CN111201332B

CN111201332B - Scrap preheating device for a furnace and method for preheating scrap

Info

Publication number: CN111201332B
Application number: CN201880066331.1A
Authority: CN
Inventors: 哈拉尔德·霍尔兹格鲁伯; 里卡尔多·戈塔尔迪; 约阿希姆·埃勒; 米凯·马纳佐; 汉斯·乔格·克拉斯尼格
Original assignee: Intich Casting Technology Co ltd
Current assignee: Intich Casting Technology Co ltd
Priority date: 2017-10-17
Filing date: 2018-09-19
Publication date: 2022-05-17
Anticipated expiration: 2038-09-19
Also published as: EP3697935A1; WO2019076567A1; CN111201332A; DE102017124108A1

Abstract

The invention relates to a scrap preheating device (10) for a furnace (50), comprising an at least substantially horizontally arranged conveying device (15), for feeding the scrap (5) between an input zone (17) for the scrap (5) into the conveyor (15) and a transfer zone (19) for the scrap (5) into the furnace (50), wherein the conveying device (15) is arranged at least between the input region (17) and the transfer region (19) in a scrap preheating housing (12) having an at least substantially closed cross section, or the conveying device (15) is covered by a scrap preheating housing (12) on the side of the conveying section facing the scrap (5), the scrap preheating device (10) further having an extraction device (48) for extracting exhaust gases from the furnace (50), wherein the extraction device (48) is designed to guide the exhaust gas out of the transfer region (19) in the direction of the inlet region (17).

Description

Scrap preheating device for a furnace and method for preheating scrap

Technical Field

The present invention relates to a scrap preheating arrangement for a furnace according to the preamble of claim 1. The invention also relates to a method for preheating scrap for a furnace, in particular by using the scrap preheating device according to the invention.

Background

Different apparatuses are known from the prior art which use the hot exhaust gases of a melting furnace, in particular an electric arc furnace, for preheating scrap for producing a melt in the melting furnace. Among these, devices are known which have a shaft for conveying the waste material, which is arranged substantially vertically above the furnace, through which the exhaust gases or waste heat pass when rising and thus ensure good utilization of the waste heat. However, the relatively high height of such a plant consisting of a furnace and a scrap preheating device is disadvantageous. Another drawback of this plant is that the scrap fed into the furnace in a weight-uncontrolled or discontinuous manner is compressed, which means that difficulties can arise during transport, in particular wedging the scrap in a scrap preheating device, which can lead to an interruption of the scrap transport.

Furthermore, general waste preheating devices are known in the prior art, which use the so-called "Con-Steel" method and are implemented with different designs. Such a scrap preheating device known from DE 102008037111 a1 is characterized by a horizontally arranged conveyor belt or horizontally arranged conveyor means for continuously feeding scrap in the direction of the furnace inside a tubular scrap preheating housing. A recess is formed in the upper wall of the scrap preheating housing between an input area for scrap onto the conveyor and a transfer area for scrap from the conveyor into the furnace, the recess forming an intake area connected to a suction device for drawing off exhaust gases from the furnace. In this case, it is disadvantageous that the cross section of the scrap preheating housing above the conveyor is not completely filled with scrap, since this can lead to the scrap becoming jammed or jammed in the scrap preheating housing, for example in the abovementioned air intake region, which can lead to jamming of the conveyor as known from the first-mentioned design. The waste material therefore only fills a partial section of the waste material preheating housing and the exhaust gas sucked in by the extraction device is guided between the upper side of the waste material and the waste material preheating housing over substantially a partial length of the section between the feed region and the transfer region. The efficiency of the plant is relatively low, since the hot exhaust gases are only effectively connected to the upper region of the waste material, while the region of the waste material facing the conveyor is at least substantially not preheated by the waste heat or hot exhaust gases.

