Glossary
Electrostatic precipitators
Turning vane
Also known as turning vanes, inlet vane, gas distribution vane.
Turning vanes are gas-distribution devices installed in the inlet plenum of an ESP — and sometimes in upstream duct elbows — to straighten and evenly distribute the flue gas before it enters the plate stack. Even gas distribution is critical to ESP performance: a poorly distributed flow leaves part of the collecting area under-used while overloading the rest.
Failure modes
- Vane fouling — ash builds up on the leading edge and disrupts the designed flow pattern
- Vane erosion — abrasive ash gradually thins the vane, especially on biomass and waste-to-energy duty
- Distortion — thermal cycling warps the vane and changes the deflection angle
- Detachment — vanes loosen and fall into the gas stream, blocking field inlets
Sonic horns on inlet ducting
Acoustic horns installed in the inlet plenum keep turning-vane surfaces and adjacent ducting walls clean, preserving the designed distribution. Without periodic cleaning, distribution drift can reduce overall ESP collection efficiency by several percentage points before the cause is identified.
Related terms
Related terms
- Electrostatic precipitatorAn ESP removes particulate from flue gas by charging dust and collecting it on plate electrodes. Sonic horns are widely used to dislodge ash from plates and to keep hoppers from bridging.
- SneakageSneakage is flue-gas flow that bypasses the active electrostatic field of an ESP, typically through hopper voids or above the plate stack. It directly reduces collection efficiency.
- Collection efficiencyCollection efficiency is the fraction of inlet particulate captured by an ESP, baghouse or cyclone. Reported as a percentage; modern ESPs achieve 99.5%+, baghouses 99.9%+.