Melt-blown cartridges are made of fine polypropylene fibers bonded into a depth filter that becomes denser towards the core. They trap sand, rust and suspended particles and are the most widely used cartridge before RO membranes. Big Blue versions fit 4.5 inch housings for higher flow.
Key features
- Low cost, easy to replace
- Depth filtration with good dirt-holding capacity
- Standard (Ø60 – 64 mm) and Big Blue (Ø110 – 115 mm) sizes
- Replace when pressure drop reaches 1 bar
Choosing and replacing cartridges
- How many cartridges? A standard PP cartridge (Ø60–64 mm) handles up to about 1.1 m³/h per 10 inches of length. For 20 m³/h, use a 5 × 40″ housing (22 m³/h) or a 7 × 30″ housing (23.1 m³/h).
- Filter rating: 5 µm is the usual choice before RO. Melt-blown, string-wound and carbon membrane cartridges are rated nominally; some RO membrane makers recommend 5 µm absolute, so tell our engineers if your RO system requires it.
- When to replace: when the pressure drop across the cartridge reaches 1 bar, or when a carbon cartridge is saturated. In front of RO membranes, DuPont recommends replacing cartridges at least every 3 months.
- Melt-blown or string-wound? Both are PP, 10″–40″, 5 µm. Melt-blown works up to 60 °C with a maximum pressure drop of 3.0 bar; string-wound works up to 90 °C with 2.7 bar.
- Big Blue or standard housing? Big Blue housings are Ø148 mm with 1″ ports for fat Ø110–115 mm cartridges, 0–4.5 m³/h (10″) or 0–9 m³/h (20″). Standard housings are Ø92 mm with 1/2″–3/4″ ports, 0–1.1 or 0–2.2 m³/h.
