EP4072750B1 - Method of casting melt by means of a melt container in which a melt reception area is formed - Google Patents

Description

The invention relates to a method for casting melt by means of a melt container in which a melt receiving space is formed.

The DE 10 2007 011 253 A1 discloses a casting device with a melt container for metallic materials. An injector is arranged on the underside of the melt container and has an opening for discharging the melt. Furthermore, a closing device is designed, which serves to close the opening.

Other such casting devices with an injector are from the EP 3 274 113 B1 and from the DE 10 2009 004 613 A1 known. In addition, a master's thesis "Classification and characterization of process-related casting defects in an innovative permanent mold casting process", which was submitted to the Montanuniversität Leoben in February 2014, discloses such a casting device with an injector and a casting process that can be carried out with it.

Other casting devices with a lance are from the JP H11 33696 A , the EP 1 428 599 A1 and the US 6,332,357 B1 known.

The WO 2019/204845 A1 discloses a low-pressure casting device.

The object of the present invention was to overcome the disadvantages of the prior art and to provide a method for casting melt. The scope of the present invention is defined by independent claim 1, and further embodiments of the invention are set out in dependent claims 2-11.

The method according to the invention has the advantage that the oxide skin that forms is not introduced into the casting mold. This can improve the quality of the cast workpiece. Furthermore, the method according to the invention has the advantage that the oxide skin does not get into the spout of the melt container, which means that contamination of the spout of the melt container can be prevented. In particular, this can ensure that the melt container remains functional over a longer period of time, since contamination of the spout would reduce the functionality of the melt container for future castings. In addition, the measures according to the invention can prevent freezing of oxide skin residues or melt residues in the sink. Especially with aluminum or aluminum alloys, an oxide skin forms very quickly on the surface.

Furthermore, it can be expedient if, in order to fill the melt receiving space of the melt container, the lance is immersed in a melting crucible filled with melt in such a way that the pouring opening of the lance is below the crucible filling level during the entire filling process. This has the advantage that by immersing the lance into the melting crucible filled with melt, the melt can be introduced into the melt receiving space of the melt container via the lance, which also functions as a spout.

In a first embodiment variant, the lance can be immersed so deeply in the melting crucible that the melt penetrates from the melting crucible into the melt receiving space of the melt container due to gravity due to the effect of the vessels communicating with one another.

In an alternative embodiment variant, a negative pressure can be applied in the melt receiving space of the melt container, whereby the melt is drawn from the melting crucible into the melt receiving space.

Furthermore, it can be provided that immediately before the lance is immersed in the melting crucible, at least part of the remaining melt located in the melt receiving space of the melt container is drained into the melting crucible. This has the advantage that the drained melt breaks through or displaces the oxide skin in the melting crucible, so that when the lance is immersed in the melting crucible, the oxide skin is pushed away from the lance and the oxide skin can therefore be prevented from adhering to the lance. On the one hand, this has the surprising advantage that the quality of the melt received in the melt receiving space can be improved. In addition, this measure can prevent the oxide skin in the crucible from clogging the lance. These measures also have the advantage that the oxide skin in the crucible does not adhere to the outside of the lance, which can improve the longevity of the lance.

In addition, it can be provided that the melt receiving space of the melt container has a non-wettable surface, in particular a ceramic surface, to which the oxide skin of the melt does not adhere. This has the advantage that the oxide skin located in the melt receiving space of the melt container can move up or down depending on the fill level of the melt container during the filling process or during the emptying process, without mixing with the melt.

Also advantageous is an embodiment according to which it can be provided that when filling the melt container with melt between 1% and 30%, in particular between 5% and 20%, preferably between 10% and 15% more melt is taken into the melt receiving space, than is required for casting the cast workpiece. Filling in this value range in particular results in a surprisingly good efficiency of the casting process. In addition, when filling in this value range, freezing of the melt can be avoided particularly efficiently and good quality of the melt can be achieved.

According to a further development, it is possible for the melt receiving space of the melt container to be completely emptied at periodic intervals and/or before the melt container is shut down, and for the oxide skin to be blown out of the melt receiving space by means of a gas blast. This has the advantage that even when the Melt container no oxide skin remains in the melt receiving space or that the melt receiving space can be thoroughly cleaned at periodic intervals.

