| 摘要 |
<p>PURPOSE:To suppress easily propagation of a crack in piping by fitting fastening members made of a shape memory alloy in the axial direction on the outer circumference of piping having the position of a minute crack not penetrating through the pipe walls by sandwiching the crack-position between the said members and joining together the members with bolts of a shape memory alloy and then heating the whole up to a specified temperature. CONSTITUTION:Fastening members 6,7 made of a shape memory alloy, two as a pair, are each divided into two halves on the plane including the central axis. The two halves are so formed that when assembled on the division plance a short cylindrical shape will be given with the outer and the inner circumference being on the identical axis. The cylinders 6,7 are each provided with eight through threaded holes 10 in the annular wall at equal pitches in parallel with the axis, and a bolt 9 made of the shape memory alloy, consisting of a screw part and a rod part, is inserted into the threaded hole 10. When the fastening members 6,7 are heated and thus the alloy returns to the state of a parent phase, the inside diameter of the fastening members 6,7 is recovered to the size memorized as the member of the parent phase. Consequent ly, the fastening device 1 tightens the piping 2. And the bolt 9 also tightens the fasten ing members 6,7 as a pair.</p> |
