EP3634665B1 - Coolant nozzle for cooling a metal strand in a continuous casting installation - Google Patents

Description

The invention relates to a coolant nozzle for cooling a metallic strand in a continuous casting plant.

A continuous casting plant - for example for casting steel slabs - comprises - in a direction of passage of the strand through the continuous casting plant -, among other things, a ladle with an outlet pipe, a pouring distributor arranged below the ladle with a pouring pipe and a stopper arranged in the pouring distributor or another closure as well as a mold arranged below the casting distributor and receiving a lower end of the casting tube and having cooled broad side plates and cooled narrow side plates.

The ladle contains liquid steel, which is fed into the pouring distributor via the outlet pipe. In turn, the liquid steel is introduced from the pouring distributor via the pouring pipe into the mold, with a mass flow of the steel flowing into the mold being controlled using the stopper or another closure.

In the mold, the steel cools down (primarily) at its contact surfaces with the (cooled) broad side plates and the (cooled) narrow side plates of the mold and solidifies in the process, so that the steel emerges from the mold in the form of a strand with a rectangular cross section. Upon exiting, the strand has a solidified shell - typically - a few centimeters thick, while much of its cross-section is still liquid.

Below the mold, the strand is horizontal by means of a strand guiding system through a so-called pouring bend arranged below or downstream of the mold - and then further horizontally at the exit of the casting arch - guided or supported and guided or transported away by strand guiding system support elements, ie rollers of the strand guiding system.

At the same time, the strand is cooled by a liquid coolant (typically water, so-called "water only" cooling) or a mixture of a liquid cooling medium and a gas (so-called "air mist" cooling or air/water spraying) (secondary, "secondary Cooling"/secondary cooling) using appropriate (spray) nozzles ("water only" nozzles/"air mist" nozzles).

In the continuous casting plant, following the casting arch, there is a downstream unit, such as a flame cutting machine, by means of which the strand - for example in the form of slabs - is cut or divided.

However, the strand can also be further processed directly by a (different) downstream unit, for example a rolling stand of a combined casting and rolling plant, without being divided into pieces beforehand.

With the so-called "water only" nozzles of the secondary cooling, a cooling intensity can be adjusted in a small range depending on a coolant or water pressure. The disadvantage of this, however, is that the spray pattern also changes as a function of the water pressure, with a uniform surface temperature of the strand not being guaranteed due to inhomogeneous heat dissipation.

The aim of the so-called "air mist" nozzles of the secondary cooling is to increase the spread between the maximum and minimum flow rate of coolant through the spray nozzles; In practice, however, it has turned out that a higher spread than 10:1 for "air mist" nozzles or 3:1 for "water only" nozzles is difficult to achieve. This can for some Steel grades, however, lead to overcooling, especially of the strand edges, and thus to a loss of quality.

In addition, the energy consumption for the provision of compressed air for the "air mist" nozzles is very high, resulting in increased CO2 emissions on the one hand and higher costs for operating the system on the other.

From the DE 199 28 936 C2 such a secondary cooling is known. In this secondary cooling, the strand is cooled by intermittently spraying a coolant nozzle. The disadvantage of these coolant nozzles is that the flow through the coolant nozzles cannot be actively (set) so that, in particular, large spreads between the maximum and minimum coolant quantities that are applied to the strand through the coolant nozzles cannot be realized.

Since the edge areas of a steel strand need to be cooled to a much lesser extent than the central area of the strand in order to achieve a constant surface temperature, the use of this secondary cooling leads to overcooling, i.e. excessive cooling, of the edge areas, which reduces the quality of the steel strand.

From the AT517772A1 is a coolant nozzle for cooling a metal strand in a continuous casting plant with a mouthpiece arranged at a nozzle exit end, i.e. an outlet nozzle, a feed designed as a tube-in-tube system, through the first tube of which control air and through the second tube liquid coolant can be supplied , and a switching valve which is arranged between the mouthpiece and the feed and can be actuated pneumatically using the control air. The switching valve is - as a separate, non-integrated component - screwed from the outside onto the feed; the mouthpiece is screwed onto the switching valve from the outside.

From the EP 2 527 061 A1 discloses a coolant nozzle for cooling a metallic strand in a continuous casting plant with a mouthpiece which is arranged at a nozzle outlet end and through which liquid coolant can emerge from the coolant nozzle. The switching valve is not integrated into a feed designed as a pipe-in-pipe system.

An object of the invention is to overcome the disadvantages of the prior art and to specify a device for cooling a metallic strand with which the cooling intensity can be adjusted over a wide range in a simple, robust and energy-efficient manner.

This object is achieved by a coolant nozzle for cooling a metallic strand in a continuous casting plant with the features of the corresponding independent claim.

Advantageous developments of the invention are the subject of dependent claims and the following description.

The coolant nozzle for cooling a metallic strand in a continuous casting plant provides a nozzle arranged at a nozzle outlet end of the coolant nozzle, through which liquid coolant, in particular through a nozzle outlet opening there, can exit from the coolant nozzle.

A specially manufactured pipe end piece of any shape, size and other design can be underneath such a mouthpiece. The spray pattern of the coolant nozzle, for example a triangle, a trapezoid or a full or hollow cone, can be determined by the design of the mouthpiece outlet opening of the mouthpiece.

The mouthpiece can expediently be a detachable element of the coolant nozzle, for example one that can be detached or screwed on/screwed on using a screw connection or a thread, so that it can be used or replaced variably—depending on the desired use.

In particular, it can be provided that the mouthpiece on or with a feed, in particular a feed outlet end of the feed, this optionally as a Mouthpiece recording can be labeled, screwed or screwed there.

