STEAM RING
It is not used for general flange but is used for heat exchanger connection or reactor connection.
Steam is used to prevent fire and gas leakage.
It is mainly used at high temperature and high pressure.
When the flammable liquid is used, the fluid leaks at a high pressure in the nozzle area When a fire occurs, steam is sprayed into the hole on the inside of the ring (nozzle side) to suppress the fire.