Drum
Drum turns up in 2 fields: boilers, concrete. Here is what it means to the people in each one.
Drum in boilers
A large cylindrical vessel in a watertube boiler where steam separates from water or where sediment collects.
The steam drum at the top holds the working water level and contains separators and scrubbers that strip water droplets from the steam, along with feedwater, chemical feed and continuous blowdown piping. The lower mud drum collects sludge and feeds water to the tubes, and it is where bottom blowdown is taken. Drum level is the single most watched number in a watertube boiler room.
"Drum level is swinging plus and minus four inches on the load change, keep an eye on it or we'll trip on low water."
Drum in concrete
The rotating mixing barrel on a ready-mix truck, turning one way to mix and the other to discharge.
A tilted steel drum lined with spiral blades that keeps concrete mixed in transit and holds about 8 to 11 cubic yards on a standard US truck. Turning one direction folds the load inward; reversing walks the concrete up the blades and out the chute. After water or admixture is added on site, drivers turn it at mixing speed for at least 30 revolutions so the dose spreads through the whole load.
"Spin the drum on high for a couple minutes, I just put two gallons in and I don't want it all in the first wheelbarrow."