Vacuum Sizing Tank with Electro-Mechanical Flow Control
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Solution Overview
Problem
Current extrusion processes face challenges in precisely controlling water and vacuum flows, leading to unwanted deformation of molten extrudate due to unpredictable forces and temperature variations, especially in the production of small diameter and thin wall tubing, which is critical for industries like medical devices.
Innovation Solution
A vacuum sizing tank system equipped with water pumps, manifolds, valves, sensors, and controllers to manage water and vacuum flows, ensuring uniform and controlled conditions, with modular features to adjust flow rates and pressures, and temperature zones to minimize deformation and achieve precise extrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual valve adjustment is used to control water flow, then the system is simple to operate, but the flow control precision is poor and uniformity along the extrudate length is not achieved
Solution Approach 1:
The water flow control system is segmented into multiple independent zones along the extrusion line, with individually controllable valves at different positions. This allows precise control of water flow at each segment, achieving uniform cooling along the entire extrudate length while maintaining manageable system complexity through modular valve placement.
Solution Approach 2:
The system transitions from static manual valve adjustment to dynamic automated control where valve positions and opening degrees are continuously adjusted based on real-time feedback from flow sensors and temperature sensors. This dynamic control enables precise flow regulation that adapts to changing process conditions, significantly improving manufacturing precision.
2Temperature
If water flow is increased to improve cooling, then cooling efficiency improves, but unwanted currents and eddies increase causing extrudate deformation
Solution Approach 1:
The water flow system is designed with different flow rates and temperatures at different positions along the extrusion line. The first water flow applied to the initial cooling zone has different characteristics than subsequent flows, with each zone optimized for its specific cooling requirements. This local differentiation achieves effective cooling while minimizing disruptive currents and eddies that cause deformation.
Solution Approach 2:
The system applies water flow in a controlled periodic sequence rather than as a single continuous stream. Multiple water flows are applied at different times and positions along the extrusion line, allowing each pulse of water to cool the extrudate gradually without creating excessive currents. This periodic application pattern maintains cooling efficiency while preserving extrudate shape stability.
3Shape
If vacuum is applied to prevent hollow extrudate from floating, then extrudate positioning improves, but additional complex equipment is required
Solution Approach 1:
The vacuum system is merged with the existing water flow control system, where vacuum is applied through the same tank structure that contains the water flows. The vacuum lines are integrated into the tank walls, allowing simultaneous application of water cooling and vacuum positioning without requiring separate equipment. This merging approach improves extrudate positioning while minimizing additional equipment complexity.
4Manufacturing precision
If temperature variations are allowed in water flow, then energy consumption decreases, but extrusion precision and dimensional stability deteriorate
Solution Approach 1:
The system carefully controls and maintains water temperature parameters within narrow ranges for each cooling zone. Temperature sensors monitor water temperature at multiple positions, and the system adjusts water flow rates and timing to compensate for thermal variations. This parameter control ensures dimensional stability of the extrudate while managing energy consumption through efficient heat transfer and minimized water volume requirements.
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 system achieves enhanced precision in extrusion by maintaining consistent water and vacuum flows, reducing deformation, and allowing for the production of small profiles with tight tolerances, as demonstrated by improved tolerances in test results compared to existing methods.
Implementation Method 1
The vacuum sizing tank may comprise an enclosed trough capable of holding water, holding a plurality of vacuum and a plurality of different water flows
Implementation Method 2
The water pump applies pressure to the various manifolds, which direct the water into and through the tank in a controlled fashion
Implementation Method 3
Upon immediately exiting the extruder, the plastic may remain in the molten state. In this state, the molten plastic is easily susceptible to deformation up until it is sufficiently cooled to a solid state
Data Source
AI summary
A vacuum sizing tank configured to provide controlled fluid flow. A fluid control system and a vacuum sizing tank utilizing electronic controls to create and maintain controllable fluid flow within the tank. Flow meters may measure the flow in and out of the tank to maintain consistency. Temperature meters may measure the temperatures for each of the flows to maintain consistency. An electronic circuit may compare the values with preset values. Any difference between the values may trigger change by varying the voltage applied to a variable speed water pump.