How to Select the Suitable String Wound Filter Cartridge?

String Wound Filter Cartridges are depth filter elements manufactured by precisely winding textile fiber yarns. They feature outstanding advantages including high dirt holding capacity, stable differential pressure during filtration, compact structure and wide compatibility. Capable of efficiently trapping various impurities in fluids while maintaining cost-effectiveness, they stand as the preferred consumables for coarse filtration and pre-treatment filtration across all industries.

How to Choose the Right Wound Filter Cartridge

1. Select According to Filtration Working Conditions

Different fluids like clean water, industrial wastewater, corrosive chemicals and oils require matched cartridges with specific corrosion and temperature resistance. Standard cartridges fit normal-temperature low-pressure environments, while high-temperature and high-pressure scenarios demand cartridges with corresponding temperature and pressure resistance to avoid deformation, cracking and leakage. For heavily contaminated fluids, high dirt-holding cartridges are recommended, and standard versions work well for clean, low-impurity liquids.

2. Selection Based on Filter Cartridge Material

Material is the core factor determining the temperature resistance, safety and service life of string wound filter cartridges. Materials vary greatly in core performance and applicable scenarios. You need to pick the proper material matching your actual working conditions to prevent filtration failure and secondary contamination caused by mismatched materials. There are three mainstream materials for wound filter cartridges on the market:

PP Polypropylene String Wound Filter Cartridge: As the most widely used universal type with outstanding cost performance, PP material features excellent acid and alkali resistance, corrosion resistance and anti-aging property with superior chemical stability, barely reacting with common fluids. It has a compact structure, uniform filtration performance, no fiber shedding and no impurity precipitation. It is perfectly suitable for neutral fluid filtration such as pure water, tap water, general industrial water and circulating water, covering most civil and conventional industrial pre-treatment applications. It lowers daily maintenance costs with high practicality, making it the top choice for general scenarios.

Hongtek PSW Series Filter Cartridges adopt high-precision winding technology with a gradient structure that is loose on the outer layer and dense on the inner layer. They feature large dirt holding capacity and stable differential pressure. Perfectly compatible with all kinds of conventional neutral fluid filtration conditions, they balance premium quality and cost-effectiveness, making them the top high-quality choice for industrial pre-treatment and civil water purification.

Bleached Cotton String Wound Cartridge Filters: Compared with PP material, absorbent cotton boasts better air permeability and gentler filtration without contaminating raw liquids. It has moderate adsorption capacity, which can effectively intercept impurities while retaining the original quality of fluids. It is specially designed for filtration scenarios with strict hygiene requirements, including drinking water, beverages, wine, dairy products and food raw liquid, serving as the exclusive optimal choice for food and drinking water industries.

Hongtek CSW Series Filter Cartridges, it is designed as honeycomb-shap to ensure no short fibers break away. In addition, bleached cotton string wound cartridges provide high flow rate, good chemical resistance, excellent efficiency filtration and long service life. Cotton string wound filters are widely used in industrial oil/water separation, petrochemical process, power plant water treatment and many other crucial industrial fields.

Glass Fiber String Wound Filter Cartridge: It is a high-performance special filter cartridge, with far superior high temperature resistance and corrosion resistance than ordinary PP and cotton materials, suitable for filtration of high-temperature fluids and strongly corrosive chemical liquids. Its stable material structure resists deformation, damage and failure under high temperature and special acid-base environments, delivering consistent filtration accuracy and strong anti-interference performance. It is mainly applied in harsh working conditions such as industrial high-temperature water treatment, fine chemical industry and special fluid filtration, solving complex filtration problems that standard cartridges cannot handle.

Hongtek GSW Series Filter Cartridges are elaborately manufactured with high-purity glass fiber. They feature excellent heat resistance, strong acid and alkali resistance and outstanding chemical stability, customized for harsh industrial conditions involving high temperature and heavy corrosion. Adopting precise winding technology, the cartridges own solid structure and uniform filtration accuracy. 

3. Selection Based on Support Core Structure

Many buyers tend to overlook the support core structure when selecting filter cartridges. However, the core directly determines the cartridge's supporting strength, pressure resistance and service life to fit operating conditions with different pressures and flow rates. Wound filter cartridges are equipped with two types of cores for distinct application scenarios:

PP Inner Core: The PP core provides basic supporting strength to effectively prevent looseness, delamination and deformation of filter cartridges. It delivers good permeability and low water flow resistance with remarkable cost performance. Hongtek PSW series string wound filter cartridges adopt integrally molded food-grade high-toughness PP polypropylene cores. It can operate stably and durably under steady pressure without drastic fluctuations, greatly cutting equipment maintenance and consumable costs, making it a cost-effective option for general applications.

SUS304 / 316 Stainless Steel Core: For high-temperature filtration applications, aside from heat-resistant absorbent cotton or glass fiber media, the inner core must also be made of high-temperature resistant materials to suit the operating environment. SUS304 inner cores fit most conventional high-pressure industrial scenarios with reliable corrosion resistance and durability, while SUS316 inner cores deliver superior acid, alkali, temperature and corrosion resistance, offering a far longer service life than cartridges with PP cores. Hongtek ESW Series filter cartridges are equipped with stainless steel inner cores featuring stable structure, anti-aging property and long service life. They are tailor-made for harsh industrial applications.

4. Selection Based on Size Specifications

Size specifications are the foundation to ensure smooth installation and operation of filter cartridges. Most wound filter cartridges on the market follow standard dimensions, including 10", 20", 30" and 40", compatible with the majority of general filtration equipment. For large-scale industrial water treatment projects, 50-inch and 70-inch extra-long wound cartridges are frequently required. Hongtek string wound filter cartridges adopt mature one-piece integrated core technology. Unlike ordinary spliced segmented cores, the full-length integrated core has no splicing gaps, featuring better structural integrity and higher rigidity, which greatly improves the overall pressure resistance and deformation resistance of large-size cartridges.

In addition, two mainstream outer diameter specifications are widely adopted in the industry: standard 63/65mm outer diameter and 114mm large outer diameter, designed for different filtration equipment. The 63/65mm standard outer diameter is the most universal size, matching most standard 10/20/40-inch filters and small industrial filters for pre-treatment applications. Cartridges with 114mm outer diameter provide higher flow rate and larger dirt holding area, widely used in main pipeline filtration, large water treatment systems and high-flow circulating filtration to meet heavy-duty high-volume filtration demands. Thanks to the winding manufacturing process of string wound cartridges, custom outer diameters are available upon special requests.

Conclusion

Ultimately, no universal wound filter cartridge suits all applications. The key is to select the right material, core structure, precision and size based on actual working conditions and fluid properties. Proper selection ensures stable filtration performance, reliable equipment operation and lower long-term maintenance costs.