Glass Fibre Bag Filter
260 °C Continuous Operation, Emissions Below 10 mg/Nm³ with ePTFE Membrane
The glass fibre bag filter is a filter medium made in woven and needle-punched felt constructions, available with an ePTFE membrane, for high-temperature flue gas and industrial dust collection systems operating continuously up to 260 °C.
770 g/m²
0.9 mm
260 °C
288 °C
What Is a Glass Fibre Bag Filter?
Glass fibre bag filters are a high-performance dust filtration medium made by processing alkali-free glass fibre yarn, melted and drawn at 1300–1600 °C, on special looms. Thanks to their inorganic fibre structure, they keep their dimensional and mechanical stability at high temperatures (260 °C continuous, 288 °C peak) where organic polymers are limited. Glass fibre bags used in dust collectors (baghouses) are compatible with pulse-jet, reverse-air and shaker cleaning systems.
The most important property of glass fibre is its suitability for demanding temperature and chemical environments such as cement clinker coolers, coal-fired boilers, metallurgical furnaces and waste incineration plants. The surface treatments applied to standard glass fibre woven media (ePTFE membrane, PTFE coating, silicone/graphite, acid-resistant coating) have a decisive effect on filtration efficiency, chemical resistance and dust release.
Product Identity and Technical Summary
Prosestim glass fibre bag filters are made from alkali-free E-glass woven and needle-punched felt media with a weight of 770 g/m² and a thickness of 0.9 mm. An ePTFE membrane is applied as the standard surface treatment, giving emission values below 10 mg/Nm³ for fine particles including PM2.5. A longitudinal tensile strength of 4,000 N/50 mm and a longitudinal elongation of 0.5% keep the bag intact under high mechanical stress. Service life exceeds 4,500 hours.
Key Technical and Structural Features
- Fibre Type
- Alkali-Free Glass Fibre (E-Glass)
- Fabric Structure
- Woven E-Glass
- Needle-Punched Felt (Nonwoven)
- Weight
- 770 g/m²
- Thickness
- 0.9 mm
- Air Permeability
- 25 L/dm²·min @ 200 Pa
- Continuous Operating Temperature
- 260 °C (Dry)
- Peak (Surge) Temperature
- 288 °C (Dry)
- Chemical Resistance
- Good resistance to acids; not suitable for HF and strong alkalis (pH > 10).
- Emission Performance
- < 10 mg/Nm³ (with ePTFE membrane)
- Service Life
- > 4,500 hours
Filtration Architecture and Working Principle
Glass fibre bag filters pass dirty flue gas or dust-laden industrial air from the inside of the bag to the outside in a two-stage treatment process. Dust cake management and the cleaning cycle keep the system working efficiently and the differential pressure stable.
Filtration takes place inside-out. Dust-laden gas fills the bag; particles are retained on the ePTFE membrane surface and in the glass fibre media, and the cleaned gas passes out through the fibre structure and leaves the system. The ePTFE membrane surface treatment stops particles penetrating into the depth of the fibres so that the dust cake forms on the inner surface of the media; this allows the dust cake to be removed completely during the cleaning cycle and keeps differential pressure low.
Dust Cake Formation
Dust-laden gas fills the bag and meets the inner surface of the ePTFE membrane. Particles build up on the membrane surface to form a dust cake and cannot penetrate into the fibres. This surface filtration mechanism retains even fine particles including PM2.5 effectively.
Cleaning Cycle
The dust cake building up inside the bag gradually grows and differential pressure rises. When the set ΔP threshold is reached, the cleaning cycle starts. The dust cake is detached from the inner surface and falls into the hopper by a short, high-pressure air pulse from outside the bag in pulse-jet systems, by reverse airflow in reverse-air systems, and by mechanical vibration in shaker systems.
Glass Fibre Bag Filter Surface Treatment Options
| Surface Finish | Property | Recommended Application |
|---|---|---|
| ePTFE Membrane (Standard) | Surface filtration, PM2.5 retention, < 10 mg/Nm³ emissions, effective dust release, chemical resistance | Waste incineration, chemical plants and all applications requiring precise emission control |
| PTFE Coating | Fibre surface encapsulation, abrasion protection, moderate chemical resistance, pulse-jet compatible | Coal boilers, general industrial applications |
| Silicone + Graphite + PTFE (SGP) | Abrasion protection, improved dust release, limited chemical protection, low cost | Cement plants, metal casting |
| Acid-Resistant Coating (AR) | Protection against acid dew point corrosion, strong resistance in SO₂/SO₃ environments | Fossil fuel power plants, carbon black production |
Engineer's Note
- Senior Process Engineer
- 15+ Years of Field Experience
- Field-Test Approved
The most common problem we see in the field with glass fibre bag filters is mechanical breakage of the glass fibres caused by excessively high-pressure pulse-jet cleaning or unsuitable cage tolerances (mechanical fatigue / flex fatigue). Although glass fibre has excellent temperature resistance, its resistance to mechanical flexing and friction is lower than that of polymer fibres; fibre cracking can occur under aggressive shaking.
When It Is Preferred
It is a solution that stands out with its non-flammable structure and dimensional stability in steel arc furnaces, foundries, ferroalloy plants, power plants and cement clinker cooling lines operating at extremely high temperatures of 200 °C to 260 °C (288 °C momentarily).
When It Is Not Preferred
On chemical lines where the gas stream contains HF (hydrofluoric acid) or heavy fluoride compounds, glass fibre dissolves quickly. Also, in uncontrolled cleaning systems with very high mechanical shock and abrasion, PTFE-coated composite alternatives should be considered instead of pure glass fibre.
