| 摘要 |
<p>Molten metal in an electric arc furnace is stirred by introducing a gas into the melt through tuyeres (5) mounted in the hearth (1). Each tuyere (5) has an inlet portion (6) having a passage (7) of relatively large diameter and an outlet portion (9) having a passage (8) of relatively small diameter. The tuyere (5) is mounted in the bottom of the electric arc furnace with the inlet portion (6) extending through the furnace shell (4) and part of the refractory brickwork (3). With this design of tuyere gas at conveniently available pressure (16 bar A) can be fed to the tuyere (5) and leaves the outlet portion (9) at least at sonic velocity thus forming a relatively stable jet which inhibits molten metal entering the tuyere (5). The outlet portion (9') may have a first portion (9'a) with a slightly larger internal diameter than a second portion (9'b) downstream of the first portion (9'a). When the second portion (9'b) is fully eroded the flow of gas increases and triggers an alarm. However, the internal diameter of the first portion (9'a) is still at least sonic to inhibit the ingress of molten metal into the tuyere (5'). <IMAGE></p> |
