EP1862559B1 - Hoisting unit for steel processing pans in RH plants - Google Patents

Abstract

Lifting device (13) comprises lifting arms (14) on one end for interacting with holders (12) formed on a ladle (11). The arms are held in a fixed support (17) on the other end. The support comprises a runway (18) formed as a circular bent section on the support ends of the arms and a fixed revolving strip for axially guiding the runway during rotation of the arms.

Description

The invention relates to a hoist for lifting a ladle filled with liquid steel from a ladle transport vehicle to the dip tubes of the vacuum treatment vessel of an RH plant.

In a so-called RH plant, liquid steel is subjected to a vacuum treatment by immersing the vacuum treatment vessel with its dip tubes in the molten steel in the ladle. In order to keep the treatment times short, there is a requirement to make the diameter of the dip tubes according to the pan dimension as large as possible. In practice, for this purpose, in one embodiment, the vacuum treatment vessel is lowered into the ladle standing on a ladle transport vehicle. However, this has the disadvantage that the vacuum treatment vessel has numerous connections for the vacuum generation and the passage / suction of treatment gases, so that each movement of the vacuum treatment vessel means a corresponding stress on its connections and their supply lines.

Alternatively, the pans are lifted by means of suitable hoists from the ladle transport vehicle or including the ladle transport vehicle and brought to the dip tubes of permanently installed vacuum treatment vessel. This is done by Kranseilgehängen or hydraulic lifting devices that ensure an exact vertical movement of the pan, because of the desired large dip tube diameter exact positioning of the pan is to ensure with respect to the dip tubes. However, such Kranseilgehänge as well as hydraulic lifting devices are space consuming and therefore require a correspondingly large construction and intervention costs.

In the design are cheaper hoists with a movable of a hydraulic cylinder, in the lifting or the Absetzbewegung rotatable about a swivel arm. Such a swivel arm hoist is already realized for the movement of the vacuum treatment vessel of an RH plant and, for example, from the publication " Secondary Metallurgy - Fundamentals, Processes, Applications "Verlag Stahleisen GmbH, Dusseldorf, 2002 , Figure 3.2.1.5 visible.

A disadvantage of such pivoting hoists that during the rotational movement of the pivot arm inevitably not only a vertical so stroke movement of the pan carried pan is formed, but also dependent on the pivot angle and the corresponding radii horizontal movement with a horizontal displacement of the vertical axis of the pan. This kinematics would result in the use of such a pivoting mechanism for bringing a pan to the dip tubes of a vacuum treatment vessel to the diameter of the dip tubes are to be reduced accordingly to take into account the horizontal movement of the pan in their lifting or Absetzbewegung.

The abstract XP-002440928, available from the WPI (Thomson) database, to document SU 908,847 discloses a hoist with which a ladle filled with liquid metal can be raised towards a vacuum treatment vessel or dip tube of such a vessel. There is a lever construction, which must be attached to a ceiling suspension. The complex mechanism also requires a lowered floor area in which a hydraulic cylinder is arranged.

Abstract XP-002440929, available through the WPI (Thomson) database, to document SU 840,138 describes a similar device which, while capable of being installed at ground level, also requires suspension on a ceiling structure.

The invention has for its object to provide a hoist for a liquid steel-containing pan for lifting a ladle transport car to the dip tubes of the vacuum treatment vessel of an RH plant available, which on the basis of rotatable lift arms, but largely without one in the rotational movement of the Lift arms entering horizontal movement of the pan works.

The solution of this problem arises, including advantageous embodiments and refinements of the invention from the content of the claims, which are adjusted to this description.

The invention provides in its basic idea before a hoist, consisting of two at one end with trained on the pan holders to be engaged lifting arms, which are held at its other end of the bearing in a stationary support, wherein the support of a at the bearing ends of Arranged lift arms, designed as a circular arc section runway and from a runway during the rotational movement of the lifting arms axially stationary leading rolling track is such that due to the resulting in the lifting movement of the load introduction point in the support a reduction in the horizontal movement of the pan occurs. The invention has the advantage that during the rotation of the lifting arms for raising or discontinuing the pan due to the design of the support with a rolling off on a stationary Wälzbahn abraded arcuate Ablaufbahn and the associated displacement of the pivot point for the pivoting movement of the lifting arms also a horizontal displacement the lifting arms is effected, by means of which the horizontal displacement of the pan associated with the pivoting path in the lifting or Absetzbewegung the pan is compensated.

In order to take into account the considerable forces occurring, according to one embodiment of the invention, it is provided that the arcuate section-shaped Runway and the stationary Wälzbahn are provided with interlocking teeth.

