https://www.kerone.in/drum-heating-ovens/
A drum heating oven is like a big heated box made to warm up barrels (drums) that are filled with stuff like oil, grease, wax, or syrup. Sometimes, things inside a drum are too thick or even solid, especially in cold weather. So we use this oven to warm them up and make them softer or more liquid so that they can be poured or pumped out easily.