Patent Application
20170314860
The present invention relates to a melting device according to the preamble of claim 1 and to a melting method according to the preamble of claim 16.
A melting device which is disclosed in DE 34 21 485 and has been developed by the inventor of the present invention, includes a furnace vessel and a charging material feed device, wherein the charging material feed device comprises a charging material shaft which is realized as a charging material pre-heating device, and wherein the charging material pre-heating device is set up to pre-heat charging material in the charging material feed shaft by means of furnace gas. The charging material is melted in melting cycles. Each melting cycle includes the feeding with several charges up to the tapping (casting of the melt). The individual charges pass through the charging material feed shaft into the furnace vessel. Whilst the first charge is being melted, for example, in the furnace vessel, the second charge is first of all poured into the charging material feed shaft and is pre-heated there. A disadvantage of said melting device is that it is not possible to pre-heat the first charge, which is associated with a following melting cycle, by means of furnace gas before the tapping for the preceding melting cycle is effected, as the first charge of the following melting cycle would get in the way of the tapping. This results in an inefficient use of energy.
In order to eliminate said disadvantage, blocking elements are used in a more recent melting device which is disclosed in DE 39 40 558 and has also been developed by the inventor of the present invention. On account of the blocking elements, the first charge, which is associated with a following melting cycle, can already be poured into the charging material feed shaft and pre-heated by means of furnace gas before the tapping is effected for the preceding melting cycle, the blocking elements preventing the first charge of the following melting cycle sliding into the furnace vessel during the tapping and obstructing the tapping. Water cooling is used, as a rule, for the blocking elements. A disadvantage of said melting device is that a large amount of energy is required for said water cooling. The blocking elements are additionally exposed to thermal stress and can be damaged by thudding charging material. EP 0 971 193 also discloses blocking elements which alleviate the difficulties connected thereto. However, said blocking elements also require a large amount of energy for the water cooling.
DE 20 2010 016 851 discloses a melting device which comprises a charging material feed shaft which is not realized as a charging material pre-heating device, but comprises a charging material bunker which is realized as a charging material pre-heating device. Said melting device does not require any blocking elements. No pre-heating takes place in the charging material feed shaft. The furnace gas which is used to pre-heat the charging material in the charging material bunker, has hardly cooled when it reaches the charging material bunker, which is why the charging material bunker is realized with water cooling. Said cooling requires a large amount of energy.
In addition, the furnace gas still has a high temperature when it leaves the charging material bunker. In order to use said thermal energy of the furnace gas to also pre-heat the charging material, an additional charging material pre-heating device is necessary which requires additional structural expenditure.
WO 2012/062254 discloses a melting device having a furnace vessel and a charging material feed device, the charging material feed device comprising a charging material shaft and charging material bunker, the charging material shaft being realized as a charging material pre-heating device, the charging material pre-heating device being set up to pre-heat charging material in the charging material feed shaft by means of furnace gas. The melting device is additionally realized in such a manner that hardly any furnace gas passes in an uncontrolled manner into the environment. In addition, the melting device does not require blocking elements. The charging material shaft is realized and arranged in such a manner that charging material passes through the charging material shaft into the furnace vessel not just due to gravity. A slider is provided in order to move the charging material out of the charging material shaft into the furnace vessel. The charging material bunker is separated from die charging material shaft by a horizontally drivable partition wall. Said partition wall is driven together with a horizontally drivable slider which conveys the charging material from the charging material bunker into the charging material shaft. In this case, the partition wall itself moves into the charging material shaft and cannot be moved back until the charging material column has dropped sufficiently in the charging material shaft, whereupon a further charge is only then able to be poured into the charging material bunker and then forwarded into the charging material shaft in order to be pre-heated there. The time required until the partition wall is moved back, is consequently not available for the pre-heating of the further charge. In practice, it has also been shown that the partition wall is quickly damaged such that furnace gas is able to escape in an uncontrolled manner through the damaged partition wall when the charging material bunker is being loaded.
A inciting device having a pivoting device in order to pivot a furnace vessel into different pivot positions is disclosed in DE 39 06 653. The furnace vessel comprises a furnace vessel opening. The feed shaft comprises a shaft opening. During the melting operation of the melting device, charging material slides from the feed shaft through the shaft opening and through the furnace vessel opening into the furnace vessel. When the slag or the melt is to be poured out, the furnace vessel has to be pivoted by means of the pivoting device. To this end, however, it is first of all necessary to lift up the feed shaft and move it to the side. This results in an opening, through which furnace gas is able to escape or air is able to be drawn in, which results in a loss of thermal energy.
The object underlying the present invention is to create a melting device and a melting method which are particularly energy-efficient.
