The invention is an inserting pipe used for insulated steam injection pipeline which insulates in the joint between the two double-deck pipe. The inserting pipe is installed into butt joint section of the pipe and covers the ends of these two pipe from inside. This inserting pipe is a double-deck device, between the pipe walls there is a interval and the ends is connected together. In the annular space between the double-deck walls, insulated material can be put. At the same time, the inserting pipe is connected with one of the pipes and keeps away with another so as to prevent steam from leaking. The steam can flow into the interval between the inserting pipe. At the pipe joint the steam condenses into water to form a thermal insulated medium. |