Spraying device and method for cooling a metallic strand in a continuous casting machine

Description

[0001] The invention relates to a spraying apparatus and a method for cooling a metallic strand in a continuous casting machine.

[0002] European patent EP 2 714 304 B1 discloses a method for cooling a metal strand in a continuous casting machine, in which a spray jet is applied to a metal strand using multiple spray nozzles. In order to be able to vary the amount of spray liquid over the widest possible range, the spray nozzles are designed for a maximum water quantity to be applied and, in order to reduce the amount of spray liquid, are actuated intermittently using switching valves. To set a predetermined amount of spray liquid that is below the maximum dispensable amount of spray liquid, the spray nozzles are thus operated intermittently. Due to the intermittent application of water to the metal strand, its cooling is inevitably discontinuous.

[0003] US patent US 4,247,047 A discloses a spraying device for cooling rollers with several multiple nozzle heads, in which the nozzles in the multiple nozzle heads can be switched on and off using switching valves. The individual nozzles of the multiple nozzle heads are intended to act on different areas of the roller, see Fig. 1, Fig. 2 , Fig. 10, to achieve improved cooling of the rollers through several spaced-apart spray jets. Each multiple nozzle head has several nozzles, each nozzle being assigned a switching valve.

[0004] International Patent Application WO 2017 / 042059 A1 discloses a spray device for cooling a metal strand in a continuous casting machine. To cool the metal strand, several nozzles arranged in an array are provided, each of which can be opened or closed by a switching valve. To achieve a different cooling effect, the nozzles are designed to spray intermittently using pulse-width modulated control signals. To set a predetermined spray fluid quantity that is below the maximum dispensable spray fluid quantity, the spray nozzles are thus operated continuously intermittently. Due to the intermittent application of the metal strand, its cooling is inevitably discontinuous.

[0005] Japanese patent abstract JP S61-049760 A discloses a spray device for cooling a metal strand in a continuous casting machine. Several nozzles arranged side by side are provided for cooling the strand. The spray jets of these nozzles do not overlap.

[0006] Japanese patent abstract JP S57-047560 A also discloses a spray device for cooling a metal strand in a continuous casting machine. Several nozzles arranged side by side are provided for cooling. The spray jets of the individual nozzles do not overlap.

[0007] US Patent No. 7,181,822 B2 discloses a spray device for cooling rollers. It features several nozzles arranged side by side, whose spray jets do not overlap.

[0008] The unpublished international patent application WO 2018 / 224304 A1 discloses a spray device for cooling a metal strand in a continuous casting machine. Numerous nozzles arranged in an array above a metal strand can be intermittently switched on and off to adjust a predetermined spray fluid flow rate. For this purpose, valves can be used to enable or block the supply of spray fluid to a row of adjacent nozzles arranged perpendicular to the direction of movement of the strand.

[0009] The invention aims to improve a spraying apparatus and a method for cooling a metallic strand in a continuous casting machine.

[0010] According to the invention, a spraying apparatus having the features of claim 1 is provided for this purpose. Advantageous further developments of the invention emerge from the subclaims. A spraying apparatus for cooling a metallic strand in a continuous casting machine is provided, in which at least one multiple nozzle head and at least one switching valve are provided, wherein the multiple nozzle head has at least a first and a second nozzle and wherein the switching valve is arranged upstream of the multiple nozzle head, wherein the switching valve is in flow connection with all second nozzles in the multiple nozzle head in order to enable or block a supply of spray liquid to all second nozzles. Preferably, several multiple nozzle heads are provided and the multiple nozzle heads are arranged spatially spaced from one another.

