| 摘要 |
PURPOSE:To eliminate the gap of a coil caused by cooling contraction during molding process of a superconductive coil, by a method wherein the coil as a whole is cooled well by liquid nitrogen, and the coil is tightened by pressure applied to both ends. CONSTITUTION:A coil 1 as a whole is immersed in liquid N2 and cooled well, and at the temperature (about 77K) thermal contraction of the coil 1 is performed completely. In order to eliminate gap in the coil 1 as a whole, pressure is applied from both ends in arrow direction using a press and nuts 7 of tightening bolts 6 are tightened in constant torque using a tightening tool 3. In this constitution, thermal contraction of the superconductive coil caused by temperature difference during cooling work to a temperature in use is small and also the produced gap is small, thereby necessary pressure of the press becomes small. Since strain is not concentrated in specific section of the coil, damage given to the coil is reduced. Accordingly, gap caused by the cooling contraction of the coil can be adjusted to a small amount using lower pressure than in conventional method. |
