SUPERCRITICAL CRYOGENIC SELF CONTAINED BREATHING APPARATUS

A SELF-CONTAINED BREATHING APPARATUS (SCBA) CAN BE DESIGNED WHICH CAN USE LIQUID AIR FOR FILLING, OPERATE AT AMBIENT CONDITIONS OR UNDER WATER, BE ATTITUDE INDEPENDENT, AND CAN BE STORED WITH NO ENRICHMENT IN OXYGEN. BY USE OF THE PROPER DESIGN CRITERIA IT WILL MEET OSHA AND NISOH REQUIREMENTS. THE TECHNOLOGY REQUIRED TO MAKE THIS SCBA IS FAMILIAR TO THESPACE PROGRAM. THIS IS THE USE OF A SUPERCRITICAL CRYOGENIC FLUID IN PLACE OF A TWO-PHASE LIQUID-VAPOR SYSTEM. THE SUPERCRITICAL FLUID AIR WILL BE STORED AT ABOUT750 PSIA (50 ATMS) WHICH IS WELL ABOVE THE CRITICAL PRESSUREFOR AIR (37 ATM). IN THIS CONDITION THE SINGLE PHASE AIR IS AVAILABLE AT A SINGLE FIXED OUTLET IN ANY TANK ATTITUDE. EXCEPT FOR A SLIGHT POSSIBILITY OF STRATIFICATIONWHICH WILL BE INVESTIGATED IN PHASE I, THERE WILL BE NO SELECTIVE VENTING OF THE NITROGEN AS WITH TWO-PHASE LIQUID AIR. PHASE I OF THE EFFORT WILL INVESTIGATE THE FLUID PROPERTIES,THE SCBA WEIGHT AND VOLUME REQUIREMENTS, THE SYSTEM OPERATION, AND THE REFILL SYSTEM. PHASE II WILL DESIGN AND PRODUCE AN OPERATING SYSTEM. PHASE III WOULD GO INTO PRODUCTION OF THE SYSTEM FOR NASA AND OTHER EMERGENCY SERVICES UNITS.