[0011] In the spray gun according to the invention, the output quantity of spray liquid is thus varied by switching nozzles in the multiple nozzle heads on or off. However, with a predetermined and constant quantity of spray liquid, there is no intermittent application, but rather a permanent application of the selected spray liquid pressure to the selected nozzles. This enables continuous operation of the nozzles and thus also continuous cooling of the metallic strand. The nozzles in the multiple nozzle head are designed and arranged in such a way that each nozzle alone and any combination of nozzles each effect a uniform distribution of spray liquid across the width of the metallic strand and thus homogeneous cooling of the strand. This is achieved, among other things, by an overlap of the spray jets of the nozzles.The switching valves can, for example, be designed as pneumatic switching valves and can be controlled, for example, by the level of the pressure of the supplied compressed air. If, for example, there are three nozzles in each of the multiple nozzle heads, the two or three switching valves then present can then be designed so that at a first pressure, for example 6 bar, only the first nozzles are supplied with spray liquid. If the pressure of the supplied compressed air is then reduced, for example to 3 bar, the switching valves open not only for the first nozzles, but also for the second nozzles, so that spray liquid is then dispensed from the first nozzles and the second nozzles. If the pressure of the supplied compressed air is reduced further, for example to 0 bar, all three switching valves open, so that spray liquid is then dispensed through the first nozzles, the second nozzles and the third nozzles in the multiple nozzle heads.Alternatively, the switching valves can also be controlled electrically or electronically, for example by using solenoid valves as the switching valves. A combination of switching valves designed as compressed air valves with solenoid valves is also possible, which then selectively pressurize the switching valves with compressed air in order to change their switching state. A major advantage of the spray gun according to the invention is that the amount of spray liquid dispensed can be varied over a very wide range and yet the spray liquid is still dispensed continuously. The amount of spray liquid dispensed can also be varied by simply exchanging nozzle inserts in the multiple nozzle heads. The amount of spray liquid dispensed can then be varied on the one hand via the pressure of the supplied spray liquid and on the other hand by switching individual nozzles in the multiple nozzle heads on or off.This allows a very large variation range of the spray liquid quantity, for example 1:15, to be achieved. The first nozzle can be permanently supplied with spray liquid, or a switching valve can also be assigned to the first nozzle. The switching valves can be designed so that nozzles in which the spray water supply is shut off are permanently or partially flushed with compressed air in order to prevent deposits and contamination in nozzles and pipes. For this purpose, the switching valves can be provided with a branch for the compressed air and, if necessary, a throttle for the compressed air in the branch. Each multiple nozzle head can be provided with one or more switching valves, or several multiple nozzle heads can be assigned to one or more switching valves.

[0012] In a further development of the invention, each multiple nozzle head has n nozzles, wherein all second nozzles and optionally all third, fourth to n-th nozzles are each in flow connection with a switching valve in order to release or block a supply of spray liquid to all second nozzles and optionally all third, fourth to n-th nozzles, wherein n is a natural number and has a value between 2 and 10.

[0013] The number of nozzles in the multiple nozzle heads is, in principle, arbitrary, with n being advantageously 3, so that each multiple nozzle head contains three nozzles, with a first switching valve assigned to all first nozzles, a second switching valve assigned to all second nozzles, and a third switching valve assigned to all third nozzles. Particularly advantageous values ​​for n are between 2 and 10. The first switching valve can be omitted if the first nozzles are to be continuously supplied with spray fluid.

[0014] In a further development of the invention, at least one first pipeline and one second pipeline are provided for supplying spray liquid, wherein the first pipeline is connected to all first nozzles and the second pipeline is connected to all second nozzles. The first switching valve can be provided upstream of the multiple nozzle heads on the first pipeline, and the second switching valve can be provided upstream of the multiple nozzle heads on the second pipeline.

[0015] By providing pipelines and supplying all first nozzles in the multiple nozzle heads via a common first pipeline and supplying all second nozzles in the multiple nozzle heads via a common second pipeline, a very space-saving design of the spray apparatus according to the invention can be achieved. In continuous casting machines, the nozzles for cooling a metal strand must generally be arranged between support rollers for the metal strand, so that generally only very little space is available for arranging the nozzles. A further significant advantage of shared pipelines is that only a single switching valve needs to be assigned to each pipeline. The design effort can thus be considerably reduced. The first pipeline can be permanently supplied with spray fluid, so that in this case the first switching valve can be omitted.If n nozzles are provided in each multiple nozzle head, n pipes are also present, with one pipe being assigned to each of the first, second, third and nth nozzles, respectively.

[0016] In a further development of the invention, a switching valve is provided upstream of the multiple nozzle heads on the second pipeline and optionally on the third, fourth to n-th pipeline, where n is a natural number and has a value between 2 and 10. A switching valve can also be provided on the first pipeline upstream of the multiple nozzle heads.

[0017] For example, n=3, meaning that three pipelines and three nozzles each are provided in all multiple nozzle heads. At least two of the three lines are each assigned a switching valve, so that a spray liquid supply through the first pipeline is either permanently open or can be blocked or opened using the first switching valve, a spray liquid supply through the second pipeline can be blocked or opened using the second switching valve, and a spray liquid supply through the third pipeline can be blocked or opened using the third switching valve. If a switching valve is present in the first pipeline, all first nozzles in the multiple nozzle heads can be switched on or off together, as can all second nozzles or all third nozzles in the multiple nozzle heads. Particularly advantageous values ​​for n are between 2 and 10.

[0018] In a further development of the invention, the nozzles of at least one multiple nozzle head are different in that they each dispense a different quantity of spray liquid at a predefined pressure of the spray liquid.

