Keeping South African workplaces below occupational exposure limits and compliant with the Air Quality Act starts with a correctly sized baghouse. Here’s a concise, practical method Envirox uses on projects across SA
- Determine airflow (m³/h). List all pickup points and set transport velocities high enough to keep dust suspended. Light dust needs less, heavier particulate needs more. A common target is 18–25 m/s in branches. Calculate flow per point with Q = A × v (m³/s) and multiply by 3600 for m³/h. Add diversity factors if not all points run simultaneously.
- Estimate total static pressure. Add losses from hoods (entry loss), straight duct friction (Pa/m), fittings using loss coefficients or equivalent lengths, plus the baghouse’s operating differential pressure (typically reading across the filter) and spark arrestors, silencers, or pre‑separators if any. Sum in Pascals to size the fan’s pressure requirement.
- Size the ductwork. Choose diameters that maintain target velocities at design flow. Keep transitions below 15-degree divergence; use long‑radius elbows; avoid sharp reductions. Fit blast‑gates or dampers for balancing so velocities don’t collapse when points are closed.
- Check filter area (air‑to‑cloth). Air-to-cloth = airflow (m³/s) ÷ effective media area (m²). Select filtration velocity appropriate to dust and cleaning method: pulse‑jet units run higher air-to-cloth than reverse‑air or shaker. Staying within the recommended range keeps differential pressure stable and lengthens bag life.
Choosing the right Nederman filter with Envirox
Envirox, South Africa’s specialist in industrial air filtration and Nederman’s dedicated distributor, applies the above to select and commission the correct solution:
- LBP SmartFilter: versatile and scalable for continuous duty.
- LBR SmartFilter: modular for very large flows and bulk materials.
- Auto M: robust, simple for intermittent duty.
Speak to Envirox for on‑site measurement, fan curve verification, and compliance support tailored to the South African industry.
