Online Polymer Viscosity Measurement via Diverted Batch Flushing
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Solution Overview
Problem
Existing online viscosity measurement systems for polymers are limited by impurities and lack long-term durability, especially in polyolefin recycling, where contamination levels are high, and current methods often require offline laboratory evaluations.
Innovation Solution
A device and method for online viscosity determination involve diverting polymer batches to a measurement module, where a specified volume is expelled through a measuring nozzle under pressure, with the time measured to calculate viscosity, and the system is designed for continuous operation with flushing to prevent contamination and ensure accurate, long-term measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If small melting pumps with clearances of 20 μm are used for online viscosity measurement, then measurement precision is improved, but reliability deteriorates due to contamination from 100 μm to 1000 μm in polyolefin recycling
Solution Approach 1:
The invention extracts the measurement function from the main processing stream by diverting batches of polymer to a separate measurement module. This allows the measurement system to operate with clean, diverted material rather than being exposed to the full contamination load of the recycling stream, thereby maintaining both precision and reliability
Solution Approach 2:
The invention introduces an intermediary flushing mechanism that uses a portion of the polymer itself to clean the measurement volume between measurements. This intermediary action removes contaminants without requiring external cleaning agents or shutting down the system, maintaining measurement reliability in contaminated environments
2Measurement precision
If offline laboratory evaluation methods are used for viscosity determination, then measurement precision is improved, but productivity deteriorates due to time-consuming processes
Solution Approach 1:
The invention replaces complex offline laboratory measurement systems with a simplified online measurement module that uses basic pressure application and timing. This substitution maintains sufficient measurement precision while enabling continuous operation during polymer processing, dramatically improving productivity
Solution Approach 2:
The invention enables continuous viscosity measurement by integrating the measurement module into the ongoing polymer processing stream. Measurements are taken continuously as batches pass through, eliminating the interruption and time loss associated with offline laboratory analysis
3Productivity
If the measurement volume is continuously exposed to polymer flow, then productivity is improved, but measurement precision deteriorates due to deposits and residues affecting measurements
Solution Approach 1:
The invention implements periodic flushing of the measurement volume using a blocking module that diverts polymer flow through the measurement volume at predetermined intervals. This periodic cleaning action removes deposits and residues that would otherwise degrade measurement precision, while allowing continuous operation between flushes
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
The solution enables reliable, continuous online viscosity measurement without interrupting polymer processing, providing accurate and durable results even in contaminated environments, allowing for real-time control of the processing procedure and segregation of polymers based on viscosity.
Implementation Method 1
a specified volume of the respective batch is expelled from the measurement volume by subjecting the batch to a predetermined pressure through a measuring nozzle formed in the measuring module, optionally via a piston to which a predetermined force, preferably a constant force, is applied
Implementation Method 2
the time required for expelling the specified volume of the batch through the measuring nozzle is measured
Implementation Method 3
these measured values determined are used for calculating the viscosity of the polymer
Data Source
AI summary
A method and a device for the online determination of the viscosity of a polymer in pasty to liquid form undergoing processing, such as extrusion is disclosed. It is provided that for the online determination of the viscosity of the polymer, at least a portion of the polymer undergoing processing is diverted and conveyed to the measurement volume of a measuring module, a predetermined volume of the respective batch is expelled from the measurement volume through a measurement nozzle by subjecting the batch to a predetermined pressure, the time required for expelling the predetermined volume of the batch is measured, the measured values are used for calculating the viscosity of the polymer, and prior to the filling of the measurement volume with the polymer to be measured, the measurement volume is flushed at least once with a quantity of the polymer being processed.