可燃制冷剂空调用开关元件点燃危险及防爆试验分析

随着全球范围对环境问题的日益重视，R290，R32等新型制冷剂因优良的环保性能和节能效果被广泛应用于空调行业，但其属于IIA级爆炸性气体，为了进一步分析其运行过程中的防爆安全性能。通过文献数据和测试分析，可燃制冷剂空调电气元件的点燃源主要来自其工作过程中产生的电气火花。其中空调开关元件最容易产生电火花、电弧，且通过试验验证这些火花或电弧能点爆（6.5±0.5）%乙烯/空气混合物。综合IEC 60335-2-40，GB 4706.32标准要求和空调开关元件的结构特征，分析确定其应符合“nC”型防爆技术要求，并能通过“nC”型爆炸试验。针对开关元件结构尺寸小、存在爆炸试验中爆炸性混合气体多次置换和负载通、断电操作的难点问题，提出一套合理可行的爆炸试验实施方案，并通过测试应用得到验证。

Analysis on ignition risk and explosion proof test of switching elements for air conditioner with flammable refrigerant

With the increasing attention to the environmental issues on global scale,the new refrigerants such as R290 and R32 are widely used in the air conditioning industry due to their excellent environmental performance and energy saving effect,but they are IIA grade explosive gases.In order to further analyse the explosion-proof safety performance during the flammable refrigerant air conditioner operation,according to the literature data and test analysis,it showed that the ignition source of electrical elements in the air conditioner with the flammable refrigerant was mainly the electric sparks generated in the process of operation.The switching elements of air conditioner were most likely to generate the sparks and arcs,and through the tests,it was verified that these sparks or arcs could ignite the (6.5±0.5) % ethylene/air mixture.According to the requirements of IEC 60335-2-40 and GB 4706.32 and the structural characteristics of switching elements in the air conditioner,it was determined that they should meet the technical requirements of “nC” type explosion proof and pass the explosion type test of “nC” type.Aiming at the difficult problems of the small structure size of switching elements,multiple displacement of explosive gas mixture,and load power on and power off operation in the explosion test,a reasonable and feasible implementation scheme of explosion test was put forward and verified by the testing application.