Aerotech Fans
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Aerotech Fans
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Engineering answers to the most common questions about industrial ventilation, air handling, and pollution control systems.
To neutralize Sulfur Dioxide (SO2) in a wet scrubber, the recirculating water is typically dosed with an alkaline reagent such as Sodium Hydroxide (Caustic Soda, NaOH) or Calcium Carbonate (Limestone), which reacts with the SO2 to form harmless aqueous salts.
Building Management Systems (BMS) typically trigger jet fans to activate at a low speed when Carbon Monoxide (CO) reaches 25 ppm, and ramp up to full emergency dilution speed when concentrations hit 35 to 50 ppm, ensuring safe breathable air without wasting continuous electricity.
Non-woven felted bags (like standard 16 oz polyester) are thick and provide high-efficiency depth filtration, making them standard for pulse-jet systems. Woven bags are thinner, rely strictly on the dust cake for filtration, and are used primarily in older mechanical shaker dust collectors.
Jet fan spacing is determined by the fan's throw distance and thrust rating. Typically, fans are spaced 15 to 25 meters apart in parallel rows, ensuring the aerodynamic throw profile of one fan successfully entrains air and hands it off to the intake zone of the subsequent fan.
A G4 filter is a pleated, primary coarse filter used at the intake of an AHU. It captures large particulate matter (like dust, pollen, and insects) with 90% arrestance, acting as a sacrificial shield to protect the expensive secondary F7 fine filters and the chilled water coils.
Blade Pass Frequency (BPF) is calculated by multiplying the fan's RPM by the number of impeller blades, then dividing by 60. Identifying the BPF is critical for acoustic engineers to design perfectly tuned cylindrical silencers that attenuate the exact tonal noise generated by the fan.
Commercial kitchen balancing requires the Make-Up Air (FAU) to supply roughly 80% to 90% of the air volume extracted by the exhaust fan. The remaining 10% to 20% deficit creates a slight negative pressure, ensuring food odors are kept inside the kitchen rather than drifting into the dining room.
A bleed-in (or dilution) damper is an automated safety valve installed upstream of a high-temperature baghouse. If the exhaust gas temperature spikes dangerously close to the melting point of the filter bags, the damper rapidly opens to draw in cool ambient air, quenching the gas stream instantly.
Instead of firing compressed air on a continuous timer, Pulse-on-Demand uses a differential pressure transmitter (like a Photohelic gauge). The PLC only fires the pulse-jet valves when the dust cake resistance crosses a specific threshold, drastically reducing compressed air consumption and extending filter bag life.
Because jet fans operate at extremely high discharge velocities to create thrust, they generate significant aerodynamic noise. Cylindrical silencers lined with acoustically transparent perforated metal and high-density mineral wool are mounted upstream and downstream to meet stringent urban Noise Criteria (NC).
For standard commercial cooking equipment, the exhaust hood must maintain a capture face velocity of 50 to 75 Feet Per Minute (FPM). For heavy-duty solid fuel or charbroiling, the velocity must be engineered closer to 100 FPM to ensure the thermal plume is completely captured.
To prevent severe system effect (aerodynamic turbulence that destroys fan efficiency), there must be a minimum of 2.5 to 3 duct diameters of straight, un-obstructed ductwork immediately following the discharge of a centrifugal blower before the first elbow or transition.
