Tuyeres

Air or oxygen is injected into a hearth under pressure from bellows or a blowing engine or other devices. This causes the fire to become hotter in front of the blast than it would otherwise have been, enabling metals to be smelted or melted or made hot enough to be worked in a forge, though these are blown only with air. This applies to any process where a blast is delivered under pressure to make a fire hotter. Archeologists have discovered tuyeres dating from the Iron Age; one example dates from between 770 BCE and 515 BCE.