Furthermore, it can be useful if the oxide skin located on the surface of the melt in the melt receiving space is vacuumed off at periodic intervals and/or before the melt container is shut down. This has the advantage that no oxide film remains in the melt receiving space even when the melt container is shut down or that the melt receiving space can be thoroughly cleaned at periodic intervals.

In addition, it can be provided that the oxide skin located on the surface of the melt in the melt receiving space is drained off at periodic intervals and/or before the melt container is shut down via an oxide skin drain opening formed in the melt container. This has the advantage that no oxide film remains in the melt receiving space even when the melt container is shut down or that the melt receiving space can be thoroughly cleaned at periodic intervals.

Furthermore, it can be provided that the melt receiving space is designed in such a way that it is sealed in a gas-tight manner when it is at least partially filled with melt, with a gas valve being formed, by means of which gas can be introduced into or discharged from the melt receiving space, with the melt container being filled melt, the gas valve is open so that the melt can flow from the melting crucible into the melt receiving space via the lance, and after the melt inflow process, the gas valve is closed and then, with the gas valve closed, as much melt is drained from the melt receiving space back into the melting crucible via the lance, until a negative pressure is established which is sufficiently large to keep the remaining melt in the melt receiving space. This has the advantage that the melt container does not have to be designed to be able to generate negative pressure in the melt receiving space, but that only one valve is sufficient for introducing gas into the melt receiving space or for releasing gas from the melt receiving space. In a first embodiment variant, it can be provided that the melt is pressed into the melt receiving space by means of a pressure line, such as the line of a low-pressure furnace, which is coupled to the lance.

In a further embodiment variant, it can be provided that the melt container is immersed so deeply in a crucible filled with melt that the melt flows into the melting crucible through the communicating vessels via the lance due to gravity. Furthermore, it can be provided that when casting the at least one cast workpiece, the melt from the melt container is admitted into the casting mold in a first process step at a first inflow speed until the pouring opening is at least partially immersed in the melt introduced into the casting mold and that in a second process step the melt is let into the mold at a second inflow speed, the second inflow speed being greater than the first inflow speed. This has the advantage that the turbulence when the melt is admitted into the mold can be kept as low as possible.

According to the invention it is provided that when filling the melt container with melt in a first process step the lance is moved, in particular pivoted, on the surface of the melting crucible in such a way that the oxide skin located on the surface is torn open and in a second process step the lance is moved in the torn area the oxide skin is immersed in the melt in the crucible. This has the advantage that this measure can keep the oxide skin away from the lance, so that contamination of the lance by the oxide skin can be largely prevented.

In particular, it can be provided that the oxide skin is torn open using the immersion aid.

A lance in the sense of this document is seen as a spout with a narrowed cross-section in relation to the melt container. In particular, it can be provided that the lance is at least partially tubular.

Furthermore, it can be provided that when filling the melt container with melt, so much more melt is taken up into the melt receiving space that when the melt container is filled again with melt, the level of the melt surface of the melt remaining in the melt receiving space is above the lance, in particular within the melt receiving space . This has the advantage that the oxide skin on the melt surface is in an area with an approximately constant cross-section remains and is therefore not excessively deformed. This means that the oxide skin is not mixed with the melt.

For a better understanding of the invention, it will be explained in more detail using the following figures.

Fig. 1

eine schematische Schnittdarstellung eines ersten Ausführungsbeispiels einer Schmelzetransportvorrichtung mit einem Siphon;

Fig. 2

einzelne Verfahrensschritte eines erstmaligen Füllvorganges zum Füllen eines Schmelzeaufnahmeraumes mit Schmelze;

Fig. 3

einzelne Verfahrensschritte eines erneuten Füllvorganges zum Füllen eines Schmelzeaufnahmeraumes mit Schmelze;

Fig. 4

einzelne Verfahrensschritte eines alternativen Füllvorganges zum Füllen eines Schmelzeaufnahmeraumes mit Schmelze;

Fig. 5

eine schematische Darstellung eines weiteren alternativen Füllvorganges zum Füllen eines Schmelzeaufnahmeraumes mit Schmelze unter Verwendung eines Niederdruckofens;

Fig. 6

eine erste Ausführungsvariante einer Ausgussöffnung;

Fig. 7

eine zweite Ausführungsvariante einer Ausgussöffnung;

Fig. 8

eine dritte Ausführungsvariante einer Ausgussöffnung;

Fig. 9

eine vierte Ausführungsvariante einer Ausgussöffnung;

Fig. 10

ein erstes Ausführungsbeispiel einer Gießvorrichtung;

Fig. 11

ein zweites Ausführungsbeispiel einer Gießvorrichtung;

Fig. 12

ein Ausführungsbeispiel eines Schnellverschlusses zum Ankoppeln einer Lanze an einen Schmelzebehälter.

