Thermoplastic Pelletizer Pressure Control for Uniform Shape
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Solution Overview
Problem
Existing methods for producing thermoplastic resin pellets often result in irregular shapes, leading to industrial waste, equipment wear, and inefficiencies in pelletization processes, particularly with high elastic modulus polymers like polyamide MXD6, which complicates pneumatic transportation and increases disposal costs.
Innovation Solution
A process and apparatus that control the inner pressure of a batch-type polymerization vessel based on pressure differences during pellet transfer, ensuring a consistent resin discharge rate and uniform pellet formation through pneumatic or suction transportation, using inert gas or steam for pressurization and precise control of melt viscosity within specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the amount of molten polymer supplied to the pelletization apparatus is varied due to change in viscosity or extrusion pressure, then the pelletization process becomes unstable, but controlling the supply amount precisely requires complex pressure regulation systems
Solution Approach 1:
The patent employs a feedback control system where the pressure inside the polymerization vessel is monitored and adjusted based on the actual amount of molten polymer supplied to the pelletization apparatus. The pressure regulation means modifies the internal pressure in response to supply variations, creating a closed-loop control that automatically maintains stable pelletization conditions without requiring complex external regulation systems.
Solution Approach 2:
The polymerization vessel's internal pressure system serves dual purposes: it drives the polymerization reaction and simultaneously controls the supply of molten polymer to the pelletization apparatus. By utilizing the existing pressure mechanism for both reaction maintenance and supply control, the system avoids adding separate complex pressure regulation equipment while achieving precise control of polymer supply.
2Manufacturing precision
If vibration sieve is used to separate irregular-shaped pellets, then pellet quality improves, but production yield decreases due to removal of separated pellets
Solution Approach 1:
The patent prevents the formation of irregular-shaped pellets in the first place by controlling the supply amount of molten polymer to the pelletization apparatus. By regulating the internal pressure of the polymerization vessel to maintain stable extrusion conditions, the system avoids generating defective pellets that would otherwise require separation, thereby eliminating the need for vibration sieves and preserving production yield.
Solution Approach 2:
The pressure control system performs preliminary regulation of the polymer supply before pelletization occurs. By adjusting the internal pressure in advance to ensure consistent molten polymer flow, the system pre-prevents the formation of irregular pellets, making subsequent separation processes unnecessary and maintaining high production yield.
3Strength
If high elastic modulus polymer like polyamide MXD6 is processed, then material strength is improved, but equipment wear increases and pneumatic transportation becomes difficult
Solution Approach 1:
The patent controls the physical parameters of the molten polymer during extrusion by regulating the internal pressure of the polymerization vessel. By maintaining optimal pressure and flow conditions, the system ensures that high elastic modulus polymers like polyamide MXD6 are extruded at controlled rates, preventing excessive hardness that would cause equipment wear and pneumatic transportation difficulties while preserving the material's inherent strength properties.
Data Source
AI summary
The present invention provides an apparatus for producing thermoplastic resin pellets of uniform shape. The apparatus includes a batch-type polymerization vessel whose inner pressure can be controlled; a pelletizer for cutting a strand-form thermoplastic resin discharged from the polymerization vessel, thereby forming pellets; a pipe for transferring the pellets to a storage container by pneumatic transportation or suction transportation; a pressure differential measuring unit for determining variation in a pressure difference between the inlet and the outlet of the transfer pipe; and a pressure controlling unit for controlling the inner pressure of the batch-type polymerization vessel on the basis of the variation in the measured pressure difference; wherein the inner pressure of the batch-type polymerization vessel is controlled in relation to a pressure loss in the transfer pipe.