Composite Air Filter Medium for Low Pressure Loss Filtration
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Solution Overview
Problem
Existing air filters face challenges in achieving a balance between effective particle collection efficiency and low pressure loss, while also maintaining a long service life without excessive clogging.
Innovation Solution
The air filter medium incorporates first fibers with an average diameter of 5 μm to 50 μm and second fibers with an average diameter of 30 nm to 1 μm, entangled and mixed to form a composite film, with a specific weight and thickness ratio to optimize dust collection and reduce pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter medium with small fiber diameter is used to improve collection efficiency, then particle collection efficiency is improved, but pressure loss increases
Solution Approach 1:
The filter medium employs a bimodal fiber distribution where small-diameter fibers (30 nm to 1 μm) are strategically positioned in the gaps between large-diameter fibers (5 μm to 50 μm). This local differentiation allows small fibers to provide high collection efficiency in critical gap regions while large fibers maintain open pathways for airflow, resolving the contradiction between collection efficiency and pressure loss.
Solution Approach 2:
The filter medium combines two distinct fiber types with different diameter ranges (30 nm to 1 μm and 5 μm to 50 μm) into a composite structure. This composite approach leverages the advantages of both small fibers (high collection efficiency) and large fibers (low pressure loss) to achieve optimal performance balance.
2Reliability
If a dense filter structure is used to improve collection efficiency, then particle collection efficiency is improved, but service life decreases due to clogging
Solution Approach 1:
The filter structure creates local density variations where small-diameter fibers concentrate in gap regions to provide high collection efficiency, while large-diameter fibers maintain overall structural openness. This local quality differentiation allows effective particle capture without creating uniformly dense structures that would lead to rapid clogging and reduced service life.
Solution Approach 2:
The filter medium segments its fiber population into two distinct size categories with specific functional assignments: small fibers (30 nm to 1 μm) for particle capture in gap regions, and large fibers (5 μm to 50 μm) for maintaining structural integrity and airflow pathways. This segmentation prevents uniform densification and extends service life by reducing clogging.
3Reliability
If small diameter fibers are used to improve collection efficiency, then PF value is improved, but device complexity increases
Solution Approach 1:
The invention changes the critical parameter from fiber diameter alone to a bimodal distribution of fiber diameters with specific ranges (30 nm to 1 μm and 5 μm to 50 μm). This parameter transformation allows achieving high PF values through a structured mixture rather than using only ultra-fine fibers, thereby reducing the practical complexity of fiber handling and processing while maintaining high collection efficiency.
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 solution enhances collection efficiency for particles of 0.4 μm with a PF value of 16 or more, extends the filter life by maintaining low pressure loss, and reduces clogging, thereby improving overall filter performance.
Implementation Method 1
a filter medium layer (65). The filter medium layer includes first fibers and second fibers
Data Source
AI summary
A method of producing an air filter includes a first step of preparing a tow band and a second step of obtaining a filter medium layer that includes first fibers obtained by applying tension to the tow band to spread the tow band and the first fibers having an average fiber diameter of 5 μm or more and 50 μm or less and second fibers disposed in gaps between the first fibers and having an average fiber diameter of 30 nm or more and 1 μm or less. The second fibers are drawn out from the particulate resin by drawing the particulate resin, and the particulate resin is drawn by separating the first fibers from each other so that a gap is formed between the first fibers during the spreading of the tow band.