Depending on the installation conditions of such a hoist can alternatively be provided to a constant radius of the arcuate section-shaped runway according to an embodiment that the radius of the circular arc section-shaped runway changes depending on the rotational position and the length of the lift arms, and that as a result the runway is curved. Thus, a better adaptation of the degree of horizontal displacement of the lifting arms in the pivot bearing in dependence on the angle of rotation is possible.

According to a preferred embodiment of the invention, it is provided that the two lifting arms are connected to one another by a cross-connection carrier which crosses over the ladle transport carriage, wherein the transverse connection carrier set in rotation by the movement of the lifting arms is held and guided in the support. Due to the symmetrical arrangement and design of the lifting arms with cross-connection carrier a good load bearing is ensured even in the support.

Alternatively, it can be provided that the arcuate section-shaped run-off track is formed directly on the cross-connection carrier itself, or that the cross-connection carrier is held in a housing box and the arcuate section-shaped runway is formed on the housing box.

As far as according to an embodiment of the invention, each of the two lift arms is acted upon by an associated hydraulic cylinder, in a further embodiment of the Invention also be provided that only one of the lifting arms associated with a hydraulic cylinder and the cross-connection carrier is formed with such a torsional stiffness, that the second lifting arm is taken in the movement of the acted upon by the hydraulic cylinder first lift arm.

To facilitate the operation and shortening of the process playing time can be provided according to an embodiment of the invention that the cross-connection carrier engages over the ladle transport car at such a height that the pan transport carriage with the pan mounted thereon can be moved under the cross-connection carrier, so that the pan transport car under the hoist free are movable.

Since the pan must remain aligned during the rotational movement of the lifting arms in each case in their vertical direction, is provided according to an embodiment of a pan formed as both sides radially projecting pin holding devices that the lifting arms at its end wiegenartige, a relative movement of the pin to the lift arms enabling recording for the pins. Thus, the pan is movably suspended with their pins in the weigh-like recordings and is also directed at a rotational movement of the lift arms each automatically in the vertical.

In an alternative embodiment, pans with pins projecting radially on both sides and lugs rotatably supported thereon are provided as holding devices, wherein the lugs are useful for hooking in crane hooks for the movement of the pans during operation. Since the tabs are rotatable with respect to the pins located on the pan, the pan aligns itself in their handling by acting on the tabs handling devices each automatically in the vertical. For this purpose, it is then provided that the lifting arms have at their ends the lugs form-fitting underarchive receptacles, so that during the lifting or settling movement of the pan and during the treatment time, the pan is elevated with the tabs in the receptacles of the lifting arms; a misalignment of the tabs in the raised treatment position of the pan is not detrimental because the pan is rotatably suspended in the tabs and therefore aligns due to the lower center of gravity in the vertical.

Fig. 1

ein Hubwerk mit einem davor stehenden Pfannentransportwagen in einer Seitenansicht,

Fig. 2

den Gegenstand der Figur 1 in einer Vorderansicht,

Fig. 3

das Hubwerk gemäß Figur 1 beim Angriff der Hubarme an der Pfanne,

Fig. 4

das Hubwerk gemäß Figuren 1 bzw. 3 bei von dem Pfannentransportwagen abgehobener und in eine obere Behandlungsstellung hochgehobener Pfanne,

Fig. 5

das Auflager mit kreisbogenabschnittsförmiger Ablaufbahn und ortsfester Wälzbahn in einer vergrößerten Einzeldarstellung,

Fig. 6

die gegenseitige Zuordnung von Pfanne und Auflager für die Hubarme in einer schematischen Seitenansicht,

Fig. 7

die Pfanne mit eine Lasche aufweisenden Haltevorrichtungen und Auflager für die Hubarme in einer schematischen Seitenansicht,

Fig. 8 u. 9

den Gegenstand der Figuren 3 und 4 in einer anderen Ausführungsform.

In the drawings, embodiments of the invention are shown, which are described below; show it:

Fig. 1

a hoist with a ladle truck in front in a side view,

Fig. 2

the object of FIG. 1 in a front view,

Fig. 3

the hoist according to FIG. 1 during the attack of the lifting arms on the pan,

Fig. 4

the hoist according to FIGS. 1 or 3 in the case of the pan lifted from the ladle transport vehicle and lifted into an upper treatment position,

Fig. 5

the support with circular arc section-shaped travel path and stationary rolling track in an enlarged detail view,

Fig. 6

the mutual assignment of pan and support for the lifting arms in a schematic side view,

Fig. 7

the pan with a tab holding fixtures and supports for the lifting arms in a schematic side view,

Fig. 8 u. 9

the object of FIGS. 3 and 4 in another embodiment.

