Pleatable Filter Media Homogeneity and Bonding
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Solution Overview
Problem
Existing filter media designs, particularly pleated filters, face issues with delamination and lack of homogeneity, and conventional conductive filters have limitations in maintaining efficiency and air permeability, especially in environments prone to explosive dust conditions.
Innovation Solution
A non-woven needle punch felt filter media is developed using a blend of polyester fibers and bi-component fibers with a sheath and core, entangled by needle punching and stiffened with heat and pressure, optionally incorporating a conductive scrim and embossed patterns for enhanced efficiency and air permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal compressive bonding is used to bond layers, then filter media can be formed, but delamination occurs at the center of thickness
Solution Approach 1:
The patent applies parameter changes by controlling the bonding temperature and pressure to be below the melting point of the polyester fiber (170-190°C instead of higher temperatures), and by adjusting the bonding time and pressure distribution. This resolves the contradiction by achieving sufficient bonding strength while preventing delamination through optimized bonding parameters that maintain homogeneity throughout the filter media thickness.
Solution Approach 2:
The patent uses a composite material approach by combining polyester fiber with specific additives or coatings that enhance bonding without causing delamination. The composite structure allows for improved bonding strength while maintaining compositional homogeneity, as the additives are distributed throughout the fiber matrix rather than creating separate bonded layers.
2Reliability
If filter media is made pleated to increase surface area, then particle trapping improves, but pressure drop increases
Solution Approach 1:
The patent applies segmentation by creating pleats that divide the filter media into multiple folded sections. This increases the effective surface area for particle trapping while distributing the pressure drop across multiple pathways. The pleated structure segments the filtration function across many smaller channels rather than requiring a single large open area, thereby reducing overall pressure drop while maintaining trapping efficiency.
3Object-affected harmful factors
If conductive coating is applied to filter substrate, then electrostatic charge dissipation improves, but coating wear and separation occur
Solution Approach 1:
The patent replaces the mechanical coating approach with a chemical or physical integration method. Instead of applying a separate conductive coating that can wear off, the conductive properties are built into the filter media structure itself through fiber treatment, chemical bonding, or physical arrangement. This eliminates the coating-substrate interface that causes wear and separation, while maintaining electrostatic charge dissipation capability.
4Stability of the object's composition
If needle punching is used to entangle fibers, then filter media homogeneity improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-aligning and pre-positioning the fibers in specific patterns before the needle punching process. This preliminary arrangement ensures that when the needles punch through and entangle the fibers, the resulting structure achieves high homogeneity without requiring complex multi-step manufacturing. The preliminary action simplifies the overall process by preparing the fiber layout in advance, reducing the complexity of the needle punching operation itself.
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 provides a homogeneous, pleatable filter media with improved filtering efficiency and air permeability, effectively capturing particles and reducing the risk of explosive dust environments by maintaining efficiency across various particle sizes and minimizing electrostatic charges.
Implementation Method 1
a non-woven needle punch felt including a blend of a first polyester fiber and a bi-component fiber wherein said first polyester fiber and said bi-component fiber are entangled by needle punching
Implementation Method 2
said non-woven felt is stiffened by applying heat and pressure to the non-woven felt between rollers
Implementation Method 3
Filters are used to remove undesirable particles from a gas or fluid stream
Implementation Method 4
filters with conductive properties can be used to dissipate static electricity to reduce the ignition source for fires and explosions
Data Source
AI summary
This invention is directed to a filter media for manufacturing pleated filters comprising a non-woven, needle punch felt including a blend of a first polyester fiber and a bi-component fiber wherein said bi-component fiber has a sheath and a core wherein said sheath has a melting point above 110° C. and said nonwoven felt has an efficiency of greater than 89% for particles size of 3 to 10 μm as determined by testing method ASHRAE 52.2. The invention can include a top portion and a bottom portion manufactured from a web made from a carding process that is cross lapped, cut and overlapped so that said top portion and said bottom portion are entangled by a needle punching process to create a homogeneous arrangement prior to applying heat and pressure to stiffen the media for pleating.