Polyester filter bags are widely used in industrial dust removal under normal temperature conditions due to their good mechanical properties, high filtration efficiency and moderate price. In order to improve the performance of polyester needle felt filter bags in actual working conditions, such as filtration accuracy, cleaning ability, chemical resistance and service life, different types of post-treatment are often required on their surfaces. The following are several common surface treatment processes for polyester filter bags and their characteristics and applicable scenarios.
1. Singeing
Principle and purpose:
Singeing is to use flames or hot rollers to burn the floating hair on the surface of the filter material to make its surface smoother. After the polyester fiber is singed, it can effectively prevent dust from penetrating into the fiber, forming a "deep filtration", thereby reducing the difficulty of cleaning.
Features:
The surface is neater and dust embedding is reduced
Improve the cleaning performance and reduce the running resistance
Improve the appearance and dimensional stability of the filter bag
Applicable scenarios:
Suitable for most common dust environments, such as woodworking, building materials, light industry and other industries, especially for occasions where the dust is fine but not sticky.
2. Calendering
Principle and purpose:
Calendering is to compact the surface of the filter material through high temperature and high pressure roller pressure, so that its density increases and the pores become smaller. This treatment can enhance the surface tightness of the filter material, improve its filtration accuracy, and form a more stable initial dust layer.
Features:
Increase surface flatness and improve filtration efficiency
Improve the peeling property of dust, which is conducive to dust cleaning
Improve structural stability and extend the life of the filter bag
Applicable scenarios:
Applicable to industries with high emission requirements, such as precision machinery, grain processing, food packaging, etc.
3. Coating treatment (PTFE coating)
Principle and purpose:
PTFE (polytetrafluoroethylene) coating is to firmly adhere the microporous film to the surface of the needle felt through hot pressing technology to form a smooth and dense filter layer. Its function is to achieve "surface filtration" and prevent dust from penetrating the filter material.
Features:
Extremely high filtration efficiency, emissions can reach ultra-low emission standards
The surface is dust-free, easy to clean, and the resistance is stable
Extend the life of the filter bag and reduce the maintenance frequency
Applicable scenarios:
Applicable to occasions where the dust is ultra-fine, easy to agglomerate, or the emission standards are strict, such as pharmaceutical, electronics, food, chemical and other industries.
IV. Waterproof and oil-proof treatment (W/O treatment)
Principle and purpose:
By coating or impregnating the surface of the filter material with a hydrophobic and oil-repellent agent, it has the properties of moisture-proof, anti-condensation, and anti-oil pollution, thereby preventing the filter bag from sticking and caking due to moisture or oil.
Features:
Enhance the adaptability of the filter bag in high humidity or oily dust environments
Prevent dust from absorbing moisture and adhering, and reduce the difficulty of cleaning
Delay the aging of the filter material and increase the service life
Applicable scenarios:
Applicable to production processes with more moisture and oil smoke, such as metallurgy, spraying, carbon black, and casting.
5. Anti-static treatment (Anti-static)
Principle and purpose:
By mixing conductive fibers (such as stainless steel fibers or carbon fibers) into polyester fibers or adding conductive additives, the filter material is made conductive, thereby preventing the accumulation of static electricity from causing sparks or explosion risks.
Features:
Prevent dust explosions caused by static electricity
High safety, especially suitable for combustible dust environments
Good mechanical properties and filtration efficiency
Applicable scenarios:
Applicable to collection sites for flammable and explosive dust such as coal powder, flour, wood powder, and plastic powder.
6. Coating treatment (such as silicone oil treatment)
Principle and purpose:
By coating specific chemicals such as silicone oil, acrylic resin, etc. on the surface of the filter material, its chemical stability, corrosion resistance or surface properties are improved.
Features:
Enhance acid and alkali resistance, antioxidant properties, etc.
Improve the surface tension of the filter material and improve the ash discharge capacity
Improve the ability to resist hydrolysis or chemical corrosion
Applicable scenarios:
Applicable to environments containing lightly corrosive gases or high humidity.
Summary and comparison
Main function of surface treatment type Applicable occasions Does it affect the price
Singeing treatment makes cleaning easier and prevents dust embedding. Generally, dust is low
Calendaring treatment improves density and filtration accuracy. Fine dust is low
Laminating treatment has ultra-high filtration efficiency and high standard of surface filtration. Environmental protection industry has been significantly improved
Waterproof and oil-proof treatment prevents sticking bags, condensation, high humidity, and oil-containing working conditions have increased slightly
Antistatic treatment eliminates spark hazards High in flammable dust environments
Coating treatment enhances corrosion resistance Special chemical environments depend on materials
Conclusion
The surface treatment process of polyester needle felt filter bags is crucial to improving their comprehensive performance. According to the physical properties, temperature and humidity, chemical composition and equipment operation mode of the dust, choosing the right surface treatment method can significantly extend the life of the filter bag, improve the dust removal efficiency, and ensure the safe, stable and economical operation of the dust removal system. Therefore, in the selection process, not only the filter material substrate should be considered, but also the required surface treatment method should be fully considered to meet the dust removal needs under specific working conditions.