Coating Apparatus Flexible Membrane Diffuser Honeycomb Monolith
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Solution Overview
Problem
Existing coating techniques for honeycomb monoliths in automotive exhaust catalysts face challenges in evenly distributing liquid coating slurry on the top end face, leading to uneven washcoat distribution within the channels, which affects the catalytic activity and efficiency of pollutant abatement.
Innovation Solution
A substrate coating apparatus with a flexible perforated membrane diffuser and a pressure difference application unit ensures even distribution of the liquid coating slurry on the top end face of the monolith, allowing it to be evenly pulled into the channels without additional measures, and optionally applying a second coating from the bottom without moving the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid coating slurry is applied to the top end face of the monolith, then the substrate can be coated with washcoat, but the slurry distribution becomes uneven leading to uneven washcoat distribution within channels
Solution Approach 1:
The patent employs a flexible membrane as a diffuser barrier that distributes liquid coating slurry uniformly across the top end face of the monolith. The membrane's flexibility allows it to conform to the substrate surface while its porous structure enables even slurry distribution, preventing the uneven coating problem associated with direct top-down application methods.
Solution Approach 2:
The diffuser barrier acts as an intermediary component between the slurry application system and the monolith substrate. This intermediate element mediates the slurry delivery process by distributing the liquid evenly across the top end face before it penetrates into the channels, thereby achieving uniform washcoat distribution without requiring substrate rotation or complex nozzle systems.
2Manufacturing precision
If additional measures like rotating the substrate are taken to achieve even slurry distribution, then coating uniformity improves, but device complexity and operational difficulty increase
Solution Approach 1:
The patent extracts the complexity of achieving uniform coating distribution from the substrate handling system and transfers it to a stationary diffuser barrier component. By removing the need for substrate rotation or complex nozzle movement mechanisms, the solution simplifies the overall device while maintaining coating uniformity through the diffuser's inherent distribution capability.
Solution Approach 2:
The diffuser barrier performs the function of uniform slurry distribution passively through its structural design, without requiring active substrate manipulation. The barrier's porous structure and flexibility enable it to self-regulate slurry flow distribution across the monolith surface, eliminating the need for external mechanical interventions like rotation or complex positioning systems.
3Manufacturing precision
If pressure difference is applied to pull slurry into channels, then coating penetration is achieved, but slurry may not distribute evenly without preliminary even application
Solution Approach 1:
The patent implements preliminary even distribution of liquid coating slurry across the top end face of the monolith using the diffuser barrier before applying pressure to drive penetration into channels. This preliminary uniform distribution ensures that when pressure is subsequently applied, the washcoat penetrates evenly throughout the channel structure, achieving uniform coating without requiring complex pressure control or multiple application passes.
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 method achieves uniform coating distribution and increased catalytic activity by ensuring even application and penetration of the washcoat into the substrate channels, enhancing pollutant abatement efficiency while being economical and ecologically advantageous.
Implementation Method 1
a diffusor in the form of a flexible perforated membrane, through which the liquid coating slurry is applied to an area of the top end face of the support body - preferably solely - when applying a pressure to the liquid coating slurry
Implementation Method 2
a unit for applying a pressure difference versus the support body, i.e. by applying a vacuum and/or a pressure to at least one end face of the support body
Data Source
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AI summary
The present invention is directed to an apparatus and a respective process, which can be used in the production of exhaust catalysts. In particular, the present apparatus is used in a process to supply the liquid coating slurry to substrates, like honeycomb monoliths.