This 20-inch polypropylene (PP) wound filter cartridge is a professional pre-treatment filtration component engineered exclusively for the security filter links of reverse osmosis (RO) membrane water treatment systems. Manufactured with food-grade, high-purity polypropylene resin as the core raw material and via a high-precision spiral winding process on a rigid PP inner support core, it forms a uniform, graded porous filtration structure. As a critical security filter for RO membranes, its core function is to intercept fine solid particulate impurities in the feed water before it enters the RO membrane system, effectively preventing scratch, blockage and irreversible damage to the high-precision RO membrane elements, thus extending the service life of the RO system and ensuring its stable and efficient operation. It is compatible with all standard 20-inch security filter housings in the water treatment industry, features easy installation and replacement, and contains no adhesives, binders or toxic additives, ensuring no secondary pollution to the feed water and complying with food-grade water treatment material standards.

Tailored for the strict pre-treatment requirements of RO membrane systems, the filtration precision of this 20-inch PP wound filter cartridge is available in high-precision mainstream specifications of 1 μm, 5 μm and 10 μm, with 5 μm being the most commonly used standard specification for RO security filtration. This precision range is scientifically designed to intercept all fine particulate impurities (including silt, clay, rust particles, suspended solids and colloidal particles) that may cause damage to RO membranes, while avoiding excessive flux loss caused by overly fine precision. The graded winding design ensures that the filtration precision is consistent throughout the entire cartridge body, with no local precision deviation, realizing efficient and uniform interception of impurities in the feed water of the RO system.

Under the standard operating conditions of 25℃ ambient temperature and 0.2MPa inlet pressure, the nominal flux of this 20-inch PP wound filter cartridge is 15-25 L/min (liters per minute) for the whole cartridge, with slight variations based on different filtration precision: the 1 μm high-precision model has a nominal flux of 15-18 L/min, while the 5 μm and 10 μm models have a higher nominal flux of 20-25 L/min and 22-25 L/min respectively. The flux design is perfectly matched with the water intake demand of mainstream commercial and industrial RO membrane systems, ensuring sufficient water supply for the RO system while maintaining stable filtration efficiency, and avoiding the problem of insufficient water output of the RO system caused by low flux of the security filter cartridge.

As a physical filtration component for particulate impurity interception, this 20-inch PP wound filter cartridge is not designed with ion separation or rejection functionality, and thus has no salt rejection rate index. Its filtration principle is only to intercept solid particulate impurities based on particle size, and all dissolved inorganic salts, metal ions, small molecule soluble substances and mineral components in the feed water can pass through the cartridge body smoothly and enter the subsequent RO membrane system, where the RO membrane will complete the professional salt rejection process. This functional positioning is consistent with the core role of the RO security filter, focusing on particulate impurity removal without interfering with the subsequent salt rejection operation of the RO system.

The initial pressure drop of a new 20-inch PP wound filter cartridge under the standard nominal flux and 25℃ operating temperature is ≤0.025MPa, which is far lower than the pressure drop limit of RO system security filters, ensuring minimal pressure loss of the feed water in the pre-treatment link. With the continuous operation of the filtration system, as fine impurities are continuously intercepted and accumulated on the surface and inside of the cartridge body, the pressure drop will gradually rise. The recommended maximum operating pressure drop of this cartridge is 0.1MPa; when the pressure drop reaches this value, the cartridge must be replaced in time to avoid excessive feed water pressure loss, which will lead to a decrease in the water production rate of the RO system and an increase in energy consumption.

This 20-inch PP wound filter cartridge adopts a particle size-based physical filtration mechanism, which is fundamentally different from ultrafiltration, nanofiltration and RO membranes that filter substances based on molecular weight. Therefore, it has no specific Molecular Weight Cutoff (MWCO) index. Its interception effect is only aimed at solid particulate impurities with particle sizes larger than its filtration precision, and macromolecular organic substances, colloids and other substances in the feed water can pass through the cartridge body as long as their actual particle size is smaller than the set filtration precision, and then be treated by the subsequent RO membrane system with professional molecular weight cutoff performance.

