Charging shaft system with increased reliability

Abstract

Charging shaft system (20) with a shaft-shaped container (31) which has an actuatable closure device (71) closing a feed opening (27), a discharge opening (21) and at least one suction opening (91) assigned to a preheating area (102) of the shaft-shaped container (31), wherein a shaft slide device (61) with at least one movable shaft slide (62; 67) within the shaft-shaped container (31) delimits a precharging compartment (101) from the preheating area (102), characterized in that - that at least one further suction opening (81) is assigned to the pre-charging compartment (101), - that the pre-charging compartment (101) is delimited by an impact wall (41) which has an inclination of between 30 degrees and 45 degrees, including the two end values, to a horizontal plane, wherein each vector oriented in the direction of inclination of the impact wall (41) lies in a straight line which penetrates the travel path of at least one shaft slide (62; 67) within the shaft-shaped container (31), - that a vertical projection of the feed opening (27) onto the impact wall (41) lies at least 75% on the impact wall (41).

Description

[0001] The invention relates to a charging shaft system with a shaft-shaped container which has an actuatable closure device closing a feed opening, a discharge opening and at least one suction opening associated with a preheating area of ​​the shaft-shaped container, wherein a shaft slide device with at least one movable shaft slide within the shaft-shaped container delimits a precharging compartment from the preheating area.

[0002] From DE 10 2010 045 825 A1 a charging shaft system is known in which the feed material is conveyed from the precharging compartment to the preheating area by means of a pusher basket.

[0003] DE 10 2017 124 108 A1 proposes to store the feed material to be preheated in a channel arranged at an angle of 5 degrees to 15 degrees to the horizontal, from which the preheated feed material is to slide or be conveyed into the furnace vessel.

[0004] The present invention is based on the problem of developing a low-emission charging shaft system with a low failure rate and thus with increased reliability.

[0005] This problem is solved by the features of the main claim. For this purpose, at least one additional extraction opening is assigned to the pre-charging compartment. The pre-charging compartment is defined by an impact wall that has an inclination of between 30 degrees and 45 degrees, including the two end values, relative to a horizontal plane. Each vector oriented in the direction of inclination of the impact wall lies in a straight line that traverses the travel path of at least one shaft slide within the shaft-shaped container. A vertical projection of the feed opening onto the impact wall lies at least 75% on the impact wall.

[0006] The charging shaft system is loaded with the feed material through the loading opening into the pre-charging compartment with the closing gate open. The gate valve, which separates the pre-charging compartment from the preheating area, is initially closed. The feed material, e.g., 100 tons of steel scrap, falls largely onto the impact wall. This impact wall is positioned at an angle in the room, so that the scrap builds up on the impact wall and the shaft gate valve. During loading, the dynamic momentum of the falling scrap primarily impacts the impact wall. The shaft gate valve is essentially statically loaded by the mass of the scrap. This reduces the risk of damage to the shaft gate valve.

[0007] The charging shaft system has at least one extraction opening in the preheating area and at least one extraction opening in the precharging compartment. The exhaust gases used to preheat the feedstock, for example, from an electric arc furnace, are extracted via the extraction opening in the preheating area. These exhaust gases from the electric arc furnace are generated during the melting process of the feedstock and are drawn in through the discharge opening.

[0008] The extraction opening in the pre-charging compartment primarily extracts cold dust released during the unloading of the scrap basket. If the shaft gate valve and / or the pre-heating area extraction system fails, the pre-charging compartment extraction system can be used in addition to the exhaust gases from the melting process and pre-heating.

[0009] Further details of the invention emerge from the subclaims and the following description of schematically illustrated embodiments. Fig. 1: Charging shaft system with furnace vessel; Fig. 2: Section of the charging shaft system; Fig. 3: impact floor; Fig. 4: Detail of the fastening of the wear plates; Fig. 5: Variant of a charging shaft system with two shaft valves; Fig. 6: Scrap pushing device.

