| abstract |
A cryogenic fluid Dewar container (10) for supplying a gas mixture to an on-demand external delivery device, such as a regulator and associated facepiece (84) independent of the direction of its gravitational field and spatial orientation of the container, is described. The Dewar container holds a volume of cryogenic fluid (24) as a liquefied-gas at a relatively low pressure. A first endothermic heat energy conduction means (58) is mounted outside the Dewar and vaporizes and warms the cryogenic fluid to form a raised-energy fluid that is moved to an exothermic heat energy conduction means (62) mounted inside the Dewar container, which conducts a portion of the added heat energy to the remaining cryogenic fluid. This causes some of the cryogenic fluid to vaporize and raise the pressure inside the Dewar container. The somewhat re-cooled gas flowing through the exothermic heat energy conduction means moves to a second endothermic heat energy conduction means (80) mounted outside the Dewar, which rewarms the gas to about the ambient temperature before delivering the gas to the on-demand facepiece. An economizer valve (88) is provided to move the liquid and/or gas held inside the inner shell directly to the second endothermic heat energy conduction means when the internal pressure exceeds a predetermined level. In addition, the cryogenic fluid Dewar container of the present invention can be provided inside a cool hostile environment body suit (S) to provide an internal cooling system that freezes some of the humidity inside the suit created by prespiration. |