Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/15—Tapping equipment; Equipment for removing or retaining slag
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
  • F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
  • F27B3/19—Arrangements of devices for discharging
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/18—Door frames; Doors, lids, removable covers
  • F27D1/1858—Doors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/14—Charging or discharging liquid or molten material

Definitions

• the object of the present invention is a cooled plug capable of rendering the scrubber door of a sealed arc furnace; it brings, among other benefits, energy savings and improvements in oven productivity.
• the scrubber door of an arc furnace supplied with alternating current as with direct current is an orifice of more than one square meter located in the side wall of the furnace, also called tank top, closed by a sliding door operated pneumatically, hydraulically or electrically.
• the main disadvantage of this scrubber door is that it is very difficult to have a correct seal and that it is too frequently kept open, in whole or in part, during the normal cycle of production.
• the air inlets, amplified by the smoke collection system, produce thermal losses of up to 8% of the electrical energy consumption.
• a secondary disadvantage of the scrubber door is that its design imposes a large door threshold inside the furnace, on which accumulates from 500 kg to 1 ton of scrap during the loading of the baskets and that these scrap, distant from the center of the oven, become all those loaded in the most difficult oven to melt.
• the scrubber door is also installed in a rather cold area of the furnace and the melting of the scrap that is on the threshold of the slag door is further delayed.
• - serves as a inspection door to inspect, from the outside, the state of refractory wear and interior walls of the furnace between two casting cycles.
• the main function of the sludge door is the removal of the slag from the furnace crucible to the slag tank or the soil and the quantities to be discharged as the instantaneous flow rates do not require an opening of this size.
• the slag can be discharged from the furnace by an orifice of a section close to a square decimetre and, in the case of foaming of this slag, the interior volume of the furnace easily contains the foaming slag as long as its specific gravity remains greater than 0.12 tonnes per cubic meter; for castings of 120 tons of liquid metal there are 12 tons of slag with an available volume of 100 cubic meters in the "upper part of the tank" or a specific mass of 0.12 tons per cubic meter to fill the entire space available; having a slag of lower specific gravity is very exceptional and in this case the reduction of the electrical power instantly limits the foaming of the slag.
• the invention by effectively closing the hole of the door in the tank top, allows: - to reduce the surface of the opening in the oven tank; the door plug closes an orifice, either square or semicircular, of a fifth to a half square meter arranged in the top of the furnace tank in place of the conventional door;
• the cap is applied by its upper face and its side faces to the top of the furnace tank whose reinforcements are arranged to match the shape of the cap; the bearing faces are lined with cast iron plate or graphite to ensure proper positioning of the door plug and thus a good seal in the closed position; the lower face of the cap is supported on the refractory lining of the door sill, the upholstery maintained by the operators in height and flatness;
• the door plug preferably remains supported by its upper face on the corresponding wall of the top of the furnace tank, creating a rectangular and horizontal passage between the underside of the door plug and the slagging threshold for the slag discharge, while limiting the air intakes; to ensure that the closure of the passage through the stopper reaches the lower surface of the water-cooled panels of the top of the furnace tank; the threshold of the door is then reduced to a minimum and there is no more accumulation of scrap difficult to melt.
• the invention relates to the establishment of a prismatic or frustoconical plug, male in a housing of female form which is identical and arranged in the top of the electric furnace tank.
• This cap metallic, is cooled with water; this cooling is of similar design to that of water-cooled panels that fill the inside of the top of the furnace tank.
• the inner face of the oven is optionally reinforced by pins welded therein to have a better grip of the slag, better resistance to shocks scrap and a low sensitivity to electrical priming.
• a ceramic coating is envisaged as an alternative to the basic design.
• This cap keeps a certain mobility on its support to be able to be put in place in its housing which is subject to deformations over time and whose position relative to the working floor depends on the inclination of the oven; indeed the oven is usually in a horizontal position but it can be tilted a few degrees, forwards or backwards, during part of the casting cycle, during which time the cap must ensure the sealing of the cleaning door.
• the mobility of the plug is obtained thanks to an articulated connection with horizontal axis with:
• the handling mechanism has adjustment means and position control which are links or boxes springs or hydraulic cylinders or any other equivalent mechanical means.
• the door plug is removed by the handling mechanism that supports the plug and away from its normal working position.
• the movement is either straight with a carriage that moves in the axis of the door, either rotating with a bracket placed on the fixed floor or the mobile floor of the oven.
• the carriage easily assures precise positioning of the plug which then moves in a vertical plane.
• a stem when the axis of rotation is vertical the plug moves in a horizontal plane when the axis of rotation is vertical; when the axis of rotation is inclined the movement takes place in an inclined plane or even curved to allow the immediate release of the threshold of the door by pivoting upwards.
• the implementation of the cap and its removal are done by following the inclined upper part of its housing in the top of the tank to leave a space under the door plug, space through which the slag of the oven is removed, without have a full opening of the door.
• the door cap In the closed position the door cap is equipped with two auxiliary means, - one for its holding in position on the top of the tank, a clamage for example, which releases the mechanism of maintaining the door cap of a permanent effort the other to exert a tearing force at its opening, such as a hydraulic cylinder for example, the slag that lines the inside of the oven exerting a possible retention of the door plug in the closed position.
• two auxiliary means - one for its holding in position on the top of the tank, a clamage for example, which releases the mechanism of maintaining the door cap of a permanent effort the other to exert a tearing force at its opening, such as a hydraulic cylinder for example, the slag that lines the inside of the oven exerting a possible retention of the door plug in the closed position.
• the door cap may comprise a passage opening of an injection lance or of a temperature measurement or sample taking lance, to the detriment of a less good seal.
• the underside of the door plug consists of a piece of refractory material insensitive to contact with the metal in the event of inadvertent overflow thereof.
• Such a door plug brings electrical and fossil energy savings, a better homogeneity of the melting of scrap in the furnace, a reduction of the capacity of collection of fumes and consequently an improvement of the productivity of the furnace.
• Figure 1 shows a top view and in sectional elevation, the door cap object of this patent.
• 2 shows, in plan view, a section of the part of the oven corresponding to the sludge door with the door plug in the "closed” position and a handle for handling the door plug.
• Figure 3 shows elevational view of the same part of the tank with the door plug in the "closed” position.
• the prismatic door plug 1 as shown in FIGS. 1, 2 and 3, is a metal assembly cooled by water by a steel tube 10 embedded in plates 11 to ensure good contact with the housing arranged in the upper part. 6.
• the door plug 1 is supported and held in place by means of the uncooled support 2, driven by the support 3, two movements in the axis of the door, one vertical and the other horizontal thanks to the suspension rods 31 and 32 and a lateral movement evacuation of the assembly to a parking position by rotation of the arm 4.
• the door cap 1 has a prismatic shape which fits the structure 6 of the top furnace tank, filled with cooled panels 61 and the door sill 5 made of refractories 62 which fill the structure 63 of the bottom of tank.
• the underside of the door plug 1 may be in contact with the scrap charged to be melted.
• the contact surfaces between the door plug 1 and the top of the tank 6 are contiguous in the planes 12, 13 and 14. These contact planes 12, 13 and 14 have a low coefficient of friction in order to facilitate the installation of the plug 1 in the top of tank 6.
• the movements of the supports 2 and 3, controlled by the rods 31 and 32 are such that the upper surface of the door plug 1 comes first to rely on the surface 12 and then sliding on this surface is applied on the walls 13 and 14 and on the door sill 5.
• the clamps 23 secured to the support 2 of the assembly of the door plug 1 hook the reinforcements 65 of the tank 6 to ensure the closed position of the door plug 1 during the production cycles of the electric oven.
• the control of these damages, opening and closing, is made by 2 hydraulic cylinders 25 installed in the support 2 of the door plug 1.
• the mechanism 26 makes it possible to pull back the door plug 1 after opening the clamage by means of the 2 hydraulic jacks 24.
• the door plug 1 is then retracted by the support 3 and the jib 4: the scrubber door is then opened.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Vertical, Hearth, Or Arc Furnaces (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=34958550

Family Applications (1)

Country Status (2)

Families Citing this family (5)

Family Cites Families (9)

• 2004
  • 2004-08-09 WO PCT/IB2004/002577 patent/WO2006016201A1/fr active Application Filing
  • 2004-08-09 EP EP04769116A patent/EP1784611A1/de not_active Withdrawn

Non-Patent Citations (1)

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