Embossable Filter Medium With Bimodal Fiber Distribution
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Solution Overview
Problem
Existing air filter media, particularly those made from glass fibers, face challenges in maintaining pleat spaces and extending lifespan when subjected to embossing due to the risk of layer destruction and clogging, especially when exposed to air pressure.
Innovation Solution
A filter medium with a main collection layer having a specific fiber diameter distribution and volume ratio, combined with an upstream collection layer, which allows for embossing without fiber destruction and maintains airflow efficiency, is designed. This layer configuration includes fibers with small and large diameters in a balanced ratio, ensuring effective dust holding capacity and medium-performance collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If glass fiber filter medium is embossed to maintain pleat spaces, then pleat space maintenance is improved, but layer structure is destroyed and crushed
Solution Approach 1:
The patent changes the physical parameters of the filter medium by using polypropylene fibers with specific diameter distribution (bimodal distribution with 0.5μm and 2.0μm peaks) and controlled filing rate (5-15%), making the material embossable while maintaining structural integrity. This allows the filter medium to withstand embossing pressure without layer destruction, enabling convexity formation for pleat space maintenance.
Solution Approach 2:
The patent creates a composite fiber structure combining fine fibers (0.1-0.8μm) and coarse fibers (1.0-3.0μm) in a specific volume ratio (30:70 to 80:20). This composite structure provides both the flexibility needed for embossing and the structural strength to prevent layer crushing, resolving the contradiction between embossability and layer integrity.
2Ease of manufacture
If filter medium thickness is reduced for easier pleating, then ease of manufacture is improved, but collection efficiency may deteriorate
Solution Approach 1:
The patent optimizes the thickness parameter to 0.35-0.70mm, which is thin enough to enable easy pleating with mountain folds and valley folds, yet maintains sufficient collection efficiency through the bimodal fiber diameter distribution and controlled filing rate. This parameter optimization resolves the contradiction between manufacturability and performance.
Solution Approach 2:
The patent applies local quality by creating regions with different fiber characteristics - the bimodal fiber distribution provides both fine fibers for particle capture (maintaining collection efficiency) and coarse fibers for structural support (enabling thin design for easy pleating). This local differentiation of fiber functions allows simultaneous achievement of thin design and high efficiency.
3Reliability
If fiber diameter is reduced for better particle capture, then collection efficiency is improved, but clogging increases and life decreases
Solution Approach 1:
The patent employs a composite fiber structure with bimodal diameter distribution, combining fine fibers (0.1-0.8μm, 30-80% volume ratio) for high collection efficiency with coarse fibers (1.0-3.0μm, 20-70% volume ratio) to maintain pore structure and prevent clogging. This composite approach allows the filter to capture particles effectively while extending service life by reducing dust holding capacity issues.
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 filter medium achieves extended lifespan and improved dust holding capacity while maintaining airflow efficiency, even when embossed, by using a balanced fiber diameter distribution and volume ratio, reducing clogging and pressure drop, and enhancing collection efficiency.
Implementation Method 1
a main collection layer... an upstream collection layer disposed on an upstream side of the main collection layer in an airflow passing direction
Implementation Method 2
the filter medium is less likely to become clogged, and the life thereof can be extended (dust holding capacity will increase)
Data Source
AI summary
Provided are a filter medium for an air filter capable of having extended life even when composed of embossable material. The filter medium (1) has a tensile elongation of 10% or greater, and includes a main collection layer (30) having a filing rate of 5% to 15%, a thickness of 0.35 mm to 0.70 mm, and a peak in a fiber diameter distribution at less than 1.0 μm and a peak at 1.0 μm or greater. An average fiber diameter of small fiber diameters of less than 1.0 μm is from 0.1 μm to less than 0.8 μm, and an average fiber diameter of large fiber diameters of 1.0 μm or greater is from 1.2 μm to less than 3.0 μm. A volume ratio of the fibers having the small fiber diameter to the fibers having the large fiber diameter is from 30:70 to 80:20.