Composite Bag House Filter Media for High Temperature Dust Collection
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Solution Overview
Problem
Current filter media for bag house dust collectors face challenges such as premature failure under high temperatures and oxidizing conditions, low filtration efficiency, blinding, and dimensional instability, especially when subjected to pulse jet cleaning, which limits their effectiveness and lifespan.
Innovation Solution
A composite filter media is developed by bonding a nanoweb layer with a basis weight greater than 2 gsm to a substrate using hydroentanglement or needle punching, providing mechanical stability and uniformity, and is designed to be used in a face-to-face relationship, enhancing particle capture efficiency while minimizing fluid flow restriction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional filter media (fiberglass, polyimide) are used for high temperature applications, then temperature resistance is improved, but chemical resistance and service life deteriorate due to premature failure under oxidizing conditions
Solution Approach 1:
The invention uses a composite structure consisting of a PTFE membrane layer (providing chemical resistance and porosity) laminated to a PTFE nonwoven fabric support layer (providing mechanical strength and thermal stability). This composite approach allows the filter media to simultaneously achieve high temperature resistance (up to 260°C continuous service) and excellent chemical resistance to oxidizing agents, acids, and bases, eliminating the premature failure issue of traditional single-material filters.
2Reliability
If PTFE fabric is used for chemical resistance, then chemical stability is improved, but filtration efficiency deteriorates due to insufficient particle capture
Solution Approach 1:
The invention applies different functional properties to different layers of the composite structure. The PTFE membrane layer (typically 0.1-10 microns thick) provides the filtration function with its controlled porosity and pore structure optimized for particle capture. The PTFE nonwoven fabric support layer provides the chemical resistance and mechanical strength. This local differentiation of functions allows the thin membrane to achieve high filtration efficiency while the support layer maintains chemical stability.
3Manufacturing precision
If membrane thickness is reduced to improve filtration efficiency, then particle capture is improved, but mechanical strength and durability deteriorate
Solution Approach 1:
The composite structure allows the use of a very thin PTFE membrane layer (0.1-10 microns) for high filtration efficiency while the bonded PTFE nonwoven fabric support layer (providing the majority of the basis weight and mechanical strength) ensures durability and resistance to mechanical stress during pulse jet cleaning and installation. The strong bonding between layers ensures they function as a unified structure.
4Strength
If woven fabric support is used for mechanical strength, then structural integrity is improved, but membrane durability deteriorates due to yarn sliding and excessive stress on the membrane
Solution Approach 1:
The invention replaces the traditional woven fabric support with a PTFE nonwoven fabric support layer. The nonwoven structure, composed of randomly oriented bonded fibers, distributes mechanical stresses uniformly across the entire support area rather than concentrating stress at yarn intersection points. This eliminates the yarn sliding problem inherent in woven fabrics and prevents excessive localized stress on the membrane, thereby improving membrane durability during pulse jet cleaning cycles.
5Strength
If basis weight is increased to improve mechanical strength, then durability is improved, but fluid flow restriction increases
Solution Approach 1:
The invention concentrates the basis weight in the support layer (nonwoven fabric) while keeping the filtration layer (membrane) extremely thin with optimized porosity. The support layer's high basis weight provides mechanical strength and durability, while its nonwoven structure with controlled pore size and distribution allows efficient fluid flow. The membrane layer's thinness and optimized pore structure minimize flow resistance, achieving low pressure drop despite the overall higher basis weight of the composite structure.
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 composite filter media demonstrates improved filtration efficiency, reduced pressure drop, and extended cycle time, outperforming traditional media in both pulse-cleaned and non-pulse-cleaned applications, with superior performance at high temperatures and resistance to chemical particulates.
Implementation Method 1
bonding a nanoweb layer with a basis weight greater than 2 gsm to a substrate using hydroentanglement or needle punching
Implementation Method 2
bonding a nanoweb layer with a basis weight greater than 2 gsm to a substrate using hydroentanglement or needle punching
Implementation Method 3
particulate material is removed from a gaseous stream as the stream is directed through the filter media
Implementation Method 4
When the resistance to flow or pressure drop through the textile caused by accumulation of particulate on the filter becomes significant
Data Source
AI summary
A bag filter having a support structure clothed in a filter bag. The cloth of the filter bag is a composite of at least one substrate layer and at least one nanoweb bonded thereto in a face-to-face relationship. The nanoweb is positioned at the surface of the filter bag first exposed to the hot particle laden gas stream and can have a basis weight of greater than about 2 gsm.