JP4442020B2 - Scrap preheating equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a scrap preheating device that preheats scrap, which is a melting raw material to be charged into a metal melting furnace, by bringing it into contact with exhaust gas discharged from the metal melting furnace.
[0002]
[Prior art]
  As a conventional preheating device of this type, for example, as disclosed in JP-A-8-54191 and JP-A-9-105590, a plurality of stages of openable and closable gates having air permeability are provided in a shaft (tower). 2 to 3 preheating chambers are formed on the upper and lower sides, the shaft wall below the lowermost preheating chamber is connected to the upper side of the uppermost preheating chamber with a shunt duct, and the uppermost preheating chamber is connected. An exhaust duct connected to the upper part of the side wall of the preheating chamber below the chamber is known.
[0003]
  The above preheating device is superior in that the exhaust gas is divided into two gas streams and the amount of heat of the exhaust gas is dispersed, so that the scrap is prevented from being locally heated and melted or oxidized. However, since it is necessary to form a plurality of preheating chambers in the upper and lower sides in the shaft, the total height of the shaft is increased, and there is a problem that it is difficult to install depending on the height of the building.
[0004]
[Problems to be solved by the invention]
  The present invention is intended to solve the above-mentioned conventional problems, and the height of the preheating device can be reduced.WithProviding a scrap preheating device that can achieve high preheating efficiency even if the retained heat of the exhaust gas or the amount of scrap varies.PurposeAnd
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, a scrap preheating apparatus according to claim 1 is characterized in that a scrap charging inlet is provided at an upper end portion and a lower portion of a shaft provided with a scrap discharge opening opposed to a scrap charging inlet of a melting furnace is provided at a lower end portion. An openable and closable gate is formed, and a preheating chamber reaching the scrap charging inlet is formed above the gate, and a shaft side wall below the gate and an upper portion of the side wall of the preheating chamber are formed.Have a damperConnected with a shunt duct and at the middle part of the side wall of the preheating chamberAcross multiple levelsIn the provided middle exhaust port,RespectivelyThrough the scrap separation chamberWith damperAn exhaust gas duct is connected.
[0006]
  And claims2The scrap preheating apparatus described is provided with a gas-permeable openable and closable gate at the lower part of the shaft provided with a scrap charging inlet at the upper end and a scrap discharge opening facing the scrap charging inlet of the melting furnace at the lower end. One preheating chamber is formed on the upper side of the gate to reach the scrape inlet, the shaft side wall on the lower side of the gate and the upper part of the side wall of the preheating chamber are connected by a shunt duct having a damper, and the preheating is performed. An exhaust gas duct having a damper is connected to an upper exhaust port provided at the upper part of the side wall of the chamber, and an exhaust gas duct having a damper is connected to an intermediate exhaust port provided in an intermediate part of the side wall of the preheating chamber via a scrap separation chamber Is connected.
[0007]
  In the present invention, the upper part of the side wall of the preheating chamber refers to the side wall portion above the upper surface position of the scrap layer when the maximum volume of scrap is charged into the preheating chamber due to fluctuations in the amount of scrap when the preheating device is used. . Also, the middle part of the side wall of the preheating chamber refers to the side wall part below the upper surface of the scrap layer when the minimum volume of scrap is charged into the preheating chamber. In the case where it is provided over the upper side, the upper middle side exhaust port may be provided in the side wall portion between the upper surface positions of both scrap layers, and in this case, this side wall portion is also included in the middle portion of the side wall of the preheating chamber. .
[0008]
  Further, in the present invention, the scrap separation chamber is a chamber having a structure for separating the scrap contained in the gas flow from the gas flow, and for example, the scrap is gravity-dropped by increasing the cross-sectional area of the flow path (decreasing the flow velocity). In addition, those based on various separation principles such as a scrap catcher type that separates scraps by inertial force by collision with a collision plate can be used.
