EP3163240B1 - Pan lifting device and method of vertically displacing a metal bath pan - Google Patents

Description

The invention relates to a ladle lifting device for a metallurgical plant.

It is known to subject metals in the liquid state of a metallurgical treatment in order to increase their quality. An example of a metallurgical treatment process is the so-called RH process (Ruhrstahl-Heraeus process), in which a molten metal, in particular liquid steel, is subjected to a vacuum treatment in order to decarburize and additionally degas the molten metal.

From the so-called ladle metallurgy it is known to pour a molten metal to be treated in a metal bath pan and to transport the metal bath pan on a transport device to a treatment device, for example, to a vacuum treatment vessel of a Ruhrstahl-Heraeus plant. Typically, the metal bath pan is positioned under the treatment device.

In order to bring the metal bath pan into a position in which the molten metal contained in the metal bath pan can be treated by means of the treatment device, the metal bath pan is usually raised so that in particular an inlet pipe of the treatment apparatus is immersed in the metal bath pan. After completion of the metallurgical treatment of the molten metal, the metal bath pan is then lowered again and transported away by means of the transport device. Subsequently, another metal bath pan, which contains a further molten metal to be treated, can be transported to the treatment device on the same or another transport device and the further molten metal can be subjected to a metallurgical treatment in an analogous manner.

To raise and lower a metal bath pan, a pan lift is needed.

A ladle lifting device is eg in WO 2012/000218 A1 disclosed. This pan lifting device comprises a lifting frame on which a metal bath pan can be mounted, and a plurality of lifting cylinders, by means of which the lifting frame can be raised together with the metal bath pan. The lifting frame and the metal bath pan have a high dead weight and therefore require powerful designed and therefore costly lifting cylinder.

An object of the invention is to provide a low-cost ladle lifting device for a metallurgical plant.

This object is achieved by a pan lifting device with the features of claim 1.

The ladle lifting device according to the invention has a lifting arm with a rotatably mounted arm member, a first drive element for driving the rotatably mounted arm member of the lifting arm and a first pan holding unit connected to the lifting arm for holding a metal bath pan.

An advantage of this ladle lifting device is that it can be realized with a low weight, in particular because the ladle lifting device does not require a massive lifting frame for lifting the metal bath pan. This allows the use of a less powerful and therefore less expensive drive element than in the prior art.

Furthermore, it is possible to dispense with a separate foundation for the ladle lifting device, so that no costly foundation work is required for the ladle lifting device. The pan lifting device, for example, on an existing scaffold of the metallurgical plant on which, for example, a treatment vessel is stored stored be and / or be mounted on such a scaffold.

Advantageous developments of the pan lifting device according to the invention are each the subject of dependent claims and the following description.

In the present case, a metal bath pan can be understood as meaning a metallurgical pan for holding a metal bath melt, also called a metal bath.

In an advantageous embodiment of the invention, the lift arm on an upper arm member and a connected to the upper arm member forearm member. Preferably, the upper arm member and the lower arm member are interconnected by a hinge, whereby in particular an angle between the upper arm member and the lower arm member is adjustable. The lifting arm is thus preferably a Gelenkhubarm. This allows a compact or space-saving design of Pfannenhubvorrichtung. In addition, this can provide good accessibility to other elements of the metallurgical plant, e.g. to a treatment vessel, in particular when the arm members are brought into a corresponding position.

Preferably, the upper arm member is rotatably mounted. That is, the upper arm member may be the aforementioned rotatably mounted arm member of the lift arm. Further, it is advantageous if the lower arm member is connected to the first cup holding unit, in particular by a hinge. Conveniently, the lower arm member is connected at one end (ie with one of its ends) to the first cup holding unit and the other end (ie with another of its ends) connected to the upper arm member.

According to a preferred embodiment of the invention, the first drive element is a lifting cylinder, in particular a hydraulic, pneumatic or Elektrohubzylinder. Because a lifting cylinder provides a cost effective means of driving the In addition, the lifting cylinder can be made compact, so that it allows good accessibility to other elements of the metallurgical plant. Means for controlling the lifting cylinder, such as a pressure fluid reservoir and / or a pressure medium pump can be placed away from the lifting cylinder.

