Abstract: A nozzle or nozzles for spraying cooling water are disposed at the lower end of a slag suction path. A cooling water down-flow passage is provided on the outer periphery of an inner tube which constitutes a slag suction path. A water sump is provided below the cooling water down-flow passage, the water sump being located lower than the each nozzle. A lower end opening of the cooling water down-flow passage is disposed lower than the each nozzle and is submerged in water in the water sump. The cooling water down-flow passage, except the lower end opening, is adapted to be closed up. When the cooling water down-flow passage is closed up, water in the passage is stopped by atmospheric pressure acting upon the surface of the water in the water sump, so that it is prevented from flowing down.

Abstract: In a scum removing apparatus including a suction source, a suction pipe having one end communicating with the suction source and the other free end positioned above the surface of scum to suck the scum and apply water to the sucked scum in the vicinity of the free end, and a scum separator provided at an intermediate portion of the suction pipe, a device for detecting the level of the scum surface relative to the free end of the suction pipe. The detecting device comprises a pair of electrode rods provided on the outer periphery of the free end of the suction pipe and projecting from the pipe end by a suitable length, and means for detecting variations in the electric resistance between the electrode rods. The electrode rod comprises a tube having accommodated therein a slider slidingly projectable from the front end of the tube and slidingly retractable into the tube.

Abstract: A method of removing slag or like scum from the surface of molten metal by suction. A tubular gaseous stream directed toward the surface of scum is formed, with its interior space communicating with a suction source such as an ejector or vacuum pump. The gaseous stream hampers the inflow of external air into the suction zone surrounded by the stream. On reaching the scum surface, the gaseous stream flows inward along the scum surface and is thereafter drawn toward the suction source, so that the stream acts to blow the scum radially inwardly of the stream and thereafter raises the scum from the surface of molten metal, thus permitting efficient removal of the scum with a relatively low suction. A scum removing apparatus for practicing this method includes a suction source, a suction head communicating with the suction source, and annular nozzle means provided around the suction head for forming a tubular gaseous stream flowing toward the surface of scum.

Abstract: A telescopic assembly for pipes for conveying powdery to granular materials entrained in an air or like gaseous stream comprises two pipes of different diameters coaxially fitting one within the other and axially slidable relative to each other, a labyrinth packing provided around a front end portion of the inner pipe for preventing leakage of the stream or ingress of the atmosphere through the clearance between the two pipes, and a scraper attached by a plate spring to the retainer ring of the labyrinth packing on the front end of the inner pipe and in pressing contact with the inside peripheral surface of the outer pipe. Rollers carried by the outer pipe engage the outer surface of the inner pipe and aid in maintaining a uniform clearance between the two pipes.

Abstract: Structure for supporting the excavated wall of a tunnel comprises a plurality of unit pipe support members connected in end-to-end relation by pipe couplings with lap joints, or by flanges on the ends of the support members, to form a plurality of sub-assemblies which are then connected by a closure member to form a pipe support having a periphery substantially conforming to the periphery of the tunnel wall, and having ports through which the pipe support can be filled with mortar or concrete. The unit pipe support members are substantially the same size and shape for mass production from ductile cast iron or cast steel and are provided with integral reinforcing ribs.

Abstract: 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.

Abstract: Slag on the surface of a molten metal is drawn into the inlet end of a suction pipe which is provided with a water cooling jacket having orifices permitting the flow of water to the inlet end of the pipe for pelletizing the entering slag. The suction pipe is connected to a separator hopper, which is evacuated by an exhaust pump to create the suction, and which includes a slag discharge port closed by an openable valve. A sealed auxiliary hopper receives slag from the discharge port of the separator hopper when the valve thereof is opened, and also includes a slag discharge port closed by an openable valve. The hopper discharge valves are operated alternately by suitable control means so that when one valve is open the other is closed, thereby enabling slag to be continuously sucked, separated, and intermittently discharged from the auxiliary hopper.