Evaporative Cooling for Plastic Extrusion Profiles
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Solution Overview
Problem
Existing methods for increasing the cooling capacity of extrusion lines for plastic profiles are inefficient in terms of cost and result in uneven cooling, with liquid often running down the profile circumference and heat not being evenly distributed across the cross-section.
Innovation Solution
The method involves increasing the temperature and saturation of a gaseous medium by adding a liquid medium via spray nozzles, ensuring efficient heat transfer without exceeding the dew point, and adjusting air and water amounts using a mathematical model to optimize heat dissipation, while also recycling condensed water and using baffles to direct airflow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid medium is sprayed for cooling the profile, then cooling capacity is increased, but liquid runs down along the profile circumference causing uneven cooling
Solution Approach 1:
The patent utilizes the phase transition of water from liquid to vapor through evaporative cooling. Water is sprayed as liquid onto the profile surface, where it evaporates and absorbs heat, providing efficient cooling without the liquid running down the profile. This phase change mechanism allows for high cooling capacity while maintaining uniform cooling distribution.
Solution Approach 2:
The patent introduces a gaseous medium (air) as an intermediary carrier that transports the evaporated water vapor away from the profile surface. This intermediary gas flow prevents liquid accumulation and ensures uniform cooling by continuously removing heat and moisture from the profile surface, eliminating the problem of liquid running down the circumference.
2Temperature
If cooling medium is directed at high velocity to occur turbulent flow, then heat dissipation is improved, but energy consumption increases
Solution Approach 1:
The patent employs evaporative phase transition of water to achieve efficient heat dissipation without requiring high-velocity turbulent flow. The latent heat of vaporization provides intensive cooling at the profile surface, while the surrounding air naturally convects the vapor away, achieving effective heat removal with minimal energy input compared to forced turbulent flow systems.
Solution Approach 2:
The cooling system utilizes natural convection currents of the surrounding air to remove evaporated water vapor from the profile surface. This self-service mechanism eliminates the need for high-velocity forced flow or complex turbulent flow generation systems, reducing energy consumption while maintaining effective heat dissipation through the evaporative cooling process.
3Productivity
If saturation of gaseous medium is increased for better cooling, then dew point is approached, but condensation occurs causing quality defects
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the saturation level of the gaseous cooling medium and adjusts the water spray rate accordingly. When the dew point approaches, the system automatically reduces water input to prevent condensation, ensuring optimal cooling efficiency while maintaining profile quality by avoiding excessive saturation that would cause condensation defects.
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 approach enhances cooling efficiency, prevents heat from being withdrawn in the extrusion direction, reducing the risk of tensions and quality defects, and allows for even cooling across the profile cross-section without excessive energy consumption.
Implementation Method 1
Heat is transferred from the profile to the air via its surface
Implementation Method 2
A liquid medium is added between the inlet area and the outlet area via spray nozzles, the liquid medium evaporates by heating
Implementation Method 3
the liquid medium evaporates by heating and the saturation of the gaseous medium is increased
Implementation Method 4
calibrating and curing by cooling the profile in a cooling and/or calibrating unit
Data Source
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AI summary
The invention relates to a method for increasing the cooling power of an extrusion line and for extruding a plastic profile in an energy-efficient manner, in particular a plastic tube, having the following steps: a) melting plastic in an extruder (1), b) shaping a plastic strand and feeding the plastic strand to a tool (2), c) shaping a plastic profile using the tool (2), and d) calibrating and curing the profile by cooling the profile in a cooling and/or calibrating process (3), wherein a gaseous medium is suctioned through one or more cooling tanks (7, 8, 9) in order to cool the exterior of the profile (6). According to the invention, the temperature and the saturation of the gaseous medium is increased between an inlet region (19) and an outlet region (20) for the gaseous medium, and a liquid medium is added between the inlet region (19) and the outlet region (20) via spray nozzles (22), said liquid medium being evaporated by a heating process and the saturation of the gaseous medium being increased. The invention further relates to a device related to the method.