Bimodal Pore Ceramic Filter for High Efficiency Low Pressure Drop
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Solution Overview
Problem
Current particulate filters with ceramic honeycomb bodies face challenges in achieving high filtration efficiency and maintaining low pressure drop at high particulate loading, while also accommodating catalyst material loading without significant pressure drop increases.
Innovation Solution
A particulate filter design featuring a ceramic honeycomb body with a bimodal pore size distribution, comprising intersecting walls formed from an interconnected network of porous spheroidal ceramic beads with specific intrabead and interbead porosities, allowing for high filtration efficiency and low pressure drop through capillary action and large flow passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic honeycomb body uses a uniform pore structure, then manufacturing is simpler, but filtration efficiency at high particulate loading decreases and pressure drop increases
Solution Approach 1:
The patent applies local quality by creating different pore size regions within the ceramic walls. The microstructure contains both small pores (0.5-5 μm) and large pores (5-20 μm) in specific spatial arrangements, where small pores provide filtration surfaces and large pores provide flow passages. This local differentiation of pore qualities enables high filtration efficiency while maintaining low pressure drop at high particulate loading.
Solution Approach 2:
The patent uses composite microstructure by combining different pore size distributions within the same ceramic material. The dual-mode pore structure acts as a composite of filtration-functional pores and flow-functional pores, allowing the material to simultaneously achieve high filtration efficiency and low pressure drop characteristics that neither uniform pore structure could provide alone.
2Reliability
If catalyst material is loaded into the ceramic honeycomb body, then catalytic conversion capability improves, but pressure drop increases
Solution Approach 1:
The patent applies local quality by designating specific pore regions for catalyst loading while maintaining other regions for flow passage. The large pores (5-20 μm) serve as catalyst support zones where catalyst material can be loaded without significantly blocking flow, while the small pores (0.5-5 μm) remain as flow passages. This spatial separation allows high catalyst loading with minimal pressure drop increase.
Solution Approach 2:
The patent uses porous materials with controlled pore size distribution to accommodate catalyst material. The porous ceramic structure with dual-mode pores provides sufficient surface area and volume for catalyst loading while maintaining open flow pathways. The large pores specifically serve as catalyst hosts without creating significant flow resistance.
3Stress or pressure
If the ceramic walls have high porosity to reduce pressure drop, then flow characteristics improve, but filtration efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by assigning different functional qualities to different pore regions. Small pores (0.5-5 μm) are designated for filtration with higher surface area to volume ratio, while large pores (5-20 μm) are designated for flow passage with lower resistance. This local functional differentiation allows the wall to simultaneously achieve high filtration efficiency and low pressure drop.
Solution Approach 2:
The patent creates a composite pore structure that combines filtration-functional small pores and flow-functional large pores within the same ceramic wall material. This composite microstructure enables the wall to exhibit both high filtration efficiency and low pressure drop characteristics, resolving the trade-off between these two opposing requirements.
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 bimodal pore size distribution enables high filtration efficiency and low pressure drop across varying particulate loads, while allowing for high catalyst loading without significant pressure drop increases, maintaining effective filtration and flow characteristics.
Implementation Method 1
allowing for high filtration efficiency and low pressure drop through capillary action and large flow passages
Data Source
AI summary
A particulate filter and method of manufacture. The particulate filter comprises a ceramic honeycomb body comprising a plurality of intersecting walls that define a plurality of channels extending longitudinally though the ceramic honeycomb body. The intersecting walls comprise a porous ceramic material having a microstructure that comprises an interconnected network of porous spheroidal ceramic beads. The microstructure has a total porosity defined as the sum of an open intrabead porosity of the beads and an interbead porosity defined by interstices between the beads in the interconnected network. The microstructure has a bimodal pore size distribution in which an intrabead median pore size of the intrabead porosity is from 1.5 μm to 4 μm and an interbead median pore size of the interbead porosity is from 6 μm to 20 μm.