Another prerequisite for the construction or use of such a waste preheating device is that no exhaust gases leave the area of the waste preheating device in an uncontrolled manner. In many cases, the exhaust gases escape as a result of leakage from the waste preheating device and must be (thermally) post-treated, since not only odorous substances are produced during the preheating of the waste, but carbon monoxide is also produced from the paint or oil in the waste, which carbon monoxide cannot be released into the atmosphere in accordance with regulatory regulations. Thus, post-combustion of carbon monoxide in a so-called post-combustion chamber is forced. The odorous substances are combusted in the post-combustion chamber at a temperature of 700 ℃ to 800 ℃. Furthermore, it has to be noted that air with normal ambient temperature, which enters the scrap preheating device due to leakage, must be heated to the above-mentioned 700 to 800 ℃ in the post-combustion chamber or at an earlier stage together with the exhaust gases. Thus, leakage in the apparatus results in a further reduction in the efficiency of the scrap preheating arrangement, due to the increased energy required to ensure the required temperature in the post-combustion chamber.

Disclosure of Invention

The advantage of the scrap preheating device for furnaces according to the invention, comprising the features of claim 1, is that it has the advantages of both the above-mentioned designs (vertical feed shaft and substantially horizontal continuous transport according to the "Con-Steel" method) without its typical drawbacks. In particular, the scrap preheating device according to the invention makes particularly good use of the (hot) exhaust gases generated in the furnace for scrap preheating and is therefore particularly efficient. In addition, the scrap preheating device according to the invention allows an effective connection to be established between the hot exhaust gases used for heating the scrap and the scrap, so that the scrap is heated completely or uniformly. Uniform heating is achieved in that the cross section of the scrap preheating housing can be completely filled with scrap, since the scrap is not compressed when being continuously conveyed by the conveyor, which is arranged in particular in an inclined manner, and therefore does not tend to get stuck in the scrap preheating housing and block the conveyor.

According to the invention, the scrap preheating device has an extraction device which comprises at least one air inlet region which is arranged on the side of the inlet region facing away from the transfer region at the end region of one end of the scrap preheating housing and which at least partially, preferably at least substantially, acts on the cross section of the scrap preheating housing, and/or at least one air inlet region is arranged in the region between the inlet region and the transfer region, preferably in the region of the inlet region at two opposite side walls of the scrap preheater, the air inlet region extending in the region of the side walls at least partially, preferably substantially, over the entire height of the scrap preheating housing.

In summary, the scrap preheating device according to the invention is contrary to the general prior art and is characterized in that the hot exhaust gases are guided laterally by an air inlet region arranged laterally in the scrap preheating housing region not only along the upper part of the scrap conveyed in the scrap preheating housing but preferably along the entire cross-sectional area of the scrap, or additionally or alternatively along the entire height of the scrap. In addition, the arrangement of the air inlet region according to the invention allows the cross section of the scrap preheating housing to be filled as completely or as technically as possible with scrap, without this having a negative effect on the function of scrap heating or scrap conveying. Furthermore, the waste material is heated over the entire conveying length on the conveying device, so that the waste material is exposed to the exhaust gas for the longest time.

Advantageous embodiments of the scrap preheating device for a furnace according to the invention are disclosed in the dependent claims. All combinations of at least two of the features disclosed in the claims, the description and/or the drawings form part of the scope of the invention.

In a preferred structural configuration of the conveyor, the conveyor has a bottom comprising sheet parts which are arranged so as to be movable relative to one another in the conveying direction of the waste material. Such a conveyor is characterized in particular in that the scrap is drawn out in the direction of the furnace by friction (only) in the region of the bottom of the conveyor, whereby jamming or jamming of the scrap in the side wall and top regions of the scrap preheating housing is avoided in particular, and the volume is not reduced and the scrap is not compressed at any time during the transport process. This allows or facilitates the filling of the entire cross section of the scrap preheating housing in particular with scrap. Furthermore, as the cross-sectional area of the scrap preheating housing between the input area of the scrap and the transfer area of the scrap into the furnace increases, the tendency of the scrap to become stuck by the walls of the scrap preheating housing is reduced.

