About String Wound Filters

A Time-Tested Technology, Refined for Modern Industry

String wound filters have been a trusted solution in fluid filtration for over half a century. Developed in the 1930s and gaining widespread use in the 1950s and 60s, string wound filters were originally designed for high-purity industrial processes where surface filters failed to provide adequate particle retention and longevity. Their durability, versatility, and effectiveness made them the gold standard across industries—from municipal water treatment to pharmaceuticals.

At Durable Filter Manufacturing, we’ve spent over 60 years perfecting this proven technology. Today, our string wound filters continue to outperform more recent filter types by delivering what matters most: reliable, consistent, depth filtration.

How String Wound Filters Work

String wound filters are engineered using a highly controlled manufacturing process where carefully selected filtration media—such as polypropylene, cotton, or polyester—is wound onto a core using specialized equipment that ensures precise tension, patterning, and density..

This advanced depth structure allows contaminants to be captured at multiple levels within the filter—not just on the surface—resulting in true depth filtration that performs reliably even under demanding conditions.

This design delivers critical advantages:

· Exceptional dirt-holding capacity

· Extended filter lifespan

· Stable, low pressure drop

· Fewer changeouts and reduced maintenance

· Reliable performance under pressure and flow variation

 Why Choose String Wound Filters Over Other Types?

While newer technologies like melt blown, pleated, or spun bonded filters have entered the market, they often focus on cost savings over long-term performance. Here’s how string wound filters stand apart: