Difference between internal and external flanges
It's a pairing! There should be drawings! It should be non-standard
The inner flange is the flange that connects the inner part and the pipe of the equipment, and generally does not bear the pressure load.Flanges (Flange), also called flanges, flanges, or flanges. A flange is a part that is connected between the pipe and the pipe, used for the connection between the ends of the pipe. It is also used for the flange on the entrance and exit of the equipment. It is used for the connection between the two devices, such as the reducer flange.
Flanges that connect internal parts and pipes within the equipment generally do not withstand pressure loads
