| 摘要 |
Two flexible, mechanically consolidated non-woven fabric webs, arranged at a distance from one another, and an intermediate layer, arranged between the non-woven fabric webs, of loosely arranged rigid expanded plastic particles are provided in a device for protecting drainage pipes. The non-woven fabric webs are advantageously designed as a flexible tube or as a pocket closed all round, the non-woven fabric consisting of polyester or polypropylene. The rigid expanded plastic particles arranged in the tube or pocket consist of polyethylene or polystyrene foam in a grain size of 7 to 30 mm.
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