[0009]
  Claims 1 to2According to this means, since only one preheating chamber needs to be provided in the shaft, the overall height of the shaft, and hence the height of the preheating device, can be reduced. In addition, an exhaust port is provided in the side of the scrap layer in the preheating chamber, and a shunt duct is provided. Therefore, even when the heat stored in the exhaust gas is high, the exhaust gas is shunted while the preheating chamber is single, and the scrap layer Can be preheated from both the upper and lower sides without local overheating, and the outflow of scrap from the intermediate exhaust port to the exhaust gas downstream side is prevented by the scrap separation chamber.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  Less thanBefore the description of the embodiment of the present invention,As shown in FIG. 1 and FIG.Reference example of this inventionWill be explained. In the figure, 1 is an arc furnace which is a melting furnace, and its furnace body 2 is supported by a tilting device (not shown) so as to be tiltable, and a scrap charging port 4 is provided in the furnace lid 3.
[0011]
  Reference numeral 10 denotes a scrap preheating apparatus, and 11 is a rectangular tube shaft constituting the main body, and is supported on a foundation by a traversable machine frame (not shown). Reference numeral 12 denotes a scrap inlet at the upper end of the shaft, and 13 denotes a scrap outlet at the lower end of the shaft, which is opposed to the scrap inlet 4 of the arc furnace 1 and serves also as an exhaust gas inlet from the arc furnace 1. In addition, the lower end surface of the peripheral wall has an arcuate shape along the upper end surface of the scrap input port 4.
[0012]
  Reference numeral 14 denotes a gate provided at the lower portion of the shaft 11, which is a pair of forks in which a large number of fingers are fixed to a rotating shaft arranged along the side wall of the shaft at intervals, and is driven by a driving device such as a cylinder (not shown). It is opened and closed by rotationally driving between a horizontal position (closed position) and an inclined position tilted downward (open position).
[0013]
  By installing the gate 14, a single preheating chamber 15 reaching the scrap charging inlet 12 is formed in the shaft 11. A shunt duct 16 connects the shaft side wall 11 a on the lower side of the gate 14 and the upper side wall 15 a of the preheating chamber 15. In FIG. 1, the upper surface of the scrap layer S when the maximum volume of scrap is charged into the preheating chamber 15 due to fluctuations in the amount of scrap is indicated by a solid line, and the side wall portion above the upper surface position H of the scrap layer S In addition, a shunt duct 16 is connected.
[0014]
  21A is an intermediate part exhaust port provided in the intermediate part side wall 15b of the preheating chamber 15, and is lower than the upper surface position L of the scrap layer S when the minimum volume of scrap is charged into the preheating chamber 15 indicated by a chain line in the figure. It is provided on the side wall portion on the side.
[0015]
  22A is a scrap separation chamber formed outside the intermediate exhaust port 21A. As shown in FIG. 2, the intermediate exhaust port 21A is opened at the lower part of the scrap separation chamber, and the gas channel cross-sectional area increases upward. An exhaust gas duct 25 </ b> A is connected to the upper portion of the side plate 24 formed in the shape body 23. The exhaust gas duct 25A is connected to an intake port of a blower for blowing air to a dust collector (not shown). In addition, if the connection of the exhaust gas duct to the box-like body 23 of the scrap separation chamber is a connection to the left and right side walls of the box-like body 23 as shown by a chain line in FIG. 2, the separation of the scrap is further improved.
[0016]
  Next, in the apparatus configured as described above, the scrap charged in the furnace body 2 in the arc furnace 1 is melted by arc heat, and the exhaust gas accompanying this melting is circulated in the shaft 11 of the scrap preheating apparatus 10. Thus, the scrap charged in the preheating chamber 15 is preheated. At this time, in the scrap preheating device 10, the upper surface of the scrap layer S is located at any position between the upper surface position H when the scrap amount is maximum and the upper surface position L when the scrap amount is minimum, that is, the scrap amount. Regardless of the temperature of the exhaust gas G and regardless of the heat held by the exhaust gas G, the shunt gas G of the exhaust gas G is always₁As a downward flow from the upper side of the scrap layer S through the shunt duct 16, and the remaining shunt gas G₂As an upward flow from the lower side of the scrap layer S, and the exhaust gas that has joined after scrap preheating flows out of the shaft from the intermediate exhaust port 21A through the exhaust gas duct 25A.
