Top Five Noise Control Techniques
Noise control is a burning problem, both in industry as well as at home. A few established techniques are listed in this article to inform or refresh the reader's inherent knowledge and desires at controlling this important health hazard! Having a wide application across the entire industrial sector, these 5 simple noise control techniques will produce substantial noise reduction with hardly any effect on normal operation of the equipment. The techniques are quite economical to implement and completely practical.Damping Control to Diminish Noise
Typical applications include Chutes, hoppers, machine guards, panels, conveyors, tanks, etc.
There are basically two techniques:
-"Unconstrained Damping" using bitumen based surface adhering layer
-"Constrained Damping" using a specially constructed laminate layer
Laminate damping is more effective and longer lasting. Either recycled steel (or aluminum) guards, panels and other components from commercially available sound muffled steel, or self adhesive steel sheet can be used. The latter can simply be adhered on both sides to achieve a reduction in sound transmission of nearly 5 to 25 dB. The layer covers around 80% of the area but it should be noted that the layer treatment thickness must be between 50 to 100% of the object thickness.
It should however be noted that above 3mm laminate sheet thickness, the efficiency of sound absorption becomes less and consequently the sound reduction level decreases.
Fan Installations and Noise Control
Typical applications include Axial flow or centrifugal fans.
Technique:
Maximum fan efficiency is indicated by minimum noise. Reduction in fan efficiency results in increased level of noise. Employing the proper combination of 'air flow principle' and using sound principle of designing fans, one can achieve nearly 3 to 10 dB reduction in the noise level.
Ductwork for Noise Control
Typical applications include extraction, cooling, and ventilation.
Technique:
The probability of achieving a 10 to 20 dB reduction in air borne noise is evident by lining the duct with acoustic absorbent material. This is more effective than fitting silencers to the system!
Alternatively, constructing bends with absorbent material lining to fit on the opening also achieves the desired result. Ideally, duct bends need lining on either side for at least a length of two times its diameter. For high air flow velocity one can also consider using cloth faced absorbents.
Difference In Chain And Timing Belt Drives For Noise Control
Technique:
Noisy chain or belt drives can be a nuisance at work places and should be replaced with the more efficient and more silent timing belts. Different types of timing belts are commercially available. Depending on the tooth profile, a range of sound reduction levels can be achieved. The latest "Chevron Tooth" pattern timing belts offer maximum noise reduction and are extremely efficient. Reduction in noise at a level between 6 to 20 dB is often feasible using these approach.
Electrical Motors and Noise Control Technique:
Most companies have a large numbers of electric motors widely used for fans, pumps and machine tools. Moreover, general duty motors exhibiting a quieter characteristic are available and they can reduce the noise level by as much as 10dBA at no extra premium.The best proposition is to slowly replace these motors over a time span to ensure that all motors conform to an acceptable noise control norm.
About the Author
Hemant Mehta is an elderly freelancer who made his passion for writing a profession!