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VIDEO: The Maguire Purging Recovery System
Maguire Products, Inc. claims it has streamlined the operation of its system for recycling purgings into regrind, offering potential increases in throughput of 20% and production of finer and more uniform granulate with less dusting. The group has received the CE certification required to make the system available in Europe.
The modifications to the Maguire Purging Recovery System (PRS) may also benefit the granulation of polystyrene, flexible vinyl, and other polymers that might otherwise melt or degrade under the forces of size reduction, causing backup or clumping that shuts the system down.
In the PRS, material undergoes two stages of size reduction. First, a rotor planer slices or planes the rock-like purging into small chips. Next, a granulator reduces the chips to regrind.
The knives in the rotor planer are now 40% smaller, while their number has increased from eight to twelve. As a result, the planer produces smaller chips that are more easily and uniformly reduced by the second-stage granulator. The cutting also yields less dust than in the previous version.
The cutting chamber of the second-stage granulator has been redesigned to increase the flow of air generated by a blower. The material in the granulator is thus cooled more effectively, preventing melting, and it is evacuated from the cutting chamber more rapidly.
These enhancements make possible finer granulate, with minimum hole sizes in the screen of the second-stage granulator reduced from 9.52mm to 6.35mm. In a further improvement, Maguire has replaced the previous one-piece screen with a three-piece screen that is easier and less expensive to replace.
Typically a purging is discharged onto the shop floor, hardens, is scraped up, and is disposed of, ultimately ending up in landfill. Over time, this adds up to a waste of material valued at thousands of dollars per year, claims Maguire.
“Our PRS system is the only low-cost equipment designed specifically for the rugged work of size-reducing heavy masses of plastic,” said B. Smith, Marketing and Sales at Maguire. “Since a 4.5kg lump of hard plastic could damage the rotor of a conventional granulator, the only other alternative for reclaiming pur gings is to purchase a heavy-duty granulator for $100,000 to $200,000.”
The Purging Recovery System draws on the concept of the carpenter’s plane. It consists of a table that is split into two levels and a purging containment chamber that, upon startup of the system, moves back and forth over the table. The planer, mounted at the point of disjunction between the two surface levels, is actually a rotor with staggered knives that turns at 1750 r.p.m. With each pass of the containment chamber, the rotor planes away thin (13mm) slices from the bottom of the purging and propels these chips into the hopper of a compact granulator beneath the table. As material is planed away from the purging, a pneumatically-driven hold-down plate in the containment chamber keeps the purging in contact with the knives.