Blown Film Cooling Gas Ring with Pre-Rotation Flow Guide
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Solution Overview
Problem
Existing cooling devices for blown films face issues with uneven cooling gas distribution, leading to thickness profile disturbances in the circumferential direction due to flow irregularities, which are often mitigated by increasing back pressure, resulting in higher energy consumption and temperature increases.
Innovation Solution
The implementation of a cooling device with a flow guiding device that sets a partial flow of cooling gas in rotation around a flow axis before it enters the ring channel, ensuring a uniform flow profile and reducing pressure loss, achieved through the use of at least one feed channel with a flow guiding device comprising fixed and adjustable guide elements that can be easily integrated into conventional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If downstream built-in components are added to reduce flow disturbance, then flow uniformity is improved, but air flow rate decreases and energy consumption increases
Solution Approach 1:
The flow guiding device is positioned upstream in the feed channel to pre-rotate the cooling gas before it enters the ring channel. This preliminary action creates a flow profile that reduces downstream flow disturbances, eliminating the need for downstream built-in components that would increase back pressure and energy consumption.
2Device complexity
If a single air feed connector is used, then device complexity is reduced, but flow uniformity deteriorates due to residual flow merging
Solution Approach 1:
The flow guiding device pre-rotates the cooling gas in the feed channel before it enters the ring channel. This preliminary rotation ensures that the single feed connector's output is uniformly distributed throughout the ring channel, preventing flow disturbances that would otherwise require multiple feed connectors to resolve.
3Manufacturing precision
If multiple air feed connectors are distributed circumferentially, then flow uniformity is improved, but device complexity and number of connecting hoses increase
Solution Approach 1:
The flow guiding device creates a rotating flow pattern in the single feed channel that uniformly distributes cooling gas throughout the ring channel circumference. This preliminary distribution action eliminates the need for multiple circumferentially distributed feed connectors and their associated connecting hoses, reducing device complexity while maintaining flow uniformity.
4Manufacturing precision
If residual flow is forced to circulate more than 360° through the ring channel, then flow distribution is improved, but pressure loss increases
Solution Approach 1:
The flow guiding device pre-rotates the cooling gas in the feed channel, creating an optimized flow profile before the gas enters the ring channel. This preliminary action reduces the resistance to flow in the ring channel, allowing residual flow to circulate with lower pressure loss while maintaining effective cooling gas distribution.
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
This solution ensures a uniform distribution of cooling gas across the circumference, reducing flow irregularities and maintaining low back pressure, thereby enhancing the thickness profile consistency and energy efficiency of the cooling process.
Implementation Method 1
at least one flow guiding device which is arranged and constructed such that at least a partial flow of a cooling gas flowing through the at least one feed channel into the ring channel is set in rotation about a flow axis
Data Source
AI summary
A cooling device for external cooling of a film tube subjected to internal pressure in the production of blown films of thermoplastic material includes a cooling gas ring with a ring housing and a ring nozzle arranged concentrically to a central axis and being open towards the film tube. At least one inner ring channel extending in the circumferential direction about the central axis and being open radially inwards towards the ring nozzle is included. At least one feed channel for supplying cooling gas is attached to the ring housing and connected to the ring channel. The cooling device also includes at least one flow guiding device arranged in the at least one feed channel. When a cooling gas flows through the flow guiding device, at least a partial flow of the cooling gas is set in rotation about a flow axis prior to flowing into the ring channel.