A polymer producer in Asia operating multiple polyethylene lines needed a more reliable filtration approach for high-viscosity polymer melt processing. Standard metal candle filters that performed well in conventional PET production were not suited to the elevated viscosity, flow distribution and mechanical stress demands of LDPE processing.
Pall developed an application-specific candle filter design to help improve operational stability, reduce rapid differential pressure buildup and strengthen filter element reliability under demanding high-viscosity conditions.
The Challenge
The customer’s existing filtration system struggled to maintain stable performance in high-viscosity LDPE melt processing. Under these conditions, elevated viscosity limited flow distribution and increased mechanical stress on the filtration media, leading to rapid differential pressure buildup, process interruptions, media sleeve deformation and difficult cleaning due to polymer retention.
As production shifted toward higher-viscosity grades, the customer required a filtration design that could better withstand demanding operating conditions, support longer run lengths and reduce maintenance complexity.
Representative media deformation examples: media sleeve pinching and media sleeve twisting.
The Pall Solution
Pall’s engineering team developed a customized filtration solution based on a standard metal candle filter platform, with targeted enhancements designed for high-viscosity polymer melt systems.
The upgraded configuration addressed two critical challenges: improving flow distribution through the element and increasing mechanical stability during extended operation and cleaning cycles.
Key design improvements included re-optimized pleating geometry to reduce localized pressure buildup, a removable media sleeve design to simplify maintenance, reinforced internal support to help prevent sleeve pinching and twisting, and enhanced cleanability to reduce polymer hold-up.
Together, these enhancements helped the customer better manage the rheological behavior of high-viscosity polymers while maintaining a practical retrofit path from conventional filtration designs.
Results
Following installation, the customer reported sustained operational improvements over one to two years of continuous production.
- Stable operation: The upgraded filtration system significantly reduced rapid differential pressure buildup, helping support more consistent production and improved throughput.
- Improved mechanical reliability: The enhanced support structure helped eliminate failure modes such as media sleeve pinching and twisting.
- Reduced maintenance: Longer operating cycles and lower cleaning frequency improved equipment utilization and helped reduce maintenance demands.
- Enhanced cleanability: Reduced polymer residue accumulation enabled faster, more efficient cleaning with lower labor requirements.
Customer Validation
Following successful operation, the customer initiated retrofit projects across additional production lines, replacing competitor filter elements. The expansion demonstrated confidence in the performance of Pall’s design and reinforced its suitability for high-viscosity polymer applications.
Conclusion
This case demonstrates that filtration systems designed for lower-viscosity polymers may not meet the demands of high-viscosity processing. By tailoring the filter design to the application, Pall helped the customer improve process stability, strengthen element reliability and reduce maintenance complexity.
These design principles may also apply to other demanding high-viscosity polymer applications as producers shift toward higher-performance materials, recycling processes and circular material streams. Potential applications include high-viscosity polyolefins, engineering plastics, advanced specialty polymers and recycling processes where stable filtration is critical to product quality, productivity and operating efficiency.
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