| 摘要 |
In a pipe which is used as a flow passage of a fluid, the present invention relates to a technology for forming a plurality of protrusions arranged at fixed intervals in a body of the pipe or a plurality of concave grooves (凹) arranged at fixed intervals on an outer part of the body, in order to prevent a situation where the pipe is broken by not being able to endure the pressure as the fluid filling the pipe is frozen and the pipe is expanded when the outside temperature falls below zero. |