The object underlying the invention is achieved by a melting device with the features of the characteristic part of claim 1 and by a melting method with the features of the characteristic part of claim 16.
The present invention relates to a melting device having a tilting device in order to tilt the furnace vessel into different tilt positions, wherein the furnace vessel comprises a furnace vessel sealing region. with a sealing surface which surrounds a furnace vessel opening, wherein the feed shaft, which is associated with the furnace vessel, comprises a shaft sealing region with a complementary sealing surface which surrounds the shaft opening of the feed shaft, and wherein the sealing surface is situated opposite the complementary sealing surface for different tilt Positions of the tilt device. The loss of thermal energy is reduced as a result of the unwanted outflow of furnace gas being prevented at least extensively by means of extensively abutting sealing surfaces. The loss of thermal energy is also reduced as a result of the unwanted drawing-in of air and the resultant heating of said air being prevented. As a result, the energy efficiency of the melting device is increased. In addition, the air quality in the room in which the melting device is situated is improved.
In a preferred embodiment, the sealing surface of the furnace vessel sealing region is a convex, cylinder-surface-portion-shaped surface and the complementary sealing surface of the shaft sealing region comprises a complementary concave, cylinder-surface-portion-shaped contour. A cylinder-surface-portion-shaped surface, in conjunction with the present invention, is a surface which lies on a (fictitious) cylinder surface. The axes of the cylinders on which the cylinder-surface-portion-shaped surface or contour lies preferably coincide with a rotational axis about which the tilting device is tilted, at least one pivot joint preferably being located on the rotational axis. The complementary sealing surface of the feed shaft preferably comprises, on two opposite sides, two sealing elements which project beyond the sealing surface of the furnace vessel sealing region in a tilt position.
In another preferred embodiment, which is also usable independently of the preceding realization of the invention, a charging material bunker, which is situated upstream of the feed device, comprises a feed opening with a feed opening closure element and a loading opening with a loading opening closure element. The charging material shaft is preferably connected to the charging material bunker by means of the feed opening. The charging material is preferably loaded into the charging material bunker through the loading opening. During the filling of the charging material bunker when the loading opening is open, the feed opening closure element prevents furnace gas flowing out of the feed shaft into the charging material bunker and then further through the loading opening. Once the charging material bunker has been filled when the feed opening is open, the feed opening closure element prevents furnace gas flowing out of the charging material bunker through the loading opening. The loading opening closure element and the feed opening closure element also prevent air being drawn-in from the outside. The loss of thermal energy is reduced as a result of preventing the unwanted outflow of furnace gas. The loss of thermal energy is also reduced as a result of preventing air being drawn-in in an unwanted manner and the resultant heating of said air. As a result, the energy efficiency of the melting device is further increased. In addition, the air quality in the room in which the melting device is situated is improved.
The feed opening closure element is preferably displaceable, movable or drivable into a region outside the charging material shaft for opening the feed opening. Charging material which is situated in the charging material shaft does not then obstruct the closing of the feed opening by the feed opening closure element such that the feed opening can be closed in good time, and a further charge can consequently be poured into the charging material bunker in good time in order to be pre-heated there. A guide means is preferably provided, along which the feed opening closure element is displaceable, movable or drivable. The feed opening closure element is preferably drivable in a vertical manner. The movement direction of the feed opening closure element therefore preferably has a vertical component, the vertical component preferably being greater than a horizontal component of the movement direction. A drive device is preferably provided in order to drive the feed opening closure element along the guide means. The loading opening closure element is preferably drivable in a horizontal manner. The movement direction of the loading opening closure element therefore preferably has a horizontal component, the horizontal component preferably being greater than a vertical component of the movement direction. A drive device is preferably provided in order to drive the loading opening closure element along a guide means.
The charging material bunker opens above the feed opening into the feed shaft which, in an advantageous realization, is provided with a gas outlet. Furnace gas can be drawn off by means of said gas outlet opening for instance by means of a gas channel. To this end, the feed opening of the feed shaft must be closed by means of a closure element. The furnace gas which flows through the feed shaft to the gas outlet heats, in a manner as intended, the charging material which is received in the feed shaft in the sense of pre-heating.
In yet another preferred embodiment, the charging material bunker comprises a further gas outlet opening. Furnace gas is drawn out of the charging material bunker through the gas outlet opening in particular when the loading opening is closed by the loading opening closure element and the feed opening is open such that the furnace gas is able to flow through the feed shaft into the charging material bunker. A gas channel preferably opens out into the further gas outlet opening. A gas suction device draws the furnace gas off through the gas channel. Said gas suction device can be identical to the aforenamed gas suction device. The further gas outlet opening is preferably arranged on an end of the charging material bunker which is remote from the feed opening of the feed shaft.