The feeding of the scrap in the direction of the furnace and the overall filling of the cross-section of the scrap preheating housing above the conveying device for the optimal utilization of the hot exhaust gases can be improved by inclining the bottom of the conveying device with respect to the horizontal, preferably by at least 5 °, preferably by an angle between 5 ° and 15 °, whereby the transport of the scrap is supported by the effect of gravity.

Since the (hot) exhaust gases of the furnace act on the scrap at least substantially over the entire cross section of the scrap in the scrap preheating housing, heat transfer of the scrap to the bottom region of the conveyor in the transition region of the scrap also takes place. In order to avoid negative effects on the functionality of the conveyor or thermal overloading of the conveyor in the bottom region, provision is also made for the sheet part, in a conveyor with sheet parts, to have a cooling device which cools the sheet part on the side facing away from the scrap.

In order to make it easy for the melting furnace to be tilted for pouring out the melt after the process of filling the melting furnace with scrap is finished, the invention provides in addition that the conveyor together with the parts surrounding the conveyor are arranged additionally longitudinally displaceable, in particular by arranging the conveyor and the scrap preheating housing on the roller part. Thus, the conveyor may be arranged at a greater distance relative to the furnace so that when the furnace is tilted, it is not prevented from the desired tilting by the conveyor or the scrap preheating housing.

Another aspect of the scrap preheating device according to the invention relates to an input area in which the scrap is fed into the area of the conveyor or the scrap preheating housing. According to a preferred embodiment of the invention, the input region is realized in the form of a gate such that the entry of ambient air in the direction of the waste preheating housing can be blocked by at least one blocking element. This design improves the efficiency of the scrap preheating device in particular by the fact that no undesirable ambient air (which is cold relative to the hot exhaust gases being drawn in) enters the area of the scrap preheating housing or conveyor, where it can mix with the hot exhaust gases and thus reduce the temperature. The formation of the input area in the manner of a gate can be achieved by a plurality of plates or gates that are movable relative to each other or, for example, by a screw conveyor for the waste material that is isolated from the environment at its periphery.

In order to prevent hot exhaust gases from entering the environment from the region of the conveyor and ambient air from the outside from entering the region of the conveyor or the waste preheating housing and thus causing a reduction in efficiency by mixing with the hot exhaust gases, the invention further proposes that the region of the conveyor below the sheet component is sealed by means of a housing which is sealed against the environment in order to prevent the entry of ambient air.

In order to avoid the waste material being conveyed towards the extraction device, in particular when the extraction device is arranged such that the exhaust gas is sucked in over the entire cross section of the waste material in the region of the waste material preheating housing, the invention further proposes that the waste material preheating housing has, on the side of the waste material preheating housing facing away from the transfer region of the waste material, a gas-permeable rear wall (for example in the form of a perforated plate or the like) which is arranged in alignment with the intake region of the extraction device.

An additional improvement of the transfer of the scrap in the direction of the furnace can be achieved if transfer means for the scrap, in particular in the form of slides, which can be operated independently of the transfer device, are provided in the region of the input area. The slide can be realized in particular by the aforementioned rear wall or orifice plate.

In order to allow the scrap to enter the scrap preheating housing or the area of the conveying device only by means of gravity, so that the scrap does not have to be conveyed by means of a further conveying device, the invention provides that the input area for the scrap is arranged on the top side of the scrap preheating housing at an end area opposite the transfer area.

In order to avoid unwanted further scrap entering the furnace, in particular entering the scrap furnace towards the end of the filling of the furnace, and in order to seal the conveyor or the scrap preheating housing towards the furnace when it is removed from the furnace so that the furnace can be pivoted or tilted in order to pour out the melt, a further advantageous embodiment of the invention provides that the transfer area of the conveyor or the scrap preheating housing is formed so as to be closable in the direction of the furnace by means of a blocking element.

