Plastic Processing Pressure Control Based on Residual Humidity

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Solution Overview

Problem

Existing plastic processing plants face challenges in setting accurate set point values for molten state pressures, leading to inefficiencies, increased production waste, and energy consumption due to manual adjustments based on historical data and manufacturer guidelines.

Innovation Solution

A method and apparatus that control molten plastic pressures using real-time humidity measurements from dehumidified solid plastics, adjusting set point values based on residual humidity to optimize processing conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual adjustment of pressure set point values is performed based on historical data and manufacturer guidelines, then initial pressure settings can be established, but the process requires long refinement time, increases production waste, and raises energy consumption

Engineering Contradiction:
Improvepressure set point accuracyVSAvoidrefinement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements a feedback control system where the actual injection pressure is continuously measured and compared with the set point value. The controller automatically adjusts the pressure set point based on the difference between actual and target pressure, eliminating manual trial-and-error refinement and significantly reducing adjustment time while maintaining precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical adjustment of pressure settings with an automated electronic control system. The controller receives pressure signals from sensors and automatically modifies set point values, substituting human operator intervention with an automated feedback mechanism that operates continuously without time loss.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If manual adjustment of pressure set point values is performed based on historical data and manufacturer guidelines, then initial pressure settings can be established, but production waste and energy consumption increase due to prolonged refinement processes

Engineering Contradiction:
Improvepressure set point accuracyVSAvoidproduction waste
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The feedback control system continuously monitors injection pressure and automatically adjusts set point values to maintain optimal processing conditions. This prevents prolonged operation with suboptimal settings that would cause defective parts and material waste, ensuring precise pressure control from the start of production.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system performs self-adjustment of pressure set points based on real-time feedback without requiring external manual intervention. The controller automatically optimizes processing parameters, preventing production waste by maintaining correct pressure settings continuously without human error or delay.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If manual adjustment of pressure set point values is performed based on historical data and manufacturer guidelines, then initial pressure settings can be established, but process stability decreases due to operator dependency and lengthy adjustment periods

Engineering Contradiction:
Improvepressure set point accuracyVSAvoidprocess stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The feedback control system continuously monitors injection pressure and automatically adjusts set point values to maintain optimal processing conditions. This eliminates variability introduced by manual adjustment and ensures consistent, stable pressure control throughout the production process, reducing dependency on operator skill and experience.

Inventive Principle:
Principle #23Feedback

4Productivity

If real-time humidity measurement and pressure control is implemented, then rapid and reliable pressure optimization is achieved, but device complexity increases due to additional sensor means and control logic

Engineering Contradiction:
Improvepressure optimization speedVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control system integrates multiple functions into a single controller unit that handles both humidity measurement and pressure control. The controller receives signals from both the humidity sensor and pressure sensor, and automatically adjusts pressure set points based on humidity conditions, combining multiple control functions in one device to minimize additional complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The controller acts as an intermediary that receives input from the humidity sensor and translates it into appropriate pressure set point adjustments. This intermediary component simplifies the overall system architecture by providing a centralized control point that coordinates between different sensors and actuators without requiring complex direct connections between all components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables rapid, reliable, and efficient control of molten plastic pressures, reducing waste and energy consumption while improving process stability and efficiency.

Implementation Method 1

sensor means that determines in real time a value of residual humidity of the incoherent solid plastics exiting dehumidifying and/or drying means

Methodology Applied
Scientific EffectHumidity measurement: Hygrometer

Implementation Method 2

dehumidifying and/or drying means connected in fluid communication with the means for performing moulding

Methodology Applied
Scientific EffectDehumidification: Desiccation

Implementation Method 3

means for melting the dehumidified and/or dried solid material

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 4

means for melting the dehumidified and/or dried solid material

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 5

controlling a pressure of the plastics in molten state... a set point value for controlling the pressure of the molten material is set on the basis of a measured humidity value

Methodology Applied
Scientific EffectPressure control: Pressure Gradient

Data Source

PatentEP3928045B1Method and apparatus for processing plastics
Publication Date: 2025.10.08 PIOVAN
  • EP3928045B1 patent drawingFigure 1

AI summary

A method and an apparatus are disclosed for processing plastics, in which the material in incoherent solid state is dehumidified in a hopper and is then melted in an extruder, after which the molten material is used in a moulding device for moulding by injection and/or by blow moulding and/or compression, and in which a set point pressure value of the molten material is set on the basis of a measured residual humidity value of the dehumidified incoherent solid material, so as to decrease the pressure value by a preset variation value if the measured residual humidity value is lower than a reference value and to increase the pressure value by a preset variation value if the measured residual humidity value is higher than said reference value.