[0010] The Fig. Figure 1 shows a charging shaft system (20) and a furnace vessel (11) as parts of an electric arc furnace system (10). To operate the electric arc furnace system (10), feedstock, e.g., steel scrap, is conveyed intermittently or continuously from a scrap yard into the charging shaft system (20) by means of a conveyor. The density of the feedstock is less than one-tenth of the density of liquid steel, e.g., 7850 kilograms per cubic meter. For example, a tapping mass of 100 tons of liquid steel requires the use of more than 200 cubic meters of scrap.

[0011] The charging shaft system (20) has a discharge opening (21) through which the feed material is conveyed from the charging shaft system (20) into the furnace vessel (11), cf. Fig. 2. In the furnace vessel (11), the feed material is heated, e.g., using electrical and / or fossil energy, to a temperature above the melting point, e.g., to 1680 degrees Celsius. Once the molten bath is homogeneous, the liquid end product, e.g., liquid steel, is poured through a tap hole in the furnace vessel (11), e.g., into a ladle located beneath the furnace vessel.

[0012] During the melting process, the furnace vessel (11) is tilted in the opposite direction to the tapping direction for slag removal. The furnace vessel (11) rolls, for example, along roller tracks. After the melting process is complete, the furnace vessel (11) is rolled in the tapping direction along the roller tracks for tapping and emptying, tilting up to 16 degrees from a horizontal position.

[0013] During the melting process, the charging shaft system (20) is connected to a filling opening of the furnace vessel (11), for example, by means of a sliding sleeve (not shown here). It is conceivable to design the transition between the charging shaft system (20) and the furnace vessel (11) without a sliding sleeve.

[0014] For maintenance purposes, the charging shaft system (20) has a drive system (not shown here) that allows it to be moved, for example, along rails located on the hall floor. These rails are oriented perpendicularly to the tapping direction of the furnace vessel (11). The charging shaft system (20) can be moved along these rails by a distance of, for example, two meters, in order to remove the furnace vessel (11) or insert a new one.

[0015] The charging shaft system (20), see the Fig. 1 and Fig. 2, has a support frame (22) which, together with a support structure (23), supports a shaft-shaped container (31). The shaft-shaped container (31) has an addition opening (27) of the charging shaft system (20) at its upper rear end. The discharge opening (21) oriented towards the furnace vessel (11) is arranged at its front lower end. For example, all wall sections (33 - 36) of the shaft-shaped container (31) can be water-cooled. In the exemplary embodiment, the water is distributed via the support structure (23). For example, the cooling circuits of the individual wall sections (33 - 36) can be hydraulically connected in parallel. It is also conceivable to provide two or more cooling circuits for one wall section (33; 34; 35; 36). The entire water cooling of the shaft-shaped container (31) can be designed as an open or closed circuit.For example, this water cooling is hydraulically independent of the water cooling of the furnace vessel (11) and of the water cooling of the electrical system, e.g. the high-voltage system, the transformer, the electrode support arms, etc.

[0016] The shaft-shaped container (31) has a cuboid-shaped envelope contour, for example. The internal height in the exemplary embodiment is 10.5 meters and the width approximately 50% of this height. This width is limited by two vertically oriented wall sections, the side walls (34, 35). The length of the shaft-shaped container (31) oriented perpendicular to the aforementioned directions in the longitudinal direction (25) of the charging shaft system is 47% of the height of the shaft-shaped container (31) in the lower region. In the upper region, this length is, for example, 84% of the height of the shaft-shaped container (31). The wall section (33) facing the furnace vessel (11) is referred to below as the front wall (33). It is vertical. The wall section (36) remote from the furnace vessel is the rear wall (36). The rear wall (36) is designed as a vertical wall section (37) in the lower region. Its height is, for example, 66% of the internal height of the shaft-shaped container (31).

