Porous sintered metal material, method, blend and use.
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Solution Overview
Problem
Existing porous sintered metal bodies used for filtering industrial fluids, particularly in semiconductor and microelectronic processing, face challenges in achieving high removal efficiency for sub-micron particles while maintaining low pressure drop and reduced thickness to accommodate increasing purity demands and smaller device sizes.
Innovation Solution
The development of novel porous sintered bodies with a metal matrix composed of elongate metal fibers connected by sintered metal nodes, formed from a blend of metal particles with different sintering points, allowing for high porosity and reduced thickness without compromising filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter body is made thicker to achieve high particle removal efficiency, then the LRV increases, but the pressure drop increases proportionally
Solution Approach 1:
The patent employs a porous sintered metal structure with optimized porosity (30-70%) that allows high particle removal efficiency through extended surface area and multiple filtration paths while maintaining low pressure drop. The porous structure provides numerous flow paths that reduce resistance compared to dense thick filters.
Solution Approach 2:
The filter uses a composite structure combining metal fibers (60-90% by weight) with organic binder (10-40% by weight), creating a sintered composite material that achieves both mechanical strength and filtration performance. This composite approach allows thin filter design with high LRV by optimizing the combination of fiber content, binder content, and sintering parameters.
2Stress or pressure
If the filter body is made thinner to reduce pressure drop, then the pressure drop decreases, but the particle removal efficiency decreases
Solution Approach 1:
The patent optimizes critical parameters including porosity (30-70%), metal fiber content (60-90%), binder content (10-40%), and sintering temperature to achieve the desired balance between thickness, pressure drop, and LRV. By precisely controlling these parameters, thin filters achieve high removal efficiency without proportionally increasing pressure drop.
Solution Approach 2:
The invention transitions from considering only filter thickness to optimizing multiple dimensions including porosity, surface area, fiber diameter distribution, and pore size distribution. This multi-dimensional optimization allows thin filters to achieve high LRV through increased surface area and optimized pore structure rather than relying solely on thickness.
3Strength
If organic binder is used in the sintered body to form the metal matrix, then the structural integrity is improved, but outgassing occurs during filtration
Solution Approach 1:
The patent carefully controls binder content (10-40% by weight) and sintering temperature parameters to achieve complete binder combustion and removal. The sintering process is optimized to burn off organic materials completely, converting them to gaseous products that escape during the sintering cycle, leaving a fully inorganic, outgassing-free filter structure.
Solution Approach 2:
The patent converts the potential harm of organic binder (outgassing) into a benefit by using the binder as a sacrificial material during sintering. The binder combustion creates porosity and bonding between metal fibers while the organic material is completely removed, leaving no residual carbon or outgassing sources in the final filter product.
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
These porous sintered bodies effectively filter gaseous flows with low pressure drop and high log reduction value (LRV) of at least 3, 5, 7, or 9, even at low gas velocities, making them suitable for high-purity applications in semiconductor and microelectronic processing.
Implementation Method 1
The porous sintered bodies effectively filter gaseous flows with low pressure drop and high log reduction value (LRV) of at least 3, 5, 7, or 9
Implementation Method 2
The shaped article is removed from the mold, treated to remove the organic binder, followed by heating (i.e., sintering)
Data Source
Figure 1
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Figure 3A
AI summary
Described are porous sintered metal bodies, methods of making and using the porous sintered metal bodies, and methods of using the porous sintered metal bodies for commercial applications that include filtering a fluid, including in applications requiring high efficiency (high LRV) filtration.