Description

20‑inch Security Filter, Pure‑water Filter, Pre‑RO Filter, 20‑inch 5‑cartridge Stainless‑steel Filter

Precision filters (security filters) mostly adopt stainless‑steel housings equipped with filter cartridges such as PP cotton. They are placed after multimedia pre‑treatment filtration and before membrane separation equipment including reverse osmosis and ultrafiltration units. Their function is to trap fine particles carried over from multimedia filtration, such as fine quartz sand and activated‑carbon fragments. This guarantees effluent water quality and protects downstream membrane elements from damage by large‑particle contaminants.

Available cartridge precision grades include 0.5 μm, 1 μm, 5 μm, 10 μm, etc. Different precision ratings are selected according to process requirements to secure both outlet‑water quality and the service life of subsequent membrane components.

Cartridges of PP cotton, nylon, melt‑blown and other materials remove fine suspended solids, bacteria and other impurities from water, bringing feed‑water up to the inlet specifications for reverse‑osmosis membranes.

1. Process Principle

As a type of precision filter, the security filter performs mechanical filtration via the 5 μm pores of PP cartridges. Trace suspended particles, colloids, microorganisms and other contaminants remaining in the feed‑water are trapped or adsorbed on the cartridge surface and within its pore structure. As operation continues, accumulated contaminants increase pressure drop across the filter. Cartridges shall be replaced once the differential pressure between inlet and outlet reaches 0.1 MPa. Security filters feature high filtration efficiency, low flow resistance and easy cartridge replacement.

2. Structure & Operating Principle

Security filters use pre‑formed filter media. Under pressure, raw liquid passes through the filter medium; solid residues are retained on the medium surface while filtrate permeates through to the outlet, achieving solid‑liquid separation. Common filter media include filter cloth, filter screen, filter discs, sintered filter tubes, wound cartridges and melt‑blown cartridges. Pore‑size varies with filter‑medium type.

Precision filtration sits between sand filtration (coarse filtration) and ultrafiltration, with typical pore sizes ranging from 0.5 μm to 120 μm. The same filter‑medium type is available in multiple physical dimensions.

Wound cartridges (also known as honeycomb cartridges) come in two main versions:

Polypropylene‑fiber / polypropylene‑core cartridges: maximum operating temperature 60 °C

Absorbent‑cotton‑fiber / stainless‑steel‑core cartridges: maximum operating temperature 120 °C

Melt‑blown cartridges are manufactured from polypropylene via melt‑blown technology, with a maximum service temperature of 60 °C. Precision filtration removes suspended solids, certain colloidal substances and fine particulate matter from liquids.

3. Technical Specifications

4. Application

Security and final‑stage filtration for nanofiltration (NF), ultrafiltration (UF), reverse osmosis (RO), electrodialysis (EDI) and other systems; 

Filtration for pharmaceutical injectables, large‑volume infusions, eye drops, herbal‑medicine liquid extracts; extraction, purification and concentration of biological preparations; 

Pre‑filtration and final‑stage filtration for high‑purity water in electronics, microelectronics and semiconductor industries;

Filtration for oil‑field reinjection water, boiler make‑up water, chemical reagents, organic liquid products, high‑purity chemicals, pesticide formulations, etc.;

Filtration for drinking purified water, mineral water, fruit juice, tea beverages and health drinks;

Clarification filtration for liquor, wine, beer, rice wine and other fruit wines; sterile filtration for draft beer (alternative to pasteurization);

Pre‑treatment / security filtration for industrial & domestic wastewater treatment and recycled‑water reuse;

Other applications: bioengineering, oil refining, feed‑water & wastewater treatment for printing‑dyeing & textile industries, laboratory‑scale experimental filtration, etc.