Acrylic Bag Filter
Acrylic Felt Rated to 130 °C for Humid and Acidic Gases
The acrylic bag filter is a needle-punched felt filter developed for medium-temperature industrial dust collection processes, providing hydrolysis resistance in humid, acidic dusty gases.
500 g/m²
130 °C
150 °C
What Is an Acrylic Bag Filter?
Acrylic bag filters are a medium-temperature dust filtration medium made by the needle-punched felt method from polyacrylonitrile (PAN)-based homopolymer acrylic fibre. In humid, acidic flue gas processes in the 100–130 °C range, where polyester bag filters fall short against hydrolysis and acid corrosion, acrylic felt offers an economical alternative. It shows good chemical resistance to mineral and organic acids and keeps its mechanical stability through high humidity and condensation cycles.
Acrylic’s main limitations are temperature and strong alkaline environments: in processes where the continuous operating temperature is exceeded, fibre strength drops. Offering a cost advantage over PPS and P84, acrylic is a balanced option for processes that combine medium temperature and chemical challenges.
Product Identity and Technical Summary
Key Technical and Structural Features
- Fibre Type
- Homopolymer Acrylic (Polyacrylonitrile) Needle-Punched Felt
- Fabric Structure
- Needle-Punched Felt
- Weight
- 500 g/m²
- Thickness
- 2.0 mm
- Air Permeability
- 150–200 L/dm²·min @ 200 Pa
- Continuous Operating Temperature
- 130 °C (Dry/Humid)
- Peak (Surge) Temperature
- 150 °C
- Chemical Resistance
- Good resistance to mineral and organic acids; moderate resistance to strong alkalis
- Cleaning System Compatibility
- Pulse-Jet
- Reverse Air
- Shaker
Filtration Architecture and Working Principle
Acrylic bag filters pass dirty flue gas or dust-laden industrial air from the outside of the bag to the inside in a two-stage treatment process. The dense needle-punched felt structure combines surface and depth filtration components, effectively capturing a wide range of particles.
Filtration takes place outside-in. Dust-laden gas meets the outer surface of the bag; particles are retained on the surface of the acrylic felt and in the depth of the fibres, and the cleaned gas passes through the fibre structure into the bag and leaves the system at the top. Acrylic fibre’s low moisture absorption stops the felt swelling and the pore geometry distorting in humid processes, giving a stable differential pressure profile.
Surface Filtration
Dust-laden gas meets the outer surface of the bag. While the dense fibre network of the needle-punched felt retains large and medium-sized particles at the surface, with an ePTFE membrane surface treatment fine particles including PM2.5 are also retained on the membrane surface and cannot penetrate into the fibres. Thanks to its low moisture absorption, the felt swells less in humid and wet gases and the filtration surface stays stable.
Cleaning Cycle
The dust cake building up on the bag surface raises the differential pressure. When the set ΔP threshold is reached, the pulse-jet, reverse-air or shaker cleaning system starts. The smooth surface treatment options for acrylic felt (calendering, PTFE coating, ePTFE membrane) let the dust cake separate easily from the surface; in processes with humid and sticky dust, a water- and oil-repellent surface treatment stops the dust cake sticking.
Acrylic Bag Filter Surface Treatment Options
| Surface Finish | Property | Recommended Application |
|---|---|---|
| Calendering | Smooths the surface, improves dust release and ensures compatibility with pulse-jet cleaning systems. | General dry dust applications |
| Singeing | Smooths the surface by singeing the surface fibres and reduces dust re-entraining into the flow. | Processes with a high dust load, cement and lime plants |
| Water and Oil Repellent (PTFE Coating) | Reduces particle adhesion in flue gases containing moisture and oil and increases chemical resistance. | Spray dryers, waste incineration plants and processes with sticky dust |
| PTFE Membrane | Provides surface filtration, PM2.5 retention and high dust release performance. | All applications requiring strict emission limits |
Advantages of the Acrylic Bag Filter
Acrylic bag filters combine high hydrolysis resistance and acid compatibility with an economical cost structure. They are widely used in humid, acidic medium-temperature processes.
- High Hydrolysis Resistance
- In moisture-laden processes with condensation cycles, the fibre structure is largely preserved; works stably in applications where polyester bags degrade quickly.
- Acid and Chemical Resistance
- Good resistance to mineral and organic acids; stable filtration performance in processes where the flue gas chemistry fluctuates.
- Economical Cost Structure
- A clear cost advantage over PPS, P84 and PTFE; a cost-effective solution for processes that combine medium temperature and chemical challenges.