[0017] The upper region of the rear wall (36) is designed as a sloping impact wall (41). Its angle to the horizontal lies between 30 degrees and 45 degrees, including both end values. In the exemplary embodiment, this angle is 43 degrees. The impact wall (41) is designed such that the shaft-shaped container (31) widens towards the top. The distance from the lower edge (42) of the impact wall (41) to the front wall (33) is smaller than the distance from the upper edge (43) to the front wall (33). In the exemplary embodiment, the impact wall (41) is reinforced compared to the other wall sections (33 - 35, 37) of the shaft-shaped container (31). In the exemplary embodiment, it is twice as thick. For example, it has a water-cooled support frame (44) underneath. This is integrated into the water cooling system of the shaft-shaped container (31). On the support frame (44) sits an impact base (45), which has a support frame (46) with wear plates (47) and end plates (48).

[0018] The impact wall (41) is flat in the illustrated embodiment. It can also be curved along a single axis, for example. The axis of the curvature is then parallel to a vertical central longitudinal plane of the charging shaft system (20).

[0019] The Fig. Figure 3 shows the wear plates (47) and end plates (48) of the impact base (45). The plurality of wear plates (47) are oriented parallel to the vertical central longitudinal plane of the shaft-shaped container (31). The vertical central longitudinal plane of the shaft-shaped container (31) is spanned by a vector oriented in the vertical direction and by a vector oriented in the longitudinal direction (25) of the charging shaft system. Transverse end plates (48) are provided at the lower and upper ends of the impact base (45). If desired, the impact base (45) can be designed without the end plates (48). The material of the wear plates (47) and the end plates (48) in the exemplary embodiment is S 355 J2 G3 with the material number 1.0570. Another, more wear-resistant material for the wear plates (47) and the end plates (48) is also conceivable. In the illustrated example, the wear plates (47) and the end plates (48) have a thickness of 30 millimeters.

[0020] The Fig. 4 shows, for example, the attachment of the wear plates (47) to the support frame (46). The support frame (46) consists of closed, welded profiles (51). The individual profile (51), for example, has a rectangular cross-section, with the profile height being greater than the profile width. The profile (51) has insertion slots (52) on its upper side. Engagement hooks (53), which are welded into the wear plates (47), protrude into these insertion slots (52). The engagement hooks (53) are oriented, for example, so that their rear engagement lugs (54) point downwards. If necessary, individual wear plates (47) and / or end plates (48) can be secured by means of fixing bolts and clamping wedges penetrating these. The wear plates (47) and the end plates (48) can be replaced individually or in groups.

[0021] A shaft slide device (61) with a shaft slide (62) is arranged below the impact wall (41). The shaft slide can be moved between a first end position, in which it does not protrude into the interior (38) of the shaft-shaped container (31), and a second end position, in which it separates an upper precharging compartment (101) from a lower preheating area (102) in the interior (38). In the exemplary embodiment, the shaft slide (62) and a horizontal plane form an angle of 7 degrees. This angle is, for example, between 0 degrees and 20 degrees inclusive of both end values. The angles of inclination of the impact wall (41) and the shaft slide (62) lie in the same plane. Thus, the shaft slide (62) and the impact wall (41) form an angle of 135 degrees up to 170 degrees inclusive within the shaft-shaped container (31).

[0022] The shaft gate valve (62) is designed to be water-cooled, for example. It has a constant cross-sectional thickness of, for example, 350 millimeters. The connections for the water cooling are located on the rear side of the shaft gate valve (62), in the area of ​​the rear wall (36). The cooling circuit is connected hydraulically, for example, in parallel with the cooling circuits of the walls of the shaft-shaped container (31).

[0023] The shaft slide (62) can have a lower, for example, water-cooled support area, to which wear-resistant sheets with high thermal conductivity are attached. The fastening elements are designed, for example, as described in connection with the impact wall (41). The longitudinal direction of the sheets is oriented, for example, in the direction of travel of the shaft slide (62).

