Baghouses
Tubesheet
Also known as tube sheet, bag sheet, cell plate.
The tubesheet is the perforated steel plate that separates the dirty-gas and clean-gas plenums inside a baghouse. Each hole in the tubesheet corresponds to one filter bag; the bag hangs below, sealed against the hole rim by a snap-band collar at its top.
Why tubesheet integrity is critical
The tubesheet is the structural and gas-tight boundary that prevents dirty flue gas from bypassing the bags entirely. Any failure of seal or perforation immediately admits unfiltered gas into the clean plenum and out of the stack as a particulate emission.
Failure modes include:
- Snap-band leakage — bag collar improperly seated or distorted
- Hole erosion — fly ash gradually wearing the perforation
- Tubesheet warping — thermal cycling on long, lightly-supported plates
- Bag-bottom collapse that lifts the snap-band from the tubesheet hole
Inspection access
The tubesheet is inspected from above (clean side) during outages, walking on plywood mats to avoid distorting it. Any leaking bag is identified by deposits on the tubesheet top side around the affected hole.
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.
- Bag cageA bag cage is the welded wire frame that holds a filter bag open against differential pressure inside a pulse-jet baghouse. Cage corrosion or breakage causes immediate bag collapse.
- PlenumA plenum is a gas-flow chamber inside a baghouse. The dirty plenum sits below the tubesheet; the clean plenum sits above. Their pressure difference is the headline ΔP.