Noise Levels of Lint Doffing Brushes

ABSTRACT FOUR gin stand doffing brushes were tested to determine the effect of brush design on sound generation, lint doffing ability, and pneumatic conveying of lint. The sound levels produced by two experi-mental brushes were 5 to 6 dBA less in the area behind the gin stand than that produced by brushes generally used in cotton gins. An experimental brush with long bristles in closely spaced spiral rows was the most effi-cient one for doffing and for inducing an air stream for pneumatic conveying of lint, and could consequently be operated at a slower speed. Operating at a slower speed reduced the sound level in the area behind the gin stand by an additional 5 dBA. The minimum brush speed for doffing and conveying of lint under good conditions was found to be about 50 to 60 percent of the speed at which the brushes were normally operated which shows that gin stands have only a relatively small reserve of excess doffing capabilty for meeting less than optimum operating conditions. Adoption of the long bristle brush design would result in a significant reduction in the sound level produced by doffing brushes in gin stands and would aid substantially in abatement of one source of noise which cotton gin employees are ex-posed to.