EP2571641B1 - Strand guide - Google Patents

Description

The invention relates to a strand guiding device for guiding a metal strand after its exit from a mold in a continuous casting plant.

A strand guiding device of the type mentioned is in the prior art, for example from the Japanese publication JP 57 139460 known. The strand guiding device disclosed therein serves to guide a metal strand after it leaves a mold in a continuous casting plant. The strand guiding device is equipped with a secondary cooling device for cooling the metal strand in the strand guiding device. The secondary cooling device comprises a pump device for pumping a cooling medium, for example cooling water, through a cooling line network to individual cooling zones distributed along the strand guide. The cooling zones each form part of the cooling line network. In the cooling zones, the cooling water is injected by means of nozzle devices onto the metal strand to be cooled in the strand guiding device. Each cooling zone is individually associated with valves for adjusting the volume flow or the pressure of the cooling water in the respective cooling zone. Furthermore, the pump device is assigned a pump control loop for regulating the pressure of the pumped by the pump cooling water. Similar disclosure contents can also be found in the Japanese publications JP 57 206559 or JP 58 077760 and the unpublished international patent application PCT / EP2010 / 004563 ,

Furthermore, in the prior art strand guiding devices are known, in which the pairs of rollers typically used for guiding the strand in so-called segments are summarized as structural units. The segments may, but need not, have variable pitch adjustment actuators; see for example DE 10 2008 009 136 A1 ,

From the German publication DE 10 2008 004 911 A1 the use of two-fluid nozzles within secondary cooling devices is known. The dual-fluid nozzles advantageously allow a variable adjustment of the proportions of two different cooling media used, for example air and cooling water.

The German Offenlegungsschrift DE 101 04 348 A1 discloses a strand guide segment with a roller carrier for guiding the casting strand. Also arranged on the roller carrier is a series of spray nozzles through which coolant is sprayed onto the strand. The cooling medium is conducted via pipelines to these nozzles. The pipelines can be connected via flanges or clamping plates to a further coolant supply network of the strand guiding device.

The Japanese publication JP 2009195959 discloses a strand guiding apparatus for guiding a metal strand after its exit from the mold in a continuous casting plant. The individual roller segments of the strand guide are associated with cooling lines, each having at least one valve and a nozzle device for spraying a coolant between two adjacent segments on the guided metal strand. The valve is over the attached to the segment pipelines also arranged quasi on the segment.

The invention has the object of developing a known strand guiding device with a secondary cooling device to the effect that the design complexity for the secondary cooling device is reduced and the secondary cooling is improved.

This object is achieved on the one hand by the subject matter of claim 1.

Accordingly, the strand guide device described in the introduction is characterized by a cooling zone pressure measuring device for detecting the actual pressure of the cooling medium in the cooling zone and a cooling zone pressure control device for determining a cooling zone pressure control difference as the difference between a predetermined cooling zone pressure setpoint and the actual pressure and for driving the valve of the cooling zone in accordance with the determined cooling zone pressure control difference for regulating the pressure to the predetermined cooling zone pressure setpoint, wherein the cooling zone pressure control device and / or the cooling zone pressure measuring device are arranged on the roller segment; or alternatively to the cooling zone pressure measuring device by a cooling zone volume flow measuring device for detecting the actual volume flow of the cooling medium in the cooling zone; and alternatively to the cooling zone pressure control device by a cooling zone volume flow control device for determining a cooling zone volume flow control difference as the difference between a predetermined cooling zone volume flow setpoint and the actual volume flow and for driving the valve of the cooling zone in accordance with the determined Cooling zone volume flow control difference for controlling the volume flow to the predetermined cooling zone volume flow setpoint, wherein the cooling zone volume flow control device and / or the cooling zone volume flow measuring device are arranged on the roller segment; and wherein the strand guiding device is further characterized by at least one second roller segment having at least one actuator for variably adjusting the jaw width of the rollers of the roller segment.

