煤矿井下的抽放瓦斯管;
Underground coal mine drainage gas pipe;
煤矿井下的电力电缆、光缆通讯信号电缆的保护管;
The protection pipe of electric power cable and optical cable communication signal cable in coal mine;
煤矿井下压风和通风管道;
Pressure wind and ventilation pipe in coal mine;
高瓦斯或粉尘环境下的其他压力管道。
Other pressure pipes in a high gas or dust environment.