- Compatibility with Humid Environments
- Thanks to its low moisture absorption, the felt swells less; dimensional stability is maintained through high humidity and condensation cycles.
- Wide Range of Surface Treatments
- Calendering and Singeing
- PTFE Coating
- ePTFE Membrane Lamination
- Low Differential Pressure
- The dense needle-punched felt structure, together with high air permeability, gives a stable, low ΔP profile and keeps energy consumption low.
- Cleaning System Compatibility
- Compatible with all standard cleaning systems (pulse-jet, reverse air, shaker).
- Antistatic Option
- Can be given antistatic properties by integrating conductive fibres; a suitable option for applications with a risk of explosion.
- Resistance to Acidic Condensation and Corrosion in Stacks
- Protects the fibre structure against sulphurous acid condensation in boiler and flue gases, reducing the risk of early puncturing and rotting.
Engineer's Note
- Senior Process Engineer
- 15+ Years of Field Experience
- Field-Test Approved
The most common problem we see in the field with acrylic bag filters is the flue gas temperature exceeding the continuous operating limit through sudden rises. In that case fibre strength drops and bags need replacing earlier than expected.
When to choose it: in processes operating at 100–130 °C that contain moisture and acid components and where polyester cannot withstand hydrolysis, acrylic offers economical and reliable performance.
When not to choose it: in processes requiring continuous operation above 150 °C and in strong alkaline environments, Nomex, PPS or PTFE fibre media should be considered instead of acrylic.
Application and Selection Criteria
- Collar Type and Flange Fit
- Choose the bag collar (snap band, clamped, flanged or corded) according to the tube sheet hole diameter and the cleaning system; confirm the size and collar type before ordering.
- Temperature Limit
- Monitor flue gas temperature continuously; install temperature monitoring that raises an alarm when limit values are approached.
- Cage Check
- Check the filter cage when changing bags; a deformed or rusted cage can cause early failure of the new bag.
Collar Types and Connections
Safe, leak-tight seating of the dust bag in the tube sheet starts with the right collar type. Snap band, clamped, flanged and corded collar options are chosen according to the tube sheet design of your filter unit and the pulse-jet cleaning system.
Clamped Collar
Connection tightened onto the pipe collar with a stainless hose clamp.
Flanged Collar
Reinforced collar clamped by a venturi or top hold-down flange.
Corded / Beaded Collar
Leak-tight construction held in the seat by a corded seam.
Snap Band (Snap Ring)
Leak-tight snap-in system that seats in the tube sheet with a flexible steel strip.
Industry Applications
Bag filters suited to different process needs are used across a wide range of industrial applications to protect product quality, protect equipment and support production continuity.
01
Vegetable Oil
Clarity, purity and shelf life in vegetable oil and refining.
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02
Pipe and Profile
Cooling water filtration in pipe and profile extrusion.
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03
Paint Industry
Surface quality and pigment filtration in the paint industry.
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04
Glass Industry
Furnace and process filtration in the glass industry.
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05
Dialysis Centers
Water preparation and process filtration in dialysis centers.
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06
Foundry Industry
Equipment protection and dust filtration in foundries.
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07
Industrial Oil
Filtration in industrial oil production and recovery.
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08
Energy and Biogas
Maximum efficiency and turbine protection in energy and biogas.
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09
Recycling
Filtration for efficiency and environmental compliance in recycling.
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10
Food and Beverage
Hygienic filtration in food and beverage.
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11
Pharmaceuticals and Biotechnology
GMP-compliant sterile filtration in pharmaceuticals and biotechnology.
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12
Paper and Packaging
Process water filtration in paper and packaging.
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13
Chemical Industry
Corrosion-resistant, safe filtration in the chemical industry.
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14
Cosmetics
Microbiological safety and precision filtration in cosmetics.
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15
Machinery
Precision and technical filtration in the machinery industry.
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16
Printing and Ink
Flawless color and print quality in printing and ink.
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17
Metal and Surface Treatment
Flawless surfaces and bath stability in metal and surface treatment.
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18
Forest Products
Resin and glue filtration in forest products and furniture.
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19
Automotive
Precision process filtration for zero defects in automotive manufacturing.
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20
Oil and Petrochemicals
Equipment protection and process safety in oil and petrochemicals.
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21
Plastic Packaging
Precision process filtration and raw material purity in plastic packaging.
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22
Plastic Injection Molding
Cooling and hydraulic filtration in plastic injection molding.
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23
Water and Environment
Recovery filtration in water and environmental technologies.