The effective PP filtration layer thickness of this 20-inch PP wound filter cartridge is 8-12mm, which is thicker than conventional PP wound filter cartridges, and the total outer diameter of the cartridge body is the industry standard 63mm/70mm, matching the internal size of 20-inch RO security filter housings. The thickened effective filtration layer not only ensures a larger impurity holding capacity, effectively delaying the rise of pressure drop and reducing replacement frequency, but also forms a multi-layer graded filtration structure, which can intercept fine impurities step by step and improve the overall filtration efficiency. The inner support core is made of thickened rigid PP material with a thickness of 3-4mm, which ensures the structural stability of the cartridge body and prevents deformation or rupture under the operating pressure of 0.6MPa (the maximum operating pressure of mainstream RO security filters).

The recommended standard replacement cycle of this 20-inch PP wound filter cartridge is 2-4 months when applied to the security filter link of commercial and small industrial RO membrane systems with a daily water production of 1-5 tons. The actual replacement cycle is closely related to the turbidity and suspended solid content of the RO feed water: for feed water with high turbidity (NTU＞5) and high suspended solid content, the replacement cycle is shortened to 2 months; for feed water with low turbidity (NTU＜3) after preliminary pre-treatment, the replacement cycle can be extended to 3-4 months. In addition, the replacement cycle is also determined by the system pressure drop—once the pressure drop reaches the 0.1MPa limit, the cartridge must be replaced immediately, regardless of the actual use time, to protect the RO membrane system. For household large-flow RO water purifiers using this cartridge, the replacement cycle is generally 4-6 months under normal domestic water use conditions.

This 20-inch PP wound filter cartridge has a number of professional performance features adapted to RO membrane security filtration: 1. Food-grade raw material: Adopts 100% high-purity food-grade PP resin, acid and alkali resistant (adapt to water pH value 1-13), corrosion resistant to most inorganic and organic solvents in feed water, with excellent chemical stability; 2. Adhesive-free process: Integral spiral winding forming without any adhesives or binders, avoiding the dissolution of harmful substances into the feed water and ensuring the safety of RO system feed water; 3. High impurity holding capacity: Thickened filtration layer and graded winding structure realize large-capacity impurity storage, delaying pressure drop rise and reducing replacement frequency; 4. RO membrane protection core design: The 1/5/10 μm high-precision filtration range is specially customized for RO membrane pre-treatment, effectively preventing RO membrane scratch and blockage; 5. Strong pressure resistance: Thickened rigid PP inner support core, can withstand the maximum operating pressure of 0.6MPa without deformation or rupture, adapting to the pressure demand of RO system feed water; 6. Standard compatibility: Matches all industry standard 20-inch security filter housings (PP/stainless steel), with unified outer diameter and length specifications, easy installation and replacement without professional tools; 7. Uniform filtration: The high-precision winding process ensures consistent filtration precision of the entire cartridge body, no dead ends, and realizes full-scale and uniform interception of impurities; 8. Environmental protection and recyclable: The whole cartridge is made of single PP material, easy to recycle and treat, in line with green environmental protection requirements of water treatment industry.

