| 摘要 |
The attenuator has a sleeve (1) mounted coaxially inside the outlet section of the chimney (2). The sleeve is perforated with holes (5) whose dimensions are adapted to the frequency of the noise to be damped. The holes in the sleeve are spaced at regular intervals and are square or rectangular in shape. The sleeve is made e.g. from carbon steel, stainless steel, a laminated material, high-density polypropylene or a glass fibre material. The dimensions of its holes, wall thickness, and the size of the gap between the sleeve and chimney are calculated for a given noise frequency. In a variant, a second coaxial sleeve with rounded ends can be located coaxially inside the main one. |