[0019] By staggering the nozzle sizes in the multiple nozzle heads in this way, an even wider spread of the spray liquid quantity can be achieved than with identical nozzles, which can be dispensed with the spraying device according to the invention.

[0020] In a further development of the invention, the nozzles of a multiple nozzle head are coordinated with one another with regard to the quantity of spray liquid dispensed in such a way that the first nozzle dispenses a quantity of spray liquid within a first quantity range within a predefined pressure range between a low pressure and a high pressure of the spray liquid, and that the quantity range of the sum of the quantity of spray liquid dispensed by the first nozzle and the second nozzle between the low pressure and the high pressure overlaps the first quantity range.

[0021] In this way, a very wide range of spray fluid quantities can be covered without certain values ​​being missed or missed within this range. In other words, the second quantity range, which is defined by the spray fluid quantities delivered jointly by the first nozzle and the second nozzle between the low pressure and the high pressure, overlaps the first quantity range, at least at the high pressure.

[0022] In a further development of the invention, each multiple nozzle head has n nozzles, wherein the first to third nozzles, the first to fourth nozzles or the first to n-th nozzles optionally dispense a quantity of spray liquid within a third, fourth or n-th quantity range within a predefined pressure range between a low pressure and a high pressure of the spray liquid, and the quantity ranges overlap.

[0023] In this case, too, n is advantageously equal to 3, with further advantageous values ​​of n being between 2 and 10. The second quantity range and the third quantity range thus overlap, as do the third and fourth, or (n-1)th and nth, quantity ranges.

[0024] In a further development of the invention, the multiple nozzle heads are arranged spatially spaced from one another along the pipelines.

[0025] In this way, a compact, space-saving design of the spray gun according to the invention can be achieved. Advantageously, the pipes run parallel to each other. Only short branch lines from the parallel pipes are then required to reach the nozzles of the multiple nozzle heads.

[0026] In a further development of the invention, the pipelines run parallel to a casting direction of the continuous casting machine and the multiple nozzle heads are arranged one behind the other along the pipelines in the casting direction.

[0027] If several spraying devices according to the invention are provided, arranged next to one another in the casting direction, a variation of the width can be achieved by switching off individual spraying devices, which is acted upon by the spraying devices according to the invention, in accordance with the strand width of the metallic strand just cast.

[0028] In a further development of the invention, the pipelines are arranged transversely to a casting direction of the continuous casting machine and the multiple nozzle heads are arranged one behind the other along the pipelines transversely to the casting direction.

[0029] Depending on the intended application, laying the pipes transverse to the casting direction may also be advantageous. A casting direction refers to the feed direction of the metal strand.

[0030] In a further development of the invention, the switching valves are designed as compressed air valves and each switching valve is assigned a solenoid valve for releasing or shutting off a compressed air supply to a respective switching valve.

[0031] In this way, an arrangement can be achieved that appears complex at first glance, but is nevertheless highly reliable. Pneumatic valves can reliably perform their function even under harsh environmental conditions. Solenoid valves, on the other hand, can be easily controlled electronically and easily integrated into a higher-level process control system. The combination of electronically actuated solenoid valves with pneumatic valves therefore ensures a spray gun design according to the invention that is easy to integrate and highly reliable.

[0032] In a further development of the invention, several solenoid valves are combined in a solenoid valve island, wherein the solenoid valve island has a common base and a common electronic control for the solenoid valves.

[0033] This allows for a compact design. The solenoid valve terminal or the solenoid valve terminal's shared electronic control system can be designed for connection to a data bus line, allowing for very simple electronic wiring.

[0034] In a further development of the invention, at least one of the pipelines is designed as a profile with at least one hollow chamber extending in the longitudinal direction of the profile.

[0035] For example, a pultruded or extruded profile made of aluminum, brass, or steel, especially stainless steel, can be used. This allows the pipelines to be constructed very robustly, and the profiles can, for example, already provide mounting options for the multiple nozzle heads.

[0036] In a further development of the invention, several pipelines are formed by means of a profile with several hollow chambers running through the longitudinal direction.

[0037] In this way, a very compact design of the spraying device according to the invention can be achieved.

[0038] In a further development of the invention, several profiles are connected to form a carrier.

[0039] In a further development of the invention, the multiple nozzle heads are arranged on the profile or on the carrier having several profiles.

[0040] By forming a support, the pipelines can simultaneously be designed as mechanically load-bearing parts.

