Process for treating polymer granular material and plant operating according to such a process
AssigneePegaso Industries S.P.A.
InventorRinaldo PIVA
Life of this patent
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Abstract
A process for treating polymer granular material (2) comprising the steps of heating and drying the polymer granular material in a drying hopper (10) by means of a drying gas, discharging a portion of the polymer granular material into an extruder (101), inside which the polymer granular material is brought to a molten or semi-molten state and transported along the extruder by a rotating screw (104) in order to be injected into a mould (102) or caused to pass through an extrusion head. The process provides for measuring a control parameter which is correlated with the rotation of the screw inside the extruder and regulating the flow rate of the drying gas on the basis of the control parameter.
Claims10
A process for treating polymer granular material (2) comprising:
- providing the polymer granular material in a drying hopper (10),
- introducing into the drying hopper a drying gas having a predefined flow rate and temperature so as to heat the polymer granular material up to a discharge temperature and to dry the polymer granular material up to a predefined residual humidity value,
- discharging a portion of the polymer granular material which is heated to the discharge temperature into a transformation unit (100) for the polymer material, in which the transformation unit comprises an extruder (101), inside which the polymer granular material which is discharged from the hopper is brought to a molten or semi-molten state and transported along the extruder by a rotating screw (104) in order to be injected into a mold (102) or caused to pass through an extrusion head,
- measuring a control parameter which is correlated with the rotation of the screw inside the extruder and
- regulating the flow rate of the drying gas on the basis of said control parameter.
The processing installation (1) for polymer granular material (2) comprising:
- at least one drying hopper (10), comprising an inlet (11) for the polymer granular material and an outlet (12) for the polymer granular material which is connected to a transformation unit (100) for the polymer granular material,
- a heating circuit (20), by means of which a drying gas is introduced into the drying hopper in order to heat the polymer granular material up to a discharge temperature and to dry the polymer granular material up to a predefined residual humidity value,
- a regulation device (25) for regulating the flow rate of the drying gas,
- a transformation unit which is positioned downstream of the drying hopper and which comprises an extruder (101), inside which the polymer granular material which is discharged from the drying hopper is brought to a molten or semi-molten state and transported along the extruder by a rotating screw (104) in order to be injected into a mold (102) or caused to pass through an extrusion head of the transformation unit,
- a main sensor (110) which is provided to measure a control parameter of the transformation unit which is correlated with the rotation of the screw (104) inside the extruder,
- a control unit (30) which is connected at least to the first sensor (110) and the regulation device (25) of the flow rate of the drying gas and which is provided to control the regulation device (25) of the flow rate of drying gas in accordance with the value of the control parameter which is measured by the first sensor (110).
Dependencies are inferred from the claim text.