Curtain Coater Labyrinth Flow Path for Uniform Film
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Solution Overview
Problem
Existing curtain applicators face challenges in achieving uniform distribution of coating material over large web widths and varying viscosity conditions, leading to streaks and coating defects due to the need for additional actuators and difficulty in combining partial flows into a uniform film flow.
Innovation Solution
A curtain applicator design featuring a labyrinthine flow path with alternating throttle points and expansion chambers to combine section flows into a uniform film flow, ensuring even pressure and quantity distribution across the transverse direction, preventing streaks and enhancing coating uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional actuators and multiple distribution chambers are used to equalize pressure and quantity distribution, then coating uniformity is improved, but device complexity increases
Solution Approach 1:
The application medium is divided into section flows that are processed through individual flow channels with specific flow path patterns, allowing localized control and equalization without requiring complex actuators in each section
Solution Approach 2:
Labyrinthine flow path patterns are implemented in the flow channels to create tortuous paths that naturally equalize pressure and quantity distribution across different sections, eliminating the need for additional actuators while maintaining coating uniformity
2Device complexity
If section flows are combined in a simple manner, then device complexity is reduced, but streaks and coating defects occur due to inability to form uniform film flow
Solution Approach 1:
Labyrinthine flow path patterns are used to create complex tortuous paths that naturally mix and equalize section flows, enabling uniform film flow formation without requiring complex actuation systems
Solution Approach 2:
The flow channels with labyrinthine patterns act as intermediaries that transform individual section flows into a unified, uniform film flow by creating extended contact and mixing paths
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 effectively combines section flows into a uniform film flow, eliminating streaks and ensuring consistent coating thickness across the web width, even under fluctuating conditions, thereby improving production efficiency.
Implementation Method 1
a flow path with several changes in direction, which runs through throttle points and expansion chambers
Implementation Method 2
The flow path patterns are labyrinthine flow path patterns
Data Source
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AI summary
The curtain coater has a nozzle portion which is provided with a primary distributor chamber (1). A flow channel (2) is provided to break up the application medium into sectional flows. A secondary distributor chamber (3) is provided to discharge the application medium through an outlet slot (4). The different directional flow path is formed in the secondary distributor chamber. The flow direction runs through throttling points and expansion chambers.