The management of the blind plate in and out of the device belongs to the production workshop, that is, after entering the device valve and before exiting the device valve, the blind plate can only be added after stopping work and returning materials. In actual production, due to the hot work outside the inlet and outlet valves, the unit in charge of system piping added a blind plate in front of your inlet valve and behind your outlet valve.
This is the management authority of different units. It is easy to explain your own situation clearly, but it is not easy and unnecessary to explain others' situation clearly.
Blind plates are added in front of the root valve, such as steam for line sweeping, nitrogen for replacement or pressurization, fresh water for start-up and shutdown, etc., so as to facilitate removal and addition at any time.