Abstract: A rotary hearth furnace includes: a furnace body which surrounds a ring-like space; a hearth portion which forms a bottom portion of the ring-like space and is rotatable in the rotational direction; a gas exhaust portion which discharges an exhaust gas generated in the ring-like space to the outside of the furnace body; an introducing portion; and a flow rate regulating portion. The introducing portion is disposed upstream of the gas exhaust portion in the rotational direction and introduces a pressure regulating gas into a non-heating section of the ring-like space. The flow rate regulating portion is disposed between the introducing portion and the gas exhaust portion and regulates a flow rate of a gas by adjusting an opening area of the non-heating section.

Abstract: A rotary hearth furnace includes: a furnace body which surrounds a ring-like space; a hearth portion which forms a bottom portion of the ring-like space and is rotatable in the rotational direction; a gas exhaust portion which discharges an exhaust gas generated in the ring-like space to the outside of the furnace body; an introducing portion; and a flow rate regulating portion. The introducing portion is disposed upstream of the gas exhaust portion in the rotational direction and introduces a pressure regulating gas into a non-heating section of the ring-like space. The flow rate regulating portion is disposed between the introducing portion and the gas exhaust portion and regulates a flow rate of a gas by adjusting an opening area of the non-heating section.

Abstract: The present invention provides a method for producing a granular metallic iron in which an adhesion inhibitor leveler, an agglomerate leveler, a discharger, and the physical state of materials present on the hearth are optimized to thereby enable agglomerate to be spread in a single layer. The agglomerate hence is evenly heat-treated to enable high-quality granular metallic iron to be produced in satisfactory yield.

Abstract: The present invention provides a method for producing a granular metallic iron in which an adhesion inhibitor leveler, an agglomerate leveler, a discharger, and the physical state of materials present on the hearth are optimized to thereby enable agglomerate to be spread in a single layer. The agglomerate hence is evenly heat-treated to enable high-quality granular metallic iron to be produced in satisfactory yield.

Abstract: A rotary hearth furnace includes an exhaust gas eductor. The exhaust gas eductor includes a compartment-defining portion and an exhaust duct. The compartment-defining portion is provided on part of a ceiling of the rotary hearth furnace in an exhaust gas discharge region, and an exhaust duct is connected to the compartment-defining portion. The lower surface of the compartment-defining portion lies higher than the lower surface of the other portion of the ceiling. The compartment-defining portion defines a compartment where the exhaust gas stays. The exhaust duct can include a cooling medium injection nozzle. The furnace increases fuel efficiency by completely burning combustible components remaining in exhaust gas generated in the rotary hearth furnace so as to use the combustible components efficiently for the heating and reduction reaction in the rotary hearth furnace, without problems in producing reduced iron.

Abstract: A screw conveyor for conveying an object to be conveyed, supported by a casing 1 by rotation of a screw 2, in which wear of a screw blade and decrease in conveyance efficiency are prevented without the need for extra power. Load on an electric motor 3 or the like for rotating the screw 2 or a value corresponding to the load is measured, and if the value is equal to or larger than a preset upper limit value, a screw shaft 2a is lifted up to increase a gap between an edge of the screw blade 2b and a bottom portion of the casing 1.

Abstract: To provide a rotary hearth furnace which has a simple furnace structure in which the furnace is not damaged even if the furnace is operated for a long term while presenting general equations capable of adequately determining a thermal expansion margin in the rotary hearth furnace.

Abstract: A rotary hearth furnace includes an exhaust gas eductor. The exhaust gas eductor includes a compartment-defining portion and an exhaust duct. The compartment-defining portion is provided on part of a ceiling of the rotary hearth furnace in an exhaust gas discharge region, and an exhaust duct is connected to the compartment-defining portion. The lower surface of the compartment-defining portion lies higher than the lower surface of the other portion of the ceiling. The compartment-defining portion defines a compartment where the exhaust gas stays. The exhaust duct can include a cooling medium injection nozzle. The furnace increases fuel efficiency by completely burning combustible components remaining in exhaust gas generated in the rotary hearth furnace so as to use the combustible components efficiently for the heating and reduction reaction in the rotary hearth furnace, without problems in producing reduced iron.

Abstract: A screw conveyor for conveying an object to be conveyed, supported by a casing 1 by rotation of a screw 2, in which wear of a screw blade and decrease in conveyance efficiency are prevented without the need for extra power. Load on an electric motor 3 or the like for rotating the screw 2 or a value corresponding to the load is measured, and if the value is equal to or larger than a preset upper limit value, a screw shaft 2a is lifted up to increase a gap between an edge of the screw blade 2b and a bottom portion of the casing 1.

Abstract: PROBLEM TO BE SOLVED: To provide a rotary hearth furnace which has a simple furnace structure in which the furnace is not damaged even if the furnace is operated for a long term while presenting general equations capable of adequately determining a thermal expansion margin in the rotary hearth furnace.

Abstract: A sealing structure for a solid-transferring screw installed inside a heating furnace such as a material-leveling screw and a product-discharging screw, the sealing structure enabling the solid-transferring screw to be lifted during operation while airtightness of the heating furnace is retained. A driving shaft of the solid-transferring screw passes through through-holes formed in side walls of the heating furnace and is supported by liftable supporting devices disposed outside the furnace. Sealing blocks are attached on outer edges of the through-holes to surround the periphery of the through-holes at the outside of the furnace. Sliding panels are disposed at outer sides of the sealing blocks and have sliding holes for sliding the screw-driving shaft so that the driving shaft extends through the sliding holes. The sliding panels are brought into contact with the sealing blocks via the sealing members therebetween so that the sliding panels are slidable in the vertical direction.

