District heating pipes - Preinsulated bonded pipe systems for directly buried hot water networks - Joint assembly for steel service pipes, polyurethane thermal insulation and outer casing of polyethylene
区域供暖管道.直埋热水管网用预绝缘粘结管道系统.钢制供水管、聚氨酯隔热和聚乙烯外壳的接头组件