Here is an auction for a Siegler stove that is very common around here. They hardly changed for decades. Most of these had a fuel tank attached to the rear that would hold 5-8 gallons of fuel, though most of the installations I see/saw didn't use tanks and had a tank outside high up on a rack. You can see the clean out tube in the next to last image.
http://www.ebay.com/itm/Antique-Deco...item2a163bc72b