In addition to at least one first roller segment with at least partially assigned cooling zone, the strand guiding device also has at least one second roller segment with at least one actuator for variably setting the jaw width of the rollers of the roller segment. The actuator is, for example, a hydraulic cylinder. The actuators serve to realize a targeted thickness adjustment of the strand when passing through the strand guiding device. The actuators are optional for the individual segments, which means that they are not mandatory. The actuators can be arranged both on segments with associated cooling zone as well as on segments without associated cooling zone.

Due to the claimed displacement of the valves in conjunction with a shift of the cooling zone-specific pressure or volume flow control or - measuring devices on the roller segment, the length of the cooling lines between the valve and the nozzle devices or the aforementioned cooling zone-specific facilities and the Nozzle devices shorten compared to an arrangement of these components in the distribution space. Thus, the friction and flow losses are reduced within the cooling zone, thereby advantageously a more precise adjustment of the nozzle devices and their spray patterns is possible.

In traditional strand guiding devices, the complex cooling lines for the secondary cooling device were located at least predominantly within a distributor space away from the strand guiding device. However, the casting of more sophisticated grades of steel increasingly requires a greater number of cooling zones along the strand guide to maximize one To adjust individual spray pattern and cooling behavior of the cooling zones when guiding the metal strand within the strand guide device. However, the distribution space traditionally provided for the valves and the cooling lines reaches its limits in a purely capacitive manner with a larger number of intended cooling zones. Therefore, it is distributed, if according to the invention, the valves for the individual cooling zones are each arranged directly on the roller segments, because this advantageously allows a displacement of the valves and the complex cooling lines per cooling zone at least largely out of the confined distribution space taking advantage of further available space , just on the roll segments.

In the following, some of the central terms used in the description are explained in more detail:

continuous casting:

The term "continuous casting plant" means the combination of a mold and a mold guiding device downstream of the mold.

mold:

The term "mold" refers to a mold on the cooled side walls, typically made of copper, which initially cools liquid metal and forms a strand shell. By pulling out the strand shell from the mold, a metal strand with initially still liquid core is formed.

A strand guide device:

The term "strand guiding device" refers to a plurality of roller pairs, which are arranged immediately below the mold for guiding the metal strand after its exit from the mold. The metal strand is supported in the strand guide device by the pairs of rollers and led until it is further cooled and solidified. In particular, the majority of opposing pairs of rollers are referred to as strand guide.

Roller segment:

In order to make the mechanical engineering modular and to make the strand guide for maintenance manageable, a plurality of pairs of rolls of the strand guide are combined to form individual structural units, so-called roll segments. For example, seven rollers can be installed in a top frame and seven other rollers in a subframe opposite the top frame. Upper and lower frames together with their associated roles and an optional mechanical tension, for example by means of brackets for a fixed spacing or by means of hydraulic cylinders for a variable spacing, each one segment. These segments can each be installed as structural units in the strand guiding device and can be removed again for maintenance purposes. The maintenance of the segments takes place in special workshops. The terms "segment" and "role segment" are used synonymously. The term "... on the roller segment" means on or in the roller segment, preferably in the sense of a structural unit.

Segment support:

The term segment carrier typically refers to a steel structure for receiving and accurately positioning at least one, but typically a plurality of segments within the strand guiding device. In the context of the present description, the term segment carrier designates an independent component which is specifically designed and provided for receiving segments. It should not be confused or equated with other technical elements, such as foundations or frame structures, which actually have a different function. A segment carrier has bearing surfaces for the individual segments. In addition, to the Segment beams are usually fitted with clamping plates (see definition below) that supply the cooling zones with cooling media, such as cooling water or air. The term "in the region of the segment carrier" means on, at, within or in the vicinity of the segment carrier, but in any case outside the water carrier space. A segment carrier is generally used to support and receive the segments; but it is not absolutely necessary. For example, the first segment in the casting direction behind the mold can be carried by a base frame of the mold oscillation or by the second segments arranged downstream in the casting direction. Further alternatively, the segments may be stacked so that a segment is supported on the underlying one. The lowermost segment in turn rests on a foundation or frame of another product, for example a bending driver.

Primary and secondary cooling:

In continuous casting, a distinction is made between primary and secondary cooling. The primary cooling takes place in the mold by the side walls are cooled with cooling water, whereby the initially still liquid metal in the mold heat is removed. In this way, in the starting region of the mold, said strand shell forms, which envelops the still liquid metal in the interior of the mold.

