Baghouses
Reverse-air baghouse
Also known as reverse air baghouse, RA baghouse.
A reverse-air baghouse cleans its filter bags by isolating one compartment at a time from the main gas flow and forcing low-pressure clean air through the bags in the reverse direction. The reverse flow gently collapses the cake from the bag surface, which then falls into the hopper. Reverse-air design is common on coal-fired utility-boiler baghouses and on older industrial installations.
Strengths and weaknesses
| Strength | Weakness |
|---|---|
| Gentle cleaning extends bag life | Compartment must be offline during cleaning |
| Low compressed-air consumption | Requires a larger total bag area for the same duty |
| Tolerates long fibreglass bags | Slower cleaning cycle |
| Lower bag wear than pulse-jet | Cleaning intensity not easily varied |
Where sonic horns help
The gentle nature of reverse-air cleaning leaves residual cake that gradually accumulates over time. Sonic horns mounted at the compartment roof break up the residual cake without the bag wear of more aggressive primary cleaning, defer the need for offline manual cleaning and reduce average differential pressure.
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.
- 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.
- Compartment isolationCompartment isolation is the procedure of closing inlet and outlet dampers on one baghouse compartment so it can be cleaned or have bags replaced while the rest stays online.
- 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.