METHOD AND APPARATUS FOR MAKING LIQUID NITROGEN INTO MICRO-DROPLETS, NOZZLE ASSEMBLY FOR THE APPARATUS, AND MANUFACTURE OF POSITIVE PRESSURE PACKAGE BY FILLING THE MICRO-DROPLETS OF LIQUID NITROGEN

摘要

PROBLEM TO BE SOLVED: To obtain a method for making liquid nitrogen into micro-droplets for stably making liquid nitrogen into micro-droplets thereby obtaining a low positive pressure gas substituted package excellent in quality assurance. ;SOLUTION: A liquid nitrogen reservoir heat-insulating tank 2 and a spray nozzle 15 having fine holes 19 coupled via a heat-insulating pipe are provided, liquid nitrogen is supplied by the heat-insulating pipe to an entrance of the fine holes 19 without vaporization, and the liquid nitrogen is passed through the fine holes 19 in a state of being liquid and discharged into an atmosphere toward a container head space. A part of the liquid nitrogen rapidly vaporizes and swells immediately after the liquid nitrogen passes through the fine holes 19, whereby remaining liquid nitrogen still in a liquid phase is made into micro- droplets and a container head space is filled with the micro-droplets of liquid nitrogen. In addition, the vicinity of exits of the fine holes 19 is covered by dry gas to prevent moisture contained in an atmosphere from freezing at a tip of a nozzle.;COPYRIGHT: (C)1999,JPO