[0041] The problem underlying the invention is also solved by a method for cooling a metallic strand in a continuous casting machine with a spraying device according to the invention, wherein the steps of releasing a spray liquid supply and / or switching off a spray liquid supply to all first nozzles, all second nozzles and / or all n-th nozzles of the multiple nozzle heads are provided as a function of a required spray liquid quantity, wherein the releasing and / or switching off of the spray liquid supply is carried out exclusively when the required spray liquid quantity changes.

[0042] The method according to the invention thus allows for a very large variation in the amount of spray liquid dispensed by the nozzles, while simultaneously achieving a constant spray liquid flow to the metal strand and thus continuous cooling. Individual nozzles can then be switched on or off only when the spray liquid flow changes.

[0043] Further features and advantages of the invention will become apparent from the claims and the following description of preferred embodiments of the invention in conjunction with the drawings.

[0044] The drawings show: Fig. 1 a schematic representation of a spraying apparatus according to the invention according to a first embodiment, Fig. 2 a schematic representation of a multiple nozzle unit with multiple nozzle head of the spray device of the Fig. 1 , Fig. 3 a diagram to explain the spraying device of the Fig. 1 coverable area of ​​dispensed spray liquid quantity, Fig. 4 a schematic representation of a profile for forming several pipes in the spraying apparatus according to the invention, and Fig. 5 a schematic representation of a spraying apparatus not according to the invention according to a second embodiment.

[0045] The representation of the Fig. 1 shows a spraying apparatus 10 according to the invention, which is intended for arrangement in a continuous casting machine in which a metallic strand is produced. A casting direction of the metallic strand is represented by an arrow 12. The casting direction 12 corresponds to the feed direction of the metallic strand. For example, the metallic strand is cast from liquid steel and then transported between support rollers in the direction of the arrow 12. The spraying apparatus according to the invention is then arranged above the metallic strand; a further spraying apparatus 10 according to the invention can be arranged below the metallic strand in order to be able to cool it from the top and bottom. Several spraying apparatuses 10 according to the invention can be arranged next to one another in order to be able to cool, for example, even very wide metallic strands across their entire surface.

[0046] The spray gun 10 according to the invention has a nozzle carrier 14 which extends parallel to the pouring direction 12. On this nozzle carrier 14, several multiple nozzle units 16 are arranged, which are arranged in the Fig. 2 will be explained in more detail later. In the illustrated embodiment, a total of five multiple nozzle units 16 are arranged on the nozzle carrier 14. The number of multiple nozzle units 16 arranged on the nozzle carrier is essentially arbitrary, as is the arrangement on the nozzle carrier 14. In the illustrated embodiment, three multiple nozzle units 16 are arranged on the right side of the nozzle carrier 14 and two multiple nozzle units 16 are arranged on the left side of the nozzle carrier 14. This arrangement is merely exemplary and can be selected essentially arbitrarily. The multiple nozzle units 16 can be permanently connected to the carrier 14 or detachably connected to the carrier 14.

[0047] The nozzle carrier 14 is arranged in a continuous casting machine above the support rollers for the metallic strand. The multiple nozzle units 16 then extend downwards from the nozzle carrier 14, into Fig. 1 i.e. into the drawing plane, so that the spray nozzles can then be arranged, for example, between the support rollers for the metallic strand.

[0048] A first pipe 18a, a second pipe 20a, and a third pipe 22a are provided in the nozzle carrier 14, which run parallel to each other and parallel to the nozzle carrier 14. The first pipe 18a is shown by a solid line, the second pipe 20a by a dashed line, and the third pipe 22a by a dash-dotted line. This is for illustrative purposes only and to distinguish between the three pipes 18a, 20a, and 22a.

[0049] Each multiple nozzle unit 16 has three spray nozzles, each of which is supplied with water by separate nozzle water pipes. To illustrate this in the schematic representation of the Fig. 1 To illustrate this, three nozzle water pipes 18b, 20b, and 22b are shown in each multiple nozzle unit 16. The nozzle water pipes 18b of all multiple nozzle units 16 are connected to the pipeline 18a via short branch lines. The nozzle water pipes 20b of all multiple nozzle units 16 are connected to the second pipeline 20a via short branch lines, and the nozzle water pipes 22b of all multiple nozzle units 16 are connected to the third pipeline 22a via short branch lines. With a suitable structural design of the pipelines 18a, 20a, 22a and the support 14, the branch lines can be omitted.

