Water-tuyere
This class of tuyere is used at the blast-furnaces to protect the walls of the hearth from the intense heat that is generated by the hot blast in the neighborhood of the tuyeres. They are of various kinds; some being rectangular in section and made of either cast or wrought iron or bronze, while others are simply a spiral tube, used alone or cast within a solid block. This tuyere is kept cool by a circulating current of water.