PP Melt-Blown Cartridge 40" Dual Gradient 5-20 µm

40" polypropylene melt-blown cartridge

Sediment cartridge in pure polypropylene, 40" long, Big One Filter series. Its length provides a very large filtration area, making it suited to high-flow installations and applications needing long service intervals.

The melt-blown process

Melt-blown extrudes molten polypropylene fibres and blows them continuously around a core. The result is a media in one piece, with no binder, no additives and no adhesive, nothing that can migrate into the filtered water.

Against a string-wound cartridge, whose structure is a wound yarn, melt-blown forms a dense web of microfibres. It gives more consistent retention and a lower initial pressure drop at equivalent rating.

Dual gradient 5-20 µm

This is the key feature. Media density is not uniform: the outer layer is open at 20 µm, the inner layer tightens to 5 µm.

Water therefore passes through increasing density. Medium particles, fine sand, rust, pipe deposits, are stopped at the surface, in the open zone. Fines travel further and are retained in depth, in the dense zone.

The benefit is direct: instead of blinding on its outer face like a single-density 5 µm cartridge, this one uses its whole volume. At identical final rating it therefore offers significantly higher dirt-holding capacity and longer service life, decisive at a fine rating, where a conventional cartridge saturates quickly.

5-20 µm or 20-50 µm: which to choose

The two versions in the series answer different positions in the chain.

The 20-50 µm is coarse duty: it absorbs the heavy load at the head of the installation.

The 5-20 µm is fine filtration at high flow. Its 5 µm final rating makes it the last stage before the equipment being protected: softener, membrane, heat exchanger, dosing pump, nozzle. On already de-loaded water it stands alone; on loaded water it sits downstream of a 20-50 µm, which stops it saturating prematurely.

Where to use it

For fine filtration at high flow: collective water treatment, industrial process, irrigation, protection of a softener or a treatment train, prefiltration ahead of RO or UV. The 5 µm rating is the one generally required upstream of a UV lamp, whose performance drops if the water stays turbid.

Replacement

Replacement is driven by pressure drop, not by the calendar. A rising differential pressure across the filter, or a visible drop in flow, signals a blinded cartridge. A saturated cartridge left in place throttles the flow of the whole installation and can eventually release part of what it had captured.