Urea-Water Filter Foam Layout for Freeze Pressure Compensation
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Solution Overview
Problem
Existing filtration devices for urea-water solutions in SCR exhaust gas aftertreatment systems are complex, prone to damage during installation, and require time-consuming component replacement, with elastomer membranes posing additional risks and complications.
Innovation Solution
A filtration device with a volume compensation foam arranged between the filter housing and filter, allowing direct contact with the urea-water solution, which is detachable and can be replaced independently, using materials like EPDM for effective volume management during freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomer membrane is used to protect the frost compensation foam from contact with HWL, then the foam is protected from harmful contact, but the device complexity increases and the risk of damage during installation increases
Solution Approach 1:
The patent removes the elastomer membrane and bead structure from the system entirely. Instead of protecting the foam through a separate membrane layer, the foam is directly exposed to the HWL with the understanding that it will be flushed and compensated for volume changes, eliminating the complex membrane arrangement while maintaining system reliability
Solution Approach 2:
Instead of preventing contact between HWL and foam through protective barriers, the patent inverts the approach by allowing direct contact and using the foam's volume compensation capability to handle the HWL expansion during freezing, turning the previously harmful contact into a functional feature
2Reliability
If an elastomer membrane is fitted into the bead of the pump connection housing, then the foam is protected from HWL contact, but the interchangeability of components is reduced and damage risk increases
Solution Approach 1:
The patent extracts and removes the elastomer membrane and bead structure from the pump connection housing, eliminating the complex fitting arrangement that reduced component interchangeability and increased damage risk during installation
Solution Approach 2:
The patent segments the filtration device into modular components (filter housing, filter element, volume compensation foam) that can be independently installed and replaced without complex interactions, improving ease of operation and component interchangeability
3Reliability
If precise fitting is required for the elastomer membrane and pump connection housing, then the sealing is ensured, but the installation time increases and damage risk increases
Solution Approach 1:
The patent removes the elastomer membrane and bead structure that required precise fitting, eliminating the time-consuming and damage-prone fitting process while maintaining sealing through the simplified modular design
Solution Approach 2:
The patent incorporates sealing features directly into the molded components during manufacturing, so that no separate sealing elements or precise fitting operations are needed during installation, reducing both installation time and damage risk
4Strength
If the volume compensation foam is protected from HWL contact, then its structural integrity is maintained, but the pressure compensation effectiveness is reduced
Solution Approach 1:
The patent changes the physical state and properties of the volume compensation foam by using a closed-cell foam structure that can be flushed by HWL. The foam's cells compress and expand in response to volume changes, providing effective pressure compensation while maintaining structural integrity through the closed-cell architecture
Solution Approach 2:
The patent employs a closed-cell foam structure with controlled porosity that allows HWL to flush through the cells without compromising the foam's structural integrity. The porous structure enables volume compensation while the closed-cell design prevents degradation from HWL contact
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 device simplifies installation, reduces damage risk, and enables quick component replacement, effectively managing pressure increases due to freezing without requiring precise fitting, thus ensuring system longevity and efficiency.
Implementation Method 1
the volume compensation foam can be flushed by the urea-water solution. The increase in volume that occurs during freezing therefore acts equally on the volume compensation foam from all sides. In this way, an increase in pressure that is harmful to the components of the filtration device can be counteracted as effectively as possible.
Implementation Method 2
After the diesel engine is switched off, the HWL may therefore freeze at low ambient temperatures. The resulting increase in volume generates high pressure within the filtration device
Implementation Method 3
the volume compensation foam is a closed-cell foam. This is characterised by the fact that the HWL cannot penetrate into the pores of the foam. In the event of an increase in volume of the freezing HWL, the pores are compressed, whereby the pressure increase within the filtration device can be limited.
Data Source
Figure 1~2
Figure 3~4
AI summary
The present inventions pertains a device for filtering an urea-water solution in an SCR exhaust gas aftertreatment device for injecting the urea-water solution into an exhaust gas train, the device having a filter housing and a filter (10) which is arranged in an interior of the filter housing. In order to provide a simpler filtration device in which the susceptibility to damage is reduced and the interchangeability of individual components is increased, the present invention is characterised in that a volume compensation foam (12) is arranged between the filter housing and the filter (10), the volume compensation foam (12) being detachably fastened to the filter (10) in such a way that it can be flushed around by the urea-water solution.