[0050] Upstream of the multiple nozzle units 16, a nozzle valve block 24 with a total of three switching valves 26, 28, and 30 is provided. The first switching valve 26 is connected to the first pipeline 18a, the second switching valve 28 is connected to the second pipeline 20a, and the third switching valve 30 is connected to the third pipeline 22a. By means of the three switching valves 26, 28, 30, a spray fluid supply, for example, a water supply symbolized by an arrow 32, to the pipelines 18a, 20a, 22a can be opened or closed. The switching valves 26, 28, 30 are advantageously designed as pneumatically controlled pinch valves. The switching valves 26, 28, 30 are pneumatically controlled by means of a solenoid valve each arranged in a solenoid valve island 34 which is shown above the nozzle valve block 24.Compressed air is supplied to this solenoid valve island 34, as symbolized by an arrow 36. Furthermore, the solenoid valve island 34 has a common electronic control system that can be connected to a data bus. Such a data bus, and thus the supply of electrical signals, is symbolized by an arrow 38. Within the scope of the invention, the first switching valve 26 can be omitted if the first pipeline 18a and thus all first nozzles of the multiple nozzle units 16 are to be permanently supplied with spray fluid. A higher-level device for switching the spray water supply on and off for the entire spraying device 10 can, of course, still be provided.

[0051] Depending on how the solenoid valves in the solenoid valve island 34 are controlled, they release or block a compressed air supply to the switching valves 26, 28, 30, and as a result, a spray liquid supply to the pipes 18a, 20a, 22a is then also optionally released or blocked.

[0052] Fig. 2 shows a schematic representation of a multiple nozzle unit 16. Each multiple nozzle unit 16 has a mounting block 40 in which the beginning of the nozzle water pipes 18b, 20b and 22b is arranged. The nozzle water pipes 18b, 20b, 22b then lead through a carrier 42 to a multiple nozzle head 44. In this multiple nozzle head 44, three nozzles 46, 48, 50 are provided, each of which has a Fig. 2 can generate the spray jet indicated schematically. If all three nozzles 46, 48, 50 are in operation, the spray jets of the nozzles 46, 48, 50 overlap. Regardless of whether only one of the nozzles 46, 48, 50 is in operation or any combination of the nozzles 46, 48, 50 is in operation, a homogeneous spray liquid distribution and homogeneous cooling across the entire width of the metallic strand are always achieved. The mounting block 40 connects the multiple nozzle unit 16 permanently or detachably to the carrier 14.

[0053] The multiple nozzle head 44 is designed to be so compact that it can be arranged between two support rollers for the metal strand. In any case, the multiple nozzle head 44 is designed and arranged such that the spray jets generated by the nozzles 46, 48, and 50 can pass unhindered between the support rollers.

[0054] The first nozzle 46 is supplied with spray liquid via the first nozzle water pipe 18b, the second nozzle 48 is supplied with spray liquid via the second nozzle water pipe 20b, and the third nozzle 50 is supplied with spray liquid via the third nozzle water pipe 22b. Ultimately, all first nozzles 46 in the multiple nozzle units 16 are in flow connection with the first pipeline 18a, but all first nozzles 46 are not in flow connection with the second pipeline 20a and the third pipeline 22a. Likewise, all second nozzles 48 of the multiple nozzle units 16 are exclusively in flow connection with the second pipeline 20a. All third nozzles 50 of the multiple nozzle units 16 are exclusively in flow connection with the third pipeline 22a.

[0055] By means of the first switching valve 26, a spray liquid supply to all first nozzles 46 in the multiple nozzle units 16 can be enabled or disabled. By means of the second switching valve 28, a spray liquid supply to all second nozzles 48 in the multiple nozzle units 16 can be enabled or disabled. By means of the third switching valve 30, a spray liquid supply to all third nozzles 50 of the multiple nozzle units 16 can be enabled or disabled.

[0056] If only a comparatively small amount of spray liquid is required to cool a metallic strand, only the nozzles permanently supplied with spray liquid are used, or a higher-level control system (not shown) enables the supply of spray liquid to the first pipeline 18a, for example via the switching valve 26, while blocking the supply of spray liquid to the second pipeline 20a and the third pipeline 22a by means of the switching valves 28, 30. As a result, only the first nozzles 46 will emit a spray jet. The spray jet is emitted by the first nozzles 46 continuously and without interruption. Only when the required amount of spray liquid changes can the pressure of the supplied spray liquid be changed by devices (not shown).On the other hand, all second nozzles 48 can be switched on, for example, via the second switching valve 28. If even more spray fluid is required, all third nozzles 50 can be switched on, for example, via the third switching valve 30.

[0057] The amount of spray liquid dispensed can thus be varied either by changing the pressure of the supplied spray liquid or by switching nozzles 46, 48, and 50 on or off. With a constant, predetermined amount of spray liquid, nozzles 46, 48, and 50 generate a continuous, uninterrupted spray jet. As a result, cooling of the metal strand can also occur continuously and without interruption.