[0017]
  Thus, the intermediate part exhaust port 21A opens to the side part of the scrap layer S, and the scrap layer S is divided gas G by the branch duct 16.₁And split gas G₂Therefore, the scrap layer S can be efficiently preheated without local overheating, and it is not necessary to operate a damper as in each of the examples described later. Therefore, the apparatus can be manufactured simply and inexpensively, and can be suitably used especially when the maximum scrap amount (preheating chamber volume) and the amount of scrap are small. Further, as the apparatus itself, only one preheating chamber 15 needs to be provided in the shaft 11, so that the height of the shaft 11, and hence the scrap preheating apparatus 10, can be reduced.
[0018]
  During the preheating with the exhaust gas flow, scrap is accumulated near the intermediate exhaust port 21A, and the scrap layer itself acts as a filter, but some scraps such as small scrap pieces are intermediate with the exhaust gas. Although the exhaust gas flow is rapidly decelerated in the scrap separation chamber 22A and the scrap blowing force is weakened, the scrap falls by its own weight and the inclined plate of the side plate 24 of the box-like body 23 Deposited on the upper surface near the lower portion of the portion 24a. This prevents scrap from flowing into the exhaust gas duct 25A and facilitates maintenance of the duct and the downstream equipment. The scrap accumulated on the inclined plate portion 24a falls into the furnace body 2 of the arc furnace 1 together with the scrap in the preheating chamber 15 at the end of preheating and is used for melting.
[0019]
  Next, as shown in FIG.1By example, claims1Embodiments of the described invention will be described. The scrap preheating device 30 of this example isReference exampleIn the scrap preheating device 10, the damper 17 is provided in the shunt duct 16, the damper 26 A is provided in the exhaust gas duct 25 A, and the intermediate exhaust port 21 B is provided in the intermediate side wall 15 b on the upper side of the intermediate exhaust port 21 A. An exhaust gas duct 25B having a damper 26B is connected to a scrap separation chamber 22B formed outside the intermediate exhaust port 21B, and the other configuration is the same as that of the scrap preheating device 10, and therefore the same part as FIG. Are denoted by the same reference numerals, and detailed description thereof is omitted. (The same applies to other examples below.)
[0020]
  The upper middle side exhaust port 21B is located above the upper surface position L of the scrap layer S when the minimum volume of scrap is charged into the preheating chamber 15 indicated by the chain line in the drawing (however, the upper surface position H of the scrap layer). (Below the lower side). The scrap separation chamber 22B has the same structure as the scrap separation chamber 22A, and has a function of preventing the outflow of scrap into the exhaust gas duct similar to the scrap separation chamber 22A. The exhaust gas ducts 25A and 25B are shown in the figure. So that it joins downstream.
[0021]
  In the scrap preheating device 30 as well, the scrap in the preheating chamber 15 is preheated by the flow of the exhaust gas from the arc furnace 1, but generally the retained heat of the exhaust gas from the arc furnace 1 is during the operation process of the arc furnace. The heat retention of the exhaust gas is high in the oxidative refining period and the carbon injection period of the molten steel, but in other cases such as the scrap melting period, the heat retention of the exhaust gas is about 1 / of the above high retained heat. It is as low as 2 to 1/10. Further, the amount of scrap for each preheating charged into the preheating chamber 15 also varies considerably due to the change in bulk specific gravity and the like.
[0022]
  Therefore, the scrap preheating device 30 copes with the fluctuation of the heat retained in the exhaust gas and the amount of scrap as follows. That is, as indicated by a solid line in the figure, when the amount of scrap charged into the preheating chamber 15 is large and the upper surface of the scrap layer S is near the upper surface position H when the scrap amount is maximum, The dampers 17 and 26B are always open and the damper 26A is closed regardless of the level of heat held.Reference exampleAs with the split gas G of the exhaust gas G₁As a downward flow from the upper side of the scrap layer S through the shunt duct 16, and the remaining shunt gasG ₂ Is supplied as an upward flow from the lower side of the scrap layer S, and the exhaust gas that has joined after scrap preheating flows out of the shaft from the intermediate exhaust port 21B through the exhaust gas duct 25B.
