| 摘要 |
PROBLEM TO BE SOLVED: To enhance reliability on a product by miniaturizing a refrigerant container for forming ice plugs through improvement of pressure resistance of ice plugs, in a method of improving residual stress with expansion of piping through external cooling of the piping, and by improving residual stress of small diameter piping in which sufficient temperature difference is hard to get because of a thin thickness, in a method of improving residual stress with impartation of temperature difference to the inner/outer face of piping. SOLUTION: In a method of improving residual stress by expanding piping through external cooling of the piping, a cooling speed in the formation of ice plugs is lowered in the center of a refrigerant container by partially insulating heat in the center of the refrigerant container, and thereby solidifying the ice plug center last. Also, in a method of improving residual stress by imparting temperature difference to the inner/outer face of piping, a tension load in the axial direction is imparted when the temperature difference to the inner/outer face is imparted. COPYRIGHT: (C)2009,JPO&INPIT |
