An agile solution to powerloom noise mitigation
Background
Thousands of family- owned powerlooms operate out of houses in urban localities in Karnataka. These should'nt have been in the news except for the bothersome high levels of noise they generate in operation. So much that the Govt of Karnataka was compelled to address it on an emergent mode and sought a solution from my team. We were given just a couple of months to complete everything from understanding to delivering a solution, that is, an acoustic barrier that would dissipate energy across much of the noise spectrum.
Tests
Not too sure about the outcome, I and my team members started off with visits to some powerlooms across the city. Many brainstorming, meetings with textiles department officials and discussions followed. Finally it was a full- day of field measurements at a designated powerloom in Bengaluru south. Noise and accelerometer data were acquired through a 12 channel NI DAQ with 110 kHz sampling frequency while post- processing was done on Labview. The video clip below shows a sample of the noise generated by operation of the powerloom machine.
Frequency- time dB amplitude
Seen below is a frequency- time spectrum of a noise sample captured during operation of the powerloom. As the pic shows, much of the acoustic energy is contained around 3 kHz and 5 kHz. Across the horizontal time axis, the color strip- like character correlates with cycles of the shuttle's traverse, each cycle resulting in a strip.
An agile, simple, but effective solution!
After all the noise data had been processed, our design solution was due in only a few days! With that timeframe before us, I had no option to try any kind of rigorous optimization and had to instead propose a solution concept distilled from experience. Seen alongside is the rather simple enclosure solution that shrouded much of the source noise in the powerloom. A few other absorbent stand mounted pieces were employed as well, not pictured here. Fabrication was quick, thanks to a few highly motivated and skilled workers. From a full day of tests at various locations around the machine hall, the enclosure was seen doing its job well, yielding nearly a 32 dB drop between source (machine) and receiver (outside hall), on proper placement, as shown next.
Results
