need to identify manway type on pressure vessel circa 1945

[joethib]

Have a manway type on an old pressure vessel that I do not know the type. It is 2 piece. the insert is the sealing part. The outside ring has the bolt circle and tightens to make the seal. The vessel was constructed in 1945. Just need to know what type manway this is.

 

[unclesyd]

Trying to find some information on you flange. In reality I/m looking for a 50 year old print of some 48" dia. autoclaves that had that particular type flange, later changed to a weldneck.
The claves were designed by DuPont and if I recall correctly some were built by Downingtown Iron Works.