They show in a highly simplified, schematic representation:

Fig. 1

a schematic sectional view of a first exemplary embodiment of a melt transport device with a siphon;

Fig. 2

individual process steps of an initial filling process for filling a melt receiving space with melt;

Fig. 3

individual process steps of a new filling process for filling a melt receiving space with melt;

Fig. 4

individual process steps of an alternative filling process for filling a melt receiving space with melt;

Fig. 5

a schematic representation of a further alternative filling process for filling a melt receiving space with melt using a low-pressure furnace;

Fig. 6

a first embodiment variant of a pouring opening;

Fig. 7

a second embodiment variant of a pouring opening;

Fig. 8

a third embodiment variant of a pouring opening;

Fig. 9

a fourth embodiment variant of a pouring opening;

Fig. 10

a first embodiment of a casting device;

Fig. 11

a second embodiment of a casting device;

Fig. 12

an embodiment of a quick-release fastener for coupling a lance to a melt container.

As an introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numbers or the same component names, whereby the disclosures contained in the entire description can be transferred analogously to the same parts with the same reference numbers or the same component names. The position information selected in the description, such as top, bottom, side, etc., is also related to the figure directly described and shown and, in the event of a change in position, these position information must be transferred accordingly to the new position.

Fig. 1 shows a first exemplary embodiment of a melt transport device 1, which is used to transport melt 2.

The melt transport device 1 has a melt container 3, in which a melt receiving space 4 is formed, which serves to hold the melt 2. The melt receiving space 4 has a surface 38 on its inside, which is in contact with the melt 2 when the melt receiving space 4 is filled.

Furthermore, the melt transport device 1 includes a spout 5, which is coupled to the melt container 3. The spout 5 can be designed as an integral part of the melt container 3. Furthermore, it is also conceivable that the spout 5 is designed as a separate component, which is coupled to the melt container 3. The spout 5 has a pouring opening 6 through which the melt 2 received in the melt container 3 can flow out of the melt transport device 1 into a casting mold.

The pouring opening 6 can have a circular cross section. Furthermore, it is also conceivable that the pouring opening 6 has a square cross section. In addition, it is also conceivable that the pouring opening 6 has a rectangular cross section, in particular a longitudinal extent of the pouring opening 6, which runs normal to the cutting plane, can have a large extent. For example, the longitudinal extent of the pouring opening 6 can be up to 2000mm, in particular up to 500mm. This is particularly advantageous for elongated cast workpieces, such as cylinder blocks or cylinder heads.

Of course, this elongated extension of the pouring opening 6 can also be advantageous in the other embodiment variants.

Furthermore, a gas valve 7 is formed, which is fluidly connected to the melt receiving space 4 and which is designed to regulate the gas entry into the otherwise gas-tight melt receiving space 4. The gas valve 7 is arranged above a filling level maximum 8, so that no melt 2 can flow into the gas valve 7. The filling level maximum is selected so that when the melt container 3 is filled with melt 2 up to the filling level maximum 8, a gas-filled space remains in the melt receiving space 4, in which a pressure can be adjusted using the gas valve 7.

Furthermore, a pressure detection means 9 can be provided, by means of which an internal pressure in the melt receiving space 4 can be detected. The gas pressure in the melt receiving space 4 can thus be adjusted specifically using the gas valve 7.

As in the exemplary embodiment Fig. 1 Furthermore, it can be seen that it can be provided that the melt transport device 1 has a fill level sensor 10, which serves to detect an actual fill quantity level 11. The actual filling quantity level 11 can thus be continuously recorded and compared with a target filling quantity level 12.

Furthermore, a weighing cell 39 can be designed, by means of which the weight and thus the fill level of the melt receiving space 4 can be recorded.

