Controlled-atmosphere technology for shipment of perishables
Carrier Transicold, Atlanta, developed the next-generation EverFRESH system, which uses active controlled-atmosphere technology to optimize the balance of oxygen and carbon dioxide within a refrigerated container, thus slowing respiration and the natural ripening of the commodity inside. This helps to preserve the quality of perishables beyond what refrigeration alone can do. Plus, as an active system, it generates high-purity nitrogen to more quickly displace oxygen, rather than relying on respiration alone to gradually reduce oxygen levels.
Key components are a sensor package, nitrogen membrane separator, air compressor and air filters. When in use, the compressor pulls fresh air into the system, which then removes water vapor from the compressed air stream before it enters the membrane separator. The hollow-fiber media of the separator extracts oxygen and captures carbon dioxide, discharging concentrated nitrogen into the container. If supplemental oxygen is needed, the membrane can be bypassed. The EverFRESH system can independently maintain oxygen at user-selected levels between 3-17% and carbon dioxide at between 2-19%.
Optional ethylene absorbers can be added for perishables where elevated levels of the hormone are a concern.
All EverFRESH systems have pre-trip inspection routines that test the membrane and compressor.