| 摘要 |
<p>A frond line for filtering particulate material from currents flowing over a river or sea bed comprises a substantially continuous curtain of randomly overlapping elongate buoyant elements extending transversely in a common direction from a longitudinally folded web, the base of each element being gripped between the superposed portions of the folded web. A frond mat is produced by combining spaced parallel rows of the frond lines with spaced generally parallel cross-straps to provide an open grid mat structure. Anchoring straps depend from the mat, each strap carrying a ground anchor plate which is driven into the river or sea bed by a powered driving tool. The frond line is produced by laying discrete transverse strips of synthetic buoyant material along the web so that equal lengths extend from opposite sides of the web, folding the web longitudinally, and then securing the superposed portions of the web to one another.</p> |
