Application:
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Weight Based Blending of Plastic Pellets
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Industry:
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Thin Film Production/Plastics Extrusion Process
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Products:
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25F Momentum Feeder
Blendview Management and Control System
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Process Description
Plastic pellets of various components
are blended together in specific proportions prior to entering the melting and
forming process. The exact
composition of this blend is critical in the final product composition and
quality.
Plastic pellet blending is
accomplished using two methods. One
method is to meter individual components into a receiving hopper known as batch
blending. The receiving hopper is
often mounted on a load cell systems and each component is metered sequentially
in to the hopper to a preset target weight to prepare the batch for processing.
Alternately volumetric devices can be
used to feed all of the compounds at the same time. The compounds are mixed as they enter the receiving hopper during the
transport phase. Volumetric feeding
can be timed to estimate the weight of the batch or can be fed in to a receiving
hopper on load cells.
Consistency in the composition of the
batch is a key element in quality control of the final product. The ideal solution to this process would be to use a continuous
weight-based feeding device to precisely blend the mixture in to the
melting and forming process.
Comptrol's 25F Momentum Feeder is
capable of delivering a controlled flow of material from a bin or silo at an
accuracy of-/+ 0.5% of full scale over a wide operating range. When connected to Comptrol's Blendview system, a number of the 25F Momentum Feeders can blend to a specific
recipe the final product straight to the forming process. This will produce a consistent blend based on precise weights and improve
the final product's consistency and quality.
Advantages
of Weight Based Blending with 25F Momentum Feeders
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Weight-based blending significantly improves the quality
of the final product composition. It
produces a blended product with the correct composition of raw material by
weight. This is a key driving
quality issue for weight based blending.
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Repeatability achieved using weight-based technology versus
volumetric technology produces better final product consistency.
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In applications were one of the components is significantly
more expensive, weight based blending ensure that there is no excessive
waste of expensive materials.
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High throughput processes are requiring continuous inline
blending to meet production rates that are not achievable economically using
batch blending approach.
Features Critical to Application.
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25F Momentum Feeder can be installed beneath silo or bins with as little as 18
inches (460 mm) of head room.
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25F Momentum Feeders can directly feed a mixing or transport conveyor with the
precise weight based blend.
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25F Momentum Feeders can be installed in unheated environments since they do not require compressed air for operation.
Competitive
Advantages
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Cost comparable to variable speed volumetric device but
with strength of weight based feeding.
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Less expensive than loss in weight feeding technology but
with similar results.
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Feeders have a 10:1 turn down ratio.
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A number of models are available from 4 tones through to 80
tones allowing a wide range of feed rates from a minimum of 800 lb/hr to a
maximum of 160,000 lb/hr.
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The feeders can be interface to a PLC application for
control of recipe blending directly through standard I/O or to a SCADA
system using a DDE link.
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Feeder can be installed with a Blendview system as a stand-alone blending system. Blendview is capable of storing, controlling, tracking and reporting blends produced. In addition, it monitors the current operation providing the operator
with live feedback on the blending operation.
Target
Customer
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Stretch Film/Thin Film Producers
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Plastic Extrusion Companies
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