Keep proper length of pipe when put into the manhole .
布放后应保留适当长度于引进端人（手）孔或拉箱内。
Two alternative methods can be adopted, one being to provide a ventilation pipe fixed to a building and carded above the eaves level, and the other to have ventilated manhole covers.
有两种解决办法，一种是安装固定在建筑物上高度超过屋檐的通气管，另一个使用通风检查井盖。
Main products include ductile manhole covers, composite resin covers, drill rod cement covers, galvanized steel grating, polymer alloy covers, cast iron manhole covers, flower bar, cast iron pipe.
主营产品有球墨井盖、复合树脂井盖、钢钎水泥井盖、镀锌钢格板、合金高分子井盖、球墨铸铁井盖、铸铁井盖、花栏、铸铁管等。
应用推荐