12 burners on a malt drying oven generated 95dB(A) with an 82Hz combustion generated “boom” as the dominant component. This was not only a very annoying occupational noise hazard, but also a potential environmental noise issue.
An acoustic enclosure was being considered, but was deemed too costly and too impractical. Building modifications were also under consideration, but were prohibitively expensive. The company contacted us to see if there was an alternative noise reduction technology. We diagnosed an organ pipe resonance caused by combustion mixture problems that caused pulsing of the flame front that excited the resonance. We solved the problem by sourcing and modifying off-the-shelf weld extract motor-controlled valves that were used to control the flame dynamics.
This provided a 21dB noise reduction at source for less than the cost of a single acoustic door…