[0024] The material of the sheets is, for example, a steel with a nominal Brinell hardness of 400 HBW. In the example shown, it is an alloyed fine-grain steel with a carbon content of up to 0.32%, a silicon content of up to 0.7%, a manganese content of up to 1.6%, a phosphorus content of up to 0.025%, a chromium content of up to 2.5%, a nickel content of up to 1.5%, a molybdenum content of up to 0.6% and a boron content of up to 0.004%. The values ​​stated refer, for example, to a melt analysis of the material used. The material can be through-hardened and tempered. It is, among other things, machinable and weldable. It is also conceivable to use a different high-strength steel, e.g. 18 MnCr 4-3 or 23 MnCr4-3 with the material number 1.8714.

[0025] The shaft gate valve (62) is driven by two hydraulic cylinder-piston units (63). These are arranged on the two side walls (34, 35) of the shaft-shaped container (31). They are hydraulically synchronized with each other. The two cylinder-piston units (63) can be water-cooled. In the closed position of the shaft gate valve (62), the piston rods (64) of the cylinder-piston units (63) are retracted. To open the shaft gate valve (62), the piston rods (64) are extended relative to the cylinders (65) of the cylinder-piston units (63).

[0026] The shaft slide (62) extends from the rear wall (36) of the charging shaft system (20), facing away from the furnace vessel (11). The shaft slide (62) can be guided by means of sliding shoes in guide rails (66). These guide rails (66) continue within the shaft-shaped container (31). In the illustrated embodiment, the stroke of the shaft slide (62) is approximately 5000 millimeters. This stroke is thus greater than ten times the thickness of the shaft slide (62). The shaft slide (62) can be provided with bristles to seal against the walls of the shaft-shaped container (31).

[0027] The usable volume of the preheating area (102), for example, is one and a half times the usable volume of the precharging compartment (101). The usable volume refers to that portion of the internal volume of the shaft-shaped container (31) that is filled with feed material during operation of the charging shaft system (20). In the exemplary embodiment, the total internal volume of the precharging compartment (101), i.e., the usable volume and the unfilled areas of the precharging compartment (101), is 133 cubic meters. The internal volume of the preheating area (102) is 151 cubic meters in the exemplary embodiment.

[0028] The ceiling (39) of the shaft-shaped container (31) is largely horizontal. It is water-cooled, for example. It is closed in the area adjacent to the front wall (33). If necessary, the top of the ceiling (39) can be covered with impact-resistant sheets. The length of this area, oriented in the longitudinal direction (25) of the charging shaft system, amounts to 56% of the total length of the ceiling (39). The addition opening (27) is arranged in the area of ​​the ceiling (39) adjacent to the rear wall (36). The addition opening (27) has a rectangular cross-sectional area. It borders, for example, on the side walls (34, 35) and on the upper edge (43) of the impact wall (41). For example, the cross-sectional area of ​​the addition opening (27) amounts to 30% of the area of ​​the ceiling (39). In the exemplary embodiment, a projection of the addition opening (27) oriented in the vertical direction, i.e. in the direction of gravity, lies completely on the impact wall (41).However, it is also conceivable that at least 75% of the projected area of ​​the feed opening (27) lies on the baffle wall. The remaining part of the projected area then lies, for example, on the shaft gate valve (62).

[0029] A closure device (71) is arranged on the ceiling (39). This closure device (71) has a closure slide (72) driven by two hydraulic cylinder-piston units (73). In the exemplary embodiment, the closure slide (72) is water-cooled. For example, its water circuit is hydraulically connected in parallel with the cooling circuits of the side walls (34, 35). The closure slide (72) has, for example, block-like guide shoes with which it slides along guide rails on both sides.