The secondary cooling of the metal strand takes place within the strand guide device after the metal strand has exited the mold. Within the strand guide device, the metal strand is further cooled by spraying cooling water from outside under pressure onto the strand shell. As a result (and also by the contact of the metal strand to the rollers of the strand guide and by thermal radiation) the metal strand heat is further withdrawn and the strand shell continues to grow until the metal strand is finally completely solidified.

The primary and secondary cooling are typically controlled or regulated in separate cooling circuits.

Network of cooling pipes:

The terms "network of cooling lines" and "cooling line network" are used synonymously. Both terms designate at least one, but typically a plurality of cooling lines, typically pipelines, through which a cooling medium, typically (secondary) cooling water, flows. Via the cooling line network, the cooling medium is pumped from a pump device to nozzle devices in order to be sprayed from the nozzle devices onto the metal strand.

Chipboard:

The term "clamping plate" denotes a detachable coupling point for coupling the cooling zones on a segment to a cooling medium supply, in particular the cooling water supply. For example, at least one of the cooling lines of the cooling line network in the region of the segment carrier is welded at right angles to a flat first flange plate. Similarly, the cooling line of the cooling zone on the segment is also preferably welded at right angles to a second flange plate. The flange plates each have openings / holes for the passage of the cooling water.

When installing the segment in the strand guiding device and still positioning on the segment carrier then the two flange plates with their openings are directly opposite each other. The two opposing flange plates are sealed against each other by means of seals and thus allow a leak-free transport of the cooling medium from the pump device to a cooling zone on the segment. Not just each one of the opposing flange plates, but alternatively the two in the Built-in state of the segment opposite flange plates are referred to in the present description as a clamping plate. Not only the cooling water, but alternatively another cooling medium, for example air, for the secondary cooling can be transported to the segment via such a clamping plate. Furthermore, clamping plates can also be used as a detachable coupling point for other media lines, such as hydraulic lines.

Cooling zone:

• eine Kühlzone ist genau einem Segment zugeordnet,
• mehrere Kühlzonen sind einem Segment zugeordnet, oder
• eine Kühlzone ist auf mehrere Segmente verteilt.

The term "cooling zone" designates in each case a part of the cooling line network with associated nozzle devices. Each cooling zone is characterized by the fact that it is associated with an individual cooling zone control loop, either for flow control or for pressure control. It is characteristic that all the nozzle devices of a cooling zone are supplied together by a valve. Three cases can be distinguished:

• a cooling zone is assigned to exactly one segment,
• several cooling zones are assigned to a segment, or
• a cooling zone is distributed over several segments.

Water distribution space:

The term "water distribution space" or "distribution space" for short in traditional strand guide devices means a separate space in which the required components for adjusting the volume flow of the secondary cooling are housed. The water distribution space traditionally includes the pumping device, all necessary measuring and control device for a pump control loop and for cooling zone control loops in the strand guide device. In contrast to this traditional use of water distribution space, the water distribution space serves as part of the present Invention preferably substantially only for receiving the pump device and for receiving elements of a pump control loop. All valves, measuring devices and cooling zone control devices, concerning the individual control of the cooling media in the cooling zones on the segments, according to the present invention are arranged outside the water distribution space either in the area of the segment carrier or directly on the segments. The clamping plates, which provide for the transfer of the cooling media, in particular the cooling water to the cooling zones are not housed in the water distribution space.

- End of Definitions -

According to a first embodiment, the strand guiding device, wherein the valve for the cooling medium is arranged on the roller segment, characterized in that the roller segment forms a structural unit together with the valve for the cooling water, that at least one clamping plate as releasable coupling point of the cooling lines between the Segment carrier and the roller segment is provided; and that the unit as a whole is removable from the strand guide device. The clamping plate has the advantage that the installation and removal of a roller segment in the strand guide device is significantly simplified, because with the installation of a segment instead of a plurality of couplings between individual cooling lines, the clamping plate allows a leak-free transfer of the cooling media.

