Waterproof and Oil-Proof Filter Bags

Waterproof and Oil-Proof Filter Bags

Waterproof and oil-proof filter bags are industrial filtration components specially treated with coatings or fiber modifications to impart hydrophobic and oleophobic properties to their surface.They are designed to effectively address issues of dust adhesion and clogging in high-humidity or oil-laden flue gas.Suitable for medium-to-low temperature conditions ranging from 80°C to 200°C,they are widely used in applications involving wet or oily smoke,such as asphalt mixing,food processing,machining,and spray painting.These bags can consistently achieve emission standards with an outlet dust concentration of≤10 mg/m³.

The waterproof and oil-proof functionality is primarily achieved through two technical approaches:

Surface Coating Process:A low-surface-energy coating,such as PTFE or silicone,is applied to the base filter material(e.g.,polyester,PPS).This forms a"waterproof and oil-proof film,"making it difficult for water and oil molecules to adhere to the bag surface(contact angle can reach≥110°),thus preventing dust from agglomerating due to moisture or oil.

Fiber Modification Process:Hydrophobic and oleophobic groups are introduced into the molecular structure of the fibers(e.g.,modified polyester fibers),enhancing the bag's anti-adhesion capability at the source and avoiding functional failure due to coating detachment.

During operation,dust containing moisture or oil is intercepted by the filter bag.Due to the non-stick surface characteristics,the dust can rapidly detach,reducing cleaning difficulty.

Core advantages are reflected in three aspects:

Anti-Adhesion and Clogging Prevention:Effectively handles flue gas with a moisture content≤35%and oil content≤5 mg/m³.Prevents dust from absorbing moisture,caking,or clogging the bag due to oil adhesion,ensuring long-term stable operation.The cleaning cycle is extended by 2 to 3 times compared to standard filter bags.

Strong Adaptability:Different base materials can be selected according to operational needs(e.g.,polyester for 80–150°C,PPS for 150–200°C),meeting both waterproof/oil-proof and temperature resistance requirements without compromising filtration accuracy.Capture efficiency for dust particles≥0.5μm reaches≥90%.

Extended Service Life:Reduces bag wear and corrosion caused by dust adhesion.Under standard operating conditions,the service life can reach 2–3 years,representing a 30%–50%increase compared to conventional filter bags.

Limitations primarily relate to temperature resistance and chemical stability:

Coated bags generally have a long-term temperature resistance limit of≤200°C.Exceeding this temperature can cause coating degradation and detachment.

They are not resistant to strong solvents(e.g.,acetone,ethanol),which may dissolve the coating and compromise the waterproof/oil-proof function.

Typical application scenarios include:

Asphalt mixing plants:Handling smoke containing asphalt oil mist and dust,temperatures 120–160°C.

Food processing plants:Managing fumes from frying or baking,containing oils and moisture.

Machining workshops:Handling oil-laden dust from metalworking fluid mist,temperatures 80–120°C.

Spray painting industry:For pre-treatment of paint spray exhaust,containing paint mist and solvent vapors.

Currently,advancements are being made through the development of more heat-resistant coatings(e.g.,ceramic composite coatings)and optimized coating adhesion processes.These efforts aim to further enhance temperature resistance and durability,expanding their application in demanding wet and oily dust collection scenarios.