Upward Substrate Coating System for Uniform Washcoat Distribution
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Solution Overview
Problem
Existing methods for coating catalytic converters with low viscosity solutions face challenges such as uneven distribution, equipment fouling, and inefficiencies in coating monolithic substrates, particularly due to difficulties in controlling the application of low viscosity materials and ensuring uniformity of catalytic material deposition.
Innovation Solution
A coating system and method that uses a receiving chamber with a fluid inlet positioned below the substrate to pump the coating solution upward through the substrate, allowing for precise control and recovery of excess solution, minimizing contact with equipment and personnel, and ensuring uniform coating distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a vacuum is used to suck up the solution into the cells, then the coating can be applied to the substrate, but the low viscosity material is difficult to evenly distribute and control, causing overshoot and equipment fouling
Solution Approach 1:
Instead of using vacuum suction to draw solution into the substrate (conventional approach), the patent applies positive pressure to force the solution into the substrate cells. This inversion of the pressure differential direction eliminates the harmful effects of vacuum-induced overshoot and equipment fouling while achieving uniform distribution through controlled pressure application
Solution Approach 2:
The patent changes the pressure parameter from negative (vacuum) to positive, and controls the pressure magnitude to be sufficient to force solution into cells but not excessive to cause fouling. This parameter optimization enables precise control of low viscosity material application while preventing equipment contamination
2Manufacturing precision
If vacuum suction is used to draw solution into the substrate, then coating can be applied, but the coating time is excessive and productivity is low
Solution Approach 1:
By inverting the pressure approach from vacuum suction to positive pressure forcing, the patent dramatically reduces coating time. The positive pressure method pushes the solution through the substrate more efficiently than vacuum suction can pull it in, achieving both uniform coating depth and high productivity
Solution Approach 2:
The patent implements continuous pressure application to force solution through the substrate, eliminating the intermittent and inefficient vacuum suction process. This continuous action maintains optimal flow conditions throughout the coating operation, reducing total coating time while ensuring uniform distribution
3Ease of operation
If low viscosity solution is used for coating, then the coating can be applied smoothly, but the solution drips out of the substrate and contacts equipment and personnel in undesirable manner
Solution Approach 1:
The patent inverts the pressure differential approach, using positive pressure to force solution into the substrate rather than vacuum suction. This prevents the dripping problem characteristic of low viscosity materials under vacuum, as the positive pressure maintains controlled flow through the substrate structure
Solution Approach 2:
The patent converts the potential harm of low viscosity material dripping into a benefit by using positive pressure to control the flow. The same low viscosity property that enables smooth coating application also allows the positive pressure system to efficiently push the material through the substrate without dripping, turning a problematic characteristic into an advantage
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 system effectively coats the substrate with a low viscosity solution, improving homogeneity and reducing coating time, while preventing equipment fouling and enhancing manufacturing efficiency by ensuring uniform catalytic material distribution and recovery of excess solution.
Implementation Method 1
pumping the low viscosity coating solution through a fluid inlet positioned below the receiving chamber at a pressure sufficient to cause the coating solution to enter the receiving chamber
Implementation Method 2
migrate upward through pores or channels present in the substrate
Implementation Method 3
allowing a non-coating portion of the low viscosity coating solution to drain from the substrate through the vessel valve
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
Described herein is a coating system configured for providing a washcoat onto a substrate. The coating system can be configured to pump a coating solution, particularly a low viscosity solution, into a coating vessel have the substrate positioned therein. The coating system further includes elements configured for removal of a non-coating portion of the coating solution from the substrate and recycling of the non-coating portion. Also described herein are methods for applying a washcoat to a substrate as well as multi-station coater systems.