The first drive element may include, among other things, a cylinder housing. Furthermore, the first drive element may have a push rod. The push rod may be adapted to exert a force or a torque on the rotatably mounted arm member of the lift arm.

Further, it is advantageous if the first drive element is aligned at least substantially vertically. In the present case, an element may be considered to be substantially vertically aligned if it is inclined by at most 10 °, preferably by at most 5 °, with respect to a vertical. In particular, the first drive element can be arranged such that its push rod can be extended downwards out of its cylinder housing.

Furthermore, the ladle lifting device expediently has a shaft, in particular a horizontally mounted shaft. Advantageously, the rotatably mounted arm member of the lifting arm is connected to the shaft. In particular, it is advantageous if the rotatably mounted arm member of the lifting arm is rotationally fixedly connected to the shaft. By a rotationally fixed connection can be achieved that a rotational or pivoting movement of the shaft causes the rotatably mounted arm member performs a rotary or pivoting movement at the same angular velocity.

Preferably, the upper arm member of the lift arm is connected at one end to the shaft, in particular connected rotationally fixed, and the other end connected to the lower arm member of the lifting arm.

The shaft may for example have a crank pin. About the crank pin, the shaft can be driven by means of the drive element. Alternatively or additionally, the rotatably mounted arm member may have an arm extension. Furthermore, the first drive element may be connected to the crank pin or to the arm extension, in particular by a hinge.

In an advantageous development of the invention, the ladle lifting device has a second drive element. Conveniently, the second drive element is arranged for driving the rotatably mounted arm member of the lift arm. Furthermore, the second drive element can be arranged parallel to the first drive element. The second drive element may e.g. be provided for redundancy reasons. If the first or the second drive element has a defect, the metal bath pan can be raised, lowered and / or held using the respective other drive element.

The two drive elements can be arranged side by side. Alternatively, the two drive elements may be spaced from each other. For example, a distance between the two drive elements amount to at least 80% of the length of the shaft. In particular, the two drive elements can be placed at or above different ends of the shaft.

The second drive element may be identical or substantially identical to the first drive element. Further, any or all of the aforementioned features relating to the first drive member may also refer to the second drive member.

Conveniently, the first cup holding unit comprises a retaining hook for hooking to a retaining pin of the metal bath pan.

Moreover, it is advantageous if the first cup holding unit comprises a Hubtraverse, in particular a horizontally oriented Hubtraverse. At this Hubtraverse example, the aforementioned holding hooks can be attached. Preferably, the retaining hook is centered - with respect to the longitudinal extent of Hubtraverse - attached to the Hubtraverse. Further, it is advantageous if the Hubtraverse is connected at one of its two ends to the lifting arm, in particular to the lower arm of the lifting arm, for example by a hinge. Alternatively, the lifting arm, in particular the lower arm member of the lifting arm, be connected without a Hubtraverse with the retaining hook.

In a preferred manner, the pan lifting device is equipped with a further lifting arm. Furthermore, it is preferred if the ladle lifting device has a second pan holding unit. The further lifting arm is expediently connected to the second cup holding unit, in particular by a hinge.

The second cup holding unit may be identical or substantially identical to the first cup holding unit. Further, any or all of the aforementioned features related to the first cup holding unit may also refer to the second cup holding unit.

Furthermore, the further lift arm can be configured identically or substantially identically to the first-mentioned lift arm. Some or all of the aforementioned features relating to the former lift arm may also apply to the second lift arm.

Furthermore, it is expedient if the further lifting arm has a rotatably mounted arm member. The rotatably mounted arm member of the further lift arm is preferably drivable by the first drive element and / or by the second drive element.

Moreover, it is advantageous if the pan lifting device has two additional lifting arms. The additional lifting arms expediently each have a rotatably mounted arm member. Preferably, one of the two additional lifting arms is connected to the first cup holding unit, whereas the other of the two lifting arms is connected to another cup holding unit, in particular to the aforementioned second cup holding unit.

