| 摘要 |
<p>A circular storage enclosure with a flat bottom has a central emptying point. radial shuttering (7) is arranged in the form of an isosceles triangle, in plan, and of trapezoidal form in elevation with the upper side sloping downwardly towards the centre of the enclosure. The shuttering defines two converging longitudinal passages (11, 12) extending inwardly from an outer peripheral passage (10). Gas is permitted to escape through openings (13) provided on the side faces of the shuttering. A stiffening and reinforcing portion (8) is provided within the shuttering.</p> |
