Tube bundle fix the drooped structures through welding for both ends of upper header and make fly ash drop by rapping the end plate of lowerheader.
锅炉中的管束是上部集箱的两端通过焊接固定垂下的结构，通过锤打下部集箱的端板，振落飞灰。
2
A multitude of ring-shaped cracks and three water leakage points were discovered in the right side lowerheader of a boiler together with a cave-in of the boiler roof water-cooled wall.
锅炉右下集箱产生了很多环状裂纹和三个渗水点，同时顶棚水冷壁管塌陷。
3
This means that routers strip off the Ethernet header upon reception of a packet, and then add a new lower layer header-ethernet or otherwise-when the packet is forwarded.