| 摘要 |
Novelty: the invention relates to wavy tubes of double-layered wall for use, chiefly, in underground networks. Purpose: to provide protection against solar infra-red radiation and so prevent the downgrade of the outdoor-stored tubes quality, prior and after installation of same. Advantages: deterrence of rodents from damaging the tube and causing, thus, problems to the installation; easy traction of cables throughout their emplacement phase due to the inner layer of the tube being designed to exhibit low friction coefficient. All these advantages are obtained thanks to related additives added into the recipe of the two-layer material. Embodiment: the design of said tube is particularly suitable for application in subground electric networks as it covers three basic weaknesses habitually shown by ordinary tubes. |