How out Fig. 1 Furthermore, it can be seen that the melt transport device 1 has a siphon 13 which has a reservoir 14 which is arranged between the melt receiving space 4 and the pouring opening 6. Furthermore, a siphon wall 15 is formed, which projects into the reservoir 14 in such a way that when the reservoir 14 is filled with melt up to an overflow level 17, the melt receiving space 4 is closed gas-tight with respect to the outside of the melt container 16. Here, the siphon 13 is designed in the spout 5 so that the reservoir 14 has the overflow level 17, with the siphon wall 15 being designed such that it has a lower edge 32 of the siphon wall. The siphon wall 15 projects into the reservoir 14 in such a way that a lower edge 32 of the siphon wall is arranged at a lower level than the overflow level 17.

In Fig. 1 the melt container 3 is shown partially filled with melt 2. How out Fig. 1 As can be seen, the structure described results in a first melt surface 18, which is arranged on the outside of the melt container 16 or is assigned to it. Further a second melt surface 19 is formed, which is arranged in the melt receiving space 4 of the melt container 3. The second melt surface 19 corresponds to the filling level 11. The ambient pressure of the melt container 3 acts on the first melt surface 18. The internal pressure of the melt receiving space 4 acts on the second melt surface 19.

For the transport of the melt container 3, it can be advantageous if, as in Fig. 1 shown, the first melt surface 18 is slightly below the overflow level 17. This means that spilling of the melt 2 can be avoided as best as possible. This level difference can be achieved, for example, by reducing the pressure in the melt receiving space 4. Alternatively, the melt container 3 can be shaken or slightly tilted immediately after filling in order to achieve this level difference immediately after the melt container 3 has been filled. Of course, it is also possible for the melt container 3 to be manipulated while the level of the first melt surface 18 is the same as the overflow level 17.

How out Fig. 1 Furthermore, it can be seen that the spout 5 is designed in the form of a lance 20 and that the siphon 13 is arranged on the underside of the lance 20. In the illustrations of the exemplary embodiments, the diameter of the lance 20 is shown to be excessively large to improve clarity. In particular, it can be provided that the lance 20 is designed to be slimmer than shown and therefore has a greater length compared to its diameter.

Furthermore, it can of course also be provided that the siphon 13 is integrated directly into the lance 20. A siphon 13 integrated into the lance 20 can work according to the same operating principle as described here.

In the exemplary embodiment according to Fig. 1 The siphon 13 can comprise an upwardly open container 21, which is coupled to the spout 5 by means of struts 22. In this exemplary embodiment, an upper edge of the container 21 simultaneously defines the overflow level 17. In the present exemplary embodiment Fig. 1 If gas is admitted into the melt receiving space 4 by means of the gas valve 7, the second melt surface 19 lowers, as a result of which the melt 2 located in the melt receiving space 4 runs through a pouring channel 23 into the reservoir 14, whereby the first melt surface 18 is raised. The first The melt surface 18 rises until the melt 2 runs out over the overflow level 17.

Furthermore, it can also be provided that the container 21, which is open at the top, is arranged on the spout 5 in a changeable manner.

How out Fig. 1 Furthermore, it can be seen that it can be provided that an immersion aid 47 is arranged on the underside of the lance 20a, 20b. The dipping aid 47 serves to tear open the oxide skin located on the surface of the melting crucible 25 when the lance 20a, 20b is dipped into the melting crucible 25, so that the lance 20a, 20b can be dipped under the layer of the oxide skin to fill the melt container and further When filling the melt container 3, the oxide skin should, if possible, not get into the melt receiving space 4. In particular, it can be provided that the immersion aid 47 has a pointed shape, so that tearing open the oxide skin is made easier.

Furthermore, it can be provided that the underside of the lance 20a, 20b or the immersion aid 47 is designed in such a way that they do not have any protruding surfaces, so that when the lance 20a, 20b is pulled out of the crucible 25, there is as little oxide skin as possible on the lance 20a, 20b adheres. In particular, it can be provided that all upwardly directed surfaces of the lance 20a, 20b are designed to be conical or to point obliquely downwards, so that the oxide skin is rejected when the lance 20a, 20b is pulled out.

In the Figures 2a to 2c a further and possibly independent embodiment of the melt transport device 1 is shown, again with the same reference numbers or component names for the same parts as in the previous one Figure 1 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous section Figure 1 pointed out or referred to.