[0058] The first nozzles 46, the second nozzles 48, and the third nozzles 50 in each multiple nozzle head 44 can be identical or designed to deliver different amounts of spray fluid at the same spray fluid pressure. For example, the first nozzle 46 delivers a first amount of spray fluid at a given spray fluid pressure, the second nozzle 48 delivers a larger amount of spray fluid at the same spray fluid pressure, and the third nozzle 50 delivers an even larger amount of spray fluid at the same spray fluid pressure.

[0059] In this way, the spread range of the dispensable spray liquid quantity can be significantly increased compared to three identically designed nozzles 46, 48, 50.

[0060] The nozzles 46, 48, 50 can be configured in the multiple nozzle block 44, for example, as nozzle inserts, so that these nozzle inserts can be replaced quickly and easily. This is advantageous when the nozzles 46, 48, 50 need to be replaced due to wear, but also for adjusting the amount of spray fluid dispensed.

[0061] Fig. 3 shows a diagram in which the discharged spray liquid quantity in liters per minute is plotted against the water pressure of the spray liquid. A first circled line shows the discharged spray liquid quantity by the first nozzles 46 versus the water pressure. A second cross-dotted line shows the sum of the discharged spray liquid quantities by the first nozzle 46 and the second nozzle 48. A third squared line shows the sum of the discharged spray liquid quantities by all three nozzles 46, 48, and 50.

[0062] It can be seen that the first nozzle 46 delivers a spray liquid quantity of only approximately 1 l / min at a spray liquid pressure of 1 bar. At a spray liquid pressure of 12 bar, a spray liquid quantity of approximately 3 l / min is delivered.

[0063] If the spray liquid quantity output is to be increased above 3 l / min, the second nozzle 48 is switched on. At the same time, the spray liquid pressure is reduced back to 1 bar.

[0064] The cross-marked line shows that the sum of the spray liquid quantities delivered by the first nozzle 46 and the second nozzle 48 at a spray liquid pressure of 1 bar is approximately 2 l / min. This value is therefore lower than the spray liquid quantity delivered by the first nozzle 46 alone at a spray liquid pressure of 12 bar. The quantity ranges of the spray liquid quantity delivered by the first nozzle 46 alone and the spray liquid quantity delivered jointly by the first nozzle 46 and the second nozzle 48 thus overlap. This allows very precise adjustment of the spray liquid quantity delivered by varying the spray liquid pressure and switching individual nozzles 46, 48, 50 on or off.

[0065] At a spray fluid pressure of 12 bar, the first nozzle 46 and the second nozzle 48 together deliver approximately 7.5 l / min of spray fluid, as can be seen from the cross-marked line on the far right. If the spray fluid flow rate is to be increased even further, all three nozzles 46, 48, and 50 are supplied with spray fluid, and simultaneously the spray fluid pressure is reduced back to 1 bar. As can be seen from the squared line in Fig. 3 As can be seen, all three nozzles 46, 48, 50 together deliver a spray liquid quantity of approximately 6 l / min at a spray liquid pressure of 1 bar. Here, too, the quantity ranges of the spray liquid quantity delivered jointly by the first nozzle 46 and the second nozzle 48 and the spray liquid quantity delivered jointly by all three nozzles 46, 48, 50 overlap. Of course, an increase in the spray liquid quantity can not only be carried out in the manner described, but nozzles can also be switched on or off at other spray liquid pressures in order to Fig. 3 to be able to set the desired amount of spray agent.

[0066] The nozzles 46, 48, 50 of the multiple nozzle heads 44 are thus coordinated with one another with respect to the spray liquid quantity dispensed such that the first nozzle dispenses a spray liquid quantity within a first quantity range within a predefined pressure range between a low pressure and a high pressure of the spray liquid, and that the sum of the spray liquid quantities dispensed by the first nozzle and the second nozzle at the low pressure is lower than the spray liquid quantity dispensed by the first nozzle at the high pressure. The quantity ranges of the first nozzle, on the one hand, and the spray liquid quantity dispensed jointly by the first nozzle and the second nozzle, on the other hand, thus overlap.Analogously, this also applies to the sum of the spray liquid quantities delivered by the first nozzle and the second nozzle at high pressure and the sum of the spray liquid quantities delivered by the first nozzle, the second nozzle, and the third nozzle together at low pressure. This can be seen from the figures shown in . Fig. 3 This adjustment of the spray liquid quantity can be achieved with three identical nozzles (46, 48, 50) or with three nozzles (46, 48, 50) that differ in terms of the spray liquid quantity delivered.

