Picture a single moving conveyor stopping at fix points (stations) the unit then moves down to whatever is on the conveyor and then moves back to get out of the way. It's possible that it could have been designed to actually work with a moving conveyor as well to keep the flame (I think that's a given at this point) on the target while the conveyor moved.
Feel like taking that ceramic mount off and snooping around inside to see how it's constructed? What about the brass port, I don't see bolts on that but it looks like it may be threaded?
My best guess is that the circular lower lower portion with the holes was fed natural gas, I'm guessing those holes are aimed at an angle not straight up, it looks like something that had a focal, point. IF the target were small the upper portion looks like it would be a vacuum intake to suck in exhaust gas AND AMBIENT AIR. By the time the ambient and exhaust gas mixed in that ceramic module the temperature was low enough to keep the bulk of the unit from heating up.
Think of it as a pulse heater for a very small target, like maybe 1/4 inch max.