A dust extraction system only works if the fan can move the required volume of air against the total resistance of the hoods, ducting, collector and stack. Get the fan wrong and nothing else in the system will perform as designed.
Airflow and pressure
The required airflow comes from the capture velocity needed at each hood and the transport velocity needed to keep dust moving in the ducting. The pressure comes from adding up the resistance of every component. Both figures are needed to select a fan.
Clean-air or dirty-air duty
Most fans are placed after the collector, where they handle clean air. Fans that handle dusty air need wear-resistant materials and blade designs that resist build-up.
Efficiency and control
A fan that runs close to its best efficiency point uses less energy and runs more quietly. Variable speed drives allow the airflow to be adjusted as filters load or as pickup points are opened and closed.
Common problems
- Fan undersized after the system was extended
- Wrong rotation after motor replacement
- Worn or unbalanced impeller
- Blocked or poorly designed ducting
SP&DE measures existing systems and selects fans to suit. Contact us if your extraction has lost suction.
