You may look for ASME Mfrs using Sec X, pressure vessels made of fiberglass and other non-metalic ASME.org
There are several in the State of Texas, US
ER
I personally wouldn't want to have propane at this pressure in something like this (visions of glass run through my head when I see 'transparent' though I know there are other materials out there as an option).
I need to visualize the process inside the pressure vessel so thats the reason I'm looking for Transparent Pressure vessel.
I also had Plexiglas in my mind but I’m afraid if I tight the bolts to fix the flanges, the Plexiglas will crack.
I checked with vendors for thick clear PVC but they said I can't use PVC for gas. PVC is only for liquid chemicals.
Could you pls suugest me what other materials are there as an option?
and ask for Lance F (I won't give his whole name here) in the test lab. Graham has a lab where they do vacuum training, and in order to see the process, they have glass heat exchangers, etc. They might be able to give you some guidance as to where the "getting place" is for that kind of equipment