In the Figures 2a to 2c A possible filling process for filling the melt receiving space 4 with melt 2 is shown schematically.

How out Fig. 2a As can be seen, it can be provided that the melt 2 is provided in a melting crucible 25 of a melting furnace 24 and that the melt container 3 is positioned above the melting crucible 25.

How out Fig. 2b As can be seen, the melt container 3 can be at least partially immersed in the melt 2 arranged in the melting crucible 25 in a further process step, so that the pouring opening 6 is immersed in the melting crucible 25 below the crucible filling level 27 of the melt 2. If the gas valve 7 is now opened or is already open during immersion, the melt 2 can flow into the melt receiving space 4 of the melt container 3 via the pouring opening 6. This position of the melt container 3 can also be referred to as the filling position 26.

If the gas flowing out of the melt receiving space 4 can pass through the gas valve 7 without pressure, the actual filling level 11 will adapt to the furnace filling level 27 when the melt container 3 is filled. When the gas valve 7 is subsequently closed and the melt container 3 is raised, the actual filling level 11 will decrease until the negative pressure in the melt receiving space 4 is sufficiently large to keep the melt 2 at the same level due to the pressure difference between the interior pressure in the melt receiving space 4 and the ambient pressure.

When the target filling level 12 in the melt receiving space 4 is reached, the gas valve 7 can be closed and the melt container 3, as in Fig. 2c visible, can be raised again.

When the melt container 3 is lifted, as much melt 2 flows from the melt receiving space 4 back into the melting crucible 25 until a pressure that is reduced compared to the environment is established in the melt receiving space 4, which holds the melt in the melt receiving space 4.

In a further development, it can be provided that further melt 2 is then drained from the melt receiving space 4 by opening the gas valve 7 until a desired fill level of melt 2 in the melt receiving space 4 is reached. The desired fill level of melt 2 can be selected in this way

This desired level of melt 2 in the melt receiving space 4 is selected so that after casting the cast workpiece or workpieces, a remainder of melt 2 remains in the melt receiving space 4.

In a subsequent process step, the melt container 3 can be transported to its casting position.

In the Figures 3a to 3c a further and possibly independent embodiment of the melt transport device 1 is shown, with the same reference numbers or component names as in the previous ones for the same parts Figures 1 and 2 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous sections Figures 1 and 2 pointed out or referred to.

In the Figures 3a to 3c A possible filling process for renewed or repeated filling of the melt receiving space 4 with melt 2 is shown schematically.

How out Fig. 3a As can be seen, it can be provided that immediately before the melt container 3 is refilled, a remainder of melt 2, which has an oxide skin formed on the melt surface 19, is located in the melt receiving space 4 of the melt container 3. In other words, the melt 2 was not completely poured out during the previous casting process. Of course, several cast workpieces can also have been cast, although not all of the melt 2 located in the melt receiving space 4 of the melt container 3 was consumed when the last cast workpiece was cast.

In the Fig. 3a This situation is not explicitly shown, but it is possible that before the melt container 3 is immersed in the melting crucible 25, at least part of the melt 2 still in the melt receiving space 4 of the melt container 3 is drained off, so that this melt jet penetrates the oxide skin of the melt 2 Crucible 25 breaks open and displaced.

In the Figures 4a and 4b a further and possibly independent embodiment of the melt transport device 1 is shown, with the same reference numbers or component names as in the previous ones for the same parts Figures 1 to 2 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous sections Figures 1 to 2 pointed out or referred to.

In the 4a and 4b an alternative method for filling the melt receiving space 4 with melt 2 is shown.

Like from the 4a and 4b As can be seen, it can be provided that the melt container 3 only dips so far into the melting crucible 25 that the pouring opening 6 is below the crucible filling level 27.

In order to now reach the target filling quantity level 12 in the melt receiving space 4, the melt receiving space 4 can be evacuated by means of a vacuum pump 28, whereby the melt 2 is drawn into the melt receiving space 4. The gas valve 7 can then be closed in order to keep the actual filling level 11 in the melt receiving space 4 at a constant level during the transport of the melt transport device 1.

Since the melt receiving space 4 before lifting the melt container 3, as in Fig. 4b is shown, has already been evacuated by the vacuum pump 28, the actual filling level 11 in the melt receiving space 4 will only decrease slightly when it is raised.