The load to be lifted by the ladle lifting device can be divided between the individual lifting arms of the ladle lifting device, in particular divided into equal parts.

Moreover, it is advantageous if the pan lifting device has one or more additional drive elements, preferably two additional drive elements. Conveniently, the two additional lifting arms are driven by the additional drive element or the additional drive elements.

The additional lift arms may be identical or substantially identical to the first-mentioned lift arm. Some or all of the aforementioned features relating to the former lift arm may also apply to the additional lift arms.

Furthermore, the additional drive elements may be configured identically or substantially identically to the first drive element. Some or all of the aforementioned features relating to the first drive member may also apply to the additional drive members.

Furthermore, the invention is directed to a metallurgical plant with the ladle lifting device according to the invention, in particular with an advantageous development of the ladle lifting device according to the invention as described above. The metallurgical plant can, for example, a RH plant (Ruhrstahl-Heraeus plant) to perform the RH process.

Conveniently, the metallurgical plant comprises a scaffold for supporting or supporting a metallurgical treatment vessel. The scaffold may include, inter alia, a plurality of vertically oriented longitudinal beams and a plurality of horizontally oriented transverse beams.

Preferably, the pan lifting device is mounted on the scaffold. In this way, it is possible to dispense with a separate foundation for the ladle lifting device and, consequently, cost-intensive foundation work. Preferably, the Pfannenhubvorrichtung is attached to the scaffold. In particular, the drive elements of the pan lifting device can each be connected by a rotary joint with a crossbar of the metallurgical plant.

The metallurgical plant may further comprise a metallurgical treatment vessel, in particular a vacuum treatment vessel. In addition, the system may include a vessel change car. The treatment vessel can be mounted on the vessel change car, wherein the vessel change car can in turn be mounted on the support structure.

Furthermore, the metallurgical plant may comprise a metal bath pan that can be lifted and lowered by the pan lifter.

Furthermore, the invention relates to a method for vertically displacing a metal bath pan.

In the method according to the invention, it is provided that a rotatably mounted arm member of a lifting arm of a pan lifting device is driven by means of a drive element of the pan lifting device, so that the rotatably mounted arm member performs a pivoting movement, and the metal bath pan by the pivoting movement of the rotatably mounted Arm member is displaced vertically by means of a lifting arm connected to the pan holding unit.

The method provides a cost effective way of vertically displacing a metal bath pan.

The elements mentioned in connection with the method can in particular be elements of the previously described ladle lifting device or of the metallurgical system described above.

Vertical displacement of an element, in particular the metal bath pan, can be understood to mean raising or lowering this element. Conveniently, in vertical displacement, the direction of movement of the element is parallel to a vertical, i. vertically aligned.

Further, it is expedient if the metal bath pan is held by the cup holding unit, in particular on a retaining pin of the metal bath pan.

Preferably, a push rod of the drive element is extended down to raise the metal bath pan. Further, it is preferred if a connected with the rotatably mounted arm member further arm member of the lifting arm is guided upwards. The further arm member of the lifting arm is expediently a lower arm member of the lifting arm.

To lower the metal bath pan, the push rod of the drive element is preferably retracted upwards. Further, it is preferred if in this case the further arm member of the lifting arm is guided downwards.

Conveniently, when lifting the metal bath pan, an angle between the two arm members is reduced. When lowering the metal bath pan, the angle between the two arm members expediently increases.

The previously given description of advantageous embodiments of the invention contains numerous features, which are given in the individual subclaims partially summarized in several. However, these features may conveniently be considered individually and combined into meaningful further combinations. In particular, these features can be combined individually and in any suitable combination with the device according to the invention and the method according to the invention. Thus, process features, objectively formulated, can also be seen as a property of the corresponding device unit and vice versa.

Although some terms are used in the specification or claims in the singular or in conjunction with a number word, the scope of the invention for these terms should not be limited to the singular or the respective number word. Further, the words "a" and "an" are not to be understood as number words but as indefinite articles.