[0030] The two cylinder-piston units (73) are attached to the ceiling (39) to the side of the locking slide (72). The cylinder base (74) is arranged, for example, on the rear wall (36) so that the piston rods (75) point toward the front wall (33). These piston rods (75) are retracted when the locking slide (72) is closed. The two cylinder-piston units (73) are hydraulically synchronized. This ensures that the locking slide (72), which is driven on both sides, does not jam during travel. The cylinders (76) of the cylinder-piston units (73) are water-cooled.

[0031] In the illustrated embodiment, the locking slide (72) moves over the ceiling (39) during opening. However, it is also conceivable to move the locking slide (72) in the opposite direction during opening, i.e., over the rear wall (36). The piston rods (75) of the two cylinder-piston units (73) then point in the direction away from the front wall (33).

[0032] The charging shaft system (20) has at least two suction openings (81, 91). In the exemplary embodiment, a first suction opening (81) is arranged in a side wall (34; 35) of the precharging compartment (101). It is also conceivable to provide additional suction openings (81) associated with the precharging compartment (101) in the opposite side wall (35; 34) and / or in the ceiling (39) and / or on the front wall (33).

[0033] A first suction line (82) is connected to the suction opening (81) or to the suction openings (81) of the pre-charging compartment (101). It connects the suction opening (81), for example, to a filter system as part of a suction post-treatment system. A control or regulating flap (83) is arranged in the suction line (82). If there are several suction openings (81) assigned to the pre-charging compartment (101), it is also conceivable to assign a control or regulating flap (83) to each of these suction openings (81) for controlling the suction volume flow.

[0034] In the exemplary embodiment, a second suction opening (91) is arranged in the preheating area (102) in the rear wall (36) of the shaft-shaped container (31). The distance to the shaft slide (62) corresponds, for example, to 5% of the height of the shaft-shaped container (31) below the shaft slide (62). The width of the suction opening (91) assigned to the preheating area (102) is, for example, 95% of the width of the shaft-shaped container (31). Its height is, for example, 6% of the height of the shaft-shaped container (31) below the shaft slide (62). The suction opening (91) of the preheating area (102) can also be arranged in a side wall (34; 35) of the shaft-shaped container (31). It is also conceivable to provide suction openings (91) on both side walls (34, 35). For example, an additional suction opening (91) can be provided in the rear wall (36).

[0035] An extraction duct (92) is connected to the extraction opening (91) or openings (91) of the preheating area (102). This duct has, for example, a controllable shut-off valve (93). This allows the flow of the extracted exhaust gas to be controlled or regulated. In a design with multiple extraction openings (91) assigned to the preheating area (102), these can also be individually controllable or regulated.

[0036] The cross-section of the two extraction openings (81, 91) can be identical. The cross-section of the extraction opening (81) of the precharging compartment (101) is at least 50% of the cross-section of the extraction opening (91) of the preheating area (102).

[0037] In the exemplary embodiment, the exhaust line (82) of the precharging compartment (101) and the exhaust line (92) of the preheating area (102) open into a common main exhaust line (94). This line, for example, directs the exhaust gases via a compressor station to an exhaust gas aftertreatment station. Here, for example, the exhaust gases are cleaned using a filter system and heated to a temperature above 750 degrees Celsius.

[0038] It is also conceivable to route the extraction line (82) of the precharging compartment (101) and the extraction line (92) of the preheating area (102) separately, for example, to the exhaust gas aftertreatment station. The exhaust gases can be treated separately if necessary.

[0039] The Fig. Figure 5 shows a sectional view of a variant of the charging shaft system (20) with two shaft slides (62, 67). The sectional plane of this view is perpendicular to the vertical central longitudinal plane, looking toward the rear wall (36).

