Embossed PTFE Filter Medium Minimizing Pressure Loss
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Solution Overview
Problem
Embossing processes for air filter filtration media made from PTFE porous films result in increased pressure loss due to the low mechanical strength of PTFE, which can lead to film rupture and further pressure loss when subjected to external forces.
Innovation Solution
Incorporating a fibril-formable polytetrafluoroethylene (PTFE) with a non-fibril-forming and non-hot-melt-processable component and a non-fibril-forming and hot-melt-processable component having a melting point below 320°C, supported by air-permeable materials, to enhance the mechanical strength and stability of the filtration medium during the embossing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If PTFE porous film is used as filtration medium, then pressure loss is reduced compared to glass fiber media, but mechanical strength is insufficient causing film rupture under external forces
Solution Approach 1:
The patent combines PTFE porous film with a heat-resistant porous substrate to create a composite filtration medium. The PTFE layer provides low pressure loss and high filtration efficiency, while the substrate provides mechanical strength and structural support. This composite structure resolves the contradiction by allowing the PTFE film to function optimally without bearing the full mechanical load.
Solution Approach 2:
The patent employs a porous heat-resistant substrate with controlled pore structure that maintains air permeability while providing mechanical support. The porous structure allows air flow to pass through with minimal resistance, preserving the low pressure loss characteristic of PTFE media while the substrate framework prevents film rupture under external forces.
2Stability of the object's composition
If embossing process is applied to PTFE porous film to create projections for maintaining pleat spacing, then structural stability is improved, but film structure is crushed and pressure loss increases
Solution Approach 1:
The patent performs embossing on the heat-resistant porous substrate before attaching the PTFE porous film. This preliminary action creates the projection structure in the substrate that will maintain pleat spacing, while the PTFE film is subsequently attached to conform to this pre-formed structure, avoiding direct embossing of the fragile PTFE film itself.
Solution Approach 2:
The composite structure allows the embossing process to be applied to the robust substrate without damaging the PTFE film. The substrate's mechanical strength enables it to withstand the embossing pressure, creating stable projections that maintain pleat spacing while the PTFE layer remains intact and preserves low pressure loss characteristics.
3Ease of manufacture
If PTFE porous film is subjected to compressive forces during layering on support material, then filtration medium is formed, but film structure ruptures and pressure loss rises
Solution Approach 1:
The patent structures the composite so that the heat-resistant porous substrate serves as the primary load-bearing component during fabrication and operation. The PTFE porous film is applied as a functional layer that requires minimal compressive force for attachment, thus avoiding film rupture while still enabling effective filtration medium formation.
Solution Approach 2:
The patent assigns different functional qualities to different layers: the substrate provides mechanical strength and structural stability throughout, while the PTFE film provides localized high-efficiency filtration. This differentiation allows the PTFE film to be handled gently during manufacturing while still achieving effective filtration medium formation.
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 minimizes the rise in pressure loss associated with the embossing process, maintains filter performance, and extends the lifespan of the filtration medium by limiting film thickness reduction and preventing leak defects.
Implementation Method 1
a non-fibril-forming and hot-melt-processable component having a melting point below 320°C
Implementation Method 2
compressive forces acting on the PTFE porous film in the thickness direction when the PTFE porous film is layered on an air-permeable support material
Data Source
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AI summary
Provided are an embossed air filter filtration medium, a filter pack, and an air filter unit, with which a rise in pressure loss associated with the embossing process is minimized; and a method for manufacturing an embossed air filter filtration medium with which the rise in pressure loss associated with the embossing process is minimized. The embossed air filter filtration medium is an embossed air filter filtration medium for trapping dust in a stream of air, provided with one or a plurality of porous films that include a fibril-formable polytetrafluoroethylene, a non-fibril-forming and non-hot-melt-processable component, and a non-fibril-forming and hot-melt-processable component having a melting point below 320°C; and a plurality of air-permeable support materials supporting the porous film. The surfaces of both sides of the embossed air filter filtration medium are formed by two air-permeable support materials among the plurality of air-permeable support materials, and the air filter filtration medium is furnished with a plurality of projections by undergoing an embossing process.