Coating Color Degassing via Oscillation
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Solution Overview
Problem
Existing degassing methods for coating colors, especially for highly viscous substances, are inefficient due to insufficient deaeration capacity, leading to unstable gas content in the coating material, which results in surface roughness and uncoated areas on fibrous webs, particularly in multilayer curtain coating processes.
Innovation Solution
A method involving a storage tank system where coating color is supplied to the degassing stage at a constant rate, with excess returned to the storage tank, and the degassed color is supplied to the coating device at a constant rate, using a two-stage vacuum degassing apparatus and on-line measuring equipment to maintain uniform gas content, ensuring stable degassing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vacuum degree is increased to improve deaeration capacity, then gas removal efficiency is improved, but solvent vaporisation increases causing solids content to increase
Solution Approach 1:
The patent applies preliminary action by using oscillation treatment before vacuum deaeration to pre-coalesce small gas bubbles into larger ones. This preliminary step makes the subsequent vacuum deaeration more effective at lower vacuum degrees, preventing solvent vaporisation while still achieving thorough gas removal. The oscillation frequency is typically 16-60 kHz, which causes bubbles to integrate and grow large enough to be easily removed.
Solution Approach 2:
The patent employs mechanical vibration through oscillation treatment at frequencies of 16-60 kHz to agitate the coating colour and cause gas bubbles to coalesce. This vibration mechanism transforms the distribution of gas bubbles from dispersed small bubbles to larger coalesced bubbles, dramatically improving deaeration capacity without requiring extreme vacuum conditions that would cause solvent vaporisation.
2Manufacturing precision
If processing time is increased to improve gas bubble removal, then deaeration quality is improved, but operational capacity decreases requiring more deaerators
Solution Approach 1:
The patent uses preliminary oscillation treatment to accelerate the gas bubble coalescence process, reducing the time required for effective deaeration. By pre-processing the coating colour to integrate bubbles before vacuum application, the system achieves high deaeration quality in shorter processing times, maintaining operational capacity without requiring additional deaerators.
Solution Approach 2:
The patent employs periodic oscillation action at specific frequencies (16-60 kHz) to continuously agitate the coating colour during the deaeration process. This periodic vibration maintains bubble coalescence throughout the processing time, ensuring thorough gas removal without extending the overall processing duration, thus preserving operational capacity.
3Productivity
If oscillation frequency is increased to improve gas bubble integration, then deaeration efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent optimizes the oscillation frequency parameter within the range of 16-60 kHz to achieve effective gas bubble coalescence. By carefully selecting and adjusting this parameter, the system achieves high deaeration efficiency without excessive energy consumption. The frequency is tuned to match the resonance characteristics of the bubbles and coating colour, maximizing effectiveness while minimizing energy use.
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 stabilizes the degassing process, producing coating colors with consistent gas content, reducing surface roughness and uncoated areas, and enhancing the operational efficiency of the coating process by maintaining uniform quality and capacity.
Implementation Method 1
various types of vacuum deaerators, a known embodiment of which comprises a rotating drum arranged inside a vacuum container
Implementation Method 2
oscillatory action is applied to the coating colour flow to be fed into the degassing apparatus, which causes the gas content to fall and/or the gas bubbles to integrate or their size to increase
Implementation Method 3
the coating colour rises up the inner wall of the drum by the effect of centrifugal force and is discharged from the drum as a thin film
Data Source
Figure 1
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AI summary
The invention relates to a method for processing and supplying coating colour used for coating a fibrous web to a coating device (5). In the method, the coating colour from coating colour production is delivered to a storage tank (1), from where it is taken to the degassing stage (2), and from there further to a supply tank (4) arranged in conjunction with the coating device (5).