Washcoat Showerhead Suction Control for Uniform Substrate Coating
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Solution Overview
Problem
Existing methods for coating substrates used in exhaust gas purification face issues such as uneven washcoat profiles, washcoat dripping or leakage, and increased back pressure due to multiple coatings, leading to operational inefficiencies and visual degradation.
Innovation Solution
A substrate coating apparatus and method utilizing a valve assembly with a movable outlet valve that creates a pressure drop within the washcoat showerhead, preventing dripping and leakage by generating a suction force, combined with a baffle layer and tubular inserts to direct washcoat evenly across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If washcoat is discharged onto the substrate surface, then coating is achieved, but dripping and leakage occur causing uneven profiles and operational inefficiencies
Solution Approach 1:
The patent applies pneumatic principles by using a vacuum system to create negative pressure within the showerhead interior. This pressure differential prevents washcoat from dripping or leaking from the showerhead outlets, ensuring controlled discharge and uniform coating profiles on the substrate surface.
Solution Approach 2:
The vacuum system is activated before washcoat discharge to pre-establish the negative pressure environment within the showerhead. This preliminary action ensures that the washcoat remains contained and controlled during the entire coating process, preventing dripping and leakage before they can occur.
2Quantity of substance
If multiple doses of washcoat are applied to portions of the substrate, then coating coverage is increased, but back pressure increases due to excessive coating
Solution Approach 1:
The vacuum system maintains negative pressure within the showerhead to precisely control washcoat discharge. This prevents excessive washcoat application and ensures uniform distribution, avoiding the buildup that would increase back pressure in the substrate while maintaining adequate coating coverage.
Solution Approach 2:
The vacuum system provides continuous control over washcoat flow by maintaining a constant pressure differential. This feedback mechanism ensures that washcoat is discharged at the correct rate and distribution, preventing over-coating that would lead to increased back pressure while ensuring sufficient coverage.
3Manufacturing precision
If washcoat is pulled through the substrate body, then coating penetration is achieved, but washcoat emerges from the lower face causing visual degradation
Solution Approach 1:
The vacuum system is activated before washcoat discharge to pre-establish the negative pressure environment within the showerhead. This prevents excessive washcoat formation on the upper face and controls the coating process to achieve penetration without over-application that would cause washcoat to emerge from the lower face and cause visual degradation.
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 reduces or eliminates washcoat dripping and leakage, ensuring a uniform coating profile and minimizing operational inefficiencies, thereby enhancing the performance and longevity of the coated substrates.
Implementation Method 1
the valve assembly creates a pressure drop within an interior of the washcoat showerhead when the outlet valve moves from its open state to its closed state
Implementation Method 2
preventing dripping and leakage by generating a suction force
Implementation Method 3
drawing the washcoat through the substrate by applying a suction force to a lower surface of the substrate
Data Source
AI summary
An apparatus and a method for coating substrates with washcoats in which a substrate (10) is engaged with a headset (6) of a substrate coating apparatus (1) below a washcoat showerhead (5) are disclosed. The washcoat is discharged from the washcoat showerhead (5) onto an upper surface (12) of the substrate under control of a valve assembly (4) before being drawn through the substrate by use of a vacuum generator (7). The valve assembly (4) comprises an outlet valve movable between a closed state and an open state. The valve assembly (4) creates a pressure drop within an interior of the washcoat showerhead (5) when the outlet valve moves from its open state to its closed state.