The above-described characteristics, features, and advantages of the invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following description of the embodiments of the invention, which will be described in connection with the drawings. The embodiments serve to illustrate the invention and do not limit the invention to the combinations of features specified therein, not even with respect to functional features. In addition, suitable features of each embodiment may also be explicitly considered isolated, removed from one embodiment, incorporated into another embodiment to supplement it, and combined with any of the claims.

FIG 1

eine Vorderansicht einer RH-Anlage mit einem Stützgerüst, einem Vakuumbehandlungsgefäß, einem Gefäßwechselwagen, einer Metallbadpfanne, einem Pfannenwagen und einer Pfannenhubvorrichtung;

FIG 2

eine Seitenansicht der RH-Anlage aus FIG 1;

FIG 3

eine isometrische Darstellung der RH-Anlage, wobei die auf dem Pfannenwagen angeordnete Metallbadpfanne seitlich versetzt zum Vakuumbehandlungsgefäß platziert ist;

FIG 4

eine isometrische Darstellung der RH-Anlage, wobei die auf dem Pfannenwagen angeordnete Metallbadpfanne unter dem Vakuumbehandlungsgefäß platziert ist;

FIG 5

eine isometrische Darstellung der RH-Anlage in einem angehobenen Zustand der Metallbadpfanne;

FIG 6

eine isometrische Darstellung der RH-Anlage, wobei das auf dem Gefäßwechselwagen angeordnete Vakuumbehandlungsgefäß seitlich versetzt zum Stützgerüst angeordnet ist;

FIG 7

eine perspektivische Darstellung einer alternativen RH-Anlage mit einem Stützgerüst, einem Vakuumbehandlungsgefäß, einem Gefäßwechselwagen und einer Pfannenhubvorrichtung; und

FIG 8

eine perspektivische Darstellung der Pfannenhubvorrichtung der alternativen RH-Anlage aus FIG 7.

Show it:

FIG. 1

a front view of an RH plant with a scaffold, a vacuum treatment vessel, a vessel change car, a metal bath pan, a ladle carriage and a pan lifter;

FIG. 2

a side view of the RH plant FIG. 1 ;

FIG. 3

an isometric view of the RH plant, wherein the arranged on the ladle car metal bath pan is placed laterally offset from the vacuum treatment vessel;

FIG. 4

an isometric view of the RH plant, wherein the arranged on the ladle metal bath pan is placed under the vacuum treatment vessel;

FIG. 5

an isometric view of the RH system in a raised state of the metal bath pan;

FIG. 6

an isometric view of the RH plant, wherein the arranged on the vessel change car vacuum treatment vessel is arranged laterally offset from the scaffold;

FIG. 7

a perspective view of an alternative RH plant with a scaffold, a vacuum treatment vessel, a vessel change car and a Pfannenhubvorrichtung; and

FIG. 8

a perspective view of Pfannenhubvorrichtung the alternative RH system FIG. 7 ,

FIG. 1 shows a front view of a metallurgical plant 2. The metallurgical plant 2 in the present embodiment is an RH plant (Ruhrstahl-Heraeus plant) for decarburizing a molten metal, in particular for decarburizing liquid steel.

The metallurgical plant 2 comprises inter alia a support structure 4 with a plurality of vertically oriented longitudinal beams 6 and a plurality of horizontally oriented transverse beams 8, which are connected to the longitudinal beams 6.

In addition, the metallurgical plant 2 comprises a vessel change car 10, which is mounted on the support frame 4, in particular on two transverse bars 8 of the support frame 4. Furthermore, the metallurgical plant 2 comprises a vacuum treatment vessel 12, which in turn is mounted on the vessel change carriage 10. During operation of the metallurgical plant 2, the vacuum treatment vessel 12 is connected at its upper end with an intake manifold, not shown figuratively, which in turn is connected to a vacuum pump, not shown figuratively, by means of which a vacuum in the vacuum treatment vessel 12 can be generated. Furthermore, the vacuum treatment vessel 12 has a dip tube unit 14.