[0067] Fig. 4 shows schematically the carrier 14 of the Fig. 1 in a front view. The support 14 is formed by a profile 52 having three hollow chambers extending longitudinally. These three hollow chambers form the pipes 18a, 20a, and 22a, to which, as explained, the branch lines to the multiple nozzle units 16 or the multiple nozzle unit 16 itself are connected.

[0068] Undercut grooves 54, 56 are arranged on the sides of the three hollow chambers or pipes 18a, 20a, 22a. These undercut grooves 54, 56 can be used, for example, for mounting the multiple nozzle units 16 on the carrier 14. The carrier 42 of the Fig. 2 , which combines the three nozzle water pipes 18b, 20b, 22b, can be designed in the same or similar way as a profile 52 with several hollow chambers.

[0069] Fig. 5 shows a schematic representation of a spraying apparatus 60 according to the invention according to a further embodiment.

[0070] The spraying device 60 has a multiple nozzle unit 16, as already described in the Fig. 2 The multiple nozzle unit 16 will therefore not be described again.

[0071] In contrast to the multiple nozzle unit 16 of the Fig. 2 On the mounting block 40 of the multiple nozzle unit 16, a nozzle valve block 24 with a total of three switching valves 26, 28 and 30 is arranged, which is already based on the spraying device of the Fig. 1 was explained.

[0072] The first switching valve 26 is assigned to a first nozzle water pipe 18b, the second switching valve 28 is assigned to a second nozzle water pipe 20b, and the third switching valve 30 is assigned to a third nozzle water pipe 22b. Via the switching valves 26, 28, 30, a spray water supply to the nozzle water pipes 18b, 20b, 22b and thus to the nozzles 46, 48 and / or 50 in the multiple nozzle head 44 can be enabled or disabled. A spray liquid supply to the nozzle valve block 24, a compressed air supply to the nozzle valve block 24, and possibly a higher-level solenoid valve island are provided in Fig. 5 not shown for the sake of clarity but in an identical manner as in Fig. 1 provided and in connection with Fig. 1 described.

[0073] The spray gun 60 of the Fig. 5 thus has only one multiple nozzle unit 16. Of course, several spraying devices 60 can be arranged in an arrangement similar to the Fig. 1 Several spraying devices 60 are then provided for cooling a metallic strand. In contrast to the spraying device 10 of the Fig. 1 can be used when several spray guns 60 are Fig. 5 are provided, the individual multiple nozzle units 16 are controlled separately from one another.

Claims

1. Spray apparatus for cooling a metal strand in a continuous casting machine, wherein at least one multiple-nozzle head (44) and at least one switching valve (26, 28, 30) are provided, wherein each multiple-nozzle head (44) has at least a first and a second nozzle (46, 48), wherein the at least one switching valve (26, 28, 30) is arranged upstream of the multiple-nozzle head (44), and wherein the switching valve (26, 28, 30) is flow-connected to all the second nozzles (48) in the multiple-nozzle head, in order to enable or to shut off a supply of spray liquid to all the second nozzles (48), wherein the spray apparatus (10) has a nozzle support (14), which extends parallel to the casting direction (12) and on which a plurality of multiple-nozzle units (16) are arranged, wherein each multiple-nozzle unit (16) has a mounting block (40), in which the beginning of nozzle water pipes (18b, 20b, 22b) is arranged, wherein the nozzle water pipes (18b, 20b, 22b) lead to the multiple-nozzle head (44), and wherein the multiple-nozzle unit (16) is connected in a releasable manner to the nozzle support (14) by way of the mounting block (40), and wherein at least a first and a second switching valve (26, 28, 30) are provided, wherein the first switching valve (26) is flow-connected to all the first nozzles (46) in the multiple-nozzle heads (44), in order to enable or to shut off a supply of spray liquid to all the first nozzles (46), and wherein the second switching valve (28) is flow-connected to all the second nozzles (48) in the multiple-nozzle heads (44), in order to enable or to shut off a supply of spray liquid to all the second nozzles (48).

2. Spray apparatus according to Claim 1, characterized in that a plurality of multiple-nozzle heads (44) are provided, wherein the multiple-nozzle heads (44) are spaced apart from one another in three dimensions.

3. Spray apparatus according to Claim 1 or 2, characterized in that each multiple-nozzle head (44) has n nozzles (46, 48, 50), wherein all the second nozzles (48) and possibly all the third, fourth to nth nozzles (50) are each flow-connected to a switching valve (26, 28, 30), in order to enable or to shut off a supply of spray liquid to all the second nozzles (48) and possibly to all the third, fourth and / or nth nozzles (50), where n is a natural number and has a value between 2 and 10.