Abstract: A sealing structure for a solid-transferring screw installed inside a heating furnace such as a material-leveling screw and a product-discharging screw, the sealing structure enabling the solid-transferring screw to be lifted during operation while airtightness of the heating furnace is retained. A driving shaft of the solid-transferring screw passes through through-holes formed in side walls of the heating furnace and is supported by liftable supporting devices disposed outside the furnace. Sealing blocks are attached on outer edges of the through-holes to surround the periphery of the through-holes at the outside of the furnace. Sliding panels are disposed at outer sides of the sealing blocks and have sliding holes for sliding the screw-driving shaft so that the driving shaft extends through the sliding holes. The sliding panels are brought into contact with the sealing blocks via the sealing members therebetween so that the sliding panels are slidable in the vertical direction.

Abstract: A rotary hearth furnace is provided to simplify detachment and assembly operations of a reduced iron discharging screw. At both side walls of an insulating housing 2a constituting in part of a furnace body 2 of a rotary hearth furnace 1 are installed through-holes which a spiral blade 42 of a reduced iron discharging screw 4 can pass through, each of the through-holes is closed by an inner hatch member 8 and an outer hatch member 9 which are externally mounted in a removable fashion to a rotary shaft 41 of the reduced iron discharging screw 4, an inner screw supporting device 10 is installed in the outside at an inner periphery side of the hearth 3 as well as an outer screw supporting device 20 is installed in the outside at an outer periphery side of the hearth 3. The reduced iron discharging screw 4 is detached from the furnace body 2 via the through-holes and assembled to the furnace body 2 via the through-holes by using the inner screw supporting device 10 and the outer screw supporting device 20.

Abstract: An annular rail 6 is fixed on the lower surface of a moving hearth 2, and the rail 6 is supported from below by support rollers 7 provided with elevating devices 8. The moving hearth 2 is continuously or intermittently moved downward by the elevating devices 8 depending on the thickness of a metal oxide layer formed by the deposition of powder of metal oxide agglomerates mixed into the furnace together with the metal oxide agglomerates so that a gap is provided between the surface of the metal oxide layer and the edge of the blade of a discharge screw 4 during operation.

Abstract: Heat-treated products discharged from a discharge port of a movable hearth type heat treatment furnace, for example a rotary hearth type reduction furnace are discharged to a sorting means, the heat-treated products that foreign substances have been removed, are discharged through a seal leg into which anti-reoxidation gas is blown from a gas blowing nozzle, to a receiving recess of a receiving pan provided within a case having a hopper attached thereto which is a feeding means, and then a scraper is swung to discharge the heat-treated products deposited on the top surface of the receiving recess from the longitudinal ends of the receiving pan and simultaneously to quantitatively feed it to a molten iron-manufacturing furnace 8, which is a downstream side facility, from the bottom side discharge port of the casing having a hopper attached thereto, and in addition, dust removal/cooling means for produced gas of the molten iron-manufacturing furnace and means for regulating the amount of produced gas are provid

Abstract: A rotary hearth furnace is provided to simplify detachment and assembly operations of a reduced iron discharging screw. At both side walls of an insulating housing 2]a constituting in part of a furnace body 2 of a rotary hearth furnace 1 are installed through-holes which a spiral blade 42 of a reduced iron discharging screw 4 can pass through, each of the through-holes is closed by an inner hatch member 8 and an outer hatch member 9 which are externally mounted in a removable fashion to a rotary shaft 41 of the reduced iron discharging screw 4, an inner screw supporting device 10 is installed in the outside at an inner periphery side of the hearth 3 as well as an outer screw supporting device 20 is installed in the outside at an outer periphery side of the hearth 3. The reduced iron discharging screw 4 is detached from the furnace body 2 via the through-holes and assembled to the furnace body 2 via the through-holes by using the inner screw supporting device 10 and the outer screw supporting device 20.

Abstract: A rotary hearth furnace is provided to simplify detachment and assembly operations of a reduced iron discharging screw.

Abstract: A rotary hearth furnace is provided to simplify detachment and assembly operations of a reduced iron discharging screw.

Abstract: An annular rail 6 is fixed on the lower surface of a moving hearth 2, and the rail 6 is supported from below by support rollers 7 provided with elevating devices 8. The moving hearth 2 is continuously or intermittently moved downward by the elevating devices 8 depending on the thickness of a metal oxide layer formed by the deposition of powder of metal oxide agglomerates mixed into the furnace together with the metal oxide agglomerates so that a gap is provided between the surface of the metal oxide layer and the edge of the blade of a discharge screw 4 during operation.

Abstract: Heat-treated products discharged from a discharge port of a movable hearth type heat treatment furnace, for example a rotary hearth type reduction furnace are discharged to a sorting means, the heat-treated products that foreign substances have been removed, are discharged through a seal leg into which anti-reoxidation gas is blown from a gas blowing nozzle, to a receiving recess of a receiving pan provided within a case having a hopper attached thereto which is a feeding means, and then a scraper is swung to discharge the heat-treated products deposited on the top surface of the receiving recess from the longitudinal ends of the receiving pan and simultaneously to quantitatively feed it to a molten iron-manufacturing furnace 8, which is a downstream side facility, from the bottom side discharge port of the casing having a hopper attached thereto, and in addition, dust removal/cooling means for produced gas of the molten iron-manufacturing furnace and means for regulating the amount of produced gas are provid