In a further development of the last-named preferred embodiment, a gas channel opens out in the gas outlet opening; the gas channel comprises a channel portion which runs beneath a floor of a bunker container of the charging material bunker to a pipe joint which is located in a rotational axis of the bunker container. This ensures that the extraction of the furnace gas through the channel portion does not impair the pivotability of the bunker container. A further channel portion preferably opens out in the pipe joint in order to forward furnace gas. The channel portions are preferably realized as pipes. In conjunction with the present invention, a pipe joint is a device which produces an articulated fluid connection between at least two pipes or the like. In an advantageous manner, said further development manages with a minimum of pipe joints and pipe portions.
In yet another preferred embodiment which is also usable independently of the previous designs of the invention, a furnace gas inhibiting device is provided with a blower. The blower is preferably provided in a passage between two regions and interrupts or obstructs at least the flowing of furnace gas from one of the regions to another of the regions by the blower blowing in a gas, preferably air, along a cross sectional surface of the passage. As a result, the air quality in the room in which the melting device is situated can be improved. The furnace gas inhibiting device makes it possible to dispense with a mechanical closure element in a region in which, in particular, damage can occur as a result of the charging material. In this case, the furnace gas inhibiting device is mounted so as to be pivotable preferably at the top of a passage, the furnace gas inhibiting device preferably being able to be pivoted up and down. The furnace gas inhibiting device preferably includes a partition wall. Said partition wall can block an upper part of a passage such that the flowing of furnace gas only has to be inhibited. in a lower part of the passage by blowing in gas or air where charging material, as a rule, is exclusively to be found. As an alternative to this, a driving device can also be provided in order to drive the furnace gas inhibiting device up and down.
In a further development of the last-named preferred embodiment, the furnace gas inhibiting device is provided in the charging material feed shaft. The furnace gas inhibiting device inhibits a flow of furnace gas from the charging material feed shaft to a bunker container, from where it could escape. The furnace gas inhibiting device is preferably provided downstream of a gas outlet opening in the charging material feed shaft such that furnace gas can be drawn in through the gas outlet opening in the charging material feed shaft.
In yet another preferred embodiment, which is also usable independently of the previous realizations of the invention, a pivoting device is provided for an additional charging material container in order to pivot the additional charging material container from a loading position to an unloading position and vice versa, and the pivoting device comprises two support arms in order to hold the additional charging material container on two opposite sides. A closable unloading opening is preferably situated on the floor of the additional charging material container. The pivoting device can be used, above all, on account of space restrictions.
The present invention additionally relates a melting device having a furnace vessel and a charging material feed device, wherein the charging material feed device comprises a charging material shaft and a charging material bunker, wherein the charging material shaft is realized as a charging material pre-heating device, wherein the charging material pre-heating device is set up to pre-heat charging material in the charging material feed shaft by means of furnace gas, wherein the charging material bunker is realized as a further charging material pre-heating device, and wherein the further charging material pre-heating device is set up to pre-heat charging material in the charging material bunker by means of furnace gas. In conjunction with the present invention, the charging material pre-heating device is then set up to pre-heat the charging material in the feed shaft by means of furnace gas (gas from a melting vessel interior) when the charging material feed shaft includes a space, through which the furnace gas flows out of the furnace vessel on account of a pressure difference which is produced, for example, by a suction device which draws off the furnace gas, wherein the space additionally contains a charge of charging material during a normal melting operation for a substantial time of at least one minute, preferably five minutes, even more preferred at least ten minutes. The charging material can move in the space whilst it is contained therein. The space can be suitable, for example, on account of particular dimensioning, to contain charging material for a considerable time during a normal melting operation. For example, the form, realization or dimensioning of the melting vessel and/or feed shaft can result in a charging material column forming in the feed shaft. In an analogous manner, in conjunction with the present invention, the further charging material pre-heating device is set up then to pre-heat charging material in the charging material bunker by means of furnace gas (gas from a melting vessel interior) when the charging material bunker includes a further space, through which the furnace gas flows out of the furnace vessel on account of a pressure difference which is produced, for example, by a suction device which draws off the furnace gas, wherein the further space contains a charge of charging material for a substantial time of at least one minute, preferably five minutes, even more preferred at least ten minutes during a normal melting operation. The charging material shaft is preferably realized and/or provided in such a manner that charging material passes from the charging material shaft into the furnace vessel due to gravity such that no further device is necessary to convey the charging material from the charging material shaft into the furnace vessel. This can be achieved, in particular, by means of realizing an upwardly pointing wall inside surface of the charging material shaft in an inclined manner and the position of the passage from the charging material shaft to the furnace vessel at the top of the furnace vessel.