In order to thermally after-treat or treat the exhaust gases which are drawn in from the furnace via the extraction device and which may be contaminated with scrap, so that said exhaust gases can subsequently be released into the surrounding atmosphere, one embodiment of the invention provides that the exhaust gases which are drawn through the scrap by means of the extraction device can be provided to the post-combustion device by means of the extraction device after flowing through the scrap.

In a particularly preferred embodiment of the last-mentioned variant, the post-combustion device is connected to the upper region of the furnace via a manifold, and the mixing ratio of the exhaust gases entering from the manifold of the furnace and additionally entering the post-combustion device via the extraction device and the temperature of the exhaust gases in the post-combustion chamber can be adjusted by means of a flow guide device, in particular in the form of an adjustable baffle.

The invention furthermore relates to a method for preheating scrap for a furnace, in particular by using the aforementioned scrap preheating device according to the invention, wherein the scrap is fed in an input area to a conveyor which conveys the scrap at least substantially horizontally, the conveyor heating the scrap along a conveying path between the input area and a transfer area into the furnace by using hot exhaust gases extracted from the furnace. The method according to the invention is characterized in that the exhaust gases are extracted on the side of the input area facing away from the transfer area via at least a part of the cross section of the scrap preheating housing extending perpendicularly to the conveying direction of the scrap in the conveyor and/or in the area of two opposite side walls of the scrap preheating housing surrounding the conveyor.

A particularly preferred embodiment of the aforementioned method is characterized in that the entire cross section of the scrap preheating housing is at least substantially completely filled with scrap and the scrap is conveyed continuously.

Another preferred feature of the method is that the scrap is transferred back by reversing the direction of transfer at the end of the furnace filling, so as to remove any scrap located in the transition zone from said zone to the furnace, and so as to facilitate the closing of the scrap preheating enclosure and the furnace by respective closing members.

Furthermore, the method for preheating scrap by using a scrap preheating device according to the present invention is characterized in that the scrap does not tend to be compressed nor to be clogged during the continuous conveyance of the scrap.

Further advantages, features and details of the invention can be taken from the following description of preferred embodiments and the accompanying drawings.

Drawings

In the drawings:

FIG. 1 is a simplified longitudinal section through an apparatus for melting metal, the apparatus comprising a furnace having a scrap preheating device connected thereto and a post-combustion chamber visible in the background,

FIG. 2 is a section in the region of the conveying device of the scrap preheating device according to FIG. 1, an

Fig. 3 is a top view of the transfer device with the sheet member, viewed in the direction of arrow III in fig. 2.

Detailed Description

In the drawings, the same components and components having the same functions are denoted by the same reference numerals.

Fig. 1 shows a highly simplified example of an apparatus 100 for producing a melt 1 consisting of metal in a furnace 50. In a manner known per se, the furnace 50 is formed with an inner chamber 51 and can be pivoted or tilted about an axis of rotation 52, which axis of rotation 52 extends in the illustration of fig. 1 perpendicularly to the drawing of fig. 1, in order to subsequently treat the melt 1 produced in the inner chamber 51 of the furnace 50 by pouring it out of the furnace 50 in the region of an outlet (not shown) of the furnace 50. Furthermore, two of three electrodes 55 are shown connected to a voltage source (not shown), said electrodes 55 being used to generate the energy needed to liquefy the metal. The furnace 50 also has an upper region 58, which upper region 58 is formed in a dome-like manner and is connected to a post-combustion chamber 60 via a manifold 59.

The melt 1 is produced by adding scrap 5 which is melted by means of the electrodes 55, the scrap 5 being fed to the melting furnace 50 by means of the scrap preheating device 10 according to the invention.

As is shown schematically in fig. 1 to 3, the scrap preheating device 10 has a tubular scrap preheating housing 12, which scrap preheating housing 12 has, for example, a rectangular cross section and covers the top side of an at least substantially horizontally arranged conveyor 15. As can be seen from fig. 1, the scrap preheating housing 12 is substantially linear, and in the exemplary embodiment shown, the height h of the scrap preheating housing 12, and thus the cross-sectional area of the scrap preheating housing 12 (assuming that the scrap preheating housing 12 has a constant width), increases in the direction of entry of the scrap 5 into the input area 17 of the scrap preheating housing 12 towards entry of the scrap 5 into the transfer area 19 of the furnace 50.

