Medium Filters

Medium efficiency filters — including bag filters (V-Bag / pocket filter) — serve as the second-stage core of air filtration systems, rated F7 (ePM1 ≥50%), F8 (ePM1 ≥70%), and F9 (ePM1 ≥85%) under EN 779, corresponding to ePM1 and ePM2.5 under ISO 16890. They effectively capture particles in the 1–10μm range — atmospheric dust, bacteria carriers, combustion products, and fine fibers — providing critical pre-protection for downstream HEPA/ULPA filters and extending HEPA service life by 2–3×.

Main structural types include V-Bag filters with extended bag surfaces offering high dust-holding capacity for variable air volume systems; Mini-Pleat V-type filters with dense pleating for low initial pressure drop in depth-constrained installations; and Rigid Cell filters with robust construction suited for secondary filtration in high-cleanliness environments. Selection parameters should cover filtration efficiency, rated airflow, initial and final pressure drop, and dust-holding capacity curves.

Typical applications: AHU return-air filtration for cleanrooms, GMP clean zones in pharmaceutical facilities, negative-pressure isolation rooms in healthcare, secondary filtration in electronics manufacturing, and precision machining plants.