Baghouses
Can velocity
Also known as upward can velocity, interstitial velocity.
Can velocity (also upward can velocity or interstitial velocity) is the upward gas velocity in the space between filter bags inside a baghouse compartment. It is calculated as the gas flow into the compartment divided by the open cross-sectional area between bags (compartment area minus bag-and-cage area).
Why it matters
Cake released from a bag during cleaning falls vertically into the hopper. If the upward can velocity is too high, the falling cake is re-entrained back up onto adjacent bags, defeating the cleaning cycle and raising differential pressure. Typical design limits:
| Cleaning system | Max can velocity |
|---|---|
| Pulse-jet | 1.5–2.5 m/s |
| Reverse-air | 0.6–1.0 m/s (compartment offline during cleaning, so the limit applies only between cleans) |
Relationship to A/C ratio
Can velocity rises with air-to-cloth ratio and falls with bag spacing. Designers tune both together: a high A/C only works if bag spacing is wide enough to keep can velocity in range.
Related terms
Related terms
- Air-to-cloth ratioAir-to-cloth ratio is the gas volumetric flow rate divided by total bag filtration area. It is the primary baghouse sizing parameter and a strong predictor of bag life and ΔP.
- 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.
- 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.