As can also be seen from fig. 1, in the transfer zone 19, the cross section of the scrap preheating housing 12 or of the conveying device 15 can be closed or opened by means of a locking slide 22 which is movable in the direction of the double arrow 21.

It should also be mentioned that the melting furnace 50 also has an opening 23 in the region of the transfer region 19, which opening can be closed by means of components not shown, in order to transfer the scrap 5 into the melting furnace 50 and to allow the melting furnace 50 to be sealed in this region with the opening 23 closed.

Furthermore, fig. 1 and 2 show that the conveyor 15 is arranged together with the scrap preheating housing 12 on the roller part 25 so as to be displaceable in the direction of the double-headed arrow 26 in order to arrange the conveyor 15 or the scrap preheating housing 12 at a greater distance relative to the furnace when the process of filling the furnace 50 with scrap 5 is completed, so that the furnace 50 can be tilted about the axis of rotation 52 in order to remove the melt 1. For this purpose, the scrap preheating housing 12 or the conveying device 15, which are connected to one another in terms of their construction, are connected to the regulating drive 28.

The input area 17 of the scrap preheating device 10 for the scrap 5 to enter is arranged on its top side 31 on the side opposite the transport area 19 at the end area 30 of one end of the scrap preheating housing 12, and said input area 17 has a feed shaft 32 which projects vertically upwards and can be closed by means of two

transverse slides

36, 38 which are arranged above and parallel to each other and can be moved independently of each other in the direction of the double-headed arrow 34, said transverse slides 36, 38 acting as locking or blocking means.

As can be seen from fig. 1, a specific quantity 6 of scrap 5 is arranged between the two

transverse slides

36, 38, which is moved by release of the lower transverse slide 36 via the feed shaft 32 from the position shown in fig. 1 into the area of the scrap preheating housing 12 or the conveyor 15.

It should also be mentioned that instead of the two

transverse slides

36, 38, other means for feeding the scrap 5 into the scrap preheating housing 12 or into the region of the conveyor 15 may also be provided, for example a combination of a conveyor belt and a screw conveyor or the like. In order to realize such a feeding device, it is important that the feed shaft 32 or the scrap preheating housing 12 is formed in a form as sealed as possible to prevent the entry of ambient air during the feeding of the scrap 5 into the scrap preheating housing 12.

At the end region 30 of the end of the scrap preheating housing 12 opposite the transport region 19, an air inlet region 42 is arranged, which air inlet region 42 is arranged in operative connection with the cross section of the scrap preheating housing 12, for example by means of an air-permeable part, such as an orifice plate 44.

Importantly, the intake area 42 is arranged in such a way that: which is at least partially, preferably largely, particularly preferably completely, aligned with the scrap 5 conveyed on the conveyor 15 inside the scrap preheating housing 12, or the air inlet region 42 acts on a cross section of the scrap 5 perpendicular to the at least substantially horizontal conveying direction 70 of the scrap 5 inside the scrap preheating housing 12. For this purpose, the perforated plate 44 or the air inlet region 42 extends from the level of the bottom region or the conveying level of the conveyor 15 to the region in which the feed shaft 32 extends upward from the scrap preheating housing 12. In the ideal case, therefore, the intake region 42 has a height in the end region 30 which corresponds to the height h of the scrap preheating housing 12 in the end region 30.

Intake area 42 is coupled to an extraction device 48 via an intake manifold 46. Furthermore, an adjustable baffle 49 is arranged in the intake manifold 46 in order to adjust the amount of hot exhaust gases drawn in by the extraction device 48 from the inner chamber 51 of the furnace 50 via the cross section of the scrap preheating housing 12. Furthermore, the extracted exhaust gases are moved from the extraction device 48 into the post combustion chamber 60 via the feed manifold 62 or the feed line, wherein an adjustable baffle 64 is arranged in the manifold 59 in an exemplary manner, so that the mixing ratio between the exhaust gases directly from the furnace 50 via the manifold 59 into the region of the post combustion chamber 60 and the exhaust gases via the extraction device 48 and the feed manifold 62 into the region of the post combustion chamber 60 is adjustable.

