String Wound Filter Cartridge
String Wound Filter Cartridge – FAQ
Everything You Need to Know About String Wound Filter Cartridges
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1. What is a string wound filter cartridge
A string wound filter cartridge is made by winding polypropylene, cotton, or glass fibers around a core in a precise pattern to form a depth filtration structure with a loose outer layer and tight inner layer for effective particle capture.
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2. What applications are suitable for string wound cartridges?
Commonly used in water treatment, chemical filtration, pre-filtration for resin systems, and industrial liquids containing suspended solids and rust.
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3. What filtration ratings are available?
Filtration ratings usually range from 1 µm to 50 µm, depending on the material type and winding density.
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4. How does the string wound structure improve filtration?
The gradient density structure traps contaminants throughout the filter depth, providing high dirt-holding capacity, effective particulate removal, and low pressure drop.
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5. What are the maximum operating temperatures?
Standard polypropylene cartridges can operate up to 200 °C, while glass fiber and specialty materials may tolerate higher temperatures.
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6. What is the maximum differential pressure?
Typically, string wound cartridges can handle up to 0.21 MPa at ambient temperature; the allowable differential pressure decreases at elevated temperatures.
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7. Can string wound cartridges be backwashed or reused?
Some designs allow backwashing, especially for industrial water treatment, but most standard cartridges are disposable.
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8. What materials are used in string wound cartridges?
Filter media include polypropylene yarn, degreased cotton yarn, or glass fiber. Cores are usually high-strength PP or stainless steel.
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9. What sizes and connection types are available?
Lengths range from 10" to 40", with outer diameters of 63 mm or 115 mm and inner diameters of 28 mm or 30 mm. Various end caps are available to fit standard housings.
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10. When should the cartridge be replaced?
Replace the cartridge when the pressure drop reaches the manufacturer’s recommended limit or filtration efficiency decreases due to accumulated particles.