In the Figure 5 a further and possibly independent embodiment of the melt transport device 1 is shown, with the same reference numbers or component names as in the previous ones for the same parts Figures 1 to 4 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous sections Figures 1 to 4 pointed out or referred to.

How out Fig. 5 As can be seen, it can be provided that the melt transport device 1 is filled by means of a low-pressure furnace 33 known to those skilled in the art. Here, a riser pipe 34, which projects into the melting crucible 25 of the low-pressure furnace 33, can be coupled directly to the pouring opening 6 in order to establish a flow connection between the riser pipe 34 and the melt receiving space 4. If the gas valve 7 is opened during the filling process, the function of the low-pressure furnace 33 can be used to push the melt 2 upwards in the riser pipe 34 until the melt receiving space 4 is filled with melt 2 up to its target filling level 12.

In such an embodiment variant it can also be provided that the riser pipe 34 of the low-pressure furnace 33 and the spout 5 are coupled to one another by means of a coupling 31.

In the In the Figures 6 to 9 A further and possibly independent embodiment of the siphon 13 is shown in each case, with the same reference numbers or component names as in the previous ones for the same parts Figures 1 to 5 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous sections Figures 1 to 5 pointed out or referred to.

Like from the Fig. 6 to 9 As can be seen, it can be provided that the siphon 13 is tubular. In the Fig. 6 to 9 Various design options for the pouring opening 6 are shown.

In the exemplary embodiment according to Fig. 6 the pouring opening 6 is round. Such a shape of the pouring opening 6 results when the pipe which forms the siphon 13 is cut off normal to the pipe center axis.

In the exemplary embodiment according to Fig. 7 It is provided that a drip nose 35 is formed on the pouring opening 6. The drip nose 35 serves to keep the oxide adhesion to the pouring opening 6 as low as possible when casting a cast workpiece. In the exemplary embodiment according to Fig. 7 is the pouring opening 6 also, as in the exemplary embodiment Fig. 6 , arranged at right angles to the pipe center axis. The pipe is in the exemplary embodiment Fig. 6 and Fig. 7 in the area of the pouring opening 6 when the lance 20 is in a vertical position, it is slightly inclined downwards, with a pipe end angle 36 being formed at an angle smaller than 90°.

In the exemplary embodiment according to Fig. 8 the pipe is cut obliquely in the area of the pouring opening 6, so that the pouring opening 6 is oval.

How out Fig. 9 As can be seen, it can be provided that the pouring opening 6 is fan-shaped and thus has a greater extent in its width than the extent in its height. A pouring opening 6 designed in this way is particularly suitable for casting wide cast workpieces.

In the Fig. 10 A further and possibly independent embodiment of the casting device 37 is shown, with the same reference numbers or component names as in the previous ones for the same parts Figures 1 to 9 be used. Around To avoid unnecessary repetitions, refer to the detailed description in the preceding Figures 1 to 9 pointed out or referred to.

Fig. 10 shows a first embodiment of a casting device 37 for casting cast workpieces. How out Fig. 10 As can be seen, it can be provided that the melt transport device 1 has a first melt container 3a and a second melt container 3b. The first melt container 3a has a first melt receiving space 4a and a first spout 5a in the form of a lance 20a located at the bottom of the first melt container 3a. The spout 5a has a pouring opening 6a.

How out Fig. 10 Furthermore, it can be seen that it can be provided that the second melt container 3b can be designed to be identical to the first melt container 3a.

The second melt container 3b has a second melt receiving space 4b and a second spout 5b in the form of a lance 20b located at the bottom of the second melt container 3b. The spout 5b has a pouring opening 6b.

The melt transport device 1 can be designed such that both melt containers 3a, 3b can be moved simultaneously and synchronously with one another. In particular, it can be provided that both melt containers 3a, 3b are moved together by means of common drive devices. As a result, the structure of the melt transport device 1 can be kept as simple as possible.

The casting device 37 also includes a casting mold 29, which has a mold cavity 30. In particular, a first mold 29a is assigned to the first melt container 3a and a second mold 29b is assigned to the second melt container 3b. By means of the in Fig. 10 In the casting device 37 shown, two casting workpieces can be cast using just one melt transport device 1. The structure or control of the melt transport device 1 can be kept as simple as possible.

