DRYER DRAMATICALLY CUTS ENERGY COSTS AND RESIN HEAT HISTORY FOR HIGH-THROUGHPUT
June 23, 2003
new model of the Maguire® Low Pressure Dryer™ (LPD™) with five times the
maximum capacity of the next-largest LPD unit makes the substantial cost
savings, reduced heat history, and other advantages of vacuum drying available
to a vast new range of plastics processors, it was announced today by Maguire
Products, Inc., which is introducing the model at NPE 2003 (Booth 9101).
new Maguire LPD-1000 resin dryer accommodates processing machine throughputs up
to 1000 lb/hr. (450 kg/hr). Like
smaller LPD models, it requires one-sixth of the time and as little as 20% of
the energy needed by conventional hot-air/desiccant dryers to properly dry
resin. Until now, these advantages
were unavailable for processing operations with hourly outputs in the range of
200 (90 kg) to 1000 lb. Some
examples of such operations are:
(PET) preforms and bottles. While
throughputs of these parts typically exceed 500 lb. (225 kg) per hour, until now
the highest-capacity LPD dryer was the LPD-200, for throughputs up to 200 lb.
(90 kg) per hour.
▪ Large-part injection molding, such as processes often employed for automotive parts.
▪ High-volume extrusion of sheet, film, and other products.
availability of a high-capacity vacuum 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," said B. Patrick Smith, vice president of sales and marketing.
"This means substantially less property degradation as measured by
falloff in intrinsic viscosity and by discoloration."
Dimensional Scale-Up with Capacity Increase Is Less
than for Desiccant Dryers
increase in throughput between the LPD-200 and the LPD-1000 is five-fold, the
scale-up in dimensions is proportionally less.
The new dryer is 58 in. wide, 58 deep, and 80 high (147 by 147 by 203
cm), compared with 31 by 32 by 70 in. (79 by 81 by 178 cm) for the LPD-200.
The LPD-1000 can be deployed as a beside-the-press dryer, be
mezzanine-mounted above the processing machine, or serve as a central unit
equipped with multiple take-away ports for multiple processing lines.
lowest-capacity LPD dryer is smaller to start with than a conventional dryer of
equivalent throughput rating, and the difference becomes greater as capacity
increases," said Smith. "Because of its simpler design, smaller batch size,
and shorter drying cycle, the LPD can be scaled up without the substantial
increases in the size and weight required for a desiccant dryer.
There are no drying hoppers or desiccant bends, and the blowers required
are much smaller. The massive hardware of a large-capacity desiccant dryer and
the size of the structural components required to support it make this
conventional equipment far more expensive than an equivalent LPD machine."
Unique Technology Is Key to Energy Savings, Speed of Drying, and Speed of Color Change
The LPD dryer
differs radically from conventional hot-air/desiccant dryers in two ways: 1)
instead of flowing hot, dry air over the pellets to slowly draw the moisture
out, the patented LPD dryer uses vacuum to reduce the boiling point of water,
quickly turn the 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 separate stations, making possible small batches while
in effect transforming a batch process into a continuous one that keeps pace
with the throughput of the plastics processing machine.
batch size and short drying cycle of the LPD dryer make it possible to shorten
Monday morning cold startups from several hours to less than an hour, adding
that much more to weekly production time. Also
increasing productivity is the three-station indexing system of the dryer, which
makes possible color and material changes on the fly, eliminating downtime.
Another source of cost savings is the
elimination of desiccant, which, in a conventional dryer, becomes saturated and
must be regenerated by a heating and cooling process so it will again be able to
absorb moisture. The energy used in
this process is lost to the ambient
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 systems, granulators, dryers, auger feeders, and related
equipment. 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.
Europe, a sales and service subsidiary that supports customers
throughout Europe, operates a distribution center in Tamworth, Staffordshire,
United Kingdom. Maguire Asia, based in Singapore, serves customers throughout
South Asia and the Pacific Rim. Visit the Maguire Products web site: www.maguire.com