According to an alternative embodiment, external air for tempering exhaust gases heated in the post-combustion chamber 60 by means of a heating device, not shown, to a temperature between 700 ℃ and 800 ℃ is fed into the region of the manifold 62 via a fresh air intake 66 with an adjustable baffle 68.

As can be seen in particular from the schematic illustration in fig. 2 and 3, the conveyor 15 arranged next to the post-combustion chamber 60 has a plurality of sheet parts 72, which sheet parts 72 are arranged parallel to one another and in the longitudinal direction or conveying direction 70 of the scrap 5 to form a bottom 73, said sheet parts 72 being made of wear-resistant steel. Twelve slice members 72 are shown in an exemplary manner. The sheet members 72 form a pusher plate and extend over the entire length of the conveyor 15, each sheet member 72 having the same width b, for example 10cm to 30 cm. The sets of slice members 72 may be moved simultaneously and synchronously by means of respective drives (not shown). The principle of the transport of the waste 5 by means of the sheet part 72 is explained below: for example, assume that twelve sheet members 72 are arranged next to each other. First, the first, fourth, seventh and tenth sheet layer components 72 are pulled back against the transport direction 70 by a distance of, for example, 30 cm. Then, the second, fifth, eighth and eleventh sheet parts 72 are pulled back by the same distance (30 cm). Subsequently, the third, sixth, ninth and twelfth sheet members 72 were pulled back by the same distance (30 cm). The transfer process of the scrap 5 is now performed by pushing all twelve sheet members 72 simultaneously forward the same distance (30cm) in the transfer direction 70.

It is also mentioned that the level of the conveyor 15, i.e. the sheet part 72, is arranged inclined with respect to the horizontal by an angle alpha of at least 5 deg., preferably between 5 deg. and 15 deg.. However, such an angle α should still be constituted by an at least substantially horizontal arrangement of the conveying means 15. This is in particular in relation to or in comparison with a conveyor, wherein the conveyor extends at least substantially vertically or the waste 5 is conveyed by the action of gravity of the waste 5.

According to fig. 2, below the scrap preheating housing 12, the sheet component 72 is surrounded by a housing 74, which housing 74 may be part of the scrap preheating housing 12, in order to avoid hot exhaust gases from the scrap preheating housing 12 leaking via the sheet component 72 to the external environment and to avoid air from the external environment entering the area of the scrap preheating housing 12 via the sheet component 72. Fig. 2 furthermore shows that the sheet parts 72 made of heat-resistant steel are each connected on the bottom side facing away from the scrap preheating housing 12 to a cooling device 76, which cooling device 76 has, for example, cooling channels (not shown in fig. 2) through which cooling water flows.

In order to transport the scrap 5 from the input area 17 towards the transfer area 19 or the transfer device 15, a slide 78 may also be provided, said slide 78 being arranged to be movable and to transfer the scrap 5 towards the furnace 50. Alternatively, the orifice plate 44 may also be formed as a slider.

Fig. 2 additionally optionally shows the possibility of arranging the scrap preheating housing 12 in operative connection with the extraction device 48 in the region of its two

opposite side walls

80, 82 via correspondingly formed intake regions 84. The

side walls

80, 82 are formed in a gas-permeable manner in the region of the intake region 84, for example by means of perforated plates. It is important that the air inlet region 84 is arranged at least substantially over the entire height h of the scrap preheating housing 12 or over the height of the scrap 5 conveyed in the scrap preheating housing 12, the air inlet region 84 also preferably being arranged in the region of the feed region 17 for the scrap 5 in the scrap preheating compartment 12.