The claimed possibility to be able to expand the roller segment together with the valve arranged thereon as a structural unit or as a whole from the strand guide device, has the advantage of being able to test this structural unit as a whole. Especially in a test of Secondary cooling device can be found in this way errors in the valve or in the cooling zones or mutually excluded.

In the claimed solution for the strand guiding device according to claim 1, for example, a (number word) cooling zone per roller segment can be provided.

Alternatively, a plurality of the cooling zones may be provided which are distributed over a single one of the roller segments. In this case, the individual cooling zones can be arranged distributed in and / or transversely to the conveying direction of the metal strand above the roller segment. The provision of a plurality of the cooling zones over a single roller segment advantageously makes it possible to set very different / individual spray patterns and cooling profiles over the respective section of the metal strand passing through the strand guide in comparison to providing only one cooling zone over the segment.

The cooling zones can be either volume flow or pressure controlled.

Although either only one volume flow or pressure control can be provided per cooling zone, but within the strand guide device and in particular on a roller segment or in the region of the segment carrier, depending on the design of the local cooling zone (s), both volume flow as well as pressure controls be provided equally.

The nozzle device of the present invention may comprise either at least one single-fluid nozzle and / or at least one dual-fluid nozzle. The single-component nozzle is typically used for the use of cooling water as a cooling medium. In the case of the two-component nozzle, the two cooling media, cooling water and air, typically become a water-air mixture with the aid of a special mixing body vortexed and then sprayed by means of the two-fluid nozzle on the metal strand. In contrast to the single-fluid nozzle, the two-fluid nozzle produces a finer cooling water mist and, with the correct dosage, a higher cooling impulse of the water droplets striking the metal strand.

The nozzle device is advantageously designed as a nozzle bar with a plurality of nozzles.

Further advantageous embodiments are the subject of the dependent claims.

Figur 1

einen Querschnitt durch eine Strangführungsvorrichtung; und

Figur 2

eine schematische Veranschaulichung der Sekundärkühleinrichtung mit Anordnung der Kühlzonen-Regeleinrichtungen auf den Rollensegmenten;

zeigt.The description is a total of two figures attached, wherein

FIG. 1

a cross section through a strand guiding device; and

FIG. 2

a schematic illustration of the secondary cooling device with arrangement of the cooling zone control devices on the roller segments;

shows.

The invention will be described in detail below with reference to said figures, wherein like technical features are designated by like reference numerals.

In all figures, reference numeral 500 denotes a fictitious dividing line between a water distribution space 250 and a segment carrier or segment. The cooling medium is preferably cooling water.

FIG. 1 1 shows a continuous caster 200 having a mold 210 and a strand guiding device 100 arranged downstream of the mold. The strand guiding device serves to guide a metal strand after it leaves the mold 210. The strand guiding device 100 consists essentially of a plurality of roller segments 120-k with 1 ≦ k ≦ K and with k, K elements from N (set of natural numbers). Upper frame and lower frame of each segment are clamped together, for example via tie rods, that is screwed, or via actuators 195, preferably hydraulic cylinder. The individual roller segments 120-k are supported by at least one segment carrier 220. The segment carriers 220 can, as in FIG. 1 shown to be designed as a structural unit for a group of segments. Immediately below the mold, a secondary cooling device 110 is provided for cooling the metal strand 300 during its passage through the strand guiding device 100 in the conveying direction F.

In the distribution space 250, a pump device 116 is preferably arranged according to the present invention.

FIG. 2 1 shows an exemplary embodiment of the secondary cooling device 110 according to the invention. Accordingly, the secondary cooling device comprises the pump device 116 with a preferably associated pump control device 117. The pump control device 117 can be designed to control either the pressure or the volume flow of a cooling medium, typically cooling water, in the cooling line 112 at the outlet of the pump device to regulate each predetermined setpoints. In the case of a pressure control, the reference numeral 119 represents a pressure measuring device and in the case of a volume flow control, it represents a volumetric flow meter. As already mentioned above, the pump device 116 is together with the pump control device 117 typically arranged in a water distribution space 250 away from the strand guiding device.

