Heaters are "suspended" while in use in the reefer and I use that word in lack of a better one.
They are chained in three or four places radially around the heaters anchored equal distance from the bunker walls. Not touching the floor either.
I have to think this is a two man job as someone has to clip the heater to the bunker walls once it is lowered and another man to pull the first person out as a safety measure.
I used to have a heater I had picked up cheap ($25) at a railroad flea market. I left it behind somewhere knowingly as I came later question what value it really held.
I would agree that 18 - 24 inches of diameter with 30 inches in height is close enough to get an idea of size.
I will look up some images I have and post them. Jim Dick - St. Paul