A cryogenic fluid vaporizer using ambient air comprising a conduit through which the fluid is passed having an outer finned tubular sleeve which includes a thermal insulation barrier between the conduit and the outer finned tubular sleeve. A fan may be included to provide an increased rate of heat transfer from the air to the outer surface of the fins of the tubular sleeve. The combination of the externally finned area and the insulating thermal barrier prevents the information of ice or frost on the exterior surface of the fins during the transfer of heat from the ambient air to the cryogenic fluid providing a frost-free cryogenic ambient air vaporizer for continuous operation.