Furthermore, the metallurgical plant 2 comprises a metal bath pan 16 and a ladle carriage 18 for transporting the metal bath pan 16 FIG. 1 the metal bath pan 16 mounted on the ladle cart 18 is placed under the vacuum treatment vessel 12. Furthermore, the metal bath pan 16 has two retaining pins 20, of which in FIG. 1 only one is recognizable (cf. FIG. 2 ).

Furthermore, the metallurgical plant 2 has a ladle lifting device 22, which is mounted on the support frame 4 and by means of which the metal bath pan 16 can be raised and lowered again.

The Pfannenhubvorrichtung 22 includes four drive elements 24, which are each configured in the present embodiment as a lifting cylinder. The drive elements 24 can in particular hydraulic, pneumatic or Elektrohubzylinder be. Compressed air, hydraulic or electrical control lines, via which the drive elements 24 are controllable, are not shown figuratively for the sake of clarity.

In FIG. 1 only two of the four drive elements 24 can be seen, since these two drive elements 24 conceal the other two drive elements 24 (cf. FIG. 6 ). Two of the four drive elements 24 are arranged parallel to one another on a first side 26 of the support frame 4. The other two drive elements 24 are arranged on one of the first side 26 opposite the second side 28 of the support frame 4 parallel to each other and mirror-symmetrical to the first two drive elements 24.

Each of the drive elements comprises a cylinder housing 30 and a push rod 32. Further, the drive elements 24 are substantially vertically aligned and arranged such that their push rods 32 are extendable downward from their cylinder housings 30.

In addition, the pan lifting device 22 comprises four lifting arms 34 each having a rotatably mounted upper arm member 36 and a respective lower arm member 38. In FIG. 1 only two of the four lift arms 34 can be seen, since these two lift arms 34 obscure the other two lift arms 34 (see. FIG. 2 ). Two of the four lift arms 34 are arranged on the first side 26 of the support frame 4. The other two lifting arms 34 are arranged on the second side 28 of the scaffold 4 mirror-symmetrical to the two first-mentioned lifting arms 34.

The upper arm member 36 of the respective lift arm 34 is connected by a pivot 40 to the lower arm member 38 of the respective lift arm 34, so that an angle between the two arm members 36, 38 is adjustable.

Furthermore, the ladle lifting device 22 comprises two pan holding units 42 each having a lifting crossbar 44 and a attached to the Hubtraverse 44 retaining hook 46th In FIG. 1 is only one of the cup holding units 42 recognizable (see. FIG. 2 ). In addition, the retaining hooks 46 in the in FIG. 1 shown state hooked to the retaining pin 20 of the metal bath pan 16.

In addition, the pan lifting device 22 comprises two horizontally aligned shafts 48, which are each mounted on a lower transverse bar of the support frame 4 (see. FIG. 2 ). Both shafts 48 each have two crank pin 50 in the middle. One of the two shafts 48 is arranged on the first side 26 of the support frame 4, while the other of the two shafts 48 is arranged on the second side 28 of the support frame 4.

The two arranged on the first side 26 of the support frame 4 lift arms 34 are connected with their respective upper arm member 36 rotationally fixed to that shaft 48 which is disposed on the first side 26 of the support frame 4. Accordingly, the two arranged on the second side 28 of the support frame 4 lift arms 34 are connected with their respective upper arm member 36 rotationally fixed to that shaft 48 which is disposed on the second side 28 of the support frame 4. Here, the upper arm members 36 are each attached to one end of the corresponding shaft 48.

Furthermore, each of the drive elements 24 at one end (and at its upper end) are each connected by a pivot 52 with an upper crossbar 8 of the support frame 4. At the other end (ie at its lower end), each of the drive elements 24 is connected to one of the crankpins 50 by a pivot 54 so that the drive elements 24 respectively drive the lift arms 34 connected to the shaft 48 via the shaft 48 disposed on the same side of the support frame 4 can. Furthermore, the drive elements 24 are each arranged on the outside of the support frame 4, so that good accessibility to the vacuum treatment vessel 12 is given, which in turn allows a quick and / or low-cost replacement of the vacuum treatment vessel 12.