[0040] One of the shaft slides (62; 67) is arranged on a side wall (34; 35) of the shaft-shaped container (31). The impact wall (41) is designed and arranged as described in connection with the first exemplary embodiment. When the shaft slides (62, 67) are closed, they move towards one another until they meet, for example in a form-fitting manner, at a butt joint (68). The butt joint (68) lies, for example, in the vertical central longitudinal plane. Its longitudinal direction, with a straight line arranged in this vertical central longitudinal plane and oriented along the impact wall (41), concludes the above-mentioned angle between an individual shaft slide (62) and the impact wall (41).

[0041] The discharge opening (21) is arranged in the lower area of ​​the charging shaft system (20). This discharge opening (21) is located below the front wall (33) on a discharge nozzle (24). The length of the discharge nozzle (24), which is water-cooled for example, is 18% of the length of the shaft interior (38) oriented in the same direction. The sliding sleeve with a sealing shield is arranged on the discharge nozzle (24), for example. The sealing shield points in the direction of the furnace vessel (11). When the electric arc furnace system (10) is in operation, the sliding sleeve rests against the furnace vessel (11) so that it closes the gap between the discharge nozzle (24) and the furnace vessel (11). The sliding sleeve together with the sealing shield is water-cooled for example.

[0042] A scrap pushing device (110) is arranged on the side of the shaft-shaped container (31) facing away from the discharge opening (21). Fig. Figure 6 shows such a scrap pushing device (110). It comprises a scrap pusher (111) that can be moved linearly by means of two hydraulically actuated cylinder-piston units (112). In a basic position, the scrap pusher (111) is located completely outside the shaft interior (38). The gap to the support frame (23) is sealed, for example, by means of a bristle seal.

[0043] From this basic position, the scrap pusher (111) can be extended relative to the support frame (23) until it extends through the discharge opening (21) into the furnace vessel (11). The stroke of the scrap pusher (111) is, for example, greater than the length of the interior space (38) of the shaft-shaped container (31) in the preheating area (102).

[0044] The scrap pusher (111), for example, has a trapezoidal-shaped thrust body (113). This thrust body (113) has a trapezoidal cross-section oriented perpendicular to its stroke direction, which widens from bottom to top. The length of the thrust body (113) is, for example, seven meters. The upper side of the thrust body (113) carries, for example, a plurality of adjacent plates (114). These plates (114) are oriented, for example, in the stroke direction (115) of the scrap pusher (111), see the Fig. 1 and Fig. 2. The plates (114) are made, for example, of the same material as the protective plates of the shaft gate valve (62). They can be attached in the same way as the wear plates (47) and the end plates (48) of the impact wall (41).

[0045] In the exemplary embodiment, the end face of the thrust body (113) has a cuboid-shaped recess, for example, which borders the lower edge of the thrust body (113). A thrust block (116) is located in this recess. The end face of the thrust block (116) amounts to a maximum of 40% of the thrust surface of the scrap pusher (111). In the exemplary embodiment, the end face of the thrust block amounts to 27% of the thrust surface of the scrap pusher (111). The length of the thrust block (116) amounts to 43% of the length of the thrust body (113).

[0046] The thrust block (116) is mounted so that it can move within the thrust body (113). For example, it can be moved relative to the thrust body (113) from a retracted position, in which the end face of the thrust block (116) lies in a common plane with the entire thrust surface, into an extended position. In the extended position, the thrust block (116) protrudes, for example, from the thrust surface by three-quarters of its length. In the exemplary embodiment, two hydraulically actuated cylinder-piston units (117) are used to drive the thrust block (116). These are controlled in a synchronized manner. Both the cylinder-piston units of the thrust block (117) and the cylinder-piston units (112) for driving the thrust body (113) can be water-cooled.

[0047] Before loading the shaft-shaped container (31), the charging shaft system (20) is positioned in an operating position on the furnace vessel (11). Any sliding sleeve present is extended and rests against the furnace vessel (11). The scrap slide gate (111) is in its retracted position. The shaft slide gate (62) and the closing gate gate (72) are closed. The shaft slide gate device (61) separates the precharging compartment (101) from the preheating area (102). If necessary, the shaft slide gate (62) can be open when restarting the electric arc furnace system (10). The extraction system for the precharging compartment (101) and the extraction system for the preheating area (102) are switched on.