Furthermore, fig. 1 shows that, when the scrap 5 is fed into the furnace 50, at least almost the entire cross section of the scrap preheating housing 12 is filled with the scrap 5 above the conveying device 15, the hot exhaust gases drawn in from the region of the furnace 50 via the extraction device 48 thus also act on the scrap 5 over the entire cross section of the scrap 5 in the scrap preheating housing 12.

The aforementioned apparatus 100 or waste preheating device 10 may be changed or modified in various ways without departing from the idea of the present invention. As shown optionally in fig. 2, a further conveyor 90 may be arranged in particular at least in the transition region between the feed shaft 32 and the scrap preheating housing 12, in particular in the region of the

side walls

80, 82. The further conveyor 90 is preferably arranged in the upper region of the scrap preheating housing 12 and can be formed in correspondence with the conveyor 15 comprising the sheet part 72 or realized in the form of a conveyor belt, slide or the like.

When the further conveyor 90 is in operation, it is necessary to convey the waste 5 coming from the feed shaft 32 against the conveying direction 70 of the conveyor 15, preferably continuously. By conveying the scrap 5 back in the upper region of the scrap preheating housing 12, the further conveying device 90 reliably prevents the scrap 5 from becoming jammed and compressed in the transition region from the feed shaft 32 into the scrap preheating housing 12, when the scrap 5 is simultaneously conveyed by the conveying device 15 in the lower region of the scrap preheating housing 12.

Reference numerals

1 melt

5 waste material

6 number of

10 waste material preheating device

12 waste preheating shell

15 conveying device

17 input area

19 transfer area

21 double arrow

22 locking slide

23 opening

25 stick component

26 double arrow

28 Adjustable drive

30 end region

31 top side

32 feed shaft

34 double-headed arrow

36. 38 transverse sliding member

42 air intake zone

44 orifice plate

46 intake manifold

48 extraction device

49 baffle

50 smelting furnace

51 inner chamber

52 axis of rotation

55 electrode

Region 58

59 manifold

60 post combustion chamber

62 feed manifold

64 baffle

66 fresh air intake

68 baffle

70 conveying direction

72 sheet component

73 bottom

74 casing

76 Cooling device

78 sliding part

80. 82 side wall

84 air intake zone

90 conveying device

100 device

h height

b width of

Angle alpha

Claims

1. A scrap preheating device (10) for a melting furnace (50) having a substantially horizontally arranged conveyor (15) for feeding scrap (5) between an input area (17) where the scrap (5) enters the conveyor (15) and a transfer area (19) where the scrap (5) enters the melting furnace (50) from the conveyor (15), the conveyor (15) being arranged at least between the input area (17) and the transfer area (19) in a scrap preheating housing (12) having a substantially closed cross-section, or the conveyor (15) being covered by a scrap preheating housing (12) on a side facing a transfer section of the scrap (5), and the scrap preheating device (10) having an extraction device (48) for extracting exhaust gases from the melting furnace (50), the extraction device (48) being formed for guiding the exhaust gases out of the input area (17) in the direction -said transfer area (19),

characterized in that the extraction device (48) is connected to at least one air inlet region (42), which air inlet region (42) is arranged on the side of the inlet region (17) facing away from the transfer region (19) at an end region (30) of one end of the scrap preheating housing (12) and acts at least partially substantially on the cross section of the scrap preheating housing (12), and/or in that at least one air inlet region (84) is arranged in the region of two opposite side walls (80, 82) of the scrap preheating housing (12) in the region between the inlet region (17) and the transfer region (19), which air inlet region (84) extends at least partially substantially over the entire height of the scrap preheating housing (12) in the region of the side walls (80, 82).

2. The scrap preheating device according to claim 1, characterized in that at least one air inlet region (84) is arranged in the input region (17) in the region of two opposite side walls (80, 82) of the scrap preheating housing (12),

the conveying device (15) has a bottom (73) comprising sheet parts (72), the sheet parts (72) being parallel in a conveying direction (70) and arranged in a relatively movable manner along the conveying direction (70) or against the conveying direction (70).