The achievement of combining the feed shaft, which is realized as a charging material pre-heating device, with the charging material bunker, which is realized as a charging material pre-heating device, is that furnace gas, which flows from the feed shaft to the charging material bunker, has already cooled considerably. Consequently, the charging material bunker does not have to comprise any or hardly any cooling devices which, in turn, use energy. When the furnace gas has flowed out of the charging material bunker, it is additionally already greatly cooled such that no further pre-heating device is necessary in order to draw the thermal energy out of the furnace gas and avoid wasting energy as a result. The combination therefore achieves a synergetic effect. Approximately five percent of the energy required for the melting method is saved by dispensing with water-cooled. blocking elements.
According to valid claim 10, the realization of which is also independently usable, the bunker can be arranged on a platform so as to be drivable in such a manner that it is moved by means of a carriage up to a tilting device, by means of which the emptying of the bunker container of the bunker into the feed shaft of the melting device is made possible. The advantage of this is that the bunker containers with the charging material which can be inserted into the bunker only have to be lifted by such an amount above the height of the platform until said bunker containers are able to be inserted or emptied into the bunker. In other words, this means that the bunker containers do not have to be lifted, for instance, to a height above the feed opening of the feed shaft which means that the melting device, as a rule, is able to be supplied using the existing cranes. No new or additional cranes, which would make it possible to lift the bunkers to a height above the feed opening of the feed shaft, have to be purchased. In addition, correspondingly, for instance the height of existing buildings does not need to be increased for receiving the melting device according to the invention such that the melting device according to the invention can be set up in an existing building.
According to an advantageous further development said solution, the platform is realized such that, in addition to the bunker which has already been moved up to the feed opening of the feed shaft for the purposes of emptying, a further bunker can be arranged on the platform on the same rail arrangement such that the first bunker, once it has been emptied, can be removed to the side and then the further bunker can be driven on the platform up to the feed opening of the feed shaft by means of the carriage for the purposes or emptying. This means that, in the case of said realization, there is no longer a requirement to lift up a subsequently provided bunker container above the bunker that has just been emptied in order then to fill said bunker with the charging material of the subsequently provided bunker container through the loading opening thereof. In said case, the crane has therefore only to lift the subsequently provided bunker container above the platform, but not above the further bunker which is already situated on the platform. As a result, the melting device according to the invention can. be used in conjunction with a crane which is designed with a lower height or rather can also be used in a building which is lower in height.
In a, once again, advantageous further development of the invention, the platform can be provided additionally with its own lifting device for a further bunker container. In said case too, a further bunker container which is provided subsequently by means of the crane has then only to be lifted to a height that enables it to be set onto the rail arrangement of the platform, the subsequently provided bunker container then being raised by means of a lifting device which is associated with the platform and being moved up to the just emptied bunker in such a manner that the subsequently provided bunker container can then be emptied into the bunker container of the bunker which has just been emptied into the feed shaft. Said solution also ensures that the melting device is feedable using an existing crane and, apart from this, there is no need either for a higher building.
In a further advantageous design, the lifting device is additionally designed such that by means of said lifting device, a subsequently provided bunker container is pivotable by means of the lifting device. The advantage of this is that the subsequently provided bunker or bunker container can also be placed onto the platform transversely with respect to the bunker which has already been moved up to the feed shaft, that is to say not in the longitudinal direction, but in the transverse direction such that in the case of said design a shorter platform can be used and also the space required. for the melting device is accordingly reduced.
In an alternative design, the lifting device is not incorporated in the platform for parking the bunker or bunker container, but is arranged to the side next to said platform such that the subsequently provided bunkers or bunker containers are not deposited behind the bunker which has already been moved up to the feed shaft for the purposes of emptying, but rather next to the already postioned bunker, the space requirement also being reduced accordingly in the case of said realization.
The present invention additionally relates to a melting method which is carried out by a melting device having a furnace vessel and a charging material feed device, wherein the charging material feed device comprises a feed shaft and a charging material bunker with a bunker container, said method having the following steps:
In conjunction with the present invention, pre-heating the charging material by means of furnace gas means that the charging material is exposed to the furnace gas during a normal melting operation for a substantial time of at least one minute, preferably five minutes, even more preferred at least ten minutes. The pre-heating of the charging material in the feed shaft by means of furnace gas lasts therefore for a time at least one minute, preferably five minutes, even more preferred at least ten minutes. During the pre-heating of the charging material in the charging material bunker by means of furnace gas, the charging material can move in the charging material bunker. The pre-heating of the charging material in the feed shaft by means of furnace gas lasts therefore for a time of at least one minute, preferably five minutes, even more preferred at least ten minutes. During the pre-heating of the charging material in the feed shaft by means of furnace gas, the charging material can move in the feed shaft.