As it turned out first Figures 1 and 2 results, is used to transport a pan 11 a ladle dolly 10, on which the pan 11 at her Handling is elevated. For engagement of handling devices during normal operation, the pan 11 is provided with laterally projecting pin 12 as a holding device in the illustrated embodiment, so that, for example, crane hooks can engage the pin 12 of the pan 11.

At 13, a hoist for the pan 11 is shown, by means of which the pan can be lifted to only schematically shown dip tubes 22 of a vacuum treatment vessel not shown zoom. The hoist 13 consists of two lifting arms 14 which can attack on both sides of the pin 12 of the pan 11. As can be seen from a synopsis of Figures 1 and 2 shows, the two lifting arms 14 are connected to each other via a cross-connection support 15, wherein the cross-connection support 15 is mounted in a housing box 16. The housing box 16 is supported by laterally arranged the path of movement for the ladle dolly 10 foundation bases 23, so that the ladle transport vehicle 10 cross portal-like device is formed as a lifting mechanism 13. In this case, the lateral foundation bases 23 are designed with such a height that the cross-connection support 15 engages over the ladle transport carriage 10 with the ladle 11 mounted thereon at such a height that the ladle transport carriage 10 with the ladle 11 resting thereon can be moved through the lifting mechanism 13.

As far as a support 17 is provided for the rotation of the lifting arms 14, the cross-connection support 15 is mounted in a housing box 16, on the undersides of each a circular arc section-shaped runway 18 is formed, which rests on a stationary Wälzbahn 19, the arcuate in the rotational movement of the lifting arms Run-path 18 leads in its longitudinal direction.

At their front end, the lifting arms 14 each have a weighing-like receptacle 20 for engaging under the pin 12 of the pan 11. by virtue of the special design of the receptacles 20, the pins 12 of the pan 11 in the weighing receptacles 20 can move relative to the lifting arms 14, so that the resting in the receptacles 20 pan 12, as will be described, automatically due to the low-lying Aligning the center of gravity with its vertical axis in the vertical direction.

At the front end of the lifting arms 14 engage hydraulic cylinder 21, which lift the lifting arms 14 and thus the pan 11 during extension. In the illustrated embodiment, each with a lifting arm 14 associated hydraulic cylinder 21 is a controlled lowering of the pan with the remaining hydraulic cylinder possible from the raised pan position in case of failure of a cylinder.

The lifting process is out of the FIGS. 3 and 4 to recognize, in FIG. 3 the operating phase is shown, in which the pan 11 is driven with its pin 12 on the weigh-like receptacles 20 of the lifting arms 14 and the lifting arms 14 are already raised by means of the hydraulic cylinder 21 so far that the pins 12 are in the weighing receptacles 20. Upon further extension of the hydraulic cylinder 21 according to FIG. 4 the pan 11 is raised in the direction of the immersion tubes 22, not shown in these figures, which due to the still to be explained special training of the support 17 for the lifting arms 14 which is given in a pivoting hoist inherent horizontal displacement of the vertical axis of the pan 11. It can be seen that in the raised position of the pan 11 according to FIG. 4 a barely noticeable, negligible in the operation horizontal displacement of the vertical axis of the pan 11 has taken place.

How to do that FIG. 5 can be seen, the circular arc-shaped path of travel 18 and the Wälzbahn 19 are each provided with a toothing 25 and 26, so that the teeth engage in the rolling movement into each other and thus the lifting arms 14 in the Supports 17 are fixed during their displacement. With 34 of the load application point of the drain path 18 is designated in the Wälzbahn 19, which moves axially during the rolling of the circular arc section-shaped runway 18 on the Wälzbahn 19 ( FIG. 7 ). This displacement causes the lifting movement to reduce the horizontal movement of the pan.

wobei mit α der bei der Hubbewegung der Pfanne 11 zu durchlaufende Schwenkwinkel bezeichnet und R₀ der Drehradius der Zapfen um das Auflager 17 ist.How out FIG. 6 recognizable, it depends on the design in particular of the radius R ₁ for the formation of the circular arc-shaped path 18, and this radius R ₁ is determined approximately by the function: $${\mathrm{R}}_{\mathrm{1}}\mathrm{=}{\mathrm{R}}_{\mathrm{0}}\mathrm{\cdot }\left(\mathrm{1}\mathrm{-}\cos \right)\mathrm{/}\mathrm{\alpha }\left(\mathrm{radians}\right)$$

where α denotes the pivot angle to be traversed during the lifting movement of the cup 11, and R _{0 is} the radius of rotation of the pins around the support 17.

