Noise Reduction in Pneumatic Ducts That Convey Peanut Hulls
ABSTRACT NOISE measurements in peanut shelling plants revealed that pneumatic ducts that convey peanut hulls are a major source of noise. Noise was found to increase with air velocity and turbulence and to decrease with in-creased duct wall thickness. Numerous treatments were evaluated for their effectiveness in reducing noise. Covering the ducts with commonly available thermal insulation was the most effective treatment, considering cost and convenience. However, treat-ing the ducts with a mastic compound offered advantages and should be considered in some instances. Special acoustic materials were generally con-sidered to be too costly.