Furthermore, the two lifting cross members 44 are each connected at one of its two ends to the lower arm members 38 of the lifting arms 34 arranged on the first side 26 of the supporting frame 4. Further, the two Hubtraversen 44 are each connected to the other of its two ends with the lower arm members 38 of arranged on the second side 28 of the support frame 4 lifting arms 34. The Hubtraversen 44 are each connected by a rotary joint 56 with the respective lower arm member 38.

FIG. 2 shows a side view of the metallurgical plant 2, wherein the metallurgical plant 2 is shown in the same state as in FIG. 1 ,

In FIG. 2 are (in addition to some of the elements described above) one of the two previously mentioned shafts 48, both cup holding units 42 of Pfannenhubvorrichtung 22, and both retaining pin 20 of the metal bath pan 16 recognizable. Also, in FIG. 2 two of the four drive elements 24 are shown, which are arranged side by side on the same side of the scaffold 4.

The use of the ladle lifting device 22 to lift the metal bath pan 16 is explained below with reference to FIGS. 3 to 5.

FIG. 3 shows an isometric view of the metallurgical plant 2 in a state in which the pan car 18 and arranged on the pan car 18 metal bath pan 16 are arranged laterally offset from the support frame 4. In this state, the push rods 32 of the drive elements 24 are retracted as far as possible in the cylinder housing 30 of the respective drive member 24, wherein the Hubtraversen 44 are each in their lowest position.

If a metallurgical treatment of a molten metal bath located in the metal bath pan 16 is to take place, the metal bath pan 16 is first moved under the vacuum treatment vessel 12 with the aid of the ladle carriage 18. Subsequently, the retaining hooks 46 are hooked to the retaining pin 20 of the metal bath pan 16 (see. FIG. 4 ).

FIG. 4 shows an isometric view of the metallurgical plant 2 in a state in which the pan car 18 and disposed on the pan car 18 metal bath pan 16 are located under the vacuum treatment vessel 12 and the two retaining hooks 46 are hooked to the retaining pin 20 of the metal bath pan 16. Here, the push rods 32 of the drive elements 24 are a bit far out of the cylinder housing 30 of the respective drive element 24 extended and the two Hubtraversen 44 are in a slightly higher position than in FIG. 3 ,

From this state, the metal bath pan 16 is lifted by the ladle lifting device 22 until the dip tube unit 14 of the vacuum treatment vessel 12 dips into the molten metal contained in the metal bath pan 16, so that a metallurgical treatment of the molten metal can be performed by the vacuum treatment vessel 12 (see FIG. FIG. 5 ).

The lifting arms 34 of the pan lifting device 22 are driven by means of the drive elements 24. To lift the metal bath pan 16, the push rods 32 of all four drive elements 24 are extended synchronously and with the same amplitude from downwards out of the respective cylinder housing 30. In this case, each of the drive elements 24 exerts a torque on the respective shaft 48 via the crank pin 50 connected to it, which is thereby set into rotary motion. This, in turn, causes the upper arm members 36 of the lifting arms 34, which are connected in a rotationally fixed manner to the shafts 48, to execute a rotary / pivoting movement. By the pivotal movement of the upper arm members 36, the lower arm members become 38 and connected to the lower arm members 38 Hubtraversen 44 led upwards. In this way, the metal bath pan 16 is raised by means of the retaining hooks 46 fastened to the lifting crosspieces 44.

FIG. 5 11 shows an isometric view of the metallurgical plant 2 in a state in which the metal bath pan 16 is lifted so far that the dip tube unit 14 of the vacuum treatment vessel 12 dips into the molten metal present in the metal bath pan 16.

