Waterproof&Oil-Resistant&Anti-Static Laminated Filter Bags

Waterproof, oil-resistant, and antistatic coated filter bags use polyester needle-punched felt as the base material. Their antistatic properties are achieved by blending conductive fibers into the warp yarns of the base fabric or by using stainless steel conductive materials. The bags are then finished with a PTFE microporous coating and treated to be water- and oil-repellent, combining “three-proof” characteristics with surface filtration performance. The product typically has a basis weight of 500–550 g/m², a thickness of approximately 1.7–1.8 mm, and an air permeability of 3–5 m³/m²·min.

Its tensile strength is ≥1,000 N/5×20 cm in the warp direction and ≥1,200 N/5×20 cm in the weft direction, with emission concentrations controllable at ≤20 mg/Nm³ or even lower. Its continuous operating temperature generally does not exceed 130°C, with short-term temperature resistance reaching 150°C for 2–10 seconds. These filter bags are suitable for applications with high moisture and oil content, as well as the risk of electrostatic explosions—such as cement coal mills, blast furnace coal injection in steel mills, and coal handling systems in power plants—where they effectively prevent filter bag clogging, improve filtration efficiency, and ensure production safety.

Water- and Oil-Repellent Filter Bags (commonly known in the industry as “Triple-Protection” filter bags: water-repellent, oil-repellent, and anti-static)

Main Base Material: Polyester (PET) needle-punched felt, with conductive fibers (carbon fibers / stainless steel staple fibers) uniformly blended into the fiber matrix to form a continuous conductive network; the surface is thermally laminated with a layer of PTFE microporous film. Process: Whole-fiber impregnation with PTFE emulsion + singeing and calendering treatment

Principle of Operation

The fiber surface is modified using fluorinated PTFE emulsion additives to reduce surface energy and create a lotus-leaf effect; water droplets and oil mist cannot wet the fibers, dust is less likely to absorb water and clump together, and filter bag clogging under condensation conditions is mitigated.

⚠️ Distinction: “Three-Protection” Impregnation ≠ PTFE Coating

“Three-Protection” Impregnation: Modifies the entire fiber, resulting in deep-layer filtration;

PTFE Coating: Laminates a film onto the surface, resulting in purely surface filtration.

Advantages

1. Anti-condensation and anti-clogging: In conditions where flue gas contains moisture, small amounts of oil mist, or hygroscopic dust (clay, raw cement, pulverized coal), dust is less likely to absorb water, agglomerate, and adhere to the filter bags.
2. Good air permeability and low initial resistance: Compared to membrane-coated filter media, it operates at a lower differential pressure at the same filtration velocity, resulting in lower fan energy consumption.
3. Improved dust release: The smooth filter media surface allows the dust cake to detach more easily during pulse-jet cleaning, extending the cleaning cycle.
4. High cost-effectiveness: The cost is significantly lower than that of PTFE-coated filter media; it can be combined with conductive fibers to create three-in-one filter bags that are water-repellent, oil-repellent, and anti-static.
5. Excellent wear resistance, suitable for applications with moderate dust abrasion.

Suitable Applications

Dust collection in cement plant coal mills and raw material silos; blast furnace coal injection; grain processing; chemical drying dust; dust collectors with slight condensation; and environments with humidity between 60% and 85% where there is no significant liquid oil mist.