Abstract: A pressure tube includes a central tube section (10), an intake tube section (12) and a flared tube section (14). Flared tube section (14) includes a flange ring (54) with a shell (64) secured thereto. A contact ring (76) is received in an annular recess (82) of flange ring (54). Alternatively, a flared tube section (90) has an outer circumferential surface (96) that cooperates with a conical flange ring (110) that has an inner conical surface (114). The flange rings (54, 110) engage a flange (86) in the dome (85) of a pressure vessel.

Abstract: A pressure tube includes a central tube section (10), an intake tube section (12) and a flared tube section (14). Flared tube section (14) includes a flange ring (54) with a shell (64) secured thereto. A contact ring (76) is received in an annular recess (82) of flange ring (54).

Abstract: A process for desulfurizing molten steel comprising the steps of: removing converter slag from molten steel; adding a desulfurizing flux onto the molten steel from which the converter slag has been removed; supplying power to electrodes at a predetermined distance from the molten steel so as to generate an electric arc, the desulfurizing flux being melted by arc-heating so as to form the slag; and introducing a gas into the molten steel through a lance submerged into the molten steel to stir the molten steel and the slag which are arc-heated. In the process the desulfurizing flux is melted to a slag consisting essentially of 53 to 62% of CaO, 0 to 15% of SiO.sub.2, and 30 to 45% of Al.sub.2 O.sub.3.

Abstract: The object is to introduce a bottom-blown gas into a molten metal refining furnace so as to minimize the rate of blowing gas flow and increase the control range of the rate of blowing gas flow. There are included a refractory (1) having a plurality of holes (2) having an inner diameter of from 0.5 to 3.0 mm.phi. formed through said refractory and extending its working surface to its back, a metal cover (3) enclosing at least a part of the sides of the refractory (1) and a pressure box (4) formed in the bottom of the refractory (1) so as to communicate with the holes (2) and define a gas reservoir space. The molten metal is prevented from entering the holes (2) when the blowing gas pressure and the rate of blowing gas flow are decreased.