Industrial contaminated-air control is most reliable when every stage is designed as part of one system. A powerful fan or a high-capacity filter cannot compensate for an unsuitable capture point, an unbalanced duct network or an impractical material-discharge arrangement.
The engineering sequence begins at the emission source and follows the air path through transport, separation, filtration, air movement and safe discharge. Controls and risk-reduction measures connect these stages into a stable installation.
1. Capture the contaminant at its source
The capture device may be a machine connection, hood, extraction arm, downdraft bench, extraction wall or enclosure. Its position and geometry are based on how dust, fumes, mist or overspray leave the process. Close capture reduces dispersion and generally requires less air than attempting to clean the entire room after contamination has spread.
2. Transport air and material through the duct network
Circular ductwork, flexible connections, branches, bends and transitions are selected for the required airflow and pressure loss. Transport velocity must be appropriate for the material: insufficient velocity can allow deposits to form, while excessive velocity can increase energy use, noise and wear.
Manual or controlled slide gates can isolate inactive branches. Their operating logic should match the machines in use so that opening one branch does not remove the airflow needed elsewhere.
3. Reduce the load with pre-separation
For processes that generate chips, coarse particles or a high dust load, a cyclone or other separator can remove heavier material before final filtration. Pre-separation protects the filter, reduces cleaning demand and provides a practical route for collected material. The selected discharge method may include a container, rotary valve, screw conveyor or another arrangement suited to the production volume.
4. Select filtration for the contaminant
Bag and cartridge filters are used for suitable dry-dust applications, with pulse-jet cleaning available where the duty cycle requires automatic filter cleaning. Oil mist, paint overspray and vapours need dedicated technologies rather than a generic dust filter. Treatment may therefore include NO MIST or electrostatic equipment, Paint Stop or labyrinth filters, water-based stages, or activated carbon where adsorption is suitable for the identified compounds.
5. Match the fan to the complete network
The fan is selected for both airflow and total system resistance at the intended operating point. Filter loading, simultaneous branch use, duct losses and discharge conditions all affect that point. The design should also consider noise, access for inspection, drive arrangement and any process-specific material-handling requirements.
6. Balance extracted and replacement air
Air removed from a building must be replaced. Uncontrolled negative pressure can reduce extraction performance and create uncomfortable draughts. A coordinated solution may include grilles, make-up air, air-handling units or heating equipment, depending on the facility and process conditions.
7. Integrate controls and safety measures
Controls can start extraction with the process, operate filter cleaning, manage gates and report abnormal pressure or equipment status. If the risk assessment identifies combustible dust, sparks, hot particles or flammable vapours, the installation may also require detection, extinguishing, explosion relief, isolation or other protective measures appropriate to that risk.
Commission and maintain the system
Commissioning verifies airflow, pressure, branch balance, filter operation and control sequences under normal production conditions. Recorded baseline values support later maintenance. Routine checks should cover capture points, duct integrity, filter pressure drop, fan condition, gates, collection equipment and safety devices.
ALWO integrates equipment across this complete air path. Browse our contaminated-air capture and filtration range or discuss your application with the ALWO team.
