When joining union-end valves, or when flanging end connectors, never make the joint to the end connectors while they are attached to the valve body.

• 为了防止与管接螺母相关的事故，在连接到端口连接件之前，先将其(最小的内径朝前)滑入管道或管嘴和法兰毂(当法兰连接时)上。