The selection of filter bag material or fabric media is a critical aspect of dust collector design, as it directly impacts the service life and filtration efficiency of the system. The chosen filter fabric must be chemically and physically compatible with the process gas stream and operating conditions. Properly selected filter bags significantly reduce emissions, and with the right media choice, emission levels as low as 10 mg/Nm³ can be achieved.
Working Principle of Pulse Jet Dust Collector
A pulse-jet dust collector consists of one or more compartments containing rows of cylindrical fabric filter bags or pleated cartridges. Dust-laden air flows upward along the outer surface of the bags and then passes radially through the filter media. Dust particles are captured on the outer surface of the bags, while the cleaned air exits through the outlet.
As dust accumulates, the pressure drop across the filter bags increases. Once it reaches a predefined limit, compressed air pulses are released into the bags, dislodging the dust cake. The collected dust falls into the hopper and is discharged through a Rotary Airlock Valve (RAL). The dust cake formed on the filter surface plays a key role in achieving filtration efficiencies of up to 99.9% for micron-sized particles.
Key Factors in Filter Bag Selection
Selecting the correct filter bag fabric depends on multiple parameters, including:
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Dust fineness and particle size
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Moisture content
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Operating temperature
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Type and abrasiveness of dust
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Chemical characteristics of the process gas
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Fiber permeability
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Cleaning energy resistance
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Fabric flexibility and durability
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Installation and maintenance conditions
Choosing the Right Filter Bag Fabric
A wide range of filter fabrics are available for pulse-jet bag filters, such as Polyester, Polypropylene, Acrylic, PTFE, Aramid, Ryton (PPS), Glass Fiber, and Ceramic fibers. Additionally, specialized surface treatments and coatings are applied depending on application needs.
For high-temperature applications up to 260°C, glass fiber filter bags are commonly recommended. Different industrial processes may require filter media suitable for oily, moist, explosive, or ultra-fine dust environments. Therefore, correct fabric selection plays a vital role in the overall performance and reliability of the bag filter system.
Woven vs Non-Woven Filter Fabrics
Non-Woven Fabrics
Non-woven filter media are created by entangling fibers rather than weaving them. These fabrics offer high strength and durability, making them ideal for aggressive applications such as pulse-jet dust collectors.
Woven Fabrics
Woven filter fabrics consist of threads interlaced in a uniform pattern. They are generally used in low-intensity cleaning systems like reverse air or shaker-type collectors. The weave pattern influences the fabric’s strength, permeability, and filtration efficiency.
Surface Treatments for Filter Bags
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PTFE Membrane
A thin PTFE (Teflon) membrane is thermally bonded to the filter fabric surface to enhance filtration efficiency and dust cake release. Although relatively expensive and delicate, PTFE membranes provide superior filtration performance. -
Singed Finish
Loose fiber ends are removed by exposing the fabric surface to an open flame. This treatment improves dust release and reduces particle adhesion. -
Calendering (Glazing)
The fabric is passed through heated rollers to create a smoother surface, improving dust cake release and filtration stability. -
Fire Retardant Treatment
A chemical coating applied to reduce the risk of ignition from occasional sparks. While not fireproof, it enhances operational safety. -
Acid Resistant Treatment
Improves the fabric’s resistance to acidic gases and corrosive environments. -
Antistatic Treatment
Conductive fibers or stainless-steel scrims are integrated into the fabric to dissipate static charges, reducing explosion risks and ensuring safe operation.
Applications of Filter Bags
Filter bags are widely used in industries such as:
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Cement and minerals
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Steel and metal processing
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Power plants
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Food and spice processing
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Pharmaceuticals
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Chemicals and petrochemicals
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Oil & gas industries
Did You Know?
With over 30 years of industry experience, PURITEC Clean Air Systems has successfully served 3000+ customers worldwide, delivering reliable dust collection and air filtration solutions across diverse industries. Our advanced in-house filter bag manufacturing facility ensures consistent quality, performance, and customized solutions for every application.
