Blown Film Cooling Element With Angled Airflow for Tube Stability
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Solution Overview
Problem
Existing thermoplastic blown film cooling systems face limitations in throughput rate, stability, and noise levels due to excessive holding forces, turbulence, and the need for complex control systems, particularly in internal cooling systems.
Innovation Solution
A divergent cooling system with angled air foil surfaces and a cooling gas deflector that directs cooling gas in opposite directions to create suction forces, stabilizing the molten film tube and minimizing mechanical contact, combined with unidirectional cooling elements that utilize compound angles to enhance throughput and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external cooling systems apply cooling gas to flow along the surface of the molten film tube to create holding forces, then cooling effectiveness is improved, but excessive holding forces cause vibration, flutter, and high noise levels
Solution Approach 1:
The patent changes the parameters of the cooling gas flow by introducing angled air foil surfaces that direct cooling gas at specific angles (e.g., 10-45 degrees) relative to the molten film tube surface. This angular parameter modification allows the cooling gas to provide cooling effectiveness while reducing excessive holding forces that cause vibration and noise.
Solution Approach 2:
Instead of applying cooling gas directly along the surface to maximize holding forces, the patent inverts the approach by using angled surfaces to direct cooling gas in a way that creates suction forces rather than excessive holding forces. This inversion resolves the contradiction between cooling effectiveness and vibration reduction.
2Productivity
If cooling elements are extended upward to increase cooled surface area and throughput, then throughput rate is improved, but greater unsupported surface area leads to degraded stability
Solution Approach 1:
The patent modifies the geometric parameters of the cooling element by introducing angled air foil surfaces and optimizing the spacing between cooling elements. These parameter changes allow for extended upward configuration to increase throughput while the specific angular and spacing parameters maintain film tube stability by reducing excessive holding forces.
3Productivity
If internal cooling systems are used to generate additional throughput, then throughput rate is improved, but complex control systems are required to balance internal exhaust gas flow
Solution Approach 1:
The patent extracts the complex control system requirement from the internal cooling approach and replaces it with an external cooling system using angled air foil surfaces. This extraction eliminates the need for complex feedback control while maintaining throughput improvement through aerodynamic design.
4Temperature
If cooling gas is applied against the surface to create turbulent cooling with repelling forces, then cooling effectiveness is improved, but a separate means is required to stabilize the molten film tube
Solution Approach 1:
The patent merges the cooling function and stabilization function into a single integrated system. The angled air foil surfaces simultaneously provide cooling effectiveness and create suction forces that stabilize the molten film tube, eliminating the need for separate stabilization means.
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 increased throughput rates, improved aerodynamic holding forces, reduced vibration and flutter, lower sound power levels, and simplified control, while maintaining film quality and stability.
Implementation Method 1
directs cooling gas to flow in opposite directions, creating suction forces. These suction forces hold and stabilize the molten film tube
Implementation Method 2
cooling gas to flow in opposite directions... directs cooling gas to flow along the air foil surfaces
Data Source
AI summary
The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process. Embodiments of the present disclosure provide a unidirectional cooling element having a unidirectional cooling interface containing a cooling gas deflector spaced adjacent to the molten film tube. The unidirectional cooling element operably expels cooling gas in a path with the flow of the molten film tube toward an exit gap formed between the unidirectional cooling interface and the molten film tube. The minimum gap between the unidirectional cooling interface and the molten film tube occurs at the exit gap, and advantageously, the unidirectional cooling interface is provided with one or more compound angles to maximize stability and cooling efficiency.