Baghouses
Fabric filter
Also known as fabric filters, bag filter, dust collector (fabric).
A fabric filter is an air-pollution-control device that removes particulate from a gas stream by passing the gas through woven or felted fibre media — usually in the form of cylindrical filter bags — collecting dust as a cake on the bag surface and periodically releasing the cake into a hopper below. Fabric filters are the dominant particulate-control choice on cement plants, waste-to-energy plants, biomass boilers, metallurgical off-gas, food and chemical process exhaust.
Why fabric filters compete with ESPs
| Attribute | Fabric filter | ESP |
|---|---|---|
| Outlet particulate | < 5 mg/Nm³ typical, < 1 mg/Nm³ achievable | 10–30 mg/Nm³ typical |
| Insensitivity to dust resistivity | Yes | No (back-corona risk) |
| Energy consumption | Higher (ΔP overcomes filter resistance) | Lower (electrostatic field only) |
| Sensitivity to moisture / dew point | High | Lower |
| Footprint | Typically smaller | Typically larger |
Where sonic horns fit
Sonic horns installed on a baghouse supplement the primary cleaning system (pulse-jet, reverse-air or shaker) by reaching dust the primary cleaning misses, reducing differential pressure, extending bag life and dislodging cake bridging in hoppers below the bags.
Related terms
Related terms
- BaghouseA baghouse is the structural enclosure that holds the bags, cages, tubesheet, cleaning system and hoppers of a fabric-filter dust collector. Sized in compartments for online isolation.
- Pulse-jet baghouseA pulse-jet baghouse cleans bags with brief, high-pressure reverse-air pulses while staying on-line. The dominant industrial fabric-filter design for new installations.
- Reverse-air baghouseA reverse-air baghouse cleans bags by isolating a compartment and passing low-pressure clean air through the bags in the reverse direction. Common on coal-fired utility duty.
- Filter bagA filter bag is the cylindrical fabric sock that traps particulate inside a fabric filter. Media selection depends on temperature, gas chemistry, dust load and cleaning cycle.
- Sonic hornA sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.
- Differential pressure (baghouse)Differential pressure (ΔP) across a baghouse is the pressure drop between dirty and clean plenums. It is the headline operational KPI: too low signals broken bags, too high signals fouling.