3. The scrap preheating apparatus according to claim 2, characterized in that the bottom (73) of the conveyor (15) is arranged inclined at an angle of at least 5 ° with respect to the horizontal.

4. A scrap preheating arrangement according to claim 3, characterized in that the bottom (73) of the conveyor (15) is arranged inclined at an angle of between 5 ° and 15 ° with respect to the horizontal.

5. A scrap preheating arrangement according to any one of claims 1-3, characterized in that the cross-section of the scrap preheating housing (12) increases at least partly continuously from the input area (17) in the direction of the transfer area (19) by increasing the height of the scrap preheating housing (12) above the conveyor (15).

6. The scrap preheating device according to any one of claims 2 to 4, characterized in that the sheet part (72) can be cooled by means of at least one cooling device (76) on the side of the conveying section facing away from the scrap (5).

7. The scrap pre-heating apparatus according to any of claims 1 to 4,

characterized in that the conveyor (15) and the scrap preheating housing (12) are additionally formed so as to be longitudinally displaceable by arranging the conveyor (15) and the scrap preheating housing (12) on roller members (25).

8. The scrap preheating device according to any one of claims 1 to 4, characterized in that the input area (17) of the scrap (5) is formed in the form of a gate so that the entry of ambient air into the cross section of the scrap preheating housing (12) can be restricted by at least one blocking member (36, 38).

9. The scrap preheating device according to any one of claims 1 to 4, characterized in that an air-permeable member (44) is arranged in the air intake region (42), the extraction device (48) acts on the air-permeable member (44), and the air-permeable member (44) is formed to move the scrap (5) in the form of a slide, wherein the air-permeable member (44) is a perforated plate.

10. The scrap preheating device according to any one of claims 1 to 4, characterized in that the input area (17) for the scrap (5) is arranged on the top side (31) of the scrap preheating housing (12) at an end area (30) opposite the transfer area (19).

11. The scrap preheating device according to any one of claims 1 to 4, characterized in that the transfer zone (19) is formed so as to be closable by means of a locking member (22).

12. The scrap preheating device according to any one of claims 1 to 4, characterized in that a further conveying device (90) for the scrap (5) is arranged in the transition region from the feed shaft (32) for the scrap (5) into the scrap preheating housing (12).

13. The scrap preheating device according to claim 12, characterized in that further conveying means (90) for the scrap (5) are arranged in the upper region of the two opposite side walls (80, 82) of the scrap preheating housing (12).

14. Method for scrap preheating for a furnace (50), using a scrap preheating device (10) according to any one of claims 1 to 13, wherein in an input area (17) scrap (5) is fed to a conveyor (15), which conveyor (15) conveys the scrap (5) at least in a substantially horizontal conveying direction (70), the scrap (5) entering the furnace (50) is heated between the input area (17) and a transfer area (19) by using hot exhaust gases extracted from the furnace (50),

characterized in that the exhaust gases are extracted on the side of the input region (17) facing away from the transfer region (19) via at least a part of the cross section of the scrap preheating housing (12) extending perpendicularly to the conveying direction (70) of the scrap (5) in the conveying device (15) and/or in that the exhaust gases are extracted in the region of two opposite side walls (80, 82) of the scrap preheating housing (12) surrounding the conveying device (15).

15. Method according to claim 14, characterized in that at least almost the entire cross section of the scrap preheating housing (12) above the conveyor (15) is filled with the scrap (5).

16. Method according to claim 14 or 15, characterized in that the scrap (5) is not compressed when the scrap (5) is transferred between the input area (17) and the transfer area (19), and/or that the scrap (5) is transferred back towards the input area (17) by means of the transfer device (15) near the completion of the feeding process into the furnace (50).

17. The method according to claim 14 or 15, characterized in that a further conveyor (90) conveys the scrap (5) back against the conveying direction (70) of the conveyor (15), which further conveyor (90) is arranged in the transition region from a feed shaft (32) for the scrap (5) to the scrap preheating housing (12).