The cooling medium conveyed by the pump device 116 is conveyed via a network of cooling lines 112 to cooling zones 114-i with 1≤i≤l and i, I elements from N of the associated nozzle devices 115. The nozzle devices are typically designed as nozzle bars, each with a plurality of individual nozzles either in the form of single-fluid or two-fluid nozzles. In the case of the use of two-fluid nozzles is in addition to the in FIG. 2 shown and ensured via the network of cooling lines supply of the nozzles with cooling water and the supply of the nozzles with a second medium, for example air, required. A possibly required for the second cooling medium parallel cooling pipe network is in FIG. 2 Not shown.

In FIG. 2 At least the valves 118 for the cooling medium, but preferably also their associated volume flow or pressure measuring devices 150, 170 and their associated volume flow or pressure control devices 160, 180 are arranged on the segments and further preferably together with the segments form a removable structural unit.

As in FIG. 2 Preferably, each cooling zone is preferably individually controlled to either a predetermined cooling zone volumetric flow setpoint or a predetermined cooling zone pressure setpoint. The volume flow or pressure control does not have to be uniform per segment, but can also, as in FIG. 2 shown diverge within a segment 120-2.

In the event that a cooling zone pressure setpoint is not directly specified, a conversion device 190 can be provided for converting an actual predetermined cooling zone volume flow setpoint with the aid of a predetermined pressure / flow characteristic for the respective cooling zone 114-i in FIG the cooling zone pressure setpoint. This will then, as in FIG. 2 shown transferred from the conversion device 190 to the cooling zone pressure controller 180. The conversion device 190 can be implemented as a software or hardware module in a central automation computer for the continuous casting plant, in particular for the strand guiding device. Alternatively, however, according to the present invention, it may also be arranged in the region II. Of the segment carrier 220 or directly on the segment 120, preferably together with the cooling zone pressure or volumetric flow controller 160, 180 and the valve 118.

In the segment 120-1 in FIG. 2 It is shown that the actuators 195 can also be arranged on a segment with an associated cooling zone.

When the valves are arranged on the segments, either only one cooling zone may be provided per roller segment 120-k, or a plurality of cooling zones 114-i may be provided which are distributed over a single one of the roller segments 120-2.

Regardless of whether a cooling zone is formed on the segment or not, the hydraulic cylinders 195 may be provided on the segment for variably adjusting the jaw width of the roller segment. In this case, as in FIG. 2 shown, at least one hydraulic valve 197, preferably arranged together with an associated jaw width control device 198 on the segment. The jaw width control device 198 serves to control at least one hydraulic valve 197 such that the hydraulic cylinders 195 are turned on in the desired manner. The hydraulic valve 197 is used for the variable closing or opening of a hydraulic line 113, which is coupled via a hydraulic clamping plate 199 to the segment. A hydraulic clamping plate 199 serves as a detachable coupling point between one of the segments 120-k and the segment carrier for the hydraulic line 113 Representation according to FIG. 2 For each individual hydraulic cylinder, an individually assigned hydraulic valve 197 can be provided, which can be controlled individually via the jaw width control device 198.

LIST OF REFERENCE NUMBERS

100

A strand guide device

110

Secondary cooling system

112

cooling lines

113

hydraulic lines

114-i

cooling zone

115

nozzle device

116

pump means

117

Pump control device

118

Valve for cooling medium

119

measuring device

120-k

roller segment

140 l

chipboard

150

Cooling zones volume flow-measuring device

160

Cooling zones volume flow control device

170

Cooling zone pressure measuring device

180

Cooling zone pressure control device

190

conversion device

195

Actuator for gap adjustment

197

hydraulic valve

198

Hydraulic control device

199

Hydraulic chipboard

200

continuous casting plant

210

mold

220

segment carrier

250

Water distribution space

300

metal strand

500

Dividing line (fictitious) between water valve chamber and segment carrier or segment

i

Running parameters for cooling zones with 1 ≤ i ≤ l

k

Running parameters for roller segments with 1 ≤ k ≤ K

I

Running parameters for chipboard with 1 ≤ l ≤ L

F

Conveying direction of the metal strand

Claims (10)

