气体置换装置是气调保鲜包装机的关键部件。设计了一种置换式新结构，分析了该全置换式气体置换装置的结构和工作原理，并进行了主要部件的设计计算与分析。为考察所设计全置换式装置的性能，与传统包装机进行配气比较试验研究。结果表明：所设计的置换式结构设计合理、紧凑，传统气调包装机气体置平均换率为97%，而所设计的置换式气调包装机气体置换率范围为99.7%，生产效率可达到每小时280~300包（双工位），相比于传统包装机，每100盒耗气量可减少0.33 kg，技术性能达得了预期目标。

Gas replacement device is the key component of MAP machine. A new gas replacement device was designed and its structure and working principle was analyzed. The main parts' parameters of the new type MAP machine were calculated and analyzed. The performances of the new device were compared with that of the traditional device. The results showed that the structure of the new device is reasonable and compact; the gas exchange rate is 99.7%, while of that of the traditional device is 97%; the production efficiency is 280~300 packets per hour(double location), and the gas consumption reduces 0.33 kg/100 boxes. The performance of the new device has reached the anticipated goal.