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24
Shipyards and Marine
Operational safety and efficiency in shipyards and marine.
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Performance Parameters
The performance of acrylic felt bag filters is directly related to the media’s hydrolysis resistance and dimensional stability, especially under humid, hot process conditions. With the right surface treatment and filter construction, high dust retention efficiency is maintained while differential pressure rise and maintenance frequency are kept under control.
- Emission Value
- Standard acrylic felt media provide high efficiency in general industrial dust filtration. With a PTFE membrane surface treatment, low emission values are achieved for fine particles including PM2.5, making it easier to comply with strict emission limits.
- Service Life
- Thanks to high hydrolysis resistance and low moisture absorption, a longer service life is achieved in humid processes than with polyester bags. Choosing the right surface treatment and staying within temperature limits significantly extends service life.
- Differential Pressure
- The dense needle-punched felt structure and low moisture absorption stop the felt from swelling and narrowing its pores in humid processes. Differential pressure therefore stays stable close to its initial value, and system fan load and energy consumption are reduced.
Filter Selection Technical Checklist
- Gas Temperature
- Suitable for 100–130 °C; above 150 °C, Nomex or PPS should be considered.
- Alkaline Environment
- Moderate resistance to strong alkalis; for gases with high alkali content, PPS or PTFE should be considered.
- Humidity / Water Vapour
- Resistant to high humidity and condensation cycles.
- Chemical Environment
- Good resistance to mineral and organic acids; in strong alkaline environments, Nomex or PTFE should be considered.
- Emission Limit
- For processes with strict emission limits, an ePTFE membrane surface treatment should be chosen.
- Cleaning System
- Compatible with pulse-jet, reverse-air and shaker systems.
- Sticky / Oily Dust
- A water- and oil-repellent PTFE coating or an ePTFE membrane surface treatment should be chosen.
- Explosion / Static Risk
- Antistatic properties can be added by integrating conductive fibres.
Points to Watch When Using Acrylic Bag Filters
Key points to watch in operation and maintenance to preserve the hydrolysis resistance and high retention performance of acrylic bag filters:
- Gradual Start-Up
- At first start-up, raise the flue gas temperature in a controlled, gradual way; avoid sudden temperature changes and prevent the risk of thermal shock.
- Storage and Moisture Protection
- Use moisture-proof packaging in storage; do not place loads on the bags, and store them carefully in dry, suitable conditions so they are not damaged.
- Operating Temperature Limit
- Flue gas temperature must not exceed 130 °C continuously or 150 °C momentarily. Monitor temperature regularly, raise an alarm at critical levels and stop the system.
- Pulse-Jet Cleaning Pressure
- Keep the pulse-jet cleaning pressure within the recommended operating range; check pressure values regularly so that excessive pressure does not damage the felt structure.
- Dew Point Control
- Flue gas temperature must not fall below the acid dew point; otherwise condensing acid can make the dust cake stick and clog the bag surface.
- Cage and Support Check
- Check cages carefully when changing bags; do not use bent or damaged cages, and replace them when necessary so they do not damage the bag.
- Sticky Dust and Surface Treatment
- In processes with sticky dust, oil or moisture, choose PTFE-coated or membrane bags and monitor pressure loss and filtration.
- Explosion and ATEX Safety
- Standard acrylic bags are not suitable for processes with a risk of explosion or fire; use the antistatic version with conductive fibres.
Alternative media for the same application
Acrylic Bag Filter
Your Questions Answered
Frequently Asked Questions
At Prosestim, we are committed to answering your questions and providing technical support for our filtration solutions.
What is an acrylic bag filter?
It is a medium-temperature dust filtration medium made from homopolymer acrylic fibre by the needle-punched felt method. With a continuous operating temperature of 130 °C, high hydrolysis resistance and acid compatibility, it is an economical option for humid and acidic processes.
Why choose acrylic instead of polyester?
Up to what temperature can it withstand?
Acrylic bag filters withstand 130 °C continuously and 150 °C peaks. For continuous operation above 150 °C, Nomex or PPS should be considered.
Can it be used in strong alkaline environments?
Acrylic has moderate resistance to strong alkalis. For flue gases with high alkali content, PPS or PTFE bag filters should be considered.
Can it be used in humid processes?
Which surface treatment should be chosen for processes with sticky and oily dust?
Which cleaning systems is it compatible with?
Compatible with pulse-jet, reverse-air and shaker dust collector systems.
What is the main difference between acrylic and PPS?
Do you manufacture custom sizes?
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