1. Strip guide device (100) for guiding a metal strip (300) after its exit from a mould (210) in a continuous casting plant (200), wherein the strip guide device is constructed with a secondary cooling device (110) for cooling the metal strip in the strip guide device and wherein the secondary cooling device (110) comprises:

   a network of cooling lines (112) with at least one cooling zone (114-i), which is constructed in the strip guide device, as part of the cooling line network;

   at least one nozzle device (115), which is associated with the cooling zone, for spraying a cooling medium onto the metal strip;

   a pump device (116) for pumping the cooling medium through the cooling line network to the nozzle device (115) associated with the cooling zone (114-i);

   at least one first roller segment (120-k) for guiding the metal strip after its exit from the mould, wherein the cooling zone (114-i) is at least in part associated with the roller segment;

   at least one valve (118), which is associated with the cooling zone and arranged on the roller segment, for setting the volume flow or the pressure of the cooling medium in the cooling zone (114-i).

   characterised by

   a cooling zone pressure measuring device (170) for detecting the actual pressure of the cooling medium in the cooling zone (114-i); and

   a cooling zone pressure regulating device (180) for determining a cooling zone pressure regulating difference as a difference between a predetermined cooling zone pressure target value and the actual pressure and for controlling the valve (118) of the cooling zone depending on the determined cooling zone pressure regulating difference for regulation of the pressure to the predetermined cooling zone pressure target value, wherein the cooling zone pressure regulating device (180) and/or the cooling zone pressure measuring device (170) is or are arranged on the roller segment; or

   alternatively to the cooling zone pressure measuring device a cooling zone volume flow measuring device (150) for detecting the actual volume flow of the cooling medium in the cooling zone (114-i); and

   alternatively to the cooling zone pressure regulating device a cooling zone volume flow regulating device (160) for determining a cooling zone volume flow regulating difference as a difference between a predetermined cooling zone volume flow target value and the actual volume flow and for controlling the valve (118) of the cooling zone (114-i) depending on the determined cooling zone volume flow regulating difference for regulation of the volume flow to the predetermined cooling zone volume flow target value, wherein the cooling zone volume flow regulating device (160) and/or the cooling zone volume flow measuring device (150) is or are arranged on the roller segment; and

   wherein the strip guide device is further characterised by at least one second roller segment with at least one setting element for variable setting of the mouth width of the rollers of the roller segment.
2. Strip guide device according to claim 1,
   characterised in that
   the roller segment (120-k) together with the valve (118) for the cooling water forms a constructional unit;
   at least one clamping plate (140-l) is provided between the segment carrier and the roller segment (120-k) as a detachable coupling point of the cooling lines (112); and
   the unit is demountable as a whole from the strip guide device.
3. Strip guide device (100) according to one of the preceding claims,
   characterised by
   at least one segment carrier (200) for receiving and fixing the at least one roller segment (120-k).
4. Strip guide device (100) according to any one of the preceding claims, characterised in that
   one cooling zone (114-i) is provided for each roller segment (120-k).
5. Strip guide device (100) according to any one of claims 1 to 3,
   characterised in that
   a plurality of cooling zones (114-i) arranged in distribution over an individual one of the roller segments (120-k) is provided.
6. Strip guide device (100) according to claim 5,
   characterised in that
   the cooling zones (114-i) are arranged in distribution over the roller segment (120-k) in or transversely to the conveying direction of the metal strip.
7. Strip guide device (100) according to claim 1,
   characterised in that
   at least one hydraulic valve (197), preferably together with a mouth width regulating device (198), for regulating the throughflow of hydraulic liquid for control of the hydraulic cylinder is similarly arranged on the second roller segment.
8. Strip guide device (100) according to claim 1 or 7,
   characterised in that
   the first roller segment and the second roller segment are the same and a cooling zone is associated with the roller segment.
9. Strip guide device (100) according to claim 1 or 7,
   characterised in that
   no cooling zone is associated with the second roller segment.
10. Strip guide device (100) according to any one of claims 3 to 9,
    characterised in that
    the pump device (116) is arranged away from the segment carrier and the roller segment in a water distribution space (250).

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