A new wet scrubber plant had generated noise complaints from local residents. Conventional silencers were considered, but fitting mufflers to scrubber fans is generally not a good idea...
- the environment can be corrosive, causing longevity and maintenance issues
- wet silencers will clog, requiring regular cleaning or replacement to maintain performance
- scrubber fan noise issues are usually caused by low-frequency tones (hum) for which conventional silencers are ineffective
Fortunately, there is an innovative alternative.
Scrubber noise diagnosis
Analysis of video clips forwarded by the client showed that the complaints were due to a classic low-frequency blade pass drone at 176Hz (8 blades, 1320rpm) as shown in this narrow band plot. This including a clip taken by the complainant in the bedroom, the location where they found the noise most disturbing. More detailed description of this diagnostic process.
Fan hum permanently eliminated
The solution was to design an aerodynamic insert that was fitted inside the fan casing. This cut the tone by around 98% (17dB), completely and permanently eliminating the problem for the lifetime of the fan without maintenance.