[0048] The feed material is conveyed, for example, by means of several scrap baskets one after the other from a scrap yard to a loading position above the closing slide (71). Each scrap basket, for example, transports 100 tons of scrap. The closing slide (71) is opened. When the base shells of the scrap basket are opened, the scrap falls vertically downwards. It falls through the feed opening (27) and hits the impact wall (41). It slides down along the impact wall (41) onto the shaft slide (62). The shaft slide (62) therefore receives only a small portion of the impact impulse of the scrap. The scrap is distributed in the pre-charging compartment (101). The volume of the pre-charging compartment (101) is, for example, 1.2 times the nominal volume of the scrap basket, so that the entire volume conveyed by the scrap basket can be accommodated in the preheating compartment (101).The dust generated during charging is sucked away through the suction opening (81) assigned to the pre-charging compartment (101).

[0049] After loading the pre-charging compartment (101), the closing gate (71) is closed. Extraction through both extraction openings (81, 91) remains active. With the closing gate (71) still closed, the shaft gate (62) is opened. The scrap falls from the pre-charging compartment (101) into the preheating area (102). If necessary, the shaft gate (62) can be closed again immediately afterward. It then separates the pre-charging compartment (101) from the preheating area (102) within the shaft-shaped container (31).

[0050] During operation of the electric arc furnace system (10), the exhaust gases are extracted through the shaft-shaped container (31) by means of the preheating area's extraction system (102). They flow through the scrap in the preheating area (102). The gas flow is essentially diagonal from the discharge opening (21) to the extraction opening (91) of the preheating area (102). This heats the scrap evenly. The extraction volume is, for example, between 150,000 and 200,000 standard cubic meters per hour.

[0051] As soon as some of the feed material in the furnace vessel (11) has been melted, new scrap can be conveyed from the shaft-shaped container (31) into the furnace vessel (31). The scrap pushing device (110) is used for this purpose. When the pushing body (113) is extended, the bottom layer of preheated scrap is pushed through the discharge nozzle (24) into the furnace vessel (11). If the advance of the pushing body (113) is blocked, the pushing block (116) is extended relative to the pushing body (113). The pushing block (116) displaces some of the scrap directly in front of the scrap pusher (111). This reduces the resistance acting on the pushing body (113).

[0052] The scrap can be conveyed from the preheating area (101) into the furnace vessel (111) in a timed manner. For example, with each stroke of the scrap pushing device (110), a similar amount of scrap is pushed into the furnace vessel (11). The scrap pushing device (110) can thus control the progress of the melting process.

[0053] During melting and preheating, new feedstock can be loaded into the pre-charging compartment (101) with the shaft gate valve (62; 67) closed. This is done as described above. As soon as the volume of the feedstock in the preheating area (102) has dropped sufficiently, the shaft gate valve (62) is opened again, and the new feedstock is loaded from the pre-charging compartment (101) into the preheating area (102). The fill level can be monitored using sensors arranged on the outside of the shaft-shaped container (31).

[0054] Charging of the charging shaft system (20) using scrap baskets or a conveyor belt can also be performed in a timed manner. The charging intervals can be longer than the conveying intervals using the scrap pusher (110). All extraction devices are switched on during the entire process, preventing any resulting exhaust gases from escaping into the environment.