[0023]
  Further, as shown by a chain line in the figure, when the amount of scrap charged into the preheating chamber 15 is small and the upper surface of the scrap layer S is near the upper surface position L when the scrap amount is minimum, the retained heat of the exhaust gas G is high. At the time, the dampers 17 and 26A are opened, the damper 26B is closed, and the shunt gas G of the exhaust gas G₁As a downward flow through the diverting duct 16 and the remaining diverted gas G₂And the exhaust gas that has joined after scrap preheating flows out of the shaft from the intermediate exhaust port 21A through the exhaust gas duct 25A as indicated by the chain arrow.
[0024]
  Similarly, when the amount of scrap is small, the damper 26B is opened, the dampers 17 and 26A are closed, and the entire amount of the exhaust gas G is supplied as an upward flow as indicated by the broken arrows when the retained heat of the exhaust gas is low. The exhaust gas after preheating the scraps flows out of the shaft from the intermediate exhaust port 21B through the exhaust gas duct 25B as indicated by the broken line arrows.
[0025]
  As a result, even when the exhaust gas is hot, the stored heat of the exhaust gas is dispersed by the split flow of the exhaust gas, and the scrap is prevented from being locally heated and melted or oxidized. Since it is heated to a state and the exhaust gas is cooled and discharged by good heat exchange, high preheating efficiency is obtained. In addition, when the retained heat of the exhaust gas G is low, the scrap layer S is divided into the diverted gas G according to the amount of scrap.₁And split gas G₂Or by the upward flow of the exhaust gas G, it is preheated without being overheated locally. Further, the scrap separation chambers 22A and 22B prevent scrap from flowing out to the dampers 26A and 26B side together with the exhaust gas, and the maintenance of these dampers becomes easy. AlsoReference exampleSince only one preheating chamber 15 needs to be provided, the height of the scrap preheating device 30 may be low.
[0026]
  The above has described the case where the upper surface of the scrap layer S is in the vicinity of the upper surface position H or L. However, when there is an upper surface in the middle, for example, when the upper surface is in the vicinity of the intermediate exhaust port 21B, the retained heat of the exhaust gas is increased. At high times, a damper operation is performed so that the exhaust gas after scrap preheating is discharged from the intermediate exhaust port 21A instead of the intermediate exhaust port 21B. The scrap can be efficiently preheated by selecting the optimum exhaust gas distribution route.
[0027]
  Next, as shown in FIGS.2By example, claims2Embodiments of the described invention will be described. The scrap preheating device 40 in this example is the first one.1In the scrap preheating device 30 of the example, an upper exhaust port 27 is provided in the upper side wall 15a of the preheating chamber, and an exhaust gas duct 28 having a damper 29 is connected to the upper exhaust port 27, and the other configuration is a scrap preheating device. 30 and the same parts as those in FIG. The exhaust gas ducts 25A, 25B, and 28 merge on the downstream side as shown in the figure, and are connected to the intake port of a blower for blowing air to a dust collector (not shown).
[0028]
  Also in this scrap preheating device 40, the scrap in the preheating chamber 15 is preheated by the flow of the exhaust gas from the arc furnace 1, but the following changes are made with respect to the above-mentioned fluctuation of the retained heat of the exhaust gas and the fluctuation of the scrap amount. To deal with. That is, first, as shown in FIGS. 4 and 5, when the amount of scrap charged in the preheating chamber 15 is large and the upper surface of the scrap layer S is near the upper surface position H, the retained heat of the exhaust gas G is high. As shown in FIG. 4, the dampers 17 and 26B are opened, the dampers 29 and 26A are closed, and a part of the shunt gas G of the exhaust gas G is closed.₁Is supplied as a downward flow into the scrap layer S from the upper side of the scrap layer S through the shunt duct 16, and the remaining shunt gas G is supplied.₂Is supplied as an upward flow from the lower side of the scrap layer S, and the exhaust gas merged after the scrap preheating is caused to flow out of the shaft from the intermediate part exhaust port 21B through the exhaust gas duct 25B.
