Cement fan stack noise reduced over a weekend...
Unfortunately, the plant update to improve the efficiency of the exhaust fans in a large cement works created a serious noise problem that generated complaints from miles around. A novel, low-cost attenuation system was designed and fitted over a weekend to avoid the eye-watering downtime cost required to implement conventional solutions.
Conventional stack silencing would have resulted in an unacceptable delay in solving the problem. In addition, it would also have involved massive capital expenditure plus the costs of a very prolonged shut-down and the system efficiency would also have been reduced. Our alternative solution was based on designing a set of bespoke stack silencer elements tuned to suit the noise signature. These were pre-fabricated off-site and then inserted into the stack through a small access door over a weekend.
The result was a 19dB noise reduction over the critical low-frequency range with zero effect on the fan or stack efficiency. The overall cost was a small fraction of conventional silencing - and without the reduced fan efficiency.
The alternative to costly 19th century attenuators
Large centrifugal cement works fans are a common source of low-frequency (and tonal) noise problems. Where the tonal content is the dominant issue, our aerodynamic fan noise reduction technology is by far the best alternative to fundamentally 19th-century noise control techniques such as silencers, enclosures and lagging. These involve high capital expenditure and extensive downtime to fit with increased maintenance and running costs (due to reduced system efficiency).
Where it is not possible to achieve the desired result using aerodynamics, this new stack modification technology can (and has been) been fitted in a couple of days to cut the noise across a wide range of frequencies without the reduction in fan efficiency often associated with silencers.