| 摘要 |
<p>PURPOSE:To use a pipe line in which a plurality of pipes are connected by joints, for a long time by turning pipes at suitable time intervals (every time when the wall thickness of the bottom part of a pipe is decreased by a predetermined value) so that the bottoms of the pipes are shifted upward. CONSTITUTION:In a pipe line in which hard vinyl chloride resin pipes 1, 1 are connected together by means of a hard vinyl chloride joint 2, at a stage such that the wall thickness of the bottom of the pipe a is more or less decreased by a fluid passing through the pipe line for a long time, A blind nut 23 on the joint 2 is loosened so as turn the pipes 1, 1 by an angle of 180deg. Accordingly, the bottom of each of the pipes 1 whose wall thickness is decreased, is located right above, and in this condition, the blind nut 23 is fastened to for refixing the pipes 1, 1. Accordingly, the pipe line can be used for a long time, and accordingly, this process is cheaper than the conventional process in which pipes are replaced with new ones.</p> |