To lower the metal bath pan 16 again, the push rods 32 of all four drive elements 24 are moved synchronously and with the same amplitude upwards into the respective cylinder housing 30. As a result, the upper arm links 36 of the lift arms 34, which are connected in a rotationally fixed manner to the shafts 48, now execute a pivoting movement in the opposite direction. By this rotational / pivotal movement of the upper arm members 36, the lower arm members 38 and connected to the lower arm members 38 Hubtraversen 44 are guided downward. In this way, the metal bath pan 16 is lowered by means of the retaining bars 46 fastened to the lifting crosspieces 44.

The metal bath pan 16 is e.g. then lowered when the metallurgical treatment of the molten metal is completed and / or when an exchange of the vacuum treatment vessel 12 is intended.

If an exchange of the vacuum treatment vessel 12 is intended, for example, because a lining of the vacuum treatment vessel 12 to be replaced, the Hubtraversen 44 Pfannenhubvorrichtung 22 are each brought to their lowest position, so that the vacuum treatment vessel 12 can be moved away from the scaffold 4 using the vessel changing car 10 (see. FIG. 6 ).

FIG. 6 shows an isometric view of the metallurgical plant 2 in a state in which the Gefäßwechselwagen 10 and mounted on the vessel changing car 10 vacuum treatment vessel 12 are placed laterally offset to the support frame 4 and the Hubtrversen 44 of Pfannenhubvorrichtung 22 are each in their lowest position.

It is also in FIG. 6 the metal bath pan 16 is arranged on the ladle carriage 18, which is placed laterally offset relative to the support frame 4.

The description of the following embodiment is limited primarily to the differences from the preceding, in connection with 1 to 6 discussed embodiment, to which reference is made with respect to the same features and functions. Essentially identical or mutually corresponding elements are, as far as appropriate, designated by the same reference numerals and features not mentioned are taken over in the following embodiment, without being described again.

FIG. 7 shows a perspective view of an alternative metallurgical plant 58. Also in the metallurgical plant 58 of the present embodiment is an RH plant for decarburizing a molten metal, in particular for decarburizing liquid steel.

This metallurgical plant 58 also includes a ladle cart and a metal bath pan. However, these are in FIG. 7 for better clarity not shown.

In contrast to the metallurgical plant 2 from the preceding exemplary embodiment, in the case of the metallurgical plant 58 of the present exemplary embodiment, the upper arm members 36 of the lifting arms 34 each have an arm extension 60 on. For missing in the Pfannenhubvorrichtung 22 of the present metallurgical plant 58, the crank pin 50th

Furthermore, each of the drive elements 24 is connected at its lower end in each case via a pivot 62 with one of the arm extensions 60. In the present embodiment, when raising or lowering the metal bath pan, each of the drive elements 24 directly exerts a torque on the upper arm link 36 connected to it.

Furthermore, the drive elements 24 arranged on the same side of the metallurgical system 58 are spaced apart from one another, their distance from one another being approximately 90% of the length of the respective shaft 48.

FIG. 8 shows in isolation the ladle lifting device 22 of the metallurgical plant 58 from FIG. 7 in a perspective view. In FIG. 8 the arm extension 60 of the respective upper arm member 36 is better recognizable.

Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

2

investment

4

scaffold

6

stringers

8th

crossbeam

10

Vascular change car

12

Vacuum treatment vessel

14

The drop tube assembly

16

Metallbadpfanne

18

ladle cars

20

retaining pins

22

Pfannenhubvorrichtung

24

driving element

26

page

28

page

30

cylinder housing

32

pushrod

34

lifting arm

36

upper arm link

38

arm link

40

swivel

42

Cup holding unit

44

lifting beam

46

retaining hook

48

wave

50

crank pin

52

swivel

54

swivel

56

swivel

58

investment

60

arm extension

62

swivel

Claims (15)

