Melt-Extruded Polyimide Retention Straps for High-Temperature Filter Pleat Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing high temperature filter elements with retention straps face challenges in installation and maintaining axial location, especially at elevated temperatures, leading to reduced adhesive life and increased movement of filtration media during cleaning pulses.

Innovation Solution

The use of melt-extruded amorphous thermoplastic polyimide retention straps, which are circumferentially extended around the filtration media to limit radial movement and maintain pleat stability, fabricated using extrusion methods that incorporate reinforcement structures for enhanced strength and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If known adhesives are used to fasten retention straps, then the retention straps can be secured in place, but the adhesive life expectancy is shortened at elevated temperatures of 190°C to 260°C

Engineering Contradiction:

Improveretention strap securingVSAvoidadhesive life expectancy

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the material parameter from conventional adhesive to melt-extrudable thermoplastic polyimide polymer, which maintains its fastening properties at elevated temperatures up to 260°C. This material substitution resolves the contradiction by providing both secure retention strap attachment and extended service life under high temperature conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The retention strap system uses a composite approach combining thermoplastic polyimide polymer with reinforcement structures (such as wire mesh or fabric). This composite construction provides both the adhesive-like fastening function and the structural strength needed to maintain retention strap position without degrading at high temperatures, thereby extending component life expectancy.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If manual wrapping and fastening of retention straps is used, then installation can be performed, but the retention straps are difficult to install and may not remain in the desired axial location

Engineering Contradiction:

Improveretention strap installationVSAvoidaxial location stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The melt-extruded thermoplastic retention straps are designed to be self-adhering through heat activation. During installation, the straps are wrapped around the filter element and the thermoplastic material is heated to activate its adhesive properties, causing it to bond to itself and the filtration media. This self-service mechanism eliminates the need for separate manual fastening operations and ensures the straps remain securely in the desired axial location without slipping or shifting.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If retention straps are used to prevent filtration media movement, then pleat stability is improved, but the straps must be tightly secured which complicates the installation process

Engineering Contradiction:

Improvepleat stabilityVSAvoidinstallation process

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical fastening system (requiring manual tightening, overlapping ends, and separate fastening operations) with a thermal bonding system. The melt-extruded thermoplastic polyimide straps are heated to melt and bond to the filtration media and to themselves, creating a secure attachment without requiring complex mechanical fastening mechanisms. This substitution simplifies the installation process while maintaining pleat stability under cleaning pulse conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 stable and long-lasting retention system that withstands high temperatures and repeated cleaning pulses, extending filter media life and performance by preventing pleat collapse and maintaining effective filtration.

Implementation Method 1

Each melt-extruded retention strap is formed from a melt extrudable amorphous thermoplastic polyimide

Methodology Applied

Scientific EffectThermal stability of amorphous thermoplastic polyimide:

Implementation Method 2

at least one melt-extruded retention strap extending circumferentially around the filtration media

Methodology Applied

Scientific EffectMelt extrusion: Extrusion

Data Source

PatentEP2189206B1Filter Element with High Temperature Polymer Retaining Straps and Method of Manufacture

Publication Date: 2013.09.25 BHA ALTAIR LLC

Figure 1~2
Figure 3~4
Figure 5~6

AI summary

A filter element (20) is provided. The filter element (20) includes a filtration media (24) formed into a tubular configuration and including a plurality of circumferentially spaced apart pleats (26), and at least one melt-extruded retention strap (82) extending circumferentially around the filtration media to limit radial movement of the filtration media at operating temperatures up to about 260°C (500°F), the at least one melt-extruded retention strap (82, 92) including a melt extrudable amorphous thermoplastic polyimide.