In a preferred embodiment, the melting method includes several charges of charging material, wherein for one of the several charges of charging material the following steps are carried out one after another:
The pre-heating in the feed shaft is not necessarily carried out for each charge. The pre-heating in the feed shaft, for example, can be omitted for a first charge in a melting cycle because the first charge slips through the feed shaft. The detail of the individual method steps can differ, in this case, for different charges. For example, the forwarding of a third charge can last much longer than the forwarding of a first charge, because charging material in the feed shaft obstructs the sliding of the third charge into the feed shaft. The pre-heating in the bunker container also then lasts longer. The feed opening is preferably opened and closed by means of displacing, moving or driving a feed opening closure element, the feed opening closure element being displaced, moved or driven into a region outside the charging material shaft during the opening of the feed opening. Charging material which is situated in the charging material shaft does not then obstruct the closing of the feed opening by the feed opening closing element such that the feed opening can be closed in good time and a further charge can be filled in the charging material bunker in good time in order to be pre-heated there.
In an alternative preferred embodiment, the melting method includes several charges of charging material, wherein for one of the several charges of charging material the following steps are carried out one after another:
In a further development of the two last-named preferred embodiments, the bunker container is tilted in order to forward the charge into the feed shaft. As an alternative to this, a slider can be provided in order to forward charging material out of the bunker container into the feed shaft.
The invention is described in more detail below with reference to the drawings, in which:
The furnace vessel 1 is mounted on a holder 3 with two holder components which are provided at opposite ends of the furnace vessel 1. One of said holder components is covered for the most part in
The feed device 2 comprises a bunker 12, a feed shaft 13 and a platform 14. The bunker 12 includes a bunker container 17, a carriage 29 and a tilting device 18. The bunker container 17 includes a front feed opening (not shown) which is closable by a plate-shaped closure element (not shown), and an upper loading opening 15 which is closable by a plate-shaped closure element 16. The plate-shaped closure elements are driven, for example, by a toothed rod mechanism which is controlled by the control means (not shown). The tilting device 18 includes a pivot joint (68, see
As an alternative to this, in the event of a larger gap in said region it is also possible to use an air barrier which shields the gap from the outside environment of the melting device. To this end, it is possible to arrange blowers, which shield the gap from the environment by means of an air curtain, for example above the gap on the outside of the feed shaft. The function of such an air curtain is explained at another point in connection with the furnace gas inhibiting device.
The sealing region of the furnace vessel is rotated relative to the sealing region of the feed shaft 13. The two sealing regions, however, nevertheless still abut against one another such that hardly any gap is realized between them and that hardly any furnace gas penetrates out of the melting device to the outside through said sealing regions.
A melting method, which runs in melting cycles, is explained below by way of
Steps i.) to vii.) normally run in the order given, it being unimportant whether step v.) is carried out after step vi.) or vii.).
The steps i.) to iii.) can be carried out for the first charge, which is associated with a following melting cycle, before the tap has been effected for the preceding melting cycle. In this case, it is possible for some steel scrap which is associated with the first charge to drop into the feed shaft 13. However, this does not provide a problem. The following melting cycle, in this case, directly follows the preceding melting cycle and even overlaps with it. The tapping and the discharging of the slag are effected prior to step iv.) for the first charge of the following melting cycle.
In the following description of further embodiments of the present invention, the same numbers as for the first embodiment are used as reference symbols for functionally identical elements followed by an additional letter.
For the following embodiments only the features which deviate substantially from the first embodiment are shown. Elements of the further embodiments which are not described are therefore realized by at least substantially identical elements. The features of various embodiments can be combined with one another insofar as this is technically possible.
The furnace gas is drawn off through a gas outlet opening 31c on the rear wall of the bunker 12c via a gas channel 20c. A grid 60c is provided in the gas outlet opening. A first channel portion 57c of the gas channel 20c runs first of all beneath the floor of a bunker container 17c and opens out in a pipe joint 58c. The pipe joint 58c lies in the rotational axis of the bunker container 12c when it is tilted. A second channel portion 59c, through which the furnace gas is drawn off, begins in the pipe joint 58c.
The closure element 16c includes a first closure plate 61c and a second closure plate 62c.
In a further improved realization according to
In a, once again, alternative design according to
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 115 671.4 | Oct 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2015/100454 | 10/28/2015 | WO | 00 |
