How do you calculate can velocity (housing free-area velocity)?
Can velocity is the upward passage speed of the dust-laden gas flow through the free housing area between bags. High can velocity causes dislodged dust to be re-entrained onto clean bags and causes local wear. This tool calculates the free area and can velocity from housing inner dimensions, bag diameter and count.
Formulas and method
Free housing area: A_free = W x D - N x pi x (dia/2)^2 [m^2], W, D, dia in meters
Can velocity: V_can = (Q / 3600) / A_free [m/s], Q real m^3/h
- Housing inner length/width (W x D, top view) is the gross cross-section area where the bags sit; the cross-section occupied by the bags is subtracted from it.
- Above 1.2 m/s can velocity, the risk of dislodged dust re-entraining onto bags rises; above 1.5 m/s this risk is significant.
- All calculations are performed using real gas conditions (operating temperature and pressure).
Frequently asked questions
Other calculators
This tool is for preliminary sizing and checking purposes. Results vary with dust load, particle distribution, moisture, temperature fluctuation and cleaning system performance. Final design and bag/cage selection should be verified with the Hantech Filter engineering team using real site data.