[0055] The individual embodiments can also be combined with each other. List of reference symbols: 10 Electric arc furnace system 11 Furnace vessel 20 Charging shaft system 21 Dispensing opening 22 supporting frames 23 Support structure 24 dispensing spouts 25 Charging shaft system longitudinal direction 26 Transverse direction 27 Addition opening 31 shaft-shaped container 33 Wall part of (31), front wall 34 Wall part of (31), side wall 35 Wall part of (31), side wall 36 Wall part of (31), rear wall 37 Wall section, vertical from (36) 38 Interior of (31) 39 ceiling of (31) 41 Impact wall 42 bottom edge of (41) 43 Top edge of (41) 44 Support frame 45 impact floor 46 support frames 47 wear plates, oriented in the fall line 48 wear plates, oriented in transverse direction 51 Profile 52 insertion slots 53 engagement hooks 54 rear grip lugs 61 Shaft slide device 62 shaft gate valves 63 cylinder-piston unit 64 piston rod 65 cylinders 66 guide rails 67 shaft gate valves 68 butt joint 71 locking device 72 locking slides 73 cylinder-piston units 74 Cylinder base 75 piston rods 76 cylinders 81 Extraction opening, first extraction opening 82 Suction line, first suction line 83 Control or regulating valve 91 Suction opening 92 Suction channel 93 Butterfly valve, adjustable 94 Main exhaust pipe 101 Pre-charging compartment 102 Preheating area 110 Scrap pushing device 111 scrap pusher 112 cylinder-piston unit 113 thrust bodies 114 plates 115 Stroke direction 116 thrust block 117 cylinder-piston units QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2010 045 825 A1

[0002] DE 10 2017 124 108 A1

[0003]

Claims

[1] Charging shaft system (20) with a shaft-shaped container (31) which has an actuatable closure device (71) closing a feed opening (27), a discharge opening (21) and at least one suction opening (91) associated with a preheating area (102) of the shaft-shaped container (31), wherein a shaft slide device (61) with at least one movable shaft slide (62; 67) within the shaft-shaped container (31) delimits a precharging compartment (101) from the preheating area (102), characterized by , - that at least one further suction opening (81) is assigned to the pre-charging compartment (101), - that the pre-charging compartment (101) is delimited by an impact wall (41) which has an inclination of between 30 degrees and 45 degrees, including the two end values, to a horizontal plane, wherein each vector oriented in the direction of inclination of the impact wall (41) lies in a straight line which penetrates the travel path of at least one shaft slide (62; 67) within the shaft-shaped container (31), - that a vertical projection of the feed opening (27) onto the impact wall (41) lies at least 75% on the impact wall (41). [2] Charging shaft system (20) according to claim 1, characterized by that the impact wall (41) has replaceable wear plates (47) on its side facing into the interior (38) of the shaft-shaped container (31). [3] Charging shaft system (20) according to claim 1, characterized by that the vertical projection of the addition opening (27) onto the impact wall (41) lies entirely on the impact wall (41). [4] Charging shaft system (20) according to claim 1, characterized by that the impact wall (41) and the discharge opening (21) are arranged on mutually opposite wall parts (33, 36) of the shaft-shaped container (31). [5] Charging shaft system (20) according to claim 1, characterized by that the impact wall (41) forms an angle of between 135 degrees and 170 degrees with a single shaft slide (62) or with the longitudinal direction of a butt joint (68) of two shaft slides (62, 67) within the shaft-shaped container (31). [6] Charging shaft system (20) according to claim 1, characterized by that when using a single shaft slide (62), the impact wall (41) and the shaft slide (62) are inclined in the direction of the dispensing opening (21). [7] Charging shaft system (20) according to claim 1, characterized by that all shaft valves (62, 67) and all wall parts (33 - 37) of the shaft-shaped container (31) are water-cooled. [8] Charging shaft system (20) according to claim 1, characterized by that a scrap pushing device (110) with an extendable scrap pusher (111) is arranged on the wall part (36) of the shaft-shaped container (31) facing away from the discharge opening (21). [9] Charging shaft system (20) according to claim 8, characterized by . that the extendable scrap pusher (111) has a pushing body (113) and a pushing block (116) which is movable together and relative to the latter, the pushing surface of the pushing block (116) being a maximum of 40% of the total pushing surface of the scrap pusher (111).

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