Further expediently, it can be provided that the mouthpiece is designed in such a way that a flow cavity in the mouthpiece, i.e. the inner cavity in the mouthpiece (between the mouthpiece inlet opening and the mouthpiece outlet opening), through which the liquid coolant flows through the mouthpiece, has a small volume has, for example, in that the mouthpiece - is designed as short as possible - in the direction of flow (of the liquid coolant through the mouthpiece).

If this cavity is designed as small as possible, only a small amount of coolant can collect there - with the coolant nozzle blocked - ("dead space/dead space volume"), the escape of which - which cannot be controlled by switching off - is undesirable (at least to a large extent). This also enables the liquid coolant to build up pressure more quickly in the coolant nozzle.

Furthermore, the coolant nozzle has a supply configured as a pipe-in-pipe system and arranged upstream of the mouthpiece in the direction of flow with a supply outlet end, through the first pipe of which control air can be fed to the supply outlet end and through the second pipe of which the liquid coolant can flow via the supply outlet end Mouthpiece can be fed.

A pipe-in-pipe system can be understood as an arrangement of (at least) two pipes, ie (at least) a first pipe and a second pipe, one pipe of the (at least) two pipes, namely the first pipe, inside the other tube of the (at least) two tubes, namely the second tube ("tube-in-tube").

To put it simply and clearly, in the pipe-in-pipe system (in the "pipe-in-pipe" area), the first pipe ("inner pipe") (completely surrounded by the second pipe) lies in the second pipe ("outer" or "Outer tube") surrounding the inner tube, with a cavity being formed between the outer wall surface of the inner tube and the inner wall surface of the outer tube.

A tube may be understood as an elongate hollow body, the length of which is generally significantly greater than its diameter.

The pipe-in-pipe system of the coolant nozzle avoids external hoses or pipes, i.e. outside the coolant nozzle, for supplying the control air, which makes the assembly and disassembly of a coolant nozzle much easier in a tight line guide. The internal supply of the control air also increases the reliability of the coolant nozzle.

In addition, the tube-in-tube system increases the mechanical strength of the coolant nozzle.

The tube or the hollow body of the tube-in-tube system or the coolant nozzle may be in one piece or consist of several or many (assembled) parts/elements. Likewise, the tube or the hollow body may have variable/changing diameters, i.e. inner and/or outer diameters, over its length.

Thus, according to a preferred development, it can be provided that the first pipe and/or the second pipe are/is designed in multiple parts, in particular in such a multi-part design are or is that their parts can be screwed or welded together. In particular, the screwable multi-part design of the tubes of the tube-in-tube system enables an extremely flexible design of the coolant nozzle. In addition, parts of the coolant nozzle can be easily replaced, which simplifies maintenance.

Furthermore, the pipes - used in the pipe-in-pipe system - do not require that these are bodies with essentially round and/or circular cross-sections (both for the "external cross-section" ("external cross-sectional profile") and for the "internal cross-section" (cross-sectional shape of the "internal cavity"). Any cross-sectional shape, such as - in addition to a round or circular cross-section - an oval, rectangular and/or cross-section composed of round and straight elements is possible for the pipes meant here.

This "pipe-in-pipe" arrangement of the (at least) two pipes in the feed can create two flow paths (in/through the feed) - for the control air and for the liquid coolant - the first of which through the inner Tube (i.e., inside the inner tube) - for the control air - and its second outside the inner tube and inside the outer tube, i.e., between the outer wall surface of the inner tube and the inner wall surface of the outer tube, - for the liquid Coolant - run.

The coolant nozzle thus enables - due to its structural design of the pipe-in-pipe system in the supply - the control air, for example instrument air, nitrogen or another, preferably non-flammable, gaseous pressure medium, and the liquid coolant just behind the nozzle outlet end, i.e up to the mouthpiece.

Instrument air should be understood to mean a wide variety of gases, such as ambient air, technically clean air, but also nitrogen, which are used to control pneumatic valves.

A special configuration of such a pipe-in-pipe system, for example and preferred because it can be realized structurally in a simple manner, may be seen as a concentric pipe-in-pipe system in which (at least in the "pipe-in-pipe " area) the inner tube - concentric to the outer tube - is arranged in the outer tube.

Furthermore, it may be provided that the feed is designed in a straight line or is designed to have at least one bend. A length of the feed may also be variable. As a result, coolant nozzles of the most varied of lengths and shapes can be realized—in a flexible and advantageous manner.

The coolant nozzle also has a switching valve, which is arranged at the feed outlet end and can be actuated pneumatically using the control air, for controlling the feed of the liquid coolant into the mouthpiece.

Expressed clearly and simply, the coolant nozzle provides a pneumatic switch valve (flow control valve) for controlling the coolant flow through the nozzle, which can be actuated by the control air, for example instrument air, and through which the liquid coolant can flow.

This pneumatic switching valve is located at the coolant nozzle at the feed outlet end of the feed of the coolant nozzle—and thus—in the direction of flow—in front of the mouthpiece of the coolant nozzle.

The switching valve is integrated into the supply, i.e. elements of the switching valve are also elements of the supply. For example, a valve housing—or a component part of the valve housing—can also be an element of the feed, for example a part of the inner or outer tube.

This "arranged at the supply outlet end" in the case of the switching valve also does not rule out that parts of the switching valve (in the direction of flow) are or are arranged immediately after the supply outlet end on this, for example between the supply outlet end and the mouthpiece or a mouthpiece inlet/opening . As well as the fact that parts of the switching valve are arranged immediately after the feed outlet end at this end and already in the area of the mouthpiece inlet/opening.

In other words, or the other way around, this "arranged at the supply outlet end" in the case of the switching valve also includes parts of the switching valve (in the direction of flow) immediately before the supply outlet end, i.e. in the supply or in the pipe-in-pipe system this are arranged, according to the invention integrated - as a part of the inner or outer tube - in the feed or in the pipe-in-pipe system immediately before the feed outlet end.

