SPIRAL WOUND ION EXCHANGE UNIT FOR THE PRODUCTION OF STERILE WATER FOR INJECTION

THE U.S. ARMY RESEARCH AND DEVELOPMENT COMMAND IS DEVELOPING A WATER TREATMENT SYSTEMM FOR THE PREPARATION OF U.S. PHARMACOPEIA (STERILE, PYROGEN-FREE) WATER FOR INJECTION FROM POTABLE WATER SOURCES IN A FIELD SETTING. ONE IMPORTANT COMPONENT OF THE SYSTEM IS AN ION EXCHANGE UNIT TO POLISH WATER TREATED BY REVERSE OSMOSIS. CONVENTIONAL ION EXCHANGE UNITS HAVE GEOMETRIC CONSTRAINTS THAT DO NOT MAKE THEM SUITABLE FOR FIELD USE. THIS PHASE I PROGRAM ADDRESSES THE DEVELOPMENT AND TETING OF A PROTOTYPE SYSTEM THAT WILL BE NO LONGER THAN A 12-OZ. BEVERAGE CAN, HAS AN EXCHANGE CAPACITY OF AT LEAST 1G AS SODIUM CHLORIDE, AND MUST PRODUCE WATER WITH A SPECIFIC RESISTANCE OF AT LEAST 1MOHM. THE UNIT MUST ALSO BE ABLE TO OPERATE IN ANY POSITION WITHOUT LOSS OF EXCHANGE CAPACITY DUE TO CHANNELING. THE DESIGN INVOLVES THE USE OF A SPIRAL GEOMETRY IN CONJUNCTION WITH A RELATIVELY NARROW DIAMETER BED TO OBTAIN A LONG BED LENGTH AND A HIGH CAPACITY WITHIN THE BEVERAGE CAN ENVELOPE. THE DESIGN ALSO INVOLVES THE USE OF A COMPRESSIVE FORCE TO DISTORT THE BED, TAKING UP THE EXCESS VOLUME AS THE RESIN CONTRACTS DURING SERVICE AND PREVENTING CHANNELING ALONG THE WALLS.