PTFE Membrane Laminated Filter Medium for Mechanical Stability
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Solution Overview
Problem
Filter media used in industrial fluid filtration applications face mechanical stress issues during cleaning, leading to potential de-needling and transverse fractures due to high mechanical stresses.
Innovation Solution
A filter medium with a porous polytetrafluoroethylene membrane laminated on one side, combined with a supporting fabric of glass or basalt fibers and a small proportion of polytetrafluoroethylene staple fibers, anchored using a fluorinated polymer adhesive, enhances mechanical stability and prevents de-needling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the filter medium is cleaned using the Puls-Jet process with compressed air impulses, then the dust cake is effectively removed from the filter, but the staple fibers become detached from the fabric and mechanical damage occurs to the fabric
Solution Approach 1:
The invention uses a composite structure consisting of a supporting fabric made of mineral yarns (glass or basalt) and a membrane made of expanded porous polytetrafluoroethylene (PTFE). This composite material combines the high mechanical strength and thermal stability of mineral fibers with the chemical resistance and porosity of PTFE, creating a filter medium that can withstand the mechanical stresses of the Puls-Jet cleaning process while maintaining filtration performance
Solution Approach 2:
The PTFE membrane acts as a flexible thin film layer that is laminated onto the supporting fabric. This membrane provides additional mechanical reinforcement and flexibility, allowing the filter medium to deform elastically during the Puls-Jet cleaning process without causing staple fiber detachment or fabric damage, thereby maintaining reliability under dynamic cleaning conditions
2Productivity
If the fabric is covered with polymer staple fibers by needling, then the filter medium achieves the required filtration performance, but the staple fibers are prone to de-needling under mechanical stress
Solution Approach 1:
The invention creates a composite structure where the PTFE membrane is laminated onto the supporting fabric. This membrane provides additional anchoring points for the staple fibers through its porous structure, enhancing the stability of fiber attachment. The combination of mineral yarns and PTFE membrane creates a multi-layer composite that secures staple fibers more effectively than a single fabric layer, preventing de-needling under mechanical stress while maintaining the necessary filtration performance
Solution Approach 2:
The PTFE membrane is used in an expanded porous form, which provides a three-dimensional network structure with numerous pores and surface areas. This porous structure allows staple fibers to interlock and anchor within the membrane's pore structure, significantly improving fiber retention. The porous nature also maintains filtration efficiency by allowing fluid passage while trapping particles, achieving both filtration performance and fiber anchoring stability
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 significantly improves the mechanical stability of the filter medium, preventing staple fiber detachment and transverse fractures, while maintaining high temperature resistance and chemical resistance, even under high mechanical stress conditions.
Implementation Method 1
a membrane made of porous polytetrafluoroethylene is laminated on at least one side of the filter medium
Implementation Method 2
the membrane is attached to the filter medium by means of an adhesive
Implementation Method 3
a membrane made of expanded porous polytetrafluoroethylene with an air permeability of at least 0.01 m 3 per m 2 per hour at a water column of 12.7 mm
Data Source
Figure 1
AI summary
The subject matter is a filter medium which comprises a woven fabric (1) made from mineral yarns, which woven fabric (1) is covered with polymeric staple fibres (2) by needling. There is provision here for a diaphragm (3) made from porous polytetrafluoroethylene to be applied at least on one side of the filter medium, in particular on its inflow side.