The switching valve can thus be opened and closed (intermittently) - controlled and actuated accordingly by the control air - whereby the coolant flow or the volume flow of the liquid coolant through the nozzle - depending on a desired cooling capacity - can be controlled or regulated.

To put it simply and clearly, control air is due to the - pneumatically actuated by the control air, from which through which liquid coolant can flow - switching valve on, the switching valve is closed - and the liquid coolant cannot flow through the valve and on to the mouthpiece of the coolant nozzle; if there is no control air at the switching valve, which can be actuated pneumatically by the control air and through which the liquid coolant can flow, the switching valve is open and the liquid coolant can flow via the valve and on to the mouthpiece of the coolant nozzle.

The control air can be applied to the valve using a pre-valve, which can in particular also be pneumatically controlled.

A pressure of the control air--which can be actuated by the switching valve--is expediently greater than the pressure of the liquid coolant--controlled by the switching valve--for example 1.5 times as large.

It is also expedient for the switching valve to be actuated, such as its (intermittent) opening and closing, by means of a switching element of the switching valve, which is designed as a control piston of a seat valve, with the flow of the cooling medium through the switching valve being either opened or closed depending on the position of the switching element becomes.

An open position of the switching element can be understood as meaning that position in which the flow of the cooling medium through the switching valve is open; on the other hand, a closed position of the switching element can be understood to mean that position in which the flow of the cooling medium through the switching valve is closed.

By actuating the switching element - when the switching valve is actuated or when the switching valve is opened and closed the switching element is typically displaced by the control air, in particular in or against the flow direction of the liquid coolant through the coolant nozzle, and then closes/blocks the coolant flow through the coolant nozzle or releases it.

However, switching valves are also known to those skilled in the art in which the switching element is rotated when it is actuated.

In principle, it is possible to design the switching valve as a slide valve or, according to the invention, as a seat valve. The advantage of the design as a seat valve is that the cooling medium is sealed without leaks without additional valves and that there is greater insensitivity to contamination.

In the design of the switching valve as a seat valve, it is advantageous if the switching element comprises a control piston, with a (corrugated) bellows or a membrane the control piston - in particular opposite the supply, for example the inner and / or the outer tube, or the valve housing - Leads and seals if necessary.

The membrane or the (corrugated) bellows is preferably made of stainless metal, preferably steel, or plastic, preferably heat-resistant plastic that has significant strength at temperatures above 250°C, such as polyimide or polyaryletherketone (PEEK).

It is preferably provided that the (corrugated) bellows is arranged concentrically on the first and inner pipe of the pipe-in-pipe system, in particular on a second part of the inner pipe designed as a corrugated bellows stop, whereby the (corrugated) Bellows can be guided axially relative to the inner tube, in particular to the corrugated bellows stop.

To put it simply and clearly, the inner or first tube represents a kind of linear guide for the (corrugated) bellows.

Appropriately, it can also be provided that the feed outlet end, in particular the mouthpiece receptacle, is designed as a valve seat for the switching element of the switching valve, in particular for the control piston of the seat valve, so that a very small coolant nozzle can be implemented.

Preferably, it can also be provided that a material of the switching element, in particular of the control piston, and a material of the valve seat are matched to one another, in particular that the valve seat has a lower hardness than the switching element or that the valve seat has a higher hardness than the switching element, wherein the part with the lower hardness is in particular annealed, the tightness of the valve and also its service life can be increased by such a material pairing.

According to a further preferred development, a connection block is provided, which can in particular be screwed to the feed line and has in particular a first connection for the control air and/or a second connection for the liquid coolant.

The connector block may further comprise a first passage, using which the first connector can be connected to the first inner tube of the feed, and/or a second passage, using which the second connector can be connected to the second tube of the feed.

With such a connection block for the coolant nozzle, the coolant nozzle implements a structurally simple and flexible, because modular, design of the coolant nozzle - with the feeder, the mouthpiece and the connection block as modules. The individual modules can be easily and quickly assembled or disassembled at any time.

Likewise, the coolant nozzle itself can also be easily assembled and disassembled, which enables the coolant nozzle to be replaced quickly (within a plant or continuous casting plant).

In order to increase the cooling capacity, it is expedient to provide several of the coolant nozzles—combined in a superordinate (structural) unit—in particular in a continuous casting plant.

For example, a cooling device for cooling a metal strand can be provided in a continuous casting plant, which has a plurality of nozzle units arranged one after the other in the strand conveying direction, in particular extending transversely to the strand conveying direction, for example a plurality of spray bars. Each of these nozzle units or each such spray bar can then provide at least a first such coolant nozzle and a second such coolant nozzle, as described.

However, each of these nozzle units or each such spray bar can preferably also provide a plurality or a multiplicity of such coolant nozzles.

By means of a common control air supply for specific coolant nozzles in each case, it is then possible to combine (specific) coolant nozzles into specific groups, such as edge nozzles (for edge areas of the strand) or nozzles for a central area in the middle of the strand.

A pilot control valve for the (activation) control of such a nozzle group as a whole can then be seated in such a common control air supply.

According to a preferred development, it can be provided that the first coolant nozzles of the plurality of nozzle units can be supplied with the control air via a first common control air supply and/or the second coolant nozzles of the plurality of nozzle units can be supplied with the control air via a second common control air supply.

Furthermore, it can also be provided that the control air supply in the first common control air supply is controlled using a first control valve arranged in the first common control air supply and/or the control air supply in the second common control air supply is controlled using a second control valve arranged in the second common control air supply .

The coolant nozzle described - in the sole arrangement and also in a superordinate combination/connection - has numerous special advantages due to its construction.

