1. In the initial start-up phase, when the strength or tightness test of the pipeline can not be carried out at the same time as the connected equipment (such as turbine, compressor, gasifier, reactor, etc.) , a blind shall be provided at the connection of the equipment to the pipe.
2. When the device is stopped, if the pipeline is still in operation, a blind plate is arranged at the cut-off Valve.
3. When the device is multi-series, the main pipe from outside the boundary area is divided into thousands of pipes entering each series, and the block valve of each branch pipe is equipped with block plates.