The parameters R ₁ and R ₀ can be changed depending on the angle of rotation α passed through the pan 11.

As it turned out FIG. 7 results, as brackets for receiving the pan and separate lateral tabs 29 may be arranged, wherein the tabs 29 further comprise the provided pins 12 and are rotatable relative to the pin 12. At their upper end, the tabs 29 have a connecting bolt 33 for the attack of, for example, crane hooks. If the pan 11 lifted on the tabs 29, so the pan 11 is due to the rotatable mounting of the pin 12 in the tabs 29 in each case in the vertical automatically. This kinematics is in an embodiment of the invention according to FIG. 7 used for the attack of the lifting arms 14 on the pan 11 by the lifting arms 14 are provided at its associated front end with receptacles 32 which positively engage the respective lower part 30 of the tab 29, so that the pan 11 with the tabs 29 in the receptacles 32 of the lifting arms 14 positively elevated. Now, if the pan raised over the rotation of the lifting arms 14, the associated misalignment of the tabs 29 has no effect, since the pan 11 aligns automatically with the rotatably mounted in the tabs pin 12 12 in the vertical. Also in FIG. 7 is again shown how due to the extension of the pivot point of the lifting arm 14 in the support 17, a balance of the horizontal displacement of the vertical axis 27 of the pan 11 results, which occurs in the illustrated embodiment, only to a negligible extent.

At the in FIGS. 8 and 9 Finally, for better control of the forces occurring on the lifting mechanism 13, a counterweight 31 is provided on the lifting arms 14 or the housing box 16 supporting the cross-connection carrier 15.

Claims (11)

1. Hoisting mechanism (13) for lifting a ladle (11) filled with liquid steel from a ladle transfer vehicle (10) to immersion pipes (22) of a vacuum treatment vessel of an RH degasser, comprising two lifting arms (14) which are connected at one of their ends to a hydraulic cylinder (21) or to one hydraulic cylinder (21) each, and which each have a receptacle (20), which lifting arms (14) are to be brought into engagement with retaining devices (12, 29) embodied on the ladle (11), enabling a movement of the retaining devices (12, 29) relative to the lifting arms (14), characterised in that at their other end the lifting arms (14) are retained in a fixed support (17), wherein the support (17) consists of a runway (18) arranged at the other end of the lifting arms (14) and embodied as a circular arc segment and of a rolling path (19) axially fixedly guiding the runway (18) during a lifting movement of the hydraulic cylinder(s) (21) in such a way that during the lifting movement a displacement of a load introduction point (34) occurs in the support (17) in that the circular-arc-segment-shaped runway (18) has a radius (R1) around a centre point whose position varies as a function of a lifting position of the lifting arms (14).
2. Hoisting mechanism according to claim 1, characterised in that the circular-arc-segment-shaped runway (18) and the stationary rolling path (19) are provided with intermeshing teeth (25, 26).
3. Hoisting mechanism according to one of claims 1 or 2, characterised in that the two lifting arms (14) are connected to each other by means of a transverse connecting member (15) extending across the ladle transfer vehicle (10), wherein the transverse connecting member (15) set into rotation by the movement of the lifting arms (14) is retained and guided in the support (17).
4. Hoisting mechanism according to claim 3, characterised in that the circular-arc-segment-shaped runway (18) is embodied on the transverse connecting member (15).
5. Hoisting mechanism according to claim 3, characterised in that the transverse connecting member (15) is retained in a housing box (16) and the circular-arc-segment-shaped runway (18) is embodied on the housing box (16).
6. Hoisting mechanism according to one of claims 3 to 5, characterised in that a hydraulic cylinder (21) is associated with one of the lifting arms (14).
7. Hoisting mechanism according to one of claims 1 to 5, characterised in that a hydraulic cylinder (21) is associated with each of the two lifting arms (14).
8. Hoisting mechanism according to one of claims 3 to 7, characterised in that the transverse connecting member (15) extends across the ladle transfer vehicle (10) at such a height that the transfer vehicle (10) with the ladle (11) mounted thereon is movable under the transverse connecting member (15).
9. Hoisting mechanism according to one of claims 1 to 8, characterised in that the receptacles (20) enabling a relative movement with respect to the retaining devices (12, 29) are embodied as cradle-like.
10. Hoisting mechanism according to one of claims 1 to 8, characterised in that the receptacles (20) are embodied in order to secure the retaining devices (12, 29) from below in a form-fit manner.
11. Hoisting mechanism according to one of claims 1 to 10, characterised in that the lifting arms (14) are extended in length beyond the support (17) and are provided with a counterweight (31) at their end projecting beyond the support (17).

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