Plug-weld the connection between the closing panel and the inner light housing under shielding gas.
用气体保护塞焊，焊接封闭板与内侧灯罩之间的接合处。
2
Pneumatic valve and plug valve of a type is the same, only it's shut down parts of a sphere, the sphere rotates around the body center line to achieve the opening and closing a valve.