Urea Filter Element with Dual Permeability Media
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Solution Overview
Problem
Existing urea solution filters face challenges in preventing the accumulation of large gas bubbles, which can disrupt the functioning of downstream components, particularly nozzles, during the filtration process.
Innovation Solution
A filter element comprising a fluid-permeable and gas-impermeable first filter medium and a liquid-impermeable and gas-permeable second filter medium, arranged between the raw and clean sides, where the first medium filters out unwanted particles and the second medium facilitates the continuous transport of small gas bubbles, preventing their accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter medium is used for filtering urea solution, then the filtration structure is simple, but gas bubbles accumulate in the filter element disrupting downstream component function
Solution Approach 1:
The filter element is divided into two distinct filter media with different permeability characteristics. The first filter medium (hydrophilic) is liquid-permeable but gas-impermeable, while the second filter medium (hydrophobic) is liquid-impermeable but gas-permeable. This segmentation allows each layer to perform its specific function: the first layer filters particles from the urea solution, while the second layer allows accumulated gas bubbles to escape, preventing disruption to downstream nozzles.
Solution Approach 2:
Different regions of the filter element are assigned different material properties to address local functional requirements. The first filter medium is positioned to handle liquid filtration where hydrophilic properties are needed, while the second filter medium is positioned to handle gas venting where hydrophobic properties are required. This local differentiation of material properties enables simultaneous particle filtration and gas bubble removal.
2Productivity
If vacuum is applied to the urea solution output, then the filtration process is enhanced, but gas accumulates in the highest region of the filter element
Solution Approach 1:
The second filter medium acts as an intermediary layer between the first filter medium and the filter housing. It mediates the gas accumulation problem by providing a controlled pathway for gas bubbles to escape from the filtration zone to the venting zone, while maintaining the vacuum-enhanced filtration process through the first hydrophilic filter medium.
3Reliability
If the first filter medium is made gas-permeable to allow gas passage, then gas bubbles can escape, but liquid filtration efficiency is reduced
Solution Approach 1:
The filtration function is segmented into two separate layers: the first layer (hydrophilic) is optimized for liquid filtration with gas-impermeable properties, while the second layer (hydrophobic) is optimized for gas passage with liquid-impermeable properties. This segmentation allows each layer to excel at its specific function without compromising the other.
Solution Approach 2:
Different permeability qualities are assigned to different layers based on local functional requirements. The first layer has high liquid permeability and low gas permeability for efficient particle filtration, while the second layer has low liquid permeability and high gas permeability for effective gas bubble removal.
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
Effectively prevents the accumulation of large gas bubbles within the filter element or device, ensuring the smooth operation of urea solution filtration and protecting downstream components from potential damage.
Implementation Method 1
a first filter medium (6), folded in the form of a bellows, which is fluid-permeable and gas-impermeable
Implementation Method 2
a second filter medium (23), which is liquid-impermeable and gas-permeable
Implementation Method 3
provide a compensation body made of elastically deformable material. The compensation body absorbs an increase in the freezing of urea solution
Data Source
Figure 1
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Figure 3
AI summary
The invention relates to a filter element (3) for filtering a fluid, in particular an urea solution, comprising a liquid-permeable and gas-impermeable first filter medium (6) and a liquid impermeable and gas permeable second filter medium (23). The first and second filter mediums (6, 23) are arranged between a dirty side and a clean side (41, 42) of the filter element (3).