1. Ladle lifting device (22) for a metallurgical plant (2, 58), having a lifting arm (34) with a rotatably mounted arm element (36), a first driving element (24) for driving the rotatably mounted arm element (36) of the lifting arm (34) and a first ladle holding unit (42), connected to the lifting arm (34), for holding a molten metal ladle (16).
2. Ladle lifting device (22) according to Claim 1,
   characterized in that the lifting arm (34) has an upper arm element (36) and a lower arm element (38) connected to the upper arm element (36) by a rotary joint (40), the upper arm element (36) being rotatably mounted and the lower arm element (38) being connected to the first ladle holding unit (42) by a rotary joint (56).
3. Ladle lifting device (22) according to Claim 1 or 2,
   characterized in that the first driving element (24) is a lifting cylinder, e.g. a hydraulic, pneumatic or electrical lifting cylinder, and has a cylinder housing (30) and a pushrod (32), the first driving element (24) being aligned substantially vertically, being aligned substantially vertically inclined with respect to a vertical by at most 10°, preferably by at most 5°, and arranged in such a way that its pushrod (32) can be extended downward out of its cylinder housing (30).
4. Ladle lifting device (22) according to one of the preceding claims,
   characterized by a horizontally mounted shaft (48), to which the rotatably mounted arm element (36) of the lifting arm (34) is connected for conjoint rotation.
5. Ladle lifting device (22) according to Claim 4,
   characterized in that the shaft (48) has a crankpin (50), to which the first driving element (24) is connected by a rotary joint (54), or in that the rotatably mounted arm element (36) has an arm extension (60), to which the first driving element (24) is connected by a rotary joint (62).
6. Ladle lifting device (22) according to one of the preceding claims,
   characterized by a second driving element (24) for the rotatably mounted arm element (36) of the lifting arm (34), the second drive element (24) being arranged parallel to the first driving element (24).
7. Ladle lifting device (22) according to Claim 7,
   characterized in that the first ladle holding unit (42) comprises a holding hook (46) for hooking onto a holding pin (20) of the molten metal ladle (16).
8. Ladle lifting device (22) according to Claim 7,
   characterized in that the first ladle holding unit (42) comprises a lifting crossmember (44), on which the holding hook (46) is secured and which is connected at one of its two ends to the lifting arm (34) by a rotary joint (56).
9. Ladle lifting device (22) according to one of the preceding claims,
   characterized by a second ladle holding unit (42) and a further lifting arm (34), which is connected to the second ladle holding unit (42) by a rotary joint (56) and has a rotatably mounted arm element (36), which can be driven by the first driving element (24).
10. Ladle lifting device (22) according to one of the preceding claims,
    characterized by two additional driving elements (24) and two additional lifting arms (34), which have in each case a rotatably mounted arm element (36), which can be driven by the two additional driving elements (24), one of the two additional lifting arms (34) being connected to the first ladle holding unit (42) and the other of the two lifting arms (34) being connected to another ladle holding unit (42).
11. Metallurgical plant (2, 58) with a ladle lifting device (22) according to one of the preceding claims and a supporting framework (4) for carrying a metallurgical treatment vessel (12), the ladle lifting device (22) being mounted on the supporting framework (4).
12. Metallurgical plant (2, 58) according to Claim 11,
    characterized by a metallurgical treatment vessel (12), e.g. a vacuum treatment vessel, and a vessel changing carriage (10), in which the treatment vessel (12) is mounted, the vessel changing carriage (10) for its part being mounted on the supporting framework (4).
13. Method for vertically moving a molten metal ladle (16), in which a rotatably mounted arm element of a lifting arm (34) of a ladle lifting device (22) is driven with the aid of a driving element (24) of the ladle lifting device (22), so that the rotatably mounted arm element (36) performs a pivoting movement, and the molten metal ladle (16) is moved vertically by the pivoting movement of the rotatably mounted arm element (36) by means of a ladle lifting unit (42) connected to the lifting arm (34).
14. Method according to Claim 13,
    characterized in that, for raising the molten metal ladle (16), a pushrod (32) of the driving element (24) is extended downward and in this case a further arm element (38) of the lifting arm (34) that is connected to the rotatably mounted arm element (36) is guided upward.
15. The method according to Claim 13 or 14,
    characterized in that, for lowering the molten metal ladle (16), a pushrod (32) of the driving element (24) is retracted upward and in this case a further arm element (38) of the lifting arm (34) that is connected to the rotatably mounted arm element (36) is guided downward.

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