Classification of Common Filter Bag Materials for Water Treatment

Filter bagshave an extremely wide range of applications, used in industries such as pharmaceuticals, petrochemicals, automotive manufacturing, paints, coatings and adhesives, food and beverages, electronic processes, water treatment, and metal processing. In water treatment, the commonly used filter bags are roughly divided into:

① PET (Polyester) fiber filter bags;

② Polypropylene (PP) fiber / PP microfiber filter bags;

③ Nylon monofilament filter bags;

④ Special high-temperature resistant PTFE (Polytetrafluoroethylene) filter bags, etc.

Today we will briefly introduce these types of filter bags:

▲ Nylon filter bags: Made of high-strength nylon woven mesh with sewn construction. The advantages of nylon filter media are reusability after repeated cleaning and low cost. However, as a surface filtration mode, they are prone to clogging, making them suitable for coarse filtration scenarios with low precision requirements.

▲ PP filter bags: Constructed from polypropylene fiber filter cloth. PP filter media belong to depth-type filtration materials, featuring excellent chemical resistance, high flow rate with low resistance, no pollution, and a long service life. Thus, they are widely and economically applied in industry.

▲ PE filter bags: Made of polyester fiber filter cloth. The loose fiber structure increases the contaminant holding capacity; this product adopts a composite interception mode, effectively removing solid and soft particles.

▲ PET filter bags: Based on polyethylene terephthalate, a high polymer. It is an off-white or pale yellow, highly crystalline polymer with a smooth and glossy surface. PET filter media also fall into the depth-type category, offering excellent chemical and solvent resistance—especially outstanding corrosion resistance against solvent-based fluids. Similar to PP fibers, PET can withstand higher operating temperatures (160℃).

▲ PTFE filter bags: Also known as Teflon filter bags, these are among the high-end varieties of bag filter materials. They can operate continuously at 240℃ and withstand instantaneous temperatures up to 260℃, while resisting acid and alkali corrosion across the entire pH range.

For filter bags, in addition to understanding the materials, it is also necessary to grasp filtration precision. Two units are commonly used for filter bag precision: "Mesh" and "Micron". However, the relationship between them is not widely understood. Therefore, we have compiled a corresponding table of "Mesh" and "Micron" for reference in practical work.