Cold pelleting system: a cold pelleting system consists of a die, a cooling zone (air cooled or water cooled), a drying zone (if water cooled) and a pelleting chamber. There are two kinds of cold granulation systems, that is, sheet granulator and strip granulator.
The molten polymer is extruded from the hot die and cut into pellets by a rotary knife that rotates on the surface of the die. The glue-granulating system features a specially designed water-jet granulating chamber. Water flows in a spiral until it flows out of the granule chamber. After the pellets are cut, they are thrown into the current for preliminary quenching. The granular water slurry is discharged into the granular slurry tank where it is further cooled and then fed into a centrifugal dryer to remove moisture.
The use history of strip granulator is almost as long as that of sheet granulator. Includes mouth die, cooling section (water bath or blower), drying section (if water cooling is used), and granulating knife. The molten polymer is extruded by an extruder or a gear pump through a horizontal mounting die to form a bar (modern die is precision machined and uniformly heated to produce a stable quality bar). After the strip is discharged from the mouth, it is cooled by a blower or an air/vacuum device, or by a water bath. If water cooling is used, the strips shall pass through a dry section, remove moisture with forced ventilation, and then be sent to the pelletizing chamber. Using the shear action of a pair of fixed knives and a rotating knife, the bar is cut to the desired length precisely.