[0029]
  As a result, even when the exhaust gas is hot, the stored heat of the exhaust gas is dispersed by the split flow of the exhaust gas, and the scrap is prevented from being locally heated and melted or oxidized. Since it is heated to a state and the exhaust gas is cooled and discharged by good heat exchange, high preheating efficiency is obtained. Also said1Similarly to the example, the scrap separation chamber 22B prevents scrap from flowing out to the damper 26B side together with the exhaust gas.
[0030]
  Similarly, when the amount of scrap is large, when the retained heat of the exhaust gas G is low, only the damper 29 is opened and the remaining dampers 17, 26A, 26B are closed as shown in FIG. It is supplied as an upward flow from the lower side of the scrap layer S, and the preheated exhaust gas flows out of the shaft from the upper exhaust port 27 through the exhaust gas duct 28.
[0031]
  Since the exhaust gas temperature is low, the scrap layer S is not locally overheated, and there is no heat loss due to the diversion into the diversion duct 16, so that the scrap can be preheated with high efficiency. Further, since the upper exhaust port 27 is located above the scrap layer S, there is no possibility of scrap flowing out from the exhaust port.
[0032]
  Next, as shown in FIG. 6, when the amount of scrap charged into the preheating chamber 15 is small and the upper surface of the scrap layer S is in the vicinity of the upper surface position L, the retained heat of the exhaust gas G is high. As shown by the solid line in the figure, the dampers 17 and 26A are opened, the dampers 29 and 26B are closed, and the shunt gas G is the same as in FIG.₁As a downward flow from the upper side of the scrap layer S through the shunt duct 16, and the remaining shunt gas G₂Are fed as an upward flow from the lower side of the scrap layer S, and the combined exhaust gas flows out of the shaft from the lower intermediate exhaust port 21A through the exhaust gas duct 25A.
[0033]
  As a result, even when the exhaust gas temperature is high, a good heating action similar to that in the case of FIG. 4 is obtained, and the scrap outflow prevention action similar to the scrap separation chamber 22B in FIG. 4 is obtained by the scrap separation chamber 22A.
[0034]
  Similarly, when the amount of scrap is small, when the retained heat of the exhaust gas G is low, only the damper 29 is opened and the remaining dampers 17, 26A, 26B are closed as shown by the broken line in FIG. As in the case, the entire amount of the exhaust gas G is supplied as an upward flow from the lower side of the scrap layer S, and flows out of the shaft from the upper exhaust port 27 through the exhaust gas duct 28.
[0035]
  As a result, the scrap can be preheated with high efficiency as in the case of FIG. When the intermediate exhaust port 21B is opened above the upper surface position L of the scrap layer S as in this example, the exhaust gas after scrap preheating flows out from the intermediate exhaust port 21B instead of the upper exhaust port 27. However, in order to store as much heat as possible in the shaft 11 after the scrap preheating, the exhaust from the upper exhaust port 27 at the top of the shaft is preferable. This improves the thermal efficiency of scrap preheating.
[0036]
  The first1Similarly to the example, when the upper surface of the scrap layer S is in the middle between the upper surface position H and the upper surface position L, for example, when the upper surface is in the vicinity of the intermediate exhaust port 21B, the above-described intermediate is performed at a time when the retained heat of the exhaust gas is high. Select the optimal exhaust gas distribution route by damper operation according to the heat stored in the exhaust gas and the amount of scrap, such as performing damper operation to discharge exhaust gas after scrap preheating from the intermediate exhaust port 21A instead of the intermediate exhaust port 21B Thus, scrap can be preheated efficiently.