Application and Selection Criteria
- Collar Type Compatibility
- Choose the collar type based on a photo or sample of your current filter; relying on catalogue dimensions alone is not enough.
- Temperature Limit
- Gas temperature must not exceed the 260 °C continuous and 288 °C peak limits; temperature monitoring is mandatory.
- Moisture and Chemical Compatibility
- With gases containing high humidity, condensation or HF, do not put into service without confirming the choice of ePTFE membrane or acid-resistant coating.
Collar Types and Adapters
Steel Ring (Snap Ring)
Galvanised or stainless steel ring. The most widely used, economical standard collar.
Drawstring
Can be tied manually to any pipe outlet or special hanger with the drawstring.
Plain Top
Has no ring; suitable for machines with a special clamping device.
Snap Ring (Snap Band)
The flexible steel band clicks into its seat. Allows fast change-outs.
Performance Parameters
The field performance of glass fibre bag filters is assessed on dimensional stability at a continuous operating temperature of 260 °C, emission efficiency of < 10 mg/Nm³ for sub-micron particles with an ePTFE membrane, and resistance to mechanical abrasion where the bag contacts the cage.
- Emission Value
- Standard glass fibre woven media provide high efficiency in general industrial dust filtration. With an ePTFE membrane surface treatment, emission values of < 10 mg/Nm³ are achieved for fine particles including PM2.5, meeting the requirements of strict environmental legislation.
- Service Life
- With the right surface treatment, suitable cage support (min. 20 vertical wires) and controlled operating conditions, a service life of more than 4,500 hours is expected. Sudden temperature fluctuations and excessive pulse-jet cleaning pressure significantly shorten service life.
- Differential Pressure / Energy Efficiency
- The surface filtration principle of the ePTFE membrane stops the dust cake penetrating into the depth of the fibres; after the cleaning cycle, differential pressure returns close to its initial value. This stable ΔP profile keeps system fan load and energy consumption low.
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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Filter Selection Technical Checklist
The wrong filter choice means early clogging, system failure and unnecessary cost. Choosing the right glass fibre bag filter requires eight critical parameters to be considered together, from gas temperature to chemical composition and from humidity to dust load. The checklist below is designed to help you make a fast, reliable choice on site and in technical discussions.
- Gas Temperature
- Suitable for continuous operation at 200–260 °C; tolerates short excursions above 260 °C up to 288 °C.
- Chemical Environment
- Resistant to acids; not suitable for HF and strong alkalis (pH > 10).
- Humidity / Water Vapour
- In high-humidity environments, an ePTFE membrane or special surface coating should be used.
- Emission Limit
- Provides emission performance of < 10 mg/Nm³ with an ePTFE membrane; suitable for retaining PM2.5 particles.
- Cleaning System
- Compatible with pulse-jet (0.3–0.5 MPa), reverse-air and shaker systems.
- Cage Support
- A cage with at least 20 vertical wires must be used; use with cages with fewer wires is not recommended.
- Abrasion
- Flex abrasion resistance is low; keep vibration and mechanical stress to a minimum.
- Connection Type
- Can be made to custom sizes with snap ring, flange or clamp connection options.
Points to Watch During Use
Whether glass fibre bag filters keep their mechanical integrity on high-temperature flue gas lines of up to 260 °C depends on the right cage choice, controlled pulse-jet pressure and management of temperature relative to the acid dew point. The operational checks below have been compiled to prevent mechanical brittleness and maximise bag life.
- 20-Wire Cage Support
- Do not put glass fibre bags into service without cage support with at least 20 vertical wires.
- Operating Temperature Limit
- Flue gas temperature must not exceed the 260 °C continuous and 288 °C peak limits; temperature monitoring is mandatory.
- Moisture and Condensation
- In processes with high humidity and water vapour, confirm the choice of ePTFE membrane or acid-resistant coating.
- Chemical Compatibility & HF Warning
- Glass fibre bag filters must not be used in processes and applications containing hydrofluoric acid (HF).
- Pulse-Jet Cleaning Pressure
- Keep the pulse-jet cleaning pressure within the recommended 0.3–0.5 MPa range; excessive pressure can cause fibre breakage.
- Storage and Moisture Protection
- Do not place loads on bags in storage, and use moisture-proof packaging.
Alternative media for the same application
Glass Fibre 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 a glass fibre bag filter?
Up to what temperature can it withstand?
What does an ePTFE membrane do?
It provides surface filtration on the bag surface; the dust cake does not penetrate into the fibres, is removed completely during the cleaning cycle, and emission values of < 10 mg/Nm³ are achieved.
Can it be used with gases containing hydrofluoric acid?
No. Glass fibre is not resistant to HF; PPS or PTFE fibre media should be chosen for these applications.
Why is a cage with at least 20 vertical wires required?
Can it be used in high-humidity processes?
What is the service life?
With the right surface treatment, suitable cage support and controlled operating conditions, a service life of more than 4,500 hours is expected.
What is the difference between glass fibre and Nomex (aramid)?
Nomex works up to 204 °C (continuous) and offers better flex abrasion resistance; glass fibre works up to 260 °C and provides higher acid resistance. Glass fibre is preferred when the temperature exceeds 204 °C or the acid content is high.
Do you manufacture custom sizes?
Yes, custom production is available in non-standard diameter, length and connection type combinations.
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