Acoustical Transmission Losses in Pneumatic Systems in Cotton Gins
ABSTRACT THE pneumatic conveyance of seed cotton through sheet-metal pipes in cotton ginning systems con-tributes strongly to the noise levels of the system. Numerous acoustical treatments were applied separately to a straight pipe and a 90-degree elbow inside an acoustical chamber. Sound-power levels were measured and transmission losses were calculated as seed cotton was conveyed through the system. A rubber-lined elbow covered with a 10.2-cm layer of fiber glass and a layer of lead produced the highest transmission loss. However, all of the acoustical treatments significantly lowered the sound-power level of the standard elbow. Selection of the optimum solution for a particular application depends primarily on the degree of noise reduction required and the cost of the acoustical treatment.