guard cylinder

• 护筒

guard cylinder的用法和样例：

例句

1. But when holing in a certain height that the maximum mud height is less than the minimum mud height, take the cylinder to project the hole.
   当钻进到某一高程，桩孔中所要求的泥浆最大深度小于最小深度要求时，建议采取护筒护壁措施。