In order to prevent mishaps with the union nut, slide it (smallest bore first) over the pipe or nipple-and-flange hub (when flanging) before making the joint to the end connector.

• 为了防止管接头螺母的意外事故，在连接到端口连接件之前，(先从最小的阀腔开始)将它滑到管道或管嘴-法兰中枢上(当进行法兰连接时)。