What's New » Guangzhou - Maguire Asia cites new uses where LPD™ vacuum dryer yields special advantages over hot air/desiccant systems

Guangzhou - Maguire Asia cites new uses where LPD™ vacuum dryer yields special advantages over hot air/desiccant systems


GUANGZHOU, June 21, 2005 - With sales of the LPD™ vacuum resin dryer now growing so rapidly that more than 1,000 units of the new system are already in operation, Maguire Asia has identified still more applications where the unique vacuum drying concept provides important advantages over conventional hot air / desiccant dryers, the company announced today at Chinaplas 2005 (Stand C 756). 

"Although the LPD dryer became commercial less than five years ago and represents a radical departure from conventional systems, hundreds of custom molders and extrusion processors throughout the world have proved for themselves that this system actually does require only one-sixth of the time and 20% of the energy to dry resin properly," said Hubert Nerlich, managing director of Maguire Asia. "Now it is becoming clear that the LPD dryer also provides dramatic increases in productivity and reductions in cost for certain operations that pose special challenges to any drying equipment."
Nerlich cited these emerging applications for the LPD dryer, all of them demonstrated by customers in commercial processing operations:

Environments with high humidity. "Desiccant dryers used in conditions of high relative humidity work extra hard because they must remove moisture from both ambient air and resin," Nerlich noted. "Often the result is improper drying and high reject rates. A vacuum dryer, however, removes ambient air from the drying canister, eliminating its effect on the drying process." 

PET preforms and bottles. "The availability of high-capacity models of the LPD dryer is a real breakthrough for producers of PET performs and bottles, because vacuum drying subjects resin to 85% less exposure to elevated temperatures than conventional hot air/desiccant dryers," Nerlich said. "This means substantially less property degradation as measured by falloff Maguire Asia Cites New Uses Where LPD™ Dryer Yields Special Advantages - 2 in intrinsic viscosity and by discoloration. By thus reducing the heat history undergone by the resin, LPD dryers reduce the production of reject bottles." 

Production volumes for PET bottles are typically very high. For such applications, Maguire provides the LPD-1000 model, which accommodates processing machine throughputs up to 450 kg/hr (1,000 lb/hr). A model with even larger throughput is in development.

Wood composites and other materials with high moisture content. In the fast-growing field of plastics / wood-fiber composites, moisture levels of wood flour can range from 3 to15%, quickly saturating desiccant so that conventional dryers cannot maintain air at the required low dew point, according to Nerlich. With a vacuum dryer, however, wood flour dries properly in only about 40 minutes 
Resins that embrittle if they are over-dried. When nylon is dried to a moisture level closely approaching zero, it becomes brittle and produces serious defects in the finished product. "Since a desiccant dryer running continuously will remove moisture until none at all is left, a prolongation of the drying cycle caused by a processing-machine stoppage can result in nylon that is over-dried," Nerlich said. "This cannot happen with the LPD dryer. Because the vacuum in the drying canister is not quite at full vacuum and retains a thin atmosphere, there is always a bare minimum of moisture left in the system. The moisture levels inside and outside the resin pellets eventually reach equilibrium at a tiny fraction of a percent that is, however, above the level where there is a risk of embrittlement."

The advantages provided in these applications result from radical differences between the LPD and conventional dryers: 1) instead of flowing hot, dry air over the pellets to slowly draw the moisture out, the LPD dryer uses vacuum to reduce the boiling point of water, quickly turn moisture into water vapor, and literally pull the water vapor from within the pellets; and 2) the LPD dryer carries out heating and vacuum drying simultaneously in three separate indexing stations, making possible small batches while in effect transforming a batch process into a continuous one that keeps pace with the throughput of the processing machine.


MAGUIRE PRODUCTS, INC., headquartered in Aston, Pennsylvania, U.S.A., is the world’s largest supplier of gravimetric blenders and liquid color pumps and also manufactures loading Maguire Asia Cites New Uses Where LPD™ Dryer Yields Special Advantages - 3 systems, granulators, dryers, auger feeders, and related equipment and software. Its customers include injection, blow, and rotational molders, extrusion processors, and compounders. Founded in 1977, Maguire operates five manufacturing facilities in Aston and Smithfield, Rhode Island, U.S.A. The company maintains a network of distributors in the Americas and overseas and has two sales and service subsidiaries: Maguire Europe, which supports customers throughout Europe and operates a distribution center in Tamworth, Staffordshire, United Kingdom; and Singapore-based Maguire Asia, serves customers throughout South Asia and the Pacific Rim. Visit the Maguire Products web site: www.maguire.com.

Maguire Asia / Headquarters: Maguire Products Asia Pte Ltd., 45 Kallang Pudding Road, No. 01-02 Alpha Building, Singapore 349317. Tel: 65-6848-7117. Fax: 65-6744-3370. Contact: Hubert Nerlich, managing director, via email at magasia@singnet.com.sg.

Maguire Asia / Shanghai office: Maguire Products Asia Co. Ltd., Majesty Building 7F, Room C-02, 138 Pu Dong Avenue, Shanghai 200120 China. Tel: 86-21-58823410. Fax: 86-21-58823420. Contact: Marshall Guo at mpa@maguirechina.com. 

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