Design and experiment of controlled atmosphere system based on liquid nitrogen injection for fresh-keeping transportation

A test platform of controlled atmosphere system based on liquid nitrogen injection was established, so as to control the oxygen and carbon dioxide level automatically in the container. A control scheme prior controlling the temperature was designed with double limited values. Bananas were used as experiment materials for controlled atmosphere system based on liquid nitrogen injection. The results indicated that the change of oxygen level was affected significantly by container tightness. Low container tightness would increase the operation frequency of the actuator and waste liquid nitrogen. The decreased rate of oxygen level was found not distinctly affected by different packages of bananas, whether plastic crate or carton, but mainly affected by different initial temperature. High initial temperature ensured constant liquid nitrogen injection and reduced consumed time, while low intial temperature caused intermittent nitrogen injection and required extra time. This temperature prior strategy was proved stable and could serve as reference for further development of fresh-keeping transportation equipment.