[0037]
  As described above, since the intermediate exhaust ports 21A and 21B for exhaust are opened in the side surface portion of the scrap layer S and the shunt duct 16 is provided, the exhaust gas is shunted while the preheating chamber is one, and the scrap layer is formed. Preheating can be performed efficiently without local overheating, and the exhaust gas flow path is switched by operating each damper in accordance with fluctuations in the heat stored in the exhaust gas and the amount of scrap. Efficiency is obtained. Further, as the apparatus itself, it is only necessary to provide one preheating chamber 15 in the shaft 11, so that the height of the shaft 11, and hence the scrap preheating apparatus 40, can be reduced. In this example, since the upper and lower intermediate exhaust ports 21A and 21B are provided, the optimum intermediate exhaust port can be selected with respect to the variation of the scrap amount, and the adaptability to the variation of the scrap amount is high.
[0038]
  Next, as shown in FIG.3By example, claims2Another embodiment of the described invention will be described. The scrap preheating device 50 in this example is the first one.2In the scrap preheating device 40 of the example, the upper intermediate side exhaust port 21B, the scrap separation chamber 22B, the damper 26B, and the exhaust gas duct 25B in FIG. 4 are removed, and the other configurations are the same as the scrap preheating device 40. Therefore, the same parts as those in FIG.
[0039]
  In the scrap preheating device 50, the upper surface of the scrap layer S is in any position between the upper surface position H when the scrap amount is maximum and the upper surface position L when the scrap amount is minimum, that is, it is related to the scrap amount. In the period when the retained heat of the exhaust gas G is high, the dampers 17 and 26A are opened and the damper 29 is closed.Reference exampleAs with the split gas G of the exhaust gas G₁As a downward flow from the upper side of the scrap layer S through the shunt duct 16, and the remaining shunt gas G₂From the lower side of the scrap layer S is supplied as a downward flow, and the exhaust gas merged after scrap preheating flows out of the shaft from the intermediate exhaust port 21A through the exhaust gas duct 25A.
[0040]
  Similarly, regardless of the amount of scrap in the preheating chamber 15, when the retained heat of the exhaust gas is low, only the damper 29 is opened and the remaining dampers 17, 26 </ b> A are closed, as indicated by broken line arrows.Reference exampleSimilarly, the entire amount of the exhaust gas G is supplied as an upward flow from the lower side of the scrap layer S, and the exhaust gas after scrap preheating flows out of the shaft from the upper exhaust port 27 through the exhaust gas duct 28.
[0041]
  Thus, in this example, by switching the exhaust gas flow path by operating each damper according to the level of the retained heat of the exhaust gas, high preheating efficiency can be obtained even if the retained heat fluctuates, especially in the amount of scrap. Regardless of the above, it is only necessary to operate the damper, so that the operation of the damper is easy. The second2Since only one preheating chamber 15 needs to be provided as in the example, the height of the scrap preheating device 50 may be low.
[0042]
  The present invention is not limited to the above examples. For example, as a scrap separation chamber, as shown in FIG. 8, a baffle plate 61 is provided in a box-like body 23 of the scrap separation chamber of each of the above examples. , A scrap separation chamber 60 that further ensures the collection of scrap, and as shown in FIG. 9, a collision plate 72 is provided in a suspended manner in the casing 71, and an open / close bottom plate 74 is provided at the bottom of the lower scrap storage portion 73, Various types such as a scrap catcher type scrap separation chamber 70 connected to the intermediate side wall 15b by a connecting duct 75 and a scrap return pipe 76 can be used. The scrap separation chamber may be integrally attached to the intermediate side wall 15b as in the above examples, or may be connected to the intermediate side wall 15b via a duct as in the scrap separation chamber 70.
[0043]
  Further, the gate may be of other types such as the above-mentioned swinging fork type, or a direct acting fork type that moves in the horizontal direction and is inserted into and pulled out from the tower body. Further, the melting furnace may be other than the above-mentioned arc furnace, and if it is not necessary to traverse the tower depending on the type and structure of the melting furnace, the tower may be fixed on the foundation. .
