Abstract: A piston rod and cylinder seal device includes a cylinder defining a piston chamber extending between first and second cylinder heads. The second cylinder head has a spud receiving bore, a pressure passage communicating with the spud receiving bore, and a bore supply/vent passage. A first piston is disposed in the piston chamber. A piston rod is connected to the piston, the piston rod having a piston rod spud extending beyond the first piston and including a blind shaft receiving bore. A second piston slidably disposed in the blind shaft receiving bore has a seal member connected thereto. A contact member connected to the second cylinder head in the spud receiving bore has a central passage extending therethrough in communication with the bore supply/vent passage. The seal member when contacting the contact member acts to seal the central passage.

Abstract: Apparatus for operating a shaft furnace, whereby an upper section of the shaft furnace is charged with raw materials which due to gravity descend inside the furnace while the atmosphere prevailing within the shaft furnace causes part of the raw materials to melt and/or to be reduced, and in a lower section of the shaft furnace a process gas is injected so as to at least partly modify the atmosphere prevailing in the shaft furnace. The pressure and/or volume flow of the injected process gas is dynamically modulated within a time span of 40 s. Also, a shaft furnace operable by said method, thus achieving improved through-gassing.

Abstract: Method for operating a shaft furnace, whereby an upper section of the shaft furnace is charged with raw materials which due to gravity descend inside the furnace while the atmosphere prevailing within the shaft furnace causes part of the raw materials to melt and/or to be reduced, and in a lower section of the shaft furnace a process gas is injected so as to at least partly modify the atmosphere prevailing in the shaft furnace. The pressure and/or volume flow of the injected process gas is dynamically modulated within a time span of 40 s. Also, a shaft furnace operable by said method, thus achieving improved through-gassing.

Abstract: Method for operating a shaft furnace, whereby an upper section of the shaft furnace is charged with raw materials which due to gravity descend inside the furnace while the atmosphere prevailing within the shaft furnace causes part of the raw materials to melt and/or to be reduced, and in a lower section of the shaft furnace a process gas is injected so as to at least partly modify the atmosphere prevailing in the shaft furnace. The pressure and/or volume flow of the injected process gas is dynamically modulated within a time span of 40 s. Also, a shaft furnace operable by said method, thus achieving improved through-gassing.

Abstract: All of the air is compressed in a single compressor, which feeds a smelter for smelting ore, a converter for converting matte coming from the smelter and an air separation unit which delivers two oxygen streams for enriching the air. A buffer tank is used to deliver a variable flow of enriched air to the converter.

Abstract: An apparatus for regulating the feed or delivery of hot air in the tuyere stock of a shaft furnace, and a tuyere stock which incorporates such a regulating apparatus is presented. The regulating apparatus may be used in conjunction with a tuyere stock for a shaft furnace (the structure of which is well known) and consists of an articulated pipe connecting a large circular conduit to a nozzle and which is fitted internally with a refractory lining having an internal channel therethrough for the passage of air. The regulating apparatus of the present invention comprises a valve substantially in the form of a disc which is adapted to operate in a spherical portion of the internal channel described above. The disc is removably mounted on the end of a rod, the rod being rotatably and hermetically mounted in a tubular support integral with the wall of the tuyere stock and connected on the outside thereof to a mechanism which serves to pivot both the rod and the valve about the longitudinal axis 0 of the rod.

Abstract: A pulverized material, particularly coal or lignite, is maintained in a fluidized state in a storage container and is released therefrom into a carrier gas stream. The gas for causing fluidization and maintaining a pressure in the container which is greater than the carrier gas pressure is in part obtained by recycling gas vented from the container, the vented gas being filtered and increased in pressure. The vented gas may also be employed to aid in the delivery of the pulverized material into the container.

Abstract: A process for the direct reduction of iron ore in a shaft furnace having an upper reducing zone and a lower cooling zone in which reducing gas is introduced to the furnace at the bottom of the reducing zone around the periphery of the furnace, exhausted reducing gas or top gas is removed from the top of the furnace, cleaned, mixed with additional hydrocarbons, and reinjected into the furnace below the reducing zone. The hot reducing gas is injected serially into different sectors of the cross-section of the furnace and at varying velocities to force upflowing cleaned top gas to change its flow path or its flow rate, or both, periodically. Apparatus for accomplishing the method is also disclosed.

Abstract: A reduction process and apparatus wherein the flow of the reducing fluid through the fixed bed of iron ore, oxidized pellet or the like to be reduced is reversed in direction so that the iron ore, oxidized pellet or the like, at any place in the bed, may be reduced uniformly.

Abstract: A pulverized solid fuel is injected into a shaft furnace by being entrained in a stream of pressurized air, the resulting fuel-air mixture subsequently being further mixed with heated air being delivered to the furnace via a tuyere. The air used to entrain the pulverized fuel is diverted from the cold air supply to a mixing station, which is used to control the temperature of the hot air supplied to the furnace via the tuyere, and this diverted air is pressurized prior to the pulverized material entrainment.

Abstract: Method and apparatus are described for the controlled cooling of processed oxidic ores in a shaft furnace in order to produce an improved product. Means are provided in the cooling section of the furnace chamber that enable the chamber to be divided into separate regions within each of which the admission of low temperature reducing gas can be regulated in order to more effectively control the distribution of reducing gas across the furnace.

Abstract: A method of producing metallic iron pellets in a generally vertical furnace in which a gravitational flow of particulate material is reduced in a reducing zone by a countercurrent flow of a reducing gas containing a reductant, the spent reducing gas is removed and cooled and a portion is introduced as a cooling gas in a cooling zone near the bottom of the furnace while a second portion is employed as a fuel to heat a catalyst through which a gaseous hydrocarbon and steam are passed to form a reducing gas mixture for introduction into the furnace, and a portion of the cooling gas is upgraded in reducing potential and introduced to the reducing zone as reducing gas. Apparatus is also provided for carrying out the method.

Abstract: A method and an apparatus for stopping the flow of metal from the taphole of a furnace. The method comprises the step of blowing air into the taphole with sufficient pressure to reverse the flow of the molten metal, and then reducing the pressure to a value sufficient to hold the metal in the furnace. The apparatus comprises a pipe adapted to be inserted into the taphole and of sufficient dimension to seal the taphole, and means for blowing air into the pipe initially at a predetermined pressure so as to reverse the flow of the molten metal in the taphole and then at a reduced pressure sufficient to hold the metal in the furnace.