintenance intervals, so downtime becomes more plannable and less unexpected.” Domo, an initial user of the new pellet dryer, installed the unit on an existing underwater pelletizing line that processes polyamide 6 compounds with up to 50% glass fiber content.

Frank Asmuss, Nordson global product manager for BKG pelletizers, cites a number of design enhancements for reducing wear or simplifying maintenance:

● Pellet inlet: “As a result of a new design made in accordance with flow simulations, the inlet now enters the dryer housing tangentially, reducing the impact on all parts in the lower part of the dryer, and allowing quick access to all remaining wear parts,” Asmuss notes.

● Rotor: Due to the optimized pellet inlet, the rotor has been simplified, especially in the lower area, and wear is minimized by the reduced impact of abrasive pellets. Other measures taken to reduce or eliminate wear from pellet flow include a new cover plate design and countersinking of screw heads. Ausmus says, “In standard dryers, rotor disassembly and reassembly took ten hours; the new design reduces this time to about three hours.”

● Pellet outlet: The new design includes fewer wear parts, and these are more accessible. Disassembly/reassembly time has been reduced from 6 hours to a range of 1 to 4 hours.

“The design changes we made to reduce wear led to significant overall savings per ton of glass fiber filled product,” states Asmuss. “In combination with the reduced maintenance time, the overall operating costs for the dryer were decreased significantly, which is a big benefit for our customers.”