[0044]
【The invention's effect】
  As described above, according to the present invention, since only one preheating chamber is provided in the shaft, the overall height of the shaft, and hence the height of the scrap preheating device, can be reduced, and installation in a low building is also possible. In addition, even when the retained heat of the exhaust gas is high, it is possible to preheat the scrap layer from both the upper and lower sides without local overheating by diverting the exhaust gas while having a single preheating chamber.In addition to being able toEven if the retained heat of the exhaust gas or the amount of scrap fluctuates, high preheating efficiency can be obtained by switching the exhaust gas distribution path by operating the damper.
[0045]
  In addition to the above effects, the claims2In the invention describedAccording to the upper exhaustTherefore, when the exhaust gas holding heat is low, it is not necessary to use a diverting duct regardless of the amount of scrap, and heat loss due to the diverting into the diverting duct is eliminated, and higher preheating efficiency is obtained.
[Brief description of the drawings]
FIG. 1 of the present inventionReference exampleIt is a longitudinal cross-sectional view of the scrap preheating apparatus which shows.
FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG.
FIG. 3 shows the first embodiment of the present invention.1It is a longitudinal cross-sectional view of the scrap preheating apparatus which shows an example.
FIG. 4 shows the first embodiment of the present invention.2It is a longitudinal cross-sectional view of the scrap preheating apparatus which shows an example.
5 is a longitudinal sectional view showing a usage state of the scrap preheating device of FIG.
6 is a longitudinal sectional view showing another usage state of the scrap preheating device of FIG. 4; FIG.
FIG. 7 shows the first embodiment of the present invention.3It is a longitudinal cross-sectional view of the scrap preheating apparatus which shows an example.
FIG. 8 is a longitudinal sectional view showing another embodiment of the scrap separation chamber according to the present invention.
FIG. 9 is a longitudinal sectional view showing still another embodiment of the scrap separation chamber according to the present invention.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Arc furnace (melting furnace), 10 ... Scrap preheating apparatus, 11 ... Shaft, 11a ... Shaft side wall, 12 ... Scrap charging inlet, 13 ... Scrap discharge port, 14 ... Gate, 15 ... Preheating chamber, 15a ... Upper side wall, 15b ... Intermediate side wall, 16 ... Shunt duct, 17 ... Damper, 21A ... Intermediate exhaust port, 21B ... Intermediate exhaust port, 22A ... Scrap separation chamber, 22B ... Scrap separation chamber, 25A ... Exhaust gas duct, 25B ... Exhaust gas duct 26A ... damper, 26B ... damper, 27 ... upper exhaust port, 28 ... exhaust gas duct, 29 ... damper, 30 ... scrap preheating device, 40 ... scrap preheating device, 50 ... scrap preheating device, 60 ... scrap separation chamber, 70 ... Scrap separation room.

Claims (2)

  An openable and closable gate is provided at the lower part of the shaft having a scrap loading inlet at the upper end and a scrap discharge port facing the scrap charging inlet of the melting furnace at the lower end, and the scrap is disposed above the gate. A preheating chamber is formed to reach the loading port, and the shaft side wall on the lower side of the gate and the upper portion of the side wall of the preheating chamber are connected by a shunt duct having a damper, and in the middle portion of the side wall of the preheating chamber. A scrap preheating apparatus, wherein an exhaust gas duct having a damper is connected to an intermediate exhaust port provided over a plurality of stages via a scrap separation chamber.   An openable and closable gate is provided at the lower part of the shaft having a scrap loading inlet at the upper end and a scrap discharge port facing the scrap charging inlet of the melting furnace at the lower end, and the scrap is disposed above the gate. A preheating chamber is formed to reach the charging port, and the shaft side wall on the lower side of the gate and the upper portion of the side wall of the preheating chamber are connected by a shunt duct having a damper and provided on the upper portion of the side wall of the preheating chamber. An exhaust gas duct having a damper is connected to the upper exhaust port, and an exhaust gas duct having a damper is connected to an intermediate exhaust port provided in an intermediate part of the side wall of the preheating chamber via a scrap separation chamber. Scrap preheating equipment.

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