4. Spray apparatus according to one of the preceding claims, characterized in that at least a first pipeline (18a) and a second pipeline (20a) are provided for supplying spray liquid, wherein the first pipeline (18a) is connected to all the first nozzles (46) and the second pipeline (20a) is connected to all the second nozzles (48).

5. Spray apparatus according to one of the preceding claims, characterized in that n pipelines (18a, 20a, 22a) are provided, wherein the first pipeline (18a) is connected to all the first nozzles (46), the second pipeline (20a) is connected to all the second nozzles (48) and possibly the third, fourth to nth pipeline (22a) is connected to all the third, fourth and / or nth nozzles (50), where n is a natural number and has a value between 2 and 10.

6. Spray apparatus according to Claim 4 or 5, characterized in that, upstream of the multiple-nozzle heads (44), a respective switching valve (28, 30) is provided on the second pipeline (20a) and possibly on the third, fourth to nth pipeline (22a), where n is a natural number and has a value between 2 and 10.

7. Spray apparatus according to Claim 4, 5 or 6, characterized in that, upstream of the multiple-nozzle heads (44), a switching valve (26) is provided on the first pipeline (18a).

8. Spray apparatus according to at least one of the preceding claims, characterized in that the nozzles (46, 48, 50) of at least one multiple-nozzle head (44) differ to the extent where, at a predefined pressure of the spray liquid, they each discharge a different quantity of spray liquid.

9. Spray apparatus according to one of the preceding claims, characterized in that the nozzles (46, 48, 50) of a multiple-nozzle head (44) are coordinated with one another in respect of the spray-liquid quantity discharged such that the first nozzle (46), within a predefined pressure range between a low pressure and a high pressure of the spray liquid, discharges a spray-liquid quantity within a first quantity range, and that a second quantity range made up of the sum of the spray-liquid quantities discharged by the first nozzle (46) and the second nozzle (48) between the low pressure and the high pressure overlaps the first quantity range.

10. Spray apparatus according to Claim 9, characterized in that each multiple-nozzle head (44) has n nozzles (46, 48, 50), wherein possibly the first to third nozzle (46, 48, 50), the first to fourth nozzle and / or the first to nth nozzle, within a predefined pressure range between a low pressure and a high pressure of the spray liquid, discharge a spray-liquid quantity within a third, fourth and / or nth quantity range, and in that the quantity ranges overlap, where n is a natural number and has a value between 2 and 10.

11. Spray apparatus according to at least one of the preceding claims, characterized in that the switching valves (26, 28, 30) are designed in the form of compressed-air valves, and in that each switching valve (26, 28, 30) is assigned a solenoid valve for enabling or shutting off a supply of compressed air to a respective switching valve.

12. Spray apparatus according to Claim 11, characterized in that a plurality of solenoid valves are combined in a solenoid-valve island, wherein the solenoid-valve island has a joint base and a joint electronic control means for the solenoid valves.

13. Spray apparatus according to at least one of Claims 4 to 7, characterized in that at least one of the pipelines (18a, 20a, 22a) is designed in the form of a profile (52) with at least one hollow chamber which is continuous in the longitudinal direction of the profile (52).

14. Method for cooling a metal strand in a continuous casting machine by means of a spray apparatus according to at least one of the preceding claims, having at least one multiple-nozzle head (44) and at least one switching valve (24, 26, 28), wherein each multiple-nozzle head (44) has at least a first and a second nozzle (46, 48), wherein the at least one switching valve (24, 26, 28) is arranged upstream of the multiple-nozzle head (44), and wherein the switching valve (24, 26, 28) is flow-connected to all the second nozzles (48) in the multiple-nozzle head (44), in order to enable or to shut off a supply of spray liquid to all the second nozzles (48), the method having the following steps: enabling a supply of spray liquid, and / or switching off a supply of spray liquid, to all the second nozzles (48) and / or all the nth nozzles (50) of the multiple-nozzle heads (44) in dependence on a spray-liquid quantity required, wherein the operation of enabling and / or switching off the supply of spray liquid is carried out exclusively when the spray-liquid quantity required is altered, so that, in the case of a constant spray-liquid quantity, the selected nozzles (46, 48, 50) are activated permanently by the selected spray-liquid pressure, and this makes it possible to achieve continuous operation of the nozzles (46, 48, 50) and continuous cooling of the metal strand.

15. Method according to Claim 14, characterized by enabling a supply of spray liquid, or switching off a supply of spray liquid, to all the first nozzles (46) of the multiple-nozzle heads (44) in dependence on a spray-liquid quantity required, wherein the operation of enabling and / or switching off the supply of spray liquid is carried out exclusively when the spray-liquid quantity required is altered.