Description
20 Inch Big Blue Melt Blown Sediment Filter with Three-Layer Construction for Whole House and Commercial Systems
Overview
A spun poly filter cartridge (also called a melt blown or spun type filter cartridge) is a depth sediment filter made from thermally fused polypropylene fibers. The Franklin FWPS 20" x 4.5" uses three layers of micro-denier melt blown polypropylene, with the coarsest fibers on the outside and the finest near the core. This traps sediment at multiple depths rather than just on the surface, which increases dirt-holding capacity and extends service life. NSF 42 certified for material safety requirements and FDA CFR Title 21 compliant. Four micron ratings: 1, 5, 20, 50. Flow rates from 12 to 20 GPM.
Specifications
| Specification | Detail |
|---|---|
| Series | FWPS (20" Big Blue) |
| Filter Type | Melt blown (spun poly), depth filter |
| Media | 100% Melt-Blown Micro-Denier PP Fiber |
| Construction | Three-layer, thermal bonded, no binders or adhesives |
| Size | 20" x 4.5" OD (Big Blue) |
| Micron Ratings | 1 (FWPS20B01), 5 (FWPS20B05), 20 (FWPS20B20), 50 (FWPS20B50) |
| Max Operating Temperature | 65°C (150°F) |
| Nominal ΔP for Replacement | 1.5 Bar (22 psi) |
| Max Pressure Drop @ 20°C | 3.2 Bar (46.4 psi) |
| Max Flow Rate | 45-75 Lpm (12-20 GPM)* |
| Certifications | NSF 42 (material requirements), FDA CFR Title 21 |
| Case Quantity | 6 |
| Case Dimensions | 33 x 28 x 104 cm (13 x 11 x 41 in) |
| Case Weight | 5.44 kg (12 lbs) |
*Flow rate depends on micron rating. Lower micron = lower max flow.
Single-Gradient vs Dual-Gradient: Which 20" Big Blue Spun Poly Do You Need?
Cleanflow carries two melt blown spun poly cartridges in the 20" x 4.5" Big Blue format. Both are NSF 42 certified. The difference is how the micron rating is structured:
FWPS (this cartridge) has a single micron rating throughout. You choose 1, 5, 20, or 50 micron, and the entire cartridge is built to that rating. Straightforward: one cartridge, one job.
FWPS-DG (dual gradient) has two micron ratings in one cartridge, paired as outer/inner layers (25/1, 50/5, or 75/25 micron). The outer layer catches coarse sediment while the inner layer handles fine particles. This combines two filtration stages into a single cartridge, which can replace a two-cartridge setup in systems with mixed particle sizes.
Choose the FWPS when your sediment is consistent and one micron rating covers it. Choose the FWPS-DG when your water has both coarse and fine sediment and you want to consolidate two stages into one cartridge.
Key Features
- 20 inch length doubles the dirt-holding capacity and flow rate of the 10" Big Blue version, which means longer service intervals and fewer cartridge changes in high-throughput systems.
- 100% polypropylene media is chemically resistant, bacteria resistant, and will not add taste, color, or odor to the water. Thermal bonding eliminates the need for binders or adhesives.
- The three-layer gradient density structure distributes sediment load across the full depth of the media, extending service life compared to single-density filters at the same micron rating.
- NSF 42 certified by NSF International for material safety requirements. FDA CFR Title 21 compliant for food-contact applications.
Applications
- Whole-house sediment filtration
- Commercial water systems
- Pre-filtration for reverse osmosis membranes
- Industrial process water and chemical processing
- Food and beverage production
- Electroplating
- Water purification systems
Buy 20" Big Blue Spun Poly Filter Cartridges from Cleanflow
Cleanflow carries the Franklin FWPS 20" Big Blue spun poly sediment filter in all four micron ratings (1, 5, 20, 50). Browse the full Big Blue Water Filters collection or explore the complete Franklin Water lineup. Sold individually or by the case (6).
Need the 10" version? The FWPS 10" x 4.5" Big Blue fits shorter housings. Prefer a washable filter? The FWPL 20" pleated is reusable and available in the same format. Free shipping on orders over $199. 30-day return policy at returns.cleanflow.net. Call 1-866-335-1078 or email info@cleanflow.ca for case pricing.
Frequently Asked Questions
How do poly spun filters work?
Water enters from the outside of the cartridge and flows inward toward the core. As it passes through the layered melt blown media, particles are trapped at different depths depending on their size. Because sediment loads gradually across the full thickness of the media rather than clogging at one surface, pressure rises slowly over time and the cartridge holds more total sediment before needing replacement.
What is the difference between the FWPS and FWPS-DG at this size?
The FWPS has one micron rating throughout. The FWPS-DG pairs two ratings in one cartridge (coarse outer, fine inner). See the comparison above for guidance on when to choose each.
How often should I replace a 20 inch Big Blue sediment filter?
Replace when the pressure drop across the housing reaches 1.5 Bar (22 psi) above the clean-cartridge baseline. This is the nominal replacement threshold from the spec sheet. The maximum allowable pressure drop is 3.2 Bar (46.4 psi). The 20" cartridge holds more sediment than the 10", so replacement intervals are longer under the same water conditions.
Can this spun poly filter be used before an RO system?
Yes. The FWPS is commonly used as a sediment pre-filter to protect RO membranes from sand, silt, and rust. For a complete RO pre-filtration setup, pair the FWPS with a carbon block filter to remove chlorine, which damages RO membranes over time.
What is the difference between NSF 42 certified and FDA grade?
NSF 42 means the product was tested by NSF International and the materials passed NSF/ANSI Standard 42 for safety in contact with drinking water. FDA CFR Title 21 means the polypropylene is approved for food-contact use. The FWPS carries both. Some Franklin filters (like the FWSW string wound) carry FDA grade only without NSF certification. Both are safe for potable water, but NSF 42 provides third-party verification.
Manuals & Documentation
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