How out Fig. 10 Furthermore, it can be seen that a pivoting device 40 is designed, which has a pivot bearing 41, by means of which the melt containers 3a, 3b can be pivoted about a horizontal axis of rotation 42. How out Fig. 10 As can be seen, it can be provided that each of the melt containers 3a, 3b has its own pivot drive 43 has. The two melt containers 3a, 3b can thus be pivoted individually and independently of one another.

Furthermore, it can be provided that the mold 29 can also be pivoted about a horizontal axis. The mold 29 and the melt container 3 can thus be pivoted at the same time.

How out Fig. 10 Furthermore, it can be seen that it can be provided that a distance adjustment device 44 is formed, by means of which a distance 45 of the lance 20a of the first melt container 3a and the lance 20b of the second melt container 3b can be adjusted to one another.

The distance adjustment device 44 can be as follows Fig. 10 can be seen, for example in the form of a linear adjustment device.

In a further embodiment, it is also conceivable that the distance adjustment device 44 is designed, for example, in the form of a fastening arm for receiving the melt container 3a, 3b, with a change in the distance 45 being achieved by pivoting the fastening arm and thus the melt container 3a, 3b about a vertical axis can be.

In the Fig. 11 A further and possibly independent embodiment of the casting device 37 is shown, with the same reference numbers or component names as in the previous ones for the same parts Figures 1 to 10 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous sections Figures 1 to 10 pointed out or referred to. In particular, the in Fig. 11 Casting device 37 shown has a similar structure to that in Fig. 10 illustrated casting device 37.

How out Fig. 11 As can be seen, it can be provided that both melt containers 3a, 3b are arranged on a common receptacle, the pivot bearing 41 being designed such that both melt containers 3a, 3b can be pivoted at the same time about the horizontal axis of rotation 42 by means of the one pivot drive 43.

In the Fig. 12 A further and possibly independent embodiment of the casting device 37 is shown, with the same reference numbers or

Component names as in the previous ones Figures 1 to 11 be used. In order to avoid unnecessary repetitions, please refer to the detailed description in the previous sections Figures 1 to 11 pointed out or referred to.

How out Fig. 12 As can be seen, it can be provided that the lance 20 is coupled to the melt container 3 by means of a quick-release fastener 46, in particular by means of a bayonet fastener. In the present exemplary embodiment according to Fig. 12 A shaped element is formed in the melt container 3, with a recess corresponding to the shaped element being formed on the lance 20. If the lance 20 is placed on the melt container 3 and rotated through a certain angle, the lance 20 can be locked on the melt container 3 using the quick-release fastener 46.

The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants with one another are possible and this variation possibility is based on the teaching on technical action through the subject invention Skills of the specialist working in this technical field.

The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the different exemplary embodiments shown and described can represent independent inventive solutions in their own right. The task underlying the independent inventive solutions can be found in the description.

All information on value ranges in this description should be understood to include any and all sub-ranges, e.g. the information 1 to 10 should be understood to include all sub-ranges, starting from the lower limit 1 and the upper limit 10 , that is, all subranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, for example 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

For the sake of order, it should finally be pointed out that in order to better understand the structure, elements have sometimes been shown out of scale and/or enlarged and/or reduced in size. <b>Reference symbol list</b> 1 Melt transport device 31 coupling 2 melt 32 Lower edge of siphon wall 3 melt container 33 Low pressure furnace 4 Melt receiving room 34 Riser pipe 5 spout 35 Drip nose 6 Spout opening 36 Pipe end angle 7 Gas valve 37 Casting device 8th Fill level maximum 38 Surface of the melt receiving space 9 Pressure sensing means 10 Level sensor 39 load cell 11 Actual filling level 40 Swivel device 12 Target filling level 41 Pivot bearing 13 siphon 42 horizontal axis of rotation 14 reservoir 43 Swivel drive 15 Siphon wall 44 Distance adjustment device 16 Melt container outside 45 Distance 17 Overflow level 46 Quick release 18 first melt surface 47 Immersion aid 19 second melt surface 20 lance 21 container 22 strut 23 Spout channel 24 smelting furnace 25 melting pot 26 Filling position 27 Crucible level 28 vacuum pump 29 mold 30 Mold cavity

Claims (11)

