Filter disc BKG® FlexDisc™

Overview
The patented BKG® FlexDisc™ is a filter stack technology that replaces the standard screen in the filter cavities of piston-type melt filters. It substantially enlarges the effective filtration area without increasing machine size or weight and reduces melt loss caused by backflushing. The FlexDisc™ enables very fine filtration (20 µm and lower) for contaminated polymer melts and is especially suited for high-quality end products such as battery separator film.

Key Advantages

• Significantly enlarged filtration area within existing machine dimensions.
• Reduced melt loss and lower specific backflush volume thanks to fewer required backflushes.
• Prolonged lifetime of the filtration medium, lowering spare-parts and operating costs.
• Enables fine filtration down to 20 µm and below for high-end applications.
• Retrofit-capable for multiple piston screen changer platforms.

Benefitting Your Process

• Higher throughput at the finest filtration levels without larger machines.
• Lower polymer usage and operating costs due to reduced backflush waste.
• Reduced spare parts costs from longer filter life and robust design.
• Retrofittable to BKG® HiCon™ V-Type 3G, BKG® HiCon™ K-SWE-4K-75/RS and BKG® NorCon™ D-SWE screen changers.

Increase Profitability

• Leverage overall line efficiency by realizing a larger filtration area and higher throughput without increasing machine footprint.
• Reduce spare parts costs through prolonged filter media life.
• Save polymer usage with a lower specific backflush volume due to fewer backflush cycles.
• Robust design minimizes spare-parts costs and supports retrofitting to existing equipment.

Increase Quality

• Achieve filtration fineness down to 20 µm and lower to ensure a clean melt for demanding products (for example, battery separator films).
• Less shear stress on the melt preserves molecular structure, improving end-product quality.

Increase Convenience

• Reduced operator intervention because the FlexDisc™ design enables effective backflushing, keeping production lines running with minimal interruption.

Suitable Applications

• Bottle-to-bottle recycling (rPET) — fine filtration to remove labels, metals, paper and other contaminants to produce virgin-like rPET.
• PET fiber production — filtration fineness of 25–30 µm to protect screen packs on spinning lines.
• Battery separator film production — ultra-fine filtration (20 µm and below) to avoid defects and ensure smooth production runs.

Case Studies & Performance Highlights

• With BKG® HiCon™ K-SWE-4K-75/RS equipped with the FlexDisc™, reported melt loss during backflushing was reduced to about 1.4–1.7% in PET bottle-to-bottle recycling, significantly lower than typical values.
• Customers reported a 40% reduction in backflush amount compared with conventional backflush filters and an increase in filter life from about 8 hours to 72 hours when using the FlexDisc™.

Available Literature (titles)

• BKG® FlexDisc™ Data Sheet
• BKG® Filtration Accessories Data Sheet
• BKG® FlexDisc™ Case Study — Ice River
• BKG® FlexDisc™ Case Study — Starlinger
• BKG® TechTip: Producing Virgin-Like rPET

Technical specifications

• Filtration fineness: achievable down to 20 µm and lower.
• Designed to substantially enlarge filtration area without increasing machine size or weight.
• Reduces melt loss caused by backflushing; reported melt loss ~1.4–1.7% in specific customer setup.
• Can reduce backflush volume (customer report: ~40% reduction vs conventional filter).
• Prolongs filter media life (customer report: filter life increased from ~8 h to ~72 h in one case).
• Retrofit compatibility: BKG® HiCon™ V-Type 3G, BKG® HiCon™ K-SWE-4K-75/RS, BKG® NorCon™ D-SWE.
• Typical applications: PET recycling (bottle-to-bottle), PET fiber production, battery separator film production, and other processes requiring very fine melt filtration.