PP Cotton Filter — Function and Filtration Effect
The PP cotton filter (polypropylene spun filter cartridge) is a precision mechanical filter used before the reverse osmosis membrane. Its main function is to intercept suspended solids, sediment, rust, colloids, and other large particles in the water through depth filtration.
Filtration effect:
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Typical filtration rating: 1–5 microns (commonly 5 microns in RO pretreatment).
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Removes most visible particles and fine suspended matter, making the water clearer.
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Protects the high-pressure pump and RO membrane from particle fouling and physical damage.
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Does not remove dissolved salts, heavy metals, or chlorine—these are handled by the RO membrane and activated carbon filter.
The PP cartridge should be replaced when the pressure difference across it increases significantly or according to the maintenance schedule.