1. A method for casting a melt (2) by means of a melt container (3) in which a melt receiving space (4) is formed, wherein the melt container (3) has a spout (5) in the form of a lance (20) located on the bottom on the melt container (3), wherein the method comprises the following method steps:

   - filling the melt container (3) with melt (2), wherein the melt (2) is introduced into the melt receiving space (4) of the melt container (3) out of a crucible (25) by means of a spout orifice (6) of the lance (20);

   - casting at least one cast workpiece with melt (2) from the melt container (3), wherein the melt (2) received in the melt receiving space (4) is introduced into a mold (29) via the spout orifice (6) of the lance (20);

   - filling the melt container (2) with melt (3) again,

   characterized in that
   during the filling of the melt container (3) with melt (2), so much more melt (2) is received in the melt receiving space (4) than is required for casting the cast workpiece, that directly before the renewed filling of the melt container (3), a remainder of melt (2), which has an oxide skin formed at the melt surface (19), is present in the melt receiving space (4) of the melt container (3), wherein the level of the melt surface (19) of the melt remaining in the melt receiving space (4) lies above the lance (20) inside the melt receiving space (4).
2. The method according to claim 1, wherein for filling the melt receiving space (4) of the melt container (3), the lance (20) is immersed in a crucible (25) filled with melt (2) such that the spout orifice (6) of the lance (20) lies below the crucible fill level (27) during the entire filling operation.
3. The method according to claim 2, wherein directly before immersing the lance (20) in the crucible (25), at least a part of the melt (2) remaining in the melt receiving space (4) of the melt container (3) is discharged into the crucible (25).
4. The method according to one of the preceding claims, wherein the melt receiving space (4) of the melt container (3) has a non-wettable surface (38), in particular a ceramic surface (38), to which the oxide skin of the melt (2) does not adhere.
5. The method according to one of the preceding claims, wherein while filling the melt container (3) with melt (2), between 1% and 30%, in particular between 5% and 20%, preferably between 10% and 15%, more melt (2) is received in the melt receiving space (4) than is required for casting the cast workpiece.
6. The method according to one of claims 1 to 3 and 5, wherein the melt receiving space (4) of the melt container (3) is emptied completely in periodic intervals and/or before shutting down the melt container (3), and the oxide skin is blown out of the melt receiving space (4) by means of a gas blast.
7. The method according to one of claims 1 to 3 and 5 to 6, wherein the oxide skin present in the melt receiving space (4) at the surface of the melt (2) is sucked off in periodic intervals and/or before shutting the melt container (3) down.
8. The method according to one of claims 1 to 3 and 5 to 7, wherein the oxide skin present in the melt receiving space (4) at the surface of the melt (2) is removed, in particular discharged in periodic intervals and/or before shutting the melt container (3) down by means of an oxide skin discharge orifice formed in the melt container (3).
9. The method according to one of the preceding claims, wherein the melt receiving space (4) is configured such that when it is at least partially filled with melt (2), it is closed off in a gas-tight manner, wherein a gas valve (7) is formed, by means of which gas can be fed into or removed from the melt receiving space (4), wherein the gas valve (7) is opened while the melt container (3) is being filled with melt (2), so that the melt (2) can flow out of the crucible (25) and into the melt receiving space (4) via the lance (20), and the gas valve (7) is closed after the melt (2) has flown in, and subsequently, while the gas valve (7) is closed, melt (2) is discharged from the melt receiving space (4) back into the crucible (25) via the lance (20) until a vacuum is generated that is sufficient to keep the remaining melt (2) in the melt receiving space (4).
10. The method according to one of the preceding claims, wherein, when casting the at least one cast workpiece, the melt (2) is admitted, in a first method step, from the melt container (3a, 3b) into the mold (29a, 29b) at a first inflow speed until the spout orifice (6) is immersed at least partially in the melt (2) introduced into the mold (29a, 29b), and that in a second method step, the melt (2) is admitted into the mold (29a, 29b) at a second inflow speed, wherein the second inflow speed is greater than the first inflow speed.
11. The method according to one of the preceding claims, wherein, while filling the melt container (3a, 3b) with melt (2), in a first method step, the lance (20) is moved, in particular pivoted, at the surface of the crucible (25) such that the oxide skin at the surface is torn open, and in a second method step, the lance (20) is immersed in the melt present in the crucible (25) in the torn region of the oxide skin.

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