This 20-inch PP wound filter cartridge is a dedicated security filter element for RO membrane systems, and its core application fields are all water treatment scenarios equipped with reverse osmosis membrane technology: 1. Commercial RO water purifiers: Used in the security filter link of commercial pure water machines in shopping malls, office buildings, hotels and restaurants, ensuring the safe operation of RO membranes and the production of qualified pure water for daily use; 2. Industrial RO water treatment systems: Applied to the pre-treatment security filtration of industrial pure water and ultrapure water RO systems in electronics, pharmaceutical, food and beverage, chemical and printing and dyeing industries, protecting industrial-grade high-precision RO membrane elements; 3. Household large-flow RO water purifiers: For large-flow household central water purification RO systems, meeting the high water demand of large families and protecting household RO membrane cores; 4. Drinking water engineering projects: Used in the security filter link of RO membrane drinking water purification projects in rural centralized water supply, school and hospital drinking water systems, ensuring the stable operation of large-scale RO systems; 5. Seawater/brackish water desalination systems: As the pre-treatment security filter of small and medium-sized seawater and brackish water desalination RO systems, intercepting fine particulate impurities in seawater/brackish water and protecting the desalination RO membrane; 6. Water reuse systems: Applied to the security filtration of RO membrane systems in industrial wastewater reuse and domestic sewage reclaimed water reuse projects, preventing the blockage of RO membranes by residual impurities in reclaimed water.

In summary, this 20-inch polypropylene wound filter cartridge is a high-performance, professional dedicated security filter element for the pre-treatment of RO membrane water treatment systems, and is a key core component to ensure the stable and efficient operation of RO membrane systems. Its scientific design, tailored for the strict pre-treatment requirements of RO membranes, including the 1/5/10 μm high-precision filtration range, thickened filtration layer, large impurity holding capacity and low initial pressure drop, can effectively intercept all fine particulate impurities in the feed water and fundamentally avoid scratch, blockage and irreversible damage to the high-value RO membrane elements. Made of food-grade high-purity PP raw materials with an adhesive-free winding process, it ensures the safety of feed water and no secondary pollution, complying with the highest material standards of water treatment industry. With the advantages of standard compatibility, easy installation and replacement, strong pressure resistance and wide chemical stability, it is widely applicable to commercial, industrial, household and engineering RO membrane water treatment scenarios, and can significantly extend the service life of RO membrane elements, reduce the maintenance and replacement cost of RO systems, and improve the overall operation efficiency and economic benefits of RO water treatment systems. As a professional security filter for RO membranes, it has irreplaceable important value in the entire reverse osmosis water treatment process, and is the first choice for the security filter link of various RO membrane systems.

The matching related products of this 20-inch PP wound filter cartridge are all core components and supporting equipment of the RO membrane water treatment system, forming a complete RO pre-treatment and filtration product system: 1. 20-inch granular activated carbon (GAC) filter cartridge: Used in the pre-treatment link before this security filter cartridge, to remove residual chlorine, organic matter, odor and color in the feed water, avoiding RO membrane oxidation and pollution; 2. 20-inch compressed activated carbon (CTO) filter cartridge: Installed after the GAC filter cartridge and before this PP wound filter cartridge, for deep adsorption of fine organic matter and colloids, further optimizing the feed water quality of the security filter; 3. 20-inch RO security filter housings: Special supporting equipment for this cartridge, including food-grade PP plastic filter housings (for low-pressure systems) and 304/316 stainless steel filter housings (for high-pressure industrial systems), with standard 20-inch installation size; 4. 20-inch melt-blown PP filter cartridge: An alternative pre-treatment filter cartridge for this wound filter cartridge, suitable for RO feed water with high suspended solid content, can be used interchangeably according to water quality conditions; 5. RO membrane elements: The core protected component of this cartridge, including household, commercial and industrial grade RO membrane elements of various specifications (50G, 100G, 4040, 8040), matching different water production demands; 6. Water treatment supporting accessories: Including filter housing silicone gaskets, pressure gauges, ball valves, quick connectors and filter cartridge pullers, for the installation, sealing and operation monitoring of this cartridge and RO security filter housings; 7. Same series PP wound filter cartridges: Including 10-inch, 30-inch and 40-inch specifications of the same series, adapted to the security filter links of RO systems with different water production and filter housing specifications; 8. RO system water treatment chemicals: Including scale inhibitors, flocculants and membrane cleaning agents, matching with this cartridge to further optimize the operation effect of the entire RO water treatment system and extend the service life of all filter elements and membrane elements.