The design of the coolant nozzle enables the control air and the liquid coolant to be brought just behind the nozzle outlet end, i.e. up to the mouthpiece, so that the full pressure of the liquid coolant is immediately available when the switching valve is open (apart from small pressure drops in the switching valve, which however, can be neglected) is in contact with the coolant nozzle or rapid pressure build-up of the liquid coolant in the coolant nozzle is possible, so that a constant spray pattern is ensured even at low cooling capacities.

It is thus also possible with the coolant nozzle to increase the control range beyond the previously possible control range of 1:10 or 1:3.

Furthermore, the use of "air mist" nozzles can be largely dispensed with, so that the strand cooling is much more energy-efficient.

However, the coolant nozzle is by no means limited to a "water only" nozzle; rather, of course, an "air mist" nozzle can also be used.

Furthermore, the coolant nozzle allows - also due to its structural design - a modular design, which - allows the simple and / or quick and / or so inexpensive exchange of individual components - especially in the case of maintenance or changed application / application.

The description given so far of advantageous configurations of the invention contains numerous method features which, formulated objectively, can also be seen as a property of the corresponding device unit and vice versa.

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

The characteristics, features and advantages of the invention described above and the manner in which they are achieved will become clearer and more clearly understood in connection with the following description of the exemplary embodiments of the invention, which are explained in more detail in connection with the drawings. The exemplary embodiments serve to explain the invention and do not limit the invention to the combinations of features specified therein, not even in relation to functional features. In addition, suitable features of each exemplary embodiment can also be explicitly considered in isolation, removed from one exemplary embodiment, introduced into another exemplary embodiment to supplement it and combined with any of the claims.

FIG 1

eine schematische Darstellung einer Stranggussanlage mit einer Kühleinrichtung

FIG 2

einen schematischen Schnitt durch die Stranggussanlage aus FIG 1 entlang der dortigen Schnittebene II-II;

FIG 3

eine pneumatisch steuerbare Kühlmitteldüse für eine Düseneinheit einer Kühleinrichtung der Stranggussanlage aus FIG 1;

FIG 4

die pneumatisch steuerbare Kühlmitteldüse für eine Düseneinheit einer Kühleinrichtung der Stranggussanlage aus FIG 1 mit einer gebogenen Zuführung;

FIG 5

eine schematische Ansicht einer weiteren Kühleinrichtung für eine Kühlzone für die Stranggussanlage aus FIG 1.

Show it:

FIG 1

a schematic representation of a continuous casting plant with a cooling device

FIG 2

a schematic section through the continuous casting plant FIG 1 along the cutting plane II-II there;

3

a pneumatically controllable coolant nozzle for a nozzle unit of a cooling device of the continuous casting plant FIG 1 ;

FIG 4

the pneumatically controllable coolant nozzle for a nozzle unit of a cooling device of the continuous casting plant FIG 1 with a curved feeder;

FIG 5

a schematic view of a further cooling device for a cooling zone for the continuous casting plant FIG 1 .

FIG 1 shows a continuous casting plant 3 in a schematic representation. The continuous casting plant 3 can be a plant for casting steel slabs, for example.

The continuous casting plant 3 comprises, among other things, a ladle 30 with an outlet pipe 31. The continuous casting plant 3 also comprises a pouring distributor 32 arranged below the ladle 30 with a pouring pipe 33 and a stopper 34 arranged in the pouring distributor 32.

In addition, the continuous casting plant 3 includes a mold 35 which has four water-cooled mold plates 36 made of copper and has a rectangular cross-sectional shape. In FIG 1 only two of the four mold plates 36 are visible.

In addition, the continuous casting plant 3 includes a plurality of driven transport rollers 37 for guiding and supporting a strand, which form elements of a strand guide of the continuous casting plant 3 .

In addition, the continuous casting plant 3 has a downstream unit, not shown in the figures, such as a flame cutting machine.

In the ladle 30 there is liquid steel 38 which is introduced into the pouring distributor 32 via the outlet pipe 31 . In turn, the liquid steel 38 is introduced from the pouring distributor 32 via the pouring pipe 33 into the mold 35 , a mass flow of the steel 38 flowing into the mold 35 being controlled with the aid of the plug 34 .

In the mold 35, the steel 38 cools down at its contact surfaces with the water-cooled mold plates 36 and solidifies in this case, so that the steel 38 emerges from the mold 35 in the form of a strand 2 with a rectangular cross section.

On leaving the mold 35, the strand 2 has a solidified shell a few millimeters thick, while most of its cross-section is still liquid. Its surface temperature is in the order of around 1000 °C.

The strand 2 emerging from the mold 35 is transported away with the aid of the transport rollers 37 and guided to the previously mentioned (not shown in the figure) subsequent unit, by means of which the strand 2 is cut, for example in the form of slabs, and then transported away. Alternatively, the strand 2 could be further processed directly by a (different) downstream unit, for example a rolling stand of a combined casting and rolling plant, without first being divided into slabs.

Furthermore, the continuous casting plant 3 has a cooling device 50 for cooling the strand 2 .

The cooling device 50 comprises sixteen nozzle units 40 arranged one after the other in the strand conveying direction 51 for cooling the strand 2 from a first side (upper side according to the drawing). Of these nozzle units 40, four nozzle units 40 that follow one another in the strand conveying direction 51 belong to a common cooling zone 39 of the cooling device 50. This means that said sixteen nozzle units 40 are divided into four cooling zones 39, each with four nozzle units 40 (cf. also 5 ).

According to the FIG 1 each cooling zone 39 is assigned its own coolant pump 54, a main coolant supply line 55 connected to its coolant pump 54, from which four individual coolant supply lines 56 branch off, each connected to one of the nozzle units 40 are. Usually, however, a single coolant pump supplies coolant to a number of cooling zones via a main supply line. The branching of the coolant or the setting of the pressure or the flow rate in the individual coolant supply lines 56 of the cooling zones takes place, for example, by means of control valves.

The nozzle units 40 each have a row of a plurality of coolant nozzles 1 which follow one another perpendicularly to the strand conveying direction 51, ie in the transverse direction 52 of the strand conveying (cf. FIG 2 ).

In addition, the coolant nozzles 1 in the present exemplary embodiment each have a switching valve 14 (cf. 3 ) on.

Furthermore, the cooling device 50 has a control unit 47 . Said switching valves 14 can be controlled/switched via this control unit 47 (not shown in the figure in FIG 1 shown (cf. 5 )).

In addition, the cooling device 50 comprises, as shown, sixteen nozzle units 40 arranged one after the other in the strand conveying direction 51 for cooling the strand 2 from a second side (bottom according to the drawing) which is opposite the first side. These nozzle units 40 also each have a switching valve 14 that can be switched/actuated pneumatically via the control unit 47 (cf. 3 ) on.

Of the last-mentioned sixteen nozzle units 40, four nozzle units 40 that follow one another in the strand conveying direction 51 each belong to a common cooling zone (cf. also 5 ) .

Also, each of these cooling zones has its own coolant pump, a main coolant supply line connected to its coolant pump, from which four individual coolant supply lines branch off, these elements not being shown in the figure for the sake of clarity.

The number of nozzle units 40 per strand side - in the present case sixteen - and their numerical division into several cooling zones 39 - in the present case four cooling zones 39 per strand side - is chosen only as an example. This means that the continuous casting plant 3 could in principle have a different number of nozzle units 40 and/or a different number of cooling zones 39 .

In addition, the cooling device 50 can include a temperature measuring device, not shown, for example a pyrometer, for non-contact temperature measurement of a surface temperature of the strand 2. The temperature measuring device can be connected to the control unit 47 via a data line. However, a temperature measurement is not absolutely necessary. As an alternative to the temperature measuring device, the cooling device 50 can include a cooling model (cf. ^DYNACS® ), which calculates the required water quantities in the cooling zones in real time without measuring the temperatures.

In principle, the cooling device 50 can have several such temperature measuring devices. For example, at least one temperature measuring device can be provided both on the first side of the strand 2 and on the second side of the strand 2 .

While the strand 2 is being transported away to said downstream unit, the nozzle units 40, more precisely their coolant nozzles 1, spray a coolant 6 onto the surface 57 of the strand. In this way, the strand 2 is cooled and continues to solidify in the strand conveying direction 51 . In the present case, the coolant 6 is water.

Each of the nozzle assemblies 40 applies a predetermined/adjustable amount of coolant to the strand surface 57 . The respective amount of coolant is controlled via the switching valve 14 of the respective coolant nozzle 1 (in amount and time).

The temperature measuring device measures a surface temperature of the strand 2 and transmits the measured surface temperature to the control unit 47. Depending on the determined surface temperature and a predetermined surface temperature target value, the control unit 47 controls the coolant quantities applied by the coolant nozzles 1 to the strand 2 via the switching valves 14 in such a way that the surface temperature of the strand 2 corresponds to or approaches the specified surface temperature setpoint.

The nozzle units 40 on the second side (the lower side according to the drawing) of the strand 2 and the coolant nozzles there are operated in the same way.

In addition, FIG 1 a vertical sectional plane II-II is shown, which runs perpendicular to the strand conveying direction 51 in the end region of the strand guide through the continuous casting plant 3.

FIG 2 shows a schematic section through the continuous casting plant 3 FIG 1 along the cutting plane II-II there.

In FIG 2 the strand 2 and one of the nozzle units 40 are shown as an example.

It can be seen from this figure that the nozzle unit 40 shown has a row of several—here by way of example five—successive coolant nozzles 1 has (therefore the nozzle unit 40 can also be called a spray bar 40), the strand conveying direction 51 in the region of the nozzle unit 40 shown being perpendicular to the plane of the drawing FIG 2 is.

The coolant 6 comes in the form of cones ("coolant cones", the shape can be determined via the mouthpiece 5 of the respective coolant nozzle 1 (cf. 3 )) from the coolant nozzles 1. In the present case, the coolant cones touch at the strand surface 57. In principle, it is also possible for the coolant cones to overlap.

It can also be seen that the nozzle unit 40 shown for its five coolant nozzles 1 or for their respective pneumatically controllable switching valve 14 (cf. 3 ) has a common control air supply 43, here instrument air, with a common pilot valve 45, whereby the application of coolant to the strand surface 57--for these five coolant nozzles 1--is jointly controllable. The coolant 6 is supplied to the coolant nozzles 1 via the individual coolant supply line 56 .

3 shows the pneumatically controllable coolant nozzle 1 in detail.

The coolant nozzle 1 has three main components (modules), namely (arranged one behind the other in the direction of flow 7) a connection block 17 (arranged at the nozzle inlet end), a feed 8 (forming the central part 65 of the coolant nozzle 1) and a mouthpiece 5 (arranged at the nozzle outlet end 4). .

These three modules can be screwed together in a pressure-tight manner via screw connections 21, and can therefore be easily assembled/disassembled and exchanged. As an alternative to screw connections 21, weldable connections are suitable.

The connection block 17 is used to connect the coolant nozzle 1 to the common control air supply 43 (for the control air 13 for actuating/switching the coolant nozzle 1) and to the individual coolant supply line 56 (for the coolant 6 for strand cooling) (see also FIG 1 ).

For this purpose, the connection block 17 has a first connection 24 running perpendicularly to the direction of flow 7 of the control air 13 (through the coolant nozzle 1), by means of which - sealed by means of a seal 22, here an O-ring 22 - the connection block 17 is connected to the common control air supply 43 is connected. The control air 13 enters - perpendicularly to the flow direction 7 - via this first connection 24 into the connection block 17, is guided in the connection block 17 via a first passage 26 (here also deflected in the flow direction 7) and flows into a first part 11a of a - Two-part design - inner (first) pipe 11 as a pipe-in-pipe system 9 (from the (two-part) inner (first) pipe 11, 11a, 11b and a (also two-part) outer (second) pipe 12, 12a, 12b ) trained feeder 8 a.

For this purpose, this first part 11a of the inner tube 11 of the feed 8 is inserted into a bore 58 of the connection block 17 running in the direction of flow 7 and sealed off by means of an O-ring 22 .

The connection block 17 also provides a second connection 25 running perpendicularly to the flow direction 7 of the coolant 6 (through the coolant nozzle 1), by means of which - sealed by means of a seal 22, here also an O-ring 22 - the connection block 17 is connected to the individual Coolant supply line 56 is connected. The coolant 6 enters the connection block 17 perpendicularly to the direction of flow 7 via this second connection 25 and is guided in the connection block 17 via a second passage 27 (here also in the direction of flow 7 deflected) and flows into the first part 12a of the—two-part—outer (second) pipe 12 of the feed 8 designed as a pipe-in-pipe system 9 .

For this purpose, this first part 12a of the outer (second) pipe 12 of the feed 8 is inserted into a bore 58 of the connection block 17 running in the direction of flow 7 and (by means of an external thread on the first part 12a of the outer (second) pipe and an internal thread the hole 58) screwed.

Thus, the control air 13 and the coolant 6 can first enter the connection block 17 - which is therefore very compact - are deflected in this (in the direction of flow 7), can exit again from the connection block 17 (in the direction of flow 7) and flow - pressure-tight from the feeder 8 into the feeder 8 - (there via its feeder inlet end 66).

The feed 8 is as the - concentric - tube-in-tube system 9 - from the (two-part) inner (first) tube 11 with the two partial tubes 11a and 11b and the (also two-part) arranged concentrically to the inner tube 11 outer tube 12 formed with the two partial tubes 12a, 12b.

Via this inner pipe 11, 11a, 11b, the control air 13 is guided to the switching valve 14, here a seat valve, which is arranged at the feed outlet end 10 in the feed 8; The coolant 6 is introduced via this outer tube 12, 12a, 112b via the feed outlet end 10 of the feed 8 into the mouthpiece 5--screwed to the feed 8 at its feed outlet end 10.

The coolant nozzle 1 thus allows - due to its structural design of the pipe-in-pipe system 9 at the feed 8 -, the control air 13 and the coolant 6 just behind the nozzle outlet end 4 or bring up to the mouthpiece 5.

The design of the mouthpiece outlet opening 67 can determine the pointed image of the coolant nozzle 1, such as the coolant cone here.

The respective two sub-tubes 11a and 11b or 12a and 12b of the inner tube 11 or of the outer tube 12 are each screwed together in a pressure-tight manner (21); In addition, the first and the second partial pipe 11a and 11b of the inner pipe 11 are also glued or welded to one another.

At the feed outlet end 10 sits as 3 shows the switching valve 14 that can be actuated/switched pneumatically by means of the control air 13, which is designed as a seat valve - with a switching element 15 designed as a control piston 15 (switchable by the control air 13) - and the coolant outflow from the outer tube 12 or from the second Part 12b of the outer tube 12 of the feed 8 blocks (here the control piston 15 is pressed by the control air 13 (from the inner tube 11) into the valve seat 20 of the seat valve 14) or releases it.

For this purpose, the switching valve/seat valve 14 provides that the control piston 15 by means of a (corrugated) bellows 16 (made of steel) in relation to the feed 8, i.e. here the inner tube 11 or the second part 11b of the inner tube 11, axially/ is guided (and sealed) linearly in the direction of flow 7 (as in a linear guide).

The (corrugated) bellows 16 sits concentrically (via a fit) on the second part 11b of the inner tube 11, which has a (corrugated) stop 18 for a (corrugated) bellows support 19 carrying the (corrugated) bellows 16 supporting sleeve 69 provides.

This sleeve 69 is pressure-tightly screwed and glued to the second part 11b of the inner tube 11 (with a front end 70 of the sleeve 69 up to the (corrugated bellows) stop 18). A shoulder 72 of the (wave) bellows support 19 is supported on the rear end 71 of the sleeve 69 .

On the shoulder 72 opposite end of the (corrugated) bellows carrier 19 is the (corrugated) bellows 16 - with its first end in the flow direction 7 - placed pressure-tight; with its second end - in the direction of flow 7 - the (corrugated) bellows 16 is placed pressure-tight on the control piston 15, which is arranged immediately (in the direction of flow 7) in front of the outlet end 73 of the second part 11b of the inner tube 11.

If the control air 13 now exits via this outlet end 73 of the second part 11b of the inner tube 11, it displaces the control piston 15 axially into its valve seat 20 (with the (corrugated) bellows 16 being stretched). If no more control air 13 or no more control air pressure is applied to the control piston 15 , the (corrugated) bellows 16 contracts again to its original shape, with the control piston 15 releasing itself from its valve seat 20 .

The valve seat 20--a likewise tubular component (forming the feed outlet end 10 of the feed 8) with a through hole 74 for the coolant 6--is braced in a pressure-tight manner against the outlet end 76 of the second part 12b of the outer tube 12 by means of an outer sleeve 75.

As 3 then further shows, the mouthpiece 5 is screwed pressure-tight onto the valve seat 20 (also mouthpiece receptacle 20).

The material of the control piston 15 and the material of the valve seat 20 are coordinated in such a way that the Valve seat 20 has a lower hardness than the control piston 15.

FIG 4 shows the pneumatically controllable coolant nozzle 1 in a further representation/embodiment, which provides the feed 8 with a double bend 23 .

The description of this coolant nozzle 1 is primarily limited to the differences from the previously described coolant nozzle 1, to which reference is made with regard to features and functions that remain the same (cf. 3 and associated explanations). Elements that are essentially the same or that correspond to one another are denoted by the same reference symbols, insofar as this is expedient, and features that have not been mentioned have been adopted for the description of this coolant nozzle 1 without being described again.

As FIG 4 the feed is clarified a first time (in the inflow area of the feed 8) - by a first bending angle of approx. 20° - and a further, second time (in the outflow area) - by a second bending angle 60 of also approx. 20°.

Other first and second bending angles 59, 60 - also different first and second bending angles 59 and 60 as well as even more bends with corresponding bending angles can be realized in the feeder 8 - depending on the application.

A wide variety of coolant nozzle configurations can be implemented easily and extremely flexibly via differently designed bending angles 59, 60 in the feed 8 and via different lengths 61 in the feed 8 itself (the exchange of a feed 8 is possible without any problems due to the screwable modular design).

The terminal block 17 has how FIG 4 also shows, in this case, an axial through bore 77, in which the first part 11a of the inner tube 11 is inserted or pushed through. The end 78 of the first part 11a of the inner tube 11, which protrudes from the connection block 17, is welded to the connection block 17 (79).

5 shows schematically a - with regard to the supply of the control air 13 - more complex, but more flexible design - cooling device 50, by means of which different cooling requirements, in particular with regard to the applicable amount of coolant, to the strand 2 or its width, can be done satisfactorily.

Thus, for example (in the transverse direction 52 of the strand conveyor), outside or outer strand regions require a smaller quantity of cooling/medium than inside ones.

The description of this cooling device 50 (with the coolant nozzles 1) is primarily limited to the differences from the previously described cooling device 50 (cf. 1 and 2 ) referenced for consistent features and functionality. Elements that are essentially the same or that correspond to one another are denoted by the same reference symbols, insofar as this is expedient, and features that are not mentioned have been adopted for the description of this cooling device 50 without being described again.

As 5 for a cooling zone 39 (shown here is the one side 68 of symmetry of the cooling device 50, which is symmetrical to the strand center line 62) - made up of a total of four nozzle units 40 or spray bars 40 (in the strand conveying direction 51) each with eight coolant nozzles 1 (in the transverse strand conveying direction 52) of the cooling device 50 - clarified , this cooling device 50 sees three different control zones for this cooling zone 39 (symmetrical to the strand center line 62). 63a or 63b or 63c, all of which can be controlled via the control unit 47.

The outermost (first) coolant nozzles 41 of the four spray beams 40 (on the left and right--with respect to the transverse direction 52 of strand conveying) are connected via a (first) common control air supply 43.

Is in this (first) common control air supply 43, such as 5 shows a (first) pilot valve 45, for example pneumatically controllable by means of the control unit 47, these (left and right) outermost (first) coolant nozzles 41 of the four spray bars 40 in this cooling zone 39 can be used together (and independently of the coolant nozzles 1 of these Cooling device 50) are controlled and operated.

Correspondingly, how 5 also made clear, the second outermost (second) coolant nozzles 42 of the four spray bars 40 are connected via a (second) common control air supply 44 (with (second pilot control valve 46) arranged there) - and can thus (by the control unit 47) be controlled and actuated together.

All other - middle (third) - coolant nozzles 48 or 48a and 48b of the four spray bars 40 are also connected via a (third) common control air supply 49 (connected to the third pilot valve 53 arranged there) - and can thus (by the control unit 47) be controlled together and be actuated.

The coolant is supplied to the coolant nozzles 1 or 41, 42, 48 via the main coolant supply line 55 and individual coolant supply lines 56 (see FIG. 1 and FIG 2 ).

Since the coolant nozzles 1 are typically arranged directly on a strand guide segment between strand guide rollers are, it is favorable for the reliability of the control unit 47 and/or the pilot valves 45, 46, 53 if these are arranged away from the strand guide on the so-called mainland of the continuous casting installation. As a result, they are not exposed to high temperatures or high humidity, and on the other hand, for example, individual pilot valves can also be replaced while the plant is in operation without the continuous casting having to be interrupted.

In order to be able to connect or disconnect the control air quickly when changing segments, it is advantageous if the control air is routed from the mainland with the pilot valves 45, 46, 53 to the strand guide segment via pneumatic quick-release couplings.

Although the invention has been 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 as defined by the claims.

Reference List

1

coolant nozzle

2

(metallic) strand

3

continuous casting plant

4

nozzle exit end

5

mouthpiece

6

coolant

7

flow direction

8th

feeding

9

Pipe-in-pipe system

10

feed exit end

11

first pipe, inner pipe (for control air)

11a

first part of the first/inner tube

11b

second part of the first/inner tube

12

second tube, outer tube (for coolant)

12a

first part of the second/outer tube

12b

second part of the second/outer tube

13

control air

14

Switching valve, poppet valve, valve unit

15

switching element, control piston

16

(Corrugated) bellows

17

terminal block

18

(Bellows) stop

19

(Wave) bellows support

20

Mouthpiece receptacle, valve seat

21

screw connection

21a

glued screw connection

22

Gasket, O-ring

23

bend (of (8))

24

first connection

25

second connection

26

first implementation

27

second execution

30

Pan

31

outlet pipe

32

casting spreader

33

pouring tube

34

Plug

35

mold

36

mold plate

37

transport roller

38

steel

39

cooling zone

40

Nozzle unit, spray bar

41

first coolant nozzle (1)

42

second coolant nozzle (1)

43

(first) common control air supply

44

second common control air supply

45

(first) (pilot) control valve

46

second (pilot) control valve

47

control unit

48, 48a, 48b

additional (third) coolant nozzles (1)

49

third common control air supply

50

cooling device

51

strand conveying direction

52

Cross conveyor direction

53

third control valve

54

coolant pump

55

Main coolant supply line

56

individual coolant supply line

57

strand surface

58

drilling

59

first bend angle

60

second bend angle

61

length

62

strand centerline

63a

(first) control zone

63b

(second) tax zone

63c

(third) tax zone

64

nozzle entry end

65

center part

66

feed entry end

67

mouthpiece exit opening

68

first side of symmetry

69

sleeve

70

front end

71

rear end

72

shoulder

73

exit end

74

through hole

75

outer sleeve

76

exit end

77

through hole

78

outstanding ending

79

welded joint

Claims (14)

1. Coolant nozzle (1) for cooling a metallic strand (2) in a continuous casting plant (3), having a mouthpiece (5) which is disposed on a nozzle exit end (4) and through which liquid coolant (6) from the coolant nozzle (1) can exit, comprising an infeed (8) which is configured as a tube-in-tube system (9) and in the throughflow direction (7) is disposed ahead of the mouthpiece (5) and which has an infeed exit end (10), control air (13) being capable of being guided to the infeed exit end (10) through the first tube (11) of said infeed (8), and the liquid coolant (6) being capable of being fed through the second tube (12) of said infeed (8) into the mouthpiece (5) by way of the infeed exit end (10),
   and a switchover valve (14) which is integrated in the infeed (8), is disposed on the infeed exit end (10), and is pneumatically activatable while using the control air (13), wherein the switchover valve (14) is a seat valve having a control piston that is configured as a switching element (15), and the flow through the switchover valve (14) for controlling the infeed of the liquid coolant (6) into the mouthpiece (5) is either opened or closed as a function of the position of the switching element (15), wherein the first tube (11) is an inner tube (11) for the control air (13), and the second tube (12) is an outer tube (12), disposed so as to be substantially concentric with the inner tube (11), for the liquid coolant (6) .
2. Coolant nozzle (1) according to Claim 1,
   characterized in that
   the first tube (11) and/or the second tube (12) are/is configured in multiple parts, in particular are/is configured in multiple parts in such a manner that the parts (11a, 11b, or 12a, 12b, respectively) thereof are capable of being screw-fitted or welded to one another, respectively.
3. Coolant nozzle (1) according to at least the preceding claim,
   characterized in that
   a corrugated bellows (16) guides and seals the switching element (15), in particular the control piston (15).
4. Coolant nozzle (1) according to at least the preceding claim,
   characterized in that
   the corrugated bellows (16) is disposed so as to be concentric on the inner tube (11), in particular is disposed on a second part (11b) of the inner tube (11) that is configured as a corrugated bellows detent (18), on account of which the corrugated bellows (16) is capable of being guided axially relative to the inner tube (11), in particular relative to the corrugated bellows detent (18).
5. Coolant nozzle (1) according to at least one of the preceding claims,
   characterized in that
   the mouthpiece (5) is configured so as to be releasably connected to the coolant nozzle (1), in particular is configured so as to be screw-fittable (21).
6. Coolant nozzle (1) according to at least one of the preceding claims,
   characterized in that
   the infeed exit end (10) is configured as a mouthpiece receptacle (20) to which the mouthpiece (5) is screw-fittable.
7. Coolant nozzle (1) according to at least one of the preceding claims, in particular according to the preceding claim and/or according to Claim 4,
   characterized in that
   the infeed exit end (10), in particular the mouthpiece receptacle (20), is configured as a valve seat (20) for a switching element (15) of the switchover valve (14), in particular for the control piston (15) of the seat valve (14).
8. Coolant nozzle (1) according to at least the preceding claim,
   characterized in that
   a material of the switching element (15), in particular of the control piston (15), and a material of the valve seat (20) are mutually adapted, in particular in that the valve seat (20) has a lesser hardness than the switching element (15), or in that the valve seat (20) has a greater hardness than the switching element (15), wherein the part having the lesser hardness is in particular annealed.
9. Coolant nozzle (1) according to at least one of the preceding claims,
   characterized by
   a connector block (17) which is in particular screw-fittable to the infeed and which in particular has a first connector (24) for the control air (13) and/or a second connector (25) for the liquid coolant (6).
10. Coolant nozzle (1) according to at least the preceding claim,
    characterized in that
    the connector block (17) has a first conduit (26), the first connector (24) being connectable to the first inner tube (11) of the infeed (8) while using said first conduit (26), and/or has a second conduit (27), the second connector (25) being connectable to the second tube (12) of the infeed (8) while using said second conduit (27).
11. Coolant nozzle (1) according to at least one of the preceding claims,
    characterized in that
    the infeed (8) is configured so as to be rectilinear, or is configured bent so as to have at least one bend (23).
12. Cooling installation (50) for cooling a metallic strand (2) in a continuous casting plant (3), having a plurality of nozzle units (40) which in the strand conveying direction (51) are disposed in succession, in particular so as to extend transversely (52) to the strand conveying direction (51), said nozzle units (40) having in each case at least one first coolant nozzle (1, 41) according to at least one of the preceding claims, and having in each case one second coolant nozzle (42) according to at least one of the preceding claims.
13. Cooling installation (50) according to at least the preceding claim,
    characterized in that
    the first coolant nozzles (1, 41) of the plurality of nozzle units (40) are capable of being supplied with the control air (13) by way of a first common control air infeed (43), and/or the second coolant nozzles (1, 42) of the plurality of nozzle units (40) are capable of being supplied with the control air (13) by way of a second common control air infeed (44).
14. Cooling installation (50) according to at least the preceding claim,
    characterized in that
    the control air supply in the first common control air infeed (43) is controlled while using a first control valve (45) that is disposed in the first common control air infeed (43), and/or the control air supply in the second common control air infeed (44) is controlled while using a second control valve (46) that is disposed in the second common control air infeed (44).

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