Suction heads for the removal of scum

摘要

A suction head for apparatus for removing slag or scum from the surface of molten metal or the like includes a suction pipe having a scum inlet at one end and communicating at the other end with a suction source by way of a conduit, a scum separator, etc. The suction head further includes a water cooling jacket provided around the suction pipe at least close to the scum inlet, and a water injector for injecting the water in the jacket into the suction pipe at a position close to the scum inlet. The water injection comprises a first nozzle for forcing out the water toward the axis of the suction pipe to cause the water to impinge against the sucked scum and to thereby rapidly solidify the scum on cooling, and a second nozzle for injecting the water into the suction pipe along the inner peripheral surface thereof to prevent the adhesion of the scum to the inner surface of the suction pipe. When desired, a water flow channel from the jacket to the first and second nozzles is provided with a shutter for closing the channel in an emergency to prevent the water from falling onto the molten metal.