| 摘要 |
<p>The top section (22) of the aerator (10) membrane (14) is designed to form an axial fold (20) when the air supply is shut off. In this condition it is subjected to the hydrostatic pressure exerted by the water. The fold is in a zone free of aeration slit perforations. Preferred features: A longitudinal zone (32) of the membrane (14) has a radius of curvature impressed into it. This radius is smaller than the mean installed radius of the membrane. When installed, the membrane surrounds an introduced body (12). The impression forms an outwardly-directed bulge line. The curvature is alternatively formed by a longitudinal projection from the surface of the pipe insert, which may be formed integrally with it or is a separate component. The longitudinal projection is fastened onto, or forms an integral part of, the inner surface of the membrane. In a further variant, the pipe includes an indented longitudinal groove.</p> |
