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recovering small scraps. Edge trim plastic granulator for in-line recovery of edge
trims from foil and film production lines.
Pelletizers: To enhance processablity and handling, almost all plastic resins are
made into pellets. Consistent particle size is critical in the melting process because
different particle sizes don't melt at the same rate. Pelletizers are mostly used in
petrochemical plants, recycling plant and compounding lines. The chopped scrap
are melted and extruded in form of strands, cooled and then cut in to pellets which
can be conveniently used for further processing by any method. An average pellet is
about 1/8 inch in length and diameter. Different types of pelletizers available are
Water ring die-face, Water bath, Water slide strand and underwater die-face
pelletizers.
Densifiers or Agglomerators: Agglomerators are extensively used for
reprocessing plastics. Films and other light plastic materials available in scrap are
not dense to be feed through a compounding machine and pelletizer to be extruded
into pellets directly. Hence they are required to be processed through an
agglomerator. The agglomerator when feed with scrap and little water added to it,
with the help of its cris-crossed blades and high powered motor heats the material
and converts it from film to lumps. The lumps being dense can then be fed into
granulator to be chopped and then processed further. Agglomerators with
capacities ranging from 25 Kgs per hour to 120 kgs per hour are available.
Pulverizers: Pulverized material (powdered form) is used as starting material in
rotational moulding, in powder coating and for other applications. Pulverizers are
machines that reduce the size of materials through grinding and crushing to
medium, fine or ultra-fine size. A pulverizer can be used in with granulation system
to further reduce particles.
Compactors: Compactors are designed to compress waste materials and scrap
products for easier transportation, handling and better space efficiency. A large
chamber, an electric motor and a hydraulic or pneumatic press are the three main
components of a compactor. Example of compacting bulky and light weight PET
bottles into bales reducing the bulk volume of trash reduces the money and effort
required to transport and disposal.
Screen Changers: During processing the molten polymer needs to be filtered to
remove any contaminants present in the melt. This is usually carried out by means
of breaker plate and screen pack assembly placed in the path of the melt flow just
after the extruder barrel and before the die. A screen pack consist of several layers
of woven wire discs of varying mesh and is backed by a densely perforated steel
disc, a breaker plate to withstand the force exerted by the melt flow. In normal
working to change a clogged screen pack, the downstream equipment has to be
removed, the clogged screen replaced with a clean one and the line re-assembled.
Screen changers are mechanical devices that permit changing screens without
interrupting machine, saving cost involved in downtime and production loss.
Different types of screen changers are: Manual changers, Pneumatic changers,
Hydraulic changers and Continuous changers.
Hot oil units: Hot oils (also referred to as heat transfer fluids and thermal fluids) are
predominantly used for the following applications and purposes in